A single leg switched PWM method for three-phase H-Bridge Voltage Source Converters
DEFF Research Database (Denmark)
Senturk, Osman Selcuk; Helle, Lars; Munk-Nielsen, Stig;
2009-01-01
This paper proposes a single leg switched or a hybrid PWM (HPWM) method for three-phase three-level H-Bridge Voltage Source Converters (3L-HB-VSCs). By means of the proposed modulation, a 3L-HB-VSC can generate the same output as a three-level neutral point clamped (3L-NPC) VSC with phase...... disposition (PD) PWM provided that the outputs of 3L-HBVSC are isolated by transformers or connected to open winding machines. Thus, the proposed method is called PD-HPWM. Moreover, it is emphasized that 3L-HB-VSC with HPWM utilizes its switches similar to 3L-NPC-VSC. Compared to 3L-NPC-VSCs, 3L......-HB-VSCs (without neutral point clamping diodes) have simpler, more modular, and more reliable 2L circuit structure. Therefore, this method encourages the use of 3L-HB-VSCs in the applications utilizing transformers such as grid-side converters of multi-MW wind turbines. The proposed PWM method's performance...
Yamada, Hiroaki; Tanaka, Toshihiko; Funabiki, Shigeyuki
This paper proposes a novel method of suppressing the inrush current of transformers. A small-rated voltage-source PWM converter is connected in series to the transformers through a matching transformer. As the connected PWM converter performs a resistor for the source current, no inrush phenomena occurs. The required-ratings of the PWM converter, which performs the damping resistor for the inrush phenomena, is one-four-hundredth as compared to that of the main transformers in single-phase circuits. In three-phase circuits, it is one-nine-hundredth. The basic principle of the proposed method is discussed. Digital computer simulation is implemented to confirm the validity and excellent practicability of the proposed method using the PSCAD/EMTDC. A prototype experimental-model is constructed and tested. The experimental results demonstrate that the proposed method can perfectly suppress the inrush phenomena.
Passivity-Based Control by Series/Parallel Damping of Single-Phase PWM Voltage Source Converter
del Puerto Flores, Dunstano; Scherpen, Jacqueline; Liserre, Marco; de Vries, Martijn M. J.; Kransse, Marco J.; Monopoli, Vito Giuseppe
2014-01-01
This paper describes a detailed design procedure for passivity-based controllers developed using the Brayton-Moser (BM) framework. Several passivity-based feedback designs are presented for the voltage-source converter, specifically for the H-bridge converter, since nowadays it is one of the preferr
Yamada, Hiroaki; Tanaka, Toshihiko; Funabiki, Shigeyuki
This paper proposes a new inrush current suppressor using a series-connected small-rated PWM converter for a transformer. The PWM converter is directly connected in series between the source and transformer without a matching transformer. The inrush phenomena of the matching transformer, thus, can be avoided. The control gain and required-ratings of the series-connected small-rated PWM converter is discussed in detail. The capacity of the dc capacitor of the PWM converter is also discussed considering the active power flows into the PWM converter. The PSCAD/EMTDC is used to verify the validity of the proposed inrush current suppressor. A prototype experimental model is constructed and tested. The experimental results demonstrate that the proposed suppressor can perfectly overcome the inrush phenomena of transformers.
Step-by-Step Design Procedure for a Grid-Connected Three-Phase PWM Voltage Source Converter,
DEFF Research Database (Denmark)
Liserre, Marco; Blaabjerg, Frede; Aquila, Antonio Dell
2004-01-01
The voltage source active rectifier is one of the most interesting solutions to interfacing dc power systems to the grid. Many elements are responsible for the overall system behaviour, such as value of the passive elements, sensors position, analog/digital filters and ac current/dc voltage...... controllers. In this paper a step-by-step design procedure, taking into account all these elements, is proposed and validated through the tests on an experimental prototype. The reported results are particularly relevant to evaluate the influence on the grid current harmonic content of the grid sensor...... position and of the use of analog filters in the feedback signals....
Research on Passivity Based Controller of Three Phase Voltage Source PWM Rectifier
Directory of Open Access Journals (Sweden)
Yin Hongren
2012-09-01
Full Text Available Euler-Lagrange (EL model of voltage source PWM rectifier is set up based on its model in synchronous dq coordinates. Passivity based controller is designed on the basis of passivity and EL model of voltage source PWM rectifier. Three switching function are educed by passivity based controller. A switching function is only realized in engineering consequently. Voltage source PWM rectifier using passivity based controller has many advantages, such as simpler structure, low total harmonic distortion, and good disturbance rejection performance. Passivity based control law is proved feasible by simulink simulation.
Morimoto, Keiki; Doi, Toshimitsu; Manabe, Haruhiko; Ahmed, Tarek; Hiraki, Eiji; Lee, Hyun-Woo; Nakaoka, Mutsuo
This paper presents a new circuit topology of full-bridge soft-switching PWM inverter linked DC-DC power converter composed of conventional full-bridge high frequency PWM inverter with high frequency transformer and an active quasi-resonant snubber consisting of an additional power switching device in series with DC busline and a lossless capacitor in parallel with DC busline. Under this proposed high frequency soft-switching PWM inverter linked DC-DC converter, four power switches in the full-bridge arms and DC busline series switch can achieve ZVS at turn-off commutation. By developing the advanced soft-switching PWM high frequency inverter type DC-DC converter, although the conduction power loss of DC busline series power switch increases a little, the total turn-off switching loss of full-bridge high frequency inverter power modules can be sufficiently lowered more and more in the higher frequency range of 60kHz. As a result, when the switching frequency of high frequency inverter power stage using IGBT power modules is designed so as to be more than about 10kHz, the more the switching frequency of inverter increases, the more this high frequency soft-switching DC-DC converter has remarkable advantage as for the power conversion efficiency as compared with the conventional hard-switching PWM inverter DC-DC converter. Its practical effectiveness of high power density and high performance is actually proved for TIG arc welding equipment in industry.
Shunt PWM advanced var compensators based on voltage source inverters for Facts applications
Energy Technology Data Exchange (ETDEWEB)
Barbosa, Pedro G.; Misaka, Isamu; Watanabe, Edson H. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia
1994-12-31
Increased attention has been given to improving power system operation. This paper presents modeling, analysis and design of reactive shunt power compensators based on PWM-Voltage Source Inverters (Pulse Width Modulation -Voltage Source Inverters). (Pulse Width Modulation - Voltage Source Inverters). The control algorithm is based on new concepts of instantaneous active and reactive power theory. The objective is to show that with a small capacitor in the side of a 3-phase PWM-VSI it is possible to synthesize a variable reactive (capacitive or inductive) device. Design procedures and experimental results are presented. The feasibility of this method was verified by digital simulations and measurements on a small scale model. (author) 9 refs., 12 figs.
Control Strategy for Three Phase Voltage Source PWM Rectifier Based on the Space Vector Modulation
Directory of Open Access Journals (Sweden)
MILOUD, Y.
2010-08-01
Full Text Available This paper proposes the space vector pulse width modulation (SVPWM control scheme for three-phase voltage source PWM rectifier. The control system based on SVPWM includes two PI controllers which are used to regulate the AC currents and DC-link voltage. The proposed control can stabilize the minimum of the systems storage function at the desired equilibrium point determined by unity power factor and sinusoidal current on the AC side, and constant output voltage on the DC side. So the stable state performance and robustness against the load�s disturbance of PWM rectifiers are both improved. The simulation result shows feasibility of this strategy.
Chen, Juan
2008-01-01
This report is the result of a Master Thesis work done at Seaward Electronics Inc. in Beijing, China from June to December in 2007. The main goal for this thesis is to verify and improve the performance of Honey-PWM DC-DC converter, which has been fabricated by a standard 0.6um CMOS processes. The project was started with studying of Buck converter structure. After the understanding of the converter structure, the project goes in to the analyses phase for each sub-cells, including the theory,...
Analysis of Discontinuous Space Vector PWM Techniques for a Seven-Phase Voltage Source Inverter
Directory of Open Access Journals (Sweden)
Mohd. Arif Khan
2012-03-01
Full Text Available This paper presents discontinuous space vector PWM (DPWM techniques for a seven-phase voltage source inverter (VSI. Space vector model of a seven-phase VSI shows that there exist 128 space vectors with different lengths and maps into fourteen sided polygons. A number of possibilities could arise to implement modulation of inverter legs due to large number of available space voltage vectors. Two strategies are adopted here; one utilising large and two middle sets of space vectors to implement discontinuous space vector PWM. Clamping of legs of inverter to either positive or negative dc bus leads to discontinuity in the switching and consequently offers reduced switching loss modulation strategy. A significant reduction in switching losses can be achieved while employing DPWM in a seven-phase VSI. A generalised method is also proposed to realize the DPWM in a seven-phase VSI. Comparison of continuous and discontinuous PWM is presented in terms of switching current ripple. The experimental set-up is illustrated and the experimental results are presented.
PWM Converter Power Density Barriers
Kolar, Johann W.; Drofenik, Uwe; Biela, Juergen; Heldwein, Marcelo; Ertl, Hans; Friedli, Thomas; Round, Simon
Power density of power electronic converters has roughly doubled every 10 years since 1970. Behind this trajectory is the continuous advancement of power semiconductor devices, which has increased the converter switching frequencies by a factor of 10 every decade. However, today's cooling concepts and passive components are major barriers for a continuation of this trend. To identify such technological barriers, this paper investigates the volume of the cooling system and passive components as a function of the switching frequency for power electronic converters and determines the switching frequency that minimizes the total volume. A power density limit of 28kW/dm3 at 300kHz is calculated for an isolated DC-DC converter, 44kW/dm3 at 820kHz for a three-phase unity power factor PWM rectifier, and 26kW/dm3 at 21kHz for a sparse matrix converter. For single-phase AC-DC conversion a general limit of 35kW/dm3 results from the DC link capacitor. These power density limits highlight the need to broaden the scope of power electronics research to include cooling systems, high frequency electromagnetics, interconnection and packaging technology, and multi-domain modelling and simulation to ensure further advancement along the power density trajectory.
IGBT Fuses for Protection Against Explosion in Voltage Source Converters
DEFF Research Database (Denmark)
Blaabjerg, Frede; Iov, Florin; Rasmussen, H.
2004-01-01
The consequences of electrical faults can be severe; not only to the equipment, but also in the worse case, to people if safety principles are not observed. Every year new applications based on DC-link Voltage Source Converters are added and the demand for protection of power electronics increases...... regarding the high-power IGBT modules. Due to the fact that the power level increases more energy is stored in the DC-link and even with an active protection, a high-power IGBT still has a risk of case rupture (explode) when a circuit failure condition occurs. A possible solution is a protection...... of the converter with standard High Speed Fuses or High Speed IGBT fuses. It is discussed that protection can be achieved by introduction of IGBT fuse located in the DC-link. Experiments show that explosion can be avoided by use of High Speed Fuse protection and the added inductance of standard High Speed...
Dynamic Performance of a Back-to-Back HVDC Station Based on Voltage Source Converters
Khatir, Mohamed; Zidi, Sid-Ahmed; Hadjeri, Samir; Fellah, Mohammed-Karim
2010-01-01
The recent developments in semiconductors and control equipment have made the voltage source converter based high voltage direct current (VSC-HVDC) feasible. This new DC transmission is known as "HVDC Light or "HVDC Plus by leading vendors. Due to the use of VSC technology and pulse width modulation (PWM) the VSC-HVDC has a number of potential advantages as compared with classic HVDC. In this paper, the scenario of back-to-back VSC-HVDC link connecting two adjacent asynchronous AC networks is studied. Control strategy is implemented and its dynamic performances during disturbances are investigated in MATLAB/Simulink program. The simulation results have shown good performance of the proposed system under balanced and unbalanced fault conditions.
Improved direct power control of a grid-connected voltage source converter during network unbalance
Institute of Scientific and Technical Information of China (English)
Peng ZHOU; Wei ZHANG; Yi-kang HE; Rong ZENG
2010-01-01
This paper deals with an improved direct power control(DPC)strategy for the pulse width modulation(PWM)voltage source converter(VSC)under unbalanced grid voltage conditions.In order to provide enhanced control performance for the VSC,the resonant controllers tuned at the double grid frequency are applied in the DPC design to eliminate the power pulsations and dc link voltage ripples produced by the transient unbalanced grid faults.In this way,the output power and dc link voltage of the VSC can be directly regulated without positive and negative sequential decomposition.As a result,and as has been verified by experiment,the proposed method can provide fast dynamic response with easy implementation.
Analysis of Peak-to-Peak Current Ripple Amplitude in Seven-Phase PWM Voltage Source Inverters
Directory of Open Access Journals (Sweden)
Gabriele Grandi
2013-08-01
Full Text Available Multiphase systems are nowadays considered for various industrial applications. Numerous pulse width modulation (PWM schemes for multiphase voltage source inverters with sinusoidal outputs have been developed, but no detailed analysis of the impact of these modulation schemes on the output peak-to-peak current ripple amplitude has been reported. Determination of current ripple in multiphase PWM voltage source inverters is important for both design and control purposes. This paper gives the complete analysis of the peak-to-peak current ripple distribution over a fundamental period for multiphase inverters, with particular reference to seven-phase VSIs. In particular, peak-to-peak current ripple amplitude is analytically determined as a function of the modulation index, and a simplified expression to get its maximum value is carried out. Although reference is made to the centered symmetrical PWM, being the most simple and effective solution to maximize the DC bus utilization, leading to a nearly-optimal modulation to minimize the RMS of the current ripple, the analysis can be readily extended to either discontinuous or asymmetrical modulations, both carrier-based and space vector PWM. A similar approach can be usefully applied to any phase number. The analytical developments for all different sub-cases are verified by numerical simulations.
Directory of Open Access Journals (Sweden)
Z.A. Jaffery
2012-10-01
Full Text Available The authors present the design, simulation and analysis of a single phase voltage source inverter using soft switching techniques. The performance of the inverter has been compared in terms of harmonic contents present in output voltage and current. The research works for a PWM inverter along with a LLCC filter has been investigated. This paper also investigated the performance of the same inverter with a feedback controller with a closed loop feedback path to maintain rated output voltage. This work is helpful for the inverter used in application where high quality ac wave is prime requirement
Voltage Source Inverter/Converter for the Improvement of Power Quality Using Fuzzy Logic Controller
Directory of Open Access Journals (Sweden)
T Jagan Mohan Rao
2014-05-01
Full Text Available In recent years, the applications of power electronics have grown tremendously. These power electronic systems offer highly nonlinear characteristics. To overcome those non linearities active power filters are preferred. This paper presents and compares the performance of two controllers namely Fuzzy Logic and Proportional Integral (PI applied to a voltage source inverter / converter which operates as an active power filter. The active power filter is operated to compensate harmonics generated by the non-linear load . This work is done to make an accurate comparison of the performance of fuzzy logic controller and classical control technique such as PI controller in compensating harmonics in the ac mains current. Fuzzy control rule design is based on the general dynamic behavior of the process. A novel control method is implemented for suppressing the harmonics. The compensation process is instantaneous, which is achieved without employing any complicated control logic. The control scheme is based on sensing line currents only; an approach different from convention ones, which are based on sensing harmonics of the nonlinear load. In the control scheme a hysteresis controller based on current control is employed to generate switching signals to the PWM converter.
Directory of Open Access Journals (Sweden)
Abdelkrim Thameur
2015-01-01
Full Text Available This paper proposes a regulation method of back-to-back connected two-level PWM rectifier-five-level Voltage Source Inverter (VSI in order to reduce the torque ripple in induction motor. First part is dedicated to the presentation of the feedback control of two-level PWM rectifier. In the second part, five-level Neutral Point Clamped (NPC voltage source inverter balancing DC bus algorithm is presented. A theoretical analysis with a complete simulation of the system is presented to prove the excellent performance of the proposed technique.
Large-signal stability analysis of PWM converters
Energy Technology Data Exchange (ETDEWEB)
Huynh, P.T. [Philips Labs., Briarcliff Manor, NY (United States); Cho, B.H. [Seoul National Univ. (Korea, Republic of). Dept. of Electrical Engineering
1995-12-31
Investigation of the effects of existing nonlinearities on the stability of PWM converters is performed. The bilinear structure, the duty cycle saturation, and the opamp saturation are the principal nonlinearities in PWM converters. These nonlinearities are incorporated in the large-signal analytical models of PWM converters, and the basic input-output stability theory is applied to analyze their stability. Design and optimization of the small-signal loop gains to counteract the undesirable nonlinear effects are also discussed.
Comparative Analysis of PWM Techniques for Three Level Diode Clamped Voltage Source Inverter
Directory of Open Access Journals (Sweden)
Zulkifilie Bin Ibrahim
2014-07-01
Full Text Available Multilevel inverters are increasingly being used in high-power medium voltage industrial drive applications due to their superior performance compared to conventional two-level inverters. Thre are a number of Pulse width modulation (PWM techniques applied in recent years. The most widely applied PWM techniques are Sine Pulse Width Modulation (SPWM and Space Vector Pulse Width Modulation (SVPWM. SPWM is the most simple modulation technique that can realize easily in analog circuit. However, it has some drawbacks such as higher total harmonic distortion (THD, lower effective DC utilization and lower switching frequency. Space vector pulse width modulation (SVPWM is widely used because of their easier digital realization and better DC bus utilization and lower THD. The complexity is due to the difficulty in determining the reference vector location, on times calculation, and switching states selection. This paper presents a simple SVPWM algorithm for diode clamped three level inverters based on standard two-level SVPWM which can easily determine the location of reference vector, calculate the on-times, the selection of switching states. Three level diode clamped inverter (3LDCI using space vector modulation technique has been modeled and simulated using MATLAB/SIMULINK and Origin 6.1 with a passive R-L load that can be extended to any level. Simulation results are presented to verify the proposed SVPWM control in terms of THD. The results are compared with conventional sinusoidal pulse width modulation (SPWM where SVPWM shows better performance than SPWM in terms of THD.
DEFF Research Database (Denmark)
Gohil, Ghanshyamsinh Vijaysinh; Maheshwari, Ram Krishan; Bede, Lorand;
2015-01-01
for the maximum value of the flux linkage are derived for each of these PWM schemes. In addition, the effect of the proposed PWM scheme on the line current ripple and the switching losses is also analyzed and compared. To verify the analysis, experimental results are presented, which prove the effectiveness......Parallel voltage-source converters (VSCs) require an inductive filter to suppress the circulating current. The size of this filter can be minimized by reducing either the maximum value of the flux linkage or the core losses. This paper presents a modified discontinuous pulsewidth modulation (DPWM......) scheme to reduce the maximum value of the flux linkage and the core losses in the circulating current filter. In the proposed PWM scheme, the dwell time of an active vector is divided within a half-carrier cycle to ensure simultaneous occurrence of the same zero vectors in both VSCs. A function to decide...
An Integrated Inductor For Parallel Interleaved Three-Phase Voltage Source Converters
DEFF Research Database (Denmark)
Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Teodorescu, Remus;
2016-01-01
Three phase Voltage Source Converters (VSCs) are often connected in parallel to realize high current output converter system. The harmonic quality of the resultant switched output voltage can be improved by interleaving the carrier signals of these parallel connected VSCs. As a result, the line...
Miller, Stephanie Katherine Teixeira
Of all the alternative and renewable energy sources, wind power is the fastest growing alternative energy source with a total worldwide capacity of over 93 GW as of the end of 2007. However, making wind energy a sustainable and reliable source of electricity doesn't come without its set of challenges. As the wind turbines increase in size and turbine technology moves towards off-shore wind farms and direct drive transmission, the need for a reliable and efficient power electronics interface to convert the variable-frequency variable-magnitude output of the wind turbine's generator into the fixed-frequency fixed-magnitude voltage of the utility grid is critical. This dissertation investigates a power electronics interface envisioned to operate with an induction generator-based variable-speed wind turbine. The research conclusions and the interface itself are applicable to a variety of applications, including uninterruptible power supplies, industrial drives, and power quality applications, among others. The three-phase PWM rectifiers with ac-side bidirectional switches are proposed as the rectification stage of the power electronics interface. Modulation strategies are proposed for the rectifiers and the operation of the rectifiers in conjunction with an induction generator is demonstrated. The viability of using these rectifiers in place of the standard three-phase voltage-source converter is analyzed by comparing losses and common-mode voltage generation of the two topologies. Parallel three-phase voltage-source converter modules operated in an interleaved fashion are proposed for the inversion stage of the power electronics interface. The interleaved three-phase voltage-source converters are analyzed by deriving analytical models for the common-mode voltage, ac phase current, and dc-link current to reveal their spectra and the harmonic cancellation effects of interleaving. The practical problem of low frequency circulating current in parallel voltage-source
Influence of current limitation on voltage stability with voltage sourced converter HVDC
DEFF Research Database (Denmark)
Zeni, Lorenzo; Jóhannsson, Hjörtur; Hansen, Anca Daniela;
2013-01-01
A first study of voltage stability with relevant amount of Voltage Sourced Converter based High Voltage Direct Current (VSC-HVDC) transmission is presented, with particular focus on the converters’ behaviour when reaching their rated current. The detrimental effect of entering the current...
Investigation of Grid-connected Voltage Source Converter Performance under Unbalanced Faults
DEFF Research Database (Denmark)
Jia, Jundi; Yang, Guangya; Nielsen, Arne Hejde
2016-01-01
Renewable energy sources (RES) and HVDC links are typically interfaced with the grid by power converters, whose performance during grid faults is significantly different from that of traditional synchronous generators. This paper investigates the performance of grid-connected voltage source...
DEFF Research Database (Denmark)
Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang
2015-01-01
Active damping and harmonic compensation are two common challenges faced by LCL-filtered voltage source converters. To manage them holistically, this paper begins by proposing a virtual RC damper in parallel with the passive filter capacitor. The virtual damper is actively inserted by feeding back...... in the laboratory with results obtained for demonstrating stability and harmonic compensation....
Institute of Scientific and Technical Information of China (English)
Jia-bing HU; Wei ZHANG; Hong-sheng WANG; Yi-kang HE; Lie XU
2009-01-01
This paper proposes a current control scheme for a grid-connected pulse width modulator (PWM) voltage source converter (GC-VSC) under imbalanced and distorted supply voltage conditions. The control scheme is implemented in the positive synchronously rotating reference frame and composed of a single proportional integral (PI) regulator and multi-frequency resonant controllers tuned at the frequencies of 2ω and 6ω, respectively. The experimental results, with the target of eliminating the active power oscillations and current harmonics on a prototype GC-VSC system, validate the feasibility of the proposed current control scheme during supply voltage imbalance and distortion.
Voltage source ac-to-dc converters for high-power transmitters
Cormier, R.
1990-01-01
This work was done to optimize the design of the components used for the beam power supply, which is a component of the transmitters in the Deep Space Network (DSN). The major findings are: (1) the difference in regulation between a six-pulse and a twelve-pulse converter is at most 7 percent worse for the twelve-pulse converter; (2) the commutation overlap angle of a current source converter equals that of a voltage source converter with continuous line currents; (3) the sources of uncharacteristic harmonics are identified with SPICE simulation; (4) the use of an imperfect phase-shifting transformer for the twelve-pulse converter generates a harmonic at six times the line frequency; and (5) the assumptions usually made in analyzing converters can be relaxed with SPICE simulation. The results demonstrate the suitability of using SPICE simulation to obtain detailed performance predictions of ac-to-dc converters.
A Unified Impedance Model of Voltage-Source Converters with Phase-Locked Loop Effect
DEFF Research Database (Denmark)
Wang, Xiongfei; Harnefors, Lennart; Blaabjerg, Frede
2016-01-01
This paper proposes a unified impedance model for analyzing the effect of Phase-Locked Loop (PLL) on the stability of grid-connected voltage-source converters. In the approach, the dq-frame impedance model is transformed into the stationary αβ-frame by means of complex transfer functions and comp......This paper proposes a unified impedance model for analyzing the effect of Phase-Locked Loop (PLL) on the stability of grid-connected voltage-source converters. In the approach, the dq-frame impedance model is transformed into the stationary αβ-frame by means of complex transfer functions...... characterized for the current control in the rotating dq-frame and the stationary αβ-frame. Case studies based on the unified impedance model are presented, which are then verified in the time-domain simulations and experiments. The results closely correlate with the impedance-based analysis....
A Unified Impedance Model of Voltage-Source Converters with Phase-Locked Loop Effect
DEFF Research Database (Denmark)
Wang, Xiongfei; Harnefors, Lennart; Blaabjerg, Frede
2016-01-01
This paper proposes a unified impedance model for analyzing the effect of Phase-Locked Loop (PLL) on the stability of grid-connected voltage-source converters. In the approach, the dq-frame impedance model is transformed into the stationary αβ-frame by means of complex transfer functions and comp......This paper proposes a unified impedance model for analyzing the effect of Phase-Locked Loop (PLL) on the stability of grid-connected voltage-source converters. In the approach, the dq-frame impedance model is transformed into the stationary αβ-frame by means of complex transfer functions...... and complex space vectors, which not only predicts the stability impact of the PLL, but reveals also its frequency coupling effect in the phase domain. Thus, the impedance models previously developed in the different domains can be unified. Moreover, the impedance shaping effects of PLL are structurally...
三相电压型PWM整流器自抗扰控制%Active Disturbance Rejection Control of Three-Phase Voltage Source PWM Rectifiers
Institute of Scientific and Technical Information of China (English)
刘子建; 吴敏; 王春生; 桂武鸣; 陈鑫
2011-01-01
Based on the nonlinear characteristic of three-phase voltage source PWM rectifiers, a nonlinear control strategy is proposed. The voltage and current controllers are designed by using active disturbance rejection control (ADRC) technique, and then, the controllers have the advantage of robustness. The load disturbance is compensated by the voltage controller, which effectively removes the static tracking error of the output direct current (DC) voltage, which is caused by the disturbance. The switching signals of the three-phase voltage source PWM rectifiers are generated by space vector pulse width modulation (PWM) method. Simulation results show the effectiveness of the presented control strategy.%针对三相电压型PWM整流器本身的非线性特点,提出一种非线性控制策略.采用自抗扰控制技术设计了电压和电流控制器,具有鲁棒性强的特点.通过电压控制器对负载扰动进行补偿,消除了负载扰动带来的输出直流电压稳态跟踪误差.三相电压型PWM整流器的开关信号利用空间矢量脉宽调制方法生成.仿真结果表明,本文所提控制策略是有效的,
Estimation of the Plant Time Constant of Current-Controlled Voltage Source Converters
DEFF Research Database (Denmark)
Vidal, Ana; Yepes, Alejandro G.; Malvar, Jano
2014-01-01
Precise knowledge of the plant time constant is essential to perform a thorough analysis of the current control loop in voltage source converters (VSCs). As the loop behavior can be significantly influenced by the VSC working conditions, the effects associated to converter losses should be included...... of the VSC interface filter measured at rated conditions. This paper extends that method so that both parameters of the plant time constant (resistance and inductance) are estimated. Such enhancement is achieved through the evaluation of the closed-loop transient responses of both axes of the synchronous...
Virtual-Impedance-Based Control for Voltage-Source and Current-Source Converters
DEFF Research Database (Denmark)
Wang, Xiongfei; Li, YunWei; Blaabjerg, Frede;
2015-01-01
The virtual impedance concept is increasingly used for the control of power electronic systems. Generally, the virtual impedance loop can either be embedded as an additional degree of freedom for active stabilization and disturbance rejection, or be employed as a command reference generator...... for the converters to provide ancillary services. This paper presents an overview of the virtual-impedance-based control strategies for voltage-source and current-source converters. The control output impedance shaping attained by the virtual impedances is generalized first using the impedance-based models...
An Impedance-Based Stability Analysis Method for Paralleled Voltage Source Converters
DEFF Research Database (Denmark)
Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang
2014-01-01
This paper analyses the stability of paralleled voltage source converters in AC distributed power systems. An impedance-based stability analysis method is presented based on the Nyquist criterion for multiloop system. Instead of deriving the impedance ratio as usual, the system stability...... is assessed based on a series of Nyquist diagrams drawn for the terminal impedance of each converter. Thus, the effect of the right half-plane zeros of terminal impedances in the derivation of impedance ratio for paralleled source-source converters is avoided. The interaction between the terminal impedance...... of converter and the passive network can also be predicted by the Nyquist diagrams. This method is applied to evaluate the current and voltage controller interactions of converters in both grid-connected and islanded operations. Simulations and experimental results verify the effectiveness of theoretical...
Investigation of Grid-connected Voltage Source Converter Performance under Unbalanced Faults
DEFF Research Database (Denmark)
Jia, Jundi; Yang, Guangya; Nielsen, Arne Hejde
2016-01-01
Renewable energy sources (RES) and HVDC links are typically interfaced with the grid by power converters, whose performance during grid faults is significantly different from that of traditional synchronous generators. This paper investigates the performance of grid-connected voltage source...... that the performance of VSCs varies with their control strategies. Negative-sequence current control is necessary to restrict converter current in each phase under unbalanced faults. Among presented control strategies, the balanced current control strategy complies with the present voltage support requirement best...... converters (VSCs) under unbalanced faults. Conventional positive-sequence synchronous reference frame (SRF) control is presented first, followed by three different negative-sequence current control strategies considering reactive power injection and converter current limit. The simulation results indicate...
Design, Control, and Modeling of a New Voltage Source Converter for HVDC System
Mohan, Madhan; Singh, Bhim; Ketan Panigrahi, Bijaya
2013-05-01
Abstract: A New Voltage Source Converter (VSC) based on neutral clamped three-level circuit is proposed for High Voltage DC (HVDC) system. The proposed VSC is designed in a multipulse configuration. The converter is operated by Fundamental Frequency Switching (FFS). A new control method is developed for achieving all the necessary control aspects of HVDC system such as independent real and reactive power control, bidirectional real and reactive power control. The basic of the control method is varying the pulse width and by keeping the dc link voltage constant. The steady state and dynamic performances of HVDC system interconnecting two different frequencies network are demonstrated for active and reactive power control. Total number of transformers used in this system are reduced to half in comparison with the two-level VSCs for both active and reactive power control. The performance of the HVDC system is improved in terms of reduced harmonics level even at fundamental frequency switching. The harmonic performance of the designed converter is also studied for different value of the dead angle (β), and the optimized range of the dead angle is achieved for varying reactive power requirement. Simulation results are presented for the designed three level multipulse voltage source converters with the proposed control algorithm.
A Unified Impedance Model of Grid-Connected Voltage-Source Converters
DEFF Research Database (Denmark)
Wang, Xiongfei; Harnefors, Lennart; Blaabjerg, Frede
2017-01-01
This paper proposes a unified impedance model of grid-connected voltage-source converters for analyzing dynamic influences of the Phase-Locked Loop (PLL) and current control. The mathematical relations between the impedance models in the different domains are first explicitly revealed by means...... of complex transfer functions and complex space vectors. A stationary (αβ-) frame impedance model is then proposed, which not only predicts the stability impact of the PLL, but reveals also its frequency coupling effect explicitly. Furthermore, the impedance shaping effect of the PLL on the current control...
High-performance feedback-type active damping of LCL-filtered voltage source converters
DEFF Research Database (Denmark)
Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang
2015-01-01
Active damping of LCL-filter resonance based on single-state feedback control is widely used with voltage source converters. Its robustness against grid impedance variation has always been a major concern with its controller design. To deal with this issue, this paper begins by developing......, but ensures also a robust stabilization against the grid parameters variations. For illustration, the approach is applied to design three single-state feedback-damping schemes, and their damping robustness are compared under both inductive and resonant grid impedances. Experimental results validate...
Analytical Method to Calculate the DC Link Current Stress in Voltage Source Converters
DEFF Research Database (Denmark)
Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Teodorescu, Remus;
2014-01-01
The dc-link capacitor is one of the critical components, which influences the lifetime of the whole voltage source converter unit. For reliable design, the operating temperature of the dc-link capacitor should be known, which is primarily determined by the ambient temperature and the rms value...... of the current flowing through the dc-link capacitor. A simple analytical method to calculate the rms value of the dc-link capacitor current is presented in this paper. The effect of the line current ripple on the rms value of the dc-link capacitor current is considered. This yields accurate results, especially...
Indian Academy of Sciences (India)
Manoj Kumar Modi; S Venugopal; G Narayanan
2013-06-01
The equivalence of triangle-comparison-based pulse width modulation (TCPWM) and space vector based PWM (SVPWM) during linear modulation is well-known. This paper analyses triangle-comparison based PWM techniques (TCPWM) such as sine-triangle PWM (SPWM) and common-mode voltage injection PWM during overmodulation from a space vector point of view. The average voltage vector produced by TCPWM during overmodulation is studied in the stationary (a–b) reference frame. This is compared and contrasted with the average voltage vector corresponding to the well-known standard two-zone algorithm for space vector modulated inverters. It is shown that the two-zone overmodulation algorithm itself can be derived from the variation of average voltage vector with TCPWM. The average voltage vector is further studied in a synchronously revolving (d-q) reference frame. The RMS value of low-order voltage ripple can be estimated, and can be used to compare harmonic distortion due to different PWM methods during overmodulation. The measured values of the total harmonic distortion (THD) in the line currents are presented at various fundamental frequencies. The relative values of measured current THD pertaining to different PWM methods tally with those of analytically evaluated RMS voltage ripple.
Dynamics of voltage source converter in a grid connected solar photovoltaic system
DEFF Research Database (Denmark)
Haribabu, Divyanagalakshmi; Vangari, Adithya; Sakamuri, Jayachandra N.
2015-01-01
This paper emphasises the modelling and control of a voltage source converter (VSC) for three phase grid connected PV system. The transfer functions for inner current control and outer DC link voltage control for VSC are derived. The controllers for VSC are designed based on PI and K factor contr...... conditions. The effectiveness of the proposed controller is illustrated by evaluating the response of PV system for power system voltage sag and swell conditions as well as grid faults.......This paper emphasises the modelling and control of a voltage source converter (VSC) for three phase grid connected PV system. The transfer functions for inner current control and outer DC link voltage control for VSC are derived. The controllers for VSC are designed based on PI and K factor control...... methods and the performance of VSC using both the methods are presented with the simulations performed using PSCAD/EMTDC. The design of LC filter to meet the specified THD requirement for grid connected VSC is presented and the corresponding harmonic analysis is performed for different solar radiation...
Passivity-based design of robust passive damping for LCL-filtered voltage source converters
DEFF Research Database (Denmark)
Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang
2015-01-01
Passive damping is proven as a robust stabilizing technique for LCL-filtered voltage source converters. However, conventional design methods of passive dampers are based on the passive components only, while the inherent damping effect of time delay in the digital control system is overlooked....... In this paper, a frequency-domain passivity-based design approach is proposed, where the passive dampers are designed to eliminate the negative real part of the converter output admittance with closed-loop current control, rather than shaping the LCL-filter itself. Thus, the influence of time delay...... in the current control is included, which allows a relaxed design of the passive damper with the reduced power loss and improved stability robustness against grid parameters variations. Design procedures of two commonly used passive dampers with LCL-filtered VSCs are illustrated. Experimental results validate...
Estimation of the Plant Time Constant of Current-Controlled Voltage Source Converters
DEFF Research Database (Denmark)
Vidal, Ana; Yepes, Alejandro G.; Malvar, Jano;
2014-01-01
Precise knowledge of the plant time constant is essential to perform a thorough analysis of the current control loop in voltage source converters (VSCs). As the loop behavior can be significantly influenced by the VSC working conditions, the effects associated to converter losses should be included...... of the VSC interface filter measured at rated conditions. This paper extends that method so that both parameters of the plant time constant (resistance and inductance) are estimated. Such enhancement is achieved through the evaluation of the closed-loop transient responses of both axes of the synchronous...... in the model, through an equivalent series resistance. In a recent work, an algorithm to identify this parameter was developed, considering the inductance value as known and practically constant. Nevertheless, the plant inductance can also present important uncertainties with respect to the inductance...
Power electronic converters PWM strategies and current control techniques
Monmasson, Eric
2013-01-01
A voltage converter changes the voltage of an electrical power source and is usually combined with other components to create a power supply. This title is devoted to the control of static converters, which deals with pulse-width modulation (PWM) techniques, and also discusses methods for current control. Various application cases are treated. The book is ideal for professionals in power engineering, power electronics, and electric drives industries, as well as practicing engineers, university professors, postdoctoral fellows, and graduate students.
Nonlinear control of voltage source converters in AC-DC power system.
Dash, P K; Nayak, N
2014-07-01
This paper presents the design of a robust nonlinear controller for a parallel AC-DC power system using a Lyapunov function-based sliding mode control (LYPSMC) strategy. The inputs for the proposed control scheme are the DC voltage and reactive power errors at the converter station and the active and reactive power errors at the inverter station of the voltage-source converter-based high voltage direct current transmission (VSC-HVDC) link. The stability and robust tracking of the system parameters are ensured by applying the Lyapunov direct method. Also the gains of the sliding mode control (SMC) are made adaptive using the stability conditions of the Lyapunov function. The proposed control strategy offers invariant stability to a class of systems having modeling uncertainties due to parameter changes and exogenous inputs. Comprehensive computer simulations are carried out to verify the proposed control scheme under several system disturbances like changes in short-circuit ratio, converter parametric changes, and faults on the converter and inverter buses for single generating system connected to the power grid in a single machine infinite-bus AC-DC network and also for a 3-machine two-area power system. Furthermore, a second order super twisting sliding mode control scheme has been presented in this paper that provides a higher degree of nonlinearity than the LYPSMC and damps faster the converter and inverter voltage and power oscillations.
New PWM switched-mode converter topologies
Hua, Gui-Chao; Huang, Shi-Peng
Two augmented switching cells are proposed from which four novel topologies can be derived: an augmented buck converter, an augmented boost converter, a novel switching power amplifier, and a novel switching controlled rectifier. The augmented buck and the augmented boost converters realize higher step-down and step-up ratios, respectively, under a given switch duty ratio by proper design of the turn ratios of the transformer and coupled inductor. The switching power amplifier achieves four-quadrant output by the use of two bidirectional current switches and a single power supply, while the inverse converter can be used as a switching controlled rectifier. The experimental verification of the power amplifier is presented.
Optimized Controller Design for a 12-Pulse Voltage Source Converter Based HVDC System
Agarwal, Ruchi; Singh, Sanjeev
2017-08-01
The paper proposes an optimized controller design scheme for power quality improvement in 12-pulse voltage source converter based high voltage direct current system. The proposed scheme is hybrid combination of golden section search and successive linear search method. The paper aims at reduction of current sensor and optimization of controller. The voltage and current controller parameters are selected for optimization due to its impact on power quality. The proposed algorithm for controller optimizes the objective function which is composed of current harmonic distortion, power factor, and DC voltage ripples. The detailed designs and modeling of the complete system are discussed and its simulation is carried out in MATLAB-Simulink environment. The obtained results are presented to demonstrate the effectiveness of the proposed scheme under different transient conditions such as load perturbation, non-linear load condition, voltage sag condition, and tapped load fault under one phase open condition at both points-of-common coupling.
Grid Integration of Single Stage Solar PV System using Three-level Voltage Source Converter
Hussain, Ikhlaq; Kandpal, Maulik; Singh, Bhim
2016-08-01
This paper presents a single stage solar PV (photovoltaic) grid integrated power generating system using a three level voltage source converter (VSC) operating at low switching frequency of 900 Hz with robust synchronizing phase locked loop (RS-PLL) based control algorithm. To track the maximum power from solar PV array, an incremental conductance algorithm is used and this maximum power is fed to the grid via three-level VSC. The use of single stage system with three level VSC offers the advantage of low switching losses and the operation at high voltages and high power which results in enhancement of power quality in the proposed system. Simulated results validate the design and control algorithm under steady state and dynamic conditions.
Dynamics of IGBT based PWM Converter A Case Study
Directory of Open Access Journals (Sweden)
Vijay Shukla
2012-04-01
Full Text Available Optimizing the efficiency and dynamics of power converters is a critical tradeoff in power electronics. The increase of switching frequency can improve the dynamics of power converters, but theefficiency may be degraded as well as the switching losses. As power semiconductor devices like diodes, MOSFETS, IGBTs, Thyristors, BJTs have their own characterstics and dynamic responses. It is desired toanalyze and observe the dynamics of different semiconductor devices before they actually employed in the model. Inclusion of different PWM techniques help in the removal of power line interferences like harmonic losses, unwanted ripples, chopped frequencies, spikes. In this paper, we have studied and analyzed the dynamics of IGBT based PWM converter with subjected to different conditions like transient state, steady state feeding the RLC load. Snubber circuits are used to reduce the switching losses. The IGBT based PWM converter reflects the better dynamics with improved efficiency and reduced harmonics as compared to some other power semiconductor devices when FFT is performed and subjected to standard parameterized RLC load understeady state and transient analysis.
Parametric algorithms for frequency estimation in PWM converter systems
Energy Technology Data Exchange (ETDEWEB)
Lobos, T.; Hejke, I.; Rezmer, J.; Sikorski, T.; Kostyla, P. [Dept. of Electrical Engineering, Wroclaw University of Technology, Wyb. Wyspianskiego 27, 50-370 Wroclaw (Poland)
2009-11-15
Proper estimation of voltage parameters has a significant meaning for power converters control systems. One of the measured parameter, directly associated with control process, is frequency of the basic voltage component at the converter output. Unfortunately, power converters generate a wide spectrum of harmonics as well as interharmonics, that makes difficulties in estimation this frequency. Measurement carried out in industrial applications exhibits complex nature of investigated signals often corrupted by resonances or overvoltages phenomena. It entails searching a new digital algorithms for frequency measurement. This work presents algorithm using modification of high-resolution Prony method connected with digital filtering. The investigations was based on simulations and real measured signals recorded in two different commercial PWM converters. Obtained results indicate accuracy of the method as well as its fast response. (author)
Single Phase Bidirectional PWM Converter for Microgrid System
Directory of Open Access Journals (Sweden)
C.Kalavalli
2013-06-01
Full Text Available Smart grid is a newly flourishing research area because of its viable applications and expected to address the drawback of existing grid. Microgrids are the part of the Smart grid and they are designed to supply electricity for a small community such as residential areas, universities or industrial sites. Power electronics plays a vital role for connecting the renewable energy sources to Microgrid system. This paper deals the Microgrid connected single phase Bidirectional PWM converter which operates in Rectification and Inverting mode. This converter helps to connect renewable energy sources to loads as well as excess power are given to power grid. Double Loop PID control technique is used for controlling the converter for both modes. The designed Converter is simulated in MATLAB/Simulink software and results are verified using the Hardware.
Power angle control of grid-connected voltage source converter in a wind energy application
Energy Technology Data Exchange (ETDEWEB)
Svensson, Jan [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Electric Power Engineering
1995-12-31
In this thesis, the connection of a voltage source converter to the grid in a wind energy application is examined. The possibility of using a cheap control system without grid current measurements, is investigated. The control method is based on controlling the voltage angle of the inverter, which governs the active power flow. The highest frequency of the power variation, coming from wind turbine, is approx. 5 Hz. Since the proposed control method easily can handle such power variations it is very well suited for wind turbine applications. The characteristics of the system depend on the DC-link capacitor, the grid filter inductance and resistance. Large values of the resistance damp the system well but increase the energy losses. A high inductance leads to a reduced harmonic level on the grid but makes the system slower. By using feed-forward of the generator/rectifier current signal, the performance is increased compared to an ordinary PI-control. Combining the Linear Quadratic (LQ) control method with Kalman filtered input signals, a robust control method with a good performance is obtained. The LQ controller controls both the phase displacement angle and the modulation index, resulting in higher bandwidth, and the typical power angle resonance at the grid frequency disappears. 22 refs, 109 figs, 14 tabs
Effect of embedded voltage source converter on power system oscillation damping
Institute of Scientific and Technical Information of China (English)
R; DUNN
2010-01-01
This paper presents the damping torque analysis of power system oscillation stability as affected by the dynamic and control functions of an embedded voltage source converter(VSC).The objective of the study is to explain why and how the dynamic and basic control functions of the embedded VSC,ac and dc voltage regulation,provide damping to power system oscillations.The most important conclusion obtained in the paper is that both the dynamics and the dc voltage control of the VSC contribute a variable damping torque,which can be positive or negative,at different levels of system load conditions.More positive damping torque can be provided by the VSC at a heavier load condition.There exists a point of system load condition where the VSC provides no damping torque to power system oscillation hence dose not impose any influence on power system oscillation stability.The VSC studied in the paper can be the power-electronics-based interface of various FACTS(flexible ac transmission systems) devices,energy storage systems and renewable power generation units,although the focus of the discussion presented in this paper is the effect of the dynamics and basic control functions of the VSC themselves on power system oscillation damping.To demonstrate the analytical conclusions obtained in the paper,results of eigenvalue computation and nonlinear simulation of an example power system with STATCOM(static synchronous compensator) are given.
Improved Passive-Damped LCL Filter to Enhance Stability in Grid-Connected Voltage-Source Converters
DEFF Research Database (Denmark)
Beres, Remus Narcis; Wang, Xiongfei; Blaabjerg, Frede;
2015-01-01
This paper proposes an improved passive-damped LCL filter to be used as interface between the grid-connected voltage-source converters and the utility grid. The proposed filter replaces the LCL filter capacitor with a traditional C-type filter with the resonant circuit tuned in such a way that sw...
Apparatus and method for heat-run test on high-power PWM converters with low energy expenditure
Indian Academy of Sciences (India)
J S Siva Prasad; G Narayanan
2013-06-01
Before installation, a voltage source converter is usually subjected to heat-run test to verify its thermal design and performance under load. For heat-run test, the converter needs to be operated at rated voltage and rated current for a substantial length of time. Hence, such tests consume huge amount of energy in case of high-power converters. Also, the capacities of the source and loads available in the research and development (R & D) centre or the production facility could be inadequate to conduct such tests. This paper proposes a method to conduct heat-run tests on highpower, pulse width modulated (PWM) converters with low energy consumption. The experimental set-up consists of the converter under test and another converter (of similar or higher rating), both connected in parallel on the ac side and open on the dc side. Vector-control or synchronous reference frame control is employed to control the converters such that one draws certain amount of reactive power and the other supplies the same; only the system losses are drawn from the mains. The performance of the controller is validated through simulation and experiments. Experimental results, pertaining to heat-run tests on a high-power PWM converter, are presented at power levels of 25 kVA to 150 kVA.
Advanced power electronics converters PWM converters processing AC voltages
dos Santos, Euzeli
2014-01-01
This book covers power electronics, in depth, by presenting the basic principles and application details, which can be used both as a textbook and reference book. Introduces a new method to present power electronics converters called Power Blocks Geometry. Applicable for courses focusing on power electronics, power electronics converters, and advanced power converters. Offers a comprehensive set of simulation results to help understand the circuits presented throughout the book
Integrated PWM converter/inverter system feeding three-phase induction motor
Energy Technology Data Exchange (ETDEWEB)
Bayoumi, E.
2001-07-01
The integrated PWM converter/inverter system has the capability of unity power factor, sinusoidal supply current, bi-directional power capabilities and constant dc link voltage. Also, it has the ability to minimize the dc link capacitance. The integrated PWM converter/inverter fed three-phase induction motor consists of two identical PWM converters. One is used to serve as power regulator with unity power factor and constant dc voltage bus, while the other serve as inverter for the induction motor drive. By using the synchronous rotating-frame the current controllers in both the input and the output of the integrated system are characterized by fast current response and low harmonic distortion. The dc link is the intermediate stage between the PWM converter and the PWM inverter. It mainly consists of aluminium electrolytic capacitors, which are normally installed in the system as the energy storage element, but in some applications, such as high power voltage motor drives, the electrolytic capacitor has several drawbacks from the viewpoints of size, weight, cost and reliability. Due to continuous outgassing, the properties of the electrolytic capacitor deteriorate gradually (as time goes by). Hence, the capacitor is the major factor limiting the lifetime of the inverter systems. The aim of this work is to reduce the dc link capacitor size, as it means reduction of the cost and the volume of the converter/inverter systems. The work consists of 8 chapters: Chapter one illustrate the historical overview for the ac/dc/ac fed induction motor drive systems. It describes the benefits of the integrated PWM converter/inverter fed induction motor drive. It classified the integrated PWM converter/inverter systems into two types independent and dependent systems. It demonstrates some ideas for the control algorithms of these types of integrated systems. Chapter two introduces the mathematical model for the PWM converter. It explains the space vector PWM (SVPWM) method for
Integrated modeling and control of a PEM fuel cell power system with a PWM DC/DC converter
Energy Technology Data Exchange (ETDEWEB)
Choe, Song-Yul; Ahn, Jong-Woo [Mechanical Engineering Department, Auburn University, Auburn, AL 36848 (United States); Lee, Jung-Gi [Electrical Engineering Department, Pohang University of Science and Technology, Pohang (Korea); Baek, Soo-Hyun [Electrical Engineering Department, Dong-guk University, Seoul (Korea)
2007-02-10
A fuel cell powered system is regarded as a high current and low voltage source. To boost the output voltage of a fuel cell, a DC/DC converter is employed. Since these two systems show different dynamics, they need to be coordinated to meet the demand of a load. This paper proposes models for the two systems with associated controls, which take into account a PEM fuel cell stack with air supply and thermal systems, and a PWM DC/DC converter. The integrated simulation facilitates optimization of the power control strategy, and analyses of interrelated effects between the electric load and the temperature of cell components. In addition, the results show that the proposed power control can coordinate the two sources with improved dynamics and efficiency at a given dynamic load. (author)
Electrical Discharge Machining Flyback Converter using UC3842 Current Mode PWM Controller
Directory of Open Access Journals (Sweden)
Nazriah Mahmud
2014-10-01
Full Text Available This paper presents a current mode Pulse Width Modulation (PWM controlled Flyback converter using UC3842 for Electrical Discharge Machining current generator control circuit. Circuit simplicity and high efficiency can be achieved by a Flyback converter with current mode PWM controller. The behaviors of the system's operation is analyzed and discussed by varying the load resistance. Matlab sofware is used to simulate the Flyback converter where a prototype has been built and tested to verify it's performance.
Okedu, Kenneth Eloghene; Muyeen, S. M.; Takahashi, Rion; Tamura, Junji
Recent wind farm grid codes require wind generators to ride through voltage sags, which means that normal power production should be re-initiated once the nominal grid voltage is recovered. However, fixed speed wind turbine generator system using induction generator (IG) has the stability problem similar to the step-out phenomenon of a synchronous generator. On the other hand, doubly fed induction generator (DFIG) can control its real and reactive powers independently while being operated in variable speed mode. This paper proposes a new control strategy using DFIGs for stabilizing a wind farm composed of DFIGs and IGs, without incorporating additional FACTS devices. A new current controlled voltage source converter (CC-VSC) scheme is proposed to control the converters of DFIG and the performance is verified by comparing the results with those of voltage controlled voltage source converter (VC-VSC) scheme. Another salient feature of this study is to reduce the number of proportionate integral (PI) controllers used in the rotor side converter without degrading dynamic and transient performances. Moreover, DC-link protection scheme during grid fault can be omitted in the proposed scheme which reduces overall cost of the system. Extensive simulation analyses by using PSCAD/EMTDC are carried out to clarify the effectiveness of the proposed CC-VSC based control scheme of DFIGs.
Soft-switching PWM full-bridge converters topologies, control, and design
Ruan, Xinbo
2014-01-01
Soft-switching PWM full-bridge converters have been widely used in medium-to-high power dc-dc conversions for topological simplicity, easy control and high efficiency. Early works on soft-switching PWM full-bridge converter by many researchers included various topologies and modulation strategies. However, these works were scattered, and the relationship among these topologies and modulation strategies had not been revealed. This book intends to describe systematically the soft-switching techniques for pulse-width modulation (PWM) full-bridge converters, including the topologies, control and
Phase-lock loop of Grid-connected Voltage Source Converter under non-ideal grid condition
DEFF Research Database (Denmark)
Wang, Haojie; Sun, Hai; Han, Minxiao;
2015-01-01
phase information cannot be accurately tracked. Based on analysis of the cause of double-frequency ripple when unbalance exists in main grid, a phase-locked loop (PLL) detection technique is proposed. Under the conditions of unsymmetrical system voltage, varying system frequency, single-phase system......It is a normal practice that the DC micro-grid is connected to AC main grid through Grid-connected Voltage Source Converter (G-VSC) for voltage support. Accurate control of DC micro-grid voltage is difficult for G-VSC under unbalanced grid condition as the fundamental positive-sequence component...
Grid-Current-Feedback Active Damping for LCL Resonance in Grid-Connected Voltage-Source Converters
Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang
2016-01-01
This paper investigates active damping of LCL-filter resonance in a grid-connected voltage-source converter with only grid-current feedback control. Basic analysis in the s-domain shows that the proposed damping technique with a negative high-pass filter along its damping path is equivalent to adding a virtual impedance across the grid-side inductance. This added impedance is more precisely represented by a series RL branch in parallel with a negative inductance. The negative inductance helps...
DEFF Research Database (Denmark)
Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang
2014-01-01
This paper addresses the interaction between harmonic resonant controllers and active damping of LCL resonance in voltage source converters. A virtual series R-C damper in parallel with the filter capacitor is proposed with the capacitor current feedback loop. The phase lag resulting from the dig...... crossover frequency defined by the proportional gain of current controller. This is of particular interest for high-performance active harmonic filtering applications and low-pulse-ratio converters. Case studies in experiments validate the theoretical analysis.......This paper addresses the interaction between harmonic resonant controllers and active damping of LCL resonance in voltage source converters. A virtual series R-C damper in parallel with the filter capacitor is proposed with the capacitor current feedback loop. The phase lag resulting from...... the digital computation and modulation delays is thus compensated by the virtual capacitor. The frequency region that allows using resonant controllers is then identified with the virtual damper. It reveals that the upper frequency limit of harmonic resonant controllers can be increased above the gain...
Institute of Scientific and Technical Information of China (English)
彭一芯; 魏建勋; 黄辉先; 方鑫; 陆建龙
2015-01-01
For the problem that the system input parameters exists disturbances when the traditional sliding-mode varia-ble-structure control(SMVSC)is applied to the three-phase voltage source PWM rectifier,an online solution that sliding-mode variable-structure control base on improved PID neural network design was presented in this paper,taking three pa-rameters of PID as neurons of neural network in the hidden layer and considering that PID algorithm is of fast response,no static error and the online self-learning ability of neural network,the PID algorithm and neural network is combined to modi-fy the sliding approaching rate parameter in real-time,thus the time of system state into the sliding surface and jitter is re-duced.Through improving the selected value function,the algorithm cannot fall into local minimum and the global optimal solution is approached;also,the overall stability of the system is analyzed.Finally into simulation and experimental valida-tion research,show that the method possesses smaller shake and preferable dynamic response.%针对传统滑模变结构控制在三相电压型 PWM 整流器中应用时参数摄动所引起的抖动现象，提出一种改进 PID 神经网络的滑模变结构在线控制方法，将 PID 三个参数作为神经网络隐藏层的神经元，利用 PID 算法响应快、无静差的特点以及神经网络的在线自学习能力，实时对滑模趋近律参数进行修改，从而缩短系统状态进入滑模面的时间并减小抖动。对选取的价值函数进行改进，使算法不会陷入局部最优而逼近全局最优解，并对系统的全局稳定性进行分析。通过仿真和实验验证，结果表明该方法能使系统全局稳定，抖动有明显削弱且具有更好的动态响应。
在线自适应PWM死区消除方法%Online Adaptive Dead-Time Elimination Method for PWM Voltage Source Inverters
Institute of Scientific and Technical Information of China (English)
杨波; 吴建德; 李武华; 何湘宁
2011-01-01
A novel online adaptive dead-time elimination method is presented in this paper for PWM voltage source inverters,based on the analysis of dead-time effects and the principle of dead-time elimination.Tracking the load change on-line and determining dynamically the current direction,the zero current zone and the non zero current zone of the output inductor are precisely distinguished and the optimal width of the zero current zone is adaptively calculated.Furthermore,the dead-time effects are completely eliminated in the whole sinusoidal modulation cycle.In comparison with traditional dead-time compensation and elimination methods,the proposed method can significantly restrain the output distortion in the zero current zone and reduce the low-frequency harmonic contents and THD.The simulation and experimental results demonstrate the validity and practicability of the proposed method.%通过对死区效应原理和死区消除原则的分析,提出一种在线自适应的PWM死区消除方法。该方法通过在线跟踪负载变化,自适应地计算出最优的电感电流过零区域宽度,以精确实现电流过零区域和电流非过零区域中死区效应的分别消除,从而在整个正弦调制周期内达到最佳的死区消除效果。与传统的死区消除和补偿方法相比,该方法对电流过零处电压畸变的抑制效果尤为明显,能有效地降低输出电压低次谐波含量,使THD明显减小。仿真和实验结果证明了该死区消除方法的有效性和实用性。
High Frequency Soft Switching Of PWM Boost Converter Using Auxiliary Resonant Circuit
Directory of Open Access Journals (Sweden)
C. P. Sai Kiran
2014-10-01
Full Text Available This thesis presents High frequency Soft Switching DC-DC boost Converter. The circuit consists of a general Boost Converter with an additional resonant circuit which has a switch, inductor, capacitor and a diode.In general Boost Converter circuits have snubber circuits where switching losses are dissipated in external passive resistors; which is known as hard switching. As the switching frequency of PWM converters is increased its switching losses and conduction losses also increases. This restricts the use of PWM technique. New Zero Voltage Transition-Zero Current Transition (ZVT-ZCT PWM converter equipped with the snubber provides the most desirable features of both ZVT and ZCT converters presented previously. Moreover all semiconductors devices operate with soft switching and hence losses are reduced.
Datta, Aniket; Narayanan, G.
2016-12-01
Insulated gate bipolar transistor (IGBT) based voltage source converters use copper plates with insulating sheets in between them (sandwich bus-bar arrangement) for connecting the different device terminals in the power circuit. In such converters, the parasitic inductances in the power circuit are crucial as they cause overvoltage spikes across the device. Also, the parasitics affect the current sharing between IGBTs when they are connected in parallel in high power converters. The conduction path through plates and fasteners in the bus-bar assembly is three-dimensional and quite complex, making analytical evaluation of the stray inductance quite challenging. The first objective here is to present a simple experimental setup and experimental procedure, which are convenient for power electronic engineers, to measure the bus-bar inductance. The next objective is to carry out experimental studies on the inductances offered by different components and sub-assemblies in a bus-bar assembly. This includes evaluation of inductances of the different conduction paths in typical bus-bar plates. The third objective is to experimentally evaluate the parasitic inductances in the bus-bar assembly of a commercial 250 kVA high power converter. Each leg of this converter consists of two 300 A/1200 V IGBTs connected in parallel. The effective inductance seen by the individual device modules are determined experimentally.
DEFF Research Database (Denmark)
Zhang, Chi; Dragicevic, Tomislav; Vasquez, Juan Carlos;
2014-01-01
LCL filters play an important role in grid-connected converters when trying to reduce switching-frequency ripple currents injected into the grid. Besides, their small size and low cost make them attractive for many practical applications. However, the LCL filter is a third-order system, which...... presents a resonance peak frequency. Oscillation will occur in the control loop in high frequency ranges, especially in current loop in double-loops controlled converters. In order to solve this, many strategies have been proposed to damp resonance, including passive and active methods. This paper makes...
Synchronization of the distributed PWM carrier waves for modular multilevel converters
DEFF Research Database (Denmark)
Burlacu, Paul Dan; Mathe, Laszlo; Teodorescu, Remus
2014-01-01
The half-bridge modular multilevel converter has proven itself to be a suitable solution for HVDC application. In order to achieve high modularity and fault tolerance, distributed control strategy is one possible solution and is discussed in this paper. When distributed control strategy is used, ...... the PWM outputs of each sub-module increasing the total harmonic distortion of the output voltage. This paper presents a solution to synchronize the PWM outputs of the MMC submodules using EtherCAT communication protocol focusing on phase shifted PWM modulation technique....
An active trap filter for high-power voltage source converters
DEFF Research Database (Denmark)
Bai, Haofeng; Wang, Xiongfei; Loh, Poh Chiang;
2015-01-01
This paper proposes a power electronic based device to actively trap the switching current ripples for highpower converters. Control principle and system design of the active trap filter are discussed first. Comparisons of the active trap filter with LCL and LLCL filters are then carried out...... in time-domain simulations and experimental tests. The results demonstrate that the active trap filter not only provides more controllability and flexibility than the passive filters, but also mitigates the adverse effects of parameter shifts on harmonic filtering performance of passive filters....
Elimination of output voltage oscillations in DC-DC converter using PWM with PI controller
Directory of Open Access Journals (Sweden)
Sreenivasappa Veeranna Bhupasandra
2010-01-01
Full Text Available In this paper the SIMULINK model of a PWM controlled DC-DC converter is modeled using switching function concept to control the speed of the DC motor. The presence of the voltage oscillation cycles due to higher switching frequency in the DC-DC converter is identified. The effect of these oscillations on the output voltage of the converter, Armature current, Developed torque and Speed of the DC motor is analyzed. In order to minimize the oscillation cycles the PI controller is proposed in the PWM controller.
The efficiency of three-level Active NPC converter for different PWM strategies
DEFF Research Database (Denmark)
Floricau, D.; Gateau, G.; Leredde, A.;
2009-01-01
The efficiency of power conversion is an important factor to design static converters. The paper is focused on the calculus of total losses of 3L-NPC and 3L-Active-NPC converters for different PWM strategies. The calculus was made in the most critical operating points when certain switches have...
New PWM method and commutation strategy for HF-link converters for fuel cells and photovoltaics
DEFF Research Database (Denmark)
Ljusev, Petar; Andersen, Michael Andreas E.
2005-01-01
This paper presents a new PWM method and commutation strategy for HF-link converters, which leads to safe commutation of the load current in the output bidirectional bridge. The proposed implementation is independent of the particular HF-link converter topology and bidirectional switch selection...
DEFF Research Database (Denmark)
Panfilov, Dmitry; Husev, Oleksandr; Blaabjerg, Frede
2016-01-01
This study compares a three-phase three-level voltage source inverter with an intermediate dc-dc boost converter and a quasi-Z-source inverter in terms of passive elements values and dimensions, semiconductor stresses, and overall efficiency. A comparative analysis was conducted with relative par...
Institute of Scientific and Technical Information of China (English)
毛鸿; 吴兆麟; 王毅; 刘树林
2001-01-01
三相电压型PWM整流器有间接电流控制和直接电流控制两种方式，两种控制方式各有优点。根据三相电压型PWM整流器的高频动态数学模型，提出了基于开关函数检测的无电流传感器控制策略。该控制策略兼有间接电流控制结构简单，成本低和直接电流控制动态响应速度快、限流容易、控制精度高等优点。实验结果验证了控制策略的可行性。%There are two basic control schemes for three-phase voltage-source PWM rectifier: the direct current control and indirect current control. The direct current control scheme achieves better dynamic and steady state performance, but its control cost is much higher than the indirect current control. Based on the dynamic high frequency mathematical model of three-phase voltage-source PWM rectifier, a novel sensorless current control strategy is presented for the first time, which is implemented by estimating the variables of the three-phase input current via other variables. The control strategy has super characters such as simple structure, low cost, good dynamic and steady state performance and ability to limit the input currents. A simple hardware implementation is proposed and the good experimental results are reported to confirm the quality of the presented strategy.
Soft Switching Full-Bridge PWM DC/DC Converter Using Secondary Snubber
Directory of Open Access Journals (Sweden)
Jaroslav Dudrik
2009-05-01
Full Text Available A novel full-bridge PWM DC/DCconverter with controlled secondary side rectifier usingsecondary snubber is presented in this paper.Limitation of the circulating current as well as softswitching for all power switches of the inverter isachieved for full load range from no-load to shortcircuit by using controlled rectifier and snubber on thesecondary side. Phase shift PWM control strategy isused for the converter. The principle of operation isexplained and analyzed and the experimental resultson a 1kW, 50 kHz laboratory model of the converterare presented.
Performance Comparison of Phase Shifted PWM and Sorting Method for Modular Multilevel Converters
DEFF Research Database (Denmark)
Haddioui, Marcos Rejas; Máthé, Lászlo; Burlacu, Paul Dan;
2015-01-01
Modular Multilevel Converters (MMC) are the solution of preference in HVDC applications due to modularity, scalability, low losses and low filtering requirement. Carrier-based (PWM) and carrier-less (nearest level control) modulation can be applied. By using advanced sorting methods focusing...... on keeping the capacitor voltage ripple under some limit, unnecessary switching events are eliminated leading to reduced switching losses. This paper presents a comparison between the steady-state performances in terms of output voltage THD and equivalent switching frequency of the Phase Shifted Carrier PWM...
电压型PWM逆变器控制技术的改进%The Improvement of Control Technology for Voltage Source PWM Inverter
Institute of Scientific and Technical Information of China (English)
李雪龙; 周渊深; 李少鹏
2013-01-01
For the purpose of enhancing PWM inverter’s dynamic decoupling effects in current control loop, this paper apply IMC method to PWM inverter which is based on double (voltage and current) close-loop control. In addition, a kind of AC current regulator is designed, and its compensation signal as well as DC correction signal are together to determine the output of control, which reduces fluctuations at the DC side. In this paper, the waveforms via Simulink of the advanced scheme are presented, and the simulation results confirm the validity of the mentioned strategy.%基于电压型PWM逆变器电压电流双闭环控制框架，针对电流环的交叉耦合问题，采用内模解耦（IMC）方法以提高PWM逆变器动态过程中的解耦效果。除此以外，设计了交流电流调节器，其补偿信号与直流电流调节器的校正信号相加共同产生控制量的输出，以降低直流侧电压的波动性。给出了整体改进方案的Simulink仿真波形，结果证明了改进方案的可行性和有效性。
Institute of Scientific and Technical Information of China (English)
杨达亮; 卢子广; 杭乃善; 李国进
2011-01-01
建立三相电压型脉宽调制（pulse width modulation，PWM）整流器在不同坐标系下的数学模型，分析直接功率控制（direct power control，DPC）的工作原理。针对直接功率控制中开关频率变化问题，通过对PWM整流器瞬时功率分析推导，提出一种内环直接采用电流控制的新型准定频直接功率控制策略。仿真验证了算法的可行性。采用PM300DVAl20智能功率模块，设计50kVA的三相电压型PWM整流器控制实验，在10kHz、5us的开关频率下获得良好的实验结果。实验结果表明，所提方法实现单位功率因数运行，与现行的DPC—SVM定频控制方法相比，具有更好的动静态响应性能。%This paper established the three-phase voltage-source pulse width modulation （PWM） rectifier mathematical models in different coordinate systems and analyzed the principle of direct power control （DPC）. To alleviate the problem of variable switching frequency, a novel quasi DPC control strategy with current loop was represented through the analysis of PWM rectifier instantaneous power. The novel control strategy was proved feasible by the Matlab/Simulink simulation results. The 50kVA three-phase voltage-source PWM rectifier control experiment system was designed using PM300DVA120 intelligent power module （IPM）, the excellent experiment results were given at the 10kHz switching frequency with 5μs dead time. The experimental results indicate that the PWM rectifier system achieves unity power factor operation and has better performance of dynamic and static response compared to the present space vector modulation （SVM） DPC fixed-frequency control method.
Step-by-Step Design Procedure for a Grid-Connected Three-Phase PWM Voltage Source Converter,
DEFF Research Database (Denmark)
Liserre, Marco; Blaabjerg, Frede; Aquila, Antonio Dell
2004-01-01
controllers. In this paper a step-by-step design procedure, taking into account all these elements, is proposed and validated through the tests on an experimental prototype. The reported results are particularly relevant to evaluate the influence on the grid current harmonic content of the grid sensor...
DEFF Research Database (Denmark)
Xiao, Lei; Huang, Shoudao; Lu, Kaiyuan
2013-01-01
Unbalanced grid voltage will cause large dc-bus voltage ripple and introduce high harmonic current components on the grid side. This will severely threaten the safety of the grid-connected voltage source converter (VSC) and consequently, affect the healthy operation condition of the load. In this......Unbalanced grid voltage will cause large dc-bus voltage ripple and introduce high harmonic current components on the grid side. This will severely threaten the safety of the grid-connected voltage source converter (VSC) and consequently, affect the healthy operation condition of the load....... In this study, a new proportional-integral-resonant (PI-RES) controller-based, space vector modulated direct power control topology is proposed to suppress the dc-bus voltage ripple and in the same time, controlling effectively the instantaneous power of the VSC. A special ac reactive power reference component...
PWM Technique for Non-Isolated Three-Phase Buck-Boost PFC Converter
Morizane, Toshimitsu; Shimomori, Wataru; Taniguchi, Katsunori; Kimura, Noriyuki; Ogawa, Masanori
The buck-boost power factor corrected (PFC) converter has the wide range of the dc output voltage. A new non-isolated three-phase hard-switching and a soft-switching buck-boost PFC converter are proposed. Removing the three-phase transformer from the converters makes their size more compact and their costs lower. In addition, the new control method based on the PWM technique is proposed in this paper to achieve the high power factor. Complete soft-switching is also achieved under the discontinuous current mode (DCM) operation.
A digitally controlled PWM/PSM dual-mode DC/DC converter
Institute of Scientific and Technical Information of China (English)
Zhen Shaowei; Zhang Bo; Luo Ping; Hou Sijian; Ye Jingxin; Ma Xiao
2011-01-01
A digitally controlled pulse width modulation/pulse skip modulation (PWM/PSM) dual-mode buck DC/DC converter is proposed.Its operation mode can be automatically chosen as continuous conduction mode (CCM) or discontinuous conduction mode (DCM).The converter works in PSM at DCM and in 2 MHz PWM at CCM.Switching loss is reduced at a light load by skipping cycles.Thus high conversion efficiency is realized in a wide load current.The implementations of PWM control blocks,such as the ADC,the digital pulse width modulator (DPWM) and the loop compensator,and PSM control blocks are described in detail.The parameters of the loop compensator can be programmed for different external component values and switching frequencies,which is much more flexible than its analog rivals.The chip is manufactured in 0.13 μm CMOS technology and the chip area is 1.21 mm2.Experimental results show that the conversion efficiency is high,being 90% at 200 mA and 67% at 20 mA.Meanwhile,the measured load step response shows that the proposed dual-mode converter has good stability.
Calderone, Luigi; Pinola, Licia; Varoli, Vincenzo
1992-04-01
The paper describes an analytical procedure to optimize the feed-forward compensation for any PWM dc/dc converters. The aims of achieving zero dc audiosusceptibility was found to be possible for the buck, buck-boost, Cuk, and SEPIC cells; for the boost converter, however, only nonoptimal compensation is feasible. Rules for the design of PWM controllers and procedures for the evaluation of the hardware-introduced errors are discussed. A PWM controller implementing the optimal feed-forward compensation for buck-boost, Cuk, and SEPIC cells is described and fully experimentally characterized.
Closed loop control of ZVS half bridge DC-DC converter with DCS PWM Control
Directory of Open Access Journals (Sweden)
JANAPATI SIVAVARA PRASAD
2012-10-01
Full Text Available
The main drawback of the conventional symmetric control is that both primary switches in the converter operate at hard switching condition. Moreover, during the off-time period of two switches, the oscillation between the transformer leakage inductance and junction capacitance of the switches results in energy dissipation and electromagnetic interference (EMI emissions due to reverse recovery of MOSFETs body diodes. The asymmetric (complementary control was proposed to achieve ZVS operation for HB switches. However, asymmetric stresses distribution on the corresponding components may occur due to the asymmetric duty cycle distribution for the two primary switches. A new control scheme, to be known as duty-cycle shifted PWM (DCS PWM control, is proposed and applied to the conventional HB dc–dc converters to achieve ZVS for both the switches without adding extra components and without adding asymmetric penalties of the complementary control. The concept of this new control scheme is shifting one of the two symmetric PWM driving signals close to the other, such that ZVS may be achieved for the lagging switch due to the shortened resonant interval. Moreover, based on the DCS PWM control, a new half-bridge topology is proposed to achieve ZVS for both the main switches and auxiliary switch by adding an auxiliary switch and diode in the proposed half bridge. ZVS for the switch is achieved by utilizing the energy trapped in the leakage inductance. There are two control schemes. One is open loop and the other is closed loop. In open loop scheme, the given dc-dc converter is operating under disturbance. This disturbance effect is eliminated in closed loop scheme.
Simulation on Soft-Switching PWM Converter with High Power Factor
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
A new PWM converter based on soft-switching is introduced. The converter uses a minimum number of devices, and requires less switching operations than conventional techniques. Switching is realized solely in a ZVS (zero voltage switching) mode,therefore the loss is reduced and EMI (electromagnetic interference) is suppressed. The paper analyzes the operation of ZVS, and discusses the methods for maintaining a unit power factor and constant DC voltage. Changing the modulation index M and the phase angle θ keeps the input current in phase with the voltage. It also keeps the current sinusoidal, and ensures a constant output voltage.
DEFF Research Database (Denmark)
Zhang, Gang; Yang, Yongheng; Iannuzzo, Francesco
2016-01-01
of the 3L-ANPC topology. This paper presents a novel loss balancing modulation strategy - Splitting Switching Loss Distribution PWM (SSLD-PWM) strategy to achieve more even loss distribution in the 3L-ANPC converter. Basically, in the proposed PWM strategy, the switching-on losses and switching-off losses...
Institute of Scientific and Technical Information of China (English)
罗德荣; 姬小豪; 黄晟; 廖武
2014-01-01
Mathematical modeling of voltage source PWM filter is conducted and a predictive power model under two-phase rest frame is established, on this basis an optimal model predictive direct power control (MPDPC) strategy is proposed. In the proposed control strategy the voltage vector in power supply system is taken as the basic control vector and utilizing power directive model and minimum power error principle the formula of objective control voltage vector is obtained, then combining with space vector PWM modulation(SVPWM) the model predictive direct power control is implemented. Meanwhile, considering the step delay in actual control systems a delay compensation scheme is designed. Besides, the repetitive control is led in to optimize the active and reactive power in each sampling cycle. The feasibility of the proposed control method is validated by results of simulation and experiments.%对电压型PWM整流器进行了数学建模，然后在两相静止坐标系下建立了预测功率模型，在此基础上提出了优化的模型预测直接功率控制(model predictive direct power control，MPDPC)策略。该方法用电网电压矢量作为基本控制矢量，利用功率预测模型和功率误差最小原则，得出目标控制电压矢量公式，结合空间矢量脉宽调制实现模型预测功率控制。同时针对实际系统中的一步延迟设计了延时补偿方案。此外，在系统中引入重复控制对每个采样周期系统的有功、无功功率进行优化。仿真和实验验证了表明所提出的方法的可行性。
Advanced Control Strategy of Back-to-Back PWM Converters in PMSG Wind Power System
Directory of Open Access Journals (Sweden)
Tan Luong Van
2015-01-01
Full Text Available This paper proposes a control scheme of back-to-back PWM converters for the permanent magnet synchronous generator (PMSG wind turbine system. The DC-link voltage can be controlled at the machine-side converter (MSC, while the grid-side converter (GSC controls the grid active power for a maximum power point tracking (MPPT. At the grid fault condition, the DC-link voltage controller is designed using a feedback linearization (FL theory. For the MPPT, a proportional control loop is added to the torque control to reduce the influence of the inertia moment in the wind turbines, which can improve its dynamic performance. The validity of this control algorithm has been verified by the simulation of the 2-MW PMSG wind turbine system.
Directory of Open Access Journals (Sweden)
Rasoul Shalchi Alishah
2015-06-01
Full Text Available In recent, several numbers of multilevel inverter structures have been introduced that the numbers of circuit devices have been reduced. This paper introduces a new structure for multilevel inverter which can be used in high-power applications. The proposed topology is based on cascaded connection of basic units. This topology consists of minimum number of circuit components such as IGBT, gate driver circuit and antiparallel diode. For proposed topology, two methods are presented for determination of dc voltage sources values. Multi-carrier PWM method for 25-level proposed topology is used. Verification of the analytical results is done using MATLAB simulation.
Institute of Scientific and Technical Information of China (English)
李武云
2014-01-01
The improved space vector hysteresis control was introduced for the disadvantage of poor current tracking caused by the traditional control strategy in the three-phase voltage source PWM rectifier. The improved strategy choose the hysteresis loop width and the switch state through the judgment of the AC error current vector modulus, and the selection principle of the switch state was provided in order to reduce the switching losses. Final y, the simulation model was established under matlab/simulink to compare AC current quality between the traditional and the improved control strategies, the simulation results further demonstrated the superiority of the improved control scheme.%提出了一种改进的滞环空间矢量控制，用于解决三相电压型PWM整流器采用传统滞环空间矢量控制时，电流跟踪效果不佳的问题。改进后的控制策略通过对交流侧误差电流矢量模值大小判断后，选择滞环环宽和对应的开关状态，同时总结出最佳的开关状态选择原则，以最大限度地低开关损耗，提高系统响应速度。最后在matlab/simulink下建立系统的仿真模型，通过对改进前后两种控制策略下交流侧电流质量的对比，进一步验证了改进后控制策略的优越性。
A Study of Novel ZVZCT SoftSwitching PWM Boost Converters%新型ZVZCT软开关PWM Boost 变换器的研究
Institute of Scientific and Technical Information of China (English)
林国庆; 张冠生; 陈为; 黄是鹏
2000-01-01
The paper presents a novel ZVZCT softswitching PWM converter:the voltage and current waveforms of the transistor are laddershaped and stagger each other,and auxiliary switches are turned on and off under zero current.It is very attractive for high power application where IGBT is predomi nantly used as the power switches.Theoretical analysis,parameters selection,comp uter simulation,and experiment results are presented to explain the proposed sch eme.
DEFF Research Database (Denmark)
Teodorescu, Remus; Blaabjerg, Frede
2004-01-01
This paper is describing the recently introduced proportional-resonant (PR) controllers and their suitability for grid-connected converters current control. It is shown that the known shortcomings associated with PI controllers like steady - state error for single-phase converters and the need...... of decoupling for three-phase converters can be alleviated. Additionally, selective harmonic compensation is also possible with PR controllers. Suggested control-diagrams for three-phase grid converters and active filters are also presented. A practical application of PR current control for a photovoltaic (PV...
A PAC Based Current Feedforward Control for Three-Phase PWM Voltage-Type Converter
Institute of Scientific and Technical Information of China (English)
屈克庆; 陈国呈; 孙承波
2004-01-01
This paper presents a novel current feedforward control strategy for a three-phase pulse-width modulation (PWM) DC voltage-type converter based on phase and amplitude control (PAC). With right-angle triangle relation of phasors and principle of conservation of energy, a phasor adjustment method and the relevant low-frequency mathematical model of the system are analyzed in detail, both in rectification and regeneration modes for the converter, are discussed. For improving the traditional PAC dynamic performance, variable load current is detected indirectly by the change of the DC voltage, which is fed to the control system as an additional control variable to generate modulation index and phase angle. Also, the algorithm is derived and the system principle is introduced. Experimental results from a 3 kw laboratory device are included to demonstrate the effectiveness of the proposed control strategy.
Directory of Open Access Journals (Sweden)
Taizhou Bei
2014-01-01
Full Text Available Considering the disadvantages of the traditional high-gain DC-DC converter such as big size, high voltage stress of switches, and large input current ripple, a novel high-gain interleaved boost converter with coupled-inductor and switched-capacitor was proposed correspondingly and the operation principle together with the steady-state analysis of this converter was also described. Besides, a new control approach-dynamic sliding mode evolution PWM controller (DSME PWM for the novel topological converter based on both dynamic evolution and sliding mode control was also presented. From the simulation results and experimental validation the proposed converter can fulfill high-gain boost, low ripple of both the input current and the output voltage. Furthermore, MPPT technique can be also achieved in a short time by simulation. The efficiency and stability of the converter proposed in this paper can be improved.
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
This letter presents a multi-frequency proportional-resonant (MFPR) current controller developed for PWM voltage source converter (VSC) under the unbalanced supply voltage conditions. The delta operator is used in place of the shift operator for the implementation of MFPR by using a low-cost fixed-point DSP. The experimental results with an alternative control strategy validated the feasibility of the proposed MFPR current controller for the PWM VSC during voltage unbalance.
Bifurcation boundary conditions for current programmed PWM DC-DC converters at light loading
Fang, Chung-Chieh
2012-10-01
Three types of bifurcations (instabilities) in the PWM DC-DC converter at light loading under current mode control in continuous-conduction mode (CCM) or discontinuous-conduction mode (DCM) are analysed: saddle-node bifurcation (SNB) in CCM or DCM, border-collision bifurcation during the CCM-DCM transition, and period-doubling bifurcation in CCM. Different bifurcations occur in some particular loading ranges. Bifurcation boundary conditions separating stable regions from unstable regions in the parametric space are derived. A new methodology to analyse the SNB in the buck converter based on the peak inductor current is proposed. The same methodology is applied to analyse the other types of bifurcations and converters. In the buck converter, multiple stable/unstable CCM/DCM steady-state solutions may coexist. Possibility of multiple solutions deserves careful study, because an ignored solution may merge with a desired stable solution and make both disappear. Understanding of SNB can explain some sudden disappearances or jumps of steady-state solutions observed in switching converters.
A Review of Passive Power Filters for Three-Phase Grid-Connected Voltage-Source Converters
DEFF Research Database (Denmark)
Beres, Remus Narcis; Wang, Xiongfei; Liserre, Marco;
2016-01-01
with the utility grid are reviewed, and evaluated in terms of damping capability, stored energy in the passive components and power loss in the damping circuit. Additionally, the influences of different switching frequencies of power converters on the passive filter design are also discussed in the range of 1-15 k...
Energy Technology Data Exchange (ETDEWEB)
Leon, Andres E.; Solsona, Jorge A.; Busada, Claudio; Chiacchiarini, Hector [Instituto de Investigaciones en Ingenieria Electrica (IIIE) UNS-CONICET, Universidad Nacional del Sur, Av. Alem 1253, Bahia Blanca 8000 (Argentina); Valla, Maria Ines [Laboratorio de Electronica Industrial, Control e Instrumentacion (LEICI) and CONICET, Facultad de Ingenieria, Universidad Nacional de La Plata, La Plata 1900 (Argentina)
2009-08-15
In this paper a new control strategy for voltage-source converters (VSC) is introduced. The proposed strategy consists of a nonlinear feedback controller based on feedback linearization plus a feedforward compensation of the estimated load current. In our proposal an energy function and the direct-axis current are considered as outputs, in order to avoid the internal dynamics. In this way, a full linearization is obtained via nonlinear transformation and feedback. An estimate of the load current is feedforwarded to improve the performance of the whole system and to diminish the capacitor size. This estimation allows to obtain a more rugged and cheaper implementation. The estimate is calculated by using a nonlinear reduced-order observer. The proposal is validated through different tests. These tests include performance in presence of switching frequency, measurement filters delays, parameters uncertainties and disturbances in the input voltage. (author)
Institute of Scientific and Technical Information of China (English)
王恩德; 黄声华
2012-01-01
同步旋转d-q坐标系下的电压、电流双闭环控制，广泛应用于三相电压型PWM整流器。该方案结构简单，比较适合基于数字处理芯片的数字控制系统。由于交流侧电感工艺存在差异，且当电流很大电感饱和时，电感值也会有变化，实际控制系统往往忽略掉耦合项；而电压外环的非线性也使得控制系统的性能提升受到限制。提出一种新的电压电流双闭环控制策略，其中电流内环借鉴合成矢量的思想，提出同步旋转d-q坐标系下无电感￡参数的电流解耦控制方法：电压外环采用电压平方为控制量实现线性化的间接电压控制。仿真与实验结果均验证了所提方法的正确性和有效性。%The double closed loop control strategy, which is composed of inner current loop and outer voltage loop in the d-q synchronous frame, is a relatively common control strategy of the three-phase voltage-sourced PWM rectifier. This strategy is suitable for the digital control system with the digital signal processor （DSP）, because of its simple structure. The decoupling part is often ignored without the exact value of the boost inductance. And the nonlinear outer voltage loop is also the limit to improve the control performance. This paper proposed a novel double closed loop control strategy, which consists of decoupling current controller without exact value of the boost inductance in d-q synchronous frame, and the outer voltage linear control strategy with the control amount of the square of the voltage. Both the simulation analysis and experimental results demonstrate the validity of the proposed method and the feasibility of the control strategy.
DEFF Research Database (Denmark)
Song, Kejian; Konstantinou, Georgios; Mingli, Wu
2017-01-01
AC electric locomotives that use a number of interleaved four-quadrant converters generate high-frequency switching harmonics which may stimulate certain resonances in traction power supply systems (TPSSs). A windowed selective harmonic elimination pulse-width modulation (SHE-PWM) method...
DEFF Research Database (Denmark)
Zhu, Jiebei; Guerrero, Josep M.; Hung, William;
2014-01-01
within a safe and pre-defined range. A theoretical treatment of the INEC algorithm and its implementation and integration within a conventional VSC control system are presented, and the impact on the total DC capacitance required within the MTDC network to ensure that DC voltages vary within...... an acceptable range are discussed. The proposed INEC scheme is validated using a Matlab/Simulink model under various changes in demand and in response to AC network faults. The model incorporates a multi-machine AC power system connected to a MTDC transmission system with multiple converter-interfaced nodes....... The effectiveness of the INEC in damping post-fault oscillations and in enhancing AC system frequency stability is also investigated. The system is shown to perform well and is attractive for providing a stable MTDC system that is capable of providing valuable support to the connected AC systems....
DEFF Research Database (Denmark)
Liu, Dong; Deng, Fujin; Chen, Zhe
2017-01-01
The capacitor current would be imbalanced under the conventional control strategy in the half-bridge three-level (HBTL) DC/DC converter due to the effect of the output inductance of the power supply and the input line inductance, which would affect the converter's reliability. This paper proposes...... a pulse-wide modulation (PWM) strategy composed of two operation modes for the HBTL DC/DC converter, which can realize the zero-voltage switching (ZVS) for the efficiency improvement. In addition, a capacitor current balancing control is proposed by alternating the two operation modes of the proposed ZVS...... PWM strategy, which can eliminate the current imbalance among the two input capacitors. Therefore, the proposed control strategy can improve the converter's performance and reliability in: 1) reducing the switching losses and noises of the power switches; 2) balancing the thermal stresses...
DEFF Research Database (Denmark)
Zhang, Zhe; Andersen, Michael A. E.
2013-01-01
This paper presents an isolated dual-input DC-DC converter with a PWM plus phase-shift control for fuel cell hybrid energy systems. The power switches are controlled by phase shifted PWM signals with a variable duty cycle, and thus the two input voltages as well as the output voltage can...
DEFF Research Database (Denmark)
Forouzesh, Mojtaba; Siwakoti, Yam Prasad; Blaabjerg, Frede
2016-01-01
Magnetically coupled Y-source impedance network is a newly proposed structure with versatile features intended for various power converter applications e.g. in the renewable energy technologies. The voltage gain of the Y-source impedance network rises exponentially as a function of turns ratio......, which is inherited from a special coupled inductor with three windings. Due to the importance of modeling in the converter design procedure, this paper is dedicated to dc and ac small signal modeling of the PWM Y-source converter. The derived transfer functions are presented in detail and have been...
Simple digital PWM and PSM controlled DC-DC boost converter for luminance-regulated WLED driver
Institute of Scientific and Technical Information of China (English)
LIU Xin; GUO Shu-xu; CHANG Yu-chun; ZHU Shun-dong; WANG Shuai
2009-01-01
This article presents a control strategy based on simple digital pulse-width modulation (DPWM) and pulse-skip modulation (PSM) for a DC-DC boost converter, to drive a luminance-regulated white light emitting diodes (WLEDs). The presented control strategy not only retains most of the advantages and flexibilities of traditional digital PWM, but also reduces complexity and cost. Based on analyzing the principle of the presented control strategy, the white light emitting diode (WLED) driver is designed and simulated using the 0.6 (m CMOS process. Simulation results of the boost converter show that the power efficiency is above 76% for a full load, with a peak efficiency of 88% when supply voltage varies from 2.7 V to 5.5 V. The control strategy overcomes low efficiency for PWM mode with light load.
Institute of Scientific and Technical Information of China (English)
YanfengCHEN; ShuishengQIU; 等
1999-01-01
An extension of characteristic equation analysis method to the stability analysis of equilibrium points for closed-loop PWM power switching converters is introduced based on equivalent small parameter method.The basic principle of the method is described in detail.The provided example shows that the method,incorporating with the system's state-plane trajectories,offers the advantages of both simplicity and practicality.
Sugimura, Hisayuki; Muraoka, Hidekazu; Hiraki, Eiji; Hirota, Izuo; Yasui, Kenji; Omori, Hideki; Lee, Hyun-Woo; Nakaoka, Mutsuo
In this paper, high frequency power converter without DC smoothing electrolytic capacitor filter link which convert the 100V/200Vrms and 60Hz single phase utility frequency AC power into a high frequency AC. This proposed high frequency AC power converter without electrolytic capacitor filter can operate under a principle of soft switching PWM based on a lossless capacitor snubber is proposed and demonstrated for consumer high frequency induction heating (IH). In particular, this high frequency power converter capable of producing a high frequency AC more than 20kHz is developed for consumer IH applications as hot water producer and steamer based on the specially designed spiral type IH-Dual Packs Heater (DPH), which includes the dual mode pulse modulation control scheme based on soft switching PWM for high output power setting and commercial frequency AC zero voltage soft switching pulse density modulation (PDM) for low output power settings. This developed high frequency power frequency converter using trench gate IGBTs is clarified on the basis of experimental and simulation results for its circuit operation of the utility frequency AC to high frequency AC frequency PWM power converter without the electrolytic capacitor bank DC filter link for the IH hot water and IH steamer. These IH appliances are based upon an innovative electromagnetic IH-DPH for fluid heating as heat exchanger in consumer pipeline. Finally, its power regulation characteristics, power conversion efficiency and harmonic current components characteristics including power factor in utility AC grid side are evaluated and discussed from an experimental point of view. The practical effectiveness of this utility frequency AC to high frequency AC soft switching high power frequency converter defined conveniently as high frequency soft switching cyclo-inverter is proved as one of the important products effective for next generation IH application all electricity power utilizations.
A novel five-level optimized carrier multilevel PWM quad-inverter six-phase AC drive
DEFF Research Database (Denmark)
Sanjeevikumar, P.; Blaabjerg, F.; Wheeler, Pat
2016-01-01
A novel single carrier pulse-width modulation (PWM) for a new quad-inverter configuration for multilevel six-phase asymmetrical open-winding ac converter is proposed in this article. Modularity of the circuit consist of four standard two-level voltage source inverters (VSIs) with slight modificat...
Alawasa, Khaled Mohammad
Voltage-source converters (VSCs) have gained widespread acceptance in modern power systems. The stability and dynamics of power systems involving these devices have recently become salient issues. In the small-signal sense, the dynamics of VSC-based systems is dictated by its incremental output impedance, which is formed by a combination of 'passive' circuit components and 'active' control elements. Control elements such as control parameters, control loops, and control topologies play a significant role in shaping the impedance profile. Depending on the control schemes and strategies used, VSC-based systems can exhibit different incremental impedance dynamics. As the control elements and dynamics are involved in the impedance structure, the frequency-dependent output impedance might have a negative real-part (i.e., a negative resistance). In the grid-connected mode, the negative resistance degrades the system damping and negatively impacts the stability. In high-voltage networks where high-power VSC-based systems are usually employed and where sub-synchronous dynamics usually exist, integrating large VSC-based systems might reduce the overall damping and results in unstable dynamics. The objectives of this thesis are to (1) investigate and analyze the output impedance properties under different control strategies and control functions, (2) identify and characterize the key contributors to the impedance and sub-synchronous damping profiles, and (3) propose mitigation techniques to minimize and eliminate the negative impact associated with integrating VSC-based systems into power systems. Different VSC configurations are considered in this thesis; in particular, the full-scale and partial-scale topologies (doubly fed-induction generators) are addressed. Additionally, the impedance and system damping profiles are studied under two different control strategies: the standard vector control strategy and the recently-developed power synchronization control strategy
随机PWM CCM Boost变换器非脆弱H∞控制%Non-fragile H∞ control for random PWM CCM Boost converter
Institute of Scientific and Technical Information of China (English)
冉华军; 张涛
2013-01-01
With two - state - Markov - chain random PWM scheme introduced into CCM Boost converter , the random discrete - time jumping model is established first. Then, non - fragile H∞ controller is derived on the basis of non - fragile H∞ control theory of stochastic jumping system. Finally, the simulation circuit is designed to check the validity of non - fragile H∞ controller on the Simulink platform. The results show that the controller designed in this paper has improved the EMI level of Boost converter with non - fragility to its parameters uncertainty, and the whole converter system is robust.%对CCM Boost变换器引入两模态马尔科夫链稳态期望平均脉宽固定的随机PWM策略,首先推导建立变换器的离散随机跳变模型,然后基于随机跳变系统非脆弱H∞控制理论为Boost变换器设计了非脆弱H∞控制器,最后在Simulink仿真平台上设计仿真电路进行验证.仿真结果表明,设计的控制器改善了Boost变换器的EMI品质,对控制器参数摄动表现出非脆弱性,整个变换器系统具有较好的鲁棒性.
Chen, Lei; Tang, Yuejin; Shi, Jing; Li, Zhi; Ren, Li; Cheng, Shijie
2010-02-01
The integrated voltage compensation type active superconducting fault current limiter (SFCL) is composed of three air-core superconducting transformers and a three-phase four-wire PWM converter. In order to realize the current-limiting characteristics of the integrated active SFCL, it is needed to control the three-phase four-wire PWM converter flexibly and reasonably. Thereby, the control strategy for the converter is analyzed in this paper. In dq0 reference frame, the mathematical model of the converter is founded. The double-loop control strategy, consisting of voltage outer loop and current inner loop, is presented. Moreover, the voltage balance control for the split DC link capacitors is also considered. Using MATLAB, the simulation model of the integrated active SFCL is built. According to the simulation results, it is known that, the presented control strategy is feasible and valid, and the converter can work well under unsymmetrical and symmetrical fault conditions, and then the fault current can be limited quickly and effectively.
Lorentz, V. R. H.; Schwarzmann, H.; März, M.; Bauer, A. J.; Ryssel, H.; Frey, L.; Poure, P.; Braun, F.
2011-08-01
A novel CMOS integrated pulse-width modulation (PWM) control circuit allowing smooth transitions between conversion modes in full-bridge based bi-directional DC-DC converters operating at high switching frequencies is presented. The novel PWM control circuit is able to drive full-bridge based DC-DC converters performing step-down (i.e. buck) and step-up (i.e. boost) voltage conversion in both directions, thus allowing charging and discharging of the batteries in mobile systems. It provides smooth transitions between buck, buck-boost and boost modes. Additionally, the novel PWM control loop circuit uses a symmetrical triangular carrier, which overcomes the necessity of using an output phasing circuit previously required in PWM controllers based on sawtooth oscillators. The novel PWM control also enables to build bi-directional DC-DC converters operating at high switching frequencies (i.e. up to 10 MHz and above). Finally, the proposed PWM control circuit also allows the use of an average lossless inductor-current sensor for sensing the average load current even at very high switching frequencies. In this article, the proposed PWM control circuit is modelled and the integrated CMOS schematic is given. The corresponding theory is analysed and presented in detail. The circuit simulations realised in the Cadence Spectre software with a commercially available 0.18 µm mixed-signal CMOS technology from UMC are shown. The PWM control circuit was implemented in a monolithic integrated bi-directional CMOS DC-DC converter ASIC prototype. The fabricated prototype was tested experimentally and has shown performances in accordance with the theory.
Energy Technology Data Exchange (ETDEWEB)
Suul, Jon Are
2012-03-15
Three-Phase Voltage Source Converters (VSCs) are finding widespread applications in grid integrated power conversion systems. The control systems of such VSCs are in an increasing number of these applications required to operate during voltage disturbances and unbalanced conditions. Control systems designed for grid side voltagesensor-less operation are at the same time becoming attractive due to the continuous drive for cost reduction and increased reliability of VSCs, but are not commonly applied for operation during unbalanced conditions. Methods for voltage-sensor-less grid synchronization and control of VSCs under unbalanced grid voltage conditions will therefore be the main focus of this Thesis. Estimation methods based on the concept of Virtual Flux, considering the integral of the converter voltage in analogy to the flux of an electric machine, are among the simplest and most well known techniques for achieving voltage-sensor-less grid synchronization. Most of the established techniques for Virtual Flux estimation are, however, either sensitive to grid frequency variations or they are not easily adaptable for operation under unbalanced grid voltage conditions. This Thesis addresses both these issues by proposing a simple approach for Virtual Flux estimation by utilizing a frequency-adaptive filter based on a Second Order Generalized Integrator (SOGI). The proposed approach can be used to achieve on-line frequency-adaptive varieties of conventional strategies for Virtual Flux estimation. The main advantage is, however, that the SOGI-based Virtual Flux estimation can be arranged in a structure that achieves inherent symmetrical component sequence separation under unbalanced conditions. The proposed method for Virtual Flux estimation can be used as a general basis for voltage-sensor-less grid synchronization and control during unbalanced conditions. In this Thesis, the estimated Virtual Flux signals are used to develop a flexible strategy for control of active
A Dual-Bridge LLC Resonant Converter with Fixed-Frequency PWM Control for Wide Input Applications
DEFF Research Database (Denmark)
Xiaofeng, Sun; Li, Xiaohua; Shen, Yanfeng;
2017-01-01
. Compared with the traditional pulse frequency modulation (PFM) controlled HB/FB LLC resonant converter, the voltage gain range is independent of the quality factor and the magnetizing inductor has little influence on the voltage gain, which can simplify the parameter selection process and benefit...... the design of magnetic components as well. Over the full load range, zero voltage switching (ZVS) and zero current switching (ZCS) can be achieved for primary switches and secondary rectifier diodes, respectively. Detailed analysis on the modulation schedule and operating principle of the proposed converter......This paper proposes a dual-bridge (DB) LLC resonant converter for wide input applications. The topology is an integration of a half-bridge (HB) LLC circuit and a full-bridge (FB) LLC circuit. The fixed-frequency PWM control is employed and a range of twice the minimum input voltage can be covered...
DEFF Research Database (Denmark)
Liu, Dong; Deng, Fujin; Zhang, Qi
2017-01-01
The current imbalance among the two input capacitors is one of the important issues of the half-bridge threelevel (HBTL) DC/DC converter, which would affect system performance and reliability. In this paper, a zero-voltage switching (ZVS) pulse-wide modulation (PWM) strategy including two operation...... modes is proposed. Based on the proposed ZVS PWM strategy, a capacitor current-balancing control is proposed for the HBTL DC/DC converter, where the currents on the two input capacitors can be kept balanced by alternating the two operation modes of the proposed ZVS PWM strategy. Therefore, the proposed...... control strategy can improve the performance and reliability of the converter in the aspect of balancing the thermal stresses and lifetimes among the two input capacitors. Finally, simulation and experimental studies are conducted and results verify the proposed control strategy....
An Algebraic Method of Synchronous Pulsewidth Modulation for Converters for Adjustable Speed Drives
DEFF Research Database (Denmark)
Oleschuk, Valentin; Blaabjerg, Frede
2002-01-01
This paper describes the basic peculiarities of a new method of feedforward synchronous pulsewidth modulation (PWM) of the output voltage of converters, based on one-stage closed-form strategy of PWM with pure algebraic control dependencies. It is applied to voltage source inverters...... with a continuous scheme of conventional voltage space vector modulation and with two basic variants of symmetrical discontinuous PWM. Simulations give the behaviour of the proposed method and show the advantage of algebraic synchronous PWM compared with the typical asynchronous, for low indices of the frequency...
An Algebraic Method of Synchronous Pulsewidth Modulation for Converters for Adjustable Speed Drives
DEFF Research Database (Denmark)
Oleschuk, Valentin; Blaabjerg, Frede
2002-01-01
This paper describes the basic peculiarities of a new method of feedforward synchronous pulsewidth modulation (PWM) of the output voltage of converters, based on one-stage closed-form strategy of PWM with pure algebraic control dependencies. It is applied to voltage source inverters...... with a continuous scheme of conventional voltage space vector modulation and with two basic variants of symmetrical discontinuous PWM. Simulations give the behaviour of the proposed method and show the advantage of algebraic synchronous PWM compared with the typical asynchronous, for low indices of the frequency...
五相电压源逆变器的空间矢量脉宽调制方法研究%Research of Space Vector PWM Techniques for Five-phase Voltage Source Inverter
Institute of Scientific and Technical Information of China (English)
高宏伟; 杨贵杰; 刘剑
2014-01-01
To improve the DC bus voltage utilization of five-phase voltage source inverter (VSI) and reduce the harmonic component of output phase voltages, a space vector pulse width modulation (SVPWM) algorithm of five-phase VSI based on adjacent four voltage vectors was proposed. According to the value of modulation index, the modulation range could be divided into sine modulation region and non-sine modulation region. In sine modulation region, the output phase voltages are standard sine waves without any harmonic component through allocating the action time of space vector appropriately. In non-sine modulation region, through optimizing the voltage vector in harmonic subspace, not only the DC bus voltage utilization is improved effectively, but also the harmonic component of output phase voltages is minimized. Simulation and experimental results verify the correctness and feasibility of the proposed algorithm.%为提高五相电压源逆变器(voltage source inverter，VSI)的直流母线电压利用率，减少输出相电压中所含的谐波分量，提出一种改进的基于最近四矢量的五相 VSI 空间矢量脉宽调制算法。根据调制系数的不同，将整个调制范围分为正弦调制区和非正弦调制区。在正弦调制区，通过合理分配空间矢量的作用时间，使得输出相电压为标准正弦波形，不含有任何谐波成分；在非正弦调制区，通过对谐波子空间内的电压矢量进行优化控制，在进一步提高直流母线电压利用率的同时，保证输出相电压中所含谐波分量更少，使逆变器工作在最优状态。仿真和实验结果验证了所提算法的正确性和可行性。
Directory of Open Access Journals (Sweden)
Imen Ouerdani
2017-03-01
Full Text Available This paper focuses on the carrier disposition Pulse Width Modulation (PWM strategies for Modular Multilevel Converters (MMC. The authors propose a new Phase Opposition Disposition PWM (PODPWM scheme applicable regardless of the converter’s sub-modules number. Moreover, a capacitor voltage sorting algorithm is synthesized aiming to ensure the converter’s balanced operation. Simulation results of a 3.6 MVA, 3-SM-MMC are presented and discussed. In addition, a Hardware In the Loop (HIL validation of the proposed PODPWM has been made using Field Programmable Gate Array (FPGA target. The actual power system (the 3-SM-MMC and the 3-phase RL load is then replaced by its real-time emulator. The latter is interfaced to the PODPWM control under test and both are implemented and run altogether in the same Xilinx XC7Z020 Zynq FPGA device. The obtained real-time HIL emulation results are presented and compared to the offline simulation results.
Institute of Scientific and Technical Information of China (English)
高洋; 尹忠东
2011-01-01
For Electric Vehicle (EV) chargers, the modified strategy of Direct Power Control based on voltage source PWM rectifier is proposed. First, the topological structure of PWM rectifier is introduced. Then the basic principle and control characteristic of traditional Direct Power Control (DPC) system with six interval divisions is analyzed, based on which a control method with twelve interval divisions is proposed to improve the control characteristics. Then this new method is deduced in detail, and the switch table which is defined by this method is proposed. Finally, the modified Direct Power Control method is validated by PSCAD, and simulation on the switch table is implemented by using of QuartusII9.0, which shows that each data can reach its predefined index.%针对电动汽车充电器,提出了基于电压型PwM整流器的改进的直接功率控制策略.首先,介绍了PWM整流器的拓扑结构;然后分析了传统的六区间直接功率控制系统的基本原理和控制特性;为了改善控制特性,在传统六区间的控制方法的基础上,提出了十二区间的控制方法,并对该方法进行了详细推导和阐述,给出了在该方法定义下的开关表;最后用PSCAD对改进的直接功率控制方法进行了可行性验证,用QuartusII9.0对开关表进行了仿真,发现各项数据都可以达到预期指标.
双PWM变换器一体化控制策略%Integrated control strategy for dual-PWM converter
Institute of Scientific and Technical Information of China (English)
李昆鹏; 万健如; 宫成; 李世群
2013-01-01
针对双PWM变换器依赖附加协调控制策略解决一体化的问题,研究PWM整流器及逆变器独立控制策略对协调性能的影响,借助瞬时功率中间变量,提出一种不外加其他协调方法的双PWM变换器一体化控制策略.整流器侧建立在离散化数学模型基础上,在固定时间周期内,以满足指标函数最小为原则预测下一时刻电网电流,借助空间矢量调制技术获得整流器期望开关状态.逆变器侧采用基于空间矢量调制技术的直接转矩控制.理论分析表明,由负载参数变化直接引起的直流母线电压波动通过电压环调节以瞬时功率形式作用于整流器电网电流预测环节.仿真和实验结果表明,双PWM变换器能快速响应负载变化情况并恢复稳态,对负载及系统参数扰动具有鲁棒性,验证了所提策略的有效性.%Aiming at the problem that dual pulse width modulation (PWM) converter relys on additional coordination control strategy to realize integrative control, the influences of PWM rectifier and inverter to coordination are studied. An integrated control strategy for dual PWM converter that not depends on the other harmonious methods is presented by use of the middle variable of instantaneous power. The control strategy for rectifier was built on the discrete mathematical model, and a cost function was chosen for pre dicting ac input current through minimizing itself in fixed cyclical time. Meanwhile, the state of switches for rectifier was determined with the help of space vector pulse width modulation technology. The control strategy for inverter adopted direct torque control method based on the space vector pulse width modula tion technique. A theoretical analysis shows that load parameter variation causes fluctuation of DC-bus voltage, and the fluctuation in instantaneous power shape acts on the predictive current for rectifier by voltage loop. The experiment and simulation results show quick response to the
Institute of Scientific and Technical Information of China (English)
郜阳; 胡家喜; 郭世明; 陈涛; 刘林曼
2012-01-01
电力电子设备中，诸如二极管、晶闸管等都会带来非线性和谐波电流等问题。三相电压型PWM整流器有输入电流接近正弦、功率因数可控、能量双向流动等特点，采用这种整流器可以解决非线性和谐渡电流问题，需要在电路中加入滤波器。传统纯电感L滤波器的电感值一般比较大，就会出现装置体积大、成本高、系统的动态响应慢等问题。文章采用LCL滤波器代替L滤波器，因LCL滤波器电感取值比L滤波器电感取值小，能够解决传统滤波器所带来的问题。通过Matlab建模仿真，验证了理论分析的正确性。%The problems such as nonlinear and harmonic current etc. are existing in power electronic devices(e.g., diode and thyristor rectifiers ). A solution to avoid mentioned problems is adopted by using the three-phase PWM rectifier which has the characteristics of input current closing to sinusoidal, controllable reactive power and hi-directional power flow capability. We should add filter to the circuit in order to eliminate distortion and harmonious. Because inductance value of traditional L filter with pure inductance is usually large, the problems such as large volume, high cost and slow dynamic response will arise. Traditional L filter is replaced by the LCL filter, on an account of inductor value of LCL filter smaller than the L filter's, which can solve the problems brought by the traditional filter. ThrOugh the Matlab modeling and simulation, the correctness of theory analysis is verified.
Institute of Scientific and Technical Information of China (English)
侯世英; 张诣
2011-01-01
Aiming at the problems that classic phase-locked loop (PLL) has low response speed and detection accuracy under frequency offset of network voltage conditions, a novel analog signal PLL based on coordinate transformation is proposed, and based on the PLL, the model of three-phase voltage source pulse width modulation (PWM) rectifier is built. The rectifier adopts the modulation method of space vector pulse width modulation(SVPWM). According to the circuit topology of the PWM rectifier, the framework of control strategy is given. Also the circuit topology and working principle of PLL are analyzed. Finally, a simulation is done through the Matlab. Simulation results show that the PLL can track the network frequency so well that it can realize phase locking. And the novel PLL can also achieve phase locking under the condition of frequency drift of three-phase network voltage.%为了解决在电网电压出现频率偏移时,传统锁相环响应速度慢、锁相精度差的问题,提出一种基于坐标变换理论的新型模拟信号锁相环,并建立了基于模拟信号锁相环的三相电压型PWM整流器模型.该整流器采用空间矢量脉宽调制(Space Vector Pulse Width Modulation,SVPWM).在对所提PwM整流器的基本拓扑进行分析的基础上,给出了控制策略框图,并分析了新型锁相环的电路结构和工作原理.通过Matlab对所建模型进行了仿真.仿真结果表明:模拟信号锁相环能够快速跟踪系统频率的变化,实现锁相功能.同时,在三相电网电压频率出现小范围漂移情况下,新型锁相环也能够准确锁相.
Institute of Scientific and Technical Information of China (English)
朱晋; 韦统振; 李东; 贾东强; 马明
2013-01-01
Alternate-arm multi-level converter (A2MC) is a new voltage source converter high voltage direct current transmission (VSC-HVDC) converter topology. This paper describes the principle of a improved full-bridge alternate-arm multi-level converter. Sub-unit capacitance parameters are designed based on the energy balancing of the arm. A simple and effective voltage control strategy and bridge arm inductance parameter selection method is given to balance the sub-unit capacitor voltage. The correctness and feasibility of the present control strategy and capacitance and inductance parameter design method are verified by the three-phase simulation model built in PSIM and single-phase prototype built in the laboratory.% 变桥臂多电平变流拓扑(alternate-arm multi-level converter，A2MC)是应用于电压源换流器直流输电的新型多电平换流器拓扑。该文阐述了一种新型全桥变桥臂多电平变流拓扑(full-bridge alternate-arm voltage source converter, FA2MC)的工作原理；针对该新型换流器拓扑，从桥臂能量平衡的角度，对其子单元电容参数进行了合理设计，并针对各子单元电容电压均衡的问题，给出了一种简单有效的电压控制策略及桥臂电感参数选取依据。对该拓扑进行了三相并网模型 PSIM 仿真，并在实验室制作了单相样机，得到的仿真及实验波形验证了该拓扑结构的电容电感参数设计及子单元电容恒压策略的正确性和可行性。
A dual voltage control strategy for single-phase PWM converters with power decoupling function
DEFF Research Database (Denmark)
Tang, Yi; Qin, Zian; Blaabjerg, Frede
2014-01-01
The inherent double line ripple power in singlephase systems is adverse to the converter performance, e.g. limited lifetime due to the requirement of large electrolytic capacitors and low voltage control bandwidth due to harmonic disturbance. In this paper, an active converter topology based...... on a symmetrical half bridge circuit is proposed to decouple the ripple power so that balanced instantaneous power flow is assured between source and load, and the required dc-link capacitance can be dramatically reduced. For proper closed-loop regulation, the small signal modeling of the proposed system...... is presented, and a dual voltage control strategy is then proposed, which comprises one voltage loop implemented in the synchronous reference frame for active power balancing, and another one implemented in the harmonic reference frame for ripple power compensation. Special attention is given to the bandwidth...
A dual voltage control strategy for single-phase PWM converters with power decoupling function
DEFF Research Database (Denmark)
Tang, Yi; Qin, Zian; Blaabjerg, Frede
2015-01-01
converter topology based on a symmetrical half bridge circuit is proposed to decouple the ripple power so that balanced instantaneous power flow is assured between source and load, and the required dc-link capacitance can be dramatically reduced. For proper closed-loop regulation, the small signal modeling......The inherent double line ripple power in single-phase systems is adverse to the performance of power electronics converters, e.g. limited lifetime due to the requirement of large electrolytic capacitors and low voltage control bandwidth due to harmonic disturbance. In this paper, an active...... of the proposed system is presented, and a dual voltage control strategy is then proposed, which comprises one voltage loop implemented in the synchronous reference frame for active power balancing, and another one implemented in the stationary reference frame for ripple power compensation. Special attention...
Smooth-Transition Simple Digital PWM Modulator for Four-Switch Buck-Boost Converters
Rodriguez, Alberto; Rodriguez, Miguel; Vazquez, Aitor; Maija, Pablo F.; Sebastian, Javier
2014-08-01
Four Switch non-inverting Buck-Boost (4SBB) converters are extensively used in non-isolated applications where voltage step-up and step-down are required. In order to achieve high efficiency operation it is preferred to control the 4SBB as a Buck or Boost converter, depending on the input/output voltage ratio. However, when input and output voltages are close this approach requires near- unity conversion ratios, which are difficult to achieve in practice. Several alternative operating modes have been proposed in the literature to overcome this issue. In particular, operating the 4SBB as a Buck and Boost at the same time (Buck+Boost mode) has proven to be adequate to achieve near-unity conversion ratios.This paper proposes a simple, hardware-efficient digital pulse width modulator for a 4SBB that enables operation in Buck, Boost and Buck+Boost modes, thus allowing near-unity conversion ratios, while achieving smooth transitions between the different modes. The proposed modulator is simulated with Simulink and experimentally demonstrated using a 500W 4SBB converter with 24V input voltage and 12V-36V output voltage range.
DEFF Research Database (Denmark)
Huang, Shaojun; Mathe, Laszlo; Teodorescu, Remus
2013-01-01
of inaccuracy in terms of switching instant, while the latter is inflexible with higher cost. In order to overcome these drawbacks, this paper proposes an alternative solution, which uses high frequency saw-tooth carrier and two independent comparators, usually available in microcontrollers, to create......Two existing methods to implement resampling modulation technique for modular multilevel converter (MMC) (the sampling frequency is a multiple of the carrier frequency) are: the software solution (using a microcontroller) and the hardware solution (using FPGA). The former has a certain level...
EFFICIENT STEADY-STATE ANALYSIS METHOD FOR CLOSED-LOOP PWM SWITCHING CONVERTERS
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
Since the early70s,many s mall-signal fre-quency-domain modeling technique have been de-veloped to study the dynamic perfor mances and sta-bilities ofPWMs witching converters around thestatic operating point.However,the accuracy of thederived models relies on accurate deter mination ofthe steady state operating point,and usually manyperfor mances of circuits are given based on steady-state,so it is very essential to analyze the steadystate of circuits.Analysis methods for steadystate ofnonlinear circuits ca...
Institute of Scientific and Technical Information of China (English)
刘勇; 黎建勋
2015-01-01
Electric propulsion system has been used widely in fishing vessels the technology improving. Electric propulsion system with three-phase PWM rectifier, has already been mature in the technology. But for part of fishing vessel with single-phase AC power supply system, the research and application for electric propulsion system is less. This paper introduces the basic principlesof single-phase voltage source PWM rectifier, analyze the predictive current control methods. The dynamic response and the static precision of four-quadrant converter with predictive current control methodsare much better. In this paper, through computer simulations to verify the feasibility of predictive current control methods and validity of the main circuit parameter selection. Then, through experimental platform debugging which withTMS320LF2407 DSP chip as the core, the result is very well coincident with the simulated result. It shows that this method has good dynamic and static performance, can meet the need of four-quadrant converter design requirementscompletely. It is an ideal control method.%随着电力推进系统在我国渔业船舶上的不断推广应用，在系统中采用三相交流PWM整流器在技术上已经比较成熟。本文从单相电压型PWM整流器的基本原理出发，对预测电流控制方法进行了分析，认为该方法进一步改善了四象限变流器的动态响应特征，提高了稳态控制精度。通过计算机仿真试验，验证了预测电流算法的可行性以及主电路参数选择的正确性，并在仿真的基础上，以TMS320LF2407 DSP控制芯片为核心，实现了预测电流控制算法在三相PWM整流器小功率实验平台上的软件调试。试验结果与仿真有很好的一致性，表明该方法具有较好的动态、静态性能，完全能够达到四象限变流器的设计要求，是一种比较理想的控制方法。
A PWM Buck Converter with High-efficiency under Light-load%一种具有高轻载效率的PWM Buck变换器
Institute of Scientific and Technical Information of China (English)
刘南; 梁亮
2013-01-01
本文提出了一种在轻载工作环境下依然高效的PWM DC/DC buck变换器.该变换器由TSMC 1.8/3.3 V 0.18 μmCMOS技术设计而成.通过DCM操作,不仅能在满载时达到高效率,而且在不利用任何PFM技术的情况下大大提升轻载下的效率.这种变换器轻载时的输出精确性和输出纹波都优于PFM变换器,而在满载时与普通的PWM变换器同样稳定、高效,通过Saber仿真与电路实验验证了变换器的可行性.
Influence of voltage source converter grounding mode on DC distribution system%电压源换流器接地方式对直流配电系统的影响
Institute of Scientific and Technical Information of China (English)
鲁国正; 高亮; 梁智敏
2016-01-01
For the low voltage direct current (LVDC) distribution system, the advantages and disadvantages of the different grounding modes of the voltage source converterare analyzed and compared. In the converter capacitor directly grounding and high resistance grounding mode, the converter AC outlet of asymmetric fault characteristics and DC line pole grounding faultcharacteristicsare analyzed,and the LVDC electromagnetic transient model is established and studied by simulation. Comparison of the system transient performance under different operating conditions shows that voltage source converter capacitor high resistance grounding mode is better than the direct grounding way. High resistance grounding to limit fault current is more favorable, and it is also beneficial to the rapid recovery after the DC power distribution system is eliminated, which lays the foundation for the protection scheme of DC power distribution system in the future.%针对低压直流(Low Voltage Direct Current, LVDC)配电系统分析比较了电压源换流器不同接地方式的优缺点。分别在换流器电容中点直接接地和高阻接地方式下，对换流器交流出口处不对称故障特性和直流线路单极接地故障特性进行了分析，并建立LVDC电磁暂态模型进行了仿真研究。对比系统不同工况下的暂态性能可知，电压源换流器电容中点高阻接地方式优于直接接地方式。高阻接地的方式对限制故障电流更为有利，同时也有利于直流配电系统故障消除后的快速恢复，这为未来直流配电系统保护方案的配置奠定了基础。
桥式直流PWM变换器的建模与仿真研究%Research on Modeling and Simulation of bridge DC PWM converter
Institute of Scientific and Technical Information of China (English)
朱莉波; 荣军; 王峰; 刘正; 钟颖
2015-01-01
首先介绍了PWM控制技术的基本原理，然后结合无源逆变器，详细地阐述了桥式直流PWM变换器的工作原理。最后在MATLAB/Simulink建立了桥式直流PWM变换器的仿真模型，然后对仿真结果进行了分析，仿真结果表明通过调节占空比，可以改变电压和电流的大小和方向，与理论分析完全一致。%The paper firstly introduces the basic principle of PWM control technology, and then combines with passive inverter, and also expounds in detail the working principle of PWM bridge DC converter. Finally, the simulation model is built in the MATLAB/Simulink of bridge DC PWM converter, and then the simulation results have been carried on the analysis. The simulation results show that the size and the direction of the voltage and current can be changed by adjusting the duty ratio, and it is fully consistent with the theoretical analysis.
Energy Technology Data Exchange (ETDEWEB)
Gheraia, H.; Berkouk, E.M. [ENP, Alger (Algeria). Lab. de Commande des Processus; Manesse, G. [CNAM-Paris (France). Lab. d' Electricite Industrielle
2001-08-01
In this paper, we study a new kind of continuous-alternating converters: a seven-level neutral point clamping (NPC) voltage source inverter (VSI). We propose this inverter for applications in high voltage and high power fields. In the first part, we develop the knowledge and the control models of this inverter using the connections functions of the semi-conductors. After that, we present two pulse width modulation (PWM) algorithms to control this converter using its control model. We propose these algorithms for digital implementation. This multilevel inverter is associated to the induction machine. The performances obtained are full of promise to use it in the high voltage and high power fields of electrical traction. (orig.)
Research on Double PWM Converter Based on the Soft-Switch Technology%零压变换软开关的双PWM变换器的研究
Institute of Scientific and Technical Information of China (English)
胡正轩; 冷光夺; 袁冬柏; 王建任
2013-01-01
Double Pulse Width Modulation (PWM) converter in wind power system is used widely, the power switch device Insulated Gate Bipolar Transistor (IGBT) has the good switching characteristics. However,the circuit which is opened or turn off will produce switch loss and noise pollution. These interference in small power circuits can be ignored, but it should be avoid in the larger wind power system. In order to reduce or even avoid these disadvantages influence to the running of system smoothly, this paper design a Double PWM converter which is based on the soft-switching technology, and it combines with Space Vector Pulse Width Modulation (SVPWM) technique and PR control method. The simulation test and analysis results proved that optimal converter can be a good improvement in input and output performance of traditional converter.%对于双脉宽调制(PWM)变换器,当电路开通或关断的时候都会产生开关损耗和噪声污染.这些干扰在小功率电路中可以被忽略,但在较大型的风力发电系统中是应该极力避免的.为了减小甚至避免这些不利因素影响系统的平稳运行,设计了一种基于零电压变换软开关技术的双PWM变换器,并且结合了空间矢量脉宽调制技术和PR控制方法.通过仿真试验和结果分析,验证了优化的变换器能够很好地改善传统变换器的输入和输出性能.
Institute of Scientific and Technical Information of China (English)
冯阳; 王奔; 王亚芳; 马明智
2014-01-01
Using the current mode PWM rectifier technology in the cascade speed regulation system for motor can e-liminate the need for the dc Boost chopper of the voltage - type converter cascade speed regulation system,thus,sim-plify the topology of the system,and improve the power factor of the regulation system and reduce the content of the transformer network side harmonic. But thecurrent mode PWM inverter under the dq coordinate system is a nonlinear coupling system,which is not conducive to the controller design,so This paper proposed precise linearization to line-arize and decouple the original system,constructed its pseudo linear system model,and designed a closed loop con-troller of the pseudo linear system by usingthe sliding mode variable structure control theory. At the same time,in the Matlab / Simulink software,a simulation model was established based on this control strategy. The simulation results showed that the control strategy could achieve rapidand effective regulation of the motor speed,and meanwhile could improve th epower factor of the system and reduce the harmonic content.%采用电流型 PWM 整流技术的串级调速系统，省去了电压型斩波串级调速系统中的直流 Boost 斩波环节，简化了系统的拓扑结构，同时也能够实现系统功率因数的提高和变压器网侧谐波含量的减少。考虑到电流型PWM 逆变器在 dq 坐标系下是一个非线性耦合系统，不利于控制器的设计，采用精确线性化方法对原系统进行线性化并解耦，构造其伪线性系统模型，运用滑模变结构控制理论设计该伪线性系统的闭环控制器。同时，在Matlab/ Simulink 软件下，建立了基于此控制策略的模型并进行仿真。结果表明，该控制策略可实现电动机转速的快速、有效调节，同时可提高系统的功率因数，减少谐波含量。
Electrical machine PWM loss evaluation basics
Energy Technology Data Exchange (ETDEWEB)
Ruderman, A. [The School of Engineering, Bar-Ilan Univ., Ramat-Gan (Israel); Welch, R. Jr. [IEEE, Welch Enterprise, Oakdale (United States)
2005-07-01
Modern power converters utilize pulse-width modulation (PWM) voltage control. Output voltage high frequency harmonics induce additional electrical machine loss. As there is no accepted PWM loss theory, PWM loss is usually accounted for by machine power de-rating. In-depth understanding of PWM loss mechanisms is important for predicting losses and improving energy efficiency of electrical machines. In this paper we suggest a new time domain PWM loss approach. It assumes that PWM eddy current iron loss dominates over PWM copper and hysteresis iron losses and comprises theoretical normalized PWM loss evaluation and experimental characterization. Once maximal PWM loss is measured, it can be scaled for an arbitrary operating point using simple formula. Theoretical results are shown to be in a good agreement with a published experimental data. (orig.)
Directory of Open Access Journals (Sweden)
Ying-Pei Liu
Full Text Available In order to improve the performance of voltage source converter-high voltage direct current (VSC-HVDC system, we propose an improved auto-disturbance rejection control (ADRC method based on least squares support vector machines (LSSVM in the rectifier side. Firstly, we deduce the high frequency transient mathematical model of VSC-HVDC system. Then we investigate the ADRC and LSSVM principles. We ignore the tracking differentiator in the ADRC controller aiming to improve the system dynamic response speed. On this basis, we derive the mathematical model of ADRC controller optimized by LSSVM for direct current voltage loop. Finally we carry out simulations to verify the feasibility and effectiveness of our proposed control method. In addition, we employ the time-frequency representation methods, i.e., Wigner-Ville distribution (WVD and adaptive optimal kernel (AOK time-frequency representation, to demonstrate our proposed method performs better than the traditional method from the perspective of energy distribution in time and frequency plane.
Liu, Ying-Pei; Liang, Hai-Ping; Gao, Zhong-Ke
2015-01-01
In order to improve the performance of voltage source converter-high voltage direct current (VSC-HVDC) system, we propose an improved auto-disturbance rejection control (ADRC) method based on least squares support vector machines (LSSVM) in the rectifier side. Firstly, we deduce the high frequency transient mathematical model of VSC-HVDC system. Then we investigate the ADRC and LSSVM principles. We ignore the tracking differentiator in the ADRC controller aiming to improve the system dynamic response speed. On this basis, we derive the mathematical model of ADRC controller optimized by LSSVM for direct current voltage loop. Finally we carry out simulations to verify the feasibility and effectiveness of our proposed control method. In addition, we employ the time-frequency representation methods, i.e., Wigner-Ville distribution (WVD) and adaptive optimal kernel (AOK) time-frequency representation, to demonstrate our proposed method performs better than the traditional method from the perspective of energy distribution in time and frequency plane.
Space Vector Pulse Width Modulation Scheme for a Seven-Phase Voltage Source Inverter
Directory of Open Access Journals (Sweden)
Mohd. Arif Khan
2011-09-01
Full Text Available This paper analyses a simple space vector PWM (SVPWM scheme for a seven-phase voltage source inverter. At first the conventional method of producing sinusoidal output voltage by utilizing six active and a zero space vectors are used to synthesis the input reference and then new PWM scheme called time equivalent space vector PWM is presented. A comparison of the proposed scheme with the conventional scheme is presented based on various performance indices. Extensive Simulation results are provided to validate the findings
Directory of Open Access Journals (Sweden)
R. Silva-Ortigoza
2014-01-01
Full Text Available Sliding mode control is a discontinuous control technique that is, by its nature, appropriate for controlling variable structure systems, such as the switch regulated systems employed in power electronics. However, when designing control laws based on the average models of these systems a modulator is necessary for their experimental implementation. Among the most widely used modulators in power electronics are the pulse width modulation (PWM and, more recently, the sigma-delta-modulator (Σ-Δ-modulator. Based on the importance of achieving an appropriate implementation of average control laws and the relevance of the trajectory tracking task in DC/DC power converters, for the first time, this research presents the assessment of the experimental results obtained when one of these controllers is implemented through either a PWM or a Σ-Δ-modulator to perform such a task. A comparative assessment based on the integral square error (ISE index shows that, at frequencies with similar efficiency, the Σ-Δ-modulator provides a better tracking performance for the DC/DC Buck converter. In this paper, an average control based on differential flatness was used to perform the experiments. It is worth mentioning that a different trajectory tracking controller could have been selected for this research.
Kondo, Yosuke; Natchpong, Hatti; Akagi, Hirofumi
This paper discusses a 6.6-kV transformerless motor drive system based on the back-to-back connection of two five-level diode-clamped PWM converters. In addition, this paper designs, constructs and experimentally tests a down-scaled model rated at 200V and 5.5kW. This system consist of the two five-level converters, a common dc-link, and voltage-balancing circuits using two bi-directional buck-boost choppers. Experimental results obtained from the down-scaled model verify the validity of the system design, giving promise of the viability of the 6.6-kV transformerless motor drive system.
Note: Galvanic isolated voltage source using a single photodiode.
Stoican, O S
2010-04-01
A galvanic isolated voltage source able to provide several volts by using a single photodiode is described. A pulse-modulated laser beam is sent to a photodiode. By using a step-up transformer the amplitude of the variable voltage generated by the photodiode is increased. Adding a rectifier cell the variable voltage is converted back into a dc voltage.
Design of a New AC–DC Single-Stage Full-Bridge PWM Converter with Two Controllers
Directory of Open Access Journals (Sweden)
R. Ramesh,
2014-03-01
Full Text Available Single phase power factor correction ac-dc converters are widely used in industry for ac-dc power conversion from single phase ac mains to an required output dc voltage. In case of high power application these types of converter use an ac-dc boost converter followed by dc-dc converter. These converters has the features of excellent input power factor, continuous input and output currents, and intermediate dc bus voltage and reduce the number of semiconductor devices for such cost-effective applications.
A novel three-phase-bridge cascaded PWM converter%一种新型的三相桥级联型PWM变换器
Institute of Scientific and Technical Information of China (English)
陆治国; 赵丽丽; 吴春军; 祝万平
2012-01-01
The traditional single-phase cascaded H-bridge converter (CHBC) can not be used for three-phase high-voltage applications directly, thus a novel topology of three-phase-bridge (3P-Bridge) cascaded PWM converter is proposed and its basic cell is a 3P-Bridge. Its construction idea is analyzed and the currents and power expressions are derived. The proposed topology in this paper can not only be operated as a rectifier but also an inverter. One-cycle control (OCC) and CPS-PWM are employed for their simulation research separately. Simulation results verify the feasibility of the proposed 3P-Bridge cascaded converter and show that the proposed topology can improve the voltage level, and comparing with the traditional single-phase CHBC, it can reduce the number of switches and DC capacitors (or separated DC sources), and the voltage ripple at DC side is smaller. So the proposed 3P-Bridge cascaded converter has better prospect in three-phase high-voltage applications.%传统的单相级联H桥变换器不易直接应用于三相高压场合,为此提出了三相桥级联型PWM变换器的拓扑结构,其子模块为电压源型三相桥式变换器.分析了该新型拓扑的构成思想,推导了二级和三级级联拓扑的电流和功率表达式,其可做整流器也可做逆变器,分别采用单周控制和载波相移控制对其进行仿真研究.仿真结果验证了该新型拓扑的可行性,表明其能够提升电压等级,与传统的单相级联H桥变换器构成的三相变换器相比,能够节省开关管和直流侧电容(独立电源)个数,且直流侧电压纹波较小,在三相高压场合具有较好的应用前景.
Institute of Scientific and Technical Information of China (English)
钟庆; 黄凯; 王钢; 张尧
2014-01-01
不对称三相电压下，电压源型换流器(VSC)将产生低次谐波，给电网造成谐波污染。随着VSC在电力系统中的广泛应用，这类问题必须得到更多的关注，提出有效的解决方法。基于动态相量和序分量，推导出序分量动态相量，并对其特性进行了分析；将含开关函数描述的VSC时域模型转化为动态相量模型；定义交流电流和直流电压的各阶序分量动态相量为状态变量，建立了以状态空间描述的VSC序分量动态相量谐波分析模型，综合考虑了开关函数的详细动态特性和交直流侧谐波的相互作用，从而揭示了 VSC 产生谐波的机理，实现了 VSC 谐波的解析求解。在此基础上，提出负序补偿的不对称调制策略，以抑制低次谐波的产生。通过各种不对称情况下的仿真和计算，验证了所提出的谐波分析模型的正确性和谐波抑制策略的有效性。%A voltage source converter (VSC) will generate low-order harmonics under unbalanced three-phase voltage causing harmonic pollution to power grids.With the wide application of VSCs in power systems,the harmonic pollution must be eliminated and given more attention by finding effective solutions.Based on dynamic phasors and symmetrical components,the sequence dynamic phasor is deduced and its characteristics are analyzed.The time domain VSC model containing a description of switching function is transformed into a dynamic phasor model.By setting the sequence dynamic phasors of AC current and DC voltage as the state variables,a harmonic analysis model in the state space based on the sequence dynamic phasors of VSC is developed.The model considers both the dynamic performance of power electronic devices and the interaction between AC and DC sides thus revealing the mechanism of how VSC generates harmonics.Based on the model,the harmonics generated by VSC can be calculated analytically.A harmonic elimination strategy with an
Park, Sung-Yun; Cho, Jihyun; Lee, Kyuseok; Yoon, Euisik
2015-12-01
We report a pulse width modulation (PWM) buck converter that is able to achieve a power conversion efficiency (PCE) of > 80% in light loads 100 μA) for implantable biomedical systems. In order to achieve a high PCE for the given light loads, the buck converter adaptively reconfigures the size of power PMOS and NMOS transistors and their gate drivers in accordance with load currents, while operating at a fixed frequency of 1 MHz. The buck converter employs the analog-digital hybrid control scheme for coarse/fine adjustment of power transistors. The coarse digital control generates an approximate duty cycle necessary for driving a given load and selects an appropriate width of power transistors to minimize redundant power dissipation. The fine analog control provides the final tuning of the duty cycle to compensate for the error from the coarse digital control. The mode switching between the analog and digital controls is accomplished by a mode arbiter which estimates the average of duty cycles for the given load condition from limit cycle oscillations (LCO) induced by coarse adjustment. The fabricated buck converter achieved a peak efficiency of 86.3% at 1.4 mA and > 80% efficiency for a wide range of load conditions from 45 μA to 4.1 mA, while generating 1 V output from 2.5-3.3 V supply. The converter occupies 0.375 mm(2) in 0.18 μm CMOS processes and requires two external components: 1.2 μF capacitor and 6.8 μH inductor.
零电压转换PWMDC/DC变换器的研究%Research on Zero-voltage-transition PWM DC/DC Converters
Institute of Scientific and Technical Information of China (English)
高原; 邱新芸
2005-01-01
介绍了PWM DC/DC变换器的软开关控制.阐述了零电压转换PWM DC/DC变换器的缺点.研究了带吸收电容的零电压转换PWM DC/DC变换器电路.给出了仿真电路和仿真结果.
DEFF Research Database (Denmark)
Beltran, H.; Perez, E.; Chen, Zhe
2009-01-01
This paper describes a Fixed Maximum Power Point analog control used in a step-down Pulse Width Modulated power converter. The DC/DC converter drives a DC motor used in small water pumping installations, without any electric storage device. The power supply is provided by PV panels working around...
One-cycle-controlled Single-phase Half-bridge PWM Converter%单相半桥PWM变换器单周期控制研究
Institute of Scientific and Technical Information of China (English)
黄刚; 王友阳; 徐镭; 夏泽中
2015-01-01
在基本单周期控制基础上，提出一种单相半桥脉冲宽度调制变换器改进单周期控制算法，引进桥臂电容电压差值变量，构建桥臂电容电压闭环控制，明显改善了基本单周期控制算法应用在单相半桥脉冲宽度调制变换器中桥臂电容电压严重不平衡的问题，限制了桥臂电容中心点电压波动范围，使变换器系统稳定性增强，增强了带载能力，同时实现交流侧高功率。在理论分析的基础上，对控制算法进行了系统的建模仿真，仿真结果表明单相半桥变换器能改进单周期控制算法的有效性。%An improved one -cycle control algorithm was applied in single -phase half -bridge PWM converter .It was based on the basic one -cycle-controlled algorithm .The difference between the variable capacitor voltage arms was introduced to build the bridge arm capacitor voltage closed -loop control .This algorithm can improve the imbalance of the arm capacitor voltage in single-phase half-bridge PWM converter , and limit the fluctuation range of the center of the bridge capacitor volt-age.So the stability and the load capacity of the system could be enhanced .The high power factor in the AC side was achieved . Based on the theoretical analysis of this algorithm , system simulation was realized to demonstrate the effectiveness of this algo-rithm.
矩阵变换器的谐波注入PWM控制策略%Harmonic injected PWM control strategy for matrix converter
Institute of Scientific and Technical Information of China (English)
王汝田; 王秀云; 崔永恒
2013-01-01
The non-controlled rectification and HIPWM(Harmonic Injected PWM) are respectively applied to the virtual rectifier and virtual inverter of equivalent AC/DC/AC model for matrix converter.The virtual rectifier generates fluctuant DC voltage when symmetric or asymmetric three-phase voltages are supplied.The compensation function is deduced based on the concept of switching function for compensating the modulation wave to eliminate the effect of fluctuant DC voltage on the HIPWM output voltage of virtual inverter.Its hardware implementation is very simple.Results of simulation with MATLAB/Simulink show that,the voltage gain of matrix converter can reach to 0.866,the theoretical maximum,and there is no loworder harmonics in its output voltage,verifying the correctness and effectiveness of the proposed control strategy.%在矩阵变换器间接变换法等效的交直和直交2个虚拟的环节上,分别采用不控整流和谐波注入PWM(HIPWM)2种简单易实现的调制方式.在三相输入电压是对称或非对称的情况下,虚拟整流环节输出的是直流波动电压,为消除此直流波动电压对虚拟逆变环节HIPWM输出的电压波形的影响,利用开关函数概念推导了对HIPWM的调制波进行补偿的补偿函数,此控制策略的硬件实现电路非常简单.应用MATLAB/Simulink进行了仿真,仿真结果表明:应用HIPWM控制策略,矩阵变换器的电压增益能够达到理论最大值0.866,输出电压中不含低次谐波,验证了所提控制算法的正确性和有效性.
DEFF Research Database (Denmark)
Fatu, Marius; Tutelea, Lucian; Teodorescu, Remus;
2007-01-01
This paper presents concepts and tests results on a flexible sensorless control strategy for a PMSG driven by a small wind turbine with back-to-back power converters capable to function in both stand alone and grid connection mode. A new automatic seamless transfer method, based on phase...
DEFF Research Database (Denmark)
Lin, Ma; Kerekes, Tamas; Rodriguez, Pedro
2015-01-01
Photovoltaic systems technological development is driven by the request for higher efficiency and safety. These concerns influence also the choice of the power converter stage. Several topologies have been proposed and many of them are available commercially. Among them, the neutral point clamped...
Directory of Open Access Journals (Sweden)
P. Gopal,
2015-11-01
Full Text Available The main objective of this concept is to examine the operation of fundamental buck-based three-phase singlestage ac–dc full-bridge converters. In this concept, the operation of this fundamental converter is explained and analyzed, and a procedure for the design of its key components is derived and demonstrated with an example and general concluding remarks comparing Buck-Based and Boost Based three Phase single-stage AC to DC full Bridge converters are made.
DEFF Research Database (Denmark)
Fatu, Marius; Tutelea, Lucian; Teodorescu, Remus
2007-01-01
This paper presents concepts and tests results on a flexible sensorless control strategy for a PMSG driven by a small wind turbine with back-to-back power converters capable to function in both stand alone and grid connection mode. A new automatic seamless transfer method, based on phase-locked-l......This paper presents concepts and tests results on a flexible sensorless control strategy for a PMSG driven by a small wind turbine with back-to-back power converters capable to function in both stand alone and grid connection mode. A new automatic seamless transfer method, based on phase......-locked-loop technique, from grid connected to stand alone and vice versa in the event of a fault on grid is proposed. Tests results show the proposed method works properly...
Full Bridge ZVT—PWM DC—DC Converter①
Institute of Scientific and Technical Information of China (English)
WEIYanjun; QIHanhong; 等
1997-01-01
A new FB-ZVT-PWM converter is proposed.The new converter operates at a fixed frequency and implements ZVS for power devices without increasing voltage in both turn-on and turn-off transient.A 80kHz/50 W FB-ZVT-PWM boost converter using MOSFETs is analysed theoretically.
A battery-based, low-noise voltage source
Wagner, Anke; Sturm, Sven; Schabinger, Birgit; Blaum, Klaus; Quint, Wolfgang
2010-06-01
A highly stable, low-noise voltage source was designed to improve the stability of the electrode bias voltages of a Penning trap. To avoid excess noise and ground loops, the voltage source is completely independent of the public electric network and uses a 12 V car battery to generate output voltages of ±15 and ±5 V. First, the dc supply voltage is converted into ac-voltage and gets amplified. Afterwards, the signal is rectified, filtered, and regulated to the desired output value. Each channel can deliver up to 1.5 A. The current as well as the battery voltage and the output voltages can be read out via a universal serial bus (USB) connection for monitoring purposes. With the presented design, a relative voltage stability of 7×10-7 over 6.5 h and a noise level equal or smaller than 30 nV/√Hz is achieved.
Directory of Open Access Journals (Sweden)
Zulkifilie Bin Ibrahim
2014-03-01
Full Text Available Pulse width modulation (PWM technique is one of the vital issues for power electronic circuit control. A number of Pulse width modulation (PWM techniques are increasingly applied in many new industrial applications that require superior performance. The most widely applied PWM technique for three-phase voltage source inverters are Sine Pulse Width Modulation (SPWM, Third Harmonic Injection Pulse Width Modulation (THIPWM and Space Vector Pulse Width Modulation (SVPWM. SPWM is the most simple modulation technique that can realize easily in analog circuit. However, it has some drawbacks such as higher total harmonic distortion (THD, lower switching frequency and not capable in over modulation region. THIPWM and SVPWM both provide better THD compared to SPWM. SVPWM shows lower THD in over modulation region and in high frequency application compared to THIPWM. These three techniques are discussed, analyzed and compared in terms of modulation index, switching frequency and inverter input voltage in this paper. The modeling and simulation for all PWM techniques have been done by using MATLAB/SIMULINK and Origin 6.1. From the simulation results, SVPWM shows the best performance and meet IEEE 519 standard of current harmonics level.
Abolfazl Halavei Niasar; Ehsan Boloor Kashani
2013-01-01
Induction motors offer many advantages tools, and therefore are becoming very popular industrially and commercially. This paper presents the implementation of Xmega microcontroller based PWM inverter controlled of four-switch three phase voltage source inverter (FSTPI) fed induction motor drive. The reduction of the number of power switches from six to four improves the cost effectiveness, volume-compactness and reliability of the three phase inverters in addition to less complexity of contro...
Institute of Scientific and Technical Information of China (English)
屈克庆; 陈国呈; 孙承波
2005-01-01
A novel software implementation for current polarity detection and current compensation is presented. For a three-phase zero-voltage soft-switching (ZVS) PWM converter based on phase and amplitude control (PAC), when saw-tooth carriers with alternate positive and negative slopes are adopted, the positive or negative slopes are chosen according to the phase current polarity. Since polarity reversal causes current distortion, current at the instant of reversal should be compensated for. Based on the characteristic of unity power factor converter in rectification and regeneration modes, a software implementation for current polarity detection is proposed.Distortion of current zero-crossing caused by using saw-tooth carriers with alternate positive and negative slopes is analyzed, and the relevant compensation method is proposed. Experimental study with a 1.5 kW device shows that phase current has a small harmonic content and power factor is high both in rectification and regeneration modes.
DEFF Research Database (Denmark)
Qu, Hao; Yang, Xijun; Guo, Yougui
2014-01-01
-sequence component injection, in order to reduce power loss and increased overall efficiency. And then by reconstructing the other two phase input voltages and currents, the transformation from stationary frame (abc) to rotating frame (dq frame) is designed. Finally, a PI regulator based controller for single......Single-phase voltage source converter (VSC) is an important power electronic converter (PEC), including single-phase voltage source inverter (VSI), single-phase voltage source rectifier (VSR), single-phase active power filter (APF) and single-phase grid-connection inverter (GCI). Single-phase VSC...
Digital resonant current controllers for voltage source converters
Gomez Yepes, Alejandro
2011-01-01
Regulación de corriente senoidal en convertidores en fuente de tensión es un aspecto fundamental para lograr un alto nivel de rendimiento en una gran variedad de aplicaciones, como pueden ser accionamientos de motores eléctricos, filtros activos de potencia, turbinas eólicas, inversores fotovoltaicos o rectificadores activos. Uno de los tipos de reguladores de corriente más extendidos son los controladores resonantes, que consiguen error nulo en régimen permanente a determinadas frecuenci...
Intelligent Optimize Design of LCL Filter for Three-Phase Voltage-Source PWM Rectifier
DEFF Research Database (Denmark)
Sun, Wei; Chen, Zhe; Wu, Xiaojie
2009-01-01
Compared to traditional L filter, a LCL filter is more effective on reducing harmonic distortion at switch frequency. So it is important to choose the LCL filter parameters to achieve good filtering effect. This paper introduces some traditional design methods. Design of a LCL filter by genetic...... algorithm (GA) and particle swam optimization (PSO) are presented in this paper and comparison of the two intelligent optimization. Simulation result and calculate data are provided to prove that intelligent optimization are more effective and simple than traditional methods....
Feedforward Synchronised PWM for Adjustable Speed AC Drives with Different Control Modes
DEFF Research Database (Denmark)
Oleschuk, Valentin; Blaabjerg, Frede; Jensen, Flemming Buus
2002-01-01
This paper presents a novel method of direct synchronised pulswidth modulation (PWM) for three-phase voltage source inverters, feeding induction motors with different control regimes. It is based on the universal algorithm with either simplified algebraic or accurate trigonometric control functions...
DEFF Research Database (Denmark)
Blaabjerg, Frede; Aquila, A. Dell; Liserre, Marco;
2004-01-01
A systematic approach to study dc/ac and ac/dc converters without the use of synchronous transformation is proposed. The use of a frequency-shift technique allows a straightforward analysis of single-phase and three-phase systems. The study of dc/ac and of ac/dc converters is reported to the study...... of dc/dc converters via a 50 Hz frequency-shift. The input admittance is calculated and measured for two study examples (a three-phase active rectifier and a single-phase photovoltaic inverter). These examples show that the purpose of a well designed controller for grid-connected converters...
Directory of Open Access Journals (Sweden)
Mechouma Rabiaa
2014-01-01
Full Text Available In recent years, power demand of industrial applications has increased significantly reaching some megawatts. The use of multilevel converters for applications of medium and high powers is proposed as a solution to drawback semiconductor technology. A multilevel converter not only achieves high power ratings, but also enables the use of renewable energy sources. Renewable energy sources such as photovoltaic can be easily interfaced to a multilevel converter system for a high power application. This paper presents the simulation study in Matlab/Simulink of a grid connected photovoltaic three phase Neutral Point Clamped (NPC inverter with DC/DC boost converter for constant and variable solar radiation.
Institute of Scientific and Technical Information of China (English)
刘波; 金昊
2014-01-01
由于双 P WM变换器的永磁直驱风电系统在常规控制策略下，当风速变化时，存在直流侧电容电压波动较大、控制系统的响应速度较慢的现象，提出有功功率前馈补偿协调控制策略。将发电机侧瞬时有功功率作为前馈信号送到网侧变换器功率控制内环，对有功功率变化扰动直接调节，协调控制双P WM变换器两侧有功功率，实现瞬时有功功率平衡，有效抑制直流侧电压的波动，同时加快控制系统的响应速度。在此基础上，在前馈控制通道中加入补偿环节，进一步提高前馈控制效果。并通过对比仿真，验证了控制策略的正确性和有效性。%Considering the fact that in conventional control strategy,the DC side capacitor voltage of dual PWM converter-based direct-drive permanent-magnet wind power system has lager fluctuation and slower con-trol system response,a coordinated control strategy of active power feed-forward compensation was proposed, in which,having motor-side instantaneous active power sent to the grid-side converter power control loop as a feed-forward signal to regulate active power change disturbance directly and to control active power of dual PWM converter on both sides coordinately so that the instantaneous active power can be balanced and the DC bus voltage fluctuation can be inhibited effectively,as well as the control system response can be accelerated. On this basis,a compensation step added in the feed-forward control channel can further improve feed-forward control.Simulation and comparison results verify both correctness and effectiveness of this control strategy.
Energy Technology Data Exchange (ETDEWEB)
She, Xu; Chokhawala, Rahul Shantilal; Zhou, Rui; Zhang, Di; Sommerer, Timothy John; Bray, James William
2016-12-13
A voltage source converter based high-voltage direct-current (HVDC) transmission system includes a voltage source converter (VSC)-based power converter channel. The VSC-based power converter channel includes an AC-DC converter and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and a DC-AC inverter include at least one gas tube switching device coupled in electrical anti-parallel with a respective gas tube diode. The VSC-based power converter channel includes a commutating circuit communicatively coupled to one or more of the at least one gas tube switching devices. The commutating circuit is configured to "switch on" a respective one of the one or more gas tube switching devices during a first portion of an operational cycle and "switch off" the respective one of the one or more gas tube switching devices during a second portion of the operational cycle.
A novel design methodology for low pass filter stage of a voltage source inverter
Indian Academy of Sciences (India)
ANIRBAN DE
2016-05-01
A low pass filter, an invariable constituent of a PWM based voltage source inverter, poses several challenges in its design. With a higher rating of the inverter, the volume as well as the cost of the components increases. With time, the filter design has evolved from the simpler first order filter to higher orders, the most popular being the third order LCL filters. Though the attenuation of high frequency components, offered by the higher order filters, has resulted in improved efficiency, the inherent instability of the higher order filter systemsrequires complex controls for proper functioning. Keeping this in mind, the paper describes the design methodology of a second order LC filter system based on certain performance indices that reflect the ratings of the components.
Institute of Scientific and Technical Information of China (English)
李宁; 王跃; 王兆安
2014-01-01
In modulation strategies for three-level neutral point clamped (NPC) converters the double modulation wave carrier-based PWM (DMWPWM) strategy is such a modulation strategy, by which the neutral point voltage control under the entire modulation index and full power factor can be achieved. Firstly, the basic principle of existing DMWPWM strategies are analyzed and the relation between modulation wave in DMWPWM and that in traditional sinusoidal pulse width modulation (SPWM) is analyzed, and on this basis a DMWPWM strategy for three-level NPC converter is proposed;secondly, in the aspects of total harmonic distortion (THD) characteristic of output phase voltage, DC voltage utilization and switching loss of the device the proposed DMWPWM strategy is compared with traditional SPWM strategy to further expound the features of the proposed method. The correctness of theoretical analysis is validated by results from simulation and experiments.%三电平NPC变流器的调制策略中，双调制波载波调制策略(double modulation wave carrier-based PWM ， DMWPWM)是一种可以实现全调制度和全功率因数中点电压无波动的调制策略。首先分析了已有DMWPWM策略的基本原理，推导了DMWPWM策略调制波与传统SPWM策略调制波的关系，在此基础上提出了应用于三电平NPC变流器的DMWPWM策略。然后，从输出相电压总谐波畸变率(total harmonic distortion，THD)特性、直流电压利用率以及器件开关损耗三方面对新型DMWPWM策略与传统正弦脉冲宽度调制(sinusoidal pulse width modulation，SPWM)策略进行对比，进一步阐明了所提方法特点。仿真和实验结果验证了理论分析的正确性。
Relationships between Harmonic Characteristics and Different Types of Voltage Source
Directory of Open Access Journals (Sweden)
Yusniati Yusniati
2012-06-01
Full Text Available This paper discusses about harmonic characteristics due to different types of voltage sources. Usually, the voltage source is sinusoidal. But in actual condition the load that receive voltage sources through the elements where the output voltage of element as input to the load is not pure sinusoidal, for example voltage source at (PCC between transformer and linear load and nonlinear load. This research has been done with Schhafner Power Quality Analyzer and PM300 Power Quality Analyzer, was focused to all harmonic characteristics as power, voltage, current, power factor (p.f., Harmonic Distortion, and harmonic energy losses cost. The load is Induction Motor with Adjustable Speed Drive (ASD because the Induction Motor with Adjustable Speed Drive (ASD is one of electronic device causes harmonics. The voltage sources in this research are sine wave, square wave and harmonic order combinations of 3rd, 5th and 7th which can create from Schhafner Power Quality Analyzer.
Relationships between Harmonic Characteristics and Different Types of Voltage Source
Directory of Open Access Journals (Sweden)
Syafruddin H
2012-06-01
Full Text Available This paper discusses about harmonic characteristics due to different types of voltage sources. Usually, the voltage source is sinusoidal. But in actual condition the load that receive voltage sources through the elements where the output voltage of element as input to the load is not pure sinusoidal, for example voltage source at (PCC between transformer and linear load and nonlinear load. This research has been done with Schhafner Power Quality Analyzer and PM300 Power Quality Analyzer, was focused to all harmonic characteristics as power, voltage, current, power factor (p.f., Harmonic Distortion, and harmonic energy losses cost. The load is Induction Motor with Adjustable Speed Drive (ASD because the Induction Motor with Adjustable Speed Drive (ASD is one of electronic device causes harmonics. The voltage sources in this research are sine wave, square wave and harmonic order combinations of 3rd, 5th and 7th which can create from Schhafner Power Quality Analyzer.
Round, Simon; Schafmeister, Frank; Heldwein, Marcelo; Pereira, Eduardo; Serpa, Leonardo; Kolar, Johann
This paper undertakes a comparison of the very sparse matrix converter (VSMC) and the back-to-back voltage DC-link converter (BBC) for a permanent magnetic synchronous motor drive application. The VSMC has the same functionality as the conventional matrix converter but a reduced number of switches and lower control complexity. The two converters are designed, using the same IGBT power modules, with a switching frequency of 40kHz and a thermal rating of 6.8kW at an ambient temperature of 45°C. From the design, the volume of the VSMC is 2.3 liters and is half that of the BBC. The efficiency for the VSMC at full load is 94.5% compared to 92% for the BBC. At very low output frequencies the output current of the VSMC can be increased by 25% above nominal compared to a 54% decrease for the BBC. Overall the VSMC offers advantages in volume and efficiency for motor drive applications requiring switching frequencies above 10kHz.
DEFF Research Database (Denmark)
Deng, Fujin; Chen, Zhe
2015-01-01
The modular multilevel converter (MMC) is attractive for medium- and high-power applications because of its high modularity, availability, and power quality. In this paper, the current ripple on the dc link of the three-phase MMC derived from the phase-shifted carrier-based pulse-width modulation...
Application of film capacitor in DC-link of wind power PWM converter%薄膜电容器在风电PWM变流器直流环节的应用
Institute of Scientific and Technical Information of China (English)
辛倩; 林资旭; 赵斌; 许洪华
2011-01-01
An appropriate film capacitor was selected to take the place of aluminum electrolytic capacitor apply in DC-link of the PWM converter system through the calculation of capacitance and ripple current. The feasibility of the principle of selecting the minimum capacitance is proven by using improved control strategy in Matlab simulation. The film capacitor, which was selected based on the selection principle performed well in DC-link of 2MW DFIG system.%通过计算变流器直流环节的电容量和纹波电流,选取合适的薄膜电容器应用于风电变流器直流环节,取代铝电解电容器.利用Matlab仿真软件,使用改进的控制策略,验证了最小电容量选取原则的可行性.将此原则应用于2 MW风电用双馈变流器直流环节薄膜电容器的选型,取得了较为理想的效果.
Enhanced control of DFIG-used back-to-back PWM VSC under unbalanced grid voltage conditions
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
This paper presents a unified positive- and negative-sequence dual-dq dynamic model of wind-turbine driven doublyfed induction generator (DFIG) under unbalanced grid voltage conditions. Strategies for enhanced control and operation of a DFIG-used back-to-back (BTB) PWM voltage source converter (VSC) are proposed. The modified control design for the grid-side converter in the stationary αβ frames diminishes the amplitude of DC-link voltage ripples of twice the grid frequency, and the two proposed control targets for the rotor-side converter are alternatively achieved, which, as a result, improve the fault-ride through (FRT) capability of the DFIG based wind power generation systems during unbalanced network supply. A complete unbalanced control scheme with both grid- and rotor-side converters included is designed. Finally, simulation was carried out on a 1.5 MW wind-turbine driven DFIG system and the validity of the developed unified model and the feasibility of the proposed control strategies are all confirmed by the simulated results.
Institute of Scientific and Technical Information of China (English)
杨博; 杜海江; 吕剑刚; 孙航
2014-01-01
基于功率变换器脉宽调制(pulse width modulation PWM)技术实现通信功能，就是在保证对功率变换器输出功率进行控制的同时，实现设备间的有效通信。文章以光伏阵列发电系统为应用对象，设计了相应的通信方法实现系统中设备之间的通信：改变载波频率对信源信号进行调制，生成PWM开关驱动信号作为信源信号的调制信号，同时驱动开关管控制功率传输；解调时，提出以电流信号作为检测对象，设计了幅值阈值判定法和能量值阈值判定法确定信源信号的起始码元及后续码元，最终实现同一光伏组串内的不同光伏组件之间、以及组件与阵列通信终端之间的有效通信。仿真设计相应的系统参数和工况来模拟光伏阵列系统的通信过程，并在通信的同时改变占空比实现功率调节，结果表明了所提方法的有效性。%The essence of communication function based on pulse width modulation (PWM) technology of power converter is to implement effective communication among devices while the output power control of power inverter is ensured. Taking the generation system composed of photovoltaic cell arrays as the object to apply the proposed communication method, a corresponding method for the communication among devices in PV array generation system is designed, that is, the source signal is modulated by changing carrier frequency to generate the driving signal of PWM switch, which is taken as the modulation signal of source signal;for the demodulation, it is proposed to take the current signal as the detected object, and the amplitude threshold based judgment method and the energy threshold based judgment method are designed to determine the initial code element and subsequent code elements, eventually the effective communication among different PV modules in the same PV module string and that among modules and array communication terminals are realized. Corresponding
Nakamura, Mantaro; Yamazaki, Takayuki; Fujii, Yuma; Ahmed, Tarek; Nakaoka, Mutsuo
This paper proposes a new circuit topology of the three-phase soft switching PWM inverter and PFC converter using IGBT power modules, which has the improved active auxiliary switch and edge resonant bridge leg-commutation-link soft-switching snubber circuit with pulse current regenerative feedback loop as compared with the typical auxiliary resonant pole snubber discussed previously. This three-phase soft switching PWM double converter is more suitable and acceptable for a large capacity uninterruptible power supply, PFC converter, utility-interactive bi-directional converter and so forth. In this paper, the soft switching operation and optimum circuit design of the novel type active auxiliary edge resonant bridge leg commutation link snubber treated here are described for high power applications. Both the main active power switches and the auxiliary active power switches achieve soft switching under the principles of ZVS or ZCS in this three-phase inverter switching. This three-phase soft switching commutation scheme can effectively minimize the switching surge related electromagnetic noise and the switching power losses of the power semiconductor devices; IGBTs and modules used here. This three-phase inverter and rectifier coupled double converter system does not need any sensing circuit and its peripheral logic control circuits to detect the voltage or the current and does not require any unwanted chemical electrolytic capacitor to make the neutral point of the DC power supply voltage source. The performances of this power conditioner are proved on the basis of the experimental and simulation results. Because the power semiconductor switches (IGBT module packages) have the relation of the trade-off in the switching fall time and tail current interval characteristics as well as the conductive saturation voltage characteristics, this three-phase soft-switching PWM double converter can perform to improve actual efficiency in the output power ranges with a trench
Self oscillating PWM modulators, a topological comparison
DEFF Research Database (Denmark)
Poulsen, Søren; Andersen, Michael Andreas E.
2004-01-01
or fs/ð range respectively, where fs is the switching frequency of the converter. For some applications this will require unacceptable high switching frequency to achieve enough control loop bandwidth for the desired dynamic performance. With self oscillating modulators, the open loop bandwidth is equal...... to fs which makes this type of modulators an excellent choice for a wide range of applications. Self oscillating PWM modulators can be made in a number of ways, either as voltage or current mode modulators, and the self oscillating behavior can be achieved either by using hysteresis control......High precision control of the output voltage or current of a switch mode converter with fast response is required for a number of applications. Dependent on the type of application, the desired precision and transient response can be difficult, if not impossible, to achieve with standard PWM...
Optimal condition of memristance enhancement circuit using external voltage source
Directory of Open Access Journals (Sweden)
Hiroya Tanaka
2014-05-01
Full Text Available Memristor provides nonlinear response in the current-voltage characteristic and the memristance is modulated using an external voltage source. We point out by solving nonlinear equations that an optimal condition of the external voltage source exists for maximizing the memristance in such modulation scheme. We introduce a linear function to describe the nonlinear time response and derive an important design guideline; a constant ratio of the frequency to the amplitude of the external voltage source maximizes the memristance. The analysis completely accounts for the memristance behavior.
Perra, Andre
1992-04-01
The use of pulse-width-modulated (PWM) inverter technology by on-line uninterruptible power supplies (UPSs) of 250 VA-750 kVA rating improves transient performance, lowers harmonic distortion, and enhances nonlinear load performance. An account is presently given of the means employed for optimization of a PWM inverter used in a multi-kHz UPS. By using computer modeling to optimize the feedback control loop, the best level of response was furnished, while minimizing switching losses and achieving the highest level of efficiency.
DEFF Research Database (Denmark)
Wang, Songcen; Teodorescu, Remus; Máthé, Lászlo
2015-01-01
This paper focuses on modeling and SOC (State of Charge) balancing control of lithium-ion battery energy storage system based on cascaded multilevel converter for both grid integration and electric vehicle propulsion applications. The equivalent electrical circuit model of lithium-ion battery...... is adopted to control active power and reactive power independently, and the zero-sequence voltage injection and a sorting and select algorithm are employed for SOC balancing control. The simulation results have been carried out with PLECS Simulation Software and are presented to validate the SOC control...
Analysis and Simulation of a High Performance Quasi Resonant PWM Inverter for Solar Power Generation
Institute of Scientific and Technical Information of China (English)
Yun-Parn Lee; Yu-Huang Lin; Yu-Lun Lin
2016-01-01
A quasi resonant pulse width modulation (PWM) inverter is used in a solar power system to convert the solar panel and battery charger’s direct current (DC) output to alternating current (AC). Although much has been published about DC to AC PWM inverters, none of the previous work has shown modeling and simulation results for DC to AC inverters. In this study, we suggest a new topology for a quasi resonant PWM inverter. Experimental results are also presented.
Synchronized Scheme of Continuous Space-Vector PWM with the Real-Time Control Algorithms
DEFF Research Database (Denmark)
Oleschuk, V.; Blaabjerg, Frede
2004-01-01
This paper describes in details the basic peculiarities of a new method of feedforward synchronous pulsewidth modulation (PWM) of three-phase voltage source inverters for adjustable speed ac drives. It is applied to a continuous scheme of voltage space vector modulation. The method is based...... on a representation of the pulse patterns as a function of the fundamental and switching frequencies of the drive system. Accurate trigonometric algorithms of vector PWM have been analysed, and also compared with the algebraic ones based on linear approximation of the durations of active switching states from...
A COMPREHENSIVE ANALYSIS OF SPACE VECTOR PWM TECHNIQUE BASED ON PLACEMENT OF ZERO-SPACE VECTOR
Directory of Open Access Journals (Sweden)
G.SAMBASIVA RAO,
2011-04-01
Full Text Available In this paper, the effect of placement of zero-space vector for the implementation of space vector based Pulse Width Modulation techniques for 3-phase Voltage Source Inverter is presented. Several pulse width modulation (PWM control strategies have been proposed for 3-phase voltage source inverter (VSI in the past. It is known that space vector modulation (SVM offers a degree of freedom in its implementation with regard to the placement of the zero-space vector. Apart from constructing a consistent theoretical framework, simulation results with conventional continuous SVM and various discontinuous SVM techniques are presented and all the cases are compared in this paper.
Distributed control system for parallel-connected DC boost converters
Energy Technology Data Exchange (ETDEWEB)
Goldsmith, Steven
2017-08-15
The disclosed invention is a distributed control system for operating a DC bus fed by disparate DC power sources that service a known or unknown load. The voltage sources vary in v-i characteristics and have time-varying, maximum supply capacities. Each source is connected to the bus via a boost converter, which may have different dynamic characteristics and power transfer capacities, but are controlled through PWM. The invention tracks the time-varying power sources and apportions their power contribution while maintaining the DC bus voltage within the specifications. A central digital controller solves the steady-state system for the optimal duty cycle settings that achieve a desired power supply apportionment scheme for a known or predictable DC load. A distributed networked control system is derived from the central system that utilizes communications among controllers to compute a shared estimate of the unknown time-varying load through shared bus current measurements and bus voltage measurements.
EMC Increasing of PWM Rectifier in Comparison with Classical Rectifier
Directory of Open Access Journals (Sweden)
R. Dolecek
2008-12-01
Full Text Available Pulse width modulated rectifier is a very popular topic nowadays. The modern industrial production demands continuous and lossless conversion of electrical energy parameters. This need leads to wide spread of power semiconductor converters. The rapid development in power electronics and microprocessor technology enables to apply sophisticated control methods that eliminate negative side effects of the power converters on the supply network. The phase controlled thyristor rectifiers overload the supply network with higher harmonics and reactive power consumption. That is why the PWM rectifier is being examined. In comparison with the phase controlled rectifier it can be controlled to consume nearly sinusoidal current with power factor equal to unity. Another advantage is its capability of energy recuperation. The PWM rectifier can assert itself for its good behavior in many applications, for example as an input rectifier in indirect frequency converter, or in traction. Traction vehicles equipped with PWM rectifier do not consume reactive power, do not load the supply network with higher harmonics, and the recuperation is possible. The paper deals with the PWM rectifier functional model realization and examination. Electromagnetic compatibility of PWM rectifier and classical phase controlled rectifier is compared on the basis of the input current harmonic analysis.
Nongrounded Common-Mode Equivalent Circuit for Brushless DC Motor Driven by PWM Inverter
Maetani, Tatsuo; Isomura, Yoshinori; Watanabe, Akihiko; Iimori, Kenichi; Morimoto, Shigeo
This paper describes nongrounded common-mode equivalent circuit for a motor driven by a voltage-source PWM inverter. When the capacitance of the rotor was small, the phenomenon that polarity of the common mode voltage and shaft voltage reversed was observed. In order to model this phenomenon, the bridge type equivalent circuit is proposed. It is verified with the calculation and experiment that shaft voltage values and polarity are accurately calculated with the proposed equivalent circuit.
Diode-Assisted Buck-Boost Voltage-Source Inverters
DEFF Research Database (Denmark)
Gao, Feng; Loh, Poh Chiang; Teodorescu, Remus;
2009-01-01
This paper proposes a number of diode-assisted buck-boost voltage-source inverters with a unique X-shaped diode-capacitor network inserted between the inverter circuitry and dc source for producing a voltage gain that is comparatively higher than those of other buck-boost conversion techniques...
DEFF Research Database (Denmark)
Federico, de Bosio; de Sousa Ribeiro, Luiz Antonio; Freijedo Fernandez, Francisco Daniel
2017-01-01
and Smith predictor design, respectively, are obtained. Subsequently, the voltage regulator is also designed for a wide bandwidth, which permits the inclusion of resonant filters for the steady-state mitigation of odd harmonics at nonlinear unbalance load terminals. Discrete-time domain implementation......The decoupling of the capacitor voltage and inductor current has been shown to improve significantly the dynamic performance of voltage source inverters in standalone applications. However, the computation and PWM delays still limit the achievable bandwidth. In this paper a discrete-time domain...
Institute of Scientific and Technical Information of China (English)
王建华; 张方华; 龚春英
2014-01-01
提出了双向功率流动场合的PWM Switch模型,同时选取典型的Buck/Boost双向变换器作为评估平台.小信号分析结果表明,Buck/Boost双向直直变换器通过仅控制Buck模式主控管可以对电池充放电模式进行切换.其提供了对变换器稳态及动态性能研究的一种快速仿真方法.基于改进PWM Switch模型及器件级电路的详尽仿真对比验证了模型的精确性.
DEFF Research Database (Denmark)
Mathe, Laszlo; Lungeanu, Florin; Rasmussen, Peter Omand;
2010-01-01
This paper presents a new fixed carrier frequency random PWM method, where a new type of carrier wave is proposed for modulation. Based on the measurements, it is shown that the spread effect of the discrete components from the motor current spectra is very effective independent of the modulation...... index. The flat motor current spectrum generates an acoustical noise close to the white noise, which may improve the acoustical performance of the drive. The new carrier wave is easy to implement digitally, without employing any external circuits. The modulation method can be used in open, as well...
Directory of Open Access Journals (Sweden)
Abolfazl Halavei Niasar
2013-02-01
Full Text Available Induction motors offer many advantages tools, and therefore are becoming very popular industrially and commercially. This paper presents the implementation of Xmega microcontroller based PWM inverter controlled of four-switch three phase voltage source inverter (FSTPI fed induction motor drive. The reduction of the number of power switches from six to four improves the cost effectiveness, volume-compactness and reliability of the three phase inverters in addition to less complexity of control algorithms and reduced interface circuits. Simulation and experimental work are carried out and results presented to demonstrate the feasibility of the proposed approach. Simulation is carried out using SIMULINK and in experimental work, a prototype model is built to verify the simulation results. XMEGA microcontroller (XMEGA64A3 is used to generate the PWM pulses with a new algorithm for FSTPI to drive a 5 hp, 3-phase induction motor. Experimental and simulation results show that the proposed drive system provides a fast speed response and good disturbance rejection capability.
Border Collision of Three-Phase Voltage-Source Inverter System with Interacting Loads
Li, Zhen; Liu, Bin; Li, Yining; Wong, Siu-Chung; Liu, Xiangdong; Huang, Yuehui
As a commercial interface, three-phase voltage-source inverters (VSI) are commonly equipped for energy conversion to export DC power from most distributed generation (DG) to the AC utility. Not only do voltage-source converters take charge of converting the power to the loads but support the grid voltage at the point of common connection (PCC) as well, which is dependent on the condition of the grid-connected loads. This paper explores the border collision and its interacting mechanism among the VSI, resistive interacting loads and grids, which manifests as the alternating emergence of the inverting and rectifying operations, where the normal operation is terminated and a new one is assumed. Their mutual effect on the power quality under investigation will cause the circuital stability issue and further deteriorate the voltage regulation capability of VSI by dramatically raising the grid voltage harmonics. It is found in a design-oriented view that the border collision operation will be induced within the unsuitable parameter space with respect to transmission lines of AC grid, resistive loads and internal resistance of VSI. The physical phenomenon is also identified by the theoretical analysis. With numerical simulations for various circuit conditions, the corresponding bifurcation boundaries are collected, where the stability of the system is lost via border collision.
Institute of Scientific and Technical Information of China (English)
屈克庆; 陈国呈; 孙承波
2004-01-01
This paper presents a novel current feedforward control strategy for a three-phase pulse-width modulation (PWM) DC voltage-type converter based on phase and amplitude control (PAC).With right-angle triangle relation of phasors and principle of conservation of energy, a phasor adjustment method and the relevant low-frequency mathematical model of the system are analyzed in detail, both in rectification and regeneration modes for the converter, are discussed.For improving the traditional PAC dynamic performance, variable load current is detected indirectly by the change of the DC voltage, which is fed to the control system as an additional control variable to generate modulation index and phase angle.Also, the algorithm is derived and the system principle is introduced.Experimental results from a 3 kw laboratory device are included to demonstrate the effectiveness of the proposed control strategy.
Neural network based PWM AC chopper fed induction motor drive
Directory of Open Access Journals (Sweden)
Venkatesan Jamuna
2009-01-01
Full Text Available In this paper, a new Simulink model for a neural network controlled PWM AC chopper fed single phase induction motor is proposed. Closed loop speed control is achieved using a neural network controller. To maintain a constant fluid flow with a variation in pressure head, drives like fan and pump are operated with closed loop speed control. The need to improve the quality and reliability of the drive circuit has increased because of the growing demand for improving the performance of motor drives. With the increased availability of MOSFET's and IGBT's, PWM converters can be used efficiently in low and medium power applications. From the simulation studies, it is seen that the PWM AC chopper has a better harmonic spectrum and lesser copper loss than the Phase controlled AC chopper. It is observed that the drive system with the proposed model produces better dynamic performance, reduced overshoot and fast transient response. .
Directory of Open Access Journals (Sweden)
F. J. De la Hidalga-W
2013-01-01
Full Text Available This work shows that the direct PWM output electric signal, with a duty cycle controlled by light intensity, can beobtained using a circuit containing a saw-tooth voltage generator connected in series with a dc voltage source and ametal (semitransparent gate oxide semiconductor capacitor (MOS-C.The internal PWM signal conversion occurs by the use of non-equilibrium physical processes in the semiconductorsubstrate of the MOS-C. The 10-20 V amplitude limited square PWM output signal is obtained by the amplification ofthe sensor signal with a standard 60 dB transimpedance amplifier. The amplified output signal presents positive andnegative PWM waveforms that can be easily separated using diodes. The duty of the positive part is proportional tothe light intensity, whereas the negative part is inversely proportional to the intensity. The frequency operating rangeof this proposed instrument varies from 1 Hz to a few kilohertz. The duty cycle of the PWM output signal varies from2% to 98% when the incident light intensity varies in the microwatts range. These new transducers or sensors couldbe useful for automatic control, robotic applications, dimmer systems, feedback electronic systems, and non-contactoptical position sensing for nulling and centering measurements.
DEFF Research Database (Denmark)
Lar, Ionut Andrei; Radulescu, Mircea; Ritchie, Ewen
2012-01-01
A comparison between two current control methods of grid side inverter, PI current control and Robust Forward control is made. PI control is implemented in d-q synchronous frame while Forward is implemented in abc stationary frames.The report contains both simulations and experimental test wich...... were made at a reduced scale ( 2.2 kW). The constant power test showed that both method have good results which can respect existing grid codes. The constant power test showed that both method have good results which can respect existing grid codes....
Directory of Open Access Journals (Sweden)
Hong-yu Zhu
2013-01-01
Full Text Available Broken rotor bars fault detection in inverter-fed squirrel cage induction motors is still as difficult as the dynamics introduced by the control system or the dynamically changing excitation (stator frequency. This paper introduces a novel fault diagnosis techniques using motor current signature analysis (MCSA to solve the problems. Switching function concept and frequency modulation theory are firstly used to model fault current signal. The competency of the amplitude of the sideband components at frequencies (1±2sfs as indices for broken bars recognition is subsequently studied in the controlled motor via open-loop constant voltage/frequency control method. The proposed techniques are composed of five modules of anti-aliasing signal acquisition, optimal-slip-estimation based on torque-speed characteristic curve of squirrel cage motor with different load types, fault characteristic frequency determination, nonparametric spectrum estimation, and fault identification for achieving MCSA efficiently. Experimental and simulation results obtained on 3 kW three-phase squirrel-cage induction motors show that the model and the proposed techniques are effective and accurate.
DEFF Research Database (Denmark)
Lar, Ionut Andrei; Radulescu, Mircea; Ritchie, Ewen
2012-01-01
A comparison between two current control methods of grid side inverter, PI current control and Robust Forward control is made. PI control is implemented in d-q synchronous frame while Forward is implemented in abc stationary frames.The report contains both simulations and experimental test wich w...
Energy Technology Data Exchange (ETDEWEB)
Aime, M.
2003-11-15
Thanks to the technological progress achieved in the field of power electronics, the use of static converters has spread to new applications. In particular, some applications such as active filtering or the supply of special AC machines require power converters having good dynamic performances. The subject of this thesis is to evaluate systematically the dynamic performances of multi-cell converters, and then to optimize these performances. This document is organized in four chapters. The first one summarizes the main multilevel converter structures, and some control strategies dedicated to these structures. The second chapter presents the evaluation criteria chosen to quantify the dynamic performances of static converters. These criteria are then used to compare the performances obtained with two different PWM strategies. An optimized strategy which results from a trade-off between the two former strategies is then introduced. The third chapter shows a new control strategy of multi-cell voltage source converters. This new strategy enables to control the peak current at a fixed switching frequency. The operation of this controller is explained, and the results obtained by digital simulations are presented and discussed. The fourth chapter deals with the experimental achievement of the peak current control. In particular, the implementation of the control algorithm within a FPGA is demonstrated. Finally, the conclusion of this thesis presents some orientations for further developments, in order to improve the current control strategy and to widen its field of applications. (author)
Design of New Single-phase Multilevel Voltage Source Inverter
Directory of Open Access Journals (Sweden)
Rasoul Shalchi Alishah
2014-07-01
Full Text Available Multilevel inverters with more number of levels can produce high quality voltage waveforms. In this paper, a new single-phase structure for multilevel voltage source inverter is proposed which can generate a large number of levels with reduced number of IGBTs, gate driver circuits and diodes. Three algorithms for determination of dc voltage sources’ magnitudes are presented which provide odd and even levels at the output voltage waveform. A comparison is presented between proposed multilevel inverter and conventional cascade topology. The proposed topology is analyzed by the experimental and simulation results.
On the Well-posedness of the PWM Control System
Institute of Scientific and Technical Information of China (English)
FAN Qi-fu; SHI Song-jiao
2006-01-01
One of the basic issues in the study of hybrid systems is the well-posedness (existence and uniqueness of solutions) problem of discontinuous dynamical systems.This paper addresses this problem for a class of piecewise affine discontinuous systems with affine inequalities such as systems with pulse-width modulator under the definition lexicographic inequalities and the smooth continuation property of solutions.Furthermore,it is clear that when carrier signal h(t)=0,closed-loop pulse-width modulation (PWM) DC-DC converters are not well posed,and when some condition is satisfied,the closed-loop PWM DC-DC converters with a P controller are well posed.
Review of multilevel voltage source inverter topologies and control schemes
Energy Technology Data Exchange (ETDEWEB)
Colak, Ilhami [Department of Electrical Education, Faculty of Technical Education, Gazi University, Besevler, Ankara 06500 (Turkey); Kabalci, Ersan, E-mail: kabalci@nevsehir.edu.t [Department of Technical Programs, Vocational Collage of Haci Bektas, Nevsehir University, Hacibektas, Nevsehir 50800 (Turkey); Bayindir, Ramazan [Department of Electrical Education, Faculty of Technical Education, Gazi University, Besevler, Ankara 06500 (Turkey)
2011-02-15
In this study, the most common multilevel inverter topologies and control schemes have been reviewed. Multilevel inverter topologies (MLIs) are increasingly being used in medium and high power applications due to their many advantages such as low power dissipation on power switches, low harmonic contents and low electromagnetic interference (EMI) outputs. The selected switching technique to control the inverter will also have an effective role on harmonic elimination while generating the ideal output voltage. Intensive studies have been performed on carrier-based, sinusoidal, space vector and sigma delta PWM methods in open loop control of inverters. The selection of topology and control techniques may vary according to power demands of inverter. This paper and review results constitute a useful basis for matching of inverter topology and the best control scheme according to various application areas.
OPTIMAL PWM BASED ON REAL—TIME SOLUTION WITH NEURAL NETWORK
Institute of Scientific and Technical Information of China (English)
ShenZhongting; YanYangguang
2002-01-01
A novel concept of neural network based control in pulse-width modulation(PWM)voltage source inverters is presented.On the one hand,the optimal switching an-gles are obtained in real time by the neural network based controller；on the other hand,the output voltage is ad-justed to fit the expected value by neural network when input voltage or loads change.The structure of neural network is simple and easy to be realized by DSP hard-ware system.No large memory used for the existing opti-mal PWM schemes is required in the system.Theoreticalanlysis of the proposed so-called sparse neural network is provided,and the stability of the system is proved.Un-der the control of neural network the error of output volt-age descends sharply,and the system outputs ac voltage with high precision.
DC to DC converters: operation; Hacheurs: fonctionnement
Energy Technology Data Exchange (ETDEWEB)
Bernot, F. [Ecole d' Ingenieurs de Tours, 37 (France)
2002-05-01
This article deals with pulse width modulation (PWM) and pulse position modulation (PPM) DC to DC converters. A tri-phase PWM converter is made of 6 simple DC/DC converters grouped together into 3 reversible converters of the same type: 1 - single-quadrant voltage lowering converters (hydraulic analogy, study with ideal elements, full scheme with input and output filters); 2 - single-quadrant voltage raising converters (hydraulic analogy, operation); 3 - two quadrants reversible converters (structure construction, quadrants of operation, reversible converter connected to a DC motor); 4 - four-quadrants reversible converters; 5 - other converters structure (current converters and converters with intermediate storage, asymmetrical converters, converters with capacitive storage, insulated converters, resonating converters, status); 6 - conclusion. (J.S.)
Grid control strategy of wind turbine based on double voltage source rectifier%基于双VSR的风电机组并网控制策略
Institute of Scientific and Technical Information of China (English)
葛俊旭; 李鑫; 童水光; 吴德忠; 田志刚; 王鹏
2011-01-01
针对兆瓦级永磁同步发电机组并网的控制要求,基于三相电压型脉宽调制(PWM)整流器的数学模型,重点研究了直接电流控制双闭环级联结构的三相电压型PWM整流器和基于SVPWM的三相电压型PWM整流器的控制系统设计,提出基于双电压型PWM整流器(VSR)的风力发电机组的并网控制策略,并建立该控制策略的等效电路模型.通过对该并网控制策略等效电路模型的仿真分析,验证了PWM整流器的升压整流特性;同时,该等效电路输出的三相交流相电流总谐波畸变率仅为1.64%,电流波形正弦度良好.仿真结果验证了该并网控制策略的可行性.%For grid control of permanent magneticm synchronous generator, according to the mathematcalmodel of three-phase voltage source rectifier, this work emphatically studied the controller design of three-phase voltage source rectifier(VSR), which has double closed-loop and cascade structure based on the direct current control, and voltage source rectifier based on space vector pulse width modulation. The grid control strategy based on double voltage source rectifier for wind turbine generators was and proposed the corresponding equivalent circuit model was established. The simulation to this grid control strategy's equivalent circuit proved the rising voltage speciality of pulse width modulation (PWM). The current's total harmonic distortion of the grid side output's three-phase AC interphase was only 1.64％, and its waveform was batter. The new control strategy was proved feasible by Simulink simulation.
Three-Phase PWM Power Conversion--The Route to Ultra High Power Density and Efficiency
Institute of Scientific and Technical Information of China (English)
J W Kolar; J Minib(o)ck; T Nussbaumer
2005-01-01
A review of three-phase PWM converter topologies which do show a low complexity/high reliability and high efficiency and power density and are therefore of main interest for a future industrial application is presented.A three-switch/level Boost-type PWM rectifier (VIENNA Rectifier),a Buck+Boost-type PWM rectifier with wide output voltage range and the AC/AC Sparse Matrix Converter concept are discussed in detail and topics to be treated in the course of further research are identified. Finally,it is shown how the aspects being relevant for the realization of highly compact converter systems could be integrated into education in the field.
OFDM-PWM scheme for visible light communications
Zhang, Tian; Ghassemlooy, Zabih; Rajbhandari, Sujan; Popoola, Wasiu O.; Guo, Shuxu
2017-02-01
In this paper, we propose an improved hybrid optical orthogonal frequency division multiplexing (O-OFDM) and pulse-width modulation (PWM) scheme for visible light communications. In this scheme, a bipolar O-OFDM signal is converted into a PWM format where the leading and trailing edges convey the frame synchronization and modulated information, respectively. The proposed scheme is insensitive to the non-linearity of the light emitting diode (LED) as LEDs are switched 'on' and 'off' between two points. Therefore, the tight requirement on the high peak-to-average-power-ratio (PAPR) in O-OFDM is no longer a major issue. The simulation and experimental results demonstrate that the proposed scheme offers an improved bit error rate performance compared to the traditional asymmetrically clipped O-OFDM (ACO-OFDM).
Institute of Scientific and Technical Information of China (English)
郑玮仪; 曾志勇; 赵荣祥
2016-01-01
对故障后并网型三相脉宽调制(pulse width modulation, PWM)变换器系统建模、矢量调制技术和系统控制策略3个方面进行详细的研究.分析容错后变换器工作原理,建立容错后电力变换器三相静止模型.该模型揭示了故障后电容中性点电压波动的固有原因.利用伏秒平衡原理,推导基于三相静止系下矢量调制方法,该方法无需复杂的三角函数运算,且具有统一的表达公式.利用电流纹波有效值对容错后矢量调制算法进行评估,以便选择电流性能良好的调制算法.为防止中性点电压偏移对系统造成的影响,提出一种基于修正故障相调制波的中性点电压偏移控制方法,保证故障后并网变换器稳定安全运行.实验结果证明,所提方法提高电流品质,实现了故障后并网变换器稳定安全运行.
Institute of Scientific and Technical Information of China (English)
池伟; 石庆均; 陈宏伟; 马智泉
2012-01-01
Aiming at the control of direct-driven wind-power system with permanent magnet synchronous generators(PMSG) based on back-to-back PWM converter, the control strategies of generator-side converter and grid-side converter were analyzed in detail, and a control strategy of pitch angle was presented. A simulation for direct-driven wind-power system with PMSG using Matlab/Simulink was implemented. The simulation results show that direct-driven wind-power system with PMSG can operate stably under different wind speed, while it can achieve maximum power point tracking for wind energy under rated wind speed and. Limit the output power of wind-power system to rating power by pitch angle control. The results prove that the proposed control strategy of pitch angle is correct and viable.%针对基于双PWM变换器的永磁直驱风电系统的控制问题,对该风电系统电机侧变换器、电网侧变换器的控制策略进行了详细的分析,提出了一种桨距角控制策略,并基于Matlab/Simulink对永磁直驱风电系统进行了仿真.仿真结果表明,永磁直驱风电系统能够在不同风速下稳定运行,在额定风速以下可实现风能的最大功率跟踪,在额定风速以上通过桨距角控制能将风机系统的功率输出限制在额定值附近.研究结果验证了所提出的桨距控制策略的可行性.
Reactive Power Compensation of a 24 MW Wind Farm using a 12-Pulse Voltage Source Converter
DEFF Research Database (Denmark)
Pedersen, Knud Ole Helgesen; Pedersen, Jørgen Kaas
1998-01-01
Integration of large wind farms in distribution and transmission systems may have severe influence on the power quality at the connection point and may also influence the voltage controlling capability of the electrical system. The purpose of the described project has been to develop and investig......Integration of large wind farms in distribution and transmission systems may have severe influence on the power quality at the connection point and may also influence the voltage controlling capability of the electrical system. The purpose of the described project has been to develop...... and investigate the use of a STATCOM by modelling and field testing an 8 MVar unit in a 24 MW wind farm....
A Review of Passive Filters for Grid-Connected Voltage Source Converters
DEFF Research Database (Denmark)
Beres, Remus Narcis; Wang, Xiongfei; Blaabjerg, Frede;
2014-01-01
of the filter also is decreased. Thus, a comparison of the filter features including the robustness towards grid impedance variation, harmonic attenuation capability and losses in the damping circuit became interesting from a practical implementation point of view. The design of the proposed filters...
DEFF Research Database (Denmark)
Kwon, Jun Bum; Wang, Xiongfei; Bak, Claus Leth;
2015-01-01
As the increasing of power electronics based systems, not only the component-based analysis but also a systematic interaction analysis with each other systems are being important. Especially studies about the stability and the harmonics interaction are critical in order to establish the required ...
Energy Technology Data Exchange (ETDEWEB)
Barbosa, Peter Mantovanelli
1993-10-01
This work introduces a new power supply by PWM, operating at constant frequency, with soft communication. The new topology uses only two active switches and absorbs the transformer leakage inductance. Besides, the soft communication takes place with no conduction loss penalty, in comparison with conventional hard switch PWM converters. Principle of operation, analysis, design and experimentation results taken from laboratory prototype rated at 400 W/48 v, 40 Khz, using IGBT are presented. (author) 10 refs., 71 figs.
Voltage source inverters for high power, variable-voltage DC power sources
Energy Technology Data Exchange (ETDEWEB)
Chen, Z. [Department of Engineering and Technology, De Montfort University, Queens Building, The Gateway, Leicester, LE1 9BH, (United Kingdom); Spooner, E. [School of Engineering, University of Durham, Science Laboratories, South Rd, Durham, DRI 3LE, (United Kingdom)
2001-09-01
The paper discusses the applications of voltage source inverter (VSI) based power electronic systems for interfacing variable-voltage DC sources to the grid. A variable-speed wind power conversion system is used for illustration, where the VSI-based interface needs to convert a variable DC voltage to a nearly constant AC voltage with high-quality power. The power control principles of VSI are described. Various system configurations and switching strategies are examined by analysis, simulation and experimental methods. It is shown that better utilisation of semiconductors and more flexible control may be achieved by using a separately controlled DC link, rather than a directly connected VSI that has to operate at a lower modulation ratio at higher power. In some cases, multipulse inverter structures may be preferred, despite higher component count, because of reduced switching losses, fault tolerance and the absence of filters. The solutions developed in the study could be applied at a different scale to other renewable energy sources, such as wave or solar photovoltaic devices. (Author)
Selection of Carrier Waveforms for PWM Inverter
Institute of Scientific and Technical Information of China (English)
陈国呈; 屈克庆; 许春雨; 孙承波
2003-01-01
In this paper the influence of different carrier waveforms upon the output characteristics of PWM inverter is described in detail. When a triangular carrier waveform is used in hard-switching PWM inverters, harmonics exist in the neighborhood of the output frequency of the inverter output voltage and current due to the dead time. The triangular carrier waveform used in soft-switching PWM inverter will cause difficulties in controlling resonance-trigger time, higher loss in the resonant circuit, and less utilization of the DC bus voltage. If a sawtooth carrier is used in hard-switching PWM inverter, there will be severe distortion in the current waveform. When sawtooth carriers with alternate positive and negative slopes are used in soft-switching PWM inverters, the resonancetrigger time is easy to control, and distortion in the output voltage and current caused by the dead time will not appear.
Operating Standby Redundant Controller to Improve Voltage Source Inverter Reliability
2007-12-01
was built with two FPGAs programmed using XILINX System Generator and ISE foundation with a discrete algorithm representing the controller...Xilinx’s System Generator after parsing % H:\\Docs\\work_files\\faculty forms\\lab development\\buck_converter\\black_box_buck.vhd 121...this_block.setTopLevelLanguage(’VHDL’); this_block.setEntityName(’code’); % System Generator has to assume that your entity has a
An Integrated Inductor for Parallel Interleaved VSCs and PWM Schemes for Flux Minimization
DEFF Research Database (Denmark)
Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Teodorescu, Remus;
2015-01-01
The interleaving of the carrier signals of the parallel Voltage Source Converters (VSCs) can reduce the harmonic content in the resultant switched output voltages. As a result, the size of the line filter inductor can be reduced. However, in addition to the line filter, an inductive filter is oft...
Power Electronic Transformer based Three-Phase PWM AC Drives
Basu, Kaushik
A Transformer is used to provide galvanic isolation and to connect systems at different voltage levels. It is one of the largest and most expensive component in most of the high voltage and high power systems. Its size is inversely proportional to the operating frequency. The central idea behind a power electronic transformer (PET) also known as solid state transformer is to reduce the size of the transformer by increasing the frequency. Power electronic converters are used to change the frequency of operation. Steady reduction in the cost of the semiconductor switches and the advent of advanced magnetic materials with very low loss density and high saturation flux density implies economic viability and feasibility of a design with high power density. Application of PET is in generation of power from renewable energy sources, especially wind and solar. Other important application include grid tied inverters, UPS e.t.c. In this thesis non-resonant, single stage, bi-directional PET is considered. The main objective of this converter is to generate adjustable speed and magnitude pulse width modulated (PWM) ac waveforms from an ac or dc grid with a high frequency ac link. The windings of a high frequency transformer contains leakage inductance. Any switching transition of the power electronic converter connecting the inductive load and the transformer requires commutation of leakage energy. Commutation by passive means results in power loss, decrease in the frequency of operation, distortion in the output voltage waveform, reduction in reliability and power density. In this work a source based partially loss-less commutation of leakage energy has been proposed. This technique also results in partial soft-switching. A series of converters with novel PWM strategies have been proposed to minimize the frequency of leakage inductance commutation. These PETs achieve most of the important features of modern PWM ac drives including 1) Input power factor correction, 2) Common
Bidirectional buck boost converter
Esser, Albert Andreas Maria
1998-03-31
A bidirectional buck boost converter and method of operating the same allows regulation of power flow between first and second voltage sources in which the voltage level at each source is subject to change and power flow is independent of relative voltage levels. In one embodiment, the converter is designed for hard switching while another embodiment implements soft switching of the switching devices. In both embodiments, first and second switching devices are serially coupled between a relatively positive terminal and a relatively negative terminal of a first voltage source with third and fourth switching devices serially coupled between a relatively positive terminal and a relatively negative terminal of a second voltage source. A free-wheeling diode is coupled, respectively, in parallel opposition with respective ones of the switching devices. An inductor is coupled between a junction of the first and second switching devices and a junction of the third and fourth switching devices. Gating pulses supplied by a gating circuit selectively enable operation of the switching devices for transferring power between the voltage sources. In the second embodiment, each switching device is shunted by a capacitor and the switching devices are operated when voltage across the device is substantially zero.
Led spectral and power characteristics under hybrid PWM/AM dimming strategy
DEFF Research Database (Denmark)
Beczkowski, Szymon; Munk-Nielsen, Stig
2010-01-01
In order to dim LEDs the pulse width modulation (PWM) or amplitude modulation (AM) dimming scheme is typically used. Previous studies show that these dimming schemes can have opposite effects on diodes peak wavelength shift. An experimental study was conducted to test the behavior of InGaN diodes...... and phosphor-converted white diodes under hybrid PWM/AM modulation. Feed forward control schemes that provide stable peak wavelength position during dimming and the ability to compensate the thermally induced color shifts and the decrease of the luminous flux are investigated....
Pulse-width modulated DC-DC power converters
Kazimierczuk, Marian K
2008-01-01
This book studies switch-mode power supplies (SMPS) in great detail. This type of converter changes an unregulated DC voltage into a high-frequency pulse-width modulated (PWM) voltage controlled by varying the duty cycle, then changes the PWM AC voltage to a regulated DC voltage at a high efficiency by rectification and filtering. Used to supply electronic circuits, this converter saves energy and space in the overall system. With concept-orientated explanations, this book offers state-of-the-art SMPS technology and promotes an understanding of the principle operations of PWM converters,
Investigation of Power Factor on Harmonic Effect due to Types of Voltage Source
Directory of Open Access Journals (Sweden)
C.B. Risnidar
2011-01-01
Full Text Available This paper discussed about power factor on harmonic effect due to types of voltage source. Usually, the voltage source is sinusoidal. But in actual condition the load that has voltage sources through the elements where the output voltage of element as input to load is not pure sinusoidal, for example at Power of Common Coupling (PCC between transformer and linear load and nonlinear load. The research has been done with Schhafner Power Quality Analyzer and was focused to power factor (p.f., Total Harmonic Distortion (THD, and harmonic energy losses cost from measurement where load is Induction motor and Adjustable Speed Drive (ASD. As voltage source in this research are sine wave, square wave and combinations of 3rd, 5th and 7th harmonic order like harmonic 313, and harmonic 357.
Investigation of Harmonic Characteristics in Printer due to Different Types of Voltage Source
Directory of Open Access Journals (Sweden)
C. Risnidar
2012-01-01
Full Text Available This paper discusses about harmonic characteristics due to different types of voltage sources. Usually, the voltage source is sinusoidal. But in actual condition the load that receives voltage sources through the elements where the output voltage of element as input to the load is not pure sinusoidal, for example voltage source at Power of Common Coupling (PCC between transformer and linear load and nonlinear load. This research has been done with Schhafner Power Quality Analyzer and PM300 Power Quality Analyzer, was focused to all harmonic characteristics as power, voltage, current, power factor (p.f., Harmonic Distortion, and harmonic energy losses cost. The load is printer because the printer is one of electronic device causes harmonics. The voltage sources in this research are sine wave, triangle wave and harmonic order combinations of 3rd, 5th and 9th. Why this research discuses voltage source for Harmonic order 3rd, 5th and 9th and don not combination of 3rd, 5th and 7th, because the combination 3rd, 5th and 9th is more complicated then combination of 3rd, 5th and 7th.
Institute of Scientific and Technical Information of China (English)
邱长青; 黄声华; 林珍君; 王正昊
2015-01-01
Based on the mathematical model of power cells in four-quadrant cascade converters, a current control strategy for PWM rectifier was proposed with the control target being the balance of the input and output instantaneous power. The complex vector PI (CVPI) regulators were introduced to track various frequency currents and decoupled control completely. CVPI regulators were proved to have better robustness than traditional regulators with the resonant frequency change. Moreover, the DC bus output current model based on Kalman filter was established to identify the current magnitude and frequency in real time. The proposed control strategy was validated by the experimental results based on the platform of power cells.%在分析四象限级联型变频器功率单元数学模型的基础上,以输入和输出瞬时有功功率平衡为控制目标,给出了PWM整流电流指令.为保证各频率电流的准确跟踪,提出了复矢量PI(complex vector PI,CVPI)调节器,实现了各频率电流的完全解耦控制,论证了CVPI调节器相比传统调节器,对谐振频率变化具有更好的鲁棒性.同时,建立了基于卡尔曼(Kalman)滤波的直流母线输出电流辨识模型,实时地辨识电流大小及其频率.构建了功率单元实验平台,对所提控制策略的正确性与可行性进行了实验验证.
适用于纹波控制型DC-DC变换器的比较器设计%Design of PWM Comparator for DC-DC Converter Based on Ripple Control
Institute of Scientific and Technical Information of China (English)
杨靖; 冯全源
2014-01-01
设计一种适用于纹波控制( Output-Ripple-Based Control)的Buck型DC-DC变换器的比较器,根据PSIM搭建的仿真模型,分析主环比较器性能对系统的影响,设计具有三级预放大的高增益,低延时,低失调电压的比较器电路,采用两种温度系数的电流补偿比较器增益,稳定增益,采用0.5μm BiCOMS工艺进行仿真验证,下降沿延时27 ns,增益123 dB,随温度最大增益变化3.2%,失调电压90μV,达到系统要求。%A kind of comparator applicable to Output-Ripple-Based Control DC-DC Converter was put forward. By using PSIM to build simulation model,and analysing the main loop comparator's performance,the influence of the system,a comparator circuit with preamplifier of high gain,low delay,low disorder voltage were designed. The two kinds of temperature coefficient of bias current are using to compensate the comparator's gain,By using 0. 5 μm BiCOMS process to simulation verification,the falling edge delay is 27 ns,gain is 123 dB,the biggest gain 3. 2%with temperature changes,offset voltage 90 μV and they all reach the system requirements.
DSP controlled power converter
Chan, CH; Pong, MH
1995-01-01
A digital controller is designed and implemented by a Digital Signal Processor (DSP) to replace the Pulse Width Modulator (PWM) and error amplifier compensation network in a two wheeler forward converter. The DSP controller is designed in three approaches: a) Discretization of analog controller - the design is based on the transfer function of the error amplifier compensation network. b) Digital PID controller design - the design is based on the general form of the pulse transfer function of ...
Study of a control strategy for grid side converter in doubly- fed wind power system
Zhu, D. J.; Tan, Z. L.; Yuan, F.; Wang, Q. Y.; Ding, M.
2016-08-01
The grid side converter is an important part of the excitation system of doubly-fed asynchronous generator used in wind power system. As a three-phase voltage source PWM converter, it can not only transfer slip power in the form of active power, but also adjust the reactive power of the grid. This paper proposed a control approach for improving its performance. In this control approach, the dc voltage is regulated by a sliding mode variable structure control scheme and current by a variable structure controller based on the input output linearization. The theoretical bases of the sliding mode variable structure control were introduced, and the stability proof was presented. Switching function of the system has been deduced, sliding mode voltage controller model has been established, and the output of the outer voltage loop is the instruction of the inner current loop. Affine nonlinear model of two input two output equations on d-q axis for current has been established its meeting conditions of exact linearization were proved. In order to improve the anti-jamming capability of the system, a variable structure control was added in the current controller, the control law was deduced. The dual-loop control with sliding mode control in outer voltage loop and linearization variable structure control in inner current loop was proposed. Simulation results demonstrate the effectiveness of the proposed control strategy even during the dc reference voltage and system load variation.
An Improved Power Quality BIBRED Converter-Based VSI-Fed BLDC Motor Drive
Singh, Bhim; Bist, Vashist
2014-01-01
This paper presents an IHQRR (integrated high-quality rectifier regulator) BIBRED (boost integrated buck rectifier energy storage DC-DC) converter-based VSI (voltage source inverter)-fed BLDC (brushless DC) motor drive. The speed control of BLDC motor is achieved by controlling the DC link voltage of the VSI using a single voltage sensor. This allows VSI to operate in fundamental frequency switching mode for electronic commutation of BLDC motor which reduces the switching losses due to high-frequency switching used in conventional approach of PWM (pulse width modulation)-based VSI-fed BLDC motor drive. A BIBRED converter is operated in a dual-DCM (discontinuous conduction mode) thus using a voltage follower approach for PFC (power factor correction) and DC link voltage control. The performance of the proposed drive is evaluated for improved power quality over a wide range of speed control and supply voltage variation for demonstrating the behavior of proposed drive. The power quality indices thus obtained are within the recommended limits by international PQ (power quality) standards such as IEC 61000-3-2.
Institute of Scientific and Technical Information of China (English)
林珍君; 黄声华; 万山明
2016-01-01
In order to decrease the carbon emissions and reduce the fuel cost of large-scale marine, the ideal way is to minimize the operational time of diesel generation system, and ship shaft synchronous generator converter is the best solution. The traditional ship shaft synchronous generator converter can''t make the full use of generator capacity, and has some deficiency of lower power factor, poor current THD, large fluctuations of DC link voltage, which leads to instability of invertor output voltage. This paper proposed a novel model combining the broad-frequency brushless excite synchronous generator (BFBESG) with the four-quadrant converter (FQC). On the generator side, a variable frequency PWM rectifier scheme had been proposed, including an inner current loop based on complex vector PI controller and an outer voltage loop based on balance of the instantaneous power.The resonant phase locked loop was adopted to lock the phase of generator terminal voltage. The 100kW experimental prototype of shaft synchronous generator converter had been developed. Through the prototype load experiment, the feasibility and superiority of the proposed control scheme are verified.%为了降低大型船舶航行时的碳排量和燃油成本,缩短柴油发电系统的运行时间成为一种理想的解决方案,而采用轴带发电系统则能较好地实现这一目标.传统轴带同步发电机变流器系统无法充分利用发电机容量,发电机侧功率因数较低且电流谐波含量高,直流母线电压波动较大,导致逆变侧输出的交流电压幅值不稳定.该文采用一种新型的宽频无刷励磁同步发电机(broad-frequency brushless excite synchronous generator,BFBESG)与四象限变流器(four- quadrant converter,FQC)相结合的方式.在轴带发电机侧,提出基于复矢量PI控制器电流内环和基于瞬时功率平衡的电压平方外环的双闭环变频PWM整流控制策略.采用变频谐振锁相环对发电机
High-power converters and AC drives
Wu, Bin
2017-01-01
This new edition reflects the recent technological advancements in the MV drive industry, such as advanced multilevel converters and drive configurations. It includes three new chapters, Control of Synchronous Motor Drives, Transformerless MV Drives, and Matrix Converter Fed Drives. In addition, there are extensively revised chapters on Multilevel Voltage Source Inverters and Voltage Source Inverter-Fed Drives. This book includes a systematic analysis on a variety of high-power multilevel converters, illustrates important concepts with simulations and experiments, introduces various megawatt drives produced by world leading drive manufacturers, and addresses practical problems and their mitigations methods.
Institute of Scientific and Technical Information of China (English)
吕永灿; 林桦; 杨化承; 罗咏
2013-01-01
To track the given sinusoidal current under stationary frame and suppress the effect of the low harmonics in the grid, a multi-resonant proportional resonant (PR) controller was adopted for pulse width modulation (PWM) converter with LCL filter based on capacitor current feedback active damping. Because the system is of high order, many parameters and complicated, the effects of the control parameters on the current-loop performance were investigated with frequency theory, i.e. the stability, steady-state error and phase margin. Based on this, a decoupling-simplified analytic design method was proposed. According to the requests of the stability, steady-state error and phase margin, the capacitor-current-feedback coefficient, the relative resonant gain factor and the proportional factor could be designed separately. The proposed method uses the analytic method and simplifies the couple of the parameters without trial-and-error procedure. Finally, a battery storage power conversion system (PCS) was built. Experiment results verify the effectiveness of the proposed design method.%基于电容电流反馈有源阻尼的LCL型脉宽调制(pulse width modulation，PWM)变换器并网电流控制中，通常采用多谐振比例谐振(proportional resonant，PR)控制器来实现静止αβ坐标系下正弦电流给定的无静差跟踪和抑制电网电压特定次谐波影响。针对电流环控制器复杂、参数多、设计难的问题，采用频率域理论分析电容电流反馈系数和准PR控制器各参数对电流环性能的影响。在此基础上，提出一种电流环控制器参数解耦简化解析设计方法，根据稳定性、稳态误差和相位裕度要求，分别设计电容电流反馈系数及PR控制器相对谐振增益系数和比例系数。该设计方法简化了控制器参数之间的耦合关系，且多采用解析计算，不需要反复试凑。实验结果验证了所提出的参数解耦解析设计方法是可行和有效的。
Assessment of the impact that individual voltage source has on a generator’s stability
DEFF Research Database (Denmark)
Dmitrova, Evgeniya; Jóhannsson, Hjörtur; Nielsen, Arne Hejde
2012-01-01
This paper presents an approach for splitting equivalent Thevenin voltage into components induced by each voltage source in the reduced grid. Thevenin equivalent representation of the system is sometimes used for stability assessment of a given generator, where the Thevenin voltage is one...... of the key variables affecting the stability conditions. Thevenin voltage is formed by components induced by each voltage source in the grid, while depending on topology and system parameters, the impact of these components on the equivalent Thevenin voltage Eth might vary considerably. This paper...
Scalar Controlled Boost PWM Rectifier for Micro Wind Energy Systems
Directory of Open Access Journals (Sweden)
J. Chelladurai
2015-05-01
Full Text Available Uses of Permanent Magnet Synchronous Generators (PMSG are increasing in variable speed micro-Wind Energy Conversion Systems (WECS. In stand-alone or grid-connected Micro-WECS, extraction of maximum power is vital. To extract maximum power output and to obtain a constant DC bus voltage from variable magnitude and variable frequency voltage output of PMSG and generally a two stage scheme namely i conventional diode bridge rectifier and ii DC-DC Boost/Buck/Buck-Boost converters are used. In this study, a single stage Scalar Controlled PWM (SCPWM Boost Rectifier is proposed in order to minimize the current harmonics and to improve the power factor on source side. The modeling and simulation of PMSG based wind generator and SCPWM Boost rectifier was developed in MATLAB. The harmonic content in the input current waveform of the proposed SCPWM rectifier is compared with the conventional three-phase bridge rectifier. The Simulation results show the effectiveness of the PWM Boost rectifier in terms of effective utilization of source, improved efficiency and harmonic mitigation for PMSG based Wind Generator. Simulation results demonstrate the effectiveness of the proposed system in reducing the current and voltage THD on source side.
DEFF Research Database (Denmark)
Federico, de Bosio; Pastorelli, Michele; Antonio DeSouza Ribeiro, Luiz
2016-01-01
State feedback coupling between the capacitor voltage and inductor current deteriorates notably the performance during transients of voltage and current regulators in stand-alone systems based on voltage source inverters. A decoupling technique is proposed, considering the limitations introduced ...... by system delays. Laboratory experiments were executed in compliance with the normative for Uninterruptible Power Supply systems to prove the developed analysis....
Two phase interleaved buck converter for driving high power LEDs
DEFF Research Database (Denmark)
Beczkowski, Szymon; Munk-Nielsen, Stig
2011-01-01
increases luminous efficacy of LED compared to PWM dimmed system. Because of the low dynamic resistance of LEDs the duty cycle of the converter does not change greatly with controlled current. By setting the input voltage of the buck converter to around twice the voltage of diode strings, converter can...
PWM Switching Strategy for Torque Ripple Minimization in BLDC Motor
Salah, Wael A.; Ishak, Dahaman; Hammadi, Khaleel J.
2011-05-01
This paper describes a new PWM switching strategy to minimize the torque ripples in BLDC motor which is based on sensored rotor position control. The scheme has been implemented using a PIC microcontroller to generate a modified Pulse Width Modulation (PWM) signals for driving power inverter bridge. The modified PWM signals are successfully applied to the next up-coming phase current such that its current rise is slightly delayed during the commutation instant. Experimental results show that the current waveforms of the modified PWM are smoother than that in conventional PWM technique. Hence, the output torque exhibits lower ripple contents.
Discrete/PWM Ballast-Resistor Controller
King, Roger J.
1994-01-01
Circuit offers low switching loss and automatic compensation for failure of ballast resistor. Discrete/PWM ballast-resistor controller improved shunt voltage-regulator circuit designed to supply power from high-resistance source to low-impedance bus. Provides both coarse discrete voltage levels (by switching of ballast resistors) and continuous fine control of voltage via pulse-width modulation.
Regeneration of ZVS converter with Resonant inductor
Directory of Open Access Journals (Sweden)
J.Sivavara Prasad
2011-09-01
Full Text Available This paper presents an analysis of the regeneration of zero-voltage-switching converter with resonant inductor, quasi-resonant converters, and full-bridge zero-voltage-switched PWM Converter. The design of a clamping circuit considering a saturable resonant inductor is presented and compared with the design of a clamping circuit with a linear resonant inductor. A diode model with reverse recovery is employed to simulate the effects.
Brainard, John P.; Christenson, Todd R.
2009-11-03
A charge-pump voltage converter for converting a low voltage provided by a low-voltage source to a higher voltage. Charge is inductively generated on a transfer rotor electrode during its transit past an inductor stator electrode and subsequently transferred by the rotating rotor to a collector stator electrode for storage or use. Repetition of the charge transfer process leads to a build-up of voltage on a charge-receiving device. Connection of multiple charge-pump voltage converters in series can generate higher voltages, and connection of multiple charge-pump voltage converters in parallel can generate higher currents. Microelectromechanical (MEMS) embodiments of this invention provide a small and compact high-voltage (several hundred V) voltage source starting with a few-V initial voltage source. The microscale size of many embodiments of this invention make it ideally suited for MEMS- and other micro-applications where integration of the voltage or charge source in a small package is highly desirable.
FPGA Techniques Based New Hybrid Modulation Strategies for Voltage Source Inverters
Sudha, L. U.; J. Baskaran; Elankurisil, S. A.
2015-01-01
This paper corroborates three different hybrid modulation strategies suitable for single-phase voltage source inverter. The proposed method is formulated using fundamental switching and carrier based pulse width modulation methods. The main tale of this proposed method is to optimize a specific performance criterion, such as minimization of the total harmonic distortion (THD), lower order harmonics, switching losses, and heat losses. The proposed method is articulated using fundamental switch...
DEFF Research Database (Denmark)
Qin, Zian; Loh, Poh Chiang; Blaabjerg, Frede
2015-01-01
. With the SVPWM or DPWM proposed in literatures, the generation of the references is phase voltage based. But the phase voltages actually cannot be controlled directly by the PWM converter, since they can be influenced by both of terminal voltages and the load network while the PWM converter can only control...
Variable speed wind turbine generator system with current controlled voltage source inverter
Energy Technology Data Exchange (ETDEWEB)
Muyeen, S.M., E-mail: muyeen0809@yahoo.co [Dept. of Electrical Engineering, Petroleum Institute, P.O. Box 2533, Abu Dhabi (United Arab Emirates); Al-Durra, Ahmed [Dept. of Electrical Engineering, The Petroleum Institute, P.O. Box 2533, Abu Dhabi (United Arab Emirates); Tamura, J. [Dept. of EEE, Kitami Institute of Technology, 165 Koen-cho, Kitami 090-8507 (Japan)
2011-07-15
highlights: {yields} Current controlled voltage source inverter scheme for wind power application. {yields} Low voltage ride through of wind farm. {yields} Variable speed wind turbine driven permanent magnet synchronous generator-operation and control. -- Abstract: The present popular trend of wind power generation is to use variable speed wind turbine (VSWT) driving a doubly fed induction generator (DFIG), wound field synchronous generator (WFSG) or permanent magnet synchronous generator (PMSG). Among them, stability analyses of DFIG type of VSWT have already been reported in many literatures. However, transient stability and low voltage ride through (LVRT) characteristics analyses for synchronous generator type of VSWT is not sufficient enough. This paper focuses on detailed LVRT characteristic analysis of variable speed wind turbine driving a PMSG (VSWT-PMSG) with current controlled voltage source inverter (CC-VSI). Modeling and suitable control strategies for overall system are developed to augment the low voltage ride through capability of variable speed wind generator, considering recent wind farm grid code. Both symmetrical and unsymmetrical faults are analyzed as network disturbances in this paper. The permanent fault due to unsuccessful reclosing of circuit breakers is taken into consideration, which is a salient feature of this study. Moreover, the dynamic characteristic is analyzed using real wind speed data measured in Hokkaido Island, Japan. The proposed control scheme is simulated by using the standard power system simulation package PSCAD/EMTDC and results are verified by comparing that of voltage controlled voltage source inverter scheme available in power system literature.
Fundamental Approach in Digital Circuit Design for 1-MHz Frequency PWM Gate Drive Application
Directory of Open Access Journals (Sweden)
Nor Zaihar Yahaya
2011-01-01
Full Text Available This paper discusses the design of a digital programmable logic circuit to produce a 5 V - output square wave pulses for four high power MOSFET switches using a fixed PWM circuit. It will be applied to drive the synchronous rectifier buck converter(SRBC circuit. The PWM signals with multiple fixed time delay of 15 ns, 232 ns, 284 ns and 955 ns are generated. The steps taken to analyze each propagation time delay of each logic gate used and its combination are carefully studied. A multiplexer is added at the output of the logic circuit to select and produce the desired output pulses of 20% duty ratio. The logic outputs are compared with the analog pulses and results match each other within 1% in difference.
Directory of Open Access Journals (Sweden)
Rathnakannan Kailasam
2008-01-01
Full Text Available This paper describes the modelling and the analysis of control logic for a Nano-Device- based PWM controller. A comprehensive simple SPICE schematic model for Single Electron transistor has been proposed. The operation of basic Single Electron Transistor logic gates and SET flip flops were successfully designed and their performances analyzed. The proposed design for realizing the logic gates and flip-flops is used in constructing the PWM controller utilized for switching the buck converter circuit. The output of the converter circuit is compared with reference voltage, and when the error voltage and the reference are matched the latch is reset so as to generate the PWM signal. Due to the simplicity and accuracy of the compact model, the simulation time and speed are much faster, which makes it potentially applicable in large-scale circuit simulation. This study confirms that the SET-based PWM controller is small in size, consumes ultra low power and operates at high speeds without compromising any performance. In addition these devices are capable of measuring charges of extremely high sensitivity.
Directory of Open Access Journals (Sweden)
Ajay Kumar Maurya, Kishore Chahar, Y. K. Chauhan
2013-03-01
Full Text Available This paper presents the analysis of a photovoltaicbases three-phase five level voltage source inverter(VSI supplying induction motor driven waterpump. The VSI uses a unipolar PWM technique forproducing three phase 5 level voltage output andthis output is used to drive three-phase inductionmotor driving a pump load. Multilevel inverters areused for generating AC voltage from several levelsof DC voltages and enhance the performance of thesystem. The proposed system is used to reduce thefiltering requirements and reduce the amplitude ofall harmonics at the output of the inverter. ThePower quality improves by reducing the harmonicslevel. The complete simulation model is simulatedin MATLAB/SIMULINK and validates thetheoretical considerations
2014-01-01
In order to utilize the energy from the renewable energy sources, power conversion system is necessary, in which the voltage source inverter (VSI) is usually the last stage for injecting power to the grid. It is an economical solution to add the function of power quality conditioning to the grid-connected VSI in the low-voltage distribution system. Two multifunctional VSIs are studied in this paper, that is, inductive-coupling VSI and capacitive-coupling VSI, which are named after the fundame...
Stability analysis and design of the improved droop controller on a voltage source inverter
DEFF Research Database (Denmark)
Calabria, Mauro; Schumacher, Walter; Guerrero, Josep M.;
2015-01-01
This paper studies the dynamics of a droop-controlled voltage source inverter connected to a stiff grid and addresses the use of the improved droop controller in order to enhance the dynamic behavior of the system. The small-signal stability of the inverter is studied in depth considering...... variations on its droop parameters, providing a general understanding on the functioning of such system. Finally, three methods to tune the dynamic droop gain are introduced and compared, providing analytical, simulation, and experimental results....
Directory of Open Access Journals (Sweden)
Javad Faiz
2011-01-01
Full Text Available A UPS inverter operates in wide load impedance ranges from resistive to capacitive or inductive load. At the same time, fast transient load response, good load regulation and good switching frequency suppression is required. The variation of the load impedance changes the filter transfer characteristic and thus the output voltage value. In this paper, an analysis and simulation of the single phase voltage source uninterruptible power supply (UPS with fourth order filter (multiple-filter in output inverter, based on the state space averaging and small signal linearization technique, is proposed. The simulation results show the high quality sinusoidal output voltage at different loads, with THD less than %5.
DEFF Research Database (Denmark)
Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang
2014-01-01
the grid-side inductor, and the use of a high-pass filter with a negative sign shapes the virtual impedance by an RL damper paralleled by a negative inductance. It is further found that such a negative virtual inductance plays a critical role in mitigating the phase lag caused by the time delay...... in a digital control system. The instability induced by the negative virtual resistance, which is commonly experienced in the feedback-type active damping, can thus be avoided. A systematic design method of the highpass filter is also proposed by the help of root locus analysis in the discrete z-domain. Lastly...
Phase-lock loop of Grid-connected Voltage Source Converter under non-ideal grid condition
DEFF Research Database (Denmark)
Wang, Haojie; Sun, Hai; Han, Minxiao
2015-01-01
phase information cannot be accurately tracked. Based on analysis of the cause of double-frequency ripple when unbalance exists in main grid, a phase-locked loop (PLL) detection technique is proposed. Under the conditions of unsymmetrical system voltage, varying system frequency, single-phase system...... and distorted system voltage the proposed PLL can accurately detect the fundamental positive-sequence component of grid voltage thus accurate control of DC micro-grid voltage can be realized....
Switching power converters medium and high power
Neacsu, Dorin O
2013-01-01
An examination of all of the multidisciplinary aspects of medium- and high-power converter systems, including basic power electronics, digital control and hardware, sensors, analog preprocessing of signals, protection devices and fault management, and pulse-width-modulation (PWM) algorithms, Switching Power Converters: Medium and High Power, Second Edition discusses the actual use of industrial technology and its related subassemblies and components, covering facets of implementation otherwise overlooked by theoretical textbooks. The updated Second Edition contains many new figures, as well as
PWM模拟DAC的关键参数分析%Key parameters analysis of DAC using PWM
Institute of Scientific and Technical Information of China (English)
赵月丽
2014-01-01
PWM 模拟 DAC 技术由于其价格便宜、技术简单在低成本嵌入式系统中应用广泛，然而其性能指标却无法与集成的 DAC 相比。建模讨论了影响 PWM 模拟实现 DAC 系统的性能的主要因素。仿真发现，滤波器环节对于 PWM 模拟 DAC 的性能参数是至关重要的，在不考虑 PWM 的位数限制时，滤波级数越高 DAC 精度越高，然而 DAC 的建立时间也会显著增加。分析发现，这两个主要参数分别取决于滤波系统对于高频成分的频率响应和对于直流分量的阶跃响应。具体应用中应该权衡DAC 精度和转换速度，以确保应用 PWM 模拟 DAC 可以满足具体应用需求。%DAC (Digital-to-Analog Converter) using PWM (Pulse Width Modulation) technology is widely used in low cost embedded systems due to cheap price and simple to use, however its performance index cannot match the real DAC. In this paper, models are built to discuss the main factors which affect the performance of PWM imitated DAC system. Through simulation it finds that the filter plays a key role in the DAC, without considering the digits limit of PWM, the higher the filter series the more accurate the DAC is, however, the establishment time of the DAC will increase significantly. Through analysis it finds that the two main parameters depend on the high frequency response and DC step response of the filtering system respectively. In specific applications, the precision and transformation speed of the DAC should be carefully weighed to meet specific requirements.
应用于V2G的AC/DC矩阵变换器%AC/DC Matrix Converters for V2G Applications
Institute of Scientific and Technical Information of China (English)
王辉; 粟梅; 孙尧; 李幸; 韩华; 张关关
2013-01-01
Due to the problems of battery voltage adaptation and power-volume ratio and system efficiency of the pulse width modulation (PWM) voltage source rectifier (VSR)in vehicle to grid (V2G) systems,this paper presents a solution based on AC/DC matrix converter topology for the V2G Against the characteristic of relatively large charging current ripple in the classical current space vector modulation strategy,a sectional optimized modulation strategy that can reduce the charging current ripple within the whole output range was proposed.The comparative analysis was made between the classical current space vector modulation strategy and the proposed strategy.The simulation and experimental results demonstrate the validity and effectiveness of the proposed sectional optimized modulation strategy.%由于当前V2G系统中普遍采用的电压型脉宽调制(pulse width modulation,PWM)整流方案中所存在的蓄电池电压匹配、功率体积比及系统效率问题,提出一种采用AC/DC矩阵变换器的解决方案.针对经典电流空间矢量调制策略中充电电流纹波较大的缺点,提出一种在全输出范围内减小充电电流纹波的分段优化调制策略,并深入对比分析这两种调制策略下充电电流纹波的大小.仿真和实验结果表明,所提分段优化调制策略的正确性和可行性.
DEFF Research Database (Denmark)
Behrouzian, Ehsan; Bongiorno, Massimo; Teodorescu, Remus
2014-01-01
The purpose of this paper is to investigate the impact of switching harmonics on the instantaneous power that flows in the cells of a chain-link based STATCOM when using Phase-Shifted PWM. Two different cases are investigated for the converter cells: low, and high switching frequency. It is shown...... distribution among cells of the same phase leg, thus contributing to the capacitors balancing. Theoretical conclusions are validated through PSCAD simulation results....
Comparison of Performance of VSI and Z-Source Inverter for Space Vector PWM
Directory of Open Access Journals (Sweden)
E. Sai Prateek
2014-05-01
Full Text Available Z-Source Inverters have the ability to boost the dc link voltage, thus increasing the output ac voltage beyond the values reached by conventional inverters. The enhanced ratio from ac output voltage to dc link voltage is possible due to an impedance network connected between the dc power supply and the main converter. The space vector pulse width modulation techniques gives more dc bus utilisation and low harmonics than other pulse width modulation techniques. In this paper space vector pwm is implemented for conventional VSI and Zsource inverter. The results are supported by SIMULINK simulation
A New Hard Switching Bidirectional Converter With High Power Density
Directory of Open Access Journals (Sweden)
Bahador Fani
2010-01-01
Full Text Available In this paper, a new isolated dc-dc bidirectional converter is proposed. This converter consists of two transformers (flyback and forward and only one switch in primary side and one switch in secondary side of transformers. In this converter energy transfers to the output in both on and off switch states so power density of this converter is high This converter controlled by PWM signal. Also this converter operates over a wide input voltage range. Theoretical analysis is presented and computer simulation and experimental results verify the converter analysis.
FPGA techniques based new hybrid modulation strategies for voltage source inverters.
Sudha, L U; Baskaran, J; Elankurisil, S A
2015-01-01
This paper corroborates three different hybrid modulation strategies suitable for single-phase voltage source inverter. The proposed method is formulated using fundamental switching and carrier based pulse width modulation methods. The main tale of this proposed method is to optimize a specific performance criterion, such as minimization of the total harmonic distortion (THD), lower order harmonics, switching losses, and heat losses. The proposed method is articulated using fundamental switching and carrier based pulse width modulation methods. Thus, the harmonic pollution in the power system will be reduced and the power quality will be augmented with better harmonic profile for a target fundamental output voltage. The proposed modulation strategies are simulated in MATLAB r2010a and implemented in a Xilinx spartan 3E-500 FG 320 FPGA processor. The feasibility of these modulation strategies is authenticated through simulation and experimental results.
Institute of Scientific and Technical Information of China (English)
Juming CHEN; Feng LIU; Shengwei MEI
2006-01-01
Active power filter (APF) based on voltage source inverter (VSI) is one of the important measures for handling the power quality problem. Mathematically, the APF model in a power grid is a typical nonlinear one. The idea of passivity is a powerful tool to study the stabilization of such a nonlinear system. In this paper, a state-space model of the four-leg APF is derived, based on which a new H-infinity controller for current tracking is proposed from the passivity point of view. It can achieve not only asymptotic tracking, but also disturbance attenuation in the sense of L2-gain. Subsequently,a sufficient condition to guarantee the boundedness and desired mean of the DC voltage is also given. This straightforward condition is consistent with the power-balancing law of electrical circuits. Simulations performed on PSCAD platform verify the validity of the new approach.
A low-power circuit for piezoelectric vibration control by synchronized switching on voltage sources
Shen, Hui; Ji, Hongli; Zhu, Kongjun; Balsi, Marco; Giorgio, Ivan; dell'Isola, Francesco
2010-01-01
In the paper, a vibration damping system powered by harvested energy with implementation of the so-called SSDV (synchronized switch damping on voltage source) technique is designed and investigated. In the semi-passive approach, the piezoelectric element is intermittently switched from open-circuit to specific impedance synchronously with the structural vibration. Due to this switching procedure, a phase difference appears between the strain induced by vibration and the resulting voltage, thus creating energy dissipation. By supplying the energy collected from the piezoelectric materials to the switching circuit, a new low-power device using the SSDV technique is proposed. Compared with the original self-powered SSDI (synchronized switch damping on inductor), such a device can significantly improve its performance of vibration control. Its effectiveness in the single-mode resonant damping of a composite beam is validated by the experimental results.
Self-oscillating resonant power converter
DEFF Research Database (Denmark)
2014-01-01
The present invention relates to resonant power converters and inverters comprising a self-oscillating feedback loop coupled from a switch output to a control input of a switching network comprising one or more semiconductor switches. The self-oscillating feedback loop sets a switching frequency...... of the power converter and comprises a first intrinsic switch capacitance coupled between a switch output and a control input of the switching network and a first inductor. The first inductor is coupled in-between a first bias voltage source and the control input of the switching network and has...... a substantially fixed inductance. The first bias voltage source is configured to generate an adjustable bias voltage applied to the first inductor. The output voltage of the power converter is controlled in a flexible and rapid manner by controlling the adjustable bias voltage....
Directory of Open Access Journals (Sweden)
BOTEZAN, A.
2015-08-01
Full Text Available The paper presents the hysteresis current control of the voltage source inverter. The eMEGAsim real-time simulator is developed by OPAL-RT. Real-time simulation is used in many cases because it allows the behavior of the industrial processes operation to be determined. Two research directions are developed in this case, Rapid Control Prototyping and Hardware-In-the-Loop. Using eMEGAsim simulator allows implementing the command and control strategy of a single-phase voltage source inverter. At this stage, the real-time behavior of operation is monitored, because the voltage source inverter will be the part of a single-phase shunt active filter. In order to command and control the voltage source inverter, the current and voltage signals are acquired, since these signals are necessary to estimate reference signal. Extension of the Instantaneous Reactive Power Theorem is used because this theorem is suitable for single-phase active filter control. To test the real-time command and control strategy implemented, it was used a low power single-phase voltage source inverter (full bridge.
High frequent modelling of a modular multilevel converter using passive components
DEFF Research Database (Denmark)
El-Khatib, Walid Ziad; Holbøll, Joachim; Rasmussen, Tonny Wederberg
2013-01-01
Prevalence of High Voltage direct current (HVDC) based on Voltage source converters (VSC) has made it necessary to investigate the behavior of the converter under various fault conditions. In this paper we will deal with the transient characteristics of a modular multilevel converter (MMC). This ...
Analysis of Input and Output Ripples of PWM AC Choppers
Directory of Open Access Journals (Sweden)
Pekik Argo Dahono
2008-11-01
Full Text Available This paper presents an analysis of input and output ripples of PWM AC choppers. Expressions of input and output current and voltage ripples of single-phase PWM AC choppers are first derived. The derived expressions are then extended to three-phase PWM AC choppers. As input current and output voltage ripples specification alone cannot be used to determine the unique values of inductance and capacitance of the LC filters, an additional criterion based on the minimum reactive power is proposed. Experimental results are included in this paper to show the validity of the proposed analysis method.
Three-Phase Back PWM-PFC Rectifier
Institute of Scientific and Technical Information of China (English)
Yasuyuki Nishida
2005-01-01
A new 3-phase back (or current-source-type) PWM-PFC rectifier is proposed in this paper. The necessity,the advantages and disadvantages of this type PWM rectifier are discussed first.Then,the new power circuit topology and the modulation scheme to eliminate or mitigate the disadvantages and obtain further new advantages of the buck PWM rectifier are introduced.The features of the new rectifier, i.e., high efficiency, simple modulation process, robustness of the line-current modulation for distortion of the utility voltages and DC current ripples have been confirmed through experimental results obtained from a 12kW prototype.
Design of a PWM Speed - governing System for DC Motor Based on PLC%基于PLC的直流电机PWM调速系统设计
Institute of Scientific and Technical Information of China (English)
何新霞; 邢瑞军
2011-01-01
设计了基于SIMATIC S7-200 PLC直流电机PWM调速系统.主电路采用双极式可逆PWM变换器,选用集成驱动器M57962L,通过设计其驱动外围电路,实现了对IGBT的导通和关断控制.采用硬件延时电路,防止上、下桥臂直通事故的发生.利用PLC的高速计数功能实现了对电机转速的测量,设计开发了基于PLC的PI控制程序及PWM信号产生程序.从而实现了直流电机的PWM调速,并实现了转速的无静差调节.%The paper presents the design of PWM speed - governing system for DC motor based on S7 - 200 - PLC. The double - polar reversible PWM converter is used and integrated drive electronics M57962 is selected in main circuit. The conduction and switch control of IGBT is realized by designing the peripheral driving circuitry. The delayed circuit is adopted to prevent the shoot -through phenomenon between upper and lower bridge arm in a PWM. Programs for PLC PI control and for PWM signal generation are developed to implement PWM speed- governing for DC motor and floating control on speed.
基于PSIM的PWM逆变器通用仿真模型%The General Simulation Model of PWM Inverter on PSIM
Institute of Scientific and Technical Information of China (English)
赵春柳
2013-01-01
PWM（Pusle Width Modulation，PWM）逆变器的应用越来越广泛，而PWM逆变器的控制模式又多种多样，因此对于系统仿真而言，建立PWM逆变器的通用仿真模型就尤为重要。该文建立三相全桥PWM逆变器的仿真模型，通过仿真表明该模型具有结构简单、通用性好和仿真效率高的特点。%Application of PWM(Pusle Width Modulation,PWM)inverter is more and more extensive, and there are all kinds of control method of PWM inverter, so the establishment of general simulation model of PWM inverter is very important when sys?tem simulation is needed. A simualtion model of three-phase full bridge PWM converter is established in this paper, it is proved that the configuration of simulation model is simple, the generality of this model is good and the simulation efficiency is high.
Directory of Open Access Journals (Sweden)
Ibekwe B.E
2014-10-01
Full Text Available The ac to dc converters’ power factors correction in ac transmission system were investigated. The studies include: phase-controlled converter; pulse width modulated (PWM converter and ac input current shaped converter. Using Fourier series, power factors of these converters were calculated and simulated using MATLAB. The resulting curves are displayed in the hard copies for practical guides in the choice of converters; and comparatively, current shaped type is the best.
Soft switching bidirectional DC-DC converter for ultracapacitor-batteries interface
Energy Technology Data Exchange (ETDEWEB)
Adib, Ehsan; Farzanehfard, Hosein [Dept. of Electrical and Computer Engineering, Isfahan Univ. of Technology (Iran)
2009-12-15
In this paper a new soft switching bidirectional DC-DC converter is introduced which can be applied as the interface circuit between ultracapacitors and batteries or fuel cells. All semiconductor devices in the proposed converter are soft switched while the control circuit remains PWM. Due to achieved soft switching condition, the energy conversion through the proposed converter is highly efficient. The proposed converter is analyzed and a prototype converter is implemented. The presented experimental results confirm the theoretical analysis. (author)
Selective harmonic control for power converters
DEFF Research Database (Denmark)
Zhou, Keliang; Yang, Yongheng; Blaabjerg, Frede;
2014-01-01
This paper proposes an Internal Model Principle (IMP) based Selective Harmonic Controller (SHC) for power converters. The proposed SHC offers an optimal control solution for power converters to mitigate power harmonics. It makes a good trade-off among cost, complexity and performance. It has high...... accuracy and fast transient response, and it is cost-effective, easy for real-time implementation, and compatible for design rules-of-thumb. An application on a three-phase PWM converter has confirmed the effectiveness of the proposed control scheme in terms of harmonic mitigation....
Directory of Open Access Journals (Sweden)
NingYi Dai
2014-01-01
Full Text Available In order to utilize the energy from the renewable energy sources, power conversion system is necessary, in which the voltage source inverter (VSI is usually the last stage for injecting power to the grid. It is an economical solution to add the function of power quality conditioning to the grid-connected VSI in the low-voltage distribution system. Two multifunctional VSIs are studied in this paper, that is, inductive-coupling VSI and capacitive-coupling VSI, which are named after the fundamental frequency impedance of their coupling branch. The operation voltages of the two VSIs are compared when they are used for renewable energy integration and power quality conditioning simultaneously. The operation voltage of the capacitive-coupling VSI can be set much lower than that of the inductive-coupling VSI when reactive power is for compensating inductive loads. Since a large portion of the loads in the distribution system are inductive, the capacitive-coupling VSI is further studied. The design and control method of the multifunctional capacitive-coupling VSI are proposed in this paper. Simulation and experimental results are provided to show its validity.
Dai, NingYi; Lam, Chi-Seng; Zhang, WenChen
2014-01-01
In order to utilize the energy from the renewable energy sources, power conversion system is necessary, in which the voltage source inverter (VSI) is usually the last stage for injecting power to the grid. It is an economical solution to add the function of power quality conditioning to the grid-connected VSI in the low-voltage distribution system. Two multifunctional VSIs are studied in this paper, that is, inductive-coupling VSI and capacitive-coupling VSI, which are named after the fundamental frequency impedance of their coupling branch. The operation voltages of the two VSIs are compared when they are used for renewable energy integration and power quality conditioning simultaneously. The operation voltage of the capacitive-coupling VSI can be set much lower than that of the inductive-coupling VSI when reactive power is for compensating inductive loads. Since a large portion of the loads in the distribution system are inductive, the capacitive-coupling VSI is further studied. The design and control method of the multifunctional capacitive-coupling VSI are proposed in this paper. Simulation and experimental results are provided to show its validity.
Mitigation of Lower Order Harmonics with Filtered Svpwm In Multiphase Voltage Source Inverters
Directory of Open Access Journals (Sweden)
K. Uday Kiran
2014-08-01
Full Text Available Multi-phase machines and drives is a topic of growing relevance in recent years, and it presents many challenging issues that still need further research. This is the case of multi-phase space vector pulse width modulation (SVPWM, which shows not only more space vectors than the standard three-phase case, but also new subspaces where the space vectors are mapped. In the digital implementation, multiphase reference voltages are sampled and fed into the digital modulator to produce gating signals at a constant clock rate f. This means a finite pulse-width resolution because the gating state transition can only occur at some specific time instants depending on frequency. This results in a deviation of produced phase voltages from the desired phase voltages, i.e., increasing harmonic distortion especially for a small modulation index signal. In the present paper a filtered space-vector pulse-width modulation (SVPWM considering finite pulse-width resolution is proposed to produce a switching sequence with reduced baseband harmonics for multiphase voltage source inverters (VSI. This is achieved by incorporating a pseudo feedback loop regarding weighted voltage difference between desired and produced phase voltages.
Teruya, Daisuke; Masukawa, Shigeo; Iida, Shoji
We propose a novel inverter that can be operated either as a Current Source Inverter (CSI) or as a Voltage Source Inverter (VSI) by changing only the control signals. It is proper to apply it to the interconnecting system with renewal energy, such as photovoltaic cells or wind generation systems, to a grid. This inverter is usually operated as the CSI connected to the grid. Even if the energy source has a lower voltage than the grid, the energy can be supplied to the grid through the proposed inverter. The power factor can be briefly maintained at almost unity. When power supply from the grid is interrupted, the proposed circuit should be operated as the VSI in the stand-alone operation mode. In this way, the circuit can maintain a constant output voltage to the loads. In this paper, the proposed circuit configuration and the control schemes for both the CSI and the VSI are described. Further, the circuit characteristics for both are discussed experimentally.
DEFF Research Database (Denmark)
Wang, Xiongfei; Blaabjerg, Frede; Chen, Zhe
2012-01-01
The virtual output impedance loop is known as an effective way to enhance the load sharing stability and quality of droop-controlled parallel inverters. This paper proposes an improved design of virtual output impedance loop for parallel three-phase voltage source inverters. In the approach, a vi...
Analysis of a novel phase-shifted soft switch converter
Institute of Scientific and Technical Information of China (English)
蒋志宏; 黄立培; 张义
2002-01-01
In this paper, on the basis of the phase-shifted controlled zero-voltage-switch (ZVS) full-bridge converter with pulse width modulation (PWM), a novel zero-voltage and zero-current switch (ZVZCS) PWM converter using a simple auxiliary circuit was designed. The ZVZCS soft switch is achieved by the resonance among the resisting electromagnetic deflection capacitor, the capacitor of the simple auxiliary network and the leakage inductor of transformer. There are no dissipation devices of the saturation inductor and the auxiliary switch in the converter, meantime the capacitor of the auxiliary circuit is also used to clamp the voltage of the rectifier, and there is no additional clamped circuit. There is no big circulating current in the converter, all the active and passive devices work on the condition of the low current and voltage stress, and the proposed converter has wide load range and small duty loss.
A Fuzzy-Logic-Based Controller for Three-Phase PWM Rectifier With Unity Power Factor Operation
Directory of Open Access Journals (Sweden)
A. Bouafia
2008-03-01
Full Text Available In this paper, direct power control (DPC of three-phase PWM rectifiers based on fuzzy logic controller is presented, without line voltage sensors. The control technique is built upon the ideas of the well known direct torque control (DTC for induction motors. The instantaneous active and reactive powers, directly controlled by selecting the optimum state of the converter, are used as the PWM control variables instead of the phase line currents being used. The proposed fuzzy logic controller presents the advantage to be based on linguistic description and does not require a mathematical model of the system. The controller ensures a good regulation of the output voltage, and guarantees the power factor close to one. The simulation results show that the designed fuzzy controller has a good dynamic behavior, a good rejection of impact load disturbance, and is very robust.
Maetani, Tatsuo; Isomura, Yoshinori; Watanabe, Akihiko; Iimori, Kenichi; Morimoto, Shigeo
This paper describes an ungrounded common-mode equivalent circuit for a motor driven by a voltage-source PWM inverter. When the capacitance of the rotor was is small, the reversal of the polarities of the common-mode voltage and shaft voltage is observed. In order to model this reversal, a bridge-type equivalent circuit is proposed. On the basis of calculations and experiment, it is found the values and polarity of the shaft voltage can be are accurately determined with the proposed equivalent circuit. Furthermore, the capacitance value of the insulated rotor required to make the shaft voltage equal to or less than the dielectric breakdown voltage of the bearing grease is obtained.
AC Motor Drive Fed by Renewable Energy Sources with PWM
Directory of Open Access Journals (Sweden)
J. Pavalam
2014-01-01
Full Text Available In this fast aproaching nature of technology the ned of Electricity becomes a mandatory in developing technology. The ned of Electricity increases the power demand where the power demand met by the conventional sources of energy has some disadvantage of polution, this disadvantage can be decreased by the use of the Renewable energy sources like Fuel Cel and available solar energy. When a FUEL cel produces AC power, basicaly two stages are required for conversion first a bosting stage and second is inversion stage. In this paper the Bost inverter topology is achieved where in the conventional methods the normal DC - AC power conversion method is used where as in this paper the PWM based DC - AC inverter has ben used which is useful in reducing the harmonics in the output of the Inverter. The voltage controled output is produced in the bost inverter the curent controled output is taken from dc-dc bidirectional converter. The Fuel cel canot be relied as a whole so a Solar PV module is conected acros the Load so while the Sunlight days the PV arays generate power and in the night time the Fuel cel is used to generate power for the load. Since, the Fuel cel and PV arays can generate power in Partial load they are prefered than any other sources. When the output from the Solar PV aray is low or when the sunlight available is not eficient in generating the power a automatic switch over is provided in the junction betwen the Solar PV aray and Fuel cel so that whenever it hapens the switch automaticaly switch over to another source. The simulation results are presented to confirm the operational feature of the proposed system.
Hysteretic Current Controlled Zvs Dc/Dc Converter For Automobile
DEFF Research Database (Denmark)
Cernat, M.; Scortarul, P.; Tanase, A.
2007-01-01
A novel bi-directional dc-dc converter with ZVS and interleaving for dual voltage systems in automobiles is presented. A variable frequency extended band hysteretic current control method is proposed. In comparison with classical fixed frequency current control PWM, the reverse polarity peak curr...
A Three-level 4 x 3 Conventinal Matrix Converter
DEFF Research Database (Denmark)
Rong, Runjie; Loh, Poh Chiang; Wang, Peter;
2007-01-01
This paper proposes a topology of a three-level 4 × 3 conventional matrix converter with 12 bi-directional switches. PWM control and modulation index compensation have been investigated. Operation theory has been verified by the simulation results using Matlab. The simulation results show that th...
Grid Filter Design for a Multi-Megawatt Medium-Voltage Voltage Source Inverter
DEFF Research Database (Denmark)
Rockhill, A.A.; Liserre, Marco; Teodorescu, Remus
2011-01-01
This paper describes the design procedure and performance of an LCL grid filter for a medium-voltage neutral point clamped (NPC) converter to be adopted for a multimegawatt wind turbine. The unique filter design challenges in this application are driven by a combination of the medium voltage......-megawatt filter connecting a medium-voltage converter switching at low frequency to the electric grid. This paper demonstrates a frequency domain model based approach to determine the optimum filter parameters that provide the necessary performance under all operating conditions given the necessary design...... converter, a limited allowable switching frequency, component physical size and weight concerns, and the stringent limits for allowable injected current harmonics. Traditional design procedures of grid filters for lower power and higher switching frequency converters are not valid for a multi...
Grid Filter Design for a Multi-Megawatt Medium-Voltage Voltage Source Inverter
DEFF Research Database (Denmark)
Rockhill, A.A.; Liserre, Marco; Teodorescu, Remus
2011-01-01
converter, a limited allowable switching frequency, component physical size and weight concerns, and the stringent limits for allowable injected current harmonics. Traditional design procedures of grid filters for lower power and higher switching frequency converters are not valid for a multi......This paper describes the design procedure and performance of an LCL grid filter for a medium-voltage neutral point clamped (NPC) converter to be adopted for a multimegawatt wind turbine. The unique filter design challenges in this application are driven by a combination of the medium voltage......-megawatt filter connecting a medium-voltage converter switching at low frequency to the electric grid. This paper demonstrates a frequency domain model based approach to determine the optimum filter parameters that provide the necessary performance under all operating conditions given the necessary design...
imulation Results of Single Stage AC- AC Converter for Induction Heating
Directory of Open Access Journals (Sweden)
S. ARUMUGAM
2010-12-01
Full Text Available This paper presents simulation of single stage Induction heating system with series Load Resonance. Low frequency AC is converted in to High Frequency Ac using newly developed ZVS-PWM high frequency inverter. This High Frequency is used for Induction Heating .Single stage AC-AC converter system is modeled and simulated using Matlab Simulink. The simulation results of ZVS-PWM high frequency system are presented. The effectiveness of this UFAC-to-HFAC direct power frequency converter using IGBTs for consumer high-frequency IH appliances is evaluated and proved on the basis of simulation results.
Medium voltage three-level converters for the grid connection of a multi-MW wind turbine
DEFF Research Database (Denmark)
Senturk, Osman Selcuk; Helle, Lars; Munk-Nielsen, Stig;
2009-01-01
Three-level (3L) neutral point clamped (NPC), flying capacitor (FC), and H-bridge (HB) voltage source converters (VSCs) as a grid-side full-scale medium voltage (MV) converter are modeled, controlled, and simulated for the grid connection of a hypothetical 6MW wind turbine. Via the converter topo...
Energy Technology Data Exchange (ETDEWEB)
Rodrigues, Kleiber David; Oliveira, Jose Carlos de; Penna, Cristiane [Universidade Federal de Uberlandia (UFU), MG (Brazil)
2001-10-15
This article aims at presenting the results of investigations made in laboratory involving frequency converters performance fed by voltage, PWM sinusoidal type, in relation to the electric energy quality. For that, it was used a commercial converter of the type VSI-PWM fed by a programmable source capable to reproduce disturbances related to the several variable items of energy quality for measurements of spectra of harmonics.
Simple Digital Control of a Two-Stage PFC Converter Using DSPIC30F Microprocessor
DEFF Research Database (Denmark)
Török, Lajos; Munk-Nielsen, Stig
2010-01-01
and built for 70W rated output power. Average current mode control for boost converter and current programmed control for forward converter are implemented on a dsPIC30F1010. Pulse Width Modulation (PWM) technique is used to drive the switching MOSFETs. Results show that digital solutions with ds...
Two-Phase Interleaved Buck Converter with a new Digital Self-Oscillating Modulkator
DEFF Research Database (Denmark)
Jakobsen, Lars Tønnes; Andersen, Michael Andreas E.
2007-01-01
for traditional digital PWM modulators given a certain switching frequency. A synchronised version of the DiSOM modulator is derived for interleaved converters. A prototype interleaved Buck converter for Point of Load applications has been designed and built to test the performance of DiSOM modulator. The Di...
Impact of modulation strategies on power devices loading for 10 MW multilevel wind power converter
DEFF Research Database (Denmark)
Blaabjerg, Frede; Isidori, Andrea; Rossi, Fabio Mario
2012-01-01
in the semiconductor devices of three-level converter adopting continuous and discontinuous PWM modulation strategies. This aspect strongly influences the operation of the converter and directly affects its efficiency. Therefore, a simulation platform is developed in Matlab/Simulink and PLECS environment to analyse...
Pulse-Width-Modulation of Neutral-Point-Clamped Sparse Matrix Converter
DEFF Research Database (Denmark)
Loh, P.C.; Blaabjerg, Frede; Gao, F.
2007-01-01
literature. Addressing the afore-described issues, this paper focuses on the operational mode analysis of a three-level sparse matrix converter implemented using a neutral-point-clamped inversion stage, and the design of a number of PWM and modulation ratio compensation schemes for controlling the converter...
Noise Shaping Filter Compensating PWM Distortion for Fully Digital Amplifier
Yoneya, Akihiko
The full-digital audio amplifiers have several merits such as a high power enabling a small size of the amplifier and digital implementation of the signal processing which allows desired precision of the processing except for the final stage switching amplifiers. Unfortunately, the pulse width modulation (PWM) causes signal distortions because of the non-linearity of the modulation from the viewpoint of the transient response. This paper proposes a compensation method of the PWM distortion with feedback approach. In the noise-shaping filter of the delta-sigma modulator to calculate the pulse codes for the PWM, the distortion caused by the PWM is evaluated and fed it back to compensate the distortion. Eventually the filter is implemented as a state-variable filter with non-linear feedback from the quantizer. The calculation of the filter elements is also described. By using proposed filters, PWM signals with small distortions and small floor noise can be obtained to realize high-fidelity audio amplifiers.
Directory of Open Access Journals (Sweden)
Jeevan Naik
2015-06-01
Full Text Available In this paper, a design and control for the buck-boost converter, i.e., 1-plus-D converter with a positive output voltage, is presented, which combines the 1-plus-D converter and the synchronous rectified (SR buck converter. By doing so, the problem in voltage bucking of the 1-plus-D converter can be solved, thereby increasing the application capability of the 1-plus-D converter. Since such a converter operates in continuous conduction mode inherently, it possesses the nonpulsating output current, thereby not only decreasing the current stress on the output capacitor but also reducing the output voltage ripple. Above all, both the 1-plus-D converter and the SR buck converter, combined into a buck–boost converter with no right-half plane zero, use the same power switches, thereby causing the required circuit to be compact and the corresponding cost to be down. Furthermore, during the magnetization period, the input voltage of the 1-plus-D converter comes from the input voltage source, whereas during the demagnetization period, the input voltage of the 1-plus-D converter comes from the output voltage of the SR buck converter.
Precise Model Analysis for 3-phase High Power Converter using the Harmonic State Space Modeling
DEFF Research Database (Denmark)
Kwon, Jun Bum; Wang, Xiongfei; Blaabjerg, Frede
2015-01-01
This paper presents about the generalized multi-frequency modeling and analysis methodology, which can be used in control loop design and stability analysis. In terms of the switching frequency of high power converter, there can be harmonics interruption if the voltage source converter has a low...
Converter Power Density Increase using Low Inductive Integrated DC-link Capacitor/Bus
DEFF Research Database (Denmark)
Trintis, Ionut; Franke, Toke; Rannested, Bjørn;
2015-01-01
The power losses in switching devices have a direct effect on the maximum converter power. For a voltage source converter, the DC-link bus has a major influence on the power loss and safe operating area of the power devices. The Power Ring Film CapacitorTM integrated with an optimized bus structu...
Converter Power Density Increase using Low Inductive Integrated DC-link Capacitor/Bus
DEFF Research Database (Denmark)
Trintis, Ionut; Franke, Toke; Rannested, Bjørn
2015-01-01
The power losses in switching devices have a direct effect on the maximum converter power. For a voltage source converter, the DC-link bus has a major influence on the power loss and safe operating area of the power devices. The Power Ring Film CapacitorTM integrated with an optimized bus structu...
A High-Precision Control for a ZVT PWM Soft-Switching Inverter to Eliminate the Dead-Time Effect
Directory of Open Access Journals (Sweden)
Baoquan Kou
2016-07-01
Full Text Available Attributing to the advantages of high efficiency, low electromagnetic interference (EMI noise and closest to the pulse-width-modulation (PWM converter counterpart, zero-voltage-transition (ZVT PWM soft-switching inverters are very suitable for high-performance applications. However, the conventional control algorithms intended for high efficiency generally results in voltage distortion. Thus, this paper, for the first time, proposes a high-precision control method to eliminate the dead-time effect through controlling the auxiliary current in the auxiliary resonant snubber inverter (ARSI, which is a typical ZVT PWM inverter. The dead-time effect of ARSI is analyzed, which is distinguished from hard-switching inverters. The proposed high-precision control is introduced based on the investigation of dead-time effect. A prototype was developed to verify the effectiveness of the proposed control. The experimental results shows that the total harmonic distortion (THD of the output current of the ARSI can be reduced compared with that of the hard-switching inverter, because the blanking delay error is eliminated. The quality of the output current and voltage can be further improved by utilizing the proposed control method.
Institute of Scientific and Technical Information of China (English)
吴桂清; 李泓霖; 戴瑜兴; 郑宗伟
2012-01-01
本文针对嵌入式应用中PWM (Pulse-Width Modulation)方式DAC(Digital-to-Analog Converter)和独立DAC芯片选择问题,提出了通过插值方式和多PWM组合方式提高PWM方式DAC分辨率的方法；分析了PWM信号频谱,提出了模拟滤波器设计原则与方法.以MCU(Micro Control Unit)的PWM通道方式实现DAC,经过数据分析证明此方法稳定可靠.%A method that improving the resolution of PWM(Pulse-Width Modulation) mode DAC(Digital-To-Analog Converter) by interpolator was proposed for the problem that PWM mode DAC in embedded applications and how to choose DAC chip. The PWM signal spectrum was analyzed. The design principle and method of analog filter was proposed. The design of High-Resolution DAC using MCU' s(Micro Control Unit) PWM proved that this method is stable and reliable by analysis of experiments.
Synchronised PWM Schemes for Three-level Inverters with Zero Common-mode Voltage
DEFF Research Database (Denmark)
Oleschuk, Valentin; Blaabjerg, Frede
2002-01-01
PWM with synchronous smooth pulses-ratio changing and a quarter-wave symmetry of the voltage waveforms. Three basic versions of both algebraic and trigonometric synchronised PWM have been analysed. Simulations give the behaviour of the proposed methods and show some advantage of synchronised PWM...
Synchronised PWM Schemes for Three-level Inverters with Zero Common-mode Voltage
DEFF Research Database (Denmark)
Oleschuk, Valentin; Blaabjerg, Frede
2002-01-01
PWM with synchronous smooth pulses-ratio changing and a quarter-wave symmetry of the voltage waveforms. Three basic versions of both algebraic and trigonometric synchronised PWM have been analysed. Simulations give the behaviour of the proposed methods and show some advantage of synchronised PWM...
SYNTHESIS OF VOLTAGES OF UNIFORM PWM IN TIME REGULATION
Directory of Open Access Journals (Sweden)
A. G. Stryzhniou
2014-01-01
Full Text Available The article describes a process of synthesis and qualitative assessment of the harmonic composition of voltages of multiple and single PWM pulses in time regulation, being, along with amplitude, frequency and phase method, one of control methods of an asynchronous motor. The main point of time regulation is that a pause after any two single PWM pulses with different polarity or after any two groups of multiple PWM pulses with different polarity changes during a process of regulation. Feature of time regulation is that a motor has fast response in the range of small-signal of control and good linearity of speed-torque characteristics in the whole control range. Analytical expressions of parameters of PWM pulses ai and ti are obtained which allow to simplify considerably a process of formation and implementation of time regulation using tabular or indexed-tabular methods. These expressions allow not only to define voltage amplitude of harmonic but also to perform qualitative assessment of harmonic composition of output voltages at time regulation. It is specified that harmonic frequencies wi = w0/q change in inverse proportion to magnitude of parameter q during a process of regulation and there is a replacement of a fundamental frequency by frequencies of higher harmonics.The offered approach allows to synthesize voltage of uniform single and multiple PWM pulses and to perform their comparative and qualitative analysis and the obtained expressions can be used at modeling of AC motor work. Voltage of multiple PWM pulses which is formed using stepped reference voltage with even quantity of steps in a half period and a pause on a zero level has the best parameters by criterion of a minimum of harmonic components and a maximum of a factor of anharmonicity Kнс at time regulation.
Rowihal, Said Soliman
Both voltage-source and current-source inverters are widely used for supplying three-phase power to induction motor drives, each having their advantages and disadvantages. For high power drives and applications requiring accurate speed and tracking coordination, the synchronous motors are the optimum choice. For constant speed applications of synchronous motor drives, current-source inverters tend to be favored as the motor can usually be operated in the overexcited leading power factor region, thus providing the inverter with sufficient electro-motive force to allow natural commutation. Generally speaking low speed operation of synchronous motors is not satisfactory from naturally commutated current-source inverters. To provide a dynamic range of speed and frequency would require expensive control circuitry and complicates the performance of the drive. The advantage of the voltage-source inverter for the wide range of speed and frequency control herein envisaged is that forced commutation is employed throughout the range and the commutating circuits have been well developed and established. On balance, voltage-source inverters represent a viable compromise for variable-speed three -phase synchronous motor drives including start-up. To investigate the transient response of the voltage -source fed-synchronous motor drives, a digital computer program is developed. The program is based on two models --machine model and inverter model. The machine is represented by a detailed two-axis model which includes the effects due to saliency, damper windings, and machine resistances. The inverter model represents a forced-commutated voltage-source inverter assuming ideal switching devices (thyristors and diodes). To cope with the wide variations of power factor during start-up, a thyristor with a reverse connected parallel diode are integrated as a bidirectional switch. The digital program provides the machine variables of interest (phase currents, field current, damper winding
Analysis of Capacitive Parasitism in PWM Inverter-Fed Motor
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The effects of parasitic capacitance in induction motor system are unnoticed when it is fed from the AC line. but they are obvious when supplied directly from a PWM inverter. Consequently. many parasitic problems occur, such as motor-to-earth leakage current, bearing current, incoming line current distortion and uneven distribution of electrical stresses along the winding. On the ba sis of the uniform transmission line principle, a complete equivalent circuit of the PWM inverter-fed motor system is presented, based on which all the capacitive parasitic problems mentioned above are analyzed and simulated by means of PSPICE. All the results are consistent with the existing ones.
Small-signal, continuous, exact model of PWM voltage regulators
Burkhardt, W.; Maranesi, P.; Varoli, V.
1985-02-01
The small-signal time-continuous open-loop response of buck, boost, and buck-boost pulse-width-modulation (PWM) voltage regulators using MOSFET switches in their power stages is modeled, applying a time-domain sampling theorem (Woodward, 1953) to obtain the Fourier open-loop transfer function corresponding to the comb function describing the response at the chopping instants only. The results are presented graphically along with simplified circuit diagrams of the PWM devices, and the accuracy and computational efficiency of the analytical approach are indicated.
A Novel Soft-Switching Synchronous Buck Converter for Portable Applications
Directory of Open Access Journals (Sweden)
Anup Kumar Panda
2008-01-01
Full Text Available This paper proposes a zero-voltage-transition (ZVT pulse-width-modulated (PWM synchronous buck converter, which is designed to operate at low voltage and high efficiency typically required for portable systems. A new passive auxiliary circuit that allows the main switch to operate with zero-voltage switching has been incorporated in the conventional PWM synchronous buck converter. The operation principles and a detailed steady-state analysis of the ZVT-PWM synchronous converter implemented with the auxiliary circuit are presented. Besides, the main switch and all of the semiconductor devices operate under soft-switching conditions. Thus, the auxiliary circuit provides a larger overall efficiency. The feasibility of the auxiliary circuit is confirmed by simulation and experimental results.
Directory of Open Access Journals (Sweden)
Ramakrishna Manohar Anaparthi
2014-12-01
Full Text Available This paper explains that how to develop and design, control of single phase to three phase drive system. The proposed topology of drive system consisting of two parallel connected rectifiers, inverter and induction motor, connected through inductor and capacitor, where used to produce balanced output to the motor drive. The main objective of this proposed method is to reduce the circulating currents and harmonic distortions at the converter input side, here the control strategy of drive system is PWM (pulse width modulations techniques control strategy, the proposed topology also provides fault compensation in the case of short circuit faults and failure of switches for uninterrupted Power supplies. We also develop and simulate the MATLAB models for proposed drive system, by using MATLAB/ Simulink the output results simulate and observed.
Design of a High Efficiency Boost DC-DC Converter
Institute of Scientific and Technical Information of China (English)
GAO Jing; YAO Suying; XU Jiangtao; SHI Zaifeng
2009-01-01
An accurate circuit of PWM/PFM mode converting and a circuit of auto-adaptively adjusting dimension of power transistor are described. The duty cycle of the signal when the control mode converts can be gained accu-rately by using ratios of currents and capacitances, and an optimal dimension of power transistor is derived with different loads. The converter is designed by 0.35 μm standard CMOS technology. Simulation results indicate that the converter starts work at 0.8 V input voltage. Combined with synchronized rectification, the transfer efficiency is higher than 90% with full load range, and achieves 97.5% at rating output.
LARGE SIGNAL DISCRETE-TIME MODEL FOR PARALLELED BUCK CONVERTERS
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
As a number of switch-combinations are involved in operation of multi-converter-system, conventional methods for obtaining discrete-time large signal model of these converter systems result in a very complex solution. A simple sampled-data technique for modeling distributed dc-dc PWM converters system (DCS) was proposed. The resulting model is nonlinear and can be linearized for analysis and design of DCS. These models are also suitable for fast simulation of these networks. As the input and output of dc-dc converters are slow varying, suitable model for DCS was obtained in terms of the finite order input/output approximation.
Directory of Open Access Journals (Sweden)
Mohammad Sadegh Orfi Yegane
2017-02-01
Full Text Available This paper investigates multi-carrier PWM methods in multi-level inverters. Two new MCPWM methods are introduced. This study proposes a new optimized MCPWM method to improve the output voltage characteristics like THD and LOH. The proposed method is based on variable frequency with a specific range. It means each carrier wave has a determined frequency. It is calling Variable Frequency Triangular Carrier-PWM. MOPSO algorithm is used to optimize the answers. This work considers some different levels of inverters like five, seven and nine levels. The results are compared with SPWM method.
Directory of Open Access Journals (Sweden)
Chetanya Gupta
2014-07-01
Full Text Available The use of multilevel inverters has become popular in recent years for high-power applications. Multilevel Inverters are power converter systems composed by an array of power semiconductor sources that when properly connected and controlled can generate a multistep voltage waveform with variable and controllable frequency, phase and amplitude. This study deals with the comparison of a 7-level inverter with a 9-level inverter system; the voltage source inverters (VSI are modelled and simulated using MATLAB Simulink and the results are presented. The test results verify the effectiveness of the proposed strategy in terms of computational efficiency as well as the capability of the inverter to produce very low distorted voltage with low-switching losses. This research aims to extend the knowledge about the performance of different clamped multilevel inverter through harmonic analysis. Simulations results validate up to the mark performance of the mentioned topologies.
High Efficiency Bi-Directional Converter Used For Renewable System
Directory of Open Access Journals (Sweden)
M. Desal Raja
2014-02-01
Full Text Available This paper presents an Isolated bi-directional converter for renewable system. Voltage stress and current stress was decreses in switches. Power flows in both side. The proposed converter three phase ac voltage to dc voltage, dc voltage to three phase a.c voltage and synchronous the two voltage source. Silicon carbide diodes and bi-directional switches Mosfet’s are used for decreases the switching loss. LC Series resonant converter connected to the high efficiency. This converter power conversion control by the output voltage information.
Directory of Open Access Journals (Sweden)
N. Belhaouchet
2008-03-01
Full Text Available Hysteresis current control is one of the simplest techniques used to control the magnitude and phase angle of motor current for motor drives systems. However, this technique presents several disadvantages such as operation at variable switching frequency which can reveal problems of filtering, interference between the phases in the case of the three-phase systems with insulated neutral connection or delta connection, and irregularity of the modulation pulses which especially causes an acoustic noise on the level of the machine for the high power drive. In this paper, a new technique is proposed for a variable-hysteresis-band controller based on dead beat control applied to three phase voltage source PWM inverters feeding AC motors. Its main aim is firstly ensure a constant switching frequency and secondly the synchronization of modulation pulses using the phase-locked-loop with loop gain compensation in order to ensure a better stability. The behavior of the proposed technique is verified by simulation.
Simulation and Implementation of Quasi Resonant DC-DC Converter
Directory of Open Access Journals (Sweden)
N. Devarajan
2012-01-01
Full Text Available Problem statement: A half-bridge LLC resonant converter with a voltage doubler rectifier has a simple structure and its Zero-Voltage-Switching (ZVS capability is excellent from zero to full load condition. But conduction loss is more due to high circulating energy thus reducing the system efficiency. Moreover a variable frequency control method makes the control circuits more complicated than those using the Pulse Width Modulation (PWM control method. Thus, DC drive has lower efficiency when it operates on light loads. Approach: To improve the efficiency of the DC drive under light loads, a PWM-controlled quasi-resonant converter is proposed .It has simple control circuits and less conduction loss compared to a half-bridge LLC resonant converter under light load conditions. The proposed converter has a half-bridge LLC resonant converter along with an auxiliary circuit. The load regulation of the proposed converter can be achieved by an auxiliary circuit. Thus the proposed converter is expected to be suitable sustaining power module for the efficiency enhancement of DC drives. As the magnetizing inductance of the proposed converter is larger the circulating energy is considerably reduced under light load conditions. In this study the operational principle, design and modeling of QRC DC-DC converters for DC drives are presented. The PWM controlled quasi resonant converter is implemented using PIC microcontroller 16F184A. Results: The capacitor filter in the output is replaced by pi filter to produce DC with minimum ripple. The experimental results and simulation results are compared. This converter has the advantages like reduced number of switches, reduced transformer and filter size, reduced ripple, reduced switching losses, reduced switching stresses and increased power density. Conclusion: The experimental results closely agree with the simulation results.
Decentralized Interleaving of Paralleled Dc-Dc Buck Converters: Preprint
Energy Technology Data Exchange (ETDEWEB)
Johnson, Brian B [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rodriguez, Miguel [National Renewable Energy Laboratory (NREL), Golden, CO (United States)
2017-09-01
We present a decentralized control strategy that yields switch interleaving among parallel connected dc-dc buck converters without communication. The proposed method is based on the digital implementation of the dynamics of a nonlinear oscillator circuit as the controller. Each controller is fully decentralized, i.e., it only requires the locally measured output current to synthesize the pulse width modulation (PWM) carrier waveform. By virtue of the intrinsic electrical coupling between converters, the nonlinear oscillator-based controllers converge to an interleaved state with uniform phase-spacing across PWM carriers. To the knowledge of the authors, this work represents the first fully decentralized strategy for switch interleaving of paralleled dc-dc buck converters.
A new Zero-Current-Transition PWM switching cell
Energy Technology Data Exchange (ETDEWEB)
Grigore, V. [Electronics and Telecommunications Faculty, `Politechnica` University Bucharest (Romania); Kyyrae, J. [Helsinki University of Technology, Otaniemi (Finland): Institute of Intelligent Power Electronics
1997-12-31
In this paper a new Zero-Current-Transition (ZCT) PWM switching cell is presented. The proposed switching cell is composed of the normal hard-switched PWM cell (consisting of one active switch and one passive switch), plus as auxiliary circuit. The auxiliary circuit is inactive during the ON ad OFF intervals of the switches in the normal PWM switch. The transitions between the two states are controlled by the auxiliary circuit. Prior to turn-off, the current through the active switch in the PWM cell is forced to zero, thus the turn-off losses of the active switch are practically eliminated. At turn-on the auxiliary circuit slows down the growing rate of the current through the main switch. Thus, turn-on losses are also very much reduced. The active switch operates under ZCT conditions, the passive switch (diode) has a controlled reverse recovery, while the switch in the auxiliary circuit operates under Zero-Current-Switching (ZCS) conditions. (orig.) 3 refs.
A new Zero-Voltage-Transition PWM switching cell
Energy Technology Data Exchange (ETDEWEB)
Grigore, V. [Electronics and Telecommunications Faculty `Politebuica` University Bucharest (Romania); Kyyrae, J. [Helsinki University of Technology, Otaniemi (Finland): Institute of Intelligent Power Electronics
1997-12-31
In this paper a new Zero-Voltage-Transition (ZVT) PWM switching cell is presented. The proposed switching cell is composed of the normal hard-switched PWM cell (consisting of one active switch and one passive switch), plus an auxiliary circuit (consisting of one active switch and some reactive components). The auxiliary circuit is inactive during the ON and OFF intervals of the switches in the normal PWM switch. However, the transitions between the two states are controlled by the auxiliary circuit. Prior to turn-on, the voltage across the active switch in the PWM cell is forced to zero, thus the turn-on losses of the active switch are practically eliminated. At turn-off the auxiliary circuit behaves like a non-dissipative passive snubber reducing the turn-off losses to a great extent. Zero-Voltage-Transition switching technique almost eliminates switching losses. The active switch operates under ZVT conditions, the passive switch (diode) has a controlled reverse recovery, and the switch in the auxiliary circuit operates under Zero-Current-Switching (ZCS) conditions. (orig.) 6 refs.
Spread Spectrum Modulation by Using Asymmetric-Carrier Random PWM
DEFF Research Database (Denmark)
Mathe, Laszlo; Lungeanu, Florin; Sera, Dezso;
2012-01-01
This paper presents a new fixed carrier frequency random PWM method, where a new type of carrier wave is proposed for modulation. Based on simulations and experimental measurements, it is shown that the spread effect of the discrete components from the motor current spectra and acoustic spectra i...
Simple PWM modulator topology with excellent dynamic behavior
DEFF Research Database (Denmark)
Poulsen, Søren; Andersen, Michael Andreas E.
2004-01-01
This paper proposes a new PWM modulator topology. The modulator is used in switch mode audio power amplifiers, but the topology can be used in a wide range of applications. Due to excellent transient behavior, the modulator is very suited for VRMs or other types of DC-DC or DC-AC applications....
A Series-LC-Filterd Active Trap Filter for High Power Voltage Source Inverter
DEFF Research Database (Denmark)
Bai, Haofeng; Wang, Xiongfei; Loh, Poh Chiang
2016-01-01
current control of the auxiliary converter, which can be challenging considering that the switching harmonics have very high orders. In this paper, an Active Trap Filter (ATF) based on output impedance shaping is proposed. It is able to bypass the switching harmonics by providing nearly zero output...... impedance. A series-LC-filter is used to reduce the power rating and synthesize the desired output impedance of the ATF. Compared with the existing approaches, the compensated frequency range is greatly enlarged. Also, the current reference is simply set to zero, which reduces the complexity of the control...
A Series-LC-Filtered Active Trap Filter for High Power Voltage Source Inverter
DEFF Research Database (Denmark)
Bai, Haofeng; Wang, Xiongfei; Loh, Poh Chiang
2016-01-01
current control of the auxiliary converter, which can be challenging considering that the switching harmonics have very high orders. In this paper, an Active Trap Filter (ATF) based on output impedance shaping is proposed. It is able to bypass the switching harmonics by providing nearly zero output...... impedance. A series-LC-filter is used to reduce the power rating and synthesize the desired output impedance of the ATF. Compared with the existing approaches, the compensated frequency range is greatly enlarged. Also, the current reference is simply set to zero, which reduces the complexity of the control...
Laboratory manual for pulse-width modulated DC-DC power converters
Kazimierczuk, Marian K
2015-01-01
Designed to complement a range of power electronics study resources, this unique lab manual helps students to gain a deep understanding of the operation, modeling, analysis, design, and performance of pulse-width modulated (PWM) DC-DC power converters. Exercises focus on three essential areas of power electronics: open-loop power stages; small-signal modeling, design of feedback loops and PWM DC-DC converter control schemes; and semiconductor devices such as silicon, silicon carbide and gallium nitride. Meeting the standards required by industrial employers, the lab manual combines program
DEFF Research Database (Denmark)
Song, Zhanfeng; Tian, Yanjun; Yan, Zhuo
2016-01-01
characteristic is highly dynamic behaviors, the proposed control strategy can present comparably enhanced transient performance. Furthermore, excellent steady-state power performance can also be observed when the proposed control scheme is adopted. In addition, another attractive feature lies in its robust......This paper proposed a direct power control strategy for three-phase two-level voltage-source rectifiers based on extended-state observation. Active and reactive powers are directly regulated in the stationary reference frame. Similar to the family of predictive controllers whose inherent...... control strategy, the vector-oriented control scheme and the proposed strategy, which demonstrate the superiority of the proposed scheme....
Zhang, Jianghan; Luo, Hui; Zhao, Jin; Wu, Feng
2015-02-01
This paper develops a novel method for the detection and isolation of open-transistor faults in voltage-source inverters feeding induction motors. Based on analyzing the load currents trajectories after Concordia transformation, six diagnostic signals each of which indicates a certain switch are extracted and a fuzzy rule base is designed to perform fuzzy reasoning in order to detect and isolate 21 fault modes including single- and double-transistor faults. In addition, the fuzzy rules are rearranged and each of them is set to a reasonable value representing the fault modes. The simulation and experiment are carried out to demonstrate the effectiveness of the proposed fuzzy approach.
Design of A 0.5V Op-Amp Based on CMOS Inverter Using Floating Voltage Sources
Wang, Jun; Lee, Tuck-Yang; Kim, Dong-Gyou; Matsuoka, Toshimasa; Taniguchi, Kenji
2008-01-01
This letter presents a 0.5 V low-voltage op-amp in a standard 0.18 µm CMOS process for switched-capacitor circuits. Unlike other two-stage 0.5 V op-amp architectures, this op-amp consists of CMOS inverters that utilize floating voltage sources and forward body bias for obtaining high-speed operation. And two improved common-mode rejection circuits are well combined to achieve low power and chip area reduction. Simulation results indicate that the op-amp has an open-loop gain of 62 dB, and a h...
DEFF Research Database (Denmark)
Xin, Zhen; Mattavelli, Paolo; Yao, WenLi
2017-01-01
LCL filters feature low inductance; thus, the injected grid current from an LCL-filtered Voltage Source Inverter (VSI) can be easily distorted by grid voltage harmonics. This problem is especially tough for the control system with Inverter-side Current Feedback (ICF), since the grid current...... cause noise amplification. In light of the above issue, this paper develops a simple method for the ICF control system to mitigate the grid current harmonics without extra sensors. In the proposed method, resonant harmonic controllers and an additional compensation loop are adopted at the same time...
Directory of Open Access Journals (Sweden)
Riyadh G. Omar
2014-12-01
Full Text Available Four-leg voltage source inverter is an evolution of the three-leg inverter, and was ought about by the need to handle the non-linear and unbalanced loads. In this work Matlab/ Simulink model is presented using space vector modulation technique. Simulation results for worst conditions of unbalanced linear and non-linear loads are obtained. Observation for the continuity of the fundamental inverter output voltages vector in stationary coordinate is detected for better performance. Matlab programs are executed in block functions to perform switching vector selection and space vector switching.
Hernandez, Gabriel D.
2016-01-01
Approved for public release; distribution is unlimited For an Energy Management System (EMS)-controlled microgrid that uses a single-phase voltage source inverter (VSI) configuration to supply power for AC loads from DC energy storage devices, the DC link connecting the VSI to the DC energy storage devices experiences a voltage ripple that is a second-order harmonic of the AC frequency. When the EMS has a battery bank as the only DC energy storage device, the DC link voltage ripple causes ...
Low Loss Passive Snubber in Push-pull Voltage Source Inverter%一种用于推挽式电压型逆变器的低损耗无源吸收电路
Institute of Scientific and Technical Information of China (English)
伍家驹; 杉本英彦
2006-01-01
A low loss passive snubber is developed for the PWM push-pull Voltage Source Inverter (VSI). In order to avoid the superposition of the high frequency discharge energy on the output voltage, an independent discharge circuit is introduced to feed back part of the energy in the capacitor to DC source. Due to the voltage clamp on the capacitor, there is,for the doubled voltage of the push-pull circuit, no additional loss in the snubber. Details of design and a 200V DC input,30kW VSI application example are also presented.Experimental results show that the circuit topology is a good choice in low loss snubber design.%提出并实现了一种推挽式PWM电压型逆变器用无源吸收电路;设有独立的放电回路让缓冲电容器上的能量部分地回馈到直流电源中,高频放电能量不会叠加在输出电压上;缓冲电容器的电压被钳位,使得推挽电路特有的倍压不会在吸收电路上造成额外的损耗.给出吸收电路参数的设计准则和计算实例,在200VDC和30kW级的中压中功率逆变装置中发挥了推挽拓扑的优点.理论分析和实验验证了所提方法的有效性.
National Research Council Canada - National Science Library
Yoshida, Masanobu; Hiraki, Eiji; Nakaoka, Mutsuo
2003-01-01
This paper presents a novel three-phase voltage source type soft-switching inverter using the main and auxiliary IGBT power module packages in order to reduce their switching power losses as well...
Institute of Scientific and Technical Information of China (English)
刘胜文; 包广清; 范少伟; 刘峻; 李正元
2011-01-01
The low-voltage ride-through (LVRT) capability of a MW-Level variable speed wind turbine with a direct-driven permanent magnet synchronous generator (PMSG) is investigated. In this paper a novel DC link voltage control scheme was proposed to prevent DC link dynamic voltage from too high value. Comparison of the traditional control method, the machine-side converter uses a double control with the current inner loop and the DC link voltage outer loop; and network-side converter has dual-loop control with grid current inner loop and generator speed outer ring, to output the best energy. The simulation results show that the new control method can effectively improve the low voltage ride through capability of variable speed wind turbines with PMSG.%通过对兆瓦级双PMW直驱式永磁同步风力发电机(PMSG)系统低电压穿越能力的研究,本文提出了一种改进的功率变换控制方法来抑制过高的直流母线动态电压.与传统控制方法相比,该方法中机侧整流器采用电流内环、直流母线电压外环的双闭环控制结构,同时网侧逆变器采用电网电流为内环、发电机转速为外环的双闭环控制结构,保证系统输出最佳能量.仿真结果表明本文提出的控制方法有效提高了PMSG系统的低电压穿越能力.
Diode-clamped multilevel converters with integrable gate-driver power-supply circuits
Busquets Monge, Sergio; Rocabert Delgado, Joan; Crébier, Jean-Christophe; Peracaula Roura, Joan
2009-01-01
International audience; Recent contributions in pulse width modulations (PWM) for multilevel diode-clamped converters enable the use of these converters with passive front-ends, any number of levels, and small dc-link capacitors. Highly compact converters designs based on these topologies can be envisioned. However, the design of the gate-driver power-supply for the multiple controlled semiconductor devices remains an important issue to be addressed. This paper focuses on the design of such c...
DEFF Research Database (Denmark)
Vasquez, Juan Carlos; Guerrero, Josep M.; Savaghebi, Mehdi;
2013-01-01
Power electronics based MicroGrids consist of a number of voltage source inverters (VSIs) operating in parallel. In this paper, the modeling, control design, and stability analysis of parallel connected three-phase VSIs are derived. The proposed voltage and current inner control loops and the mat......Power electronics based MicroGrids consist of a number of voltage source inverters (VSIs) operating in parallel. In this paper, the modeling, control design, and stability analysis of parallel connected three-phase VSIs are derived. The proposed voltage and current inner control loops...... and the mathematical models of the VSIs are based on the stationary reference frame. A hierarchical control scheme for the paralleled VSI system is developed comprising two levels. The primary control includes the droop method and the virtual impedance loops, in order to share active and reactive power. The secondary...... control restores the frequency and amplitude deviations produced by the primary control. Also, a synchronization algorithm is presented in order to connect the MicroGrid to the grid. Experimental results are provided to validate the performance and robustness of the parallel VSI system control...
Three-phase Resonant DC-link Converter
DEFF Research Database (Denmark)
Munk-Nielsen, Stig
no additional power electric components is eliminating the high voltage peaks associated with the resonant circuit. The resonant link voltage peaks are limited below 2.1 times the DC link voltages. A new principle eliminating former resonant converter stability problems are proposed, implemented and tested......The purpose of the project is to develop a three-phase resonant converter suitable for standard speed drives. The motivation for working with resonant converters is found in the problem of the standard converter type used today. In standard converter type Pulse Width Modulated-Voltage Source....... The high speed of the switches cannot be fully utilizied. By using a parallel resonant converter the switching happens at low or zero voltage which reduses switch losses. The dv/dt is controlled by the resonant circuit, and it is therefore reduced significantly. The perspective using a resonant converter...
Analysis of Dither in PWM Control on Electro-hydraulic Proportional Valve
Directory of Open Access Journals (Sweden)
Guoping LIU
2013-11-01
Full Text Available Plus with modulation (PWM is widely used in proporational control systems for it is efficient, flexible and anti-interference. Due to the friction and hysteresis of electromagnet, hysteresis exists when hydraulic valve in steady-state, and hysteresis influences the dynamic characteristics of the valve seriously,the hysteresis can be improved by superimposing dithers with certain frequency and amplitude to the valve coil. Aiming at the character of anti-unloading power driver circuit ,this paper analyzed the parasitic dither which exists in ±24V PWM control，besides，the experiment shows that in a high frequency PWM, dither with independent frequency and amplitude can be generated by changing the frequency of the PWM, in this way, the dithers and average current of coil can be adjusted separately by changing PWM frequency and PWM duty cycle.
A Study on Power Quality Improvement in PWM Controlled AC Voltage Controller
Directory of Open Access Journals (Sweden)
Ahmet ALTINTAŞ
2009-04-01
Full Text Available A lot of topologies of pulse-width modulated (PWM-AC controllers for single-phase and three-phase systems are proposed up to date. PWM-AC controllers have important advantages compared with the phase-controlled AC controllers using thyristors and triacs. The PWM-AC controller has sinusoidal current waveforms, smaller THD values, better power factor, faster dynamics, and smaller input/output filter. This article presents a novel control technique for application to PWM-AC controllers with ability of generating fewer harmonics. In the proposed control method, both the traditional AC voltage controllers and the PWM-AC controllers are combined; and smaller THD values are obtained. Thus, the harmonic pollution in the power system will be reduced; and consequently, the power quality will be increased. For this purpose, computer simulations are performed in order to investigate the proposed controller performance. The obtained results are compared with the conventional PWM-AC controller.
The Analysis and Compensation of Output Error for Voltage Source PWM Inverter%电压型PWM逆变器输出误差分析及其补偿
Institute of Scientific and Technical Information of China (English)
陈硕; 薛昭武
2001-01-01
由于死区时间和电力电子器件IGBT非理想特性的影响，PWM逆变器存在输出误差，使得众多的调速方案在低速运行时性能不佳或无法实现调速。本文详细分析死区时间和IGBT非理想特性对输出电压的影响，提出测量IGBT非理想特性方法和输出误差补偿法，并通过实验验证了误差补偿法的有效性。%Because a tWM inverter has an output error due to the dead time and the non-tdeal characteristic of IGBT, a number of variable speed schemes cannot obtain a good performance or operate at low speed. This paper analyzes the influence of the dead time and the non-ideal characteristic on the output voltage in detail, and proposes a measurement of IGBT and a compensating algorithm for the inverter. The validity of the proposed method has been verified by experimentation.
Synthesis of Voltages of Multiple Uniform PWM, Generated by Trapezoidal and Sinusoidal Functions
Directory of Open Access Journals (Sweden)
A. Ctryzhniou
2013-01-01
Full Text Available The problem of synthesis and qualitative estimation of the harmonic composition of voltages of multiple uniform PWM pulses generated by trapezoidal and sinusoidal functions is considered. Analytical expressions for PWM pulses parameters ai and ti have been received and they can be used for program-based generation of multiple uniform PWM, determination of n-harmonic magnitude in pulse-width regulation and AC motor operation simulation.
Controlling DC Motor using Microcontroller (PIC16F72) with PWM
Shruti Shrivastava, Jageshwar Rawat, Amit Agrawal
2012-01-01
Motion control plays a vital role in industrial atomization. Different types of motors AC, DC, SERVO or stepper are used depending upon the application; of these DC motors are widely used because of easier controlling. Among the different control methods for DC motor armature voltage control method using pulse width modulation (PWM) is best one. We can realize the PWM using H-bridge built with IGBT switches or transistors. To generate PWM signals we use PIC16F7...
High-Frequency Link Inverter for Fuel Cells Based on Multiple-Carrier PWM （to continue）
Institute of Scientific and Technical Information of China (English)
无
2004-01-01
C. Operation of a PWM Cycloconverter The concepts in Section Ⅱ-B, present a progression of solutions to known design difficulties. To incorporate these benefits and eliminate the redundant conversion step shown in Fig. 6, we propose the PWM cycloconverter shown in Fig. 7. It will be shown in Section Ⅲ. that the conventional PWM inverter can be unified through a multiple-carrier PWM framework. The control concept introduced is extended to demonstrate that multiple-carrier PWM methods lead to HF link inverters that are nearly as simple to control as conventional PWM inverters.
Energy Technology Data Exchange (ETDEWEB)
Svensson, Jan [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Electric Power Engineering
1996-12-01
In this paper the hybrid wind farm connected to a weak grid is investigated. By combining different electrical wind power plant systems a cost-efficient solution is obtained. The point of common connection voltage level can be controlled by injecting reactive power from a phase-compensating capacitor battery and a voltage source inverter (VSI). If the short-circuit impedance ratio is lower than 1, the demanded reactive power injection to keep the voltage at nominal level is unrealistic. For short-circuit impedance ratios of 2 or higher the demanded reactive power level is acceptable. When using both induction generators and thyristor inverters the reactive power injector VSI size should be about 0.2 pu. If the hybrid farm consists of THYs, IGs and VSIs and the active power is equally shared between the systems, the VSI had to be scaled up by 5% to handle both active and reactive power. 7 refs, 10 figs, 2 tabs
Sinthusonthishat, S.; Kinnares, V.
This paper proposes a new modulation scheme providing unbalanced output terminal voltages of a standard three-leg voltage source inverter (VSI) for unsymmetrical type two-phase induction motors. This strategy allows a control method of the output voltages with typically constant V/Hz for a main winding and with voltage boost to compensate magnitude of current for an auxiliary winding. Harmonic voltage characteristics and the motor performance are investigated under a wide range of operating conditions. Practical verification is presented to confirm correctness and capabilities of the proposed technique. All results are compared to those of a conventional two-leg half bridge topology. The results show that the simulation results well agree with the experimental ones, and also the proposed scheme is superior to the conventional drive.
Tutkun, Nedim; Moses, Anthony J.
2004-12-01
Recently the strip wound toroidal cores have increasingly been used in switching mode and uninterruptible power supplies for a wide range of industrial applications. Therefore, the prediction of iron loss increase in such magnetic cores energised by non-sinusoidal voltage excitation is important step in the design of electromagnetic devices. In this investigation, a loss increase was estimated by determination of unknown constants in a previously developed loss separation model using genetic algorithms. Also the skin effect of flux density was taken into account for estimation of power loss under pulse width modulated voltage sources. The results obtained are in good agreement with the measured results in wound toroids at various flux densities.
DEFF Research Database (Denmark)
Vasquez, Juan Carlos; Guerrero, Josep M.; Savaghebi, Mehdi
2011-01-01
and discussed. Experimental results are provided to validate the performance and robustness of the VSIs functionality during Islanded and grid-connected operations, allowing a seamless transition between these modes through control hierarchies by regulating frequency and voltage, main-grid interactivity......Power electronics based microgrids consist of a number of voltage source inverters (VSIs) operating in parallel. In this paper, the modeling, control design, and stability analysis of three-phase VSIs are derived. The proposed voltage and current inner control loops and the mathematical models...... the frequency and amplitude deviations produced by the primary control. And the tertiary control regulates the power flow between the grid and the microgrid. Also, a synchronization algorithm is presented in order to connect the microgrid to the grid. The evaluation of the hierarchical control is presented...
Performance optimization of a photovoltaic chain conversion by the PWM control
Rezoug, M. R.; Chenni, R.
2017-02-01
The interest of the research technique of maximum power point tracking, exposed by this article, lays in the fact of work instantly on the real characteristic of the photovoltaic module. This work is based on instantaneous measurements of its terminals' current & voltage as well as the exploitation of the characteristic "Power - Duty Cycle" to define rapidly the Duty cycle in which power reaches its maximum value. To ensure instantaneous tracking of the point of maximum power, we use "DC/DC Converter" based on "Pulse Wave Modulation's (PWM) Command" controlled by an algorithm implanted in a microcontroller's memory. This algorithm responds to the quick changes in climate (sunlight and temperature). To identify the control parameters "VPV & IPV" at any change in operating conditions, sensors are projected. this algorithm applied to the Duty cycle of the static converter enables the control of power supplied by the photovoltaic generator thanks to oscillatory movement around the MPP. Our article highlights the importance of this technique which lays in its simplicity and performance in changing climatic conditions. This efficiency is confirmed by experimental tests and this technique will improve its predecessors.
ABNORMAL AND TRANSIENT MODES OF THE CONVERTER BOOSTER TYPE FOR DC TRACTION SUBSTATIONS
Directory of Open Access Journals (Sweden)
Yu. P. Goncharov
2008-12-01
Full Text Available The results of analytical research and computer design of the anomalous, steady-state and transitional modes related to the resonance in the input filter of voltage added converter based on IGBT with the PWM are presented. The ways of resonance removal by both the control means and the power blocks, combined with the overvoltage protection, are offered.
Hexuple-Inverter Configuration for Multilevel Nine-Phase Symmetrical Open-Winding Converter
DEFF Research Database (Denmark)
Padmanaban, Sanjeevi Kumar; Bhaskar, Mahajan Sagar; Maroti, Pandav Kiran
2016-01-01
Hexuple-inverter configuration for multilevel nine-phase symmetrical open-winding ac converter is articulated in this work. Power modular unit consists of six classical three-phase voltage source inverters (VSI). Each VSI includes one bi-directional device (MOSFET/IGBT) per each phase and link...
Hexuple-Inverter Configuration for Multilevel Nine-Phase Symmetrical Open-Winding Converter
DEFF Research Database (Denmark)
Padmanaban, Sanjeevi Kumar; Bhaskar, Mahajan Sagar; Maroti, Pandav Kiran
2016-01-01
Hexuple-inverter configuration for multilevel nine-phase symmetrical open-winding ac converter is articulated in this work. Power modular unit consists of six classical three-phase voltage source inverters (VSI). Each VSI includes one bi-directional device (MOSFET/IGBT) per each phase and link to...
DEFF Research Database (Denmark)
Beres, Remus Narcis; Wang, Xiongfei; Blaabjerg, Frede;
2014-01-01
In this paper a comprehensive analysis of three passive damping methods is done under parallel operation of multiple current controlled voltage source converters. One could argue that a well damped LCL filter with no peaking in the output impedance and stable designed controllers will turn into s...
A novel double quad-inverter configuration for multilevel twelve-phase open-winding converter
DEFF Research Database (Denmark)
Padmanaban, Sanjeevi Kumar; Blaabjerg, Frede; Wheeler, Patrick William
2016-01-01
This paper describes a novel proposal of double quad-inverter configuration for multilevel twelve-phase open-winding ac converter. Modular power units are developed from reconfigured eight classical three-phase voltage source inverters (VSIs). Each VSI has one additional bi-directional switching ...
Directory of Open Access Journals (Sweden)
Vargese Jegathesan
2008-01-01
Full Text Available This paper presents an efficient and reliable Genetic Algorithm-based solution for Specific Harmonic Elimination (SHE switching pattern. This method eliminates considerable amount of lower order line voltage harmonics in Pulse Width Modulation (PWM inverter. The determination of pulse pattern for the elimination of some lower order harmonics of a PWM inverter necessitates solving a system of nonlinear transcendental equations. Genetic Algorithm is used to solve nonlinear transcendental equations for PWM-SHE. In this proposed method, harmonics up to 17th are eliminated using Genetic Algorithm without using Dual transformer. Simulations using Matlab 7.0 and PSIM 6.1 are carried out so as to validate the solution.
Closed Loop Control of Soft Switched Interleaved Buck Converter
Directory of Open Access Journals (Sweden)
R. Shenbagalakshmi
2012-06-01
Full Text Available Design, Modeling and Simulation of a closed loop control is presented for Interleaved Buck Converter with Soft Switching. The features of the closed loop system are to reduce the switching losses and load current sharing among the parallel connected converters. The control system of the converter is designed using PWM technique. In order to improve the transient response and dynamic stability of the converters, the controller parameters are designed based on current mode control. Resonant components thus designed enable the application of zero current switching for both the converters connected in parallel thereby maintaining greater efficiency and minimizing voltage and current oscillations. The system analysis, design and performance are verified through simulation using MATLAB/Simulink environment. The simulation approach reveals the high speed dynamic performance of the closed loop system designed using robust PID controller. The laboratory prototype of the Buck converter is developed to verify the controller platform using PIC16F877A microcontroller.
A Dual-Mode Step-up DC/DC Converter IC with Current-Limiting and EMI Reduction Techniques
Institute of Scientific and Technical Information of China (English)
Wan-Rone Liou; Chun-Ting Kuo; Mei-Ling Yeh; Ping-Hsing Chen; Marynelle L. Z. Rosales
2008-01-01
This paper presents a novel dual-mode step-up (boost) DC/DC converter. Pulse-frequency modulation (PFM) is used to improve the efficiency at light load. This converter can operate between pulse-width modulation (PWM) and pulse-frequency modulation. The converter will operate in PFM mode at light load and in PWM mode at heavy load. The maximum conversion efficiency of this converter is 96%. The conversion efficiency is greatly improved when load current is below 100 mA. Additionally, a soft-start circuit and a variable-sawtooth frequency circuit are proposed in this paper. The former is used to avoid the large switching current at the start up of the converter and the latter is utilized to reduce the EMI of the converter.
Institute of Scientific and Technical Information of China (English)
Abdolkhalegh Hamidi; Jamal Beiza; Ebrahim Babaei; Sohrab Khanmohammadi
2016-01-01
An input-output signal selection based on Phillips-Heffron model of a parallel high voltage alternative current/high voltage direct current (HVAC/HVDC) power system is presented to study power system stability. It is well known that appropriate coupling of inputs-outputs signals in the multivariable HVDC-HVAC system can improve the performance of designed supplemetary controller. In this work, different analysis techniques are used to measure controllability and observability of electromechanical oscillation mode. Also inputs–outputs interactions are considered and suggestions are drawn to select the best signal pair through the system inputs-outputs. In addition, a supplementary online adaptive controller for nonlinear HVDC to damp low frequency oscillations in a weakly connected system is proposed. The results obtained using MATLAB software show that the best output-input for damping controller design is rotor speed deviation as out put and phase angle of rectifier as in put. Also response of system equipped with adaptive damping controller based on HVDC system has appropriate performance when it is faced with faults and disturbance.
Institute of Scientific and Technical Information of China (English)
刘昇; 徐政; 唐庚; 华文; 薛英林
2013-01-01
Based on the fundamental frequency mathematical model of VSC-HVDC power transmission in d-q rotating dq rotary coordinate system, the electromechanical transient mathematical equations of VSC-HVDC power transmission are summarized, afterwards a electromechanical transient model for VSC-HVDC power transmission is achieved based on user-defined function of PSS/E and the achieved model is compared with the precise electromagnetic transient model for VSC-HVDC power transmission in PSCAD, and simulation results show that the steady state power flows from the two models are very similar and their dynamic characteristics are highly consistent each other, thus the effectiveness and accuracy of the achieved electromechanical transient model for VSC-HVDC power transmission are verified. Finally, using the achieved model the application of VSC-HVDC power transmission in actual large-scale multi-infeed HVDC power transmission system is researched, and research results show that using VSC-HVDC power transmission technology the commutation failure occurred in traditional HVDC power transmission system can be radically resolved.% 以VSC-HVDC在dq旋转坐标系下的基频数学模型为基础，总结了 VSC-HVDC 的机电暂态数学方程。之后基于 PSS/E 自定义模型功能实现了 VSC-HVDC 机电暂态模型，并将该模型和PSCAD中VSC-HVDC电磁暂态精确模型进行了对比，仿真结果表明两者的稳态潮流十分接近，动态特性具有很好的一致性，从而验证了VSC-HVDC机电暂态模型的有效性和准确性。最后基于该模型对VSC-HVDC 在实际大规模多直流馈入系统中的应用进行了研究，结果表明 VSC-HVDC 从根本上解决了传统直流输电的换相失败问题。
VSC-HVDC输电系统的性能分析%Performance Analysis of Voltage Source Converter Based HVDC Transmission System
Institute of Scientific and Technical Information of China (English)
姜建国; 颜廷阁
2012-01-01
VSC-HVDC is a new type of power transmission technology developed based on traditional HVDC. Aiming at the features of VSC-HVDC system, e. g. , good controllability, compact modular design and easy to construct multi-terminal DC systems, etc, the working principle and dynamic performance are described. Meanwhile, dynamic performance analysis on the faults of 100 kV and 200 MV VSC-HVDC transmission systems is investigated. The simulation results by using Matlab/Simulink verify that the system possesses good performance and effective decoupling control under active and reactive power variations and fault conditions.%电压源型高压直流输电( VSC-HVDC)技术是在传统直流输电基础上发展起来的一种新型输电技术.针对VSC-HVDC系统具有良好的可控性、紧凑的模块化设计、容易构成多端直流系统等特点,阐述了其工作原理及动态性能.同时,探讨了100 kV、200 MVVSC-HVDC输电系统故障的动态性能分析,并采用Matlab/Simulink进行了仿真试验.试验结果证实了该系统在有功与无功变化以及在故障条件下具有性能良好和解耦控制有效的特性.
A low noise high efficiency buck DC-DC converter with sigma-delta modulation
Energy Technology Data Exchange (ETDEWEB)
Cai Shujiang; Pi Changming; Yan Wei; Li Wenhong, E-mail: wenhongli@fudan.edu.cn [State Key Laboratory of ASIC and Systems, Fudan University, Shanghai 201203 (China)
2011-07-15
Some research efforts to improve the efficiency and noise performance of buck DC-DC converters are explored. A carefully designed power MOSFET driver, including a dead time controller, discontinuous current mode (DCM) controller and gate width controller, is proposed to improve efficiency. Instead of PWM modulation, sigma-delta modulation is introduced into the feedback loop of the converter to move out the clock-referred harmonic spike. The proposed converter has been designed and fabricated by a 0.35 {mu}m CMOS process. Measured results show that the peak efficiency of the converter can reach 93% and sigma-delta modulation suppresses the harmonic spike by 30 dB over PWM modulation. (semiconductor integrated circuits)
Hwu, K. I.; Tu, W. C.; Wang, C.R.
2013-01-01
A photovoltaic energy conversion system, constructed by high step-up converter with hybrid maximum power point tracking (HMPPT), is presented. A voltage converter with a high voltage conversion ratio is proposed, which is simple in circuit and easy in control. After this, such a converter operating with a suitable initial duty cycle of the pulsewidth-modulated (PWM) control signal, together with the proposed HMPPT algorithm combining the fractional open-circuit voltage method and the incremen...
Development of a PWM precision spraying controller for unmanned aerial vehicles
This paper presents a new pulse width modulation (PWM) controller for unmanned aerial vehicle (UAV) precision sprayer for agriculture using a TL494 fix-frequency pulse width modulator together with a data acquisition board and developed software. The PWM controller was implemented through the guidan...
CONTROL TECHNIQUES FOR VARIOUS BIPOLAR PWM STRATEGIES OF THREE PHASE FIVE LEVEL CASCADED INVERTER
Directory of Open Access Journals (Sweden)
C. R. BALAMURUGAN
2015-07-01
Full Text Available This paper presents different types of bipolar Pulse Width Modulation (PWM strategies for the chosen Cascaded MultiLevel Inverter (CMLI. The main purpose of MLI is to use power semiconductor devices of lower voltage ratings to realize high voltage levels at inverter output. Due to their ability to obtain refined output voltage waveforms, reduced Total Harmonic Distortion (THD and reduced EMI problems by reducing the switching dv/dt. In this paper, a three phase CMLI is controlled with Sinusoidal PWM strategy with Phase Disposition PWM (PDPWM, Phase Opposition and Disposition PWM (PODPWM, Alternative Phase Opposition and Disposition PWM (APODPWM, Phase Shift PWM (PSPWM and hybrid modulation strategy and the variation of THD in their outputs are observed by varying the modulation index. Simulations are performed using MATLAB-SIMULINK. It is observed that APODPWM and PSPWM provide output with relatively low distortion. It is also seen that PS, APOD and hybrid PWM are found to perform better since they provide relatively higher fundamental RMS output voltage. From hardware results it is seen that POD PWM provides output with relatively low distortion. It is also observed that PSPWM is found to perform better since it provide relatively higher fundamental RMS output voltage.
High flexibility and low cost digital implementation for modern PWM strategies
DEFF Research Database (Denmark)
Mathe, Laszlo; Sera, Dezso; Kerekes, Tamas
2011-01-01
like AZSPWM, NSPWM, or ACRPWM. By using a conventional PWM unit from a microcontroller, these modern modulation techniques are often difficult, or even impossible, to implement. The proposed method can be used to implement PWM strategies even for those microcontrollers which are not equipped...
Influence of PWM Modes on Commutation Torque Ripples in Sensorless Brushless DC Motor Control System
Institute of Scientific and Technical Information of China (English)
ZHANGXiang－jun; CHENBo－shi; 等
2001-01-01
This paper introduces four PWM modes used in the sensorless brushless DC motor control system,analyzes their different influences on the commutation torque ripple in detail,and selects the best PWM mode in four given types to reduce commutation torque ripple of Brushless OC( BLDC) motors,Simulation and experimental results show that the selection is correct and practical.
A dual voltage control strategy for single-phase PWM converters with power decoupling function
DEFF Research Database (Denmark)
Tang, Yi; Qin, Zian; Blaabjerg, Frede
2014-01-01
on a symmetrical half bridge circuit is proposed to decouple the ripple power so that balanced instantaneous power flow is assured between source and load, and the required dc-link capacitance can be dramatically reduced. For proper closed-loop regulation, the small signal modeling of the proposed system...... is presented, and a dual voltage control strategy is then proposed, which comprises one voltage loop implemented in the synchronous reference frame for active power balancing, and another one implemented in the harmonic reference frame for ripple power compensation. Special attention is given to the bandwidth...
Energy Technology Data Exchange (ETDEWEB)
Bolognesi, P.; Carrara, G.; Casini, D.; Taponecco, L. [Pisa Univ. (Italy). Dipt. di Sistemi Elettrici e Automazione
1995-12-31
A possible way to extend a previously theoretically examined local spectral approximation strategy to the case of three-phase inverters is reported, and the first results obtained from a theoretical research concerning the elimination of entire harmonic families by imposing simple structural properties to the output waveforms are then presented. 1 ref, 10 figs, 1 tab
DEFF Research Database (Denmark)
Kouchaki, Alireza; Niroumand, Farideh Javidi; Haase, Frerk;
2015-01-01
circuit is used to provide the inductor current harmonic spectrum. Therefore, using the harmonic spectrum, the low and high frequency copper losses are calculated. The high frequency minor B-H loops in one switching cycle are also analyzed. Then, the loss map provided by the measurement setup is used...
High flexibility and low cost digital implementation for modern PWM strategies
DEFF Research Database (Denmark)
Mathe, Laszlo; Sera, Dezso; Kerekes, Tamas
2011-01-01
In this paper a new low cost technique for PWM strategy implementation is presented. The proposed technique does not require dedicated hardware PWM units, thus offering higher flexibility of use. Furthermore, the aforementioned method eases the digital implementation of modern modulation methods ...... with hardware PWM unit. The experimental results show that this new technique is suitable to replace traditional implementation methods with minimum computational overhead, with the benefit of high flexibility, lower cost and faster code development.......In this paper a new low cost technique for PWM strategy implementation is presented. The proposed technique does not require dedicated hardware PWM units, thus offering higher flexibility of use. Furthermore, the aforementioned method eases the digital implementation of modern modulation methods...
New Configuration of Traction Converter with Medium-Frequency Transformer: Primary Part
Directory of Open Access Journals (Sweden)
Vojtech Blahnik
2008-01-01
Full Text Available This paper deals with new configuration of the traction converter with medium-frequency transformer intended for ac trolley wire fed locomotives. It is concerned to the primary serially connected single-phase voltage-source active rectifiers, which are directly connected to the trolley wire. This contribution presents the proposed control of the primary active rectifiers, simulation and experimental results of designed low-voltage laboratory prototype of converter of rated power of 12kW.
Lee, Ho-Young; Kang, In Man; Shon, Chae-Hwa; Lee, Se-Hee
2015-05-01
A variable inductor with magnetorheological (MR) fluid has been successfully applied to power electronics applications; however, its thermal characteristics have not been investigated. To evaluate the performance of the variable inductor with respect to temperature, we measured the characteristics of temperature rise and developed a numerical analysis technique. The characteristics of temperature rise were determined experimentally and verified numerically by adopting a multiphysics analysis technique. In order to accurately estimate the temperature distribution in a variable inductor with an MR fluid-gap, the thermal solver should import the heat source from the electromagnetic solver to solve the eddy current problem. To improve accuracy, the B-H curves of the MR fluid under operating temperature were obtained using the magnetic property measurement system. In addition, the Steinmetz equation was applied to evaluate the core loss in a ferrite core. The predicted temperature rise for a variable inductor showed good agreement with the experimental data and the developed numerical technique can be employed to design a variable inductor with a high-frequency pulsed voltage source.
Energy Technology Data Exchange (ETDEWEB)
Lee, Ho-Young; Kang, In Man, E-mail: imkang@ee.knu.ac.kr [School of Electronics Engineering, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Shon, Chae-Hwa [Korea Electrotechnology Research Institute, Changwon 642-120 (Korea, Republic of); Lee, Se-Hee, E-mail: shlees@knu.ac.kr [Department of Electrical Engineering, Kyungpook National University, Daegu 702-701 (Korea, Republic of)
2015-05-07
A variable inductor with magnetorheological (MR) fluid has been successfully applied to power electronics applications; however, its thermal characteristics have not been investigated. To evaluate the performance of the variable inductor with respect to temperature, we measured the characteristics of temperature rise and developed a numerical analysis technique. The characteristics of temperature rise were determined experimentally and verified numerically by adopting a multiphysics analysis technique. In order to accurately estimate the temperature distribution in a variable inductor with an MR fluid-gap, the thermal solver should import the heat source from the electromagnetic solver to solve the eddy current problem. To improve accuracy, the B–H curves of the MR fluid under operating temperature were obtained using the magnetic property measurement system. In addition, the Steinmetz equation was applied to evaluate the core loss in a ferrite core. The predicted temperature rise for a variable inductor showed good agreement with the experimental data and the developed numerical technique can be employed to design a variable inductor with a high-frequency pulsed voltage source.
Institute of Scientific and Technical Information of China (English)
樊英杰; 张开如; 韩璐; 狄东照; 鲁金生
2015-01-01
The topology structure of three-phase voltage-source PWM rectifier( VSR) and the basic principle of voltage oriented control( VOC) were presented.In view of the shortage of the traditional space vector pulse width modulation ( SVPWM) algorithm applied in three-phase VSR, this paper puts forward an optimized SVPWM, by which the sector can be judged according to the rotating argument of voltage space vector, and the function time of basic voltage vector can be calculated based on the three-phase voltage difference computation.Compared with the former two methods, the coordinate transformation and trigonometric calculation are completely omitted and the algorithm steps are simpli-fied in the optimized SVPWM.The validity and practicability can be verified through the simulation of VOC system with MATLAB/SIMULINK, which provides the basis for the hardware design of the improved three-phase VSR.%介绍了三相电压型PWM整流器（VSR）的拓扑结构和电压定向控制（VOC）的基本原理。针对三相VSR传统中电压空间矢量（ SVPWM）算法的缺陷性，提出了一种优化SVPWM调制方法。该方法利用电压空间矢量旋转的幅角来判断扇区，并由相电压的电压差值计算基本电压矢量的作用时间，完全省略了坐标变换和三角函数计算，化简了SVPWM算法步骤。经过MATLAB／SIMULINK建立电压定向控制（ VOC）仿真模型，可以证明该优化SVPWM算法的正确性，为改进三相VSR的硬件设计提供了依据。
The General Technique of Selected Harmonics Elimination for Multilevel Converters
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
For high power applications, multilevel converters have many advantages in comparison with other circuit topologies with output transformers. Cascaded inverters are one type of multilevel converters, they are easy to implement, very suitable for modularized layout and packaging. Their manufacturing cost is low. A multilevel PWM technique, called as General Technique of Selected Harmonics Elimination(GTSHE), is proposed in the paper. A general harmonic elimination equation for N cells, M pulses per half cycle, nth harmonic is derived, and verified by simulation results.
Pulsewidth Modulation of Neutral-Point-Clamped Indirect Matrix Converter
DEFF Research Database (Denmark)
Blaabjerg, Frede; Poh Chiang, Loh; Gao, Feng
2008-01-01
discussed in the existing literature. Addressing the previously described issues, this paper focuses on the operational mode analysis of a three-level indirect matrix converter implemented using a neutral-point-clamped inversion stage and the design of a number of PWM and modulation ratio compensation...... schemes for controlling the converter with improved waveform quality. The performances and practicalities of the designed schemes are verified in simulation and experimentally using an implemented laboratory prototype with some representative results captured and presented in this paper....
Robust DC/DC converter control for polymer electrolyte membrane fuel cell application
Wang, Ya-Xiong; Yu, Duck-Hyun; Chen, Shi-An; Kim, Young-Bae
2014-09-01
This study investigates a robust controller in regulating the pulse width modulation (PWM) of a DC/DC converter for a polymer electrolyte membrane fuel cell (PEMFC) application. A significant variation in the output voltage of a PEMFC depends on the power requirement and prevents a PEMFC from directly connecting to a subsequent power bus. DC/DC converters are utilized to step-up or step-down voltage to match the subsequent power bus voltage. In this study, a full dynamic model, which includes a PEMFC and boost and buck DC/DC converters, is developed under MATLAB/Simulink environment for control. A robust PWM duty ratio control for the converters is designed using time delay control (TDC). This control enables state variables to accurately follow the dynamics of a reference model using time-delayed information of plant input and output information within a few sampling periods. To prove the superiority of the TDC performance, traditional proportional-integral control (PIC) and model predictive control (MPC) are designed and implemented, and the simulation results are compared. The efficacies of TDC for the PEMFC-fed PWM DC/DC converters are validated through experimental test results using a 100 W PEMFC as well as boost and buck DC/DC converters.
"Assessment of Potentially-Efficient DC-AC Converter Architectures"
Energy Technology Data Exchange (ETDEWEB)
Chapman, Jamie
2004-04-29
Two alternate and potentially-efficient power electronic architectures are assessed and compared with a conventional, three-phase, voltage-source converter. The comparisons are in terms of a 750 kVA converter as might be used with a variable-speed wind turbine or a photovoltaic array, The two architectures are projected to cost 1.15 and 1.39 times the comparable (factory) cost of the conventional system. However the present value of the recovered energy stream may justify the added cost.
"Assessment of Potentially-Efficient DC-AC Converter Architectures"
Energy Technology Data Exchange (ETDEWEB)
Chapman, Jamie
2004-04-29
Two alternate and potentially-efficient power electronic architectures are assessed and compared with a conventional, three-phase, voltage-source converter. The comparisons are in terms of a 750 kVA converter as might be used with a variable-speed wind turbine or a photovoltaic array, The two architectures are projected to cost 1.15 and 1.39 times the comparable (factory) cost of the conventional system. However the present value of the recovered energy stream may justify the added cost.
Modular Multi-level converter based HVDC System for Grid Connection of Offshore Wind Power Plant
DEFF Research Database (Denmark)
Gnanarathna, U.N.; Chaudhary, Sanjay Kumar; Gole, A.M.;
2010-01-01
This paper explores the application of modular multi-level converters (MMC) as a means for harnessing the power from off-shore wind power plants. The MMC consists of a large number of simple voltage sourced converter (VSC) submodules that can be easily assembled into a converter for high......-voltage and high power. The paper shows that the MMC converter has a fast response and low harmonic content in comparison with a two-level VSC option. The paper discusses the modeling approach used, including a solution to the modeling challenge imposed by the very large number of switching devices in the MMC....
Pengaruh Penambahan PWM (Pulse Width Modulation Pada Generator HHO Tipe Dry Cell
Directory of Open Access Journals (Sweden)
Fungky Dyan Pertiwi
2013-09-01
Full Text Available Generator HHO memanfaatkan proses elektrolisis air agar mendapatkan gas H2. Namun, pada praktiknya pemakaian arus dari aki yang besar dan temperatur tinggi membuat bejana generator menjadi cepat rusak, sehingga dibutuhkan tambahan rangkaian elektronika PWM pada pengujian generator HHO guna mengatasi permasalahan tersebut. Penelitian menggunakan elektroda plat berjumlah 9 berdimensi 120mm 120mm, tebal 1mm dan dibatasi oleh o-ring dengan diameter 126mm, tebal 3mm. Pengujian dilakukan secara eksperimen dengan 2 kelompok yaitu kelompok control yang mana pengujian tanpa menggunakan PWM serta kelompok uji dimana pengujian menggunakan PWM dengan variasi duty cycle 30%, 50% dan 70%. Pengujian dilakukan hingga temperatur elektrolit 93oC. Hasil uji didapatkan bahwa arus, laju produksi dan efisiensi terbesar didapatkan pada pengujian tanpa PWM yang mencapai 60,6A, 6,033 10-6kg/s dan 25,69%. Namun, pada pengambilan data kedua efisiensi turun menjadi 19,74%. Penambahan PWM pada pengujian berpengaruh pada arus dan temperatur yang stabil meskipun laju produksi dan efisiensi lebih kecil daripada pengujian tanpa PWM. Pengujian dengan PWM pada duty cycle 70% menghasilkan laju produksi dan efisiensi terbesar yang mencapai 1,843 10-6 kg/s dan 15,19%.
Novel Full-bridge ZVS DC-DC Converter with an Clamp Diodes
Guangqun, Nan; Xue, Hu
The two arms of this converter all work at zero-voltage switching condition, that bring many advantages, such as little loss of power, simple control, etc. But these also exists some problems, such as parasitic oscillation on the output rectifier diodes. A novel full-bridge ZVS PWM DC-DC converter which adopts two clamping diodes in the first side of the transformer is proposed to reduce the parasitic oscillation in this paper. In this paper, It heavily analyzes the realization process of their soft-switching and the reason of related issues and solution, we establishes simulation model and simulates using orCAD. Finally,a 5 kW ZVS PWM DC-DC converter Prototype in that TMS320F2812 is the core controlled chip has been set up, and the experiments showed us the validation of the correlative theory.
A study of DC-DC converters with MCT's for arcjet power supplies
Stuart, Thomas A.
1994-01-01
Many arcjet DC power supplies use PWM full bridge converters with large arrays of parallel FET's. This report investigates an alternative supply using a variable frequency series resonant converter with small arrays of parallel MCT's (metal oxide semiconductor controlled thyristors). The reasons for this approach are to: increase reliability by reducing the number of switching devices; and decrease the surface mounting area of the switching arrays. The variable frequency series resonant approach is used because the relatively slow switching speed of the MCT precludes the use of PWM. The 10 kW converter operated satisfactorily with an efficiency of over 91 percent. Test results indicate this efficiency could be increased further by additional optimization of the series resonant inductor.
DEFF Research Database (Denmark)
Sharma, Ranjan; Rasmussen, Tonny Wederberg; Jensen, Kim Høj;
2010-01-01
power transmission options with HVDC systems are under consideration. In this paper, a comparison between a conventional HVAC transmission system and a HVDC system equipped with modular voltage source converters is provided. The comparison is based on the total energy transmission capability...
Parallel Interleaved VSCs: Influence of the PWM Scheme on the Design of the Coupled Inductor
DEFF Research Database (Denmark)
Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Maheshwari, Ram Krishan;
2014-01-01
-linkage in the CI is presented in this paper. The maximum flux density and the core losses, being the most important parameters for the CI design, are evaluated for continuous PWM and discontinuous pulsewidth modulation (DPWM) schemes. The effect of these PWM schemes on the design of the CI is discussed....... To limit the circulating current, magnetic coupling between the interleaved legs of the corresponding phase is provided by means of a Coupled Inductor (CI). The design of the CI is strongly influenced by the Pulsewidth Modulation (PWM) scheme used. The analytical model to evaluate the flux...
Architecture for a High-to-Medium-Voltage Power Converter
Vorpenian, Vatche
2008-01-01
A power converter now undergoing development is required to operate at a DC input potential ranging between 5.5 and 10 kV and a DC output potential of 400 V at a current up to 25 A. This power converter is also required to be sufficiently compact and reliable to fit and operate within the confines of a high-pressure case to be lowered to several miles (approx.5 km) below the surface of the ocean. The architecture chosen to satisfy these requirements calls for a series/ parallel arrangement of 48 high-frequency, pulse-width-modulation (PWM), transformer-isolation DC-to-DC power converter blocks. The input sides of the converter blocks would be connected in series so that the input potential would be divided among them, each of them being exposed to an input potential of no more than 10 kV/48 . 210 V. The series connection of inputs would also enforce a requirement that all the converter blocks operate at the same input current. The outputs of the converter blocks would be connected in a matrix comprising 6 parallel legs, each leg being a cascade of eight outputs wired in series (see figure). All the converter blocks would be identical within the tolerances of the values of their components. A single voltage feedback loop would regulate the output potential. All the converter blocks would be driven by the same PWM waveform generated by this feedback loop. The power transformer of each converter block would have a unity turns ratio and would be capable of withstanding as much as 10 kVDC between its primary and secondary windings. (Although, in general, the turns ratio could be different from unity, the simplest construction for minimizing leakage and maximizing breakdown voltage is attained at a turns ratio of unity.)
Stator insulation systems for medium voltage PWM drives fed motors
Energy Technology Data Exchange (ETDEWEB)
Gao, G.; Chen, W. [TECO-Westinghouse Motor Co., Round Rock, TX (United States)
2005-07-01
Adjustable speed drives (ASD) are commonly used in power electronics and control systems. It is estimated that more than 15 per cent of medium voltage motors are currently fed by such drives worldwide. A research project was conducted to examine the influence of medium voltage pulse width modulated (PWM) ASD on motor stator insulation systems. The findings, based on accelerated laboratory tests, have helped designers to improve the capabilities of the insulation system used for ASD-fed motors. Repetitive, high magnitude voltage spikes with fast rise time create significant stress on insulation systems. Gradual deterioration and premature failure of the motor insulation can result from surge voltages which generate surface discharges between phase windings/end windings, or partial discharges between stator turns. However, there is no industrial standard to evaluate motor insulation life under ASD-cable-motor conditions. Several material manufacturers have developed their own version of corona resistant material. However, the insulation life of ASD-fed motors does not depend solely on the raw materials. Rather, it depends on the complete insulation system, including the stator manufacturing process. In order to address this problem, TECO-Westinghouse Motor Company has developed special design criteria and manufacturing practices in order to reduce winding insulation temperature and to compensate for the additional heat generated by high frequency contents in the PWM voltage waveform. A patent pending new cooling system should reduce winding temperature by 15 to 20 degrees C. This paper presented design considerations for turn insulation, groundwall insulation, and a voltage stress grading system. A new thermal class H insulation system was also described. 6 refs., 2 tabs., 5 figs.
A Dual-Mode Step-up DC/DC Converter IC with Current-Limiting and EMI Reduction Techniques
Institute of Scientific and Technical Information of China (English)
Wan-Rone Liou; Chun-Ting Kuo; Mei-Ling Yeh; Ping-Hsing Chen; Marynelle L. Z. Rosales
2008-01-01
This paper presents a novel dual-modestep-up (boost) DC/DC converter. Pulse-frequencymodulation (PFM) is used to improve the efficiency atlight load. This converter can operate betweenpulse-width modulation (PWM) and pulse-frequencymodulation. The converter will operate in PFM mode atlight load and in PWM mode at heavy load. Themaximum conversion efficiency of this converter is 96%.The conversion efficiency is greatly improved when loadcurrent is below 100 mA. Additionally, a soft-startcircuit and a variable-sawtooth frequency circuit areproposed in this paper. The former is used to avoid thelarge switching current at the start up of the converterand the latter is utilized to reduce the EMI of theconverter.
a microprocessor-based control, scheme for a pwm voltage-fed ...
African Journals Online (AJOL)
Dr Obe
Department of Electrical Engineering ... integral controllers constitute the main control program while the application of thyristor gating ... PWM strategies depend on application .... Figure 3(a) shows the basic principle of gating signal.
PWM Switching Frequency Effects on Eddy Current Sensors for Magnetically Suspended Flywheel Systems
Jansen, Ralph; Lebron, Ramon; Dever, Timothy P.; Birchenough, Arthur G.
2003-01-01
A flywheel magnetic bearing (MB) pulse width modulated power amplifier (PWM) configuration is selected to minimize noise generated by the PWMs in the flywheel position sensor system. Two types of noise are addressed: beat frequency noise caused by variations in PWM switching frequencies, and demodulation noise caused by demodulation of high order harmonics of the switching voltage into the MB control band. Beat frequency noise is eliminated by synchronizing the PWM switch frequencies, and demodulation noise is minimized by selection of a switching frequency which does not have harmonics at the carrier frequency of the sensor. The recommended MB PWM system has five synchronized PWMs switching at a non-integer harmonic of the sensor carrier.
Directory of Open Access Journals (Sweden)
O. Malik
2013-02-01
The internal PWM signal conversion occurs by the use of non-equilibrium physical processes in the semiconductor substrate of the MOS-C. The 10-20 V amplitude limited square PWM output signal is obtained by the amplification of the sensor signal with a standard 60 dB transimpedance amplifier. The amplified output signal presents positive and negative PWM waveforms that can be easily separated using diodes. The duty of the positive part is proportional to the light intensity, whereas the negative part is inversely proportional to the intensity. The frequency operating range of this proposed instrument varies from 1 Hz to a few kilohertz. The duty cycle of the PWM output signal varies from 2% to 98% when the incident light intensity varies in the microwatts range. These new transducers or sensors could be useful for automatic control, robotic applications, dimmer systems, feedback electronic systems, and non-contact optical position sensing for nulling and centering measurements.
Design of a High Performance Green-Mode PWM Controller IC with Smart Sensing Protection Circuits
National Research Council Canada - National Science Library
Shen-Li Chen; Shih-Hua Hsu
2014-01-01
A design of high performance green-mode pulse-width-modulation (PWM) controller IC with smart sensing protection circuits for the application of lithium-ion battery charger is investigated in this article...
Energy Technology Data Exchange (ETDEWEB)
Silva Junior, Pedro A. da; Selinke, Rubens A.; Martins, Denizar Cruz [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Engenharia Eletrica. Inst. de Eletronica de Potencia
1996-12-31
This paper presents the analysis and implementation of an algorithm for numerical simulation applied to static converter, using PWM modulation and PID (Proportional Integral Derivative) controller. A buck converter prototype is designed and the experimental results are compared to those of the simulation. (author) 5 refs., 7 figs.; e-mail: inep at inep.ufsc.br
Analysis of VCO based noise shaping ADCs linearized by PWM modulation
Hernandez, Luis; Prefasi, , Enrique; Paton , Susana; Rombouts, Pieter
2012-01-01
Nonlinearity is one of the main problems associated with VCO based noise shaping ADCs. Their open loop architecture does not permit correction of the nonlinear voltage to frequency response of the VCO by feedback. Recently, linearization of a VCO ADC by Pulse Width Modulation (PWM) precoding has been proposed. Here, the input signal is encoded by a PWM modulator to drive the VCO with a 2-level signal, thus eliminating the nonlinearity of the VCO. This paper analyzes the remaining inherent dis...
Positioning Error of Optoelectronic Telescope Compensated by Bipolar PWM Driving Mode
Institute of Scientific and Technical Information of China (English)
LI Xiao-yan; ZHOU Hui; FU Hong; HOU Yun-hai
2005-01-01
The optoelectronic telescope has two sets of control systems: azimuth one and elevation one, and both are driven by PWM power amplifier with high efficiency and wide speed regulation range. The diagram of the azimuth control system is demonstrated, the nonlinear factors is analyzed at low speed, and some related experiments are carried out. The results show that the positioning error with unipolar is 86 codes(106.21″),while 18 codes (22. 23″) is with bipolar PWM driver.
A New Method for Maintaining Constant Dither Amplitude in Low Frequency PWM
Directory of Open Access Journals (Sweden)
KANG, H.
2017-02-01
Full Text Available Various controls for fluid flow and pressure are now required in related industries, and the pulse width modulation (PWM and dithering techniques have become essential for the proportional control of solenoids. However, there is a fatal drawback when the dither current signals are generated as a by-product of low frequency PWM. That is, the average current and the dither amplitude in low frequency PWM cannot be controlled independently. Therefore, a new method for maintaining constant dither amplitudes is proposed in this paper. Throughout the mathematical analysis, the effect of PWM frequency and duty cycle on the average current and dither amplitude was investigated, and the analysis result was validated by electrical experiments. Based on the mathematical analysis, a new method that properly varies both the duty cycle and the PWM frequency to obtain the desired average current and constant dither amplitude was established and verified. This method requires only the calculations for determining the proper PWM frequency and duty cycle, so it is possible to improve the performance of a proportional solenoid valve without additional devices or cost.
Indian Academy of Sciences (India)
A Ramachandran; M Channa Reddy; Ranjan Moodithaya
2008-10-01
The recent increase in the use of speed control of ac induction motor for variable speed drive using pulse width modulation (PWM) inverter is due to the advent of modern power electronic devices and introduction of microprocessors. There are many advantages of using ac induction motor for speed control applicatons in process and aerospace industries, but due to fast switching of the modern power electronic devices, the parasitic coupling produces undesirable effects. The undesirable effects include radiated and conducted electromagnetic interference (EMI) which adversely affect nearby computers, electronic/electrical instruments and give rise to the ﬂow of bearing current in the induction motor. Due to the ﬂow of bearing current in the induction motor, electrical discharge machining takes place in the inner race of the bearing which reduces the life of the bearing. In high power converters and inverters, the conducted and radiated emissions become a major concern. In this paper, identiﬁcation of bearing current due to conducted emission, the measurement of bearing current in a modiﬁed induction motor and to minimize the bearing current are discussed. The standard current probe, the standard line impedance stabilization network (LISN)), the electronics interface circuits are used to measure high frequency common mode current, bearing current and to minimize the conducted noise from the system. The LISN will prevent the EMI noise entering the system from the supply source by conductive methods, at the same time prevents the EMI generated if any due to PWM, fast switching in the system, will not be allowed to enter the supply line. For comparing the results with Federal Communications Commission (FCC) and Special Committee on Radio Interference (CISPR) standards, the graphs are plotted with frequency Vs, line voltage in $dB{_\\mu} V$, common mode voltage in $dB{_\\mu} V$ and the bearing current in $dB_{\\mu} A$ with out and with minimizing circuits.
Design of high performance voltage source with low voltage CMOS bandgap%一种高性能的低压CMOS带隙基准电压源的设计
Institute of Scientific and Technical Information of China (English)
安胜彪; 侯洁; 魏月婷; 陈书旺; 文环明
2012-01-01
提出一种新型的芯片内基准电压源的设计方案,基准电压源是当代数模混合集成电路以及射频集成电路中极为重要的组成部分.为满足大规模低压CMOS集成电路中高精度比较器、数模转换器、高灵敏RF等电路对基准电压源的苛刻需要,芯片内部基准电压源大部分采用基准带隙电压源.研究并设计了一种低功耗、超低温度系数和较高的电源抑制比的高性能低压CMOS带隙基准电压源.其综合了一级温度补偿、电流反馈技术、偏置电路温度补偿技术、RC相位裕度补偿技术.该电路采用台积电(TSMC)0.18 μm工艺,并利用Specture进行仿真,仿真结果表明了该设计方案的合理性以及可行性,适用于在低电压下电源抑制比较高的低功耗领域应用.%This article proposed a new design of a chip benchmark power sourse, which is a very important component of mixed signal IC and RF integrated circuit. To meet the requirement of low voltage and large-scale integrated CMOS circuit of high-precision, the use of reference source is rigors for A/D and D/A converter, high sensitive RF circuits and so on. Most parts of the benchmark source employ benchmark bandgap voltage source on chip, so a low power consumption, low temperature coefficient and high performance low pressure CMOS bandgap benchmark voltage source with higher PSRR is designed. It uses one level temperature compensation, current feedback technology, offset circuit temperature compensation technology and RC phase margin compensation technology. This circuit adopts the 0. 18 urn process of TSMC, and uses the Specture to simulate. The simulation result verifies the feasibility and rationality of the design. The circuit can be uesd for low voltage and tow power consumption with higher PSRR.
Compherensive Design of a 100 kW/400 V High Performance AC-DC Converter
2015-01-01
In this paper, a comprehensive design for a 100kW/400V, three-phase pulse-width modulated (PWM) AC-DC converter is presented that serves as the front-end power supply for wide-range varying active load. This power supply includes two series stages; a six-switch AC-DC boost converter and a DC-DC buck converter to regulate 400VDC at load side. The design of all inductors and capacitors is fulfilled using mathematical expressions. In addition, small signal modelling and controller design are pre...
DEFF Research Database (Denmark)
Kloch, Allan; Hansen, Peter Bukhave; Wolfson, David;
1999-01-01
at 2.5 Gbit/s, the regeneration causes a reduction of the required input power to an in-line EDFA of ~6 dB for a power penalty of 1 dB at a bit error rate of 10-9. If two converters are concatenated the power requirement is reduced ~8 dB. Obviously, the power reduction allows for longer spans between....... It is predicted that jitter accumulation can be minimised by using a 9-10 dB ratio between the signal and CW power also assuring a high extinction ratio. Using this guideline simulations show that 20 cross-gain modulation converters can be cascaded at 10 Gbit/s with only ~20 ps of accumulated jitter...... and an extinction ratio of ~10 dB.The regenerative capabilities of the cross-phase converters are described and verified experimentally at 20 Gbit/s, where the noise redistribution and improvement of the signal-to-noise ratio clearly is demonstrated by controlling the input power to an EDFA. In a similar experiment...
Institute of Scientific and Technical Information of China (English)
毛惠丰; 孔德鹏; 陈增禄; 杨旭; 王兆安
2015-01-01
提出了一种单相 H 桥电压型逆变器三电平滞环电流跟踪控制方法。该控制方法具有载波移相PWM调制效果以及无死区效应的特点。在稳态条件下，误差电流被严格限制在内环中。当指令电流发生突变并且达到外环的上或下阈值时，逆变器输出最高或最低电平以使误差电流以最快速度趋近于0。与传统的三电平滞环电流控制方法相比，该控制方法能进一步改善逆变器输出电流的波形。通过仿真和实验结果验证了该方法的有效性。%ABSTRACT:A new three-level hysteresis current controller for single-phase H-bridge voltage source inverters (VSI) is proposed here. The proposed hysteresis current controller has successfully combined the advantage of the symmetrical unipolar carrier-based PWM and no dead-time effects. Under steady-state conditions, the current error will be confined within the inner band. When the commanded current step changes so that the current error exceeds the outer hysteresis band, the extreme voltage level is selected to force the current error towards zero quickly. Compared with the conventional three-level hysteresis current controller, the proposed hysteresis current controlled single-phase H-bridge voltage source inverters can further improve the inverter output current waveform. Simulated and experimental results have been given to demonstrate the validity and features of the novel hysteresis current controller with the improved switching scheme.
Hybrid Voltage-Multipliers Based Switching Power Converters
Rosas-Caro, Julio C.; Mayo-Maldonado, Jonathan C.; Vazquez-Bautista, Rene Fabian; Valderrabano-Gonzalez, Antonio; Salas-Cabrera, Ruben; Valdez-Resendiz, Jesus Elias
2011-08-01
This work presents a derivation of PWM DC-DC hybrid converters by combining traditional converters with the Cockcroft-Walton voltage multiplier, the voltage multiplier of each converter is driven with the same transistor of the basic topology; this fact makes the structure of the new converters very simple and provides high-voltage gain. The traditional topologies discussed are the boost, buck-boost, Cuk and SEPIC. They main features of the discussed family are: (i) high-voltage gain without using extreme duty cycles or transformers, which allow high switching frequency and (ii) low voltage stress in switching devices, along with modular structures, and more output levels can be added without modifying the main circuit, which is highly desirable in some applications such as renewable energy generation systems. It is shown how a multiplier converter can become a generalized topology and how some of the traditional converters and several state-of-the-art converters can be derived from the generalized topologies and vice-versa. All the discussed converters were simulated, additionally experimental results are provided with an interleaved multiplier converter.
OW式永磁直驱风电系统不连续脉宽调制∗%Open Winding PMSG for Discontinuous PWM
Institute of Scientific and Technical Information of China (English)
殷杰; 向铁元; 杨瑶
2015-01-01
Permanent Magnet Synchronous Generator current ripple in the operation proposed an open winding type permanent magnet direct drive wind power system for discontinuous PWM modulation. Open winding pair was established equivalent switch model PMSG inverter drive system, clarify the decoupled nature of PWM modulation current ripple causes by introducing a“valid” by properly offset voltage vector time effectively solved PMSG machine side of the stator current ripple, realized the optimization of PMSG were converters power quality improvement. Finally, 110kW wind drag and experimental platform for the open winding PMSG continuous PWM modulation method for performance verification, verified the validity of the method in the optimization of PMSG on-grid power quality.%针对中压永磁直驱风电系统( PMSG)运行中存在的电流脉动问题，提出一种OW式永磁直驱风电系统不连续PWM调制方法。建立了OW双逆变器PMSG驱动系统等效开关模型，阐明了解耦PWM调制电流脉动问题的本质原因，引入“有效时间”概念，通过合理地偏移有效电压矢量作用时间，解决了PMSG机侧定子电流脉动问题，实现了PMSG变流器发电品质的优化提高。最后，基于110 kW风力发电对拖试验平台对所提OW PMSG不连续PWM调制方法进行性能验证，验证了该方法对优化PMSG并网电能品质的有效性。
Analysis of Single Phase PWM Rectifier for Different Applications
Mitra, Arkendu; Chowdhuri, Sumana
2017-04-01
This research work investigates the various applications of a PWM rectifier based on its input power factor. Most of the cases, the papers describe the operation of the rectifier used for unity power factor (UPF) operation. Beside this mode of operation, this paper compiles the application of the rectifier as STATCOM also, where the rectifier deals only with reactive power exchange. In this work, the controller is implemented by inserting a loop for reference input of phase angle which will be compared with the actual one, so that user can operate the rectifier at any power factor. Some basic formulae are derived for the input current, active power and reactive power based on which the control circuit is to be designed. Here two Proportional-Integral (PI) controllers are used. A brief description of tuning these two PI controllers is incorporated in this paper. Also some calculations are given to determine the harmonic factors of the input line current from which it is found that the rectifier when operated in each mode operation, the order of the harmonics are very low.
Analysis of Single Phase PWM Rectifier for Different Applications
Mitra, Arkendu; Chowdhuri, Sumana
2016-06-01
This research work investigates the various applications of a PWM rectifier based on its input power factor. Most of the cases, the papers describe the operation of the rectifier used for unity power factor (UPF) operation. Beside this mode of operation, this paper compiles the application of the rectifier as STATCOM also, where the rectifier deals only with reactive power exchange. In this work, the controller is implemented by inserting a loop for reference input of phase angle which will be compared with the actual one, so that user can operate the rectifier at any power factor. Some basic formulae are derived for the input current, active power and reactive power based on which the control circuit is to be designed. Here two Proportional-Integral (PI) controllers are used. A brief description of tuning these two PI controllers is incorporated in this paper. Also some calculations are given to determine the harmonic factors of the input line current from which it is found that the rectifier when operated in each mode operation, the order of the harmonics are very low.
Institute of Scientific and Technical Information of China (English)
张伟龙; 谢新胜; 李帅
2013-01-01
With the continuous development of power electronics technology and mature, As the importance of power electronics technology and simulation applications. PWM and SPWM technology and PSIM software will certainly be with the power electronics technology development is recognized by more and more people. This paper simply introduces the technology of the most basic concepts, with PSIM software to deepen the understanding of them, Let us in the future life and work have a basic understanding of and cognition, also make a foundation for future learning.%随着电力电子技术的不断发展与成熟，电力电子在各个方面都得到了广泛的应用。而作为电力电子技术的重要技术和仿真应用软件，PWM与SPWM技术及PSIM软件必然会随着电力电子技术的发展被越来越多的人所认识。本文通过简单地介绍这项技术的最基本概念，并用PSIM软件来加深对它们的理解，让大家在日后的生活和工作有一个基本的了解和认识，也为今后的学习打一个基础。
PWM-Statcom system additionally having active filter function
Energy Technology Data Exchange (ETDEWEB)
Matsui, K.; Kojima, H.; Yamamoto, I.; Hasegawa, M. [Chubu Univ., Kasugai Aichi (Japan); Ando, K. [Nitto Kogyo Corp., Nagakute, Aichi (Japan)
2006-07-01
The harmonic characteristics of static synchronous compensators (Statcom) were discussed with particular reference to the difference between symmetrical and asymmetrical modulation strategies that influence a quality of output waveform. The asymmetrical modulation strategy is the better approach in higher power factor applications such as alternating current (AC) motor drives. It was noted that in cases requiring a passive filter with a very large scale Statcom, a symmetrical modulation strategy is superior. Therefore, in this study, a symmetrical modulation was preferred for a neutral point clamped (NPC) pulse width modulation (PWM) inverter. Due to switching in a limited narrow frequency band, such output harmonics can be eliminated using a simple passive filter and harmonics such as the fifth and the seventh, can be suppressed using the proposed Statcom scheme in which the feedback signals for the fifth and seventh harmonics are injected into the Statcom. Using these feedback signals, the harmonics in the power system were significantly reduced. This result was also confirmed by simulation. It was concluded that, in addition to the proper operation of the Statcom, it is possible to perform an active filtering function . 10 refs., 1 tab., 9 figs.
Distributed Generation using Indirect Matrix Converter in Boost Operating Mode
DEFF Research Database (Denmark)
Liu, Xiong; Loh, Poh Chiang; Wang, Peng
2011-01-01
, reverse power flow operation of IMC can be implemented to meet voltage boost requirement, where the input ac source is connected to the converter's voltage source side and the output utility grid or load is connected to the current source side. This paper proposes control schemes of IMC under reverse...... power flow operation for both grid-connected and isolated modes with distributed generation suggested as a potential application. In grid-connected mode, the commanded power must be extracted from the input ac source to the grid, in addition to guarantee sinusoidal input/output waveforms, unity input...
Distributed Generation using Indirect Matrix Converter in Boost Operating Mode
DEFF Research Database (Denmark)
Liu, Xiong; Loh, Poh Chiang; Wang, Peng
2011-01-01
, reverse power flow operation of IMC can be implemented to meet voltage boost requirement, where the input ac source is connected to the converter's voltage source side and the output utility grid or load is connected to the current source side. This paper proposes control schemes of IMC under reverse...... power flow operation for both grid-connected and isolated modes with distributed generation suggested as a potential application. In grid-connected mode, the commanded power must be extracted from the input ac source to the grid, in addition to guarantee sinusoidal input/output waveforms, unity input...
Comparison of three different Modulators for Power Converters with Respect to EMI Optimization
DEFF Research Database (Denmark)
Knott, Arnold; Pfaffinger, Gerhard; Andersen, Michael Andreas E.
2008-01-01
Switch-mode Power Converters are well known for emissions in the band of electromagnetic interference (EMI) interest. The spectrum shape depends on the type of modulator and its purpose. This paper gives design guidelines to choose the optimum topology depending on requirements of different...... applications. Spectral measurements on prototypes of a pulse width modulator (PWM), a -modulator and a hysteretic self-oscillating modulator are shown, which are verifying their simulations, with respect to different EMI challenges....
Design of benchmark voltage source based on single N-type process%基于N型工艺的基准电压源设计
Institute of Scientific and Technical Information of China (English)
李仲秋
2011-01-01
A kind of generating benchmark voltage circuit is designed integrating with only n-type active device and passive components process by using op-amp of the feedback closed-loop control method to generate benchmark voltage based on the traditional complementary type bandgap benchmark voltage source in only n-type active device technology.It provides a good power supply rejection ratio characteristics and the benchmark voltage source circuit of effectively compensating the negative temperature coefficient on n-type device pressure drop changes for only existing n-type MOS or NPN transistor,no P type device,difficultly using conventional bandgap voltage source structure to produt specific technology of accurate reference voltage,and the measures to improve the feedback loop stability are put forward.%针对传统互补型带隙基准电压源在只有N型有源器件工艺中的局限性,采用运放反馈的闭环控制方法来产生基准电压,设计了一种可以集成于只有N型有源器件和无源元件工艺中的基准电压源产生电路。为只存在N型MOS或者NPN型晶体管、没有P型器件、难以用传统的带隙电压源结构来产生精确参考电压的特定工艺,提供了一种具有良好的电源抑制比特性和有效地补偿N型器件结压降变化的负温度系数的基准电压源电路;并提出了提高反馈回路稳定性的措施。
Analysis of Symmetrical Pulse Width Modulation Strategies for Matrix Converters
DEFF Research Database (Denmark)
Larsen, K.B.; Jorgensen, A.H.; Helle, Lars
2002-01-01
This paper presents a new and easy way to understand the derivation of the modulation functions for matrix converters. It is shown how the duty cycles can be calculated using techniques known from the back-to-back (B2B) voltage source inverter (VSI), thus making the subject accessible to people...... with prior knowledge in standard drives. A new modulation strategy is presented minimizing harmonic distortion compared to the standard double-sided space vector modulation for matrix converters. An improvement to an existing modulator is also presented where the proposed modification improves the harmonic...... performance. The strategies are compared both analytically and by the use of both simulations and measurements on a 12 kW matrix converter prototype.It is found that the proposed modulator has superior performance compared to modulators with equal switching frequencies and an equal number of switchings....
DEFF Research Database (Denmark)
Busquets-Monge, S.; Maheshwari, Ram Krishan; Munk-Nielsen, Stig
2013-01-01
This paper presents a novel PWM strategy for nlevel three-leg semiconductor-clamped dc-ac converters in the overmodulation region, with dc-link capacitor voltage balance in every switching cycle. The strategy is based on the virtual-vector concept. Suitable reference vector trajectories are selec...
Directory of Open Access Journals (Sweden)
Ufa Ruslan A.
2014-01-01
Full Text Available The motivation of the presented research is based on the needs for development of new methods and tools for adequate simulation of Flexible Alternating Current Transmission System (FACTS devices and High Voltage Direct Current Transmission (HVDC system as part of real electric power systems (EPS. For that, a hybrid approach for advanced simulation of the FACTS and HVDC based on Voltage Source is proposed. The presented simulation results of the developed hybrid model of VSC confirm the achievement of the desired properties of the model and the effectiveness of the proposed solutions.
DEFF Research Database (Denmark)
Padmanaban, Sanjeevi Kumar; Hontz, Michael R.; Khanna, Raghav
2016-01-01
This article presents the developments of a novel isolated/non-isolated quad inverter configuration for multilevel dual six-phase (twelve-phase) star-winding converter. The modular circuit consists of four standard voltage source inverters (VSIs). Each VSI is incorporated with one bi-directional ...
Control and design of full-bridge three-level converter for renewable energy sources
DEFF Research Database (Denmark)
Yao, Zhilei; Xu, Jing; Guerrero, Josep M.
2015-01-01
Output voltage of renewable energy sources, such as fuel cell and PV cell, is often low and varies widely with load and environmental conditions. Therefore, the high step-up DC-DC converter is needed between renewable energy sources and the grid-connected inverter. However, voltage stress...... of rectifier diodes is high and filter is large in traditional voltage-source converters in a wide input-voltage range. In order to solve the aforementioned problems, a full-bridge (FB) three-level (TL) converter is proposed. It can operate at both two-level and three-level modes, so it is suitable for wide...... input-voltage range application. Compared with FB converter, voltage stress of rectifier diodes and the filter can be reduced. Operating principle and control strategy of the proposed converter are illustrated. Design guidelines and example are given. Simulation results of a 1-kW FB TL converter verify...
EVALUATION OF VARIOUS UNIPOLAR MULTICARRIER PWM STRATEGIES FOR FIVE LEVEL FLYING CAPACITOR INVERTER
Directory of Open Access Journals (Sweden)
B. SHANTHI
2012-06-01
Full Text Available This paper presents the comparison of unipolar multicarrier Pulse Width Modulation (PWM techniques for the Flying Capacitor Multi Level Inverter (FCMLI. Due to switch combination redundancies, there are certain degrees of freedom to generate the five level AC output voltage. This paper presents the use of Control Freedom Degree (CFD combination. The effectiveness of the PWM strategies developed using CFD are demonstrated by simulation and experimentation. The results indicate that the multilevel inverter triggered by the developed USHPWM strategy exhibits reduced harmonics. PWM strategies developed are implemented in real time using dSPACE/Real Time Interface (RTI. The simulation and experimental output closely match with each other validating the strategies presented.
Isolated PDM and PWM DC-AC SICAMs[Pulse Density Modulated; Pulse Width Modulated
Energy Technology Data Exchange (ETDEWEB)
Ljusev, P.
2004-03-15
In this report a class of isolated PDM and PWM DC-AC SICAMs is described, which introduce the audio reference only in the output stage. AC-DC power supply is implemented in its simplest form: diode rectifier followed by a medium-size charge-storage capacitor. Isolation from the AC mains is achieved using a high frequency (HF) transformer, receiving the HF voltage pulses from the input 'inverter' stage and transferring them to the output 'rectifier+inverter' stage, which can use either PDM or PWM. The latter stage is then interfaced to the load using an output low-pass filter. Each of the dedicated stages is discussed in detail. Measurements on the master/slave PWM DC-AC SICAM prototype are presented to help benchmarking the performance of this class of SICAMs and identify the advantages and drawbacks. (au)
A novel PWM scheme to eliminate the diode freewheeling In the Inactive phase in BLDC motor
Institute of Scientific and Technical Information of China (English)
WEI Kun; HU Chang-sheng; ZHANG Zhong-chao
2006-01-01
The brushless DC motor (BLDCM) with trapezoidal electromotive force (back-EMF) waveform is used widely.In principle,when the motor runs in the 120°conduction mode,two of the three phases are active while the other phase is inactive at all times.However,a ripple current occurs in the inactive phase due to the diode freewheeling during the non-commutation period in the traditional pulse width modulation (PWM) methods,which aggravates the torque ripples.A new PWM method is proposed in this paper to eliminate the diode freewheeling during the non-commutation period in the inactive phase.As a result,the torque ripple is suppressed using the proposed method.The simulation and experimental results are demonstrated to verify the validity of the proposed PWM method.
Design hardware calculator in PWM peripherals of nios Ⅱ with verilog HDL
Institute of Scientific and Technical Information of China (English)
XU Yang; XIANG Min
2009-01-01
The Plus Width Module (PWM) in microprocessors is commonly used in motor control field. If the ordinary PWM peripherals output PWM waveform, the software must calculate the period and duty cycle number based on the microprocessor's system clock cycle first, and then write them into the registers. As all known, the microprocessor without hardware calculator consume very long time in multiplication and division. In order to reduce the CPU's running time, a calculation hardware unit was designed to calculate the waveform parameters. The software only need to write the period (Hz units) to the period register and the duty cycle (% units)to its register. This hardware unit was designed with Verilog HDL and running in the Nios II system successfully.
A Back-to-Back 2L-3L Grid Integration of a Marine Current Energy Converter
Directory of Open Access Journals (Sweden)
Senad Apelfröjd
2015-01-01
Full Text Available The paper proposes a back-to-back 2L-3L grid connection topology for a marine current energy converter. A prototype marine current energy converter has been deployed by a research group at Uppsala University. The concept behind the prototype revolves around a fixed pitch vertical axis turbine directly connected to a permanent magnet synchronous generator (PMSG. The proposed grid connection system utilizes a well known and proven two level voltage source converter generator-side combined with a three-level cascaded H-bridge (CHB multilevel converter grid-side. The multilevel converter brings benefits in terms of efficiency, power quality and DC-link utilization. The system is here presented for a single marine current energy converter but can easily be scaled up for clusters of marine current energy converters. Control schemes for both grid-side and generator-side voltage source converters are presented. The start-up, steady state and dynamic performance of the marine current energy converter are investigated and simulation results are presented in this paper.
Energy Technology Data Exchange (ETDEWEB)
Abdoulin, E. [International Rectifier France, 91 - Saint Michel sur Orge (France)
2000-03-01
Power MOSFETs used as synchronous rectifiers in isolated DC to DC converters allow to design energy efficient power supplies. In order to improve the efficiency of the isolated DC-DC converter of about 5%, the synchronous controller rectifier designed by International Rectifier is based on a predictive method in order to generate the appropriate signals for the driving of the secondary stage MOSFETs. In addition, the PWM architecture of the primary stage is not modified. (J.S.)
高电源电压抑制比基准电压源的设计%Design of reference voltage source with high power supply rejection ratio
Institute of Scientific and Technical Information of China (English)
李承蓬; 许维胜; 王翠霞
2014-01-01
在此通过对带隙基准电压源电路进行建模分析，针对逆变电路的中低频使用环境，设计了一个应用于高压逆变器电路中的高电源电压抑制比，低温度系数的带隙基准电压源。该电路采用1μm，700 V高压CMOS工艺，在5 V供电电压的基础上，采用一阶温度补偿，并通过设计高开环增益共源共栅两级放大器来提高电源电压抑制比，同时使用宽幅镜像电流偏置解决因共源共栅引起的输出摆幅变小的问题。基准电压源正常输出电压为2.394 V，温度系数为8 ppm/℃，中低频电压抑制比均可达到-112 dB。%Based on modeling and analysis of the bandgap reference voltage source circuit,a bandgap reference voltage source with high power supply rejection ratio and low temperature coefficient was designed for high-voltage low-frequency inverter circuit. CMOS process of 1 μm and 700 V high-voltage is used in this circuit,which adopts first-order temperature compensa-tion at 5 V voltage. A cascode two-stage amplifier with high open-loop gain was designed to improve the power supply rejection ratio. The wide mirror current bias circuit is used to solve the problem that the output swing becomes smaller due to the cascode circuit. The normal output voltage of the reference voltage source is 2.394 V,its temperature coefficient is 8 ppm/℃,and its low-medium frequency voltage rejection ratio can reach -112 dB.
PV Power-Generation System with a Phase-Shift PWM Technique for High Step-Up Voltage Applications
Directory of Open Access Journals (Sweden)
Cheng-Tao Tsai
2012-01-01
Full Text Available A PV power-generation system with a phase-shift pulse-width modulation (PWM technique for high step-up voltage applications is proposed. The proposed power-generation system consists of two stages. In the input stage, all power switches of the full-bridge converter with phase-shift technique can be operated with zero-current switching (ZCS at turn-on or turn-off transition. Hence, the switching losses of the power switches can be reduced. Then, in the DC output stage, a voltage-doubler circuit is used to boost a high dc-link bus voltage. To supply a utility power, a dc/ac inverter is connected to induce a sinusoidal source. In order to draw a maximum power from PV arrays source, a microcontroller is incorporated with the perturbation and observation method to implement maximum power point tracking (MPPT algorithm and power regulating scheme. In this study, a full load power of 300 W prototype has been built. Experimental results are presented to verify the performance and feasibility of the proposed PV power-generation system.
HVDC Solution for Offshore Wind Park Comprising Turbines Equipped with Full-Range Converters
DEFF Research Database (Denmark)
Sharma, Ranjan; Rasmussen, Tonny Wederberg; Jensen, Kim Høj
2010-01-01
of a HVDC transmission system. The power system under study includes an offshore wind farm comprising turbines equipped with full range converters. The collection network is a local AC grid. Power transmission is done through HVDC system. The grid side VSC (voltage source converter) controls the DC voltage...... a voltage drop is created at the collection grid, the wind turbines go into fault-ride-through mode. The power output from each of the wind turbines is thus reduced to balance the system power. The detailed explanation of the strategy is presented in the paper. Matlab simulation model was prepared and some...
Dual PWM Wind Power Grid System Based on DSP%基于DSP双PWM风力发电并网系统的研究
Institute of Scientific and Technical Information of China (English)
吕振; 孟祥海; 林振杨; 高爽
2011-01-01
The double PWM wind power grid systems theory was analyzed. The basic theory of the wind power generator system was elaborated based on DSP TMS320LF2407, while the system machine-side converter and the network-side converter were analyzed. And by controlling the inverter output, the parallel running with the grid is realized under the premise of ensuring the quality of the output power. And to ensure that the harmonic content fed into the grid should be as small as possible while still meet the power requirements. Finally, the whole system was verified by experiment, experiment results show that the dual PWM wind power grid system has good stability and reliability.%详细分析了风力发电双PWM并网系统的原理,阐述了基于DSP TMS320LF2407风力发电并网系统的基本理论,同时对系统的机侧变流器和网侧变流器进行了分析,并通过控制逆变器的输出,在保证输出电能质量的前提下实现与电网的并行运行；并且保证馈入电网的谐波含量要尽可能小的同时还要符合功率要求.最后,对整个系统进行了实验验证,实验结果表明,双PWM风力发电并网系统具有良好的稳定性和可靠性.
A New Zero Voltage Switching Buck-Boost Type DC-DC Converter
Directory of Open Access Journals (Sweden)
Majid Delshad
2010-03-01
Full Text Available In this paper, a new zero voltage switching isolated buck-boost DC-DC converter with active clamp circuit is proposed. The active clamp circuit in this converter not only absorbs voltage spikes across the main switch but also provides soft switching conditions for all switches. All switches are PWM controlled which simplifies the control implementation. One of the main advantages of this converter is the that it operating can operate at high power levels while soft switching conditions exist in both buck and boost modes of converter operation. Since this converter can operate over a wide input voltage range, it can be employed in power factor correction. The experimental results obtained from a 150W prototype circuit operating at 100KHz are presented to confirm the integrity of the proposed circuit.
Directory of Open Access Journals (Sweden)
Fei Chang
2015-01-01
Full Text Available The modular multilevel converter (MMC is an emerging voltage source converter topology suitable for multiterminal high voltage direct current transmission based on modular multilevel converter (MMC-MTDC. This paper presents fault characteristics of MMC-MTDC including submodule fault, DC line fault, and fault ride-through of wind farm integration. Meanwhile, the corresponding protection strategies are proposed. The correctness and effectiveness of the control strategies are verified by establishing a three-terminal MMC-MTDC system under the PSCAD/EMTDC electromagnetic transient simulation environment.
Medium Voltage Three-level Converters for the Grid Connection of aMulti-MW Wind Turbine
DEFF Research Database (Denmark)
Senturk, Osman Selcuk; Helle, Lars; Munk-Nielsen, Stig
2009-01-01
Three-level (3L) neutral point clamped (NPC), flying capacitor (FC), and H-bridge (HB) voltage source converters (VSCs) as a grid-side full-scale medium voltage (MV) converter are modeled, controlled, and simulated for the grid connection of a hypothetical 6MW wind turbine. Via the converter...... connection circuit (without capacitive switching ripple filters), the 3L-HB-VSC is expected to be superior with respect to power density and reliability over the 3L-NPC- and -FC-VSCs....
Performance Evaluation of Split Output Converters with SiC MOSFETs and SiC Schottky Diodes
Yan, Qingzeng; Yuan, Xibo; Geng, Yiwen; Charalambous, Apollo; Wu, Xioajie
2017-01-01
The adoption of silicon carbide (SiC) MOSFETS and SiC Schottky diodes in power converters promises a further improvement of the attainable power density and system efficiency, while it is restricted by several issues caused by the ultra-fast switching, such as phase-leg shoot-through (‘crosstalk’ effect), high turn-on losses, electromagnetic interference (EMI), etc. This paper presents a split output converter which can overcome the limitations of the standard two-level voltage source convert...
DEFF Research Database (Denmark)
Xin, Zhen; Mattavelli, Paolo; Yao, WenLi
2017-01-01
Due to the low inductance of an LCL-filter, the grid current generated by an LCL-filtered Voltage Source Inverter (VSI) is sensitive to low-order grid-voltage harmonics. This issue is especially tough for the control system with Inverter Current Feedback (ICF), because the grid-current harmonics...... can freely flow into the filter capacitor without control. To cope with this issue, this paper develops an approach for the ICF control system to suppress the grid-current harmonics without adding extra sensors. The proposed method applies harmonic controllers and feedforward scheme simultaneously......, and the instability risk introduced by the feedforward loop can be ingeniously avoided through a special design of the feedforward position, which maintains the inherent stability characteristic of the ICF control system. The effectiveness of the proposed method and the correctness of the theoretical analyses...
Design and Control of Modular Multilevel Converter in an Active Front and Application
Asimakopoulos, Panagiotis; Prof Bongiorno, Massimo
2013-09-01
A proposed topology to operate as an Active Front End is the Modular Multilevel Converter. The Modular Multilevel Converter is a new solution in the field of medium and high power electronics. The converter's operation is based on the modular approach. It consists of modules, each one being a half-bridge connected in parallel to a capacitor. The special characteristic of this idea is that it is possible to build the sinusoidal waveform of the voltage by adding several modules in series in each phase-leg of the converter. An arm inductance is connected in series with the modules of every arm. In contrast to the two level voltage source converter, where the output phase voltage can be either plus or minus the half of the dc-link voltage, the MMC can change its output with steps equal to each module capacitor's voltage level.
Design and Implementation of Power Flow Control for a novel Dual Input DC-DC Converter
DEFF Research Database (Denmark)
Taeed, Fazel; Ouyang, Ziwei; Nymand, Morten
2014-01-01
In this paper a control strategy for controlling the power flow from input voltage sources of a novel dual-input dcdc converter to the load is introduced. The converter can be used in renewable energy applications with two independent power sources. Firstly, the operation principle of the converter...... to control the power flow in the converter. The implemented controller in FPGA is low cost and simple. The complete system can be practically used in power management for renewable energy sources....... is outlined; then the control method for adjusting power sharing is proposed. In the next step, the controller is implemented in an FPGA, and then a 350W dual input converter is built to verify operation of the proposed control strategy. The experimental results show the excellent ability of the controller...
EMC Specific Problems of Frequency Converters Used at Interlocking Device
Directory of Open Access Journals (Sweden)
J. Novak
2009-12-01
Full Text Available The paper deals with problems of electromagnetic compatibility (EMC of frequency control drive of electromotive switch actuator of railway switch. The frequency converter with Pulse Width Modulation (PWM and the output sinus filter are used for feeding of the asynchronous motor of the switch actuator. This drive is operated in an insulated system of feeding voltages. The drive is fed by a frequency converter with an unshielded cable with length up to 1.2 km. The EMC problems occurring at development and operating of the drive are analyzed in this paper. The used solution of these problems and experience with EMC of the given system from real operation are described in this paper as well.
Energy Technology Data Exchange (ETDEWEB)
Boehm, Christine
2015-01-14
Atomic masses and hence binding energies of nuclides are of great importance for studies of nuclear structure since they reflect all effective interactions in a nucleus. Within this thesis the masses of seven nuclides, namely {sup 194}Au, {sup 194}Hg, {sup 190,193,198}Tl and {sup 202,208}Pb, were determined at the Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN. The thallium region in the chart of isotopes is of special interest due to the occurrence of nuclear structure effects like low-lying isomers, level inversion, shape coexistence and deformations. These effects are investigated by applying finite-difference mass formulas, such as the two-neutron separation energies or the so-called empirical pairing gaps. The second topic addressed within the present thesis is an ultra-stable voltage source, called StaReP (Stable Reference for Penning Trap Experiments), which was developed at the Max-Planck-Institut fuer Kernphysik. It is one of the key components of the high-precision mass spectrometer PENTATRAP, containing a tower of five Penning traps. A 25-channel voltage source with a relative stability of few 10{sup -8} over a period of 10 minutes in the range of 0 to -100V is mandatory for PENTATRAP aiming for mass measurements with relative mass uncertainties of ≤ 10{sup -11}. Mass values with such a high precision allow for stringent tests of quantum electrodynamics in strong electric fields, testing Einstein's mass-energy relation E = mc{sup 2} as well as measurements of decay energies (Q-values) with applications in neutrino physics.
Energy Technology Data Exchange (ETDEWEB)
Garza Macias, Anibal [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)
1988-12-31
In the Mexico`s Gulf Coast and in the North East part of the country there are severe pollution problems on the electric distribution power systems insulators. To solve this problem, in specialized laboratories are reproduced the pollution conditions for their quantitative and qualitative analyses. In general terms, for this purpose special voltage transformers have been used that, for being imported, are very expensive; furthermore there is no defined selection criterion that allows the voltage source to supply the current recommended by the IEC (International Electrotechnical Commission). In this article, a proposal is presented to select a transformer that fulfills the IEC requirements. This equipment, because of its acquisition easiness and economy, permits that any teaching or research institution have a voltage source that allows the experimentation of the pollution phenomena at a minimum cost. [Espanol] En la costa del Golfo de Mexico y en el noroeste del pais hay severos problemas de contaminacion en los aisladores de los sistemas electricos de distribucion. Para solucionar este problema, se reproducen, en laboratorios especializados, las condiciones de contaminacion para su analisis cualitativo y cuantitativo. En general, con este proposito se han utilizado transformadores especiales de voltaje que por ser de importacion son muy costosos; ademas, no existe un criterio definido de seleccion que permita suministrar a la fuente de voltaje la corriente recomendada por el IEC (International Electrotechnical Commission). En este articulo se presenta una propuesta para seleccionar un transformador que cumpla con los requerimientos del IEC. Esta, por su facilidad de adquisicion y economia, permite que cualquier institucion docente o de investigacion cuente con una fuente de voltaje que permita la experimentacion de los fenomenos contaminantes con un costo minimo.
Active and reactive power control of a current-source PWM-rectifier using space vectors
Energy Technology Data Exchange (ETDEWEB)
Salo, M.; Tuusa, H. [Tampere University of Technology (Finland). Department of Electrical Engineering, Power Electronics
1997-12-31
In this paper the current-source PWM-rectifier with active and reactive power control is presented. The control system is realized using space vector methods. Also, compensation of the reactive power drawn by the line filter is discussed. Some simulation results are shown. (orig.) 8 refs.
DEFF Research Database (Denmark)
Mathe, Laszlo; Cornean, Horia; Sera, Dezso
2011-01-01
of the transfer ratio. The difference between most of the proposed modulation methods like sine-triangular, SVM, and 120 - 60 - 30 Discontinuous PWM consists in the redistribution of the time-length applied for the zero voltage vectors during a fundamental frequency period. This paper presents a unified...
Three Phase Six-Switch PWM Buck Rectifier with Power Factor Improvement
DEFF Research Database (Denmark)
Zafar Ullah Khan, M; Mohsin Naveed, M.; Hussain, Dil Muhammad Akbar
2013-01-01
Conventional Phase Controlled Rectifier injects low order current harmonics into the AC mains. Large size filtering components are required to attenuate these harmonics. In this paper, Three Phase Six-Switch PWM Buck Rectifier[1] is presented which operates at nearly unity power factor and provides...
Three Phase Six-Switch PWM Buck Rectifier with Power Factor Improvement
DEFF Research Database (Denmark)
Zafar Ullah Khan, M; Mohsin Naveed, M.; Hussain, Dil Muhammad Akbar
2013-01-01
Conventional Phase Controlled Rectifier injects low order current harmonics into the AC mains. Large size filtering components are required to attenuate these harmonics. In this paper, Three Phase Six-Switch PWM Buck Rectifier[1] is presented which operates at nearly unity power factor and provid...
PWM Flow Rate Control of ER Valve and its Application to ER Actuator Control
Nakano, Masami; Minagawa, Shuji; Hagino, Katsuya
The PWM (Pulse Width Modulation) control of ER valve consisting of two parallel electrodes has been investigated to continuously control the flow rate of an electrorheological (ER) suspension containing sulfonated polymer particles in silicone oil. PWM wave voltages are applied to the electrodes of the ER valve. It is possible to control continuously the flow rate by changing the duty ratio of the PWM wave from 1 to 0, where the duty ratio of 1 corresponds to the state to stop the flow. A miniature bellows actuator driven by a pair of PWM controlled ER valves has been developed, and the control characteristics of the actuator have been investigated. The duty ratios of both ER valves have been proposed to be changed alternately in proportion to the control voltage V to control the flow rate into and out of the bellows chamber, and also an overlap duty ratio Dov at V=0V has been introduced. The introduction of the overlap duty ratio Dov was found to be very important to smoothly control the actuator and to improve the control performance.
Six-Phase Vehicular Drive with Renewable DC Sources and Hybrid PWM Control of Four Inverters
DEFF Research Database (Denmark)
Oleschuk, Valentin; Ermuratskii, Vladimir; Blaabjerg, Frede
2015-01-01
The paper presents results of research of quad-inverter-based automotive system with combined scheme of PWM control of inverters, supplied by two renewable dc sources (by fuel cells and by battery). It has been shown, that hybrid switching techniques can be used successfully for control of vehicle...
High Power Density Power Electronic Converters for Large Wind Turbines
DEFF Research Database (Denmark)
Senturk, Osman Selcuk
In large wind turbines (in MW and multi-MW ranges), which are extensively utilized in wind power plants, full-scale medium voltage (MV) multi-level (ML) voltage source converters (VSCs) are being more preferably employed nowadays for interfacing these wind turbines with electricity grids...... assessments of these specific VSCs so that their power densities and reliabilities are quantitatively determined, which requires extensive utilization of the electro-thermal models of the VSCs under investigation. In this thesis, the three-level neutral-point-clamped VSCs (3L-NPC-VSCs), which are classified......-HB-VSCs). As the switch technology for realizing these 3L-VSCs, press-pack IGBTs are chosen to ensure high power density and reliability. Based on the selected 3L-VSCs and switch technology, the converter electro-thermal models are developed comprehensively, implemented practically, and validated via a full-scale 3L...
DC-DC converter for discharging energy storage magnets
Eyssa, Yehia M.; Huang, Xianrui
1994-07-01
A new DC-DC converter to control the output power delivered from a magnetic energy storage magnet or an equivalent current source is discussed. The circuit consists of: (1) highly coupled transformer (air or iron core) with coupling coefficient better than 0.95; (2) low frequency mechanical or superconducting switches (0.1 - 10 Hz) or high frequency (10 - 1000 Hz) GTO switches depending on the application; and (3) small voltage source (capacitor or battery) to control the output voltage. Two examples illustrating the application of this circuit are discussed. They are a step up dc current converter for use in uninterruptible power supplies and a step down one for use in discharging large current storage coil into a small current load. The efficiency expected to exceed 90%.
New DC/DC High Step Up Isolated Converter with ZVS
Directory of Open Access Journals (Sweden)
Ehsan Movahedi
2014-10-01
Full Text Available In this paper we presents a soft switch sepic, flyback converter. At first the converter have hard switching in main switch and completely analysis then added auxiliary circuit for soft switching Auxiliary circuit in the converter is not only soft switching condition for the main switch but also prevents the spike voltage across the main switch when turned off that because leakage inductance. Therefore, the proposed converter efficiency in comparison with the previous converters increased and voltage stress on the main switch is reduced. Also the auxiliary switch in the converter have soft switching and thereby decrese losses. this converter Control with pwm.These converter have higher efficiency than the similar converters and the cost is low. Auxiliary circuit in the converter is not only soft switching condition for the main switch but also prevents the spike voltage across the main switch when turned off that because leakage inductance. Therefore, the proposed converter efficiency in comparison with the previous converters increased and voltage stress on the main switch is reduced.
Directory of Open Access Journals (Sweden)
Jami Rajesh
2014-02-01
Full Text Available This paper deals with a novel type soft switching utility frequency AC- high frequency AC converter using asymmetrical PWM bidirectional active switches which can be defined as high frequency resonant matrix converter.This power frequency changer can directly convert utility frequency AC power to high frequency AC power ranging more than 20kHz up to 100kHz. Only one active edge resonant capacitor-assisted soft switching high frequency load resonant cyclo-converter is based on asymmetrical duty cycle PWM strategy. This high frequency cyclo-converter uses bidirectional IGBTs composed of anti-parallel one-chip reverse blocking IGBTs. This high frequency cycloconverter has some remarkable features as electrolytic capacitorless DC busline link, unity power factor correction and sinewave line current shaping, simple configuration with minimum circuit components and low cost, high efficiency and downsizing. This series load resonant cycloconverter incorporating bidirectional active power switches is developed and implemented for high efficiency consumer induction heated food cooking appliances. Its operating principle is described by using equivalent circuits. Its operating performances as soft switching operating ranges and high frequency effective power regulation characteristics are discussed on the basis of simulation and experimental results.
Ohyama, Kazuhiro; Sakamoto, Tsuyoshi; Arinaga, Shinji; Yamashita, Yukio
This paper proposes variable-speed wind generation system using the boost converter. The proposed system has three speed control modes for the wind velocity. The control mode of low wind velocity regulates the armature current of the generator with the boost converter to control the speed of wind turbine. The control mode of middle wind velocity regulates the DC link voltage with the vector controlled inverter to control the speed of wind turbine. The control mode of high wind velocity regulates the pitch angle of the wind turbine with the pitch angle control system to control the speed of wind turbine. The hybrid of three control modes extends the variable-speed range. The proposed system simplifies the maintenance and improves the reliability and reduces the cost in compare with the variable-speed wind generation system using PWM converter. This paper describes the control strategy and modeling for simulation using Matlab Simulink of the proposed system. Also this paper describes the control strategy and modeling of variable-speed wind generation system using PWM converter. The steady state and transient responses for wind velocity changes are simulated using the Matlab Simulink. This paper verifies the fundamental performance of the system using boost converter by discussing the simulation results of the both systems.
CCLIBS: The CERN Power Converter Control Libraries
AUTHOR|(SzGeCERN)404953; Lebioda, Krzysztof Tomasz; Magrans De Abril, Marc; Martino, Michele; Murillo Garcia, Raul; Nicoletti, Achille
2015-01-01
Accurate control of power converters is a vital activity in large physics projects. Several different control scenarios may coexist, including regulation of a circuit’s voltage, current, or field strength within a magnet. Depending on the type of facility, a circuit’s reference value may be changed asynchronously or synchronously with other circuits. Synchronous changes may be on demand or under the control of a cyclic timing system. In other cases, the reference may be calculated in real-time by an outer regulation loop of some other quantity, such as the tune of the beam in a synchrotron. The power stage may be unipolar or bipolar in voltage and current. If it is unipolar in current, it may be used with a polarity switch. Depending on the design, the power stage may be controlled by a firing angle or PWM duty-cycle reference, or a voltage or current reference. All these cases are supported by the CERN Converter Control Libraries (CCLIBS). These open-source C libraries include advanced reference generati...
DEFF Research Database (Denmark)
Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.
2013-01-01
A new pulse width modulation (PWM) strategy which is an alternative approach of discontinuous PWM (DPWM) for a three-level neutral point clamped (NPC) inverter is developed and presented in this paper. The proposed PWM scheme not only takes advantage of the special properties available in NPC...... can be simplified. The salient features of the proposed scheme, as compared with the existing carrier-based DPWM strategies, are: 1) its reduced computational processing time, 2) its capability to balance the DC-link voltage without any additional control and 3) its reduced complexity e.g. only one...
Realization of PWM Velocity Modulation in Hydraulic Elevator%PWM调速在液压电梯中的实现
Institute of Scientific and Technical Information of China (English)
唐国兴; 恽源世; 徐鸣谦
2001-01-01
This paper introduces the realization of velocity modulation control in hydraulic elevator by using PWM technology. It mainly includes two parts, one is about how to send out PWM signal via computer to perform the velocity modulation, and the other is about the design of manual PWM velocity modulation device.%介绍了运用PWM技术实现液压电梯的调速控制，主要包括两部分，一是用工控机发送PWM信号进行调速，二是手动PWM调速装置的设计。
National Research Council Canada - National Science Library
Hsin-Jang Shieh; Ying-Zuo Chen
2017-01-01
To efficiently supply wide-range DC voltage from a pulse-width modulation (PWM) rectifier, this paper presents a single-phase, full-wave, diode-bridge, single-ended primary-inductor converter-type (SEPIC-type...
Research on the Core Loss Model Under PWM Wave and DC Bias Excitations%PWM波及直流偏磁励磁下磁芯损耗模型研究
Institute of Scientific and Technical Information of China (English)
叶建盈; 陈为; 汪晶慧
2015-01-01
In order to evaluate and predict the core losses of magnetics in power converters, by equivalently replacing the dynamic B-H loop which surrounding area reflects the core losses in a magnetizing cycle period with an elliptical loop, the model of magnetics core losses under the PWM excitation without DC bias was derived. The core losses of magnetics under both DC bias and PWM excitations using a DC/AC inverter as the test circuit were measured by differential loss test idea. By the analysis of the core loss test results and their characteristics, a new core loss model considering the effects of both DC bias and PWM excitations was conceived based on the basic B-H curve. Finally, the test results were compared with the proposed model and the model accuracy was verified.%为了有效地评估和预测功率变换器中磁元件的磁芯损耗，将反映磁芯一个励磁周期内损耗的动态磁滞回线以椭圆回线等效，推导出了无直流偏磁工况下脉宽调制(pulse width modulation，PWM)波形励磁的磁芯损耗模型。采用差值损耗测量思想，以DC/AC逆变电路作为测试电路，测量了直流偏磁及PWM波励磁下的磁芯损耗。进一步根据直流偏磁下磁芯损耗的测量结果及其特征的分析，构思了以磁芯基本磁化曲线模型为基础的直流偏磁和 PWM 波励磁下的磁芯损耗模型。最后，对比了测试数据和所提出的模型的计算结果，验证了模型的正确性。
Directory of Open Access Journals (Sweden)
Yüksel Oğuz
2013-01-01
Full Text Available The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS operation in grid/load-connected mode are presented. VSWECS consists of a PMSG connected to a AC-DC IGBT-based PWM rectifier and a DC/AC IGBT-based PWM inverter with LCL filter. In VSWECS, AC/DC/AC power converter is employed to convert the variable frequency variable speed generator output to the fixed frequency fixed voltage grid. The DC/AC power conversion has been managed out using adaptive neurofuzzy controlled inverter located at the output of controlled AC/DC IGBT-based PWM rectifier. In this study, the dynamic performance and power quality of the proposed power converter connected to the grid/load by output LCL filter is focused on. Dynamic modeling and control of the VSWECS with the proposed power converter is performed by using MATLAB/Simulink. Simulation results show that the output voltage, power, and frequency of VSWECS reach to desirable operation values in a very short time. In addition, when PMSG based VSWECS works continuously with the 4.5 kHz switching frequency, the THD rate of voltage in the load terminal is 0.00672%.
Oğuz, Yüksel; Güney, İrfan; Çalık, Hüseyin
2013-01-01
The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS) operation in grid/load-connected mode are presented. VSWECS consists of a PMSG connected to a AC-DC IGBT-based PWM rectifier and a DC/AC IGBT-based PWM inverter with LCL filter. In VSWECS, AC/DC/AC power converter is employed to convert the variable frequency variable speed generator output to the fixed frequency fixed voltage grid. The DC/AC power conversion has been managed out using adaptive neurofuzzy controlled inverter located at the output of controlled AC/DC IGBT-based PWM rectifier. In this study, the dynamic performance and power quality of the proposed power converter connected to the grid/load by output LCL filter is focused on. Dynamic modeling and control of the VSWECS with the proposed power converter is performed by using MATLAB/Simulink. Simulation results show that the output voltage, power, and frequency of VSWECS reach to desirable operation values in a very short time. In addition, when PMSG based VSWECS works continuously with the 4.5 kHz switching frequency, the THD rate of voltage in the load terminal is 0.00672%.
Oğuz, Yüksel; Güney, İrfan; Çalık, Hüseyin
2013-01-01
The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS) operation in grid/load-connected mode are presented. VSWECS consists of a PMSG connected to a AC-DC IGBT-based PWM rectifier and a DC/AC IGBT-based PWM inverter with LCL filter. In VSWECS, AC/DC/AC power converter is employed to convert the variable frequency variable speed generator output to the fixed frequency fixed voltage grid. The DC/AC power conversion has been managed out using adaptive neurofuzzy controlled inverter located at the output of controlled AC/DC IGBT-based PWM rectifier. In this study, the dynamic performance and power quality of the proposed power converter connected to the grid/load by output LCL filter is focused on. Dynamic modeling and control of the VSWECS with the proposed power converter is performed by using MATLAB/Simulink. Simulation results show that the output voltage, power, and frequency of VSWECS reach to desirable operation values in a very short time. In addition, when PMSG based VSWECS works continuously with the 4.5 kHz switching frequency, the THD rate of voltage in the load terminal is 0.00672%. PMID:24453905
Kohara, Tatsuya; Noguchi, Toshihiko; Kondo, Seiji
In recent years, parallel-operation of inverters is employed to increase reliability and capacity in an uninterruptible power supply (UPS) system. A phase error in PWM carrier-signals of each inverter causes high frequency loop current between inverters. Therefore, the PWM carrier-signal of each inverter should be adjusted in phase. This paper proposes a detection method of phase error in PWM carrier-signal and its application to synchronization control for parallel-connected inverters. A simple definite-integral circuit achieves the detection of carrier phase error from high frequency loop current using no signal line between inverters. The detected carrier phase error is applied to synchronize the PWM carrier-signal through a PI-compensator, and then the high frequency loop current can be suppressed. Several experimental test-results show the validity of the proposed detection method and synchronization control.
New zero voltage switching DC converter with flying capacitors
Lin, Bor-Ren; Shiau, Tung-Yuan
2016-04-01
A new soft switching converter is presented for medium power applications. Two full-bridge converters are connected in series at high voltage side in order to limit the voltage stress of power switches at Vin/2. Therefore, power metal-oxide-semiconductor field-effect transistors (MOSFETs) with 600 V voltage rating can be adopted for 1200 V input voltage applications. In order to balance two input split capacitor voltages in every switching cycle, two flying capacitors are connected on the AC side of two full-bridge converters. Phase-shift pulse-width modulation (PS-PWM) is adopted to regulate the output voltage. Based on the resonant behaviour by the output capacitance of MOSFETs and the resonant inductance, active MOSFETs can be turned on under zero voltage switching (ZVS) during the transition interval. Thus, the switching losses of power MOSFETs are reduced. Two full-bridge converters are used in the proposed circuit to share load current and reduce the current stress of passive and active components. The circuit analysis and design example of the prototype circuit are provided in detail and the performance of the proposed converter is verified by the experiments.
Study on Control Strategies for the Multilevel Cascaded Converters
Directory of Open Access Journals (Sweden)
Lin Xu
2013-11-01
Full Text Available The multilevel cascaded converters are extensively applied for high-voltage and high-power applications, which are considered as the most favorable topologies for the high power ac-drives and the high-voltage DC transmission (HVDC systems using the voltage source converters (VSCs. This paper presents the dc capacitor balancing and effective current regulation methodologies for the multilevel cascaded converters. The dc-link voltage balancing and capacitor energy evolving mechanism of the MMCC is analyzed, and an effective control scheme is devised by utilizing two dc capacitor voltage control loops, including the total capacitor voltage controller (TCVC, the capacitor voltage balancing controller (CVBC. The predictive current controller is proposed to enhance the tracking accuracy of current control loop. The proportional-resonant controller (PRC is used as circulating current damping controller of the modular multilevel converter, which is found to be highly effective to minimize the circulating current. The Electromagnetic Transient Program (EMTP is utilized for digital simulation of the single-phase five-level modular multilevel converter. The effectiveness of the control scheme is validated by the simulation results.
Analysis of Discontinuity Induced Bifurcations in a Dual Input DC-DC Converter
Giaouris, Damian; Banerjee, Soumitro; Mandal, Kuntal; Al-Hindawi, Mohammed M.; Abusorrah, Abdullah; Al-Turki, Yusuf; El Aroudi, Abdelali
DC-DC power converters with multiple inputs and a single output are used in numerous applications where multiple sources, e.g. two or more renewable energy sources and/or a battery, feed a single load. In this work, a classical boost converter topology with two input branches connected to two different sources is chosen, with each branch independently being controlled by a separate peak current mode controller. We demonstrate for the first time that even though this converter is similar to other well known topologies that have been studied before, it exhibits many complex nonlinear behaviors that are not found in any other standard PWM controlled power converter. The system undergoes period incrementing cascade as a parameter is varied, with discontinuous hard transitions between consecutive periodicities. We show that the system can be described by a discontinuous map, which explains the observed bifurcation phenomena. The results have been experimentally validated.
A AC-DC Inversion Power Design Based on PWM IC Controller%基于PWM IC芯片控制的开关电源设计
Institute of Scientific and Technical Information of China (English)
王玉德; 韩翠玲; 陈春廷; 孙洪海
2008-01-01
介绍了SG3525 PWM IC芯片的内部结构,基于该芯片设计了15V/36V的开关电源.设计中给出具体的设计电路和参数.经过实验验证该系统控制可靠,稳定性好,纹波系数低,能够很好地适应电源电压10%和负载20%的变化,具有一定的实际应用价值.
Differential Mode EMI Filter Design for Isolated DC-DC Boost Converter
DEFF Research Database (Denmark)
Makda, Ishtiyaq Ahmed; Nymand, Morten
2014-01-01
is identified first. The DM noise model is then established and based on the harmonic analysis of the noise source voltage waveform, the complete Differential Mode EMI filter, including the filter resonance damping branch, is designed for a 3kW isolated dc-dc boost converter. The noise model and its theoretical......A Differential Mode EMI filter for a low input voltage high-current isolated dc-dc boost converter is designed and presented in this paper. The primary side Differential Mode noise voltage is low due to the high transformer turn ratio, however, the input current is very high and since the EMI limit...... also does not change for such converters, it requires greatly optimized design approach for the filter including the correct sizing of the filter components. A complete analytical filter design process is carried out such a way that the Differential Mode noise voltage source in the converter...
Theory of multi-phase PWM DC/DC converter%多相PWM控制DC/DC变换器
Institute of Scientific and Technical Information of China (English)
陈小明
2001-01-01
@@ 概述 近年来,随着一些高性能CPU的出现,如Pentium 4、Athlon等,需要输出电压更小,更大电流的DC/DC变换器,对热性能、EMI及负载瞬变应答(Load Transient)的要求也不断提高.传统的单相DC/DC变换器日益显示出局限性.多相DC/DC变换器以其独特的性能,为高性能CPU电源的解决方案开辟的一条新路.
Directory of Open Access Journals (Sweden)
Abdul Aziz Mohammed Al Buaijan,
2014-08-01
Full Text Available Presenting in his paper, Digital signal processor (DSP-based implementation of a single phase unified power flow controller (UPFC. For shunt side and series side An efficient UPFC control algorithm is achieved. Discussing the laboratory experimental results using DC source are taken as an UPFC linked by two ll-bridge PWM voltage source converters.
两级并联单相电压源整流器的无源性控制%Passivity Control over Dual-interleaved Single-phase Voltage Source Rectifier
Institute of Scientific and Technical Information of China (English)
马红星; 李华武; 杨喜军
2013-01-01
单相电压源整流器(VSR)是一种四象限的AC-DC变换器,可以应用于单相有源电力滤波器和固态变压器.为了提高功率等级,需要采用多个单相VSR输入并联和输出并联的工作方式,为此需要解决各级单相VSR之间的均流问题.提出了一种基于无源性控制的均流方案,首先在理论上证明了单级和两级单相VSR均为无源性系统,且可以产生良好的均流效果.在此基础上,采用MATLAB/SIMULINK进行了仿真验证.结果表明,在功率电路主要参数不一致的情况下,采用无源性控制、交错控制的两级并联单相VSR具有良好的均流效果,网侧功率因数接近于1,输出直流电压幅值可调,并且允许多级单相VSR并联.%Single-phase voltage source rectifier (VSR) is a four-quadrant AC/DC converter,which can be used in many applications,such as single-phase active power filter and solid state transformer.In order to achieve much higher output power,it is applicable to employ parallel cornections both at its input side and output side.However,it is required to solve the issue of current sharing among the different single-phase VSRs.Considering the above referred,a current sharing method based on passivity theory was proposed.At first,what proved was that single-stage VSR and two-stage single-phase VSR were characteristic of passivity-based system theoretically,which could bring about easy current sharing.Then the above theoretical analysis was simulated and verified by means of MATLAB/SIMULINK.The results show that passivity-based control and interleaving control can achieve current sharing even in case of inconsistent parameters,and the power factor at grid side approaches one and DC output voltage can be regulated.Thus it is allowed that more single-stage VSRs are connected in parallel both at input side and output side without current sharing problem.
Directory of Open Access Journals (Sweden)
SANJEEV SINGH
2010-12-01
Full Text Available Permanent magnet brushless DC motor (PMBLDCM drives are being employed in many variable speed applications due to their high efficiency, silent operation, compact size, high reliability, ease of control, and low maintenance requirements. These drives have power quality problems and poor power factor at input AC mains as they are mostly fed through diode bridge rectifier based voltage source inverters. To overcome such problems a single-phase single-switch power factor correction AC-DC converter topology based on a Cuk converter is proposed to feed voltage source inverters based PMBLDCM. It focuses on the analysis, design and performance evaluation of the proposed PFC converter topology for a 1.5 kW, 1500 rpm, 400 V PMBLDCM drive used for an air-conditioning system. The proposed PFC converter topology is modelled and its performance is simulated in Matlab-Simulink environment and results show an improved power quality and good power factor in wide speed range of the drive.
Salehifar, Mehdi; Moreno-Equilaz, Manuel
2016-01-01
Due to its fault tolerance, a multiphase brushless direct current (BLDC) motor can meet high reliability demand for application in electric vehicles. The voltage-source inverter (VSI) supplying the motor is subjected to open circuit faults. Therefore, it is necessary to design a fault-tolerant (FT) control algorithm with an embedded fault diagnosis (FD) block. In this paper, finite control set-model predictive control (FCS-MPC) is developed to implement the fault-tolerant control algorithm of a five-phase BLDC motor. The developed control method is fast, simple, and flexible. A FD method based on available information from the control block is proposed; this method is simple, robust to common transients in motor and able to localize multiple open circuit faults. The proposed FD and FT control algorithm are embedded in a five-phase BLDC motor drive. In order to validate the theory presented, simulation and experimental results are conducted on a five-phase two-level VSI supplying a five-phase BLDC motor.
Microcontroller based PWM controlled four switch three phase inverter fed induction motor drive
Directory of Open Access Journals (Sweden)
Mohanty Kant Nalin
2010-01-01
Full Text Available This paper presents PIC microcontroller based PWM inverter controlled four switch three phase inverter (FSTPI fed Induction Motor drive. The advantage of this inverter that uses of 4 switches instead of conventional 6 switches is lesser switching losses, lower electromagnetic interference (EMI, less complexity of control algorithms and reduced interface circuits. Simulation and experimental work are carried out and results presented to demonstrate the feasibility of the proposed approach. Simulation is carried out using MATLAB SIMULINK and in the experimental work a prototype model is built to verify the simulation results. PIC microcontroller (PIC 16F877A is used to generate the PWM pulses for FSTPI to drive the 0.5 hp 3-phase Induction Motor.
Moment Stability of the Critical Case of PWM Feedback Systems with Stochastic Perturbations
Directory of Open Access Journals (Sweden)
Zhong Zhang
2012-01-01
Full Text Available This paper further studies the moment stability of pulse-width-modulated (PWM feedback system which is subjected to multiplicative and additive random disturbance modeled by the derivative of Wiener process. Different from the existing investigation, we focus on its critical case. The linear plant considered herein is assumed to be critically stable; that is, the plant has one and only one pole at the origin, and the rest of the poles are left half of complex plane. We establish several globally asymptotically stability criteria for such PWM feedback systems and then propose an algorithm to calculate the stability bound effectively. Furthermore, we present two numerical examples to show the effectiveness of the theoretical results.
Conversor Boost PWM Entrelaçado com Comutação Suave
Directory of Open Access Journals (Sweden)
Lúcio dos Reis Barbosa
2002-01-01
Full Text Available Este artigo apresenta uma topologia aprimorada de um conversor Boost PWM com comutação suave. O circuito proposto, tendo duas chaves ativas entrelaçadas, opera com chaveamento suave, sob odulação PWM (pulse-width-modulation. Além disso, este conversor fornece alta rendimento sob as condições de operação, para uma larga variação de carga, e operando à altas freqüências. Para ilustrar o princípio de operação deste novo conversor apresenta-se um estudo pormenorizado, incluindo simulações e resultados. A validade deste novo conversor é confirmada por meio dos resultados obtidos.
High-Frequency Link Inverter for Fuel CellsBased on Multiple-Carrier PWM
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
A similar circuit as Fig. 12 can be realized with MOSFET or IGBT devices configured as bi-directional pairs in the output bridge. In this case, the complete process in Fig. 8 would be needed to generate the complete 50% gate drive pulses. The 50% gate pulses still support pulse transformer coupling, retaining the simplicity of the gate drive isolation. The PWM cycloconverter process scales directly to higher switching speeds possible with these devices.
Modelling of a double star induction motor for space vector PWM control
Energy Technology Data Exchange (ETDEWEB)
Hadiouche, D.; Razik, H.; Rezzoug, A. [Groupe de Recherche en Electrotechnique et Electronique de Nancy, G.R.E.E.N. - CNRS UPRES, University H. Poincare, Vandoeuvre-les-Nancy (France)
2000-08-01
In this paper, we present the analysis and the modelling of a Double-Star Induction Motor (DSIM). A steady-state model is first established in order to analyse its harmonic behaviour. Then, a new transformation matrix is proposed in order to develop a suitable dynamic model. In both cases, the study is made using an arbitrary shift angle between the two stars. At last, a space vector Pulse Width Modulation (PWM) control or the DSIM is simulated. (orig.)
Nonlinear Control of an Open-Loop Open-Winding Motor System with Modulated Converters
Directory of Open Access Journals (Sweden)
Oleschuk V.I.
2017-04-01
Full Text Available Purpose of this work - to provide wider control opportunities for multiphase open-end winding motor drive by modification of basic scheme of space-vector pulse-width modulation (PWM. It has been shown, that the proposed development of basic PWM scheme insures available solutions for realization of specific control dependences and modes of operation of adjustable speed ac drives with different types and kinds of loads. Suitable algorithms of PWM of converters of multiphase drive have been analyzed and compared. Extensive simulation studies have been executed for evaluation of performance and effectiveness of the proposed control strategy. Assessment of harmonic composition of the phase voltages of drive system with modified scheme of space-vector modulation has been done. Results of the executed simulations proved the fact, that the developed techniques of space-vector pulse-width modulation allow providing quarter-wave or half-wave symmetry of waveforms of the output voltage of six-phase adjustable speed drive systems during the analyzed non-standard modes and regimes of its operation.
A New PWM Modifying Technique for Reconstructing Three-phase Currents from DC Bus Current
Aoyagi, Shigehisa; Iwaji, Yoshitaka; Tobari, Kazuaki; Sakamoto, Kiyoshi
Vector control is used to drive a DC brushless motor and generally needs current information. DC bus current detection is often adopted as a low cost method for reconstructing three-phase currents. PWM modifying techniques increase the DC pulse duration, thereby enabling easy detection of the DC bus current. However, these techniques have two problems: reducing a noise frequency and making the reconstructed current waveforms distorted by current ripple. In the techniques, modification signals are added to the three-phase voltage commands; the sum of the signals over a single cycle is zero. The authors examined several PWM modifying techniques from the points of view of noise and current distortion performance. One of the techniques had a good noise performance, and the frequency component of the noise was the same as the carrier frequency (fc). However, the reconstructed current waveforms were distorted. The total harmonic distortion (THD) varied from 1.7% to 4.1%. Another technique had a very poor noise performance, and the frequency component on the noise was one-fourth of fc. The authors developed a new PWM modifying method called “Half Pulse Shift”, which achieves the optimum noise and current distortion performance. The frequency component of the new method was two-thirds of fc, and the current waveforms were not distorted; the THD in the simulations and experiments was 0.5%-1.4% and 3.4%-3.6%, respectively.
Chunhong, Zhang; Haigang, Yang; Shi, Richard
2013-06-01
A synchronous buck DC—DC converter with an adaptive multi-mode controller is proposed. In order to achieve high efficiency over its entire load range, pulse-width modulation (PWM), pulse-skip modulation (PSM) and pulse-frequency modulation (PFM) modes were integrated in the proposed DC—DC converter. With a highly accurate current sensor and a dynamic mode controller on chip, the converter can dynamically change among PWM, PSM and PFM control according to the load requirements. In addition, to avoid power device damage caused by inrush current at the start up state, a soft-start circuit is presented to suppress the inrush current. Furthermore, an adaptive slope compensation (SC) technique is proposed to stabilize the current programmed PWM controller for duty cycle passes over 50%, and improve the degraded load capability due to traditional slope compensation. The buck converter chip was simulated and manufactured under a 0.35 μm standard CMOS process. Experimental results show that the chip can achieve 79% to 91% efficiency over the load range of 0.1 to 1000 mA
Institute of Scientific and Technical Information of China (English)
Zhang Chunhong; Yang Haigang; Richard Shi
2013-01-01
A synchronous buck DC-DC converter with an adaptive multi-mode controller is proposed.In order to achieve high efficiency over its entire load range,pulse-width modulation (PWM),pulse-skip modulation (PSM)and pulse-frequency modulation (PFM) modes were integrated in the proposed DC-DC converter.With a highly accurate current sensor and a dynamic mode controller on chip,the converter can dynamically change among PWM,PSM and PFM control according to the load requirements.In addition,to avoid power device damage caused by inrush current at the start up state,a soft-start circuit is presented to suppress the inrush current.Furthermore,an adaptive slope compensation (SC) technique is proposed to stabilize the current programmed PWM controller for duty cycle passes over 50％,and improve the degraded load capability due to traditional slope compensation.The buck converter chip was simulated and manufactured under a 0.35μm standard CMOS process.Experimental results show that the chip can achieve 79％ to 91％ efficiency over the load range of 0.1 to 1000 mA.
Energy Technology Data Exchange (ETDEWEB)
Ljusev, P.
2004-03-15
In this report an isolated PWM DC-AC SICAM with an active capacitive voltage clamp is presented. AC-DC power supply is implemented in its simplest form: diode rectifier followed by a medium-size charge-storage capacitors and possibly with an EMC filter on the mains entrance. Isolation from the AC mains is achieved using a high frequency (HF) transformer, whose voltages are not audio-modulated. The latter simplifies the design and is expected to have many advantages over the approach where the transformer voltages are modulated in regards to the audio signal reference. Input stage is built as a DC-AC inverter (push-pull, half-bridge or a full-bridge) and operated with 50% duty cycle, with all the challenges to avoid transformer saturation and obtain symmetrical operation. On the secondary side the output section is implemented as rectifier+inverter AC-AC stage, i.e. a true bidirectional bridge, which operation is aimed towards amplification of the audio signal. In order to solve the problem with the commutation of the load current, a dead time between the incoming and outgoing bidirectional switch is implemented, while a capacitive voltage clamp is used to keep the induced overvoltage to reasonable levels. The energy stored in the clamping capacitor is not wasted as in the dissipative clamps, but is rather transferred back to the primary side for further processing using an auxiliary isolated single-switch converter, i.e. an active clamping technique is used. (au)
Institute of Scientific and Technical Information of China (English)
胡跃伟; 鲁明; 田利梅; 武登云
2014-01-01
控制力矩陀螺框架电机驱动电路采用的脉宽调制方式不同,所产生的电机转矩脉动也会不同.针对无刷直流电机驱动的控制力矩陀螺框架系统,从换相期间转矩脉动、非换相期间转矩脉动及脉宽调制方式的应用改进3个方面对不同脉宽调制方式进行分析,得出采用PWM_ON PWM方式的转矩脉动最小,适用于控制力矩陀螺框架系统的高精度控制要求.通过仿真验证了分析的正确性.
Lorenzo, J., Jr.; Espiritu, J. C.; Mediavillo, J.; Dy, S. J.; Caldo, R. B.
2017-06-01
This paper aims to develop and implement a Sugeno-style fuzzy inference system using a microcontroller for buck and boost DC-to-DC converter. The buck converter circuit is given an input voltage range of 4-5V and expected to have an output voltage of 1.5V, while the boost converter has an input voltage range of 2-3V and expected to have an output voltage of 15V. A microcontroller will be used for the input values, PWM signal, which is supplied through the MOSFET. The constants in the program in the microcontroller were manipulated to acquire desired accurate output voltages wherein the concept of fuzzy logic was applied. The proponents achieved less than 2.5% tolerance in the buck converter and less than 5% in the boost converter.
Directory of Open Access Journals (Sweden)
Yanbin Hou
2016-01-01
Full Text Available Compared with conventional Class-A, Class-B, and Class-AB amplifiers, Class-D amplifier, also known as switching amplifier, employs pulse width modulation (PWM technology and solid-state switching devices, capable of achieving much higher efficiency. However, PWM-based switching amplifier is usually designed for low-voltage application, offering a maximum output voltage of several hundred Volts. Therefore, a step-up transformer is indispensably adopted in PWM-based Class-D amplifier to produce high-voltage output. In this paper, a switching amplifier without step-up transformer is developed based on digital pulse step modulation (PSM and hybrid multilevel converter. Under the control of input signal, cascaded power converters with separate DC sources operate in PSM switch mode to directly generate high-voltage and high-power output. The relevant topological structure, operating principle, and design scheme are introduced. Finally, a prototype system is built, which can provide power up to 1400 Watts and peak voltage up to ±1700 Volts. And the performance, including efficiency, linearity, and distortion, is evaluated by experimental tests.
A Novel Dual-input Isolated Current-Fed DC-DC Converter for Renewable Energy System
DEFF Research Database (Denmark)
Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.
2010-01-01
In this paper, a novel isolated current-fed DC-DC converter (boost-type) with two input power sources based on multi-transformer structure, which is suitable for fuel cells and super-capacitors hybrid energy system, is proposed and designed. With particular transformer windings connection strategy......, the proposed converter can draw power from two different DC sources with lower voltage and deliver it to the higher voltage DC bus or load individually and simultaneously. The detailed operation principle of the proposed converter has been analyzed in dual-input mode and single-input mode, respectively....... Furthermore, the method to increase the number of input ports, the magnetic integration structure, and ground loop decoupling are discussed. Experimental results from the lab prototype converter with two DC voltage sources verify the validity of the theoretical analysis and design of the converter....
DEFF Research Database (Denmark)
Makda, Ishtiyaq Ahmed; Nymand, Morten
2015-01-01
This paper presents the common-mode noise analysis and modeling of a phase-shifted full-bridge forward converter. The common-mode noise source due to a transformer inter-winding capacitance is considered for the case of study. The generated common-mode noise voltage-source in a converter...... is analytically determined, which then leads to a common-mode noise modeling of a phase-shifted converter. Using a proposed model, common-mode noise-current harmonics are calculated and a fully analytical filter design procedure is presented to comply with the CISPR-11 standard. Finally, a prototype phase......-shifted forward converter is built to verify the theoretical analysis. This study shows that the primary-to-secondary transformer winding capacitance creates a very significant amount of common-mode noise current in a phase-shifted forward converter....
Design of Load Current Feedforward PWM Rectifier Based on STM32%基于STM32的负载电流前馈PWM整流器设计
Institute of Scientific and Technical Information of China (English)
黄金飞; 唐小琦; 宋宝; 程建军
2015-01-01
For three-phase voltage source PWM rectifier under the traditional double closed-loop PI control strategy, the output dc voltage fluctuates with load current and the adjustment lasts long. By analyzing the disturbance response of the system, a load current feedforward control strategy is put forward. The disturb-ance current is measured directly as the faster current loop input instruction. This method overcomes the de-lay of the cascading closed-loop adjustment, so as to improve the dynamic response performance. An im-proved rectifier device was designed based on STM32F103Z. Three high speed ADs, an advanced timer TIM1, an integrated USB module and other on chip resources were used. The experimental results show that the load current feed-forward PWM rectifier based on STM32 has dramatically improved anti-load disturb-ance performance.%针对三相电压型PWM整流器在传统双闭环PI控制策略下，输出直流电压会随负载电流波动并且调整时间长这一问题，在分析系统扰动响应的基础上，提出了负载电流前馈控制方法。通过直接测量扰动电流，并将其作为电流环输入指令，以克服级联闭环调节带来的延迟，使得整流器输出电流紧紧跟随负载电流，进而提高输出电压的动态响应。为验证控制策略的可行性和有效性，利用STM32 F103 Z芯片的3个12位AD、高级定时器TIM1、集成USB模块等片上资源搭建了改进的整流装置，实验结果表明，基于STM32的负载电流前馈PWM整流器抗负载扰动能力得到了明显改善。
Grid converter for LED based intelligent light sources
DEFF Research Database (Denmark)
Török, Lajos
to reduce the size of the magnetic components. A description of different grid regulations was given followed by a set of converter topologies and controllers. Different control techniques were pointed out. Among the listed topologies and control solutions few were selected for further analysis, design...... controllers can be designed. The controller design was interconnected with the hardware design and control platform. Thus two dfferent prototypes were designed and built with two dierent digital controllers and the controller design, analysis and implementation was based on these two case studies. The first...... of the PI controller. All four control loops were implemented in a 16 bitfixed point dsPIC33FJ32GS406 microcontroller driving at the same time 8 PWM channels. Finally a brief analysis was done on the eect of the grid disturbances, especially voltage sags on the digital controller. Dierent grid codes...
A novel single phase buck PFC converter in discontinuous capacitor voltage mode operation
Institute of Scientific and Technical Information of China (English)
邓超平; 凌志斌; 叶芃生
2003-01-01
A novel single-phase Buck converter for power factor correction is proposed. It features simple control due to the constant duty ratio PWM used. It can obtain unity power factor by selecting a suitable LC filter at its input to force the voltage of capacitor to operate in discontinuous capacitor voltage mode. And by using another resonant LC filter at its output, it can not only eliminate the input current distortion at the vicinity of the zero crossing of the supply but also drastically reduce the 100 Hz output voltage ripple. The validity of analysis is confirmed by simulation results and experimental results.
Device Loading and Efficiency of Modular Multilevel Converter under Various Modulation Strategies
DEFF Research Database (Denmark)
Liu, Hui; Ma, Ke; Blaabjerg, Frede
2016-01-01
Modular Multilevel Converter (MMC) has been becoming a very important solution for high power and medium power applications, where the efficiency and reliability performance are crucial design considerations. In this paper, three widely used modulation methods for MMC, Phase Shift PWM (PSPWM...... of the power devices in terms of power loss and thermal profiles, which are critical issues in terms of efficiency and reliability of the MMC. Special attention is given to the performance comparison of MMC under various modulation indexes as well as different switching frequencies when applying those...
DC-link voltage balancing in cascaded H-Bridge converters
Directory of Open Access Journals (Sweden)
Lewicki Arkadiusz
2014-09-01
Full Text Available In this paper a DC-link voltage balancing strategy for multilevel Cascaded H-Bridge (CHB converter is proposed. Presented solution bases on optimal choice of active vector durations in Space-Vector Pulse Width Modulation (SV-PWM. It makes it possible to DC-link voltages control and to properly generate the output voltage vector in the case of DC-link voltage unbalance. Results of simulation and experimental researches on proposed control strategy are presented in the paper
汽车 ABS 电机 PWM 控制方法研究%Research on ABS motor PWM control
Institute of Scientific and Technical Information of China (English)
初亮; 祁富伟; 王彦波; 蔡健伟
2014-01-01
通过对ABS工作过程中制动液流量的分析，确定了ABS电机的基本工作要求。结合ABS电机的工作特性，采用基于逻辑门限值的PWM控制方法控制电机。运用DSpace搭建快速原型试验台，对比在不同电机工作转速、PWM控制频率下的噪声和制动踏板感觉，优化逻辑门限值大小，得出合理的工作方式，使电机既能满足控制要求，又有较长的寿命。通过在不同路面的试验结果对该控制方法的两个关键参数进行了优化。最后进行不同工况的试验，结果表明：通过优化控制参数的PWM 控制方法，具有较强的鲁棒性，能够满足ABS在任何工作条件下对电机的要求。%T hrough the characteristics of the flow of brake fluid during ABS (anti-lock braking sys-tem) working process ,the basic requirements of ABS motor was determined and the PWM (pulse width modulation) control based logic threshold was adapted .A rapid prototyping test bench with DSpace was built .The logic threshold values were optimized by comparing the noise and the pedal stroke when various motor speed and PWM frequency were used .Then a much more reasonable con-trol method can be got w hich makes the motor to meet the control requirements and also has a longer life .After a lot of tests on different test track ,the key control parameters were optimized .Finally , the control method was tested under different road conditions and various load conditions .The results show that the control method is robust and meet the ABS requirements to the motor under any work conditions .
Wavelength converter technology
DEFF Research Database (Denmark)
Kloch, Allan; Hansen, Peter Bukhave; Poulsen, Henrik Nørskov;
1999-01-01
Wavelength conversion is important since it ensures full flexibility of the WDM network layer. Progress in optical wavelength converter technology is reviewed with emphasis on all-optical wavelength converter types based on semiconductor optical amplifiers....
Wavelength converter technology
DEFF Research Database (Denmark)
Kloch, Allan; Hansen, Peter Bukhave; Poulsen, Henrik Nørskov;
1999-01-01
Wavelength conversion is important since it ensures full flexibility of the WDM network layer. Progress in optical wavelength converter technology is reviewed with emphasis on air-optical wavelength converter types based on semiconductor optical amplifiers....
Technologies for converter topologies
Energy Technology Data Exchange (ETDEWEB)
Zhou, Yan; Zhang, Haiyu
2017-02-28
In some embodiments of the disclosed inverter topologies, an inverter may include a full bridge LLC resonant converter, a first boost converter, and a second boost converter. In such embodiments, the first and second boost converters operate in an interleaved manner. In other disclosed embodiments, the inverter may include a half-bridge inverter circuit, a resonant circuit, a capacitor divider circuit, and a transformer.
Power Converters for Accelerators
Visintini, R
2015-01-01
Particle accelerators use a great variety of power converters for energizing their sub-systems; while the total number of power converters usually depends on the size of the accelerator or combination of accelerators (including the experimental setup), the characteristics of power converters depend on their loads and on the particle physics requirements: this paper aims to provide an overview of the magnet power converters in use in several facilities worldwide.
Optimized MPPT algorithm for boost converters taking into account the environmental variables
Petit, Pierre; Sawicki, Jean-Paul; Saint-Eve, Frédéric; Maufay, Fabrice; Aillerie, Michel
2016-07-01
This paper presents a study on the specific behavior of the Boost DC-DC converters generally used for powering conversion of PV panels connected to a HVDC (High Voltage Direct Current) Bus. It follows some works pointing out that converter MPPT (Maximum Power Point Tracker) is severely perturbed by output voltage variations due to physical dependency of parameters as the input voltage, the output voltage and the duty cycle of the PWM switching control of the MPPT. As a direct consequence many converters connected together on a same load perturb each other because of the output voltage variations induced by fluctuations on the HVDC bus essentially due to a not insignificant bus impedance. In this paper we show that it is possible to include an internal computed variable in charge to compensate local and external variations to take into account the environment variables.
DEFF Research Database (Denmark)
Isidori, Andrea; Rossi, Fabio Mario; Blaabjerg, Frede
2012-01-01
. Furthermore, the increment of the wind roughness class causes a larger dispersion of the mean values and the variation of the junction temperatures, also affecting the lifetime of the converter. Hence, the cycles lifetime largely decreases considering variable wind speed profile. In fact, the results show......This paper focuses on the design, thermal loading and reliability of a three-level Neutral Point Clamped (3-L NPC) back-to-back full scale converter for a 10 MW direct-drive wind turbine equipped with a Permanent Magnet Synchronous Generator (PMSG). The reliability performance of the three...... the dynamics of the system using different kinds of modulation strategies and analyzing different wind load conditions dependent on roughness classes. It is concluded that 60° discontinuous PWM modulation strategies show better thermal performance and increase the estimated lifetime of the converter...
A Color LED Driver Implemented by the Active Clamp Forward Converter
Directory of Open Access Journals (Sweden)
C. H. Chang
2013-03-01
Full Text Available Because light emitting diodes (LEDs have the advantages of dc working voltage, high luminescent efficiency, shortignition time, high reliability and pollution free, they have substituted for incandescent bulbs and fluorescent lampsgradually. In order to simplify circuit complexity, an active clamp forward converter with the sequential color display(SCD control is proposed to drive red, green and blue (RGB LED arrays. The proposed converter has zero-voltageswitching (ZVS operations of both the main switch and the auxiliary switch, resulting in high system efficiency. DrivingRGB LED arrays sequentially by one converter can save components and reduce cost significantly. Additionally, thepulse-width modulation (PWM control is applied to achieve a large chromaticity variation. The circuit operations areanalyzed in detail and the circuit parameters are designed based on the practical considerations. Finally, an illustrativeexample is implemented to demonstrate the feasibility and validity of the proposed LED driver.
Highly Sensitive and Wide-Dynamic-Range Multichannel Optical-Fiber pH Sensor Based on PWM Technique.
Khan, Md Rajibur Rahaman; Kang, Shin-Won
2016-11-09
In this study, we propose a highly sensitive multichannel pH sensor that is based on an optical-fiber pulse width modulation (PWM) technique. According to the optical-fiber PWM method, the received sensing signal's pulse width changes when the optical-fiber pH sensing-element of the array comes into contact with pH buffer solutions. The proposed optical-fiber PWM pH-sensing system offers a linear sensing response over a wide range of pH values from 2 to 12, with a high pH-sensing ability. The sensitivity of the proposed pH sensor is 0.46 µs/pH, and the correlation coefficient R² is approximately 0.997. Additional advantages of the proposed optical-fiber PWM pH sensor include a short/fast response-time of about 8 s, good reproducibility properties with a relative standard deviation (RSD) of about 0.019, easy fabrication, low cost, small size, reusability of the optical-fiber sensing-element, and the capability of remote sensing. Finally, the performance of the proposed PWM pH sensor was compared with that of potentiometric, optical-fiber modal interferometer, and optical-fiber Fabry-Perot interferometer pH sensors with respect to dynamic range width, linearity as well as response and recovery times. We observed that the proposed sensing systems have better sensing abilities than the above-mentioned pH sensors.
System Aspects and Modulation Strategies of an HVDC-based Converter System for Wind Farms
Energy Technology Data Exchange (ETDEWEB)
Meier, Stephan
2009-05-15
In this thesis, a new HVDC-based converter system for wind farms is investigated. It is based on a mutually commutated soft-switching converter system and provides a unique integrated solution for the wind turbine generator drive systems, the wind turbine interconnection, and the power conversion for HVDC transmission. In a wind farm, the mutually commutated converter system is a distributed system. A medium-frequency collection grid connects the converter station, equipped with a single-phase voltage source converter and a medium-frequency transmission transformer, with the wind turbines, each containing a cyclo converter and a medium-frequency distribution transformer. In this thesis, various system aspects regarding the application of a distributed mutually commutated converter system in a wind farm are investigated. Special attention is paid to the design of a medium-frequency collection grid that has an acceptable level of transient over voltages, the design of medium-frequency transformers with suitable magnetic, electric and thermal properties, and the development of a strategy to commutate the voltage source converter during low power generation. In order to adapt the mutually commutated converter system for an application in a wind farm, it had to be further developed. Different carrier-based and space-vector oriented modulation methods have been investigated. It turns out that for any load angle there is a quasi-discontinuous pulse width modulation strategy that can produce the same pulse patterns as space vector modulation. In addition, a modulation strategy has been developed that allows to replace the IGBTs in the cyclo converter with cheap, robust, and reliable fast thyristors, despite their absence of turn-off capability. The feasibility of different modulation strategies for mutually commutated converter systems has been verified on a down-scaled prototype converter system with both IGBT- and thyristor-based cyclo converters. Finally, a feasible
DEFF Research Database (Denmark)
Andresen, Markus; Ma, Ke; Liserre, Marco
2015-01-01
A Smart Transformer (ST) can cover an important managing role in the future electrical distribution grid. For the moment, the reliability and cost are not competitive with traditional transformers and create a barrier for its application. This work conduct detail designs and analysis for a promis......A Smart Transformer (ST) can cover an important managing role in the future electrical distribution grid. For the moment, the reliability and cost are not competitive with traditional transformers and create a barrier for its application. This work conduct detail designs and analysis...... for a promising modular ST solution, which is composed of Modular Multi-level converter, Quad Active Bridge DC-DC converters, and two-level voltage source converters. The focus is put on the loading conditions and thermal stress of power semiconductor devices in order to discover critical parts of the whole...
Design of 0.18 μm CMOS bandgap reference voltage source%0.18μm CMOS带隙基准电压源的设计
Institute of Scientific and Technical Information of China (English)
陈双文; 刘章发
2011-01-01
Reference voltage source can be used broadly in ADC, DAC, RAM, flash memory and other integrated circuit. This paper designed a high stability, low temperature coefficient and 0.6 V output bandgap reference voltage source using 0.18 μm CMOS.%基准电压源可广泛应用于A/D、D/A转换器、随机动态存储器、闪存以及系统集成芯片中.使用0.18 μm CMOS工艺设计了具有高稳定度、低温漂、低输出电压为0.6 V的CMOS基准电压源.
适用于电压源型高压直流输电的控制策略%A Novel Control Strategy for Voltage Sourced Converters Based HVDC
Institute of Scientific and Technical Information of China (English)
胡兆庆; 毛承雄; 陆继明
2005-01-01
将电压源型高压直流输电(VSC-HVDC)两端节点等效为两个有源节点,推导得到VSC-HVDC两端等效节点注入电流的表达式,从而可以方便地通过修改系统导纳矩阵,得到含VSC-HVDC系统的数学模型.在该模型的基础上,考虑VSC内部电流环和系统控制要求,提出了一种新的VSC-HVDC控制策略.以一个含VSC HVDC的6机电力系统为例,仿真表明,采用该控制策略,在系统发生大扰动后,VSC HVDC不仅能够迅速恢复正常运行,而且对系统电压和频率稳定没有太大影响.
Directory of Open Access Journals (Sweden)
Eduardo Pérez Lobato
2006-08-01
Full Text Available This paper presents the use of a microcontroller to demodulate two Pulse Width Modulated (PWM signals which are being generated by a digital accelerometer, to obtain their pulse widths and transmit them serially to a parallel port of a general purpose computer.Esta publicación presenta el uso de un microcontrolador para demodular dos señales PWM que están siendo generadas por un acelerómetro digital, obtener sus anchos y enviarlas en forma serial al puerto paralelo de un computador de propósitos generales.
Modelling and Controller Design of Electro-Pneumatic Actuator Based on PWM
Directory of Open Access Journals (Sweden)
Behrouz Najjari
2012-07-01
Full Text Available In this paper, a nonlinear model associated to the fast switching on-off solenoid valve and pneumatic cylinder was dynamically presented. Furthermore, an investigation into the electrical, magnetic, mechanical and fluid subsystems are made. Two common control policies to track valve position, a Proportional Integrator (PI based on Pulse Width Modulation (PWM and hysteresis controllers, are investigated. To control cylinder position, a Programmable Logic Controller (PLC on a simulated unit and an experimental setup regulated with AVR microcontroller are carried out. Experimental results show effective validation to the simulation results from PLC.
Filtro paso bajo discreto de operación directa sobre señales PWM
López Batres, Sergio
2010-01-01
Este proyecto aborda la construcción y diseño de un filtro de paso bajo que opera sobre señales moduladas en anchura de impulsos (PWM). Utiliza componentes analógicos y un microprocesador que efectúa el control del sistema. Su función es servir de atenuador de los armónicos en amplificadores de clase D que podrían usarse en sistemas de audio, sin necesidad de un filtro paso bajo analógico de orden elevado. Ingeniería Técnica en Electrónica