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1

Performance Analysis of Three Phase PWM Voltage Source Inverter Fed Three Phase Induction Motor Drive  

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Full Text Available This paper deals with the performance analysis of three phase induction motor drive fed by a PWM voltage source inverter. The PWM method, which involves the modulation of conventional sinusoidal reference signal and a triangular carrier is used here to produce pulse width modulated output only for under modulation index. This paper work deals mainly with the performance analysis of three phase induction motor fed by PWM voltage source inverter in terms of phase current of inverter, rotor and stator current , speed ,electromagnetic torque developed and total harmonic distortion in line and phase voltage of inverter for under modulation range i.e. ma<1. For the implementation of the proposed drive the MATLAB/SIMLINK environment has been used. Two types of the switching techniques are available for the production of the balanced three phase output voltage i.e. either unipolar scheme or bipolar scheme but only unipolar scheme has been used as it offers several advantages. The performance of the inverter has been carried out by using the parameter total harmonic distortion. The impact of the modulation index on the performance of the inverter has been done in terms of the waveforms for inverter phase voltage, line voltage, line current, stator current, rotor current, rotor speed and electromagnetic torque developed by the motor

Amit Kumar Sharma

2013-03-01

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Control Strategy for Three Phase Voltage Source PWM Rectifier Based on the Space Vector Modulation  

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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 stab...

Hartani, K.; Miloud, Y.

2010-01-01

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A single leg switched PWM method for three-phase H-Bridge Voltage Source Converters  

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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-...

Senturk, Osman Selcuk; Helle, Lars; Munk-nielsen, Stig; Rodriguez, Pedro; Teodorescu, Remus

2009-01-01

4

A single leg switched PWM method for three-phase H-bridge voltage source converters  

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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-...

Senturk, Osman S.; Munk-nielsen, Stig; Teodorescu, Remus; Helle, Lars; Rodri?guez Corte?s, Pedro

2009-01-01

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Control Strategy for Three Phase Voltage Source PWM Rectifier Based on the Space Vector Modulation  

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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.

MILOUD, Y.

2010-08-01

6

A single leg switched PWM method for three-phase H-bridge voltage source converters  

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This paper proposes a single leg switched or a hybrid PWM (HPWM) method for three-phase three-level HBridge 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...

Senturk, Osman S.; Munk-nielsen, Stig; Teodorescu, Remus; Helle, Lars; Rodri?guez Corte?s, Pedro

2009-01-01

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Modeling and dynamic analysis of a fast response three-phase PWM voltage source rectifier  

Energy Technology Data Exchange (ETDEWEB)

The dynamic performance of a proposed three-phase PWM Voltage Source Rectifier-based AC/DC power supply system was studied, using a feedforward/feedback control algorithm. Small signal analysis is used to derive a linear model of the power supply in the s-domain. From this model, various transfer functions are derived to predict the behaviour of the system following step load, input AC line and DC bus voltage reference changes. The analysis is validated by time domain simulation. 6 refs., 2 tabs., 6 figs.

Dewan, S. B. [Toronto Univ., Dept. of Electrical and Computer Engineering, ON (Canada); Pande, M.

1998-11-01

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A single leg switched PWM method for three-phase H-Bridge Voltage Source Converters  

DEFF Research Database (Denmark)

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 is demonstrated by the simulations of a 6MW wind turbine's grid connection and experimentally verified via a smallscale prototype.

Senturk, Osman Selcuk; Helle, Lars

2009-01-01

9

High Performance FPGA Based Digital Space Vector PWM Three Phase Voltage Source Inverter  

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Full Text Available This paper focuses on the design of a low power and high performance FPGA based Digital Space Vector Pulse Width Modulation (DSVPWM controller for three phase voltage source inverter. A new method is proposed to realize easy, accurate and high performance DSVPWM technique based on FPGA with low resource consumption and reduced execution time than conventional methods. Equations of SVPWM are relatively complicated and need a considerable time to execute on a typical microcontroller, therefore a simple method is presented to minimize run time of instructions, e.g. the multiplication operation used in these equations is replaced by a proposed signed and unsigned shifter using 2 to 1 multiplexer unit. Total power consumption of controller is reduced to 37 mW at 100MHz clock frequency. The proposed DSVPWM technique algorithm was synthesized and implemented using Quartus II 9.1V and Cyclone II FPGA, to target device EP2C20F484C6. Also power is analyzed using XPower analyzer. Experimentation and results demonstrate that proposed method have high performance than other works.

Bahram Rashidi

2013-01-01

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An Active-Passive Capacitor-Commutated Converter for HVDC Systems with a Three-Phase Voltage-Source PWM Converter  

Science.gov (United States)

This paper introduces a new approach to the capacitor-commutated converters (CCCs) for HVDC systems. A small-rated three-phase voltage-source PWM converter is connected between a series commutation capacitor and thyristor converter through matching transformers. The PWM converter acts as auxiliary commutation-capacitor for the thyristor converter while the series passive capacitor acts as the main commutation capacitor. The capacitance, which is the sum of the small-rated active and series passive capacitors, is variable, so that stable commutation is obtained. In CCCs commutation failure occurs when the ac bus voltage is recovered whereas the proposed combined commutation-capacitor can achieve successful commutation for both rapidly decreasing and increasing ac bus voltages. The basic principle of the proposed active-passive capacitor commutated converter is discussed in detail. Then, constant margin-angle control with a constant firing angle of the thyristor converter is proposed using a function generator block. Digital simulation demonstrates the novelty and effectiveness of the proposed active-passive capacitor commutated converter.

Tanaka, Toshihiko; Funabiki, Shigeyuki; Nakazato, Masafumi

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Effective Improvement of DC Busline Voltage Utilization Factor in Two Switch-Auxiliary Quasi-Resonant DC Link Snubber Assisted Three Phase Voltage Source Type Soft-Switching PWM Inverter  

Science.gov (United States)

In recent years, a resonant snubber to minimize switching power losses and EMI noises have attracted special interest for the voltage-fed soft switching sinewave PWM inverters and active rectifiers. The authors have discussed the performance evaluations on lower noise and high efficiency for two switch auxiliary resonant DC link snubber assisted three-phase voltage-fed soft switching PWM inverter. It was proved that cost effective three phase soft switching inverter treated here is able to improve both efficiency and EMI noise. However, some practical problems to be improved have recognized for the soft-switching three phase PWM inverter treated here from a practical point of view. This three phase soft-switching inverter with two switch type auxiliary resonant DC link snubber has significant disadvantages of DC busline link voltage reduction for the existence of the zero voltage mode transition period as well as the larger size and physical volume of electrolytic capacitor incorporated into the resonant DC link snubber. The additional technology to minimize the busline DC link zero voltage period in order to overcome the practical problems mentioned above is newly proposed in this paper. From experimental and simulation viewpoints, the modified version of this soft-switching inverter is discussed and evaluated for the DC busline voltage utilization factor as compared with the previously developed one.

Nagai, Shinichiro; Sato, Shinji; Yamamoto, Masayoshi; Hiraki, Eiji; Nakaoka, Mutsuo

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XMEGA-Based Implementation of Four-Switch, Three-Phase Voltage Source Inverter-Fed Induction Motor Drive  

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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...

Abolfazl Halavei Niasar; Ehsan Boloor Kashani

2013-01-01

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Simulation Investigation of SPWM, THIPWM and SVPWM Techniques for Three Phase Voltage Source Inverter  

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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.

Zulkifilie Bin Ibrahim

2014-03-01

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A Comprehensive Study of Modulation Strategies for Three Phase Low Cost PWM Converter  

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Full Text Available A three phase voltage source converter using six power switches is a very important structure with wide variety of applications involving sophisticated ac drives, active power filters and power supplies etc. PWM voltage source inverters are also being incorporated in grid connected distributed power generating units to provide secure and reliable power to the utility grid. Due to the popularity of three-phase PWM converters there have been efforts in reducing the component count in these power electronic converters as a cost effective substitute. These researches led to the development of four-switch converter topology. The four switches present in thepower circuit can be controlled in various ways to deliver the desired characteristics of sinusoidal source current, ability to deliver unity or even leading power factor, bidirectional power flow. To obtain such characteristics of the converter, various control techniques have been envisaged and implemented. The other PWM strategies have their own advantages and disadvantages. In this paper a study of the various control methods applied to four-switch PWM converter is presented are presented along with their performancecomparison.

S. BHATTACHARYA

2011-07-01

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XMEGA-Based Implementation of Four-Switch, Three-Phase Voltage Source Inverter-Fed Induction Motor Drive  

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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.

Abolfazl Halavei Niasar

2013-02-01

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Reduced Snubber Circuit Elements For Pwm Voltage Source Inverter  

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This paper presents the description and simulation of a new proposed arrangement of RLD/RCD snubber circuit used with pulse width modulated voltage source inverter. The new arrangement allows minimizing the number of active elements of RCD with 50%. This will help the designer to reduce the size of the system. SPICE programming package is used as principal simulation tool. A detailed simulation given that includes the sever effects of snubber diode reverse recovery current, as well as, the ef...

Saied, Basil M.

2002-01-01

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A Novel PWM Scheme for a Three-Level Voltage Source Inverter Fed Induction Motor  

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This paper presents a space vector PWM scheme for a three level GTO voltage source inverter fed induction motor. This SVPWM method provides high safety voltages with less harmonic components compared to two level structures and reduces the switching losses by limiting the switching to the two thirds of the pulse duty cycle. The principle of SVPWM method and voltage vector selection procedure for two level and three level inverters are described in detail. The theoretical study was numerically...

Satish Kumar, P.; Amarnath, J.; Narasimham, S. V. L.

2009-01-01

18

Modulation Index Effect on the 5-Level SHE-PWM Voltage Source Inverter  

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Full Text Available Harmonic content of the voltage source inverters is important and must be in the allowed ranges. Different method are proposed to decrease the Total Harmonic Distortion (THD and caused to be sinusoidal the output voltage of inverters. One of these methods is using multilevel structure. In this structure many important parameters which are effective on voltage source inverter operation that among them we can mention to modulation index (MI. Variation of modulation index can change the THD. One of the harmonic reduction methods is using multilevel structure. In this paper, a sample 5-level SHE-PWM voltage source inverter is presented and all equation and choosing switching angles for elimination desired harmonics from different order. To investigate the effective parameters on the inverter operation, a typical 5-level inverter is simulated in PSPICE software. The simulation has been done for different values of modulation and its effect on the inverter operation is evaluated.

Hassan Feshki Farahani

2011-02-01

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Analysis of Peak-to-Peak Current Ripple Amplitude in Seven-Phase PWM Voltage Source Inverters  

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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 c...

Gabriele Grandi; Jelena Loncarski

2013-01-01

20

A Novel PWM Scheme for a Three-Level Voltage Source Inverter Fed Induction Motor  

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Full Text Available This paper presents a space vector PWM scheme for a three level GTO voltage source inverter fed induction motor. This SVPWM method provides high safety voltages with less harmonic components compared to two level structures and reduces the switching losses by limiting the switching to the two thirds of the pulse duty cycle. The principle of SVPWM method and voltage vector selection procedure for two level and three level inverters are described in detail. The theoretical study was numerically simulated and high power and high voltage three-level GTO inverters applied to induction motors drives.

J. Amarnath

2009-03-01

 
 
 
 
21

A new PWM algorithm for battery-source three-phase inverters  

Energy Technology Data Exchange (ETDEWEB)

A new PWM algorithm for battery-source three-phase inverters is described in this paper. The concept of the algorithm is to determine the pulsewidths by equating the areas of the segments of the sinusodial reference with the related output pulse areas. The algorithm is particularly suitable to handle a non-constant voltage source with good harmonic suppression. Since the pulsewidths are computable in real time with minimal storage requirement as well as compact hardware and software, it is especially suitable for single-chip microcomputer implementation. Experimental results show that the single-chip microcomputer Intel 8095-based battery-source inverter can control a 3 kW synchronous motor drive satisfactorily over a frequency range of 2 to 100Hz.

Chan, C.C. (Dept. of Electrical and Electronic Engineering, Univ. of Hong Kong, Pokfulam Road (HK)); Chau, K.T. (Dept. of Electrical Engineering, Hong Kong Polytechnic, Hung Hom (HK))

1991-01-01

22

Analysis of Discontinuous Space Vector PWM Techniques for a Seven-Phase Voltage Source Inverter  

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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.

Mohd. Arif Khan

2012-03-01

23

Simulation Study of the Carrier-Based PWM Method in Three- Phase Flying Capacitor Inverters  

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Full Text Available This paper is a simulation study ofmodulation strategies in three-phase flying capacitorinverters. Under investigation are those strategies thatsolve the capacitor voltage balancing problem: phaseshiftPWM method, the saw-tooth rotation PWM methodand carrier redistribution PWM method. The results areshown through simulation.

Adrian ?chiop

2008-05-01

24

Analysis on Photovoltaic Assisted Three Phase five level Unipolar PWM Inverter for Induction Motor Driven Water Pumping System  

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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

Ajay Kumar Maurya, Kishore Chahar, Y. K. Chauhan

2013-03-01

25

An improved design of virtual output impedance loop for droop-controlled parallel three-phase Voltage Source Inverters  

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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 virtual output impedance loop based on the decomposition of inverter output current is developed, where the positive- and negative-sequence virtual impedances are synthesized separately. Thus, the negat...

Wang, Xiongfei; Blaabjerg, Frede; Chen, Zhe

2012-01-01

26

Modeling, analysis, and design of stationary reference frame droop controlled parallel three-phase voltage source inverters  

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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 t...

Vasquez, Juan Carlos; Guerrero, Josep M.; Savaghebi, Mehdi; Eloy-garcia, Joaquin; Teodorescu, Remus

2012-01-01

27

Modeling, analysis, and design of stationary reference frame droop controlled parallel three-phase voltage source inverters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 of the VSIs were based on the stationary reference frame. A hierarchical control for the paralleled VSI system was developed based on three levels. The primary control includes the droop method and the ...

Vasquez, Juan Carlos; Guerrero, Josep M.; Savaghebi, Mehdi; Teodorescu, Remus

2011-01-01

28

Modeling, analysis, and design of stationary reference frame droop controlled parallel three-phase voltage source inverters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 t...

Vasquez, Juan Carlos; Guerrero, Josep M.; Savaghebi, Mehdi; Eloy-garcia, Joaquin; Teodorescu, Remus

2013-01-01

29

Determination of Rotational-Machine Characteristics by Performing DC Tests using Voltage-Source PWM Inverter  

Science.gov (United States)

The DC tests can predict the operational impedance of rotational machines by a simple standstill test. This paper presents a new DC test using a voltage-source PWM inverter, which does not require a specially assembled DC-power-source unit that is required to perform conventional DC tests. In this paper, three DC tests (DC decay, step response method, and pulse response methods) using the inverter as a power source are discussed. These tests are performed on an air-core reactor and 5.5kW semi-closed squirrel-cage induction machine to verify their validity. In addition, the authors propose an improved DC decay test that can consider the magnetic saturation of the main flux; this test is referred to as the two-step-voltage DC decay test. This test is also carried out on the tested induction machine. Using the test results, the authors demonstrate the calculation of not only no-load saturation performance by considering the magnetic saturation flux but also the starting performance. By comparing between these calculation results and actual measurement data, the authors validate the proposed two-step-voltage DC decay test.

Yamamoto, Shu; Oyama, Takashi; Ara, Takahiro

30

Quality Assessment of Soft-Switching Based Single-phase Pulse Width Modulated Voltage Source Inverter (PWM VSI)  

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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. T...

Jaffery, Z. A.; Sunil Kumar Chaudhary

2012-01-01

31

Power Electronic Transformer based Three-Phase PWM AC Drives  

Science.gov (United States)

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-mode voltage suppression at the load end, 3) High quality output voltage waveform (comparable to conventional space vector PWM modulated two level inverter) and 4) Minimization of output voltage loss, common-mode voltage switching and distortion of the load current waveform due to leakage inductance commutation. All of the proposed topologies along with the proposed control schemes have been analyzed and simulated in MATLABSimulink. A hardware prototype has been fabricated and tested. The simulation and experimental results verify the operation and advantages of the proposed topologies and their control.

Basu, Kaushik

32

Control Schemes for Auxiliary Switches of Three-Phase PWM Resonant Snubber Inverters  

Science.gov (United States)

Control schemes for auxiliary switches of PWM controlled three-phase resonant snubber inverters (RSIs) are proposed. The control schemes proposed in this paper are based on a conventional PWM technique. To avoid zero voltage switching lost conditions, the conventional PWM technique is modified in the proposed schemes. The proposed control schemes are so simple that they are suitable for digital control. In this paper, a CPLD (Complex Programmable Logic Device)-based control IC, which realizes the proposed control schemes, for three-phase auxiliary RSIs is also proposed and implemented. The IC generates gate-signals for main- and auxiliary-devices of the three-phase RSI based on the proposed control schemes. The effectiveness of the proposed control schemes were verified through the experiments. As the results, ZVS (Zero Voltage Switching) turn-on at the main devices was achieved and a smooth sinusoidal output current was obtained by use of the control IC.

Hoshi, Nobukazu; Oguchi, Kuniomi

33

Modeling and Simulation of a Carrier-based PWM Voltage Source Inverter for a Nine Phase Induction Machine Drive  

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Full Text Available The analysis of a carrier-based PWM two level voltage source inverter for a nine phase induction machine drive system is presented in this paper. Methods for generating zero-sequence signals during balanced and unbalanced condition are established. Simulation results for the analysis are presented. Two fault conditions involving the voltage source inverter and the nine-phase squirrel cage induction machine load are investigated. For the two fault scenarios considered, the effects on the performance characteristics of the induction machine load are highlighted. The simulation results obtained show that the two imbalance conditions considered result in substantial oscillations on the electromagnetic torque of the machine with attendant reduction in the torque rating. There is also large slip in the rotor speed.

Omonowo David Momoh

2014-07-01

34

Intelligent Optimize Design of LCL Filter for Three-Phase Voltage-Source PWM Rectifier  

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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 intel...

Sun, Wei; Chen, Zhe; Wu, Xiaojie

2009-01-01

35

A Novel Three-Phase UPS Inverter Driven by Error-Tracking-Mode PWM Scheme  

Science.gov (United States)

With prevalence of information technology into our modern society and advance of automation technology in modern production process, the UPS market is assumed to make sustainable expansion. Error-Tracking-Mode PWM scheme offers novel constantly-sampled current-regulated switching algorithm to voltage-source power converters. This paper proposes a UPS in which Error-Tracking-Mode PWM scheme is applied to the current minor loop. The upper voltage control loop (ac-AVR) is developed afresh, that makes best of the PWM attributes. The equivalent output impedance of the UPS is derived theoretically for not only small signal but also large signal operation, that value can be arbitrarily specified by the ac-AVR parameters. A 3 kVA experimental setup was designed and fabricated, which has demonstrated the theoretical characteristics satisfactorily. The paper discusses the experimental results in detail. The authors believe that the paper presents a clue to realize independent and autonomic operation of dispersed PWM converters.

Ohshima, Masaaki; Nakamura, Fuminori; Tamai, Shinzo; Yamamoto, Yuushin; Yoshida, Kouichi

36

A new mathematical model and control of a three-phase AC-DC voltage source converter  

Energy Technology Data Exchange (ETDEWEB)

A new mathematical model of the power circuit of a three-phase voltage source converter (VSC) was developed in the stationary and synchronous reference frames. The mathematical model was then used to analyze and synthesize the voltage and current control loops for the VSC. Analytical expressions were derived for calculating the gains and time constants of the current and voltage regulators. The mathematical model was used to control a 140-kW regenerative VSC. The synchronous reference frame model was used to define feedforward signals in the current regulators to eliminate the cross coupling between the d and q phases. It allowed the reduction of the current control loop to first-order plants and improved their tracking capability. The bandwidths of the current and voltage-control loops were found to be approximately 20 and 60 times (respectively) smaller than the sampling frequency. All control algorithms were implemented in a digital-signal processor. All results of the analysis were experimentally verified.

Blasko, V.; Kaura, V. [Rockwell Automation-Allen Bradley Co., Mequon, WI (United States). Standard Drives Div.

1997-01-01

37

Converter-flux-based current control of voltage source PWM rectifiers - analysis and implementation  

Energy Technology Data Exchange (ETDEWEB)

Pulsewidth-modulated (PWM) rectifier technology is increasingly used in industrial applications like variable-speed motor drives, since it offers several desired features such as sinusoidal input currents, controllable power factor, bidirectional power flow and high quality DC output voltage. To achieve these features, however, an effective control system with fast and accurate current and DC voltage responses is required. From various control strategies proposed to meet these control objectives, in most cases the commonly known principle of the synchronous-frame current vector control along with some space-vector PWM scheme have been applied. Recently, however, new control approaches analogous to the well-established direct torque control (DTC) method for electrical machines have also emerged to implement a high-performance PWM rectifier. In this thesis the concepts of classical synchronous-frame current control and DTC-based PWM rectifier control are combined and a new converter-flux-based current control (CFCC) scheme is introduced. To achieve sufficient dynamic performance and to ensure a stable operation, the proposed control system is thoroughly analysed and simple rules for the controller design are suggested. Special attention is paid to the estimation of the converter flux, which is the key element of converter-flux-based control. Discrete-time implementation is also discussed. Line-voltage-sensorless reactive reactive power control methods for the L- and LCL-type line filters are presented. For the L-filter an open-loop control law for the d-axis current reference is proposed. In the case of the LCL-filter the combined open-loop control and feedback control is proposed. The influence of the erroneous filter parameter estimates on the accuracy of the developed control schemes is also discussed. A new zero vector selection rule for suppressing the zero-sequence current in parallel-connected PWM rectifiers is proposed. With this method a truly standalone and independent control of the converter units is allowed and traditional transformer isolation and synchronised-control-based solutions are avoided. The implementation requires only one additional current sensor. The proposed schemes are evaluated by the simulations and laboratory experiments. A satisfactory performance and good agreement between the theory and practice are demonstrated. (orig.)

Poellaenen, R.

2003-07-01

38

Space Vector PWM Signal Generation for a Three Phase Inverter and Hardware Implementation Using µ- Controller  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents the space vector definitions for the flux, current and the voltage in a three phase system. In this paper, a Space Vector PWM signal generation for a conventional 3-phase inverter by comparing the reference phase voltages with the reference voltage vector is presented. The sector in which the tip of the reference vector lies is found out and the proposed Space Vector-PWM (SVPWM method generates the inverter leg switching times, from the sampled reference phase voltage amplitudes in a sampling interval. Here Vdc is the conventional three phase inverter DC link voltage. To generate gating signals PIC ?- controller is used in addition to the interface circuit. The present work explains the gating signal generation and implementation by SVPWM using ?- controller.

B. Muralidhara,

2010-10-01

39

A Microcomputer-Based Predictive Digital Current Programmed Control System for Three-phase PWM Rectifier  

Directory of Open Access Journals (Sweden)

Full Text Available The paper describes a microcomputer control system, which uses the floating-point digital signal processor TMS320LF2407 from Texas Instruments, for three-phase PWM rectifier.  It could effectively eliminate harmonic distortion of line currents and provides power factor correction. Moreover, it can be save electrical energy and reduction of production cost. In the control system, the predictive current control in two-dimensional (?-? stationary frame, makes the input current following the phase voltage in phase to get unity power factor; and space vector pulse wide modulation (SVPWM generates the modulation wave. Finally, the three-phase PWM rectifier using the proposed control system is designed in Simulink/Matlab and executed in laboratory prototype, and the results are provided to verify the proposed control system in the end of the paper.

Ninghui Wang

2011-08-01

40

Research on Three-phase Voltage Type PWM Rectifier System Based on SVPWM Control  

Directory of Open Access Journals (Sweden)

Full Text Available The fundamental principle of SVPWM is introduced in this study. The design on the structure of three-phase voltage type PWM rectifier system based on SVPWM control was also discussed. Then we calculate the DC capacitor and AC side inductance. The computer simulation tool MATLAB/Simulink is taken and the result is shown in the end. The result indicates that the design of such platform is feasible.

Haoran Shi

2013-04-01

 
 
 
 
41

Microcontroller based PWM controlled four switch three phase inverter fed induction motor drive  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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. S...

Mohanty Kant Nalin; Muthu Ranganath

2010-01-01

42

Comparative Analysis of PWM Techniques for Three Level Diode Clamped Voltage Source Inverter  

Directory of Open Access Journals (Sweden)

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.

Zulkifilie Bin Ibrahim

2014-07-01

43

Comparative analysis of SPWM and SVPWM control for three phase inverter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A voltage source inverter is commonly used to supply a three-phase induction motor with variable frequency and variable voltage for variable speed applications. A suitable pulse width modulation (PWM) technique is employed to obtain the required output voltage in the line side of the inverter. The different methods for PWM generation can be broadly classified into triangle comparison based PWM (TCPWM) and Space Vector based PWM (SVPWM). In TCPWM methods such as sine-triangle PWM, three phase ...

2010-01-01

44

A New PWM Modifying Technique for Reconstructing Three-phase Currents from DC Bus Current  

Science.gov (United States)

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.

Aoyagi, Shigehisa; Iwaji, Yoshitaka; Tobari, Kazuaki; Sakamoto, Kiyoshi

45

Microcontroller based PWM Inverter for Speed Control of a Three Phase Induction Motor  

Directory of Open Access Journals (Sweden)

Full Text Available Three phase induction motor has proven to be an extremely reliable electromechanical energy conversion device for over 100 years. The speed control of induction motor is a crying need for the real world industrial applications. However, there are so many options available for the precise speed control of induction motor except by changingthe frequency. Therefore to achieve the goal of speed control of induction motor, there is no alternative of inverters. With the availability of high speed power semiconductor devices, the three phase inverters play the key role for variable speed ac motor drives. In addition to the speed control, the inverter can also provide some unique features, like voltage control, torque control, power factor correction, auto breaking, built in protection system and so forth.In this paper, a three phases PWM inverter using MC3PHAC microcontroller with computer interface is proposed to run a squirrel case induction motor. Some results of the proposed inverter are presented.

M. A. Latif

2013-04-01

46

Microcontroller based PWM controlled four switch three phase inverter fed induction motor drive  

Directory of Open Access Journals (Sweden)

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.

Mohanty Kant Nalin

2010-01-01

47

Efficiency Analysis of PWM Inverter Fed Three-Phase and Dual Three-Phase High Frequency Induction Machines for Low/Medium Power Applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A performance analysis of three-phase and dual three-phase (DTP) induction pulsewidth modulation (PWM) inverter-fed motor drives is conducted in this paper. The focus is on the efficiency performance of high-frequency DTP machines compared to their three-phase counterparts in low/medium power applications. For this purpose, a DTP machine, having two sets of stator three-phase windings spatially shifted by 30 electrical degrees (asymmetrical six-phase winding configuration), was tested for bot...

2008-01-01

48

Three phase six-switch PWM buck rectifier with power factor improvement  

International Nuclear Information System (INIS)

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 is presented which operates at nearly unity power factor and provides variable output voltage. Small size energy storing components are required depending upon switching frequency. MATLAB simulation is performed and modified Sinusoidal Pulse Width Modulation (SPWM) switching technique is used in 3kW prototype converter to demonstrate low input current THD, nearly unity displacement factor, well regulated output voltage and reduced switching losses compared to conventional SPWM.

2013-06-10

49

A Passive EMI Filter with Access to the Ungrounded Motor Neutral Line-The Case that a General-Purpose Inverter is Directly Connected to a Three-Phase Grounded Voltage Source-  

Science.gov (United States)

This paper proposes a small-sized passive EMI filter for the purpose of eliminating high-frequency shaft voltage and ground leakage current from an ac motor. The motor is driven by a general-purpose PWM inverter connected to a three-phase grounded voltage source. The passive EMI filter requires access to the ungrounded neutral point of the motor. This unique circuit configuration makes the common-mode inductor effective in reducing the high-frequency common-mode voltage generated by the PWM inverter with a carrier frequency of 15kHz. As a result, both high-frequency shaft voltage and ground leakage current can be eliminated very efficiently. However, the common-mode inductor may not play any role in reducing the low-frequency common-mode voltage generated by the diode rectifier, so that a low-frequency component still remains in the shaft voltage. Such a low-frequency shaft voltage may not produce any bad effect on motor bearings. The validity and effectiveness of the EMI filter is verified by experimental results obtained from a 200-V 5-kVA laboratory system.

Doumoto, Takafumi; Akagi, Hirofumi

50

Design and Digital Implementation of Constant Frequency Hysteresis Current Controller for Three-Phase Voltage Source Inverter Using TMS320F2812  

Science.gov (United States)

A constant frequency hysteresis current control technique for a three-phase voltage source inverter (VSI) has been developed for AC drives, power quality and renewable energy applications. This paper presents a digital implementation of a constant frequency hysteresis current control technique for a three-phase VSI feeding an inductive load, using digital signal controller TMS320F2812. The limitations of variable frequency hysteresis control have been discussed and overcoming these limitations by means of digital implementation has been proposed. The complete design procedure of the proposed technique has been presented with an illustrative example. The three-phase VSI feeding an inductive load has also been simulated by using MATLAB and the simulation results have been presented. The hardware results of hysteresis current controlled three-phase VSI feeding an inductive load have been presented. Also the performance analysis of the hysteresis current controller has been presented. Operation of this controller has also been explained with a help of phase plane trajectory of hysteresis controller.

Kalyanraj, D.; Lenin Prakash, S.

2014-01-01

51

EXPERIMENTAL ANALYSIS OF TOTAL HARMONIC DISTORTION BY APPLYING VARIOUS PWM TECHNIQUES ON THREE PHASE SQUIRREL CAGE MOTOR  

Directory of Open Access Journals (Sweden)

Full Text Available It has been found that by using Pulse with modulation technique can greatly reduce the harmonics distortions generated by the PV inverter. Harmonics reduction is the main consideration in three phase squirrel cage induction motor. We can improve the performance of the three phase squirrel cage Induction motor by the reduction of THD. In this research work, the harmonic distortion of the three phase induction motor was measured in terms of THD by Simulation model and the results of the Multiple Pulse With Modulation and Sinusoidal Pulse With Modulation inputs were compared to discover the lowest THD value. By using the PWM technique on the Three Phase Induction motor there was reduction in the VTHD by 6.98% and CTHD by 3.12% which in turn reduces the iron, winding and stray losses occurred in three phase squirrel cage induction motor.

P.Manikandan

2014-02-01

52

Current control methods for grid-side three-phase PWM voltage-source inverter in distributed generation systems  

DEFF Research Database (Denmark)

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.

Lar, Ionut Andrei; Radulescu, Mircea

2012-01-01

53

Single-carrier sinusoidal PWM-equivalent selective harmonic elimination for a five-level voltage source converter  

Energy Technology Data Exchange (ETDEWEB)

The paper presents a new variation of selective harmonic elimination pulse-width modulation (SHE-PWM) technique suitable for a high-power five-level converter used in constant frequency utility applications. The governing system of equations associated with the elimination of specific harmonics is defined based on an equal number of switching transitions when compared against the single-carrier sinusoidal PWM (SC-SPWM) technique. For this paper, it is assumed that the modulating signal (triangular carrier) of the equivalent SC-SPWM method has twenty per unit frequency. The switching transitions for every quarter period are therefore distributed between the converter levels according to the modulation index of SC-SPWM. It is confirmed that the proposed technique offers significantly higher converter bandwidth and higher dc bus utilization for the same switching transitions. Furthermore, the proposed SHE-PWM offers better harmonic performance compared to its SC-SPWM counterpart. Selected solutions for the switching transitions are presented and verified experimentally in order to confirm the effectiveness of the proposed technique. (author)

Dahidah, Mohamed S.A. [School of Electrical and Electronic Engineering, The University of Nottingham, Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor (Malaysia); Agelidis, Vassilios G. [School of Electrical and Information Engineering, The University of Sydney, NSW (Australia)

2008-11-15

54

Voltage source PWM rectifier-inverter with feed-forward control of instantaneous power. Shunji denryoku no feed forward seigyo wo fukashita den prime atsugata PWM seiryukiter dot inverter  

Energy Technology Data Exchange (ETDEWEB)

The voltage source PWM rectifier-inverter with feed-forward control of instantaneous power was proposed. The instantaneous power calculated on the control circuit of the PWM inverter was fed forward into the DC capacitor voltage control circuit of the PWM rectifier, and it made a great contribution to suppress voltage fluctuation of the DC capacitor in transient states. As the influence of detection delay of the instantaneous power on suppression of the voltage fluctuation was examined in the case of a DC capacitor of 90 {mu} F (200 V in DC voltage), the detection delay of nearly 0.1 ms in stepwise load change by 2 kW resulted in the capacitor voltage fluctuation of nearly {plus minus} 5%, and smaller detection delays were thus effective in suppressing the voltage fluctuation. Experiments carried out under rapid change in speed and load using a 3 kVA prototype system with a 1.5 kW PM motor as a load gave desirable performance. 6 refs., 16 figs.

Ogasawara, S.; Yamagishi, N.; Totsuka, H.; Akagi, H. (Nagaoka University of Technology, Niigata (Japan))

1991-11-20

55

Newly-Proposed Hybrid Resonant Commutaion Bridge Leg Link Snubber-Assisted Three-Phase ZVZCS-PWM Soft-Switching Inverter.  

Science.gov (United States)

This paper presents the newly-proposed hybrid resonant commutation bridge leg link (HRCB) snubber circuit which can achieve zero voltage and zero current soft-switching commutation for single-phase and three-phase voltage source-type inverter, along with its unique features and operation principle. The circuit parameter design approach for the HRCB snubber circuit and the determination estimating scheme of the gate pulse timing processing which is more suitable and acceptable for single-phase and space voltage vector modulated three-phase voltage source inverter using the HRCB snubber circuit are described in this paper. In particular the three-phase voltage source soft-switching inverter associated with the proposed HRCB circuits are evaluated and discussed from simulation and experimental viewpoint. The practical effectiveness of the HRCB snubber-assisted three-phase voltage source soft-switching inverter using IGBT power modules which is based on the instantaneous space voltage vector modulation is clarified on the output voltage waveform, actual efficiency and electromagnetic noises in comparison with three-phase voltage source-type conventional hard-switching inverter.

Hiraki, Eiji; Yoshida, Masanobu; Hirota, Yoshihiko; Nakaoka, Mutsuo

56

PWM Technique of Five-Leg Inverter Applying Two-Arm Modulation  

Science.gov (United States)

This paper presents the simple pulse width modulation (PWM) technique of a five-leg inverter to drive two three-phase AC motors independently. Normal PWM techniques in three-phase voltage source inverter cannot be used for the five-leg inverter with the independent drive. In this paper, two kinds of simple and novel PWM techniques of the five-leg inverter with two three-phase AC motors are introduced. Experimental results are provided to illustrate the validity of the proposed PWM technique.

Oka, Kazuo; Matsuse, Kouki

57

Comparative analysis of SPWM and SVPWM control for three phase inverter  

Directory of Open Access Journals (Sweden)

Full Text Available A voltage source inverter is commonly used to supply a three-phase induction motor with variable frequency and variable voltage for variable speed applications. A suitable pulse width modulation (PWM technique is employed to obtain the required output voltage in the line side of the inverter. The different methods for PWM generation can be broadly classified into triangle comparison based PWM (TCPWM and Space Vector based PWM (SVPWM. In TCPWM methods such as sine-triangle PWM, three phase reference modulating signals are compared against a common triangular carrier to generate the PWM signals for the three phases. In SVPWM methods, a revolving reference voltage vector is provided as voltage reference instead of three phase modulating waves. The magnitude and frequency of the fundamental component in the line side are controlled by the magnitude and frequency, respectively, of the reference vector. The highest possible peak phase fundamental is very less in sine triangle PWM when compared with space vector PWM. Space Vector Modulation (SVM technique has become the important PWM technique for three phase voltage source inverters for the control of AC Induction, Brushless DC, Switched Reluctance and Permanent Magnet Synchronous Motors. The study of space vector modulation technique reveals that space vector modulation technique utilizes DC bus voltage more efficiently and generates less harmonic distortion when compared with Sinusoidal PWM (SPWM technique. In this paper first a model for Space vector PWM is made and simulated using MATLAB/SIMULINK software and its performance is compared with Sinusoidal PWM. The simulation study reveals that Space vector PWM utilizes DC bus voltage more effectively and generates less THD when compared with sine PWM.

K. Vinoth Kumar

2010-07-01

58

Single-phase Utility Interaction System with Photovoltaic Generation for Three-phase PWM Current Source Inverter-Induction Motor Drives  

Science.gov (United States)

This paper presents a three-phase PWM current source inverter-induction motor drive system with photovoltaic generation. The system is interacted to single-phase utility using PWM converter, and the photovoltaic arrays are connected to the dc link of the system by employing a step-down chopper. The chopper is operated on PWM switching, and contributes to maintain the maximum power of the arrays and to smooth the dc link current in the small dc reactor. The PWM converter can flow the power in bidirection between the system and the utility with a sinusoidal current in the ac side. In this paper, the system configuration and the control methods are shown. First of all, the PWM strategy of the chopper, which depends on the converter PWM operation, is explained in detail and the switching patterns are given. Next, the experimental and the theoretical results at the steady state operations are given, and it is shown that the use of the PWM chopper is effective for the improvement of the ac waveforms. Finally, the waveforms at the transient operation are given in the variable speed drive of the motor and the change of the sunlight quantity for the arrays. The results prove that the proposed system has good performances for the utilization of the photovoltaic power.

Neba, Yasuhiko; Esaki, Tomokazu

59

Sine Carrier for Fundamental Fortification in Three Phase Z-Source PWM Inverters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper deals with a novel natural sampled pulse width modulation strategy for three phase Z-source inverter through carrier modification. The proposed sine carrier method, which uses the conventional sinusoidal reference signal and a sine carrier, has a better harmonic spectrum and a higher funda...

Shajith Ali

2009-01-01

60

Operation of a voltage source converter at increased utility voltage  

Energy Technology Data Exchange (ETDEWEB)

The operation of a voltage source converter (VSC) with regeneration capability, controllable power factor, and low distortion of utility currents is analyzed at increased utility voltage. Increase in the utility voltage causes a VSC to saturate and enter a nonlinear mode of operation. To operate under elevated utility, two steps are taken: (1) a pulse width modulation (PWM) algorithm is implemented which extends the linear region of operation by 15% and (2) a PWM saturation regulator is used to control the reactive current at higher utility voltages. The PWM algorithm reduces the switching losses by at least 33% and the effect of blanking time by one-third. All analytical results are experimentally verified on a 100 kW three-phase VSC.

Kaura, V.; Blasko, V. [Rockwell Automation-Allen Bradley Co., Mequon, WI (United States). Standard Drives Div.

1997-01-01

 
 
 
 
61

Open switch faults detection and localization algorithm for three phases shunt active power filter based on two level voltage source inverter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An open switch faults detection and localization algorithm for shunt three phase active filter topology is proposed. It mainly details converter configuration and examines a simple and reliable optimised fault diagnosis method. The converter topology is based on classical three-leg active power filter topology. A new fault diagnosis method is proposed, based on classical currents measurements. It includes combinatory logic to analyse and validate error signals. A Hysteresis Control is applied...

Benslimane, T.

2007-01-01

62

A Method for Calculating AC Currents from Sampled DC Current Data in a Three-phase PWM Inverter  

Science.gov (United States)

In order to reduce costs of inverters for home electrical appliances using the PMSM, the AC current sensor-less control is required as well as the position sensor-less control. This paper proposes a PWM technique suitable for calculating AC currents from sampled DC current data in the one-shunt system, which is one of the AC current sensor-less methods. The proposed PWM technique using a triangle carrier wave leads to the dc current sampling at near the top and bottom of the carrier wave, and AC current calculation within one cycle of the carrier under normal conditions. To reduce errors in the AC current calculation caused by the PWM current ripple, the current ripple waveforms are calculated from the instantaneous inverter output voltages and used for the compensation. The principles of the PWM technique and the AC current calculation are explained, as well as experimental results.

Fukumoto, Tetsuya; Watanabe, Yukie; Hamane, Hiroto; Hayashi, Yoichi

63

The chording effect on core losses of three-phase induction motor under sinusoidal and PWM voltage supplies  

Science.gov (United States)

The core losses and the lower-order voltage harmonics of four different chorded motors fed from sinusoidal supply and inverter voltage supply were invigilated at no-load condition. All the four motors were tested with 4, 8 and 16 kHz switching frequencies and 30, 40, 50 and 60 Hz modulation frequencies The motor with 120° coil pitch has the least core losses and the lower-order voltage harmonics under sinusoidal and pulse width modulation (PWM) voltage supplies at all switching and modulation frequencies. The drop in the core losses for this motor was 46% and 53% under sinusoidal and PWM voltage supplies, respectively. The motor with 120° coil pitch is recommended to be used under sinusoidal and PWM voltage supplies.

Deshmukh, Ram; Moses, A. J.; Anayi, F.

64

The chording effect on core losses of three-phase induction motor under sinusoidal and PWM voltage supplies  

International Nuclear Information System (INIS)

The core losses and the lower-order voltage harmonics of four different chorded motors fed from sinusoidal supply and inverter voltage supply were invigilated at no-load condition. All the four motors were tested with 4, 8 and 16 kHz switching frequencies and 30, 40, 50 and 60 Hz modulation frequencies The motor with 120 deg. coil pitch has the least core losses and the lower-order voltage harmonics under sinusoidal and pulse width modulation (PWM) voltage supplies at all switching and modulation frequencies. The drop in the core losses for this motor was 46% and 53% under sinusoidal and PWM voltage supplies, respectively. The motor with 120 deg. coil pitch is recommended to be used under sinusoidal and PWM voltage supplies

2008-10-01

65

The chording effect on core losses of three-phase induction motor under sinusoidal and PWM voltage supplies  

Energy Technology Data Exchange (ETDEWEB)

The core losses and the lower-order voltage harmonics of four different chorded motors fed from sinusoidal supply and inverter voltage supply were invigilated at no-load condition. All the four motors were tested with 4, 8 and 16 kHz switching frequencies and 30, 40, 50 and 60 Hz modulation frequencies The motor with 120 deg. coil pitch has the least core losses and the lower-order voltage harmonics under sinusoidal and pulse width modulation (PWM) voltage supplies at all switching and modulation frequencies. The drop in the core losses for this motor was 46% and 53% under sinusoidal and PWM voltage supplies, respectively. The motor with 120 deg. coil pitch is recommended to be used under sinusoidal and PWM voltage supplies.

Deshmukh, Ram; Moses, A.J. [Wolfson Centre for Magnetics, Cardiff School of Engineering, Queens Building, Newport Road, Cardiff, CF24 3AA Wales (United Kingdom); Anayi, F. [Wolfson Centre for Magnetics, Cardiff School of Engineering, Queens Building, Newport Road, Cardiff, CF24 3AA Wales (United Kingdom)], E-mail: spefja@cardiff.ac.uk

2008-10-15

66

Optimum space vector PWM algorithm for three-level inverter  

Directory of Open Access Journals (Sweden)

Full Text Available A Three - Level Voltage Source Inverter is used increasingly to supply a variable frequency and variable voltage for variable speed applications. A suitable pulse width modulation (PWM technique is employed to obtain the required output voltage at the line side of the inverter. This paper studies popular multi-level topology, Diode Clamped or Neutral Point Clamped for three-level. Two methods of Sine-triangle (SPWM and two methods of Space Vector Pulse Width Modulation (SVPWM are employed to generate the modulation wave. These modulation waves are compared against a triangular carrier to generate the PWM signals for the three phases. In SVPWM methods, a revolving reference voltage vector is provided as voltage reference instead of three phase modulating waves used in SPWM. The magnitude and frequency of the fundamental component in the line side are controlled by the magnitude and frequency, respectively, of the reference vector. Space Vector Modulation Technique has become the important PWM technique for three phase Voltage Source Inverters because of its increased dc bus utilization and reduced harmonic distortion compared to SPWM. The four PWM methods are simulated in MATLAB/SIMULINK software and are compared for THD and Capacitor Balance. Programs are carried out using Embedded Editor functions and matlab editor functions. The simulation study reveals that Space vector PWM utilizes dc bus voltage more effectively, generates less THD and improved capacitor balance when compared to sine PWM.

B. Urmila

2011-09-01

67

Design and implementation of high performance direct power control of three-phase PWM rectifier, via fuzzy and PI controller for output voltage regulation  

International Nuclear Information System (INIS)

This paper proposes direct power control (DPC) for three-phase PWM rectifiers using a new switching table, without line voltage sensors. 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 main goal of the control system is to maintain the dc-bus voltage at the required level, while input currents drawn from the power supply should be sinusoidal and in phase with respective phase voltages to satisfy the unity power factor (UPF) operation. Conventional PI and a designed fuzzy logic-based controller, in the dc-bus voltage control loop, have been used to provide active power command. A dSPACE based experimental system was developed to verify the validity of the proposed DPC. The steady-state, and dynamic results illustrating the operation and performance of the proposed control scheme are presented. As a result, it was confirmed that the novel DPC is much better than the classical one. Line currents very close to sinusoidal waveforms (THD < 2%) and good regulation of dc-bus voltage are achieved using PI or fuzzy controller. Moreover, fuzzy logic controller gives excellent performance in transient state, a good rejection of impact load disturbance, and a good robustness

2009-01-01

68

Dual-Three Phase Induction Machine Drives Control—A Survey  

Science.gov (United States)

The paper aims to perform an overview on the state-of-the-art in the control of multi-phase drives employing dual-three phase induction machines. In particular, the paper is focused on modeling aspects, Pulse-Width Modulation (PWM) techniques for Voltage Source Inverters (VSI), Field Oriented Control (FOC) and Direct Torque Control (DTC) strategies for dual-three phase induction machines. Furthermore, the paper briefly presents the advantages of dual-three phase induction motor drives over the conventional three-phase drives and the different applications reported in the literature.

Bojoi, Radu; Farina, Francesco; Profumo, Francesco; Tenconi, Alberto

69

Feedforward Synchronised PWM for Adjustable Speed AC Drives with Different Control Modes  

DEFF Research Database (Denmark)

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, with vector approached for determination of the pulse patterns, with vector approach for determination of the pulse patterns. Different control modes of the drive system with synchronised PWM, including standard scalar V/F control, and also V2/F = constant and V/F2 = constant control regimes, have been analysed in the paper. Simulations give the behaviour of the PWM techniques proposed. Both continuous and discontinuous schemes of synchronised PWM, applied for the corresponding control regime, have been analysed and compared.

Oleschuk, Valentin; Blaabjerg, Frede

2002-01-01

70

THREE-PHASE ACTIVE POWER FILTER CONTROLLER FOR BALANCED AND UNBALANCED NON-LINEAR LOAD  

Directory of Open Access Journals (Sweden)

Full Text Available The active power filter produces equal but opposite harmonic currents to the point of connection with the nonlinear load. This results in a reduction of the original distortion and correction of the power factor. A threephase insulated gate bipolar transistor based current controlled voltage source inverter with a dc bus capacitor is used as an active filter. The firing pulses to the shunt active filter will be generated by using sine PWM method. The models for three-phase active power filter controller for balanced and unbalanced non-linear load is made and is simulated using Matlab/simulink software.

G.NAGESWARA RAO

2010-09-01

71

Space Vector Pulse Width Modulation Scheme for a Seven-Phase Voltage Source Inverter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Mohd. Arif Khan; Atif Iqbal; Sk Moin Ahmad

2011-01-01

72

Small-Signal Analysis of Single-Phase and Three-phase DC/AC and AC/DC PWM Converters with the Frequency-Shift Technique  

DEFF Research Database (Denmark)

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 is to minimize the input admittance in order to make the grid converter more robust to grid disturbance.

Blaabjerg, Frede; Aquila, A. DellÂ?

2004-01-01

73

Método experimental para determinação das capacitancias parasitas do motor de indução trifásico acionado por inversor MLP Experimental method for determining the parasitic capacitances of three-phase induction motor driven by PWM inverter  

Directory of Open Access Journals (Sweden)

Full Text Available A proposta deste trabalho é apresentar uma nova metodologia para determinação experimental das capacitancias parasitas do motor de indução trifásico de rotor em gaiola. As capacitancias parasitas fazem parte do circuito equivalente do motor para estudos de interferência eletromagnética causada no motor de indução em modo comum quando ele for acionado por inversor controlado por modulação por largura de pulsos (MLP. Os procedimentos propostos para o desenvolvimento deste novo método consistem em: a determinação dos parâmetros do circuito equivalente do motor de indução trifásico, em regime permanente, através de ensaio em laboratório; b estabelecer configurações de ligações entre o inversor MLP e o motor para medições das grandezas de interesse que são as seguintes: tensões de modo comum e de eixo, correntes de fuga e de eixo, através de circuito de medição desenvolvido para este fim; c calcular os valores das capacitancias parasitas entre estator e carcaça do motor; estator e rotor; rotor e carcaça e de rolamento utilizando a expressão matemática da definição de capacitancia; d utilizar o software Pspice para simular o sistema motor de indução trifásico, alimentado por inversor MLP, com os circuitos equivalentes em baixas e altas frequências; e obter as formas de onda características do fenômeno de modo comum.Three-phase induction motors present stray capacitances. The aim of this paper is to present a new methodology to experimentally determine these capacitances and also evaluates the effects of electromagnetic interference on the motors in common mode. The proposed procedures to the development of this new methodology consists in: a identification of the motor equivalent electrical circuit parameters through characteristic tests performed in the laboratory; b to set up configurations between PWM inverter and the motor for voltage and current measurements: common mode and shaft voltages, leakage and shaft (bearing currents by using a dedicated measuring circuit; c to calculate the parasitic capacitance values between stator and frame, stator and rotor, rotor and frame and bearings of the motor using the capacitance characteristic equation; d use the dedicated software Pspice to simulate the system composed by the three-phase induction motor fed by PWM inverter with the equivalent electrical circuit parameters; e to determine the characteristic waveforms involved in the common mode phenomenon.

Rudolf Ribeiro Riehl

2012-04-01

74

Método experimental para determinação das capacitancias parasitas do motor de indução trifásico acionado por inversor MLP / Experimental method for determining the parasitic capacitances of three-phase induction motor driven by PWM inverter  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A proposta deste trabalho é apresentar uma nova metodologia para determinação experimental das capacitancias parasitas do motor de indução trifásico de rotor em gaiola. As capacitancias parasitas fazem parte do circuito equivalente do motor para estudos de interferência eletromagnética causada no mo [...] tor de indução em modo comum quando ele for acionado por inversor controlado por modulação por largura de pulsos (MLP). Os procedimentos propostos para o desenvolvimento deste novo método consistem em: a) determinação dos parâmetros do circuito equivalente do motor de indução trifásico, em regime permanente, através de ensaio em laboratório; b) estabelecer configurações de ligações entre o inversor MLP e o motor para medições das grandezas de interesse que são as seguintes: tensões de modo comum e de eixo, correntes de fuga e de eixo, através de circuito de medição desenvolvido para este fim; c) calcular os valores das capacitancias parasitas entre estator e carcaça do motor; estator e rotor; rotor e carcaça e de rolamento utilizando a expressão matemática da definição de capacitancia; d) utilizar o software Pspice para simular o sistema motor de indução trifásico, alimentado por inversor MLP, com os circuitos equivalentes em baixas e altas frequências; e) obter as formas de onda características do fenômeno de modo comum. Abstract in english Three-phase induction motors present stray capacitances. The aim of this paper is to present a new methodology to experimentally determine these capacitances and also evaluates the effects of electromagnetic interference on the motors in common mode. The proposed procedures to the development of thi [...] s new methodology consists in: a) identification of the motor equivalent electrical circuit parameters through characteristic tests performed in the laboratory; b) to set up configurations between PWM inverter and the motor for voltage and current measurements: common mode and shaft voltages, leakage and shaft (bearing) currents by using a dedicated measuring circuit; c) to calculate the parasitic capacitance values between stator and frame, stator and rotor, rotor and frame and bearings of the motor using the capacitance characteristic equation; d) use the dedicated software Pspice to simulate the system composed by the three-phase induction motor fed by PWM inverter with the equivalent electrical circuit parameters; e) to determine the characteristic waveforms involved in the common mode phenomenon.

Rudolf Ribeiro, Riehl; Ernesto, Ruppert.

75

FPGA Based Three Phase Multilevel PWM Inverter  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents, a phase shifted carrier pulse width modulation is proposed, which can minimize the output total harmonic distortion and enhances the output voltages from five level inverter to multilevel topologies. Multilevel inverters are important for power electronics applications such as flexible AC transmission systems, renewable energy sources, unin terruptible power supplies and active power filters. Two novel methodologies adopting the phase shifted carrier pulse width modulation concept are proposed in this paper. The phase shifted carrier pulse width modulation cascaded multilevel inverter strategy minimized output total harmonic distortion and phase shifted carrier switching frequency optimal pulse width modulation cascaded multilevel inverters strategy enhances the output voltages. Field programmable gate array has been chosen to implement the pulse width modulation due its fast proto typing, simple hardware and software design. Simulation and Experimental results are provided.

Tamboli J. I.

2014-04-01

76

DSC-like control of voltage-source pwm rectifier.  

Czech Academy of Sciences Publication Activity Database

. Košice : Technical University, 1996. - (80-967249-3-2. 1).[International Conference on Electrical Drives and Power Electronics. Stará Lesná (SK), 01.10.1996-03.10.1996]Grant CEP: GA ?R GA102/94/1360

Valouch, Viktor; Škramlík, Ji?í

77

Space Vector Pulse Width Modulation Scheme for a Seven-Phase Voltage Source Inverter  

Directory of Open Access Journals (Sweden)

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

Mohd. Arif Khan

2011-09-01

78

Starting Phenomena and Temperature-rise under vvvf Supply of Three-Phase Squirrel-Cage ac Traction Motor of Electric Locomotive  

Science.gov (United States)

In three-phase squirrel-cage ac traction motor, temperature-rise calculation during variable-voltage and variable-frequency starting is of vital importance and has to be predicted and critically examined. Under voltage source inverter supply with PWM, the generation of harmonics by inverter supply reduces the output during starting due to higher harmonic losses, thereby reducing the starting tractive effort in kN on locomotive wheel. Stator and rotor temperature-rises during starting have been determined for average acceleration torque in segmental zone (calculated from variable acceleration) which have been presented in the paper with both copper and aluminium alloy rotor bars.

Paul, R. N.; Arya, L. D.; Verma, H. K.

2012-09-01

79

Voltage Controlled Voltage Source (VCVS)  

Science.gov (United States)

Hosted by Clarkson University, this applet demonstrates a circuit that contains a voltage controlled voltage source (VCVS). The gain may be modified using the scroll bar. Even though brief, this resource can be used in a variety of different technical education classrooms.

Dorf, Richard C.; Svoboda, James A.

2008-11-27

80

Minimization of Harmonics in PWM Inverters Based on Genetic Algorithms  

Directory of Open Access Journals (Sweden)

Full Text Available This study describes a new approach based on genetic algorithm to suppress the current harmonic contents in output of an inverter. A genetic algorithm is applied to optimize a pulse width modulation (PWM inverter, which can not only spread harmonic energy but also reduce harmonic distortion. A feasible test is implemented by building a proto type three phase voltage source inverter which is designed and controlled on the basis of proposed considerations. It is verified from a practical point of view that these new approach are more effective and acceptable to minimize the harmonic distortion. Due to the complex algorithm, their realization often calls for a compromise between cost and performance.

B. Justus Rabi

2006-01-01

 
 
 
 
81

Synchronized Scheme of Continuous Space-Vector PWM with the Real-Time Control Algorithms  

DEFF Research Database (Denmark)

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 their position inside clock-intervals. In order to provide smooth shock-less pulse-ratio changing and quarter-wave symmetry of the voltage waveforms, special synchronising signals are formed on the boundaries of the 60 clock-intervals. The process of gradual transition from continuous to discontinuous synchronous PWM at higher values of the fundamental frequency has also been described. Results of analysis of the spectral characteristics of the output voltage of the inverter show advantage of synchronous PWM in comparison with conventional asynchronous modulation at low indices of the frequency ratio between the switching and the fundamental frequency. Special attention has been given to the analysis and comparison of the computational effectiveness of the proposed algorithms of synchronized modulation. 0

Oleschuk, V.; Blaabjerg, Frede

2004-01-01

82

Three-phase Resonant DC-link Converter  

DEFF Research Database (Denmark)

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 Inverter, PWM-VSI, the switches are subject to high current and voltage stress during switching, which causes losses. The fast switching of modern switches reduces switching losses. Unfortunately this procedure increased dv/dt and the size of the input/output filters of the PWM-SVI must be increased. 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 is high switching frequency combined with a high converter efficiency and low dv/dt. In the first report several resonant converters are investigated to find a resonant converter that can complete with the standard PWM-VSI converter. Four converters were selected for the theoretical analysis, and the converters are simulated. An evaluation of the resonant converters is made, and one converter is selected for the realization. In the second report the realization of the selected resonant converter is described. This includes analysis, design and test of the converter. A new control principle, using 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. A resonant converter efficiency of 97 [%] was measured. The low dv/dt of the converter makes it possible to drive long cables without filtering. A successful test with a 300 [m] long cable and an induction machine load wascarried out. It is concluded that a stable, high efficiency and high switching frequency three phase parallel resonant converter is realized.

Munk-Nielsen, Stig

1997-01-01

83

Magnetic noise caused by output waveform harmonics of voltage source inverters. Den prime atsugata inverter no shutsuryoku den prime atsu kochoha niyori shojiru jiki soon no kento  

Energy Technology Data Exchange (ETDEWEB)

Magnetic noises of loads caused by output voltage harmonics of voltage source inverters were studied by using the previously proposed equivalent noise voltage as evaluation function. Magnetic noises in various ordinary voltage source inverters such as PWM inverters with multi-pulse waveforms and PAM inverters with multi-step waveforms were quantitatively compared with each other by applying the equivalent noise voltage to them. Magnetic noises in voltage source PWM inverters were, as a result, dependent on the pulse number, and PAM inverters were lower in magnetic noise than PWM inverters. In order to reduce magnetic noises, the output waveforms of PWM inverters were improved by applying the equivalent noise voltage to the idea of harmonic elimination. In addition, by adopting a PAM system for voltage regulation in above improvement method, more improved output waveforms with less noise and distortion were obtained. 15 refs., 17 figs.

Iida, S.; Okuma, Y.; Masukawa, S. (Tokyo Denki Univ., Tokyo (Japan))

1992-04-15

84

Inverted sine carrier for fundamental fortification in PWM inverters and FPGA based implementations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper deals with a novel natural sampled pulse width modulation (PWM) switching strategy for voltage source inverter through carrier modification. The proposed inverted sine carrier PWM (ISCPWM) method, which uses the conventional sinusoidal reference signal and an inverted sine carrier, has a better spectral quality and a higher fundamental component compared to the conventional sinusoidal PWM (SPWM) without any pulse dropping. The ISCPWM strategy enhances the fundamental output voltage...

2007-01-01

85

Modeling & Simulation of Fuel cell (Choi Model) based 3-Phase Voltage Source Inverter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the present work, performance of three phase voltage source inverter, while feeding different power factor loads, has been investigated. Fuel cells models namely Choi model are used in input side as a DC source while dynamic load have been used at the output side. Dynamic load used is induction motor (IM). Performance of IM has been investigated under various loading conditions. ANN based control strategy has been proposed to find the conduction angle of a Three Phase VSI and verified for ...

Gaurav Sachdeva

2011-01-01

86

Analysis of Model Predictive Current Control for Voltage Source Inverter  

Directory of Open Access Journals (Sweden)

Full Text Available Model predictive control has become a promising control technology in power converter, because of the good dynamic response and accurate current tracking capability. This study mainly analyzes and verifies the Model Predictive Current control (MPC of a three-phase voltage sources converter. The MPC controller predicts the behavior of the converter for each possible voltage vector on each sampling interval. And a cost function is used to evaluate the voltage vector for the next sampling interval based the predicted load behavior. According to the assessment, an optimal voltage vector is selected and the corresponding switching state is applied to the converter during the next sampling interval. Finally, simulation and experimental results are demonstrated to validate the steady-state and dynamic performance of the proposed system.

Jingang Han

2013-09-01

87

A line-interactive UPS system implementation with series-parallel active power-line conditioning for three-phase, four-wire systems  

Energy Technology Data Exchange (ETDEWEB)

This paper presents a three-phase line-interactive uninterruptible power supply (UPS) system with active series-parallel power-line conditioning capabilities. Synchronous reference frame (SRF)-based controller is used to harmonic and reactive power compensation generated from any configuration of non-linear load. Under normal line conditions the UPS system works with universal filtering capabilities, such as compensating the input currents and output voltages. Two three-phase pulse width modulation (PWM) converters, called series and parallel active filters, are used to perform the series and parallel active power-line compensation. The series active power filter works as sinusoidal current source in phase with the input voltage, drawing from utility sinusoidal and balanced input currents with low total harmonic distortion (THD). The parallel active power filter works as sinusoidal voltage source in phase with the input voltage, providing regulated and sinusoidal output voltages with low THD. Operation of a three-phase phase-locked loop (PLL) structure, used in the proposed line-interactive UPS implementation, is presented and experimentally verified under distorted utility conditions. The performance of the UPS system is evaluated in three-phase, four-wire systems. Digital simulations and experimental results are presented to confirm the theoretical studies. (author)

Oliveira da Silva, S.A. [CEFET-PR, Cornelio, Procopio (Brazil). Department of Electrical Engineering; Donoso-Garcia, P.; Cortizo, P.C.; Seixas, P.F. [Federal University of Minas Gerais, Belo Horizonte (Brazil). Department of Electronic Engineering

2004-07-01

88

Voltage Source Converters with Energy Storage Capability  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This project deals with voltage source converters with energy storage capability. The main objective is to study the possible benefits of energy storage to a power system with a VSC as the interface between them. First of all, a converter control system is proposed for a two level VSC. In the conventional converter control, the control system usually takes the voltage measured at the point where the converter is connected and calculates the reference voltage for the converter; with a modulati...

Xie, Hailian

2006-01-01

89

A Novel Prototype of Auxiliary Edge Resonant Bridge Leg-Link Snubber-Assisted Soft-Switching Sinewave PWM Inverter  

Science.gov (United States)

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 gate controlled MOS power semiconductor devices which is much more improved to the low saturation voltage. The effectiveness of this is verified from a practical point of view.

Nakamura, Mantaro; Yamazaki, Takayuki; Fujii, Yuma; Ahmed, Tarek; Nakaoka, Mutsuo

90

Single Phase Voltage Source Inverter Photovoltaic Application  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Photovoltaic applications have been developing and spreading rapidly in recent times. This paper describes the control strategy of the Voltage Source Inverter that is the important tail end of many photovoltaic applications.In order to supply the grid with a sinusoidal line current without harmonic distortion, the inverter is connected to the supply network via a L-C-L filter. The output current is controlled by the hysteresis controller. To improve the behaviors of the L-C-L filter, active d...

2010-01-01

91

Comparative Study of Multicarrier PWM Techniques for a Modular Multilevel Inverter  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents the simulation of three phase five-level modular multilevel cascade inverter based on double-star chopper-cell (DSCC. The multicarrier PWM techniques such as Phase disposition PWM (PDPWM, Phase opposition disposition PWM (PODPWM, Alternate phase opposition disposition PWM (APODPWM, and Phase shift PWM (PSPWM is employed and a comparative study is done based on the spectral quality of the load voltage and load current waveforms. Simulation has been carried out for various modulation indices using MATLAB/Simulink and the results are verified.

M.S.Rajan

2014-01-01

92

Improved Indirect Rotor Flux Oriented Control of PWM inverter fed Induction Motor Drives  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In today's high-power electrical drives using vector controlled induction machines, voltage source inverters (VSI) based on PWM technology and current source inverters (CSI) based on based on PWM technology are the most important alternatives for motor supply (cyclo-converters being confined to very low speed applications). In this paper an Induction motor modeled in the rotor flux reference frame, the rotor flux orientation is obtained, a high performance current fed Indirect Rotor Flux Orie...

Gerald Christopher Raj, I.; P Renuga, Dr; Arul Prasanna, M.

2010-01-01

93

Analysis of Input and Output Ripples of PWM AC Choppers  

Directory of Open Access Journals (Sweden)

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.

Pekik Argo Dahono

2008-11-01

94

Optimum space vector PWM algorithm for three-level inverter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A Three - Level Voltage Source Inverter is used increasingly to supply a variable frequency and variable voltage for variable speed applications. A suitable pulse width modulation (PWM) technique is employed to obtain the required output voltage at the line side of the inverter. This paper studies popular multi-level topology, Diode Clamped or Neutral Point Clamped for three-level. Two methods of Sine-triangle (SPWM) and two methods of Space Vector Pulse Width Modulation (SVPWM) are employed ...

2011-01-01

95

Performance analysis of samarium cobalt P.M. synchronous motor fed from PWM inverters  

International Nuclear Information System (INIS)

This paper presents an analysis and performance of samarium cobalt permanent magnet (P.M.) synchronous motors fed from two types of voltage source pulse width modulated (PWM) inverters. The analysis and test results on the steady state performance of a P.M. motor fed from PWM inverters are presented. PWM inverters are used in variable voltage variable frequency applications to avoid a double conversion process of ordinary inverters. In drives, they are used for voltage and speed regulation of motors. Use of modulation technique in inverters also allow to eliminate or minimize selected harmonics from the inverter output voltage

1985-01-01

96

Generalized SVPWM Algorithm for Two Legged Three Phase Multilevel Inverter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper establishes the inherent fractal structure in the space vector representation of two legged three phase multilevel inverters. The established fractal structure is utilized to propose a generalized algorithm for space vector PWM generation for two legged multilevel inverters. The voltage space vectors of higher level inverters can be generated from the voltage space vectors of equivalent 2-level inverter. The proposed algorithm can be easily extended to n-level inverters without ...

Devisree Sasi; Jisha Kuruvilla P; Anish Gopinath

2013-01-01

97

Dynamic Performance of a Back-to-Back HVDC Station Based on Voltage Source Converters  

Science.gov (United States)

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.

Khatir, Mohamed; Zidi, Sid-Ahmed; Hadjeri, Samir; Fellah, Mohammed-Karim

2010-01-01

98

Comparison of a three phase single stage PV system in PSCAD and PowerFactory  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The main objective of the project is to develop a Photovoltaic (PV) system using three phase Pulse Width Modulation (PWM) converter as the interfacing component in Power factory. Already existing model in Power factory tool uses static generator as the interfacing converter. Moreover the control technique implemented within the PV model is very basic. Aworking model is already available in PSCAD simulation tool using PWM converter but it is a very detailed one in terms of modeling which resul...

2012-01-01

99

High performance direct instantaneous power control of PWM rectifiers  

International Nuclear Information System (INIS)

This paper presents a new direct instantaneous power control (DPC) strategy for active rectifiers. In this novel scheme the PWM modulator has been utilized instead of the hysteresis comparators and switching table. The required converter voltage in each sampling period is directly calculated based on the reference and measured values of powers, system parameters, and the measured voltage of the AC source through simple equations which are wisely compensated for variations of the grid voltage during a sampling period. Then, the PWM generator generates the switching pulses for the voltage source converter. It is shown that the proposed DPC-PWM exhibits several features, such as a simple algorithm, constant switching frequency, robust to sampling frequency changes, robust to inductance values mismatch, and particularly it provides low sampling frequency. Extensive simulation and experimental results have proven the excellent performance and verify the validity and effectiveness of the proposed instantaneous power control scheme.

2010-05-01

100

High performance direct instantaneous power control of PWM rectifiers  

Energy Technology Data Exchange (ETDEWEB)

This paper presents a new direct instantaneous power control (DPC) strategy for active rectifiers. In this novel scheme the PWM modulator has been utilized instead of the hysteresis comparators and switching table. The required converter voltage in each sampling period is directly calculated based on the reference and measured values of powers, system parameters, and the measured voltage of the AC source through simple equations which are wisely compensated for variations of the grid voltage during a sampling period. Then, the PWM generator generates the switching pulses for the voltage source converter. It is shown that the proposed DPC-PWM exhibits several features, such as a simple algorithm, constant switching frequency, robust to sampling frequency changes, robust to inductance values mismatch, and particularly it provides low sampling frequency. Extensive simulation and experimental results have proven the excellent performance and verify the validity and effectiveness of the proposed instantaneous power control scheme.

Monfared, Mohammad, E-mail: m.monfared@aut.ac.i [Dept. of Electrical Eng., Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Rastegar, Hassan, E-mail: rastegar@aut.ac.i [Dept. of Electrical Eng., Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Kojabadi, Hossein Madadi, E-mail: hmadadi64@yahoo.c [Dept. of Electrical Eng., Sahand University of Technology, Tabriz (Iran, Islamic Republic of)

2010-05-15

 
 
 
 
101

Behavior of three-phase induction motors with variable stator coil winding pitch  

Science.gov (United States)

A pulse-width modulation (PWM) inverter and sinusoidal output voltage supplies feeding four different chorded three-phase induction motors were tested for low-order odd voltage harmonic components and efficiency at different loads. The total harmonic distortion due to the third, fifth, and ninth harmonics was lowest in a motor with 160° coil pitch energized by both sinusoidal and PWM voltages. The efficiencies of the motor with the short-chorded winding were as much as 5% and 16% higher than that of the full-pitched motor under sinusoidal and PWM excitation, respectively, due to harmonic cancellation.

Deshmukh, R.; Moses, A. J.; Anayi, F.

2006-04-01

102

Optimal condition of memristance enhancement circuit using external voltage source  

Directory of Open Access Journals (Sweden)

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.

Hiroya Tanaka

2014-05-01

103

Optimal condition of memristance enhancement circuit using external voltage source  

Science.gov (United States)

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.

Tanaka, Hiroya; Tadokoro, Yukihiro; Iizuka, Hideo

2014-05-01

104

Performance Evaluation of Multicarrier SPWM Strategies for Three Phase Z - source Seven Level Diode Clamped Inverter  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents multicarrier PWM strategies for three phase diode clamped seven level Z-source inverter. Multilevel inverters posses the advantage of reduced harmonics,high power capability and high voltage level. Impedance network in the diode clamped multilevel inverter circuit will perform boost operation. This paper focuses on multicarriersinusoidal pulse width modulation (MCSPWM strategy for the three phase seven level Z-source diode clamped inverter. Performance parameters of three phase seven level Z-source diode clamped inverter have been analyzed. A simulation model of three phase seven level Z-source diode clamped inverter developed using MATLAB/SIMULINK and its performance has been analyzed.

V.Arun#1 , B.Shanthi

2013-06-01

105

Full-bridge type electric converter study using the ZVS-PWM-GEPAE commutation auxiliary cell; Estudo do conversor DC/DC do tipo full-bridge empregando a celula auxiliar de comutacao ZVS-PWM-GEPAE  

Energy Technology Data Exchange (ETDEWEB)

This work presents the analysis and design procedures of a new D C-D C Full Bridge PWM converter, using the ZVS-PWM-GEPAE commutation cell to achieve soft switching. Experimental results obtained from a laboratory prototype rated 1500 W area also presented. It is demonstrated that the inclusion of the auxiliary switches do not modify the PWM switching pattern. Bench tests on the prototype confirm that the proposed circuit exhibits high efficiency and behaves as a constant voltage source over an extended power output range. (author)

Castaldo, Fernando Cardoso

1994-07-01

106

A high-precision voltage source for EIT  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Electrical impedance tomography (EIT) utilizes electrodes placed on the surface of a body to determine the complex conductivity distribution within the body. EIT can be performed by applying currents through the electrodes and measuring the electrode voltages or by applying electrode voltages and measuring the currents. Techniques have also been developed for applying the desired currents using voltage sources. This paper describes a voltage source for use in applied-voltage EIT that includes...

Saulnier, Gary J.; Liu, Ning; Ross, Alexander S.

2006-01-01

107

Single-phase to three-phase converter using a resonant DC link  

Energy Technology Data Exchange (ETDEWEB)

The paper presents an improved single-phase to three-phase converter in which the switching loss is reduced by adding a resonant DC link. The operation of the proposed scheme is first established by simulating the converter using the simulation package PSPICE. An experimental single-phase to three-phase converter is built using IGBT switches controlled by digitally generated PWM signals. The waveforms of the converter feeding an induction motor load and the frequency spectra are presented.

Yuvarajan, S.; Chen, M.S.; Weng, D.F. [North Dakota State Univ., Fargo, ND (United States). Electrical Engineering Dept.

1995-12-31

108

Indirect Vector Control of Three Phase Induction Motor using PSIM  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents the implementation of indirect vector control of three phase Induction Motor using Hysteresis Band PWM current control and Synchronous Current Control in PSIM environment. In any machine drive system, current control directly influences both flux and torque developed directly. In Hysteresis current control method, actual current tracks the command current within a hysteresis band. There is no difficulty in current control tracking when CEMF is low, but at higher speeds, current controller gets saturated due to higher CEMF and hense becomes difficult to track due to which there will be a phase lag with respect to command current. All such problems are solved using Synchronous Current Control. 

Nagulapati Kiran

2014-03-01

109

Autonomous Three-Phase Induction Generator Supplying Unbalanced Loads  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a control method for a stand-alone micro hydro with induction generator (IG supplying unbalanced three-phase loads. Besides voltage and frequency regulation, the phase balancing is ensured for this particular operating regime. The proposed control topology relies on a combination between a voltage source inverter (VSI and a dump load (DL. The VSI imposes the system frequency and performs the unbalances compensation, while the DL deals with the voltage regulation. Experiments have yielded the reliability of this configuration during generator loading and unbalanced loads supply.

ION, C. P.

2013-05-01

110

A line-interactive UPS system implementation with series-parallel active power-line conditioning for three-phase, four-wire systems  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a three-phase line-interactive uninterruptible power supply (UPS system with active series-parallel power-line conditioning capabilities. Synchronous reference frame (SRF-based controller is used for harmonic and reactive power compensation generated from any configuration of non-linear loads. Under normal line conditions the UPS system works with universal filtering capabilities, such as compensating the input currents and output voltages. Two three-phase pulsewidth modulation (PWM converters, called series and parallel active filters, are used to perform the series and parallel active power-line compensation. The series active filter works as sinusoidal current source in phase with the input voltage, drawing from utility sinusoidal and balanced input currents with low total harmonic distortion (THD. The parallel active filter works as sinusoidal voltage source in phase with the input voltage, providing regulated and sinusoidal output voltages with low THD. The performance of the UPS system is evaluated in three-phase, four-wire systems. Experimental results are presented to confirm the theoretical studies.Este artigo apresenta um sistema de energia ininterrupta (SEI line-interactive trifásico com capacidade de condicionamento ativo de potência série e paralelo. Um controlador baseado no sistema de eixo de referência síncrona (SRF é usado na compensação de potência reativa e harmônica geradas por quaisquer configurações de cargas não lineares. Sob condições normais da rede elétrica o SEI trabalha na compensação das correntes de entrada e das tensões de saída. Dois conversores controlados em tensão e modulados por largura de pulso (PWM, chamados de filtros ativos série e paralelo, são usados para realizar o condicionamento ativo de potência série e paralelo. O filtro ativo série trabalha como uma fonte de corrente senoidal em fase com a tensão de entrada, drenando da rede correntes senoidais, balanceadas com baixas taxas de distorção harmônica (TDH. O filtro ativo paralelo trabalha como uma fonte de tensão senoidal em fase com a tensão de entrada, fornecendo para a carga tensões reguladas, senoidais e com baixas taxas de distorção harmônica. O desempenho do SEI é avaliado para sistemas trifásicos com quatro fios. Resultados experimentais são apresentados para confirmar os estudos teóricos.

Sérgio Augusto Oliveira da Silva

2005-06-01

111

A line-interactive UPS system implementation with series-parallel active power-line conditioning for three-phase, four-wire systems  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Este artigo apresenta um sistema de energia ininterrupta (SEI) line-interactive trifásico com capacidade de condicionamento ativo de potência série e paralelo. Um controlador baseado no sistema de eixo de referência síncrona (SRF) é usado na compensação de potência reativa e harmônica geradas por qu [...] aisquer configurações de cargas não lineares. Sob condições normais da rede elétrica o SEI trabalha na compensação das correntes de entrada e das tensões de saída. Dois conversores controlados em tensão e modulados por largura de pulso (PWM), chamados de filtros ativos série e paralelo, são usados para realizar o condicionamento ativo de potência série e paralelo. O filtro ativo série trabalha como uma fonte de corrente senoidal em fase com a tensão de entrada, drenando da rede correntes senoidais, balanceadas com baixas taxas de distorção harmônica (TDH). O filtro ativo paralelo trabalha como uma fonte de tensão senoidal em fase com a tensão de entrada, fornecendo para a carga tensões reguladas, senoidais e com baixas taxas de distorção harmônica. O desempenho do SEI é avaliado para sistemas trifásicos com quatro fios. Resultados experimentais são apresentados para confirmar os estudos teóricos. Abstract in english This paper presents a three-phase line-interactive uninterruptible power supply (UPS) system with active series-parallel power-line conditioning capabilities. Synchronous reference frame (SRF)-based controller is used for harmonic and reactive power compensation generated from any configuration of n [...] on-linear loads. Under normal line conditions the UPS system works with universal filtering capabilities, such as compensating the input currents and output voltages. Two three-phase pulsewidth modulation (PWM) converters, called series and parallel active filters, are used to perform the series and parallel active power-line compensation. The series active filter works as sinusoidal current source in phase with the input voltage, drawing from utility sinusoidal and balanced input currents with low total harmonic distortion (THD). The parallel active filter works as sinusoidal voltage source in phase with the input voltage, providing regulated and sinusoidal output voltages with low THD. The performance of the UPS system is evaluated in three-phase, four-wire systems. Experimental results are presented to confirm the theoretical studies.

Sérgio Augusto Oliveira da, Silva; Pedro F., Donoso-Garcia; Porfírio C., Cortizo; Paulo F., Seixas.

112

A high-precision voltage source for EIT.  

Science.gov (United States)

Electrical impedance tomography (EIT) utilizes electrodes placed on the surface of a body to determine the complex conductivity distribution within the body. EIT can be performed by applying currents through the electrodes and measuring the electrode voltages or by applying electrode voltages and measuring the currents. Techniques have also been developed for applying the desired currents using voltage sources. This paper describes a voltage source for use in applied-voltage EIT that includes the capability of measuring both the applied voltage and applied current. A calibration circuit and calibration algorithm are described which enables all voltage sources in an EIT system to be calibrated to a common standard. The calibration minimizes the impact of stray shunt impedance, passive component variability and active component non-ideality. Simulation data obtained using PSpice are used to demonstrate the effectiveness of the circuits and calibration algorithm. PMID:16636413

Saulnier, Gary J; Ross, Alexander S; Liu, Ning

2006-05-01

113

Design of New Single-phase Multilevel Voltage Source Inverter  

Directory of Open Access Journals (Sweden)

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.

Rasoul Shalchi Alishah

2014-07-01

114

Applying voltage sources to a Luttinger liquid with arbitrary transmission  

CERN Document Server

The Landauer approach to transport in mesoscopic conductors has been generalized to allow for strong electronic correlations in a single-channel quantum wire. We describe in detail how to account for external voltage sources in adiabatic contact with a quantum wire containing a backscatterer of arbitrary strength. Assuming that the quantum wire is in the Luttinger liquid state, voltage sources lead to radiative boundary conditions applied to the displacement field employed in the bosonization scheme. We present the exact solution of the transport problem for arbitrary backscattering strength at the special Coulomb interaction parameter g=1/2.

Egger, R; Egger, Reinhold; Grabert, Hermann

1998-01-01

115

A COMPREHENSIVE ANALYSIS OF SPACE VECTOR PWM TECHNIQUE BASED ON PLACEMENT OF ZERO-SPACE VECTOR  

Directory of Open Access Journals (Sweden)

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.

G.SAMBASIVA RAO,

2011-04-01

116

Neural network current controller for transistor PWM inverters; Neuronowy regulator pradu do tranzystorowych falownikow PWM  

Energy Technology Data Exchange (ETDEWEB)

A conception and results of simulation tests of a neural network current controller for three-phase transistor PWM inverters are presented. This converter realizes discrete modulation and can be used for both hard and soft (resonant) commutated inverters. For teaching a multilayer neural network use is made of a PWM voltage pattern generated by an optimal controller which minimizes the RMS value of current error in each sampling cycle. As shown in this article the neural network controller can guarantee a practically optimal control quality with no need for any complex optimization procedures. Therefore this controller can be used for operation with inverters of very high switching frequency. (author). 12 refs., 6 figs., 1 tab.

Kazmierkowski, M.P.; Dzieniakowski, M.A.; Sobczuk, D.L. [Politechnika Warszawska, Warsaw (Poland)

1995-07-01

117

Transistorized PWM inverter-induction motor drive system  

Science.gov (United States)

This paper describes the development of a transistorized PWM inverter-induction motor traction drive system. A vehicle performance analysis was performed to establish the vehicle tractive effort-speed requirements. These requirements were then converted into a set of inverter and motor specifications. The inverter was a transistorized three-phase bridge using General Electric power Darlington transistors. The description of the design and development of this inverter is the principal object of this paper. The high-speed induction motor is a design which is optimized for use with an inverter power source. The primary feedback control is a torque angle control with voltage and torque outer loop controls. A current-controlled PWM technique is used to control the motor voltage. The drive has a constant torque output with PWM operation to base motor speed and a constant horsepower output with square wave operation to maximum speed. The drive system was dynamometer tested and the results are presented.

Peak, S. C.; Plunkett, A. B.

1982-10-01

118

Nongrounded Common-Mode Equivalent Circuit for Brushless DC Motor Driven by PWM Inverter  

Science.gov (United States)

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.

Maetani, Tatsuo; Isomura, Yoshinori; Watanabe, Akihiko; Iimori, Kenichi; Morimoto, Shigeo

119

A battery-based, low-noise voltage source  

Science.gov (United States)

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.

Wagner, Anke; Sturm, Sven; Schabinger, Birgit; Blaum, Klaus; Quint, Wolfgang

2010-06-01

120

A battery-based, low-noise voltage source.  

Science.gov (United States)

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 x 10(-7) over 6.5 h and a noise level equal or smaller than 30 nV/square root(Hz) is achieved. PMID:20590260

Wagner, Anke; Sturm, Sven; Schabinger, Birgit; Blaum, Klaus; Quint, Wolfgang

2010-06-01

 
 
 
 
121

A Comparative Study of Sinusoidal PWM and Space Vector PWM of a Vector Controlled BLDC Motor  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper focuses on the vector control of a BLDC motor with two different concepts of Pulse Width Modulation- the Sinusoidal PWM and the Space Vector Modulation strategy. The paper deals with the basics of a BLDC motor, its dynamic modeling and its speed control using two different strategies of Pulse Width Modulation. The vector control is one of the methods used in variable frequency drives or variable speed drives to control the torque (and thus the speed) of three-phase AC electric moto...

2013-01-01

122

A Comparative Study of Sinusoidal PWM and Space Vector PWM of a Vector Controlled BLDC Motor  

Directory of Open Access Journals (Sweden)

Full Text Available This paper focuses on the vector control of a BLDC motor with two different concepts of Pulse Width Modulation- the Sinusoidal PWM and the Space Vector Modulation strategy. The paper deals with the basics of a BLDC motor, its dynamic modeling and its speed control using two different strategies of Pulse Width Modulation. The vector control is one of the methods used in variable frequency drives or variable speed drives to control the torque (and thus the speed of three-phase AC electric motors by controlling the current. The results prove that the Space Vector Modulation technique helps to improve the performance and thus the efficiency of the system.

LYDIA ANU JOSE, K.B.KARTHIKEYAN

2013-06-01

123

Comparative analysis of third harmonic injection PWM and SPWM control techniques for UPS inverter  

Energy Technology Data Exchange (ETDEWEB)

Pulse width modulation (PWM) techniques for uninterruptible power supply (UPS) applications were investigated. The results of analytical and simulation studies were studied in order to determine the equivalence between sinusoidal PWM and third harmonic PWM control technologies in relation to the high conversion factor (CF) and total harmonic distortion (THD) of UPS applications. The inverter simulation used a 3-phase 3-wire topology with a 3-level voltage source inverter. PI controller compensators were included in each of the voltage and current controllers. A voltage major loop controller was used to ensure sinusoidal output voltage. The capacitor voltage, inductor current, and load current were used as feedback control signals. Fourier transform equations were used to characterize harmonic components for double variable controlled waveforms. Results of the study demonstrated that THD-PWMs reduced the peak size of the envelope of each phase leg voltage and increased the modulation index without causing modulation. 9 refs., 1 tab., 12 figs.

Wanjekeche, T.; Nicolae, D.V.; Jimoh, A.A. [Tshwane Univ. of Technology, Pretoria (South Africa). Dept. of Electrical Engineering

2008-07-01

124

Investigation of FPGA Based PWM Control Technique for AC Motors  

Directory of Open Access Journals (Sweden)

Full Text Available This paper proposes a Random Frequency PWM synchronized for a three phase inverter implemented with use of FPGA and applied to a 1-hp induction motor drive system for the reduction of harmonics and improvement of fundamental peak voltage. For providing alternating output voltage with a specific magnitude and frequency to industrial applications, three-phase inverter is preferred.  The gating signals to the inverter are produced by means of Random Frequency PWM to significantly reduce harmonics in comparison to currently used PWMs.  FPGA is used to produce gating signals to the switches in a three-phase bridge inverter since a faster speed of operation is needed. The simulation is carried on VHSIC Hardware Description Language (VHDL using ModelSim. Then, this VHDL model is imported into Matlab environment and co-simulated using HDL Cosimulation toolbox. The simulation and experimental results are presented with a view to determine whether Random Frequency PWM performs better in terms of fundamental voltage and Total Harmonic Distortion.

Valantina Stephen

2013-02-01

125

Mathematical analysis of PWM processes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Pulse width modulation (PWM) inverters convert a direct current (DC) power supply to an alternating current (AC) supply by means of high frequency switching between two DC sources. Undesirable high-frequency components are generated in the frequency spectra of the voltages and currents of PWM inverters. The high-frequency components are ultimately removed from the input and output waveforms by filters. PWM inverters are used in a wide variety of electrical devices, ranging from microwave oven...

Ainslie-malik, Gregory R.

2013-01-01

126

Voltage harmonic variation in three-phase induction motors with different coil pitches  

Science.gov (United States)

A pulse-width modulation (PWM) inverter feeding four different chorded three-phase induction motors was tested for low-order odd harmonic voltage component and efficiency at different loads. Total harmonic distortion (THD) due to 3rd, 5th and 9th harmonics was less in a motor with 160° coil pitch. Particular harmonic order for each coil pitch was suppressed and the efficiency of a 120° coil pitch motor was increased by 7.5%.

Deshmukh, Ram; Moses, Anthony John; Anayi, Fatih

2006-09-01

127

Voltage harmonic variation in three-phase induction motors with different coil pitches  

International Nuclear Information System (INIS)

A pulse-width modulation (PWM) inverter feeding four different chorded three-phase induction motors was tested for low-order odd harmonic voltage component and efficiency at different loads. Total harmonic distortion (THD) due to 3rd, 5th and 9th harmonics was less in a motor with 160o coil pitch. Particular harmonic order for each coil pitch was suppressed and the efficiency of a 120o coil pitch motor was increased by 7.5%

2006-09-01

128

Control of Grid Integrated Voltage Source Converters under Unbalanced Conditions : Development of an On-line Frequency-adaptive Virtual Flux-based Approach  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Suul, Jon Are

2012-01-01

129

Stable d-c high-voltage source  

International Nuclear Information System (INIS)

The electric circuit is proposed and described of a stable high-voltage d-c source for supplying radiation detectors. The output of a stable a-c low-voltage source is connected to the input of an amplifier whose output is connected by capacitance of a capacitor to the transformer primary. A rectifier or a voltage multiplier with filter is connected to the transformer secondary, with a feedback inserted between the transformer secondary and the amplifier input circuit. (J.K.)

1975-01-01

130

Parallel operation of voltage-source converters: issues and applications  

Energy Technology Data Exchange (ETDEWEB)

Technological advancements in power electronics have prompted the development of advanced AC/DC conversion systems with high efficiency and flexible performance. Among these devices, the Voltage-Source Converter (VSC) has become an essential building block. This paper considers the parallel operation of VSCs under different system conditions and how they can assist the operation of highly complex power networks. A multi-terminal VSC-based High Voltage Direct Current (M-VSC-HVDC) system is chosen to be modeled, simulated and then analyzed as an example of VSCs operating in parallel. (author)

Almeida, F.C.B.; Silva, D.S. [Federal University of Juiz de Fora (UFJF), MG (Brazil)], Emails: felipe.brum@engenharia.ufjf.br, salomaoime@yahoo.com.br; Ribeiro, P.F. [Calvin College, Grand Rapids, MI (United States); Federal University of Juiz de Fora (UFJF), MG (Brazil)], E-mail: pfribeiro@ieee.org

2009-07-01

131

Generalized SVPWM Algorithm for Two Legged Three Phase Multilevel Inverter  

Directory of Open Access Journals (Sweden)

Full Text Available This paper establishes the inherent fractal structure in the space vector representation of two legged three phase multilevel inverters. The established fractal structure is utilized to propose a generalized algorithm for space vector PWM generation for two legged multilevel inverters. The voltage space vectors of higher level inverters can be generated from the voltage space vectors of equivalent 2-level inverter. The proposed algorithm can be easily extended to n-level inverters without any computational complexity and it doesn’t use any look up table for sector identification. The paper explains the proposed method for 5-level inverter and simulation results are presented for 2-level, 3-level and 5-level configurations in MATLAB/SIMULINK.

Devisree Sasi

2013-07-01

132

Using voltage sources as current drivers for electrical impedance tomography  

Science.gov (United States)

In multi-frequency electrical impedance tomography (EIT) systems it is much easier to design voltage sources than current sources. It is also at times desirable to operate a voltage driving system as if it were a current driving system. This can be done by adjusting the individual voltage sources until a desired current pattern is obtained. Questions remain regarding the form of the adjustment algorithm and the circumstances under which it will converge. Through simulation and experimentation we have developed a simple algorithm which functions satisfactorily in most practical situations. We have also investigated its theoretical limits for convergence. Simulations showed that convergence is reached in all cases with little (0.1%) or no measurement noise. With moderate noise (0.5%) our algorithm failed to converge in 17 out of 6000 runs, while more significant measurement noise (1%) resulted in convergence in only 7 out of 6000 runs. Experiments with a 16-channel EIT system converged in all cases on volunteer arms, but failed some of the time in saline, with the number of successful runs decreasing with frequency (73.3% at 10 kHz, 71.1% at 125 kHz and 15.5% at 750 kHz), suggesting a possible link to measurement error.

Hartov, Alex; Demidenko, Eugene; Soni, Nirmal; Markova, Mariana; Paulsen, Keith

2002-09-01

133

Phase-Locked Loop for Grid-Connected Three-Phase Power Generation Systems  

Energy Technology Data Exchange (ETDEWEB)

Analysis and design of a phase-locked loop (PLL) are presented for the power factor control of grid-connected three-phase power generation systems. The dynamic characteristics of the closed loop PLL system with a second order is investigated and the optimization method is discussed. In particular, the performance of the PLL in the three-phase system is analyzed in the distorted utility conditions such as the phase unbalancing, harmonics, and offset caused by the nonlinearities and measurement errors. The PLL technique for the three-phase system is implemented in software of a digital signal processor (DSP) to verify the analytic results and the experiments are carried out for various utility conditions. Finally, this technique is applied to the grid-connected photovoltaic power generation system with the current-controlled PWM inverter. The experimental results well show its phase tracking capability in the three-phase grid-connected operation. (author). 10 refs., 12 figs., 1 tab.

Chung, S.K. [Gyeongsang National University, Chinju (Korea)

1999-12-01

134

Three-phase electric drive with modified electronic smoothing inductor  

DEFF Research Database (Denmark)

This paper presents a three-phase electric drive with a modified electronic smoothing inductor (MESI) having reduced size of passive components. The classical electronic smoothing inductor (ESI) is able to control a diode bridge output current and also reduce not only mains current harmonics but also output voltage ripple. ESI performs the function of an inductor that has controlled variable impedance. MESI requires active switches with lower ratings than ESI and has the same performance. In MESI, an active voltage source realized by a low-voltage switch-mode converter stage is inserted in series with DC-link capacitor. This increases power factor (PF) and reduces the total harmonic distortions (THDs) in current at mains. Input currents of the diode bridge which usually show high peak amplitudes are converted into a 120° rectangular shape which ideally results in a total PF of 0.955 and THDs of 31%, by electronic smoothing techniques.

Singh, Yash Veer; Rasmussen, Peter Omand

2010-01-01

135

Analysis and Minimization of Output Current Ripple of Multiphase Carrier-Based PWM Inverters  

Directory of Open Access Journals (Sweden)

Full Text Available Analysis and minimization of output current ripple of multiphase carrier-based PWM inverters are presented in this paper. Analytical expression of rms value of output current ripple of multiphase PWM inverters as a function of the reference signal is first derived. Based on this expression, it is shown that a pure sinusoidal signal is the optimum reference signal that results in minimum output current ripple. Different to three-phase PWM inverters, injection of harmonics into the sinusoidal reference signal is neither necessary nor useful. The rms values of output current ripple of 5-, 7-, and 9-phase PWM inverters under various reference signals are compared. Experimental results are included to show the validity of the analysis method.

Pekik Argo Dahono

2010-05-01

136

The Application of FPGA in PWM Controlled Resonant Converter for an Ozone Generator  

Directory of Open Access Journals (Sweden)

Full Text Available Pulse Width Modulation (PWM is a very common technique used in many different applications. The Conventional method its generation is the heart of the inverter system. This paper present methodology to generate Sinusoidal PWM (SPWM signal for three-phase inverter based on EP20K200EFC484-2x Altera Field Programmable Gate Array (FPGA. Designing a PWM inverter drive using FPGA has several advantages, such as: it's quick, very modifiable, and very suitable for prototyping. In this paper, the PWM signal is used control switching action conducted by MOSFET as part of power electronics devices in resonant power converter which has 24 volt DC input voltage. As the result, by using resonant oscillation controlled by FPGA the high sinusoidal voltage until 1.0 kV peak-to peak has been generated in the load side.

Mochammad Facta

2013-07-01

137

Measurements of power loss distribution in a typical stator core under PWM voltage excitation  

Science.gov (United States)

The pulse width modulated (PWM) inverter is widely used to feed small induction motors for variable speed and torque control. When a laminated stator core is energised in this way additional iron losses occur due to localised distorted flux. Flux density and power loss distribution under PWM and sinusoidal voltage excitations were measured in a typical induction motor stator core lamination at 1.3 T, 50 Hz by using a computer-aided magnetising system to set up flux distribution as would occur in a practical three-phase stator core. The iron loss increased 15-20% under PWM excitation. The loss increase under PWM excitation in the stator core laminations was 3% lower than in Epstein strips of the same electrical steel under the same conditions showing an effect of the magnetic circuit geometry.

Tutkun, N.; Moses, A. J.

2003-06-01

138

Measurements of power loss distribution in a typical stator core under PWM voltage excitation  

International Nuclear Information System (INIS)

The pulse width modulated (PWM) inverter is widely used to feed small induction motors for variable speed and torque control. When a laminated stator core is energised in this way additional iron losses occur due to localised distorted flux. Flux density and power loss distribution under PWM and sinusoidal voltage excitations were measured in a typical induction motor stator core lamination at 1.3 T, 50 Hz by using a computer-aided magnetising system to set up flux distribution as would occur in a practical three-phase stator core. The iron loss increased 15-20% under PWM excitation. The loss increase under PWM excitation in the stator core laminations was 3% lower than in Epstein strips of the same electrical steel under the same conditions showing an effect of the magnetic circuit geometry

2003-06-01

139

FIELD PROGRAMMABLE GATE ARRAY BASED RF-THI PULSE WIDTH MODULATION CONTROL FOR THREE PHASE NVERTER USING MATLAB MODELSIM COSIMULATION  

Directory of Open Access Journals (Sweden)

Full Text Available This study proposes different configurations of PWM techniques for harmonic reduction and improvement of fundamental peak voltage. For providing adjustable frequency power to industrial applications, three-phase inverter is preferred. The general aim of this study is to reduce the third order harmonics and improve the Harmonic Spread Factor by different PWM techniques using matlab modelsim cosimulation. The gating signals to the inverter are produced by means of SPWM, RFPWM, Third Harmonic Injection (THI and Hybrid Random Frequency THIPWM. FPGA because of its suitability in time critical systems it is used to produce gating signals to the switches in a three-phase bridge inverter. This study will provide the insight of trends and technologies of Third Order Harmonic Elimination and improvement of HSF using different PWM techniques. In addition, a performance comparison of proposed methods with modified PWM methods is also provided. The result of the proposed work shows that there is improvement in fundamental voltage, THD, HSF when a combination of RF-THI PWM techniques is used.

Valantina Stephen

2012-01-01

140

Asymmetric Carrier Random PWM  

DEFF Research Database (Denmark)

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 as in closed loop motor control applications.

Mathe, Laszlo; Lungeanu, Florin

2010-01-01

 
 
 
 
141

Review of multilevel voltage source inverter topologies and control schemes  

International Nuclear Information System (INIS)

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.

2011-02-01

142

High-Speed Fuses in IGBT based Voltage Source Converters  

DEFF Research Database (Denmark)

The demand for protection of power electronic applications has during the last couple of years increased regarding the high-power IGBT modules. Even with an active protection, a high power IGBT still has a risk of exhibiting a violent rupture in the case of a fault if IGBT fuses do not protect it. By introducing fuses into voltage source converters a better protection of IGBTs can be achieved. This paper is a complete overview of a research project carried out in cooperation by Aalborg University, Denmark and Cooper Bussmann International. This paper discusses three main issues regarding the IGBT fuse protection. First, the problem of adding inductance in the DC-link circuit is treated, second a short discussion of the protection of the IGBT module is done, and finally, the impact of the high frequency loading on the current carrying capability of the fuses is presented.

Iov, Florin; Blaabjerg, Frede

2005-01-01

143

Modeling synchronous voltage source converters in transmission system planning studies  

Energy Technology Data Exchange (ETDEWEB)

A Voltage Source Converter (VSC) can be beneficial to power utilities in many ways. To evaluate the VSC performance in potential applications, the device has to be represented appropriately in planning studies. This paper addresses VSC modeling for EMTP, powerflow, and transient stability studies. First, the VSC operating principles are overviewed, and the device model for EMTP studies is presented. The ratings of VSC components are discussed, and the device operating characteristics are derived based on these ratings. A powerflow model is presented and various control modes are proposed. A detailed stability model is developed, and its step-by-step initialization procedure is described. A simplified stability model is also derived under stated assumptions. Finally, validation studies are performed to demonstrate performance of developed stability models and to compare it with EMTP simulations.

Kosterev, D.N. [Oregon State Univ., Corvallis, OR (United States)

1997-04-01

144

Multilevel cascade voltage source inverter with seperate DC sources  

Energy Technology Data Exchange (ETDEWEB)

A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

Peng, Fang Zheng (Knoxville, TN); Lai, Jih-Sheng (Blacksburg, VA)

2002-01-01

145

Multilevel cascade voltage source inverter with seperate DC sources  

Energy Technology Data Exchange (ETDEWEB)

A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

Peng, Fang Zheng (Oak Ridge, TN); Lai, Jih-Sheng (Knoxville, TN)

1997-01-01

146

Power Quality Improvement using Dual Voltage Source Converter Based DVR  

Directory of Open Access Journals (Sweden)

Full Text Available In any power system, The modelling and simulation of three and seven-level Dual Voltage Source Converter based dynamic voltage restorer (DVR aimed at correcting the supply voltage sag/swell and interruption in low voltage distribution networks. The proposed design models of DVSC based DVR are expected to be most powerful solutions to minimize supply voltage disturbances of the sensitive loads. A DVR is a VSC based power electronics device connected in series between the supply and the critical loads, which are to be protected from the supply side voltage quality problems, other than outages, by injecting the required compensating voltage through DVR into the distribution line. The proposed models of DVR together with the controllers are simulated by using MAT LAB Simulink and the results are presented to assess the performance of each device.

A.Suresh

2014-01-01

147

Design of a Three-Phase Statcom-Based Inductive Static VAR Compensator Using DC Capacitor Voltage Control Scheme  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, a three-phase continuously controlled harmonic-free inductive static VAR compensator is presented. The compensator is built of a three-phase voltage source inverter based statcom. The phase currents of this compensator are linearly and continuously controlled by the statcom DC capacitor voltage. The control strategy is outlined by a process of forcing the capacitor voltage to follow a certain reference voltage which can be varied linearly from its maximum to its minimum values to produce balanced three-phase inductive currents varying in the range of zero to maximum value (I MAX The proposed compensator was verified on the computer program PSpice.

Abdulkareem Mokif Obais

2013-02-01

148

Voltage space vector's computation for current control in three phase converters / Cómputo del vector espacial de voltaje para control de corriente en convertidores trifásicos  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: English Abstract in spanish Este trabajo presenta dos técnicas de control de corriente para convertidores trifásicos de voltaje trabajando como rectificadores controlados, operando con factor de potencia unitario. El primer algoritmo está basado en la escogencia del mejor vector natural, entre los 7 vectores espaciales natural [...] es del convertidor de dos niveles de voltaje trifásico, mediante una función de costo. El segundo está basado en el cómputo y síntesis del vector espacial óptimo de convertidores trifásicos tal que se obtiene el vector que proporciona un mínimo absoluto de la función de costo. El primer algoritmo es un método sencillo que controla muy bien el factor de potencia y presenta una considerable compensación del contenido armónico. El segundo algoritmo provee una nueva fórmula cerrada para calcular el vector de voltaje óptimo aplicado al convertidor. Para este segundo método se necesita generar la señal de control con un modulador de ancho de pulso para así controlar directamente la corriente de línea permitiendo seguir la referencia de corriente. Las simulaciones y resultados experimentales muestran las ventajas del algoritmo propuesto. Abstract in english This work presents two current loop techniques, for three phase voltage source converters (VSC) used as controlled rectifiers (CR) operating at unity power factor. The first one is based on choosing the best natural vector, among the natural space vectors produced by two level voltage source inverte [...] rs, with the use of a cost function. The second one is based on computing and synthesizing a space vector such that an absolute minimum in the cost function is obtained. The first algorithm is a simple method that presents power factor correction and good total harmonic distortion compensation. The second algorithm provides a novel and closed form formula to calculate the optimum voltage vector applied by the converter. In this method, pulse width modulation (PWM) is required to modulate the voltage vector that controls directly the line current, to follow the current reference. The simulations and experimental results show the advantages of the proposed control algorithm.

Alberto, Berzov; Julio, Viola; José, Restrepo.

149

Component-Minimized Buck-Boost Voltage Source Inverters  

DEFF Research Database (Denmark)

This paper presents the design of buck-boost B4 inverters that can be derived from either Ä?uk- or SEPIC-derived buck-boost B6 inverters. Unlike traditional inverters, the integration of front-end voltage boost circuitry and inverter circuitry allows it to perform buck-boost voltage inversion. In order to form a distinct neutral potential in the corresponding voltage boost circuitry for correct B4 inverter operation, necessary modifications are derived step by step. The resulted dc networks with symmetrical placement of passive components allow complete charging and equal energy distribution between capacitors. Modulation wise, the proposed buck-boost B4 inverters can be controlled using a carefully designed carrier-based pulse-width modulation (PWM) scheme that will always ensure balanced threephase outputs as desired, while simultaneously achieving minimal voltage stress across semiconductors. Besides the advantage of reduced active components, buck-boost B4 inverters use a little more passive components when compared with buck-boost B6 inverters, which would allow a selectable tradeoff in practice. Moreover, analysis for discontinuous conduction mode of inductor current reveals the additional voltage relationship between dc input and ac output which is beyond the expectation when continuous inductor current is assumed. These theoretical findings, together with the inverter practicality, have been confirmed in Matlab/PLECS simulations and  experimentally using laboratory implemented inverter prototypes.

Gao, F.; Loh, P.C.

2007-01-01

150

IGBT Fuses for Protection Against Explosion in Voltage Source Converters  

DEFF Research Database (Denmark)

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- and IGBT Fuses in the DC-link is investigated. The current distribution in fuses is discussed when high frequency components are present in the load current. Further it is discussed how the extra cost for IGBT fuses may be balanced by ease of maintenance and less downtime of manufacturing equipment.

Blaabjerg, Frede; Iov, Florin

2004-01-01

151

Diode-assisted buck-boost voltage source inverters  

DEFF Research Database (Denmark)

This paper proposes buck-boost voltage source inverters with a unique X-shape diode-capacitor network inserted between inverter circuitry and dc source for producing a large voltage boost gain. Comparing with other voltage buck-boost techniques, the presented topologies with only a little more passive components can significantly enhance voltage boost capability for dc-ac inversion. With different front-end circuitries, the diode-assisted buck-boost inverters can show different operational principle and voltage boost ratio. Carefully analyzing the operational principle for the inherent energy charging and discharging processes of passive components reveals that the dc-link voltage can alternate between two levels, which therefore demonstrate the phenomena that the specified modulation schemes should note. A modulation scheme that can achieve optimized harmonic switching is first designed with symmetrical state placement in each switching sequence to avoid unnecessary voltage stress across both passive and active components. To reduce the total commutation count, the designed modulation scheme is then modified without increasing voltage stress. All theoretical findings were verified experimentally using a number of scale-down laboratory prototypes.

Gao, F.; Loh, P.C.

2007-01-01

152

Performance of voltage source multilevel inverter - fed induction motor drive using Simulink  

Directory of Open Access Journals (Sweden)

Full Text Available This paper deals with performance of voltage source multilevel inverter-fed induction motor drive. A Voltage source inverter (VSI is compared with multilevel inverter. A conventional Voltage Source Inverter-fed induction motor drive is modeled and simulated using Matlab/ Simulink and the results are presented. Multilevel inverter employing Selective Harmonic Elimination (SHE method is also simulated and the corresponding results are presented. The FFT spectrum for the outputs is analyzed to study the reduction in harmonics.

Neelashetty Kashappa

2011-06-01

153

Microprocessor based area sampling technique for neutral point clamped PWM inverter  

Science.gov (United States)

Recent advances in microelectronics, power devices and other technological areas have made it possible to design and develop three-phase, variable frequency, variable voltage, switching power inverters to drive three-phase ac motor and for a variety of other applications. In these systems, the microprocessor is playing an increasingly larger role for generating complex control signals, which were previously not possible by conventional linear and digital IC's. This paper discusses a microprocessor based switching control signal for three phase neutral point clamped pulse width modulated inverter which has been designed and developed to minimize the lower harmonics in the output voltage. These complex PWM switching signals (PWM patterns) can be computed and generated in real time with good harmonic spectrum by using fast microprocessors.

Shekhawat, S. S.; Dhyanchand, J.; Thollot, P.

154

Low-cost PWM speed controller for an electric mini-baja type vehicle  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paperwork presents a Pulse Width Modulation (PWM) speed controller for an electric mini-baja-type car. A battery-fed 1-kW three-phase induction motor provides the electric vehicle traction. The open-loop speed control is implemented with an equal voltage/frequency ratio, in order to maintain a constant amount of torque on all velocities. The PWM is implemented by a low-cost 8-bit microcontroller provided with optimized ROM charts for distinct speed value implementations, synchronized tra...

2007-01-01

155

RANDOM PWM ALGORITHMS FOR VSI FED INDUCTION MOTOR DRIVES WITH FIXED SWITCHING FREQUENCY  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents two random PWM algorithms for voltage source inverter fed induction motor drives with fixed switching frequency for reduced harmonic distortion and acoustical noise. Moreover, the proposed algorithms use the concept of imaginary switching times, which reduces the complexity involved in the classical space vector approach. The first algorithm is developed by randomizing the time durations of zero voltage vector times and second algorithm is developed by using the variable delay technique. To validate theeffectiveness of the proposed algorithm, numerical simulation studies have been carried out on v/f controlled induction motor drives at different modulation indices and results are presented and compared.

K. SATYANARAYANA,

2010-12-01

156

Novos algoritmos de limitação para inversores de tensão PWM a quatro braços utilizando modulação space vector  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Este artigo propõe dois novos algoritmos de limitação para inversores de tensão trifásicos a quatro braços. Estes baseiam-se na limitação do vetor de comando dentro da região de operação linear do inversor. O primeiro algoritmo utiliza um elipsóide inscrito no dodecaedro definido pelas extremidades [...] dos possíveis vetores de comutação do inversor, e o segundo é baseado nos planos limites desse poliedro. Uma descrição detalhada, abordando os principais pontos requeridos para a implementação digital, da modulação space vector e dos algoritmos de limitação são apresentados. Ainda, as tensões de saída e as correntes nos indutores são dinamicamente reguladas, por meio de servo controladores MIMO em eixos síncronos dq0. Estes controladores são projetados usando a técnica do regulador linear quadrático discreto de regime permanente, o qual assegura estabilidade para o sistema em toda a faixa de operação. Além disso, para prover transições suaves entre os diferentes modos de operação do inversor, são propostos algoritmos MIMO não lineares para limitar a sobrecarga da ação integral, quando o vetor de comando for limitado, e atualizar dinamicamente as variáveis dos servo controladores. Finalmente, são apresentados resultados experimentais obtidos de um protótipo de 15 kVA, totalmente controlado por um DSP TMS320F241, para validar os algoritmos propostos e demostrar o desempenho do sistema como um todo. Abstract in english This paper proposes two novel limiting algorithms for three-phase four-leg voltage source inverters to constrain the command vector inside the dodecahedron defined by the boundaries of the inverter linear operating range. The first algorithm uses an inscribed ellipsoid on the dodecahedron, and the s [...] econd one is based on the polyhedron boundary planes. A detailed description, with the key points required for a digital implementation of space vector and limiting algorithms, is given. In addition, the output voltages and the inductors currents are dynamically regulated by means of MIMO servo controller in dq0 coordinates. These controllers are designed using optimal discrete linear quadratic regulator technique, which ensures stability for the system at all operating conditions. In order to provide smooth transitions among the different modes of operation, nonlinear MIMO anti-windup algorithms are proposed to dynamically update the controllers servo variables. Finally, experimental results on a 15 kVA PWM inverter fully controlled by a DSP controller, TMS320F241, has been used to validate the feasibility of the proposed algorithm and to demonstrate the performance of the overall system.

Camargo, Robinson F. de; Botterón, Fernando; Pinheiro, Humberto; Pinheiro, José R.; Gründling, Hilton; Hey, Hélio.

157

Novos algoritmos de limitação para inversores de tensão PWM a quatro braços utilizando modulação space vector  

Directory of Open Access Journals (Sweden)

Full Text Available Este artigo propõe dois novos algoritmos de limitação para inversores de tensão trifásicos a quatro braços. Estes baseiam-se na limitação do vetor de comando dentro da região de operação linear do inversor. O primeiro algoritmo utiliza um elipsóide inscrito no dodecaedro definido pelas extremidades dos possíveis vetores de comutação do inversor, e o segundo é baseado nos planos limites desse poliedro. Uma descrição detalhada, abordando os principais pontos requeridos para a implementação digital, da modulação space vector e dos algoritmos de limitação são apresentados. Ainda, as tensões de saída e as correntes nos indutores são dinamicamente reguladas, por meio de servo controladores MIMO em eixos síncronos dq0. Estes controladores são projetados usando a técnica do regulador linear quadrático discreto de regime permanente, o qual assegura estabilidade para o sistema em toda a faixa de operação. Além disso, para prover transições suaves entre os diferentes modos de operação do inversor, são propostos algoritmos MIMO não lineares para limitar a sobrecarga da ação integral, quando o vetor de comando for limitado, e atualizar dinamicamente as variáveis dos servo controladores. Finalmente, são apresentados resultados experimentais obtidos de um protótipo de 15 kVA, totalmente controlado por um DSP TMS320F241, para validar os algoritmos propostos e demostrar o desempenho do sistema como um todo.This paper proposes two novel limiting algorithms for three-phase four-leg voltage source inverters to constrain the command vector inside the dodecahedron defined by the boundaries of the inverter linear operating range. The first algorithm uses an inscribed ellipsoid on the dodecahedron, and the second one is based on the polyhedron boundary planes. A detailed description, with the key points required for a digital implementation of space vector and limiting algorithms, is given. In addition, the output voltages and the inductors currents are dynamically regulated by means of MIMO servo controller in dq0 coordinates. These controllers are designed using optimal discrete linear quadratic regulator technique, which ensures stability for the system at all operating conditions. In order to provide smooth transitions among the different modes of operation, nonlinear MIMO anti-windup algorithms are proposed to dynamically update the controllers servo variables. Finally, experimental results on a 15 kVA PWM inverter fully controlled by a DSP controller, TMS320F241, has been used to validate the feasibility of the proposed algorithm and to demonstrate the performance of the overall system.

Robinson F. de Camargo

2004-09-01

158

Standalone self-excited induction generator with a three-phase four-wire active filter and energy storage system  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper proposes a system, based on a selfexcited induction generator with a shunt electronic converter, to feed isolated three-phase and single-phase linear or nonlinear loads. The electronic converter is composed by a three-phase four-wire voltage source inverter (VSI) and, connected to its dc side, two dc/dc converters. The VSI compensates the current harmonics, the reactive power and the load unbalances. The first of the dc/dc converters is a battery charger/discharger and the other co...

2007-01-01

159

A Fuzzy-Based Approach for the Diagnosis of Fault Modes in a Voltage-Fed PWM Inverter Induction Motor Drive  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper investigates the use of fuzzy logic for fault detection and diagnosis in a pulsewidth modulation voltage source inverter (PWM-VSI) induction motor drive. The proposed fuzzy technique requires the measurement of the output inverter currents to detect intermittent loss of firing pulses in the inverter power switches. For diagnosis purposes, a localization domain made with seven patterns is built with the stator Concordia current vector. One is dedicated to the healthy domain and the ...

Zidani, Fatiha; Diallo, Demba; Benbouzid, Mohamed; Nai?t-sai?d, Rachid

2008-01-01

160

A Study for High-Order Harmonic Resonance Phenomena of Voltage Sourced Converter in Cable System  

Science.gov (United States)

This paper presents high-order harmonic resonance phenomena of voltage sourced converter (VSC). When a voltage sourced converter is connected to power system with cables, there is possibility that minute high-order harmonic voltages of a voltage sourced converter are magnified by a series resonance and a parallel resonance, and high-order harmonic resonance phenomena are found by this study. The cause of high-order harmonic resonance phenomena is investigated and figured out by the analysis using EMTP. In addition, it is verified that high-order harmonic resonance phenomena occur as a practical matter.

Nakajima, Tatsuhito; Suzuki, Hirokazu; Temma, Koji; Iyoda, Isao

 
 
 
 
161

Shunt active filter algorithms for a three phase system fed to adjustable speed drive  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents the simulation of Shunt Active Power filter by using two different control schemes, Indirect current control technique and Synchronous detection technique by using ANN. These two control techniques are working under both balanced and unbalanced three phase voltage source conditions and it is feeding to aadjustable speed drive the torque speed characteristics of a motor is presented. Indirect current control technique is implemented under dynamic load condition and load balanced condition. The equal current distribution method of synchronous detection theory is used here to calculate the three phase compensating currents to be provided by the active filter. For calculating sequence currents neural network is used. Neural network is used for estimation of distorted waves, delay less harmonic filtering.

Sujatha.CH

2011-10-01

162

Input/output harmonic free current link three-phase AC power supply  

Science.gov (United States)

The three-phase current link AC to AC power supply, a relatively new topology for AC power supply application, has several potential advantages such as smaller number of magnetic components, lower switching frequency and more rugged operation. Despite this, it has received very little attention by the researchers, and the majority of work found in the literature is confined to the application of voltage type converters in this area. This thesis presents a comprehensive systematic approach for steady state/dynamic analysis and design of three-phase current link AC to AC power supplies. Concept of PWM methods in three-phase current type converters (CTC) is explained and the associated constraints in PWM pattern generation are addressed. Several PWM techniques are described and their performance from different aspects are compared. A steady state analysis is presented based on the Fourier representation of PWM waveforms which allows an accurate prediction of the relationships between the fundamental/harmonic components of the waveforms and other system parameters. Expressions governing various steady state characteristics of the system are derived. A dynamic model using the concept of local average of signals is established. The agreement between the dynamic behavior of switching system and derived model is illustrated. Phenomenon of multiple crossing is explained and the necessary requirement for avoiding such a phenomenon is obtained. The concept of internal model controllers is introduced and its application in the inverter control system for achieving zero steady state error is described. A detailed design procedure is presented. Root-locus method is used to design the system controllers. The applicability of different models in different design problems is discussed. All s-domain designs are verified by time-domain simulations. Experiments are conducted on a 2 KVA, 60 Hz to 50 Hz power supply. A 32 bit DSP-base high performance controller is used to implement the control system. The predicted steady state and dynamic results as well as the time-domain simulations are experimentally verified.

Karshenas, Hamid Reza

163

Space Vector Pulse Width Modulation Schemes for Two-Level Voltage Source Inverter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Space Vector Pulse Width Modulation (SVPWM) method is an advanced, computation intensive PWM method and possibly the best among all the PWM techniques for variable frequency drive applications. The SVPWM is an alternative method for the determination of switching pulse width and their position. The major advantage of SVPWM stem from the fact that, there is a degree of freedom of space vector placement in a switching cycle. This feature improves the harmonic performance of this method. This me...

Tripura, P.; Kishore Babu, Y. S.; Tagore, Y. R.

2011-01-01

164

FPGA Implementation of a General Space Vector Approach on a 6-Leg Voltage Source Inverter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A general algorithm of a Space Vector approach is implemented on a 6-leg VSI controlling a PM synchronous machine with three independent phases. In this last case, the necessity of controlling the zero-sequence current motivates the choice of a special family of vectors, different of this one used in Pulse Width Modulation (PWM) intersective strategy and in common Space Vector PWM (SVPWM). To preserve the parallelism of the algorithm and fulfill the execution time constraints, the implementat...

Sandulescu, Paul; Idkhajine, Lahoucine; Colas, Fre?de?ric; Kestelyn, Xavier; Semail, Eric; Bruyere, Antoine

2011-01-01

165

Versatile Programer for the Hewlett-Packard 6130B Digital Voltage Source.  

Science.gov (United States)

A digital programer has been designed and fabricated to generate digital input data for the Hewlett-Packard 6130B Digital Voltage Source (DVS). The programer is capable of producing approximate sawtooth and triangle waveforms from the DVS by repetitively ...

V. J. Organic

1973-01-01

166

Semiconductor Light-Controlled Instrument Transducer with Direct PWM Output for Automatic Control Systems  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish Cualquier sistema de instrumentación consiste de tres elementos: el sensor o dispositivo de entrada, el procesador de señales, y el receptor o dispositivo de salida. Diversos sistemas de control automático o con retroalimentación requieren una señal eléctrica de salida en forma de pulsos con modulac [...] ión en su ancho (PWM). Generalmente la señal analógica de salida se transforma usando un convertidor de señal PWM. En este trabajo se muestra que una señal de salida PWM, con una razón ancho-de-pulso/período (duty cycle) controlado por la intensidad de la iluminación, puede obtenerse directamente utilizando un circuito que contiene un capacitor metal (compuerta semitransparente) -óxido-semiconductor (MOS-C) conectado en serie con una fuente de DC y un generador de funciones que proporciona un voltaje periódico en forma de dientes de sierra. Internamente, la conversión de señal a PWM se logra explotando los procesos físicos fuera de equilibrio que se presentan dentro del sustrato de silicio del MOS-C. La señal cuadrada PWM, cuya amplitud está limitada a 10-20 V, se obtiene mediante la amplificación de la señal de transductor usando un amplificador estándar de transimpedancia de 60 dB. La señal de salida amplificada presenta una forma de onda PWM positiva y negativa que pueden separarse usando diodos. La razón ancho-de-pulso/período de la parte positiva es proporcional a la intensidad de la iluminación, mientras que la parte negativa es inversamente proporcional a dicha intensidad. La frecuencia de operación de este instrumento se encuentra en el rango de 1 Hz hasta algunos kilohertz. La razón ancho-de-pulso/período de la señal de salida PWM varía entre 2 y 98% cuando la potencia de la iluminación es del orden de microwatts. Este nuevo transductor o sensor podría ser útil para aplicaciones en control automático, en robótica, control de iluminación, sistemas de retroalimentación, y para la detección óptica de posición sin contacto para mediciones de centrado y anulación. Finalmente, se presenta una descripción detallada de los principios físicos y de operación de este nuevo transductor. Abstract in english This work shows that the direct PWM output electric signal, with a duty cycle controlled by light intensity, can be obtained using a circuit containing a saw-tooth voltage generator connected in series with a dc voltage source and a metal (semitransparent gate) oxide semiconductor capacitor (MOS-C). [...] 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.

O., Malik; F. J., De la Hidalga-W..

167

An Algorithm for Applying Multiple Currents Using Voltage Sources in Electrical Impedance Tomography  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A method to produce a desired current pattern in a multiple-source EIT system using voltage sources is presented. Application of current patterns to a body is known to be superior to the application of voltage patterns in terms of high spatial frequency noise suppression, resulting in high accuracy in conductivity and permittivity images. Since current sources are difficult and expensive to build, the use of voltage sources to apply the current pattern is desirable. An iterative algorithm pre...

2008-01-01

168

Análise e implementação de retificadores PWM trifásicos com resposta de tempo mínimo utilizando desacoplamento por retroação de estados  

Directory of Open Access Journals (Sweden)

Full Text Available Este trabalho desenvolve um procedimento de projeto sistemático para o controle das correntes de entrada e da tensão de saída de retificadores PWM trifásicos. Primeiramente é apresentado o modelo discreto em eixos síncronos dq do retificador PWM trifásico com filtro de entrada L, o qual leva em conta o tempo de processamento necessário para a implementação em tempo real. A operação do retificador com resposta de tempo mínimo é obtida utilizando o método de desacoplamento por retroação de estados no domínio discreto, sem a necessidade de um controlador de corrente adicional no eixo d. Além disso, são desenvolvidos servos controladores de corrente e tensão a fim de garantir fator de deslocamento unitário e regulação de tensão no barramento CC respectivamente. Finalmente, resultados experimentais são apresentados, a fim de validar o procedimento proposto e verificar o desempenho do retificador PWM trifásico.This paper develops a systematic design procedure based on discrete decoupling by state feedback applied to three-phase PWM rectifiers. A discrete model for synchronous frame is developed for three-phase PWM rectifier with an L filter. This model takes into account the computational delays presents in the discrete implementation. Deadbeat response is obtaining without the requirement of a current controller in the axis d. Moreover, discrete servo controllers to ensure unit displacement power factor and regulated DC link voltage are developed. Finally, experimental results are presented to demonstrate the feasibility of the proposed procedure, algorithms and the performance of the overall system.

Robinson F. de Camargo

2005-12-01

169

Analysis of Harmonic Distortion by applying various PWM Techniques in Grid connected Photovoltaic Systems  

Directory of Open Access Journals (Sweden)

Full Text Available In the last decades, it has been observed that the harmonics distortions generated by the PV inverter are reduced by using Pulse with modulation technique. Harmonics reduction is the main consideration in three phase inductive load circuit.The performance of the three phase squirrel cage Induction motor was improved by the reduction of voltage harmonics and current harmonics. In this paper, the harmonic distortion of the three phase induction motor was measured in terms of THD by Simulation model and the results of the Multiple Pulse With Modulation and Sinusoidal Pulse With Modulation inputs were compared to find out the lowest THD value. By using the PWM technique on the Three Phase Induction motor there was reduction in the VTHD by 6. 98% and CTHD by 3.12%. By reducing the harmonics level we can increase the life time of motor, cables and capacitor.

1. K.Gurumoorthy,

2013-11-01

170

Analysis of voltage control for a self-excited induction generator using a current-controlled voltage source inverter (CC-VSI)  

Energy Technology Data Exchange (ETDEWEB)

The analysed results of both voltage regulation and current-harmonic suppression of a self- excited induction generator (SEIG), under unbalanced and/or nonlinear loading conditions using a current-controlled voltage source inverter (CC-VSI) are presented. A hybrid induction-machine model based on the three-phase a-b-c and the d-q frames of reference is employed to describe the dynamic performance of the studied system. The three-phase a-b-c induction-machine model is employed to derive dynamic equations of the SEIG under nonlinear loading conditions. The synchronously rotating reference frame based on a d-q axis model is used to decompose three-phase load currents into active and reactive power currents. The three-phase a-b-c stator voltages of the SEIG and the DC bus voltage of the inverter are simultaneously controlled by a proportional-integral (PI) voltage controller and a harmonic compensator. The simulated results show that the performance of the SEIG under unbalanced and/or nonlinear loading conditions has been effectively improved by the proposed compensating scheme. (Author)

Kuo, S. -C.; Wang, L. [Department of Electrical Engineering, National Cheng Kung University, 1 University Road, Tainan, Taiwan 70101 (China)

2001-09-01

171

One-Stage and Two-Stage Schemes of High Performance Synchronous PWM with Smooth Pulses-Ratio Changing  

DEFF Research Database (Denmark)

This paper presents detailed description of one-stage and two-stage schemes of a novel method of synchronous, pulsewidth modulation (PWM) for voltage source inverters for ac drive application. The proposed control functions provide accurate realization of different versions of voltage space vector modulation with synchronization of the voltage waveform of the inverter and with smooth pulse-ratio changing. Voltage spectra do not contain even harmonic and sub-harmonics (combined harmonics) during the whole control range including the zone of overmodulation. Examples of determination of the basic control parameters of the inverters with low switching frequency, as wel1 as results of its simulations, are presented.

Oleschuk, V.; Blaabjerg, Frede

2002-01-01

172

Optimizing three-phase planar transformer construction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A three-phase transformer with flat conductor layers is proposed in this article. This arrangement is used for high current density transformers. Cost effectiveness in planar magnetic are related with the optimization in the number of layers in each winding. This fact takes more relevance for the medium and high power three-phase transformers where the number of parallels to achieve the required DCR is increased. The proposed method allows the use of off-the-shell core shapes that are used fo...

Prieto Lo?pez, Roberto; Asensi Orosa, Rafael; Garci?a Sua?rez, Oscar; Cobos Ma?rquez, Jose? Antonio; Flavio David, Gerez

2012-01-01

173

Exposed high-voltage source effect on the potential of an ionospheric satellite  

Science.gov (United States)

A pulsed, high-voltage source, which is able to draw a current from the surrounding plasma, is seen to induce large changes in the potential of an ionospheric satellite (the Iowa Plasma Diagnostics Package flown on Space Shuttle flight STS-51F). This, in turn, may affect the operation of other instruments that use the chassis of the satellite as a ground for electrical circuits. The magnitude of the change in satellite potential is dependent upon both the orientation of the high-voltage source, relative to the plasma flow, and the characteristics of the high-voltage source. When the satellite is grounded to the Shuttle Orbiter, this effect is sufficient to change the potential of the Orbiter by a small, but noticeable, amount.

Tribble, A. C.; D'Angelo, N.; Murphy, G. B.; Pickett, J. S.; Steinberg, J. T.

1988-01-01

174

PWM Inverter control and the application thereof within electric vehicles  

Energy Technology Data Exchange (ETDEWEB)

An inverter (34) which provides power to an A.C. machine (28) is controlled by a circuit (36) employing PWM control strategy whereby A.C. power is supplied to the machine at a preselectable frequency and preselectable voltage. This is accomplished by the technique of waveform notching in which the shapes of the notches are varied to determine the average energy content of the overall waveform. Through this arrangement, the operational efficiency of the A.C. machine is optimized. The control circuit includes a micro-computer and memory element which receive various parametric inputs and calculate optimized machine control data signals therefrom. The control data is asynchronously loaded into the inverter through an intermediate buffer (38). In its preferred embodiment, the present invention is incorporated within an electric vehicle (10) employing a 144 VDC battery pack (32) and a three-phase induction motor (18).

Geppert, Steven (Bloomfield Hills, MI)

1982-01-01

175

Application of Discontinuous PWM Modulation in Active Power Filters  

DEFF Research Database (Denmark)

Classical discontinuous pulsewidth modulations (DPWMs) may not be efficiently applied in active power filters (APFs), because it is hard to predict the peak values of the inverter current, and consequently it is difficult to calculate the position of the clamped interval, that minimizes the switching losses in any operating point. This paper proposes a new DPWM strategy applied to shunt APFs. The proposed modulation strategy detects the current vector position relative to the inverter voltage reference and determines instantaneously the optimum clamped duration on each phase. It achieves a clamped voltage pattern, with variable lengths depending on the magnitude of the inverter current. This property adaptively reduces the current stress and minimizes the inverter switching losses, regardless of its application. The proposed modulation strategy is described, analyzed and validated on a three-phase voltage source inverter, rated at 7 kVA 400 V, controlled as an APF. Udgivelsesdato: July

Blaabjerg, Frede; Asiminoaei, Lucian

2008-01-01

176

Three-Phased Wake Vortex Decay  

Science.gov (United States)

A detailed parametric study is conducted that examines vortex decay within turbulent and stratified atmospheres. The study uses a large eddy simulation model to simulate the out-of-ground effect behavior of wake vortices due to their interaction with atmospheric turbulence and thermal stratification. This paper presents results from a parametric investigation and suggests improvements for existing fast-time wake prediction models. This paper also describes a three-phased decay for wake vortices. The third phase is characterized by a relatively slow rate of circulation decay, and is associated with the ringvortex stage that occurs following vortex linking. The three-phased decay is most prevalent for wakes imbedded within environments having low-turbulence and near-neutral stratification.

Proctor, Fred H.; Ahmad, Nashat N.; Switzer, George S.; LimonDuparcmeur, Fanny M.

2010-01-01

177

Three-Phase Shunt Active Power Filter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Active power filters have been widely used for harmonic elimination. The performance of a conventional three-phase shunt Active Power Filter (APF) using Synchronous Detection Method (SDM) has been compared with Nonlinear Autoregressive-Moving Average (NARMA)-L2 based APF. The novelty of this study lies in the application of NARMA-L2 control to generate the amplitude of the reference supply current required by the APF circuit and the successful implementation of the APF system for harmonic eli...

Moleykutty George; Basu, Kartik P.

2008-01-01

178

Three-phase Brushless DC Motor Control  

Digital Repository Infrastructure Vision for European Research (DRIVER)

With the increasing demand of using electric power and unpleasant of using brush motor; the usage of Three-phase Brushless Motor has been significantly developed in industry. However, with market-standard motor driver, there are many inconveniences for small institutions or companies in either application developments or education purposes. For instance, the size and the price of driver. Therefore, the object of this thesis was design modular sections (Software program, PCB driver and PCB con...

Fang, Xinwei

2012-01-01

179

Indirect current control with separate IZ drop compensation for voltage source converters  

Energy Technology Data Exchange (ETDEWEB)

Indirect Current Control (ICC) of boost type Voltage Source Converters (VSCs) using separate compensation of line IZ voltage drop is presented. A separate bi-directional VSC is used to produce the compensation voltage. This simplifies the ICC regulator scheme as the power flow is controlled through single modulation index. Experimental verification is provided for bi-directional control of the power flow.

Kanetkar, V.R. [Asea Brown Boveri Ltd., Vadodara (India). Corporate R and D; Dawande, M.S. [R.K.N. Engineering Coll., Nagpur (India). Dept. of Electrical Engineering; Dubey, G.K. [Indian Inst. of Tech., Kanpur (India). Dept. of Electrical Engineering

1995-12-31

180

Superconductor-metal transition in an ultrasmall Josephson junction biased by a noisy voltage source  

CERN Multimedia

Shot noise in a voltage source changes the character of the quantum (dissipative) phase transition in an ultrasmall Josephson junction: The superconductor-insulator transition transforms into the superconductor-metal transition. In the metallic phase the IV curve probes the voltage distribution generated by shot noise, whereas in the superconducting phase it probes the counting statistics of electrons traversing the noise junction.

Sonin, E B

2006-01-01

 
 
 
 
181

Performance Evaluation of Three Phase Bridge Module Type Diode Clamped Multilevel Inverter  

Directory of Open Access Journals (Sweden)

Full Text Available This work proposes three phase five level Bridge module type Diode Clamped Multilevel Inverter (DCMLI using various modulating techniques for induction motor load. These Pulse Width Modulating (PWM techniques include Carrier Overlapping (CO strategy, Variable Frequency (VF strategy, Phase Shift (PS strategy and Sub-Harmonic Pulse Width Modulation (SHPWM i.e. Phase Disposition (PD strategy, Phase Opposition Disposition (POD strategy and Alternate Phase Opposition Disposition (APOD strategy. The Total Harmonic Distortion (THD, VRMS (fundamental, crest factor, form factor and distortion factor are evaluated for various modulation indices. Simulation is performed using MATLAB-SIMULINK. It is observed thatPODPWM/PSPWM methods provide output with relatively low distortion for R Load. It is also observed that PSPWM method provides output with relatively low distortion for IM load. COPWM is also found to perform better since it provides relatively higher fundamental RMS output voltage for Induction Motor (IM load and R load.

C.R. Balamurugan, S. P. Natarajan, R.Bensraj

2012-06-01

182

Low-cost PWM speed controller for an electric mini-baja type vehicle  

Directory of Open Access Journals (Sweden)

Full Text Available This paperwork presents a Pulse Width Modulation (PWM speed controller for an electric mini-baja-type car. A battery-fed 1-kW three-phase induction motor provides the electric vehicle traction. The open-loop speed control is implemented with an equal voltage/frequency ratio, in order to maintain a constant amount of torque on all velocities. The PWM is implemented by a low-cost 8-bit microcontroller provided with optimized ROM charts for distinct speed value implementations, synchronized transition between different charts and reduced odd harmonics generation. This technique was implemented using a single passenger mini-baja vehicle, and the essays have shown that its application resulted on reduced current consumption, besides eliminating mechanical parts.

Samuel Euzédice de Lucena

2007-03-01

183

Low-cost PWM speed controller for an electric mini-baja type vehicle  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english This paperwork presents a Pulse Width Modulation (PWM) speed controller for an electric mini-baja-type car. A battery-fed 1-kW three-phase induction motor provides the electric vehicle traction. The open-loop speed control is implemented with an equal voltage/frequency ratio, in order to maintain a [...] constant amount of torque on all velocities. The PWM is implemented by a low-cost 8-bit microcontroller provided with optimized ROM charts for distinct speed value implementations, synchronized transition between different charts and reduced odd harmonics generation. This technique was implemented using a single passenger mini-baja vehicle, and the essays have shown that its application resulted on reduced current consumption, besides eliminating mechanical parts.

Samuel Euzédice de, Lucena; Márcio Abud, Marcelino; Francisco José, Grandinetti.

184

Methods, systems and apparatus for adjusting duty cycle of pulse width modulated (PWM) waveforms  

Science.gov (United States)

Embodiments of the present invention relate to methods, systems and apparatus for controlling operation of a multi-phase machine in a vector controlled motor drive system when the multi-phase machine operates in an overmodulation region. The disclosed embodiments provide a mechanism for adjusting a duty cycle of PWM waveforms so that the correct phase voltage command signals are applied at the angle transitions. This can reduce variations/errors in the phase voltage command signals applied to the multi-phase machine so that phase current may be properly regulated thus reducing current/torque oscillation, which can in turn improve machine efficiency and performance, as well as utilization of the DC voltage source.

Gallegos-Lopez, Gabriel; Kinoshita, Michael H; Ransom, Ray M; Perisic, Milun

2013-05-21

185

Metodologia de projeto de filtros de segunda ordem para inversores de tensão com modulação PWM digital  

Directory of Open Access Journals (Sweden)

Full Text Available Este artigo apresenta uma metodologia sistematizada de projeto de filtros de saída de segunda ordem para inversores que sintetizam tensões senoidais através de modulação por largura de pulso (PWM digital. O propósito desta metodologia é o de determinar os parâmetros do filtro que assegure a especificação da máxima taxa de distorção harmônica total (THD admissível nas tensões de saída do inversor PWM, para cargas lineares e não-lineares. A metodologia proposta é discutida em detalhes, incluindo a descrição das etapas necessárias para a derivação do procedimento de projeto para diferentes topologias de inversores de tensão e o procedimento para obtenção das curvas necessárias para o projeto. Finalizando, são apresentados alguns exemplos de projeto para topologias de inversores monofásicos e trifásicos com saída a três fios e a quatro fios. Resultados experimentais são apresentados para demonstrar a validade da metodologia de projeto proposta.This paper presents a systematized methodology of second-order output filter for inverters that synthesize sinusoidal voltage waveforms through digital pulse-width modulation (PWM. The objective of this methodology is to determine the largest corner frequency of the filter that ensure the specification of the maximum total harmonic distortion (THD admissible in the output voltages of the PWM inverter, for linear and non-linear loads. The proposed methodology is discussed in detail, including the description of the required steps for the derivation of the design procedure for different topologies of voltage inverters and the procedure to obtain the design curve. Finally, it is presented some design examples for single-phase, three-phase three-wire and three-phase four-wire filters topologies. Experimental results have been provided to demonstrate the validity of the proposed design methodology.

Leandro Michels

2005-06-01

186

Three phase superconducting armature: Windings and cryostat  

International Nuclear Information System (INIS)

The existence of superconducting wires with reduced losses under AC magnetic fields allows to design AC Machines using superconducting coils for both field and armature windings. A superconduction armature needs new materials and new concepts for the windings and the cryostat: Glass fiber reinforced epoxy structure; Non impregnated superconducting windings; Low losses horizontal cryostat. The paper presents a cryostat designed to receive a three phase superconducting winding as to form, with a superconducting field winding rotor, a 20 kVa synchronous machine. Construction and preliminary test on the cryostat and the windings are reported

1986-01-01

187

An Algorithm for Applying Multiple Currents Using Voltage Sources in Electrical Impedance Tomography.  

Science.gov (United States)

A method to produce a desired current pattern in a multiple-source EIT system using voltage sources is presented. Application of current patterns to a body is known to be superior to the application of voltage patterns in terms of high spatial frequency noise suppression, resulting in high accuracy in conductivity and permittivity images. Since current sources are difficult and expensive to build, the use of voltage sources to apply the current pattern is desirable. An iterative algorithm presented in this paper generates the necessary voltage pattern that will produce the desired current pattern. The convergence of the algorithm is shown under the condition that the estimation error of the linear mapping matrix from voltage to current is small. Simulation results are presented to illustrate the convergence of the output current. PMID:20463914

Choi, Myoung H; Kao, Tzu-Jen; Isaacson, David; Saulnier, Gary J; Newell, Jonathan C

2008-01-01

188

The Investigation of Sinusoidal Single Phase Voltage Source Inverter Output Filter  

Directory of Open Access Journals (Sweden)

Full Text Available The results of output filter investigation of single phase sine voltage source inverter (VSI are presented. The operating principle, construction and a most widely used topology of single phase voltage source inverter is discussed. The results obtained using modeling and experimental investigation are presented. The Total Harmonic Distortion of the inverter output voltage and maximal current of the output capacitor were analyzed using Matlab Simulink software. The 1 kW inverter prototype was built for experimental investigation. The inverter switches are realized using IGBT transistors. The toroidal iron powder core with distributed air gap was used as the core of the inductor. The experimental investigation of inductor core losses and maximal current of output filter capacitor were performed.Article in Lithuanian

Andrius Platakis

2011-08-01

189

Elimination of the waveform distortions in the voltage-source-converter type matrix converter  

Energy Technology Data Exchange (ETDEWEB)

The recently reported voltage-source-converter type matrix converter offers advantages in terms of employing the well-known and proven technology of the 3-phase voltage-source converters, bypassing the switching difficulties associated with the bidirectional switches in the conventional 9-switch matrix converter topology, and reduction in the conduction losses. The new matrix converter topology is capable of establishing the dual condition of Unity Displacement Power Factor on the utility-side and Field Vector Control on the motor load-side. However, because of the special structure of the transformation matrix and the presence of dc components in the side-2 voltages, the branch currents on side-1 and the ac voltages on side-2 contain some unwanted components resulting in additional losses and waveform distortions. This paper addresses the above problem and proposes a novel technique for the elimination of the unwanted components. Experimental results are used to verify the correctness of the theoretical expectations.

Ooi, B.T.; Kazerani, M. [McGill Univ., Montreal, Quebec (Canada). Dept. of Electrical Engineering

1995-12-31

190

Cross connected multilevel voltage source inverter topologies for medium voltage applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Multilevel voltage source inverters where first introduced in the early 1980s. Since then, they have been continuously developed, offering a wide new research area in power electronics. The popularity of multilevel solutions come from the advantages that they offer: improved output quality, voltage sharing in high voltage applications, increased power density or reduction of filtering costs. Two completely new and innovative cross-connected topological families for advanced multilevel voltage...

2008-01-01

191

Frequency Coupling in Inverter Grids Modeling the Mutual Interference of Voltage Source Inverters in Island Grids  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a model to describe the mutual frequency disturbance of meshed and interconnected voltage source inverters during transient phases. The model provides a weighted mutual frequency coupling matrix taking into account that the mutual frequency measurement disturbance decreases for increasing electric distance between the inverters (i.e. depend on the line admittance) and depends on the respective inverter’s rated power, meaning that stronger inverters have more influence th...

Jostock, Markus; Sachau, Ju?rgen

2012-01-01

192

The Initial Parameters Design of the Voltage Source Converter Fed SMES  

Directory of Open Access Journals (Sweden)

Full Text Available The initial parameters of the superconducting magnetic energy storage (SMES fed by a voltage source converter (VSMES are studied and the setting rules are designed in this paper. A time-domain simulation model is established by using the software PSCAD/EMTDC. Based on this model, the application of the VSMES in the power system is used to test the designed rules. The simulation results are valuable for the further research of the initial parameters design of the VSMES.

Xudong Song

2010-08-01

193

Performance Analysis of a Voltage Source Converter (VSC) based HVDC Transmission System under Faulted Conditions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Voltage Source Converter (VSC) based HVDC transmission technology hasbeen selected as the basis for several recent projects due to its controllability,compact modular design, ease of system interface, and low environmentalimpact. This paper investigates the dynamic performance of a 200MW,±100kV VSC-HVDC transmission system under some faulted conditionsusing MATLAB/Simulink. Simulation results confirm the satisfactoryperformance of the proposed system under active and reactive powervariations...

2009-01-01

194

Performance Analysis of a Voltage Source Converter (VSC based HVDC Transmission System under Faulted Conditions  

Directory of Open Access Journals (Sweden)

Full Text Available Voltage Source Converter (VSC based HVDC transmission technology hasbeen selected as the basis for several recent projects due to its controllability,compact modular design, ease of system interface, and low environmentalimpact. This paper investigates the dynamic performance of a 200MW,±100kV VSC-HVDC transmission system under some faulted conditionsusing MATLAB/Simulink. Simulation results confirm the satisfactoryperformance of the proposed system under active and reactive powervariations and fault conditions.

Amiri RABIE

2009-12-01

195

Variable speed wind turbine generator system with current controlled voltage source inverter  

International Nuclear Information System (INIS)

highlights: ? Current controlled voltage source inverter scheme for wind power application. ? Low voltage ride through of wind farm. ? 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.

2011-07-01

196

Three-Phase Shunt Active Power Filter  

Directory of Open Access Journals (Sweden)

Full Text Available Active power filters have been widely used for harmonic elimination. The performance of a conventional three-phase shunt Active Power Filter (APF using Synchronous Detection Method (SDM has been compared with Nonlinear Autoregressive-Moving Average (NARMA-L2 based APF. The novelty of this study lies in the application of NARMA-L2 control to generate the amplitude of the reference supply current required by the APF circuit and the successful implementation of the APF system for harmonic elimination. The entire system has been modeled using MATLAB 6.1 toolbox. Simulation results demonstrate the applicability of NARMA-L2 controller for the control of APF.

Moleykutty George

2008-01-01

197

Three Phase to Three Phase Direct Matrix Converter using SPWM Technique  

Directory of Open Access Journals (Sweden)

Full Text Available The principle of three phase SPWM AC-AC matrix converter using 9 bidirectional switching devices is explained. IGBT-power diode combination is used is main power switching device. Constant voltage and frequency sinusoidal supply voltage can be converted to variable voltage and frequency voltage using this converter. The working is described based on the working three phase to single phase matrix converter. MATLAB/ Simulink software is used for the simulation. The operation is analyzed for various modulation indexes and input voltages. The results are compared and the optimum condition for favorable operation is obtained.

Sharon D. Ronald,

2013-05-01

198

Análise e implementação de retificadores PWM trifásicos com resposta de tempo mínimo utilizando desacoplamento por retroação de estados  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Este trabalho desenvolve um procedimento de projeto sistemático para o controle das correntes de entrada e da tensão de saída de retificadores PWM trifásicos. Primeiramente é apresentado o modelo discreto em eixos síncronos dq do retificador PWM trifásico com filtro de entrada L, o qual leva em cont [...] a o tempo de processamento necessário para a implementação em tempo real. A operação do retificador com resposta de tempo mínimo é obtida utilizando o método de desacoplamento por retroação de estados no domínio discreto, sem a necessidade de um controlador de corrente adicional no eixo d. Além disso, são desenvolvidos servos controladores de corrente e tensão a fim de garantir fator de deslocamento unitário e regulação de tensão no barramento CC respectivamente. Finalmente, resultados experimentais são apresentados, a fim de validar o procedimento proposto e verificar o desempenho do retificador PWM trifásico. Abstract in english This paper develops a systematic design procedure based on discrete decoupling by state feedback applied to three-phase PWM rectifiers. A discrete model for synchronous frame is developed for three-phase PWM rectifier with an L filter. This model takes into account the computational delays presents [...] in the discrete implementation. Deadbeat response is obtaining without the requirement of a current controller in the axis d. Moreover, discrete servo controllers to ensure unit displacement power factor and regulated DC link voltage are developed. Finally, experimental results are presented to demonstrate the feasibility of the proposed procedure, algorithms and the performance of the overall system.

Camargo, Robinson F. de; Botterón, Fernando; Duarte, Marcelo Hey; Marques, Jéferson; Pinheiro, Humberto.

199

Direct-current vector control of three-phase grid-connected rectifier-inverter  

Energy Technology Data Exchange (ETDEWEB)

The three-phase grid-connected converter is widely used in renewable and electric power system applications. Traditionally, control of the three-phase grid-connected converter is based on the standard decoupled d-q vector control mechanism. Nevertheless, the study of this paper shows that there is a limitation in the conventional standard vector control method. Some of the limitations have also been found recently by other researchers. To overcome the shortage of the conventional vector control technique, this paper proposes a new direct-current d-q vector control mechanism in a nested-loop control structure, based on which an optimal control strategy is developed in a nonlinear programming formulation. The behaviors of both the conventional and proposed control methods are compared and evaluated in simulation and laboratory hardware experiment environments, both of which demonstrates that the proposed approach is effective for grid-connected power converter control in a wide system conditions while the conventional standard vector control approach may behave improperly especially when the converter operates beyond its PWM saturation limit. (author)

Li, Shuhui; Haskew, Timothy A.; Hong, Yang-Ki; Xu, Ling [Department of Electrical and Computer Engineering, University of Alabama, Tuscaloosa, AL 35475 (United States)

2011-02-15

200

Cascaded Multilevel Inverter with PWM Control Method  

Directory of Open Access Journals (Sweden)

Full Text Available A hybrid cascaded multilevel inverter with PWM method is presented in this paper. It consists of a standard 3-leg inverter (one leg for each phase and Hbridge in series with each inverter leg. It can use only a single DC power source to supply a standard 3-leg inverter along with three full H-bridges supplied by capacitors. Multilevel carrier- based PWM method is used to produce a five-level phase voltage. The inverter can be used in hybrid electric vehicles (HEV and electric vehicles (EV. A simulation model based on PSIM and MATLAB/SIMULINK is developed. An experimental 5 kW prototype inverter is built and tested. The results experimentally validate the proposed PWM hybrid cascaded multilevel inverter.

M.Kiran Kumar #1 , M.Saikiran *2 , Ch.Venkateswarlu

2013-05-01

 
 
 
 
201

Bi-directional Three-phase Current-Source PWM Inverter Introducing Zero-Current Soft-Switching Technique  

Science.gov (United States)

Although power semiconductor devices such as IGBTs and GTOs have been widely used for high power industrial applications, turn-off losses of those devices due to the current tail characteristics dominate their total switching losses. A soft switching technique is very effective in cutting down the switching losses. We have proposed an energy storage system using a current-source inverter (CSI) and a zero-current switching bi-directional DC-DC converter with a simple L-C resonant circuit in our previous works. However, based on those works, the CSI circuit is turned on and off with a hard switching technique. Improvements of efficiency and performance of CSI are indispensable to implement the proposed system. This paper proposed a soft-switching bi-directional circuit topology. The switching losses of CSI are reduced by adding a commutation circuit. In order to verify effectiveness of the proposed system, the system is analyzed in terms of the characteristics of switching losses and conversion efficiency, through a theoretical approach and computer simulations based on an instantaneous value analysis model.

Kinjyo, Tatsuto; Senjyu, Tomonobu; Urasaki, Naomitsu; Fujita, Hideki

202

A hyperbolic three-phase flow model  

International Nuclear Information System (INIS)

Some applications in the nuclear power energy and petroleum engineering require modelling of three phase flows, either in a one dimensional or in a three dimensional framework. In order to compute unsteady flows in an expected meaningful way, and especially when one aims at predicting phenomena such as the boiling crisis, or the loss of primary coolant accidents, or any other severe situation, one needs to handle well posed initial value problems. Since single pressure models may fail in many situations, when one refines the mesh size, owing to the loss of hyperbolicity, we propose herein a class of hyperbolic models to deal with this kind of flows. The model ensures that void fractions, mass fractions and pressures remain positive through single waves occurring in the one dimensional solution of the Riemann problem. The basic ideas rely on the counterpart of the two-phase two-pressure formalism which is now quite well-known. One of the main difficulties here is to define correct interfacial transfer terms, in such a way that for physically relevant initial conditions, smooth solutions but also discontinuous solutions are correctly defined, and remain in their physical domain. Another goal consists in getting a physically admissible entropy condition to keep the whole under control. An - obviously compulsory - underlying assumption in the model is that the interface should remain thin in the convective process. This corresponds to the fact that the field associated with the eigenvalue Vi should be linearly degenerated. Though some non-conservative terms are present in the system, the internal structure of fields will be such that non-conservative products are well defined

2006-05-01

203

Design, Control, and Modeling of a New Voltage Source Converter for HVDC System  

Science.gov (United States)

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 (?), 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.

Mohan, Madhan; Singh, Bhim; Ketan Panigrahi, Bijaya

2013-05-01

204

Power system damping from energy function analysis implemented by voltage-source-converter stations  

Energy Technology Data Exchange (ETDEWEB)

Because weakly damped system oscillations can endanger the secure operation of power systems, this paper is a study on how damping can be increased. As the power system is nonlinear, an energy function approach, patterned after the direct method of Lyapunov function, is used in the analysis. The analysis develops an energy function W and shows that a real power term (proportional to local frequency) and/or a reactive power term (proportional to the line voltage differentiated with respect to time) increase the rate of diminution of the energy function W. This implies effective damping of power swings by such power signals and is verified by simulations of a multi-machine system model. The damping signals are introduced by voltage-source-converter (VSC) stations. (author)

Ruan, Si-Ye; Li, Guo-Jie; Sun, Yuan-Zhang [State Key Laboratory of Power Systems, Department of Electrical Engineering, Tsinghua University, Beijing, 100084 (China); Ooi, Boon-Teck [Department of Electrical and Computer Engineering, McGill University, Montreal, QC H3A 2A7 (Canada)

2008-08-15

205

Power Control of New Wind Power Generation System with Induction Generator Excited by Voltage Source Converter  

Science.gov (United States)

This paper investigates advantages of new combination of the induction generator for wind power and the power electronic equipment. Induction generator is popularly used for the wind power generation. The disadvantage of it is impossible to generate power at the lower rotor speed than the synchronous speed. To compensate this disadvantage, expensive synchronous generator with the permanent magnets is sometimes used. In proposed scheme, the diode rectifier is used to convert the real power from the induction generator to the intermediate dc voltage, while only the reactive power necessary to excite the induction generator is supplied from the voltage source converter (VSC). This means that the rating of the expensive VSC is minimized and total cost of the wind power generation system is decreased compared to the system with synchronous generator. Simulation study to investigate the control strategy of proposed system is performed. The results show the reduction of the VSC rating is prospective.

Morizane, Toshimitsu; Kimura, Noriyuki; Taniguchi, Katsunori

206

Transient operation of grid-connected voltage source converter under unbalanced voltage conditions  

Energy Technology Data Exchange (ETDEWEB)

In this paper, the operation of shunt-connected Voltage Source Converters under unbalanced voltage conditions is investigated. The attention focuses on voltage dips, thus on transient operation. The importance of using a fast and accurate method for detection of sequence components of the grid voltage affected by a fault is emphasized. Four different sequence-detection techniques are presented and compared on the basis of their transient response. Three different current controllers for VSC are implemented and compared in both cases of constant and regulated dc-link voltage. In the latter case, the corresponding dc-link voltage controllers are described. The operation of the VSC equipped with the different current controllers is analyzed with constant-power and fluctuating-power loads. Results obtained with different type of loads demonstrate that the optimal choice of the controller depends on the expected application.

Saccomando, G.; Svensson, Jan

2001-07-01

207

Selective Harmonic Virtual Impedance for Voltage Source Inverters with LCL filter in Microgrids  

DEFF Research Database (Denmark)

This paper presents a new control approach for voltage source inverters ended with LCL filters for microgrid applications. The control approach consists of voltage and current inner control loops in order to fix the filter capacitor voltage and a virtual impedance loop. The virtual impedance is added in order to mitigate the voltage distortion after the output inductor and improve the load sharing among parallel inverters. A general case with a combined voltage harmonic and unbalance distortion is considered. In such a case, voltage distortion is mitigated by inserting capacitive virtual impedance for negative sequence of fundamental component as well as positive and negative sequences of main harmonic components. Furthermore, resistive virtual impedances are added at these components in order to provide a proper load sharing and make the overall system more damped. Simulation results are presented to demonstrate the effectiveness of the proposed control approach.

Savaghebi, Mehdi; Vasquez, Juan Carlos

2012-01-01

208

A Consideration of Stable Operating Power Limits of HVDC System Composed of Voltage Source Converters  

Science.gov (United States)

The stable operating power limits of a small scale HVDC system composed of voltage source converters (VSC-HVDC system) are analyzed with a simple model. The VSC-HVDC system could operate where the AC system must be somewhat larger in capacity than the VSC-HVDC system capacity. The stable operating power limits were between one and two times the SCR (short circuit ratio). When the inverter of the VSC-HVDC system was operated with lead reactive (capacitive) power control conditions, the stable operating limits were increased through AC voltage stabilization. When the inverter was a STATCOM operation, it could operate regardless of the SCR but regions within allowable AC voltage variations.

Konishi, Hiroo; Takahashi, Choei; Kishibe, Hideto; Sato, Hiromichi

209

A Flexible Dynamic Control Strategy of Full Power Voltage Source Inverter Based on Brochistos Chronos  

Directory of Open Access Journals (Sweden)

Full Text Available Nowadays, there are several renewable power sources connected into power grid with full power Voltage Source Inverter (VSI, such as photovoltaic power system and variable speed wind turbines. The operation state variables of full power VSI should be adjusted seamlessly in order to reduce the fluctuation of output power. The current linearization control strategy leads a certain extent impact component during the dynamic motion process. This study present the Brochistos Chronos Control Strategy (BCCS based on Hamilton theory, with the flexibility of full power VSI system, the smoothness and promptness is reflected in integrated process by the way of regulates state variables precisely. The effectiveness of this control strategy is be verified by the simulation results and the overall process fulfill the requirements of the duration as short as possible.

Tian Yizhi

2013-01-01

210

A low-power circuit for piezoelectric vibration control by synchronized switching on voltage sources  

CERN Document Server

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.

Shen, Hui; Ji, Hongli; Zhu, Kongjun; Balsi, Marco; Giorgio, Ivan; dell'Isola, Francesco

2010-01-01

211

A very low noise, high accuracy, programmable voltage source for low frequency noise measurements  

Science.gov (United States)

In this paper an approach for designing a programmable, very low noise, high accuracy voltage source for biasing devices under test in low frequency noise measurements is proposed. The core of the system is a supercapacitor based two pole low pass filter used for filtering out the noise produced by a standard DA converter down to 100 mHz with an attenuation in excess of 40 dB. The high leakage current of the supercapacitors, however, introduces large DC errors that need to be compensated in order to obtain high accuracy as well as very low output noise. To this end, a proper circuit topology has been developed that allows to considerably reduce the effect of the supercapacitor leakage current on the DC response of the system while maintaining a very low level of output noise. With a proper design an output noise as low as the equivalent input voltage noise of the OP27 operational amplifier, used as the output buffer of the system, can be obtained with DC accuracies better that 0.05% up to the maximum output of 8 V. The expected performances of the proposed voltage source have been confirmed both by means of SPICE simulations and by means of measurements on actual prototypes. Turn on and stabilization times for the system are of the order of a few hundred seconds. These times are fully compatible with noise measurements down to 100 mHz, since measurement times of the order of several tens of minutes are required in any case in order to reduce the statistical error in the measured spectra down to an acceptable level.

Scandurra, Graziella; Giusi, Gino; Ciofi, Carmine

2014-04-01

212

Control de un rectificador PWM con funciones ampliadas basado en un procesador digital de señales / Control of a PWM Rectifier with Extended Functions in a Signal Digital Processor  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish Este trabajo presenta la aplicación de un procesador digital de señales (DSP) para el control de un rectificador PWM trifásico para aplicaciones industriales, al cual se le amplían sus funciones para tener capacidad de compensar caídas de voltaje instantáneas. El estudio resalta las ventajas que ofr [...] ece el DSP para controlar el rectificador haciendo uso de la transformación del sistema de un marco de referencia fijo a uno síncrono (teoría D-Q) y controladores clásicos. Se presenta el análisis del sistema, así como resultados de simulación y experimentales para validar la operación del DSP como elemento controlador del sistema. Abstract in english This work presents the application of a digital signal processor (DSP) for the control of a three-phase PWM rectifier for industrial applications, to which are extended their functions to have capacity to compensate voltage sags. The study stands out the advantages that the DSP offers to control, ba [...] sed on the system transformation from fix reference frame to synchronous reference frame (D-Q theory) and classical controllers. The analysis of the system is presented, as well as simulation and experimental results to validate the operation of the DSP as system element controller.

Núñez-Gutiérrez, C; Lira-Pérez, J; Cárdenas-Galindo, V.M.; Alvarez-Salas, R.

213

Output stages inside a negative feedback loop: application to a low-voltage three-phase DC-AC converter for educational purposes  

CERN Document Server

The circuit presented in this paper aims at providing three 40 Vpp 50Hz AC voltages sources with 120-degree phase separation between them. This is a fully analogue circuit that uses standard, low-cost electronic components without resorting to a microcontroller as previously proposed by Shirvasar et al [1]. This circuit may serve as a basis for a low-voltage 3P-AC power supply that students may safely use to realize experiments, i.e. about the principles and applications of three-phase AC power lines, without the risk of electric shocks.

Llopis, Francisco

2013-01-01

214

A Three-Phase Dual-Input Matrix Converter for Grid Integration of Two AC Type Energy Resources  

DEFF Research Database (Denmark)

This paper proposes a novel dual-input matrix converter (DIMC) to integrate two three-phase ac type energy resources to a power grid. The proposed matrix converter is developed based on the traditional indirect matrix converter under reverse power flow operation mode, but with its six-switch voltage source converter replaced by a nine-switch configuration. With the additional three switches, the proposed DIMC can provide six in put terminals, which make it possible to integrate two independent ac sources into a single grid-tied power electronics interface. The proposed converter has input-to-output voltage boost capability since power flows from the converterâ??s voltage source side to its current source side. Commanded currents can be extracted from the two input sources to the grid. The proposed control and modulation schemes guarantee sinusoidal input and output waveforms as well as unity input power factors. The simulation and experimental results using a laboratory prototype are provided to validate the effectiveness of the proposed control and modulation schemes for the proposed converter.

Liu, Xiong; Wang, Peng

2013-01-01

215

Rotor cage fault diagnosis in three-phase induction motors based on a current and virtual flux approach  

International Nuclear Information System (INIS)

This paper focuses on the detection of a rotor cage fault in a three-phase PWM feed induction motor. In inverter-fed machines there are some difficulties for the detection of a rotor cage fault. These difficulties are due to the fault signature that will be contained in the currents or voltages applied to the machine. In this way, a new approach based on the current and a virtual flux is proposed. The use of the virtual flux allows the improving of the signal to noise ratio. This approach also allows the identification of a rotor cage fault independently of the type of control used in the ac drive. The theoretical principle of this method is discussed. Simulation and experimental results are presented in order to show the effectiveness of the proposed approach

2009-04-01

216

Three Phase Two Leg Neutral Point Clamped Converter with output DC Voltage Regulation and Input Power Factor Correction  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, a three-phase two leg neutral point clamped (NPC converter is presented for power factor correction and dc-link voltage regulation. The adopted converter has simpler circuit configuration and less number of power switches compared to three-level PWM converter. In this circuit configuration, only eight power switches and four clamping diodes with voltage stress of half the dc bus voltage are used. A simplified space vector pulse width modulation scheme (SVPWM is also adopted to track the line current commands. A reference voltage vector is generated on the ac terminal for drawing the sinusoidal line currents with unity power factor. This algorithm reduces the time required to calculate the switching time durations of voltage vectors. The simulation results have been presented to verify the validity and effectiveness of the proposed control strategy.

Bogimi Sirisha

2012-03-01

217

A COMPARATIVE STUDY OF PROPORTIONAL INTEGRAL CONTROLLER AND FUZZY LOGIC CONTROLLER IN SCALAR SPEED CONTROL OF THREE PHASE INDUCTION MOTOR  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a performance study of the proportionalintegral controller andthe fuzzy logic controller in scalar speed control of three phase squirrel cage induction motor drive. Here the speed control is possible by varying supply frequencyusing a voltage source inverter while keeping voltage to frequency ratio as a constant. Speed error is given as inputto the proportional integral controller, and speed error and change in speed error are given as input to the fuzzy logic controller.The controller output controls the reference of sinusoidal pulse width modulation. Hence, the fundamental frequency and fundamental voltage of inverter output can be varied to control the motor speed.The performance of proportional integral controller and fuzzy logic controller underload torqueand reference speed variationisevaluated by simulation results in Simulink.

SAFDAR FASAL T K, UNNIKRISHNAN L

2013-07-01

218

An electronic solution for the direct connection of a three-phase induction generator to a single-phase feeder  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Este artigo propõe uma solução para a conexão direta de geradores de indução trifásicos em uma rede monofásica com regulação de vazão o que faz com que, a velocidade do gerador de indução se mantenha acima de sua velocidade síncrona. Para que a conexão entre gerador e rede monofásica seja satisfatór [...] ia e para que os critérios de qualidade de energia sejam preservados, o controle do fluxo de energia, entre a rede monofásica e o conversor PWM trifásico, é realizado empregando a idéia de sistema interligado ajustando a defasagem e amplitude da tensão sintetizada pelo conversor em relação a tensão da rede monofásica de forma que o fator de potência na rede monofásica seja unitário. Em relação ao conversor de potência, espera-se que o mesmo produza tensões senoidais, com freqüência e amplitude fixas para que o gerador de indução opere balanceado. O artigo descreve a estratégia de controle do inversor, o critério de projeto dos controladores e apresenta alguns resultados experimentais. Abstract in english This paper proposes a solution for the direct connection of a three-phase induction generator to a single-phase feeder. This high power quality system is intended to be used in micro-hydro power plants applications with control of the water flow. It is employed to maintain the speed of the induction [...] generator greater than its synchronous value. The difference between the generated power and the power consumed by the local load flows through the single-phase feeder. The power flow control is provided by a three-phase PWM inverter that additionally guarantees the local power quality. A system with good power quality must have sinusoidal and constant amplitude voltages, fixed frequency operation, balanced induction generator voltages and currents, harmonics and reactive power compensation. The paper describes the inverter control strategy, presents design criteria of the controllers, and shows experimental results.

Machado, Ricardo Q.; Gonçalves, Amílcar F. Q.; Buso, Simone; Pomilio, José A..

219

An electronic solution for the direct connection of a three-phase induction generator to a single-phase feeder  

Directory of Open Access Journals (Sweden)

Full Text Available This paper proposes a solution for the direct connection of a three-phase induction generator to a single-phase feeder. This high power quality system is intended to be used in micro-hydro power plants applications with control of the water flow. It is employed to maintain the speed of the induction generator greater than its synchronous value. The difference between the generated power and the power consumed by the local load flows through the single-phase feeder. The power flow control is provided by a three-phase PWM inverter that additionally guarantees the local power quality. A system with good power quality must have sinusoidal and constant amplitude voltages, fixed frequency operation, balanced induction generator voltages and currents, harmonics and reactive power compensation. The paper describes the inverter control strategy, presents design criteria of the controllers, and shows experimental results.Este artigo propõe uma solução para a conexão direta de geradores de indução trifásicos em uma rede monofásica com regulação de vazão o que faz com que, a velocidade do gerador de indução se mantenha acima de sua velocidade síncrona. Para que a conexão entre gerador e rede monofásica seja satisfatória e para que os critérios de qualidade de energia sejam preservados, o controle do fluxo de energia, entre a rede monofásica e o conversor PWM trifásico, é realizado empregando a idéia de sistema interligado ajustando a defasagem e amplitude da tensão sintetizada pelo conversor em relação a tensão da rede monofásica de forma que o fator de potência na rede monofásica seja unitário. Em relação ao conversor de potência, espera-se que o mesmo produza tensões senoidais, com freqüência e amplitude fixas para que o gerador de indução opere balanceado. O artigo descreve a estratégia de controle do inversor, o critério de projeto dos controladores e apresenta alguns resultados experimentais.

Ricardo Q. Machado

2009-09-01

220

A New Topology of Three-Phase Four-Wire UPQC with a Simplified Control Algorithm  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, a simplified control algorithm based on unit vector template generation (UVTG is proposed for a star-delta supported three-phase four-wire (3P-4W unified power quality conditioner (UPQC topology for the improvement of different power quality problems. Different topologies reported in literature for 3P-4W UPQC use active compensation for the mitigation of source neutral current along with other power quality (PQ problems, while the uses of passive elements for the mitigation of source neutral current are advantageous over the active compensation due to ruggedness and less complexity of control. Hence, in this paper a star-delta transformer is connected in shunt near the load for mitigation of source neutral current, while three-leg voltage source inverters (VSIs based shunt and series active power filters (APFs of 3P-4W UPQC mitigate the current and voltage based distortions, respectively. A simple control algorithm based on Unit Vector Template Generation (UVTG is used as a control strategy of UPQC for mitigation of different PQ problems. In this control scheme, the current/voltage control is applied over the fundamental supply currents/load voltages instead of fast changing APFs currents/voltages, thereby reducing the effects of computational delay and the required sensors. The performance of the proposed topology of UPQC is analyzed through simulations results using MATLAB software with its Simulink and Power System Block set toolboxes.

Yash Pal

2012-03-01

 
 
 
 
221

Inclusion of a high voltage DC-voltage source converter model in a Newton-Raphson power flow algorithm  

Energy Technology Data Exchange (ETDEWEB)

Models for high voltage DC-voltage source converter (HVDC-VSC) controllers suitable for direct incorporation into Newton-Raphson power flow algorithms are presented. The models are developed from first principles, starting with a simple VSC model and progressing to encompass the full HVDC-VSC link model. The applied modelling approach is modular in nature and in addition to the shunt-connected voltage source model, which may be used to represent a STATCOM, a series-connected voltage source model is also developed. This enables significant modelling flexibility since by suitably combining shunt and/or series voltage sources several VSC-based flexible AC transmission system (FACTS) controller models are realised quite straightforwardly, namely the back-to-back HVDC-VSC, the full HVDC-VSC link and the unified power flow controller. Attention is focused on the HVDC-VSC models. The models are implemented into an existing OOP power flow computer program written in C++ that incorporates a wide portfolio of FACTS models. The models are tested for reliability towards the convergence and accuracy of results using several power systems with varying degrees of operational complexity and power flow control requirements (Author)

Angeles-Camacho, C.; Acha, E. [Glasgow Univ., Dept. of Electronics and Electrical Engineering, Glasgow (United Kingdom); Tortelli, O.L. [Federal Univ. of Parana, Dept. of Electrical Engineering, Curitiba, PR (Brazil); Fuerte-Esquivel, C.R. [U.M.S.N.H., Div. de Estudios de Posgrado Cuidad Univ., Facultad de Ingenieria Electrica, San Nicolas de Hidalgo (Mexico)

2003-11-01

222

An improved fault-tolerant control scheme for PWM inverter-fed induction motor-based EVs.  

Science.gov (United States)

This paper proposes an improved fault-tolerant control scheme for PWM inverter-fed induction motor-based electric vehicles. The proposed strategy deals with power switch (IGBTs) failures mitigation within a reconfigurable induction motor control. To increase the vehicle powertrain reliability regarding IGBT open-circuit failures, 4-wire and 4-leg PWM inverter topologies are investigated and their performances discussed in a vehicle context. The proposed fault-tolerant topologies require only minimum hardware modifications to the conventional off-the-shelf six-switch three-phase drive, mitigating the IGBTs failures by specific inverter control. Indeed, the two topologies exploit the induction motor neutral accessibility for fault-tolerant purposes. The 4-wire topology uses then classical hysteresis controllers to account for the IGBT failures. The 4-leg topology, meanwhile, uses a specific 3D space vector PWM to handle vehicle requirements in terms of size (DC bus capacitors) and cost (IGBTs number). Experiments on an induction motor drive and simulations on an electric vehicle are carried-out using a European urban driving cycle to show that the proposed fault-tolerant control approach is effective and provides a simple configuration with high performance in terms of speed and torque responses. PMID:23916869

Tabbache, Bekheïra; Benbouzid, Mohamed; Kheloui, Abdelaziz; Bourgeot, Jean-Matthieu; Mamoune, Abdeslam

2013-11-01

223

Research on coordinate transformation of the three-phase circuit  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The different three-phase circuit coordinate transformation matrixes are given in relevant literatures , which may cause some difficulties to understand and apply the coordinate transformation. The paper presents a general expression of the coordinate transformation matrixes in three-phase circuit and points out that the coordinate transformation matrixes having different specific expressions are due to existing the parameters which can be selected in the general expression. On this basis, th...

Tian Ming Xing; yan hong; Yuan Dong Sheng

2013-01-01

224

Harmonic Filtering Performance of a Hybrid Active Filter for a Three-Phase 12-Pulse Diode Rectifier  

Science.gov (United States)

This paper describes a hybrid active filter for harmonic-current compensation of a three-phase 12-pulse diode rectifier used as the front end of a medium-voltage motor drive system. This hybrid filter is characterized by the direct series connection of a simple LC filter and a small-rated active filter. This circuit configuration brings low cost, small size, and light weight to the hybrid filter. The authors design, construct, and test a three-phase experimental system rated at 400V and 15kW, which is a downscaled model of the medium-voltage motor drive system. In this experiment, the LC filter is tuned to the 11th harmonic frequency, and the active filter is based on a three-level diode-clamped PWM converter with a dc capacitor voltage as low as 28V. This hybrid filter is connected on either the first or fourth winding of a line-frequency transformer with a first ?-winding voltage of 400V in the primary, and a second ?-winding voltage of 220V, a third Y-winding voltage of 220V, and a fourth ?-winding voltage of 400V in the secondary. Experimental results show that the hybrid filter performs satisfactory filtering in a range from the no-load to full-load conditions.

Isozaki, Kohei; Akagi, Hirofumi

225

A new current controller for PWM converters  

Energy Technology Data Exchange (ETDEWEB)

From the cost-effective product point of view, it is very important to design a new current controller with the highest utilization factor of current capacity of power devices. This paper deals with a state-deadbeat current controller for PWM converters, which shows the fastest current control response without overshoot irrespective of the saturation of control voltage. No-overshoot control response means that the current capacity could be fully utilized in the control sense. Simulation results done by Matlab`s Simulink show good current control characteristics. (author). 2 refs., 4 figs., 1 tab.

Lee, J.W.; Min, J.J.; Baek, S.K.; Kang, B.H. [Samsung Advanced Institute of Technology (Korea, Republic of)

1995-07-01

226

A Three-phase to three-phase matrix converter prototype Protótipo do conversor em matriz trifásico para trifásico  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents some implementation details of a three-phase to three-phase matrix converter prototype. The bidirectional semiconductor switches were built using discrete IGBTs and fast diodes. Design aspects such as protection against overvoltage and short-circuit, commutation process of bi-directional switches, and input filter are addressed in this paper.Este trabalho apresenta aspectos relacionados a implementação experimental de um conversor trifásico em matriz. As chaves bidi...

Oliveira Filho, Milton E.; Sguarezi Filho, Alfeu J.; Ernesto Ruppert

2012-01-01

227

Reduction of Switching Losses in Active Power Filters With a New Generalized Discontinuous-PWM Strategy  

DEFF Research Database (Denmark)

The classical discontinuous pulsewidth modulations (DPWMs) cannot be efficiently applied in active power filters (APFs) because it is difficult to predict the peak values of the inverter current. Consequently, it is difficult to calculate the optimal position of the clamped interval to minimize the switching losses in any operating point. This paper proposes a new DPWM strategy for shunt APFs. The proposed modulation strategy detects the current vector position relative to the inverter voltage reference and determines the optimum clamped duration for each phase, in terms of switching power losses. It achieves a clamped voltage pattern, with variable lengths depending on the magnitude of the inverter current. This property reduces the current stress and minimizes the inverter switching losses. The proposed modulation strategy is described, analyzed, and validated on a three-phase voltage source inverter, rated at 3 kVA, 400 V, controlled as an APF. Udgivelsesdato: January

Blaabjerg, Frede; Asiminoaei, Lucian

2008-01-01

228

A New Generalized Discontinuous-PWM Strategy for Active Power Filters  

DEFF Research Database (Denmark)

Classical discontinuous pulse width modulations (DPWM's) may not be efficiently applied in active power filters, because it is hard to predict the peak values of the inverter current, and consequently it is difficult to calculate the position of the clamped interval, that minimizes the switching losses in any operating point. This paper proposes a new discontinuous pulse width modulation strategy applied to shunt active power filters. The proposed modulation strategy detects the current vector position relative to the inverter voltage reference and determines instantaneously the optimum clamped duration on each phase. It achieves a clamped voltage pattern, with variable lengths depending on the magnitude of the inverter current. This property adaptively reduces the current stress and minimizes the inverter switching losses, regardless of its application. The proposed modulation strategy is described, analyzed and validated on a three-phase voltage source inverter, rated at 7 kVA, 400 V, controlled as an active power filter.

Asiminoaei, Lucian; Rodriguez, Pedro

2007-01-01

229

Z-source inverter with a new space vector PWM algorithm for high voltage gain  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a methodology to apply a novel space vector pulse width modulation control for three phase Z-source inverter. The space vector modulation for the conventional voltage source inverter is modified so that the additional shoot-through states are inserted within the zero states. So zero voltage time period is diminished for generating a shoot-through time, and active states are unchanged. The shoot-through states are evenly distributed to each phase within zero state. The shoot-through time is used for controlling the dc link voltage boost and hence the output voltage boost of the inverter. This new method provides a high voltage gain at higher modulation index. The proposed algorithm is verified with simulation and experiment. MatLab/Simulink is used for simulating the complete circuit with RL load. The frequency spectra of the output voltage and current are explored.

U. Shajith Ali

2011-06-01

230

Research on coordinate transformation of the three-phase circuit  

Directory of Open Access Journals (Sweden)

Full Text Available The different three-phase circuit coordinate transformation matrixes are given in relevant literatures , which may cause some difficulties to understand and apply the coordinate transformation. The paper presents a general expression of the coordinate transformation matrixes in three-phase circuit and points out that the coordinate transformation matrixes having different specific expressions are due to existing the parameters which can be selected in the general expression. On this basis, the three often used expressions of coordinate transformation matrixes rotating at arbitrary speed are obtained through selecting these different parameters, which are Park transformation, orthogonal transformation and the coordinate transformation in the theory of instantaneous power. The paper further points out that, through particularly choosing coordinate rotation speed ,it can get commonly used special coordinate transformation matrixes between the three-phase stationary coordinate systems, and between the stationary coordinate system and synchronous rotating coordinate system by matrix general expression. The work of this paper shows that the three-phase circuit coordinate transformation matrixes are essentially uniformed, though their forms and practical applications are different, which is helpful to further understanding and correctly using the coordinate transformation theory of three-phase circuit.

Tian Ming Xing

2013-08-01

231

Voltage source converter HVDC connection of offshore wind farms and the application of batteries  

Energy Technology Data Exchange (ETDEWEB)

The integration of wind power into the power systems has been a theme of great interest over the last decade. Many relatively new organisations (e.g. European Wind Energy Association - EWEA; German Wind Energy Institute - DEWI) as well as longer established associations (e.g. Union for the Co-ordination of Transmission of Electricity - UCTE; International Council on Large Electric Systems - CICRE; International Electrotechnical Commission - IEC) are dealing with wind power integration. Accordingly, the number of conferences, research works and publications focusing on this topic is immense and only one part of them will be mentioned here. Several different research areas, which were important for the setting of this work, can be distinguished: (a) transmission issues with focus on the VSC HVDC, (b) wind issue - power fluctuations, forecasting etc., (c) wind power storages with focus on the battery, (d) stability issues. Being the most promising technology for the connection of large offshore wind farms with the system, VSC HVDC transmission technology is analysed in detail. Firstly, the basic principles of VSC HVDC and PWM operation are presented. The control of VSC HVDC for offshore wind power transmission is given in the subsequent section. The operation of VSC HVDC regarding control parameters and their behaviour under various conditions (reactive power control, different active power transmission, impact of the distance) then follows. At the end of this chapter the advantages and disadvantages of VSC HVDC are summarised. An overview of wind power storage possibilities is presented at the beginning of Chapter 6. Due to its excellent technical characteristics the NAS battery is discussed in detail in the next section. The possible application of ''wind farm - battery'' for power and energy applications is analysed in the subsequent part. The electrical model of the battery used for the power system simulations is introduced and explained in detail. The performances of VSC HVDC under wind power fluctuations are simulated. Similar analyses, but with the implementation within one small test power system are made. The stability of the system with and without application of the battery in a test power system is analysed. At the end of the research report the stability analysis of the entire system, including offshore wind farms, VSC HVDC connection to the PCC, battery storage and test system, is carried out and discussed. (orig.)

Spahic, Ervin

2009-07-01

232

A novel approach for pulsed high-power high-tension voltage source with inductive energy storage  

International Nuclear Information System (INIS)

This paper introduces a novel approach for the pulsed high-power high-tension voltage source with inductive energy storage developed for auxiliary heat system in fusion engineering. The technical design of a prototype for 1 MW IC RH system and the principle experiment results are given. This new type power HV modulator is rather attractive because of its simplicity of construction, ease of maintenance, high reliability, low cost, low influence for local network

1986-01-01

233

Voltage Source Converter Technology for Offshore Grids : Interconnection of Offshore Installations in a Multiterminal HVDC Grid using VSC  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This master thesis has investigated the possible application of voltage source converters (VSC) for the interconnection of offshore installations, i.e. wind farms and petroleum platforms, in a multiterminal DC (MTDC) grid. The master thesis is written at the Norwegian University of Science and Technology, Department of Electric Power Engineering and is a continuation of the project written during the autumn of 2009. The work has been carried out in cooperation with Statnett SF, the Norwegian ...

2010-01-01

234

Voltage Source Converter Technology for Offshore Grids :Interconnection of Offshore Installations in a Multiterminal HVDC Grid using VSC  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This master thesis has investigated the possible application of voltage source converters (VSC) for the interconnection of offshore installations, i.e. wind farms and petroleum platforms, in a multiterminal DC (MTDC) grid. The master thesis is written at the Norwegian University of Science and Technology, Department of Electric Power Engineering and is a continuation of the project written during the autumn of 2009. The work has been carried out in cooperation with Statnett SF, the Norwegian ...

2010-01-01

235

Evaluation of plantar fasciitis by three-phase bone scintigraphy.  

Science.gov (United States)

Fifteen patients complaining of chronic heel pain underwent three-phase Tc-99m MDP bone scintigraphy. Ten patients demonstrated abnormal scan findings consistent with plantar fasciitis (PF) and had responded to conventional therapy. Two patients were found to have calcaneal stress fractures, and one patient demonstrated a calcaneal spur that required no treatment. The remaining two patients had normal scans and did not appear clinically to have PF. The three-phase bone scan is therefore very useful in diagnosing PF and in distinguishing it from other etiologies of the painful heel syndrome. PMID:2054987

Intenzo, C M; Wapner, K L; Park, C H; Kim, S M

1991-05-01

236

A Medium-Voltage Motor Drive with a Modular Multilevel PWM Inverter Part I. Experimental Verification by a 400-V, 15-kW Downscaled Model  

Science.gov (United States)

This paper presents a medium-voltage motor drive with a three-phase modular multilevel PWM inverter and focuses on its control method and operating performance. This motor drive is particularly suitable for fans, blowers, pumps, and compressors, in which the load torque is proportional to the square of the rotating speed. Particular attention is paid to the dc-capacitor voltage fluctuation of each chopper-cell because it may affect the voltage rating of the power switching devices used. This paper describes the theoretical equations related to the amount of the voltage fluctuation. A downscaled model rated at 400V and 15kW is designed and built to confirm the validity and effectiveness of the nine-level (17-level in line-to-line) PWM inverter that is intended for use in medium-voltage motor drives to achieve energy savings.

Hagiwara, Makoto; Nishimura, Kazutoshi; Akagi, Hirofumi

237

Motor contribution during three-phase short circuit fault  

Energy Technology Data Exchange (ETDEWEB)

One of the major factors to be considered in selecting the ratings of electrical equipment (circuit breakers, bus bar bracing, etc.) is the level of three-phase short circuit current available at the equipment location in the system. The total three-phase short circuit current at a faulted point includes both the currents from the power source (such as electric utility company or in-plant generators) and contribution from electrical motors in the system. Presently, the calculation of three-phase fault current in a system is based on the method outlined in IEEE Standard 141-1976 in which the calculation of motor contribution within the system is defined. It will be pointed out that during a three-phase fault, only motors directly connected to the faulted bus or downstream buses will contribute fully to the fault. Other induction motors (with transformers connected between the motors and the fault) may or may not contribute current to the fault point. These motors will continue to receive power from the supply and act as motors. Therefore lower fault current values will be the result. This finding will have a significant bearing on borderline equipment selection with consequent savings in equipment cost. The conclusion is drawn that the calculated short circuit current based on IEEE Standard 141-1976, is higher than the actual value. This leads to unnecessarily high fuse and breaker interrupting ratings, bus bracing, etc. Computer studies and an analysis of this phenomenon are presented.

Yu, L.Y.; Bottrell, G.W.; Hamilton, D.W.; Minceff, I.

1982-11-01

238

Overhead three-phase transmission lines - Non-diagonalizable situations  

Energy Technology Data Exchange (ETDEWEB)

Physically realizable transmission lines exist to which the standard modal theory does not apply since the ZY diagonalization cannot always be undertaken successfully. In this paper the non-diagonalizing conditions for typical overhead three-phase lines are established. Algorithms are described and implemented to synthesize concrete non-diagonalizable configurations, numerical examples being presented and discussed.

Faria, J.A.B. (Centro de Electrotecnia da U.T.L. - Instituto Superior Tecnico, 1096 Lisboa (PT))

1988-10-01

239

Approaches to Suppressing Shaft Voltage in Brushless DC Motor Driven by PWM Inverter Based on Ungrounded Common-Mode Equivalent Circuit  

Science.gov (United States)

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.

Maetani, Tatsuo; Isomura, Yoshinori; Watanabe, Akihiko; Iimori, Kenichi; Morimoto, Shigeo

240

Evolutionary Computing Based Area Integration PWM Technique for Multilevel Inverters  

Directory of Open Access Journals (Sweden)

Full Text Available The existing multilevel carrier-based pulse width modulation (PWM strategies have no special provisions to offer quality output, besides lower order harmonics are introduced in the spectrum, especially at low switching frequencies. This paper proposes a novel multilevel PWM strategy to corner the advantages of low frequency switching and reduced total harmonic distortion (THD. The basic idea of the proposed area integration PWM (AIPWM method is that the area of the required sinusoidal (fundamental output and the total area of the output pulses are made equal. An attempt is made to incorporate two soft computing techniques namely evolutionary programming (EP and genetic algorithm (GA in the generation and placement of switching pulses. The results of a prototype seven-level cascaded inverter experimented with the novel PWM strategies are presented.

S. Jeevananthan

2007-06-01

 
 
 
 
241

PWM Control and Experiment of Modular Multilevel Converters  

Science.gov (United States)

A modular multilevel converter (MMC) is one of the next-generation multilevel PWM converters intended for high- or medium-voltage power conversion without transformers. The MMC consists of cascade connection of multiple bidirectional PWM chopper-cells, thus requiring voltage-balancing control of their chopper-cells. However, no paper or article has been presented or published on the voltage-balancing control with theoretical and experimental verifications. This paper deals with two types of modular multilevel PWM converters with focus on their circuit configurations and voltage-balancing control. Combination of averaging and balancing controls enables the MMCs to achieve voltage balancing without any external circuit. The viability of the MMCs as well as the effectiveness of the PWM control method is confirmed by simulation and experiment.

Hagiwara, Makoto; Akagi, Hirofumi

242

Optimized Hybrid Phase Disposition PWM Control Method for Multilevel Inverter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a new variation of hybrid phase disposition pulse width modulation technique suitable for cascaded multilevel inverter. A hybrid PDPWM is developed based on low frequency PWM and high frequency Sinusoidal PWM. An optimized sequential switching scheme introduced in this proposed method to equalize electro static and electro magnetic stress among the power devices. It is confirmed that the proposed technique offers significantly lower switching losses and switching transitio...

2010-01-01

243

Flow coupling during three-phase gravity drainage  

Science.gov (United States)

We measure the three-phase oil relative permeability kro by conducting unsteady-state drainage experiments in a 0.8 m water-wet sand pack. We find that when starting from capillary-trapped oil, kro shows a strong dependence on both the flow of water and the water saturation and a weak dependence on oil saturation, contrary to most models. The observed flow coupling between water and oil is stronger in three-phase flow than two-phase flow, and cannot be observed in steady-state measurements. The results suggest that the oil is transported through moving gas-oil-water interfaces (form drag) or momentum transport across stationary interfaces (friction drag). We present a simple model of friction drag which compares favorably to the experimental data.

Dehghanpour, H.; Aminzadeh, B.; Mirzaei, M.; Dicarlo, D. A.

2011-06-01

244

Apparatus for protection of a three-phase load  

Energy Technology Data Exchange (ETDEWEB)

The device contains a rectifier, thyristor, whose cathode is connected to the coil of an actuating relay with connection and disconnection contacts. The control electrode is connected through the resistor to the rectifier, which is connected to the source of a three-phase voltage. It has a starter with block-contact, power contacts of which are connected between the source and the load. A starter button is connected in series with the winding of the starter. In order to improve reliability, the rectifier is connected to the source of three-phase voltage between the power contacts of the starter and the load. The block-contact of the starter and the disconnecting contact of the actuating relay, whose closing contact is connected in parallel to the starter button are connected in series to the resistor in the thyristor control network.

Tarasov, Ye.I.

1981-01-01

245

Differential Protection for Arbitrary Three-Phase Power Transformers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis describes how to provide standardized, current based, differential protection for any three-phase power transformer, including phase-shifting transformers with variable phase angle shift and transformers of all construction types and internal on-load tap-changer configurations. The use of standard transformer differential protection for such applications is considered impossible in the protective relaying standards and practices currently applied. The first part of ...

Gajic?, Zoran

2008-01-01

246

A voltage-source inverter for microgrid applications with an inner current control loop and an outer voltage control loop  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Distributed generation (DG) units are commonly inter-faced to the grid by using voltage-source inverters (VSI’s). Extension of the control of these inverters allows to improve the power quality if the main power grid is disturbed or disconnected. In this paper, a control technique is developed for a VSI working in island mode. The control technique is designed in the time domain, combining an inner current control loop with an outer voltage control loop. Voltage regulation under various lin...

Vandoorn, Tine; Renders, Bert; Belie, Frederik; Meersman, Bart; Vandevelde, Lieven

2009-01-01

247

Switch-Off Behaviour of 6.5 kV IGBT Modules in Two-Level Voltage Source Inverter  

Science.gov (United States)

This paper presents an analysis of the switch-off process of 6.5 kV/200 A IGBT modules in a two-level half-bridge voltage source inverter. During experiments, it was stated that real switching process is far from ideal switch-off since parasitic inductance and capacitance in the circuit cause voltage spikes and high frequency oscillations during transition processes. Operation states of the inverter are described and analyzed. Experimental and simulation results are compared, the main transients are analyzed and mathematically expressed and possible problems and solutions are discussed.

Blinov, Andrei; Jalakas, Tanel; Vinnikov, Dmitri; Janson, Kuno

2010-01-01

248

Coping with Harmonics in Smart Grid: variable speed driveswith Back-to-Back Voltage Source Converter versus the matrix converter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this master thesis it has been investigated to utilize the matrix as a shunt active power filter and an adjustable speed drive and then compare the matrix converter with the Back-to-Back voltage source converter in terms of active filtering capability and reactive power compensation.In first steps to utilize the matrix converter as a motor drive and a shunt active power filter the control systems for the Permanent magnet synchronous machine, shunt active power filter and 3-phase LC-filter ...

2013-01-01

249

Three-Phase Harmonic Analysis Method for Unbalanced Distribution Systems  

Directory of Open Access Journals (Sweden)

Full Text Available Due to the unbalanced features of distribution systems, a three-phase harmonic analysis method is essential to accurately analyze the harmonic impact on distribution systems. Moreover, harmonic analysis is the basic tool for harmonic filter design and harmonic resonance mitigation; therefore, the computational performance should also be efficient. An accurate and efficient three-phase harmonic analysis method for unbalanced distribution systems is proposed in this paper. The variations of bus voltages, bus current injections and branch currents affected by harmonic current injections can be analyzed by two relationship matrices developed from the topological characteristics of distribution systems. Some useful formulas are then derived to solve the three-phase harmonic propagation problem. After the harmonic propagation for each harmonic order is calculated, the total harmonic distortion (THD for bus voltages can be calculated accordingly. The proposed method has better computational performance, since the time-consuming full admittance matrix inverse employed by the commonly-used harmonic analysis methods is not necessary in the solution procedure. In addition, the proposed method can provide novel viewpoints in calculating the branch currents and bus voltages under harmonic pollution which are vital for harmonic filter design. Test results demonstrate the effectiveness and efficiency of the proposed method.

Jen-Hao Teng

2014-01-01

250

Precise derating of three phase induction motors with unbalanced voltages  

International Nuclear Information System (INIS)

Performance analysis of three phase induction motors under supply voltage unbalance conditions is normally conducted using the well-known symmetrical components analysis. In this analysis, the voltage unbalance level at the terminals of the machine is assessed by means of the NEMA or IEC definitions. Both definitions lead to a relatively large error in predicting the performance of a machine. A method has recently been proposed in which, in addition to the voltage unbalance factor (VUF), the phase angle has been taken into account in the analysis. This means that the voltage unbalance factor is regarded as a complex value. This paper shows that although the use of the complex VUF reduces the computational error considerably, it is still high. This is proven by evaluating the derating factor of a three phase induction motor. A method is introduced to determine the derating factor precisely using the complex unbalance factor for an induction motor operating under any unbalanced supply condition. A practical case for derating of a typical three phase squirrel cage induction motor supplied by an unbalanced voltage is studied in the paper

2007-09-01

251

Non-traditional method-based solution for elimination of lower order harmonics in voltage source inverter feeding an induction motor drive  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 equa...

Vargese Jegathesan; Jovitha Jerome

2008-01-01

252

Three-phase Series-Connected Hybrid Converter System  

Science.gov (United States)

In this paper, a 3-phase series-connected hybrid converter system is introduced. The converter system is constructed by a GTO converter and an IGBT converter connected in series by two output transformers aiming at a high voltage high efficiency converter. The GTO converter operates in a square-wave switching mode at the same switching rate as a reference output voltage in order to minimize the device switching losses. The IGBT converter is built in an NPC (neutral-point-clamped) arrangement and operates in a PWM switching mode at a high switching rate. The former produces a base part of the total output voltage. The latter not only produces an additional part of the total output, but also offsets the harmonic components generated by the GTO converter. The control strategy for the system is proposed, and the experiment on an inverter, rectifier and STATCOM operation is demonstrated using the proposed hybrid converter. The experimental results verified the validity of the proposed hybrid configuration and its control strategy.

Li, Dongsheng; Fukuda, Shoji; Kubo, Yusuke; Kitano, Masayuki

253

A Three-phase to three-phase matrix converter prototype / Protótipo do conversor em matriz trifásico para trifásico  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Este trabalho apresenta aspectos relacionados a implementação experimental de um conversor trifásico em matriz. As chaves bidirecionais empregadas na construção do protótipo foram construídas com a utilização de componentes discretos como IGBT's e diodos rápidos. Aspectos relacionados a proteção con [...] tra sobre tensão e curto circuito, processo de comutação das chaves bidirecionais e filtro de entrada são apresentados neste trabalho juntamente com resultados experimentais da operação do conversor. Abstract in english This paper presents some implementation details of a three-phase to three-phase matrix converter prototype. The bidirectional semiconductor switches were built using discrete IGBTs and fast diodes. Design aspects such as protection against overvoltage and short-circuit, commutation process of bi-dir [...] ectional switches, and input filter are addressed in this paper.

Milton E. de, Oliveira Filho; Alfeu J., Sguarezi Filho; Ernesto, Ruppert.

254

A Novel Fuzzy—Adaptive Hysteresis Controller Based Three Phase Four Wire-Four Leg Shunt Active Filter for Harmonic and Reactive Power Compensation  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a fuzzy logic based three phase four wire four-leg shunt active power filter to suppress harmonic currents. Modified instantaneous p-q theory is adopted for calculating the compensating current. Fuzzy-adaptive hysteresis band technique is applied for the current control to derive the switching signals for the voltage source inverter. A fuzzy logic controller is developed to control the voltage of the DC capacitor. Computer simulations are carried out on a sample power system to demonstrate the suitability of the proposed control strategy, for harmonic reduction under three different conditions namely, ideal, unbalance, unbalance and distorted source voltage conditions. The proposed control strategy is found to be effective to reduce the harmonics and compensate reactive power and neutral current and balance load currents under ideal and non-ideal source voltage conditions.

P. Rathika

2011-09-01

255

Wind Farm Stabilization by using DFIG with Current Controlled Voltage Source Converters Taking Grid Codes into Consideration  

Science.gov (United States)

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.

Okedu, Kenneth Eloghene; Muyeen, S. M.; Takahashi, Rion; Tamura, Junji

256

Investigation of the behavior of a three phase grid-connected photovoltaic system to control active and reactive power  

Energy Technology Data Exchange (ETDEWEB)

In this paper, a photovoltaic (PV) system, with maximum power point tracking (MPPT), connected to a three phase grid is presented. The connection of photovoltaic system on the grid takes place in one stage using voltage source inverter (VSI). For a better utilization of the photovoltaic system, the control strategy applied is based on p-q theory. According to this strategy during sunlight the system sends active power to the grid and at the same time compensates the reactive power of the load. In case there is no sunlight (during the night for instance), the inverter only compensates the reactive power of the load. In this paper the use of p-q theory to supply the grid with active power and compensate the reactive power of the load is investigated. The advantage of this control strategy is that the photovoltaic system is operated the whole day. Furthermore, the p-q theory uses simple algebraic calculations without demanding the use of PLL to synchronize the inverter with the grid. (author)

Tsengenes, Georgios; Adamidis, Georgios [Department of Electrical Engineering and Computer Engineering, Democritus University of Thrace, University Campus Kimmeria, 67100 Xanthi (Greece)

2011-01-15

257

EMC Increasing of PWM Rectifier in Comparison with Classical Rectifier  

Directory of Open Access Journals (Sweden)

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.

R. Dolecek

2008-12-01

258

Memory formation: a new three-phase model.  

Science.gov (United States)

A new three-phase pharmacological model of memory formation is proposed: (i) a short-term memory phase lasting 10 min, inhibited by lithium chloride (LiCl) and potassium chloride (KCl), but not by ouabain; (ii) a labile, sodium pump-dependent phase occurring after 10 min, inhibited by ouabain but not by cycloheximide (CXM); and (iii) a permanent, protein synthesis-dependent phase occurring after 30 min and inhibited by CXM. Diphenylhydantoin (DPH), which stimulates Na(+)-K(+)-ATPase activity, overcomes ouabain- and CXM-induced amnesia but not LiCl- or KCl-induced amnesia. PMID:19604835

Gibbs, M E; Ng, K T

1976-05-01

259

A DSP controlled one-to-three phase matrix converter  

Energy Technology Data Exchange (ETDEWEB)

This paper deals with the theoretical analysis computer simulation and experimental results of IM fed by a one-to-three phase matrix converter which offers a unique solution for single phase electric traction applications. The proposed drive in comparison with currently used conventional drives reduces the number of power switching elements of the converter, which increases drives dependability and brings lower investment in power electronics used in drive. Further advantage is that the converter is controlled with nearly unity power factor which cuts down the operational expenses and offers higher overall performance of the drive. (orig.) 6 refs.

Dubovsky, J.; Dobrucly, B; Tabacek, R.; Havrila, R. [Department of Electric Traction and Energetics Faculty of Electrical Engineering, University of Zilina (Slovakia)

1997-12-31

260

Mathematical modeling of three-phase slurry bubble column reactors  

Energy Technology Data Exchange (ETDEWEB)

The behavior of gas-solid-liquid flow in a slurry bubble column reactor was simulated using a well-posed hydrodynamic model. The three phases under study are nitrogen, 5-{mu}m iron oxide, and SASOL wax. The phases volume fractions at various axial and radial positions in the column were computed. Preliminary results of axial solid volume fractions are consistent with experimental observations and demonstrate the potential of this method for design of such reactors. The overall objective of this study is to develop experimentally verified hydrodynamic and Fisher-Tropsch reaction models for slurry bubble column reactors.

Gamwo, I.K.; Soong, Y.; Schehl, R.R.; Zarochak, M.F. [USDOE Pittsburgh Energy Technology Center, PA (United States)

1994-12-31

 
 
 
 
261

Electric arc in three-phase metallurgical furnaces  

Science.gov (United States)

The theoretical and practical assumptions relative to the studies of electric arcs in steel-melting furnaces presented in journal Electrometallurgiya in 2011-2012 are subjected to a critical analysis. Based on classical concepts and the author experiments, the concept is presented regarding to the phases of the state and parameters of arc discharge in the ac electromagnetic field of a three-phase system. Industrial methods of eliminating the injurious effect of flash arc on furnace lining and the furnace efficiency are considered.

Vorob'ev, V. P.

2013-12-01

262

Experimental dynamic evaluation of three-phase reactors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The hydrodynamic parameters were determined for two different three-phase systems (fluidized-bed and trickle-bed) through the experimental evaluation of the dynamic residence time distribution in the gas or liquid phase. For different fluid phase flow rates the fluidized-bed system was operated with a tracer in the gas phase and in the trickle-bed with a tracer in the liquid phase. The analysis of the processes was achieved through the application of different models representing the dynamic ...

Sales, F. G.; Maranha?o, L. C. A.; Pereira, J. A. F. R.; Abreu, C. A. M.

2005-01-01

263

Three phase R.F. systems for superconducting cyclotrons  

International Nuclear Information System (INIS)

This article describes and illustrates the three phase r.f. system for superconducting cyclotrons. It is discussed that the initial design of the MSU K500 cyclotron r.f. system has since been changed and these changes are reviewed. The author describes how, after several evolutions, there is now a successful moving short for the 6 dee stems. The stem current flowing on the 4-inch O.D. inner conductor is 2600 amps RMS, resulting in a linear current density of 206 amps per inch. Problems with the operation of the r.f. system are also reviewed

1983-01-01

264

Neural network based PWM AC chopper fed induction motor drive  

Directory of Open Access Journals (Sweden)

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. .

Venkatesan Jamuna

2009-01-01

265

A Novel SVPWM Technology Used in PWM Rectifiers of WPGS  

Directory of Open Access Journals (Sweden)

Full Text Available In order to achieve the transformation of electrical energy in Variable Speed Constant Frequency (VSCF Wind Power Generation System (WPGS, a novel Space Vector Pulse Width Modulation (SVPWM pulse trigger technology applied in high efficient PWM rectifier is proposed. Rectifier is an important part of WPGS and its performance affects the harmonic content and power factor of the power energy delivered to the grid. In order to improve the performance of PWM rectifier, a novel SVPWM pulse generator technology is proposed. Compared with other kinds of PWM pulse generator systems, Space Vector Pulse Width Modulation (SVPWM has many advantages such as clear physical concept, simple algorithm, suitable for digital implementation, high voltage utilization, low harmonic content, low switches losses and simple hardware circuit.

Zhang Junli

2013-04-01

266

Realise of PWM-generating based on FPGA  

International Nuclear Information System (INIS)

The power supply digital controllers of Shanghai Synchrotron Radiation Facility(SSRF) make use of the PWM (pulse width modulation) wave as the feedback to the power-electrical devices, so as to obtain constant current of high accuracy and stability. The design of PWM wave generation structure in FPGA is good for a compact controller,and the reduction of the usage of Integrated Circuits (ICs) decreases the interference from the noise among the ICs, hence better performance of the controller. In addition, FPGA can be programmed circularly at any time,so as to optimize the structure design and make a maximum use of the advantage of FPGA. As a part of transplanting the complete function of the DSP (digital signal processor/processing), realizing the generation of PWM wave in FPGA is feasible. In this paper, we report progress in this regard at SSRF. (authors)

2012-06-01

267

A fuzzy controlled three-phase centrifuge for waste separation  

Energy Technology Data Exchange (ETDEWEB)

The three-phase centrifuge technology discussed in this paper was developed by Neal Miller, president of Centech, Inc. The three-phase centrifuge is an excellent device for cleaning up oil field and refinery wastes which are typically composed of hydrocarbons, water, and solids. The technology is unique. It turns the waste into salable oil, reusable water, and landfill-able solids. No secondary waste is produced. The problem is that only the inventor can set up and run the equipment well enough to provide an optimal cleanup. Demand for this device has far exceeded a one man operation. There is now a need for several centrifuges to be operated at different locations at the same time. This has produced a demand for an intelligent control system, one that could replace a highly skilled operator, or at least supplement the skills of a less experienced operator. The control problem is ideally suited to fuzzy logic, since the centrifuge is a highly complicated machine operated entirely by the skill and experience of the operator. A fuzzy control system was designed for and used with the centrifuge.

Parkinson, W.J.; Smith, R.E. [Los Alamos National Lab., NM (United States); Miller, N. [Centech, Inc., Casper, WY (United States)

1998-02-01

268

Generalized inflow performance relationships for three-phase flow  

Energy Technology Data Exchange (ETDEWEB)

Inflow performance relationships (IPRs) are empirical relationships based on linear regression analysis of simulator results that cover a wide range of reservoir fluid and rock properties. The IPRs developed are compared with other three-phase methods and yield similar results for production-pressure behavior during boundary-dominated flow while being much simpler to use. The proposed IPRs were developed from analysis of multiphase flow in bounded, homogeneous reservoirs without external influx of fluids into the reservoir and apply to the boundary-dominated flow regime. The relationships are limited by the assumptions that (1) the reservoirs are initially at the bubblepoint, (2) no initial free gas phase is present, (3) a mobile water phase is present for three-phase studies, (4) Darcy's law for multiphase flow applies, (5) isothermal conditions exist, (6) no reactions take place between reservoir fluids and reservoir rock, (7) no gas solubility exists in the water, (8) gravity effects are negligible, and (9) the wellbore is fully penetrating.

Wiggins, M.L. (Univ. of Oklahoma, Norman, OK (United States))

1994-08-01

269

Three-phase bone scintigraphy of Kienboeck disease  

International Nuclear Information System (INIS)

Thirty-three joints in 31 patients with Kienboeck disease were evaluated with three-phase bone scintigraphy. Follow-up studies were performed in 19 cases of them. The patients with increased ulnar blood flow on arterial phase and ample perfusion on venous phase in angiograms showed good clinical prognosis. This ample ulnar blood flow and perfusion might be essential for the recovery of this disease. Although staging was possible using static images alone, blood pool images provided more information about the present condition of lesions, such as hyperemic state and remodeling reactions. Blood pool image was indispensable for staging and analyzing lesions and evaluating post-operative course. Increased lunate perfusion in venous phase of angiograms and localized lunate uptake in blood pool images were the favorable signs, which were shown in most cases with good prognosis. It is concluded that three-phase bone scintigraphy gives useful information for evaluating Kienboeck disease which can not be obtained by conventional bone scintigraphy. (author)

1992-12-01

270

Experimental dynamic evaluation of three-phase reactors  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The hydrodynamic parameters were determined for two different three-phase systems (fluidized-bed and trickle-bed) through the experimental evaluation of the dynamic residence time distribution in the gas or liquid phase. For different fluid phase flow rates the fluidized-bed system was operated with [...] a tracer in the gas phase and in the trickle-bed with a tracer in the liquid phase. The analysis of the processes was achieved through the application of different models representing the dynamic behavior of tracers present in the gas and liquid phases with a simulation of experimental operations of the three-phase reactors. The transfer functions developed for the two systems made it possible to estimate the hydrodynamic parameters providing the gas holdup (2.22 x 10-2 to 8.42 x 10-2) and the gas phase Peclet number (54.18 to 41.20) for the fluidized-bed and the liquid holdup (0.16 to 0.25), the liquid phase Peclet number (20.37 to 4.52) and wetting efficiency (0.34 to 0.56) for the trickle-bed.

Sales, F. G.; Maranhão, L. C. A.; Pereira, J. A. F. R.; Abreu, C. A. M..

271

Experimental dynamic evaluation of three-phase reactors  

Directory of Open Access Journals (Sweden)

Full Text Available The hydrodynamic parameters were determined for two different three-phase systems (fluidized-bed and trickle-bed through the experimental evaluation of the dynamic residence time distribution in the gas or liquid phase. For different fluid phase flow rates the fluidized-bed system was operated with a tracer in the gas phase and in the trickle-bed with a tracer in the liquid phase. The analysis of the processes was achieved through the application of different models representing the dynamic behavior of tracers present in the gas and liquid phases with a simulation of experimental operations of the three-phase reactors. The transfer functions developed for the two systems made it possible to estimate the hydrodynamic parameters providing the gas holdup (2.22 x 10-2 to 8.42 x 10-2 and the gas phase Peclet number (54.18 to 41.20 for the fluidized-bed and the liquid holdup (0.16 to 0.25, the liquid phase Peclet number (20.37 to 4.52 and wetting efficiency (0.34 to 0.56 for the trickle-bed.

F. G. Sales

2005-09-01

272

An NPC/H-bridge modular photovoltaic grid connected inverter with new-phase shifted PWM technique  

Energy Technology Data Exchange (ETDEWEB)

The commonly used topologies for converting direct current power generated by solar panels to high quality alternating current power at the interface to the grid are the high- frequency and line frequency voltage source grid interface system. These topologies utilize transformers which come with negative features such as increase in cost, size and weight of the whole inverter. In addition, the efficiency and reliability of the system is reduced. A novel option for inverters is the multilevel concept as it is based on low frequency switching and provides voltage or current of low sharing between the power semiconductors. The key topologies which have been suggested for multilevel converters are diode clamped or neutral point clamped (NPC); capacitor clamped of flying capacitors (FC); and cascaded H-bridge inverters with separate direct current sources. The cascaded H-bridge converter demonstrates superior qualities among the multilevel converter topologies as a result of its modularity and flexibility. This paper investigated the operating principle of a cascaded NPC/H-bridge inverter for photovoltaic-grid application. The superior characteristics of the model were analyzed using the state space techniques and double Fourier principle. A new and improved phase sifted PWM technique was proposed and its performance was compared. The main system configuration, mathematical modeling, and simulation model were presented. The state space equation showed that the model has 8 different operating modes which can be utilized to realize 5 level voltages per cell. 13 refs., 1 tab., 6 figs.

Wanjekeche, T.; Nicolae, D.V.; Jimoh, A.A. [Tshwane Univ. of Technology, Pretoria (South Africa). Dept. of Electrical Engineering

2010-08-13

273

Voltage Sag Mitigation by PWM Autotransformer Technique  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of this research is to develop a novel voltage control scheme that can compensate for voltagesag and swell conditions in three-phase power systems. Faults occurring in power distribution systems or facilities inplants cause the voltage sag or swell. If a fault occurs, it can damage the power system or user's facility. Sensitivity tovoltage sags and swells varies within different applications. For sensitive loads, even voltage sags of short durationcan cause serious problems in the entire system. Normally, a voltage interruption triggers a protection device, whichcauses shutdown of the entire system.

ASHOK L. VAGHAMSHI

2012-06-01

274

Design of current controller of grid-connected voltage source converter based internal model control in wind power  

Energy Technology Data Exchange (ETDEWEB)

Grid-connected voltage source converter (VSC) is important for variable speed turbines with doubly fed induction generator (DFIG), and bad performance of current loop of VSC may cause VSC inject much low and high order harmonics into grid. Therefore, design of current controller of VSC is very important. PI regulator is often used to regulate current error in dq rotating coordinate to obtain zero steady error. However, it is complex to design PI parameters, and researchers need many trial-and-error steps. Therefore, a novel and simple design method of PI regulator for grid-connected VSC, which is based internal model control (IMC), has been presented in this paper. The parameters of PI regulator can be expressed directly with certain L-type line filter parameters and the desired closed-loop bandwidth. At last, The simulation has been done and result shows that the method in this paper is easy and useful to regulate PI parameters. (orig.)

Zhang Xianping; Guo Jindong; Xu Honghua [Inst. of Electrical Engineering, Chinese Academy of Sciences, BJ (China)

2008-07-01

275

ADVANCED COMPUTATIONAL MODEL FOR THREE-PHASE SLURRY REACTORS  

Energy Technology Data Exchange (ETDEWEB)

In the first year of the project, solid-fluid mixture flows in ducts and passages at different angle of orientations were analyzed. The model predictions are compared with the experimental data and good agreement was found. Progress was also made in analyzing the gravity chute flows of solid-liquid mixtures. An Eulerian-Lagrangian formulation for analyzing three-phase slurry flows in a bubble column is being developed. The approach uses an Eulerian analysis of gas liquid flows in the bubble column, and makes use of the Lagrangian particle tracking procedure to analyze the particle motions. Progress was also made in developing a rate dependent thermodynamically consistent model for multiphase slurry flows in a state of turbulent motion. The new model includes the effect of phasic interactions and leads to anisotropic effective phasic stress tensors. Progress was also made in measuring concentration and velocity of particles of different sizes near a wall in a duct flow. The formulation of a thermodynamically consistent model for chemically active multiphase solid-fluid flows in a turbulent state of motion was also initiated. The general objective of this project is to provide the needed fundamental understanding of three-phase slurry reactors in Fischer-Tropsch (F-T) liquid fuel synthesis. The other main goal is to develop a computational capability for predicting the transport and processing of three-phase coal slurries. The specific objectives are: (1) To develop a thermodynamically consistent rate-dependent anisotropic model for multiphase slurry flows with and without chemical reaction for application to coal liquefaction. Also to establish the material parameters of the model. (2) To provide experimental data for phasic fluctuation and mean velocities, as well as the solid volume fraction in the shear flow devices. (3) To develop an accurate computational capability incorporating the new rate-dependent and anisotropic model for analyzing reacting and nonreacting slurry flows, and to solve a number of technologically important problems related to Fischer-Tropsch (F-T) liquid fuel production processes. (4) To verify the validity of the developed model by comparing the predicted results with the performed and the available experimental data under idealized conditions.

Goodarz Ahmadi

2000-11-01

276

Advanced computational model for three-phase slurry reactors  

International Nuclear Information System (INIS)

In the first year of the project, solid-fluid mixture flows in ducts and passages at different angle of orientations were analyzed. The model predictions are compared with the experimental data and good agreement was found. Progress was also made in analyzing the gravity chute flows of solid-liquid mixtures. An Eulerian-Lagrangian formulation for analyzing three-phase slurry flows in a bubble column is being developed. The approach uses an Eulerian analysis of gas liquid flows in the bubble column, and makes use of the Lagrangian particle tracking procedure to analyze the particle motions. Progress was also made in developing a rate dependent thermodynamically consistent model for multiphase slurry flows in a state of turbulent motion. The new model includes the effect of phasic interactions and leads to anisotropic effective phasic stress tensors. Progress was also made in measuring concentration and velocity of particles of different sizes near a wall in a duct flow. The formulation of a thermodynamically consistent model for chemically active multiphase solid-fluid flows in a turbulent state of motion was also initiated. The general objective of this project is to provide the needed fundamental understanding of three-phase slurry reactors in Fischer-Tropsch (F-T) liquid fuel synthesis. The other main goal is to develop a computational capability for predicting the transport and processing of three-phase coal slurries. The specific objectives are: (1) To develop a thermodynamically consistent rate-dependent anisotropic model for multiphase slurry flows with and without chemical reaction for application to coal liquefaction. Also to establish the material parameters of the model. (2) To provide experimental data for phasic fluctuation and mean velocities, as well as the solid volume fraction in the shear flow devices. (3) To develop an accurate computational capability incorporating the new rate-dependent and anisotropic model for analyzing reacting and nonreacting slurry flows, and to solve a number of technologically important problems related to Fischer-Tropsch (F-T) liquid fuel production processes. (4) To verify the validity of the developed model by comparing the predicted results with the performed and the available experimental data under idealized conditions

2000-01-01

277

ADVANCED COMPUTATIONAL MODEL FOR THREE-PHASE SLURRY REACTORS  

Energy Technology Data Exchange (ETDEWEB)

In the second year of the project, the Eulerian-Lagrangian formulation for analyzing three-phase slurry flows in a bubble column is further developed. The approach uses an Eulerian analysis of liquid flows in the bubble column, and makes use of the Lagrangian trajectory analysis for the bubbles and particle motions. An experimental set for studying a two-dimensional bubble column is also developed. The operation of the bubble column is being tested and diagnostic methodology for quantitative measurements is being developed. An Eulerian computational model for the flow condition in the two-dimensional bubble column is also being developed. The liquid and bubble motions are being analyzed and the results are being compared with the experimental setup. Solid-fluid mixture flows in ducts and passages at different angle of orientations were analyzed. The model predictions were compared with the experimental data and good agreement was found. Gravity chute flows of solid-liquid mixtures is also being studied. Further progress was also made in developing a thermodynamically consistent model for multiphase slurry flows with and without chemical reaction in a state of turbulent motion. The balance laws are obtained and the constitutive laws are being developed. Progress was also made in measuring concentration and velocity of particles of different sizes near a wall in a duct flow. The technique of Phase-Doppler anemometry was used in these studies. The general objective of this project is to provide the needed fundamental understanding of three-phase slurry reactors in Fischer-Tropsch (F-T) liquid fuel synthesis. The other main goal is to develop a computational capability for predicting the transport and processing of three-phase coal slurries. The specific objectives are: (1) To develop a thermodynamically consistent rate-dependent anisotropic model for multiphase slurry flows with and without chemical reaction for application to coal liquefaction. Also establish the material parameters of the model. (2) To provide experimental data for phasic fluctuation and mean velocities, as well as the solid volume fraction in the shear flow devices. (3) To develop an accurate computational capability incorporating the new rate-dependent and anisotropic model for analyzing reacting and nonreacting slurry flows, and to solve a number of technologically important problems related to Fischer-Tropsch (F-T) liquid fuel production processes. (4) To verify the validity of the developed model by comparing the predicted results with the performed and the available experimental data under idealized conditions.

Goodarz Ahmadi

2001-10-01

278

Advanced computational model for three-phase slurry reactors  

International Nuclear Information System (INIS)

In the second year of the project, the Eulerian-Lagrangian formulation for analyzing three-phase slurry flows in a bubble column is further developed. The approach uses an Eulerian analysis of liquid flows in the bubble column, and makes use of the Lagrangian trajectory analysis for the bubbles and particle motions. An experimental set for studying a two-dimensional bubble column is also developed. The operation of the bubble column is being tested and diagnostic methodology for quantitative measurements is being developed. An Eulerian computational model for the flow condition in the two-dimensional bubble column is also being developed. The liquid and bubble motions are being analyzed and the results are being compared with the experimental setup. Solid-fluid mixture flows in ducts and passages at different angle of orientations were analyzed. The model predictions were compared with the experimental data and good agreement was found. Gravity chute flows of solid-liquid mixtures is also being studied. Further progress was also made in developing a thermodynamically consistent model for multiphase slurry flows with and without chemical reaction in a state of turbulent motion. The balance laws are obtained and the constitutive laws are being developed. Progress was also made in measuring concentration and velocity of particles of different sizes near a wall in a duct flow. The technique of Phase-Doppler anemometry was used in these studies. The general objective of this project is to provide the needed fundamental understanding of three-phase slurry reactors in Fischer-Tropsch (F-T) liquid fuel synthesis. The other main goal is to develop a computational capability for predicting the transport and processing of three-phase coal slurries. The specific objectives are: (1) To develop a thermodynamically consistent rate-dependent anisotropic model for multiphase slurry flows with and without chemical reaction for application to coal liquefaction. Also establish the material parameters of the model. (2) To provide experimental data for phasic fluctuation and mean velocities, as well as the solid volume fraction in the shear flow devices. (3) To develop an accurate computational capability incorporating the new rate-dependent and anisotropic model for analyzing reacting and nonreacting slurry flows, and to solve a number of technologically important problems related to Fischer-Tropsch (F-T) liquid fuel production processes. (4) To verify the validity of the developed model by comparing the predicted results with the performed and the available experimental data under idealized conditions

2001-01-01

279

Evaluation of Three-Phase Transformerless Photovoltaic Inverter Topologies  

DEFF Research Database (Denmark)

This paper analyzes and compares three transformerless photovoltaic inverter topologies for three-phase grid connection with the main focus on the safety issues that result from the lack of galvanic isolation. A common-mode model, valid at frequencies lower than 50 kHz, is adopted to study the leakage current paths. The model is validated by both simulation and experimental results. These will be used to compare the selected topologies, and to explain the influence of system unbalance and the neutral conductor inductance on the leakage current. It will be demonstrated that the later has a crucial influence. Finally, a comparison of the selected topologies is carried out, based on the adopted modulation, connection of the neutral and its inductance, effects of unbalance conditions, component ratings, output voltage levels, and filter size. Udgivelsesdato: September

Kerekes, Tamas; Liserre, Marco

2009-01-01

280

Transient three-phase three-component flow. Pt. 3  

International Nuclear Information System (INIS)

A mathematical model of a transient three-dimensional three-phase three-component flow described by three-velocity fields in porous body is presented. A combination of separated mass and energy equations together with mixture momentum equations for the flow is used. The mixture equations are used in diffusion form with the assumption that the diffusion velocity can be calculated from empirical correlations. An analytical coupling between the governing equations is developed for calculation of the pressure field. The system is discretized semiimplicitly in 3D-cylindrical space and different solution methods for the algebraic problem are presented. Finally, numerical examples and comparisons with experimental data demonstrate that the method presented is a powerful tool for numerical multiphase flow simulation. (orig.)

1986-01-01

 
 
 
 
281

Myositis ossificans and the three-phase bone scan  

International Nuclear Information System (INIS)

Myositis ossificans circumscripta (or paraosteoarthropathy) in paraplegics has been a well known entity since its classic description in 1918 by Dejerine and Ceillier. The disease is characterized by ectopic bone formation, primarily occurring in the particular soft tissues of the hips and knees. Hypotheses concerning its origin have been proposed, but its etiology is still unknown. Myositis ossificans can occur after traumatic injury, but develops in paraplegics without apparent injury in the involved regions. Radionuclide techniques have been used in the evaluation of myositis ossificans, particularly with serial studies to stage the activity of the disease. The author reports a case of myositis ossificans in a paraplegic that emphasizes the benefit of the three-phase bone scan in the early diagnosis of this disorder

1984-01-01

282

Myositis ossificans and the three-phase bone scan  

Energy Technology Data Exchange (ETDEWEB)

Myositis ossificans circumscripta (or paraosteoarthropathy) in paraplegics has been a well known entity since its classic description in 1918 by Dejerine and Ceillier. The disease is characterized by ectopic bone formation, primarily occurring in the particular soft tissues of the hips and knees. Hypotheses concerning its origin have been proposed, but its etiology is still unknown. Myositis ossificans can occur after traumatic injury, but develops in paraplegics without apparent injury in the involved regions. Radionuclide techniques have been used in the evaluation of myositis ossificans, particularly with serial studies to stage the activity of the disease. The author reports a case of myositis ossificans in a paraplegic that emphasizes the benefit of the three-phase bone scan in the early diagnosis of this disorder.

Drane, W.E.

1984-01-01

283

Mass transfer in three-phase fluidized beds  

International Nuclear Information System (INIS)

The effects of superficial liquid and gas velocity, particle diameter, liquid viscosity, and column diameter on liquid dispersion (E/sub L) and mass transfer (K/sub L/a) in three-phase fluidized beds were investigated using a water--glycerol/oxygen--nitrogen (or oxygen--argon)/glass-bead system. Overall mass transfer coefficients were calculated based on plug flow, dispersed plug flow, and continuously stirred tank models. k/sub L/a was found to increase with gas velocity and particle diameter, but no correlation of K/sub L/a with liquid velocity was observed. At low liquid velocities, K/sub L/a was lower for the more viscous liquid; the reverse was true at high liquid flow rates. E/sub L/ increased rapidly for liquid flow rates at two to three times the minimum fluidization velocity

1978-01-01

284

Three Phase High Power Quality Two- Stage Boost Rectifier  

Directory of Open Access Journals (Sweden)

Full Text Available Three-phase two-stage boost rectifier with sinusoidal input current are presented and a novel topology with two active power devices is proposed. These contain a capacitor for pumping action in DC circuit. This gives twostage boost operation to obtain higher DC output voltage. The rectifier can be operated in the switch mode forpumping action and for forcing the input current to follow its sinusoidal reference independent of the working conditions. The results of the proposed rectifier are compared with those of the rectifier with a single active power device. The simulation result gives the better output DC voltage regulation under open loop condition. The simulated results prove that the proposed rectifier has the expected performance.

P.NAMMALVAR

2012-04-01

285

Three Phase Bone Scintigraphy in Active and Inactive Osteomyelitis  

International Nuclear Information System (INIS)

To Appreciate the value of bone scintigraphy in determination of the bony infection, we performed three phase bone scintigraphy in 34 cases of osteomyelitis of extremities prospectively. They were clinically inactive in 11 and active in 23 cases. We confirmed the active osteomyelitis by operation or aspiration within one week after scintigraphy. Perfusion, blood pool and delayed images were analyzed respectively and compared with the plain roentgenograms. All 23 active lesions showed diffusely increased perfusion in affected limbs. The areas of the increased activities on blood pool images were larger than or similar to those on delayed images in 17 cases (73.9%) with active osteomyelitis and smaller in 6 cases (26.1%). 5 of the latter 6 cases showed definite soft tissue activities on blood pool images. In inactive cases bone scintigrams were completely normal in 4 cases. Two of those were normal on plain films and remaining two showed mild focal bony sclerosis. Among 7 inactive lesions, perfusion was normal in 2 cases, diffusely increased in 4 cases and diffusely decreased in 1 case. 6 of these 7 cases showed increased activities both on blood pool and delayed images and the areas of increased activities on blood pool images didn't exceed those on delayed images. Bony sclerosis was noted on plain films in those 7 inactive lesions and the extent of the sclerosis correlated well to delayed images. Large blood pool activity was characteristics of active osteomyelitis. Normal three phase bone scintigram may indicate the time to terminate the treatment, but increased activity on perfusion and blood pool scans is not absolute indication of active lesion if the extent of the lesion on the blood pool image is smaller than that on delayed image and if no definite soft tissue activity is noted on perfusion and blood pool images in clinically inactive patient.

1988-07-01

286

Non-traditional method-based solution for elimination of lower order harmonics in voltage source inverter feeding an induction motor drive  

Directory of Open Access Journals (Sweden)

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.

Vargese Jegathesan

2008-01-01

287

Carrier Based Pulse Width Modulation Control of a Non-Square Direct Matrix Converter with Seven-phase Input and Three-phase Output  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents pulse width modulation technique for a direct ac-ac converter. The converter has seven-phase input supply and three-phase output. The input supply may be obtained from a seven-phase wind energy generation system with variable output voltage magnitude and frequency. The output of the proposed converter topology may be fed to the three-phase stiff grid system. Thus the requirement of the modulation of the ac-ac converter is to produce fixed voltage and fixed frequency output while the input can be variable. Additionally the output voltage gain should be high. Simple carrier-based PWM technique is suggested and harmonic injection scheme is proposed to enhance the output voltage magnitude. The output voltage reaches 90% of the input supply voltage with the proposed technique. An additional control block is used to stabilize the output voltage and frequency of the converter. Simulation results are shown in the paper for the verification of the proposed scheme.

Sk Moin Ahmed

2013-07-01

288

A new Zero-Voltage-Transition PWM switching cell  

Energy Technology Data Exchange (ETDEWEB)

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.

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

289

A new Zero-Current-Transition PWM switching cell  

Energy Technology Data Exchange (ETDEWEB)

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.

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

290

Simulation of Single-Phase Cascade Multilevel PWM Inverters  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents simulation of a single –phase cascade multilevel PWM inverter topology.Solution is based on series connection of 3 level diodeclamped inverters modules and flying capacitor invertermodules, which gives possibility for flexible operation ofinverter at various high voltage.

Felicia ?chiop

2008-05-01

291

Boosted PWM open loop control of hydraulic proportional valves  

International Nuclear Information System (INIS)

This paper presents an innovative open loop control technique for direct single stage hydraulic proportional valves whose response rate is significantly higher than that obtained by standard open loop control techniques, even comparable to more costly commercial closed loop systems. Different from standard open loop techniques, which provide the coil with a constant current proportional to the target position, the control strategy proposed in this paper employs the peak and hold (P and H) technique, widely used in Diesel engine modern supply systems, to boost the duty cycle value of the pulse width modulation (PWM) signal for a short time, namely during the spool displacement, while maintaining a lower duty cycle for holding the spool in the required opening position. The developed 'boosted PWM' technique only requires a low cost microcontroller, such as a peripheral interface controller (PIC) equipped with a metal oxide semiconductor (MOS) power driver. The PWM parameters are calibrated as a function of the spool displacement so as to maximize the response rate without introducing overshoots: the collected data are stored in the PIC. Different valve opening procedures with step response have been compared to demonstrate the merits of the proposed boosted PWM technique. No overshoots have been registered. Moreover, the proposed method is characterized by a significantly higher response rate with respect to a standard open loop control, which approximately has the same cost. Similar experimental tests show that the proposed boosted PWM technique has a response rate even higher than that provided by the more costly commercial closed loop system mounted on the valve, and it produces no overshoots

2008-08-01

292

Inverter Output Filter Effect on PWM Motor Drives of a Flywheel Energy Storage System  

Science.gov (United States)

NASA Glenn Research Center (GRC) has been involved in the research and development of high speed flywheel systems for small satellite energy storage and attitude control applications. One research and development area has been the minimization of the switching noise produced by the pulsed width modulated (PWM) inverter that drives the flywheel permanent magnet motor/generator (PM M/G). This noise can interfere with the flywheel M/G hardware and the system avionics hampering the full speed performance of the flywheel system. One way to attenuate the inverter switching noise is by placing an AC filter at the three phase output terminals of the inverter with the filter neutral point connected to the DC link (DC bus) midpoint capacitors. The main benefit of using an AC filter in this fashion is the significant reduction of the inverter s high dv/dt switching and its harmonics components. Additionally, common mode (CM) and differential mode (DM) voltages caused by the inverter s high dv/dt switching are also reduced. Several topologies of AC filters have been implemented and compared. One AC filter topology consists of a two-stage R-L-C low pass filter. The other topology consists of the same two-stage R-L-C low pass filter with a series connected trap filter (an inductor and capacitor connected in parallel). This paper presents the analysis, design and experimental results of these AC filter topologies and the comparison between the no filter case and conventional AC filter.

Santiago, Walter

2004-01-01

293

Speed and position sensorless control of permanent magnet synchronous motor in matrix converter and voltage source converter applications  

Energy Technology Data Exchange (ETDEWEB)

In this thesis the sensorless control of a permanent magnet synchronous motor (PMSM) is studied. The study has two main purposes. The first is to find a simple and effective method to estimate the rotor position and angular speed of the PMSM. The second is to test the applicability of a matrix converter in sensorless PMSM drives. A matrix converter (MC) enables a direct frequency conversion without DC-link with energy storage. In this thesis two matrix converter topologies, direct and indirect, are studied. The vector modulation and the current commutation strategies of a matrix converter are described. Non-ideal properties of frequency converters such as dead times, overlapping times and voltage losses over semiconductors are disturbances for a control system and position estimator. These non-idealities are studied and the properties of a conventional voltage source inverter are compared to direct and indirect MC topologies. The rotor position and angular speed of the PMSM can be estimated by various methods. Estimators can be divided into model based estimators and signal injection estimators. Model based estimators calculate mechanical quantities using the mathematical representation of the motor. Injection methods usually exploit the saliency of the PMSM. Injected voltage creates currents which are modulated by the rotor position. The position information can be extracted from measured currents. In this thesis the best features of model based and injection estimators are combined. In the proposed hybrid method signal injection is used at low speeds and the transition to model based estimator is performed when the speed increases. The estimator methods used in the hybrid estimator are selected by a comparative analysis and simulations. The most important criteria in the selection of the estimator method in this thesis are: simple algorithm and no need for modification of the modulator software or frequency converter. The suitability of the proposed hybrid estimator is tested by simulations and experimental tests in various operating conditions. To test the performance of the matrix converter the experiments are carried out using both MC topologies and a conventional voltage source converter. The results obtained show that a matrix converter can be used in PMSM drives where the speed and position of the PMSM are not measured. The proposed estimator method is stable over the nominal speed range including the zero speed region with full load torque. (orig.)

Eskola, M.

2006-07-01

294

Improvement of the efficiency of three-phase motors  

Energy Technology Data Exchange (ETDEWEB)

The feasibility of optimizing the efficiency and of energy saving on asynchronous three-phase motors both with squirrel-cage or slip-ring rotor in the output range of approx. 100 to 1500 kW has been investigated with respect to three topics, i.e. optimizing of mains-supplied asynchronous machines, optimizing of inverter-supplied asynchronous machines, and the use of electronic components for speed variation. The origins of losses have been checked theoretically as well as in numerous serial tests. Special attention has been paid to the relations of the various losses to the structur's, material's and technology's parameters. The most considerable loss savings are achieved by a machine optimized regarding its electro-magnetic design and the insulation technique. The operational behaviour as well as the strains even during critical dynamic phases has therefore to be taken into account. On inverter supplied machines considerable energy savings can be achieved compared to standard motors by additional measurements. Under certain circumstances even the use of a thyristor-based voltage control can result in remarkable energy savings. The biggest potential for possible energy savings is in the field of elevator technique in the speed range up to approx. 2 m/sec., and in the hoisting technique. In the long run the best saving results can be expected by using inverters, especially in the field of centrifuges, pumps and ventilators.

Falk, K.; Schoerner, J.

1982-01-01

295

ISOBUTANOL FROM SYNGAS IN A THREE PHASE SYSTEM  

Energy Technology Data Exchange (ETDEWEB)

With growing interest in oxygenates as octane booster for automotive fuels, various synthesis routes for these chemicals are being investigated. Among others, alternative routes to isobutene, the C4-components in MTBE-synthesis are under investigation. A promising path to isobutene is the heterogeneously catalyzed CO-hydrogenation to isobutanol with following dehydration (Fig. 1). As shown by thermodynamical studies, the heterogeneously catalyzed CO-hydrogenation to isobutanol is not expected to experience any thermodynamic constraints. However, heterogeneous hydrogenation of CO is a very exothermic process, a problem which can only be partly solved when being conducted in a plug flow reactor. When carried out in reaction vessels with moving catalyst bed (e.g. three phase stirred tank), heat transfer problems can be resolved, along with additional benefits connected with this reactor type. Several heterogeneous catalytic systems have been under investigation for their capability of isobutanol synthesis from syngas. Most promising catalysts for an active and selective isobutanol synthesis from CO are modified high temperature methanol catalysts.

Peter Tijrn

2002-12-29

296

Mathematical modeling of a three-phase trickle bed reactor  

Directory of Open Access Journals (Sweden)

Full Text Available The transient behavior in a three-phase trickle bed reactor system (N2/H2O-KCl/activated carbon, 298 K, 1.01 bar was evaluated using a dynamic tracer method. The system operated with liquid and gas phases flowing downward with constant gas flow Q G = 2.50 x 10-6 m³ s-1 and the liquid phase flow (Q L varying in the range from 4.25x10-6 m³ s-1 to 0.50x10-6 m³ s-1. The evolution of the KCl concentration in the aqueous liquid phase was measured at the outlet of the reactor in response to the concentration increase at reactor inlet. A mathematical model was formulated and the solutions of the equations fitted to the measured tracer concentrations. The order of magnitude of the axial dispersion, liquid-solid mass transfer and partial wetting efficiency coefficients were estimated based on a numerical optimization procedure where the initial values of these coefficients, obtained by empirical correlations, were modified by comparing experimental and calculated tracer concentrations. The final optimized values of the coefficients were calculated by the minimization of a quadratic objective function. Three correlations were proposed to estimate the parameters values under the conditions employed. By comparing experimental and predicted tracer concentration step evolutions under different operating conditions the model was validated.

J. D. Silva

2012-09-01

297

Mathematical modeling of a three-phase trickle bed reactor  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The transient behavior in a three-phase trickle bed reactor system (N2/H2O-KCl/activated carbon, 298 K, 1.01 bar) was evaluated using a dynamic tracer method. The system operated with liquid and gas phases flowing downward with constant gas flow Q G = 2.50 x 10-6 m³ s-1 and the liquid phase flow (Q [...] L) varying in the range from 4.25x10-6 m³ s-1 to 0.50x10-6 m³ s-1. The evolution of the KCl concentration in the aqueous liquid phase was measured at the outlet of the reactor in response to the concentration increase at reactor inlet. A mathematical model was formulated and the solutions of the equations fitted to the measured tracer concentrations. The order of magnitude of the axial dispersion, liquid-solid mass transfer and partial wetting efficiency coefficients were estimated based on a numerical optimization procedure where the initial values of these coefficients, obtained by empirical correlations, were modified by comparing experimental and calculated tracer concentrations. The final optimized values of the coefficients were calculated by the minimization of a quadratic objective function. Three correlations were proposed to estimate the parameters values under the conditions employed. By comparing experimental and predicted tracer concentration step evolutions under different operating conditions the model was validated.

J. D., Silva; C. A. M., Abreu.

298

Description of the three-phase contact line expansion  

Directory of Open Access Journals (Sweden)

Full Text Available Knowledge of bubble-particle interaction is important in many industrial processes such as in flotation. While the collision (first interaction sub-process between bubbles and particles is influenced only by hydrodynamic forces, the bubble behaviour during the attachment (second sub-process is influenced both by hydrodynamic and surface forces. This work is focused on the study of the three-phase contact (TPC line expansion during bubble adhesion on hydrophobic surface and on its experimental and mathematical description. The experiments were carried out in pure water where mobile bubble surface is expected. The rising bubble was studied in dynamic arrangement, whereas the stationary bubble was analysed in static arrangement. The attachment process was recorded using a high-speed digital camera and evaluated using image analysis. The diameter of the expanding TPC line as well as the dynamic contact angle was determined. Two approaches - the hydrodynamic and the molecular-kinetic - were used for mathematical description of the TPC line expansion. According to our results, the hydrodynamic model is suitable for the description of the initial fast phase of the expansion. The molecular-kinetic model was assessed as appropriate for almost whole range of TPC expansion. Parameters of the model were evaluated and compared for both types of arrangement.

Váchová Tereza

2014-03-01

299

Three-phase inverter for small high speed motors  

Science.gov (United States)

A high-frequency three-phase inverter is being developed to drive a miniature centrifugal compressor which is a key component in a long-life space-borne cryocooler. The inverter is a unique transformer-coupled design, tailored to the low-voltage high-current characteristic of the compressor's induction motor. The design and performance demonstration of a breadboard model of the inverter are described. The cryocooler uses a reverse-Brayton cycle with turbomachines to provide 5 watt of cooling at 70 K. The design target for input power to the compressor motor is 175 watts. Line-to-neutral phase voltage waveforms to be supplied by the inverter have an amplitude of 15 volt-rms at a frequency of 8 kHz. DC power at 28 volt is supplied to the inverter. The breadboard inverter was tested with a preliminary development model of the compressor. It drove the compressor over a range of operating conditions encompassing frequencies of 5 to 9 kHz at powers of 56 to 437 watt. Inverter efficiencies, calculated from experimentally verified loss models, ranged from 89 to 95 percent over the tests. The design target on efficiency is 90 percent. The inverter was demonstrated to supply starting current adequate to overcome the starting friction of the compressor's self-acting gas bearings by a safe margin.

Mccormick, John A.; Valenzuela, Javier A.

1991-01-01

300

Coordination of Series and Shunt Flexible AC Transmission System Devices Based Voltage Source Converter for Improving Power System Stability  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract: Problem statement: Static Synchronous Compensator (STATCOM) and Static Synchronous Series Compensator (SSSC) have been individually applied to improve stability of power system. Approach: This study presents the coordination of a STATCOM and SSSC for improving power system stability. The swing curves of the three phase faulted power system with various cases are tested and compared. Results: The swing curve of system without FACTS devices has...

Prechanon Kumkratug

2011-01-01

 
 
 
 
301

Microfluidic circuit designs for performing electrokinetic manipulations that reduce the number of voltage sources and fluid reservoirs  

Energy Technology Data Exchange (ETDEWEB)

A microfabricated device and method for proportioning and mixing electrokinetically manipulated biological or chemical materials is disclosed. The microfabricated device mixes a plurality of materials in volumetric proportions controlled by the electrical resistances of tributary reagent channels through which the materials are transported. The microchip includes two or more tributary reagent channels combining at one or more junctions to form one or more mixing channels. By varying the geometries of the channels (length, cross section, etc.), a plurality of reagent materials can be mixed at a junction such that the proportions of the reagent materials in the mixing channel depend on a ratio of the channel geometries and material properties. Such an approach facilitates voltage division on the microchip without relying on external wiring schemes and voltage division techniques external to the microchip. Microchannel designs that provide the necessary voltage division to accomplish electrokinetic valving operations using a single voltage source and a switch are also described. In addition, microchannel designs that accomplish fluidic operation utilizing a minimal number of fluidic reservoirs are disclosed.

Jacobson, S.C.; Ramsey, J.M.

2000-05-16

302

MicrofluIdic circuit designs for performing electrokinetic manipulations that reduce the number of voltage sources and fluid reservoirs  

Energy Technology Data Exchange (ETDEWEB)

A microfabricated device and method for proportioning and mixing electrokinetically manipulated biological or chemical materials is disclosed. The microfabricated device mixes a plurality of materials in volumetric proportions controlled by the electrical resistances of tributary reagent channels through which the materials are transported. The microchip includes two or more tributary reagent channels combining at one or more junctions to form one or more mixing channels. By varying the geometries of the channels (length, cross section, etc.), a plurality of reagent materials can be mixed at a junction such that the proportions of the reagent materials in the mixing channel depend on a ratio of the channel geometries and material properties. Such an approach facilitates voltage division on the microchip without relying on external wiring schemes and voltage division techniques external to the microchip. Microchannel designs that provide the necessary voltage division to accomplish electrokinetic valving operations using a single voltage source and a switch are also described. In addition, microchannel designs that accomplish fluidic operation utilizing a minimal number of fluidic reservoirs are disclosed.

Jacobson, Stephen C. (Knoxville, TN); Ramsey, J. Michael (Knoxville, TN)

2000-01-01

303

A method for measuring high resistances with negligible leakage effect using one voltage source and one voltmeter  

Science.gov (United States)

We present a method for measuring high resistances using one voltage source and one voltmeter. With this method, there exist two techniques. One is to measure a high resistance with a much lower resistance and the other is to cancel the leakage effect effectively using two nominally equal resistances without an auxiliary guarding apparatus. To demonstrate the method's validity, a 1 G? resistance was measured using the two techniques replacing a dummy 1 G? resistance as a leakage resistance; the measurement results agree well with the theoretical results within the measurement uncertainty of 3 × 10?6 (k = 2) level. We used the method to determine 10 M?, 1 G? and 1 T? resistances with an active-guard type and a T-type. The best expanded uncertainties at k = 2 from the results were estimated as 0.3 × 10?6, 0.8 × 10?6 and 20 × 10?6, respectively. We also show that while the expanded uncertainty of 70 × 10?6 is obtained using an 81/2 digit digital multimeter, it is improved to 20 × 10?6 using an electrometer with high-input resistance, low bias current and high resolution when the second technique is used to measure high resistances.

Yu, Kwang Min; Kim, Wan Seop; Lee, Sang Hwa; Han, Kwon Soo; Kang, Jeon Hong

2014-07-01

304

ADVANCED COMPUTATIONAL MODEL FOR THREE-PHASE SLURRY REACTORS  

Energy Technology Data Exchange (ETDEWEB)

In this project, an Eulerian-Lagrangian formulation for analyzing three-phase slurry flows in a bubble column was developed. The approach used an Eulerian analysis of liquid flows in the bubble column, and made use of the Lagrangian trajectory analysis for the bubbles and particle motions. The bubble-bubble and particle-particle collisions are included the model. The model predictions are compared with the experimental data and good agreement was found An experimental setup for studying two-dimensional bubble columns was developed. The multiphase flow conditions in the bubble column were measured using optical image processing and Particle Image Velocimetry techniques (PIV). A simple shear flow device for bubble motion in a constant shear flow field was also developed. The flow conditions in simple shear flow device were studied using PIV method. Concentration and velocity of particles of different sizes near a wall in a duct flow was also measured. The technique of Phase-Doppler anemometry was used in these studies. An Eulerian volume of fluid (VOF) computational model for the flow condition in the two-dimensional bubble column was also developed. The liquid and bubble motions were analyzed and the results were compared with observed flow patterns in the experimental setup. Solid-fluid mixture flows in ducts and passages at different angle of orientations were also analyzed. The model predictions were compared with the experimental data and good agreement was found. Gravity chute flows of solid-liquid mixtures were also studied. The simulation results were compared with the experimental data and discussed A thermodynamically consistent model for multiphase slurry flows with and without chemical reaction in a state of turbulent motion was developed. The balance laws were obtained and the constitutive laws established.

Goodarz Ahmadi

2004-10-01

305

ADVANCED COMPUTATIONAL MODEL FOR THREE-PHASE SLURRY REACTORS  

International Nuclear Information System (INIS)

In this project, an Eulerian-Lagrangian formulation for analyzing three-phase slurry flows in a bubble column was developed. The approach used an Eulerian analysis of liquid flows in the bubble column, and made use of the Lagrangian trajectory analysis for the bubbles and particle motions. The bubble-bubble and particle-particle collisions are included the model. The model predictions are compared with the experimental data and good agreement was found An experimental setup for studying two-dimensional bubble columns was developed. The multiphase flow conditions in the bubble column were measured using optical image processing and Particle Image Velocimetry techniques (PIV). A simple shear flow device for bubble motion in a constant shear flow field was also developed. The flow conditions in simple shear flow device were studied using PIV method. Concentration and velocity of particles of different sizes near a wall in a duct flow was also measured. The technique of Phase-Doppler anemometry was used in these studies. An Eulerian volume of fluid (VOF) computational model for the flow condition in the two-dimensional bubble column was also developed. The liquid and bubble motions were analyzed and the results were compared with observed flow patterns in the experimental setup. Solid-fluid mixture flows in ducts and passages at different angle of orientations were also analyzed. The model predictions were compared with the experimental data and good agreement was found. Gravity chute flows of solid-liquid mixtures were also studied. The simulation results were compared with the experimental data and discussed A thermodynamically consistent model for multiphase slurry flows with and without chemical reaction in a state of turbulent motion was developed. The balance laws were obtained and the constitutive laws established

2004-01-01

306

Control of grid integrated voltage source converters under unbalanced conditions: development of an on-line frequency-adaptive virtual flux-based approach  

Energy Technology Data Exchange (ETDEWEB)

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 and reactive power flow, formulated as generalized equations for current reference calculation. A simple, but general, implementation is therefore achieved, where the control objective and the power flow characteristics can be selected according to the requirements of any particular application. Thus, the same control structure can be used to achieve for instance balanced sinusoidal currents or elimination of double frequency active power oscillations during unbalanced conditions. In case of voltage sags, current references corresponding to a specified active or reactive power flow might exceed the current capability of the converter. The limits for active and reactive power transfer during unbalanced conditions have therefore been analyzed, and generalized strategies for current reference calculation when operating under current limitations have been derived. The specified objectives for active and reactive power flow characteristics can therefore be maintained during unbalanced grid conditions, while the average active and reactive power flow is limited to keep the current references within safe values. All concepts and techniques proposed in this Thesis have been verified by simulations and laboratory experiments. The SOGI-based method for Virtual Flux estimation and the strategies for active and reactive power control with current limitation can also be easily adapted for a wide range of applications and can be combined with various types of inner loop control structures. Therefore, the proposed approach can potentially be used as a general basis for Virtual Flux-based voltage-sensor-less operation of VSCs under unbalanced grid voltage conditions.(Author)

Suul, Jon Are

2012-03-15

307

Sinusoidal PAM-PWM inverter. Seigenha shutsuryoku PAM gata PWM inverter no ichihoshiki  

Energy Technology Data Exchange (ETDEWEB)

In the AC-AC power conversion system connecting two alternating current systems such as commercial AC lines and AC motors, etc., a PAM-PWM controlling system was proposed to obtain sinusoidal output by adding an operation to improve the waveform of inverter output to that of a DC-DC converter while making the inverter get a wide period of repose, then the output voltage waveform was analysed. From the result of analysis, it was found out that the component included in the output voltage waveform consisted of the fundamental component and the sidebands of the carrier frequency and did not contain higher harmonics; also, the amplitude of the fundamental component increased 15 % more than that of a conventional sine-wave inverter, etc. Furthermore, a trial manufacture and an experiment of a sinusoidal output PAM inverter being composed of MOSFET were carried out. As a result, it was found out that the size of the heat dissipating equipment of the inverter could be minimized since each converter arm reposed the commutative operation during 240[degree] of the output cycle and the heat generated in the inverter was reduced. 10 refs., 9 figs., 1 tab.

Inoue, M.; Taniguchi, K. (Osaka Inst. of Technology, Osaka (Japan))

1992-09-20

308

Prediction of power losses in silicon iron sheets under PWM voltage supply  

International Nuclear Information System (INIS)

The behavior of iron losses in silicon iron steels submitted to a PWM voltage is studied. The influence of modulation parameters (the depth of modulation and the number of eliminated harmonics) is clarified. In particular, the idea of an equivalent alternating pulse voltage that gives the same iron losses as the PWM voltage is established. An estimation formula for iron losses under the PWM voltage is developed based on the loss separation model and the voltage form factor. ((orig.))

1994-05-01

309

Controlling DC Motor using Microcontroller (PIC16F72 with PWM  

Directory of Open Access Journals (Sweden)

Full Text Available 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. Togenerate PWM signals we use PIC16F72 microcontroller.

Shruti Shrivastava, Jageshwar Rawat, Amit Agrawal

2012-12-01

310

Hysteresis in Analytical Solutions for Three-phase Flow  

Science.gov (United States)

Hysteresis in relative permeability is a widely-recognized phenomenon that impacts oil recovery in water and gas (WAG) injection. Several authors (1-3) have constructed analytical solutions for two-phase oil/water or gas/water flow in enhanced oil recovery however, analytical solutions have not previously been constructed for the three-phase flow problem for immiscible water, oil and gas including hysteresis. In this work analytical solutions are constructed for water and gas floods in a previously water-flooded oil reservoir with and without hysteresis. A simplified model is used in the analysis that qualitatively captures the behavior of oil-phase hysteresis for repeated water imbibition and drainage cycles. Many of the displacements considered have a reversal of flow direction within the displacement, requiring a matching condition to be enforced between the imbibition and drainage relative permeability curves at the point of flow reversal. A suitable matching criterion for the hysteretic curves is presented. A single water/gas injection mixture is considered, with varying initial oil and water volumes present in the reservoir. When hysteresis occurs in a displacement the entire saturation path depends on the initial volumes of oil and water present at the onset of WAG flooding. When hysteresis is ignored most of the displacement is identical for a large range of initial oil and water mixtures, with only the velocity of the leading shock changing. For the displacements which only encounter drainage of the water phase, solutions with and without hysteresis are identical. 1) K. M. Furati, ``Effects of Relative Permeability History Dependence on Two-Phase Flow in Porous Media,'' Transport in Porous Media 28: 181-203, 1997. 2) B. Plohr, D. Marchesin, P. Bedrikovetsky and P. Krause, ``Modeling hysteresis in porous media flow via relaxation,'' Computational Geosciences 5: 225-256, 2001. 3) F. M. Van Kats and C. J. Van Duijn, ``A Mathematical Model for Hysteretic Two-Phase Flow in Porous Media,'' Transport in Porous Media 43: 239-263, 2001.

Lambers, J. V.; LaForce, T.

2011-12-01

311

Hysteresis modeling of synchronous reluctance motor considering PWM input voltage  

Science.gov (United States)

This paper deals with the hysteresis characteristics analysis in PWM fed synchronous reluctance motor (SynRM) using a coupled finite element method (FEM) and Preisach's modeling, which is presented to analyze the characteristics under the effect of saturation and hysteresis loss. With regard to the PWM characteristics, a vector control inverter is combined with an analysis tool. Also, a moving mesh technique is used with regard to rotation due to velocity. The focus of this paper is the applied method of Preisach modeling for rotating machines and the characteristics analysis of a SynRM using the proposed method of analysis. For the propriety of proposed method of analysis, TMS320C31 DSP-installed experimental devices are used. And then, computer simulation and experimental result for the i- ? loci, speed, current response, show the propriety of the proposed method. The characteristic analysis is performed in relation to the maximum efficiency condition for a SynRM in simulation and experiment.

Lee, J. H.; Kim, J. C.; Hyun, D. S.

2000-01-01

312

Effects of 60Co ?-rays on PWM and LPS induced lymphocytes  

International Nuclear Information System (INIS)

The relationship between lymphocytes induced by PWM and LPS was investigated by means of 3H-TdR and 14C-UR incorporation. The study showed that in votro, PWM-induced cells were able to promote the stimulating effect of LPS to B lymphocyte. The stimulating effect of PWM-induced cells was obviously weakened after PWM cells being irradiated with ?-rays. When PWM-induced cells and LPS-induced cells were incubated together, with one kind of cells exposed to 60Co ?-rays, incorporation value of 3H-TdR became much smaller and the synergetic function disappeared, especially, when PWM-induced cells were irradiated. For patients suffering from carcinoma of nasopharynx, when treated with 60Co ?-rays, the incorporation value in LPS-induced cells approached normal level, while the incorporation value in PWM-induced cells reduced significantly and the stimulating effect of PWM-induced cells on LPS-induced cells became much weaker. The fact described above demonstrated that PWM-induced cells have the function of T-helper cells and play a more important role in the synergy than LPS induced cells

1987-01-01

313

Investigation of iron loss under PWM voltage excitation in various size strip-wound toroidal cores  

Energy Technology Data Exchange (ETDEWEB)

The PWM inverters are widely used when variable speed and UPS are required. Due to distortion in PWM flux waveform extra power losses occur in magnetic cores. The iron loss of three types of grain-oriented 3% Si-Fe toroidal cores was measured by a highly accurate measurement system under PWM and sinusoidal voltage excitation at different flux densities. The loss increase under PWM excitation was found higher at high flux densities due to higher harmonic distortion and different magnetisation process. (orig.)

Tutkun, N. [Karaelmas Univ., Faculty of Engineering, Div. of Electrical and Electronic, Zonguldak (Turkey); Kockar, H. [Balikesir Univ., Faculty of Science, Balikesir (Turkey); Demirci, R. [Abant Izzet Baysal Univ., Faculty of Technical Education, Electrical and Electronic Dept., Duzce (Turkey)

2000-08-01

314

Neural network based PWM AC chopper fed induction motor drive  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 driv...

Venkatesan Jamuna; Sathi Reddy Rama

2009-01-01

315

Power electronic converters PWM strategies and current control techniques  

CERN Document Server

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.

Monmasson, Eric

2013-01-01

316

Algorithms of Space Vector PWM in Overmodulation Area  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this paper is the comparison and evaluation of different space vector PWM (SVPWM) strategies enabling the continuous transition from the linear modulation to the six-step mode. One of the important factors to be explored is the frequency analysis of the motor quantities in order to be able to evaluate the possible impact of the drive on the traction mains – specifically the impact on the railway signaling

Zdenek Peroutka; Tomas Glasberger

2006-01-01

317

Algorithms of Space Vector PWM in Overmodulation Area  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this paper is the comparison and evaluation of different space vector PWM (SVPWM strategies enabling the continuous transition from the linear modulation to the six-step mode. One of the important factors to be explored is the frequency analysis of the motor quantities in order to be able to evaluate the possible impact of the drive on the traction mains – specifically the impact on the railway signaling

Zdenek Peroutka

2006-01-01

318

Algorithms of space vector PWM in overmodulation area  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this paper is the comparison and evaluation of different space vector PWM (SVPWM) strategies enabling the continuous transition from the linear modulation to the six-step mode. One of the important factors to be explored is the frequency analysis of the motor quantities in order to be able to evaluate the possible impact of the drive on the traction mains – specifically the impact on the railway signaling.

Peroutka, Z.; Glasberger, T.

2006-01-01

319

HVDC with voltage source converters and extruded cables for up to {+-}300 kV and 1000 MW  

Energy Technology Data Exchange (ETDEWEB)

Recent developments in voltage source converter and high voltage direct current (VSC HVDC) systems were discussed. VSC HVDC systems allow connections in or between networks via low-weight extruded cables. Connections can be made at costs comparable to overhead AC transmission lines. VSC HVDC systems can prevent fault propagation, increase low frequency stability, reduce network losses, and increase voltage stability. New research has meant that the system's maximum power handling has been increased to at least 1000 MWs. This paper explored new research developments in 4 key areas: (1) IGBT valves, (2) DC cable systems, (3) main circuit of converter stations, and (4) control systems. It was noted that the VSC valves now have improved current handling, lower losses, better cooling and better voltage sharing. A larger presspack IGBT gives higher converter current handling. The cable system has been expanded in both voltage capacity and laying depth. Both flexible and stiff joints have now been developed for the polymeric extruded cables. Testing of the cable system has verified a 300 kVdc capability and a laying depth larger than 2000 m. Converter main circuits have been modified for improved cost and lower losses. The control system has been optimized with a new black-start control which can provide full support during grid restoration processes. As a result of the modifications, the range of possible applications for VSC HVDC can be expanded to large scale transmission. The system is able to transmit large amount of power long-distance, and can also be used to add new transmission lines where restrictions concerning right-of-way have caused difficulties. It was concluded that VSC HVDC provides full power flow control in both directions, voltage stabilization via continuous reactive power control, and minimized disturbances due to fault propagation. 16 refs., 3 tabs., 6 figs.

Jacobson, B.; Jiang-Hafner, Y.; Rey, P.; Asplund, G. [ABB Power Technologies, Ludvika (Sweden); Jeroense, M.; Gustafsson, A.; Bergkvist, M. [ABB Power Technologies, Karlskrona (Sweden); Trinh, T.N. [ABB Inc., Montreal, PQ (Canada)

2006-07-01

320

Dynamics of IGBT based PWM Converter A Case Study  

Directory of Open Access Journals (Sweden)

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.

Vijay Shukla

2012-04-01

 
 
 
 
321

Design and Implementation of carrier based Sinusoidal PWM Inverter  

Directory of Open Access Journals (Sweden)

Full Text Available SPWM or sinusoidal pulse width modulation is widely used in power electronics to digitize the power so that a sequence of voltage pulses can be generated by the on and off of the power switches. The pulse width modulation inverter has been the main choice in power electronic for decades, because of its circuit simplicity and rugged control scheme SPWM switching technique is commonly used in industrial applications SPWM techniques are characterized by constant amplitude pulses with different duty cycle for each period. The width of this pulses are modulated to obtain inverter output voltage control and to reduce its harmonic content. Sinusoidal pulse width modulation or SPWM is the mostly used method in motor control and inverter application. In this development a unipolar and bipolar SPWM voltage modulation type is selected because this method offers the advantage of effectively doubling the switching frequency of the inverter voltage, thus making the output filter smaller, cheaper and easier to implement. Conventionally, to generate this signal, triangle wave as a carrier signal is compared with the sinusoidal wave, whose frequency is the desired frequency. In this paper single-phase inverters and their operating principles are analyzed in detail. The concept of Pulse Width Modulation (PWM for inverters is described with analyses extended to different kinds of PWM strategies. Finally the simulation results for a single-phase inverter (unipolar using the PWM strategies described are presented [1],[2],[3].

PANKAJ H ZOPE

2013-04-01

322

Consideration on PWM control for neutral point clamped inverter. Chuseiten clamp shiki inverter no PWM seigyoho no kento  

Energy Technology Data Exchange (ETDEWEB)

Control characteristics of neutral point clamped (NPC) inverters with three level output voltages were studied which have such great advantages as higher output voltage and lower ripple currents, and a new PWM control method covering all the operating ranges of the NPC inverter was proposed. The NPC inverter could not control pulse-wise voltage for a small reference through PWM control on account of Me minimum on-time of elements. The new control method was thus proposed as preventive measures in which the voltage reference for PWM control was divided into positive and negative ones, and by adding a constant bias voltage to them, the pulse width of output voltages longer than the minimum on-time was constantly ensured. In addition, as the result of comparison between the NPC inverter and a conventional bridge inverter, the NPC inverter was expected to be effective for driving without any transformers of MVA class large-capacity AC motors 6 refs., 11 figs., 1 tab.

Tanaka, s.; Miura, K.; Watanabe, T.; Tadakuma, S. (Toshiba Corp., Tokyo (Japan)); Ikeda, H. (Railway Technical Research Institute, Tokyo (Japan))

1992-06-20

323

30 CFR 75.901 - Protection of low- and medium-voltage three-phase circuits used underground.  

Science.gov (United States)

...medium-voltage three-phase circuits used...medium-voltage three-phase circuits used...medium-voltage three-phase alternating-current...which shall be grounded through a suitable...representative may permit ungrounded low- and...

2009-07-01

324

Control of a Three Phase Induction Motor using Single Phase Supply  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In Industrial applications, two forms of electrical energy are used: Direct Current (DC) and Alternating Current (AC). Usually constant voltage, constant frequency Single-Phase or Three-Phase AC is readily available. However, for different applications different forms, magnitudes and/or frequencies are required. This paper proposes how the Three-Phase inductive load is run by a Single-Phase supply by using Cycloconverter and a Scott-T connected Transformer. The controlling of a ThreePhase Ind...

2012-01-01

325

Generalisation of Helmholtz-Thevenin theorem to three-phase electrical circuits  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The scope of this paper is to determine the generalized form for equivalent tension generator theorem (Helmholtz-Thevenin theorem) for three-phase electrical circuit. Any complicated electrical power systems we can reduce depending on any three-phase electrical consumer to a three-phase electrical generator that has certain internal impedance. Starting with this assumption, we have demonstrated the way to obtain the electromotive voltages for an equivalent generator and its ...

Mihai, Gheorghe

2009-01-01

326

Control of Power Electronic Converters in Distributed Power Generation Systems :Evaluation of Current Control Structures for Voltage Source Converters operating under Weak Grid Conditions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The performance of different current controller structures for Voltage Source Converters (VSC) under weak grid conditions caused by large grid impedance is investigated. The VSC is synchronized to the grid by a Phase Locked Loop (PLL). Current control techniques and PLL techniques for handling both symmetrical and asymmetrical conditions are presented and discussed. The investigated current control structures are; the conventional Proportional Integral (PI)-controller in the synchronous rotat...

Midtsund, Tarjei

2010-01-01

327

Control of Power Electronic Converters in Distributed Power Generation Systems : Evaluation of Current Control Structures for Voltage Source Converters operating under Weak Grid Conditions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The performance of different current controller structures for Voltage Source Converters (VSC) under weak grid conditions caused by large grid impedance is investigated. The VSC is synchronized to the grid by a Phase Locked Loop (PLL). Current control techniques and PLL techniques for handling both symmetrical and asymmetrical conditions are presented and discussed. The investigated current control structures are; the conventional Proportional Integral (PI)-controller in the synchronous rotat...

Midtsund, Tarjei

2010-01-01

328

Three-phase gas-liquid-liquid flows in the steady and transient states  

International Nuclear Information System (INIS)

Three-phase (gas-liquid-liquid) flows are important in a number of industrial contexts. The manifestations and nature of three-phase flows are discussed and recent work at Imperial College is reviewed. Flow patterns in three-phase flows are complex and vary considerably from system to system. Time average values of pressure drop and hold-up show characteristic peaks as a function of 'water cut' (fraction by volume of water in the liquid phase). Measurements on stratified and slug flows are reviewed and cases of transient flows (where the input flow is changed suddenly) are described. Finally, predictions methods for three-phase flows are reviewed

2005-05-01

329

Critical slip of three-phase cage induction motor supplied from limited power source  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The peculiarities and characteristics of a cage induction motor supplying from limited power source (mobile electric power station, diesel power plant, wind power station and etc.) change virtually in comparison with the case when motor is supplied from unlimited voltage source. The critical slip expression of the cage induction motor operating from the limited power-supply source taking into account the inner complex impedance of power-supply source and other cable parameters has been derive...

Gec?ys, S.

2007-01-01

330

Spread Spectrum Modulation by Using Asymmetric-Carrier Random PWM  

DEFF Research Database (Denmark)

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 is very effective and is independent from the modulation index. The flat motor current spectrum generates an acoustical noise close to the white noise, which improves 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 both open and closed loop motor control applications.

Mathe, Laszlo; Lungeanu, Florin

2012-01-01

331

Soft Switched Multi-Output PWM DC-DC Converter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, a new soft switched cell that overcomes most of the drawbacks of the normal "hard switched-pulse width modulation" converter is proposed to contrive a new family of soft switched PWM converters. All of the semiconductor devices in this converter are turned on and off under exact or near zero voltage switching (ZVS) and/or zero current switching (ZCS). No additional voltage and current stresses on the main switch and main diode occur. A push-pull converter equipped with the prop...

Rashmi Sharma

2013-01-01

332

Power Conditioning System for SMES Using Thyristor PWM Converter  

Energy Technology Data Exchange (ETDEWEB)

This paper proses a new power conditioning system for the SMES composed of a thyristor PWM converter with a resonant commutation circuit. The operation of the proposed system and the dynamic interaction between SMES and the power system is analyzed by a theoretical approach with equivalent circuits and verified by computer simulations with EMTP, considering a typical 154kV power system. The proposed system can provide a solution for the power factor regulation and harmonic level reduction in the ac terminal with low-cost system configuration. (author). 7 refs., 10 figs.

Han, Byung Moon [Myongji University, Seoul (Korea)

2001-06-01

333

Transient Analysis of Three-Phase Self Excited Induction Generator Using New Approach  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, Matlab/Simulink based new saturation model is proposed to investigate the transient performance of a three-phase induction machine. The model as proposed is used to predict the transient performance of three-phase induction generator under different operating conditions. Closeness of simulated results with experimental results on a test machine proves the effectiveness of the proposed model.

2012-01-01

334

Three-phase region of D/sub 2/-DT-T/sub 2/  

Energy Technology Data Exchange (ETDEWEB)

Analogous to the triple point of a pure substance are a binary mixture's triple line and a ternary mixture's three-phase surface, where pressure, temperature, and composition must all be considered. The first three-phase study on a ternary hydrogen system, D/sub 2/-DT-T/sub 2/, is reported.

Souers, P.C.; Kelly, E.M.; Roberts, P.E.; Fearon, D.; Tsugawa, R.T.

1977-06-23

335

Three-Phase and Six-Phase AC at the Lab Bench  

Science.gov (United States)

Utility companies generate three-phase electric power, which consists of three sinusoidal voltages with phase angles of 0 degrees, 120 degrees, and 240 degrees. The ac generators described in most introductory textbooks are single-phase generators, so physics students are not likely to learn about three-phase power. I have developed a simple way…

Caplan, George M.

2009-01-01

336

PWM Based Automatic Closed Loop Speed Control of DC Motor  

Directory of Open Access Journals (Sweden)

Full Text Available The electric drive systems used in many industrial applications require higher performance, reliability, variable speed due to its ease of controllability. The speed control of DC motor is very crucial in applications where precision and protection are of essence. Purpose of a motor speed controller is to take a signal representing the required speed and to drive a motor at that speed. Microcontrollers can provide easy control of DC motor. Microcontroller based speed control system consist of electronic component, microcontroller and the LCD. In this paper, implementation of the ATmega8L microcontroller for speed control of DC motor fed by a DC chopper has been investigated. The chopper is driven by a high frequency PWM signal. Controlling the PWM duty cycle is equivalent to controlling the motor terminal voltage, which in turn adjusts directly the motor speed. This work is a practical one and high feasibility according to economic point of view and accuracy. In this work, development of hardware and software of the close loop dc motor speed control system have been explained and illustrated. The desired objective is to achieve a system with the constant speed at any load condition. That means motor will run at a fixed speed instead of varying with amount of load.

Atul Kumar Dewangan, Nibbedita Chakraborty, Sashi Shukla, Vinod Yadu

2012-04-01

337

Soft-switching PWM full-bridge converters topologies, control, and design  

CERN Document Server

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

Ruan, Xinbo

2014-01-01

338

Novel, Four-Switch, Z-Source Three-Phase Inverter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a new z-source three phase inverter topology. The proposed topology combines the advantages of a traditional four-switch three-phase inverter with the advantages of the z impedance network (one front-end diode, two inductors and two X connected capacitors). This new topology, besides the self-boost property, has low switch count and it can operate as a buck-boost inverter. In contrast to standard four-switch three-phase inverter which operates at half dc input voltage the ...

Antal, Robert; Muntean, Nicolae; Boldea, Ion; Blaabjerg, Frede

2011-01-01

339

Efficiency analysis on a two-level three-phase quasi-soft-switching inverter  

DEFF Research Database (Denmark)

When designing an inverter, an engineer often needs to select and predict the efficiency beforehand. For the standard inverters, plenty of researches are analyzing the power losses and also many software tools are being used for efficiency calculation. In this paper, the efficiency calculation for non-conventional inverters with special shoot-through state is introduced and illustrated through the analysis on a special two-level three-phase quasi-soft-switching inverter. Efficiency comparison between the classical two-stage two-level three-phase inverter and the two-level three-phase quasi-soft-switching inverter is carried out. A 10 kW/380 V prototype is constructed to verify the analysis. The experimental results show that the efficiency of the new inverter is higher than that of the traditional two-stage two- level three-phase inverter.

Geng, Pan; Wu, Weimin

2013-01-01

340

Design of Materials with Extreme Thermal Expansion Using a Three-Phase Topology Optimization Method.  

Science.gov (United States)

Composites with extremal or unusual thermal expansion coefficients are designed using a three-phase topology optimization method. The composites are made of two different material phases and a void phase. The topology optimization method finds the distrib...

O. Sigmund S. Torquato

1996-01-01

 
 
 
 
341

Novel, Four-Switch, Z-Source Three-Phase Inverter  

DEFF Research Database (Denmark)

This paper presents a new z-source three phase inverter topology. The proposed topology combines the advantages of a traditional four-switch three-phase inverter with the advantages of the z impedance network (one front-end diode, two inductors and two X connected capacitors). This new topology, besides the self-boost property, has low switch count and it can operate as a buck-boost inverter. In contrast to standard four-switch three-phase inverter which operates at half dc input voltage the proposed four-switch z-source inverter, by self boosting, brings the output voltage at same (or higher) value as in six switch standard three-phase inverter. The article presents the derivation of the equations describing the operation of the converter based on space vector analysis, validation through digital simulations in PSIM and preliminary experimental results on a laboratory setup with a dsPIC30F3011 digital signal processor.

Antal, Robert; Muntean, Nicolae

2010-01-01

342

Control of a Three Phase Induction Motor using Single Phase Supply  

Directory of Open Access Journals (Sweden)

Full Text Available In Industrial applications, two forms of electrical energy are used: Direct Current (DC and Alternating Current (AC. Usually constant voltage, constant frequency Single-Phase or Three-Phase AC is readily available. However, for different applications different forms, magnitudes and/or frequencies are required. This paper proposes how the Three-Phase inductive load is run by a Single-Phase supply by using Cycloconverter and a Scott-T connected Transformer. The controlling of a ThreePhase Induction Motor is done by Frequency variable method. Single-Phase to Three-Phase for motors offered by using high in performance, low on maintenance and is used to reduce of breakdown of electrical equipment, our range is also suitable for saving energy and require low maintenance.

G. R. Sreehitha, A. Krishna Teja, Kondenti. P. Prasad Rao

2012-06-01

343

Calculation methods for short-circuit currents in three-phase bridge rectifier circuits  

Science.gov (United States)

Matrix methods were used to calculate external short circuit currents in three-phase bridge rectifiers. Transient short circuit currents of rectifiers with dc reactances and resistances can be calculated using the matrix methods.

Fan, Y.

1985-05-01

344

Heat Transfer Characteristics of a Three-Phase Volume Boiling Direct Contact Heat Exchanger.  

Science.gov (United States)

The advantages of direct contact heat transfer over heat transfer utilizing conventional metallic heat exchangers are listed. The performance characteristics of a three-phase direct contact heat exchanger in near counterflow operation were evaluated using...

C. K. Blair R. F. Boehm H. R. Jacobs

1976-01-01

345

ELECTROMAGNETIC CALCULATION OF THREE-PHASE ASYNCHRONOUS MOTORS WITH A SIX-PHASE WINDING  

Directory of Open Access Journals (Sweden)

Full Text Available Features of electromagnetic computation of three-phase asynchronous motors with a six-phase winding in the stator are described. Experimental data on a conveyor motor with two six-phase windings are given.

S.Yu. Polez?n

2013-02-01

346

A reverse mode of three-phase asynchronous motors with hexaphase windings  

Directory of Open Access Journals (Sweden)

Full Text Available A reverse operation feasibility in three-phase asynchronous motors with the stator hexaphase windings is proved. In the reverse mode, the hexaphase windings are shown to keep all their declared advantages.

V.D. Lushchyk

2014-04-01

347

Investigation of a three-phase-single-phase induction electric drive under stochastic loads  

Directory of Open Access Journals (Sweden)

Full Text Available A control system for a three-phase-single- phase induction electric drive with a controlled phase-shifting module is developed and studied to result in a symmetric regime under stochastic load variations.

Yu.V. Shurub

2014-04-01

348

Fast Unbalanced Three-phase Adjustment Base on Single-phase Load Switching  

Directory of Open Access Journals (Sweden)

Full Text Available To balance three-phase loads in distribution network with abundant of single-phase loads, a new wiring method and three-phase loads adjustment policy was proposed in this paper. In the wiring method, a single-phase load was connected with phase A, B and C of trunk line by a controller. When the load of trunk line was unbalanced, the controller will switch the connected single-phase loads from one phase to another to balance it. The minimum count of loads adjustment algorithm and the most balance adjustment algorithm were proposed, which can adjust the three-phase load of trunk line to roughly balance automatically. This method can solve the serious three-phase unbalance problems of the trunk lines with aboundant of single-phase loads. It may instead of capacitive compensation in low voltage distribution network to improve power quality and reduce network losses.  

Yanwei Zheng

2013-08-01

349

Genetic Algorithm based Steady-State Analysis of Three-Phase Self-Excited Induction Generators  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a genetic algorithm based steady-state analysis of a three-phase self-excited induction generator (SEIG) for wind energy conversion. A generalized mathematical model based on inspection is developed for a three-phase induction generator for steady-state analysis. The proposed mathematical model is quite general in nature and can be implemented for any type of load such as resistive or reactive load. The proposed model completely avoids the tedious work of segregating rea...

2012-01-01

350

A Three-Phase Bidirectional DC-DC Converter for Automotive Applications  

Energy Technology Data Exchange (ETDEWEB)

This paper presents a three-phase soft-switching, bidirectional dc-dc converter for high-power automotive applications. The converter employs dual three-phase active bridges and operates with a novel asymmetrical but fixed duty cycle for the top and bottom switches of each phase leg. Simulation and experimental data on a 6-kW prototype are included to verify the novel operating and power flow control principles.

Su, Gui-Jia [ORNL; Tang, Lixin [ORNL

2008-01-01

351

One-, two- and three-phase viscosity treatments for basaltic lava flows  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Lava flows comprise three-phase mixtures of melt, crystals, and bubbles. While existing one-phase treatments allow melt phase viscosity to be assessed on the basis of composition, water content, and/or temperature, two-phase treatments constrain the effects of crystallinity or vesicularity on mixture viscosity. However, three-phase treatments, allowing for the effects of coexisting crystallinity and vesicularity, are not well understood. We investigate existing one- and two-phase treatments u...

Harris, Andrew J. L.; Allen, John S.

2008-01-01

352

Direct torque control for dual three-phase induction motor drives  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A direct torque control (DTC) strategy for dual three-phase induction motor drives is discussed in this paper. The induction machine has two sets of stator three-phase windings spatially shifted by 30 electrical degrees. The DTC strategy is based on a predictive algorithm and is implemented in a synchronous reference frame aligned with the machine stator flux vector. The advantages of the discussed control strategy are constant inverter switching frequency, good transient and steady-state per...

Farina, Francesco; Profumo, Francesco; Griva, Giovanni Battista; Tenconi, Alberto; Bojoi, Iustin Radu

2005-01-01

353

Particle trajectories in a three phase common enclosure gas insulated busduct with Monte Carlo technique  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The excellent insulation properties of compressed sulphur hexaflouride are adversely affected by metallic particle contamination in practical gas insulated systems. The movement of such particles is random and the particles play a crucial role in determining the insulation behavior of GIS. A Three-phase enclosure-type gas insulated bus (GIB) has widely been applied to minimize the installation space of a substation. To determine the particle trajectories in a three-phase common enclosure Gas ...

2008-01-01

354

A Novel Unit Power Factor Rectifier Based on Three-phase Digital PLL  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A novel three-phase phase-locked loop solution is proposed based on D-Q transformation aiming at the AC-DC rectifier with high efficiency and high power factor. The phase-locked loop is implemented digitally using the Xilinx blockset integrated with Matlab/Simulink. The three-phase digital phase-locked loop (TDPLL) is elaborately designed with the parameters defined in detail. The AC-DC converter (rectifier) model with the ...

Xuegui Zhu; Zhihong Fu; Xiangfeng Su

2013-01-01

355

Surface Effect on Three Phase Lines of Low-Ohmic Furnaces  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The article another option of using numerical method of elementary conductors in surface effect three-phase supply linesfor low-ohmic furnaces. Impedance asymmetry of three-phase supply lines of different conductor profiles and various spaceconfigurations is analysed following to the author`s article published in this journal (Vol. 2/2003, No. 2, pg. 42). Options of reducingunfavourable effect of so called live and dead phase and their utilization in design and construction of mentioned lines...

2004-01-01

356

Fuzzy Logic Closed Loop Control of 5 level MLI Driven Three phase Induction motor  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper deals about fuzzy logic control of closed loop controlled five level Multi Level Inverter (MLI) driven three phase induction motor. Three phase Induction motor is most widely used drive in Industries, so needs proper control of speed. Induction motor is fed from five level multilevel inverter which is controlled by fuzzy logic. The closed loop consists of two loops. First inner loop is current loop and second outer loop is speed loop. The torque is varied at different times and cor...

Mulukutla Venkata Subramanyam; Prasad, P. V. N.; Poornachandra Rao, G.

2013-01-01

357

The effect of saturation history on three-phase relative permeability: An experimental study  

Science.gov (United States)

investigate the effect of different saturation histories relevant to various oil displacement processes (including secondary and tertiary gas injections) on three-phase gas/oil/brine relative permeabilities of water-wet sandstone. It is found that three-phase water (wetting phase) relative permeability is primarily a function of water saturation and shows no dependency upon saturation history. Three-phase gas (nonwetting phase) relative permeability is also a function of gas saturation as well as the direction of gas saturation change. Three-phase relative permeability to oil (intermediate-wetting phase) appears to depend on all phase saturations, and saturation history have no significant impact on it. Three-phase oil relative permeability shows weak sensitivity to initial oil saturation prior to gas injection. The functional forms of oil relative permeability with saturation, particularly at low oil saturations, are also examined. It is observed that, at high oil saturations where networks of oil-filled elements govern oil flow, oil relative permeability exhibits a quartic form with oil saturation >(kro?So4>) whereas, at low oil saturations where flow is believed to be controlled by layer drainage, it shows a quadratic form >(kro?So2>). The quadratic form of three-phase oil relative permeability is consistent with the theoretical interpretation of layer drainage at the pore scale.

Alizadeh, A. H.; Piri, M.

2014-02-01

358

Harmonic evaluation of an NPC PWM inverter employing the harmonic distortion determining factor  

Energy Technology Data Exchange (ETDEWEB)

This paper describes a new harmonic evaluation scheme of neutral-point-clamped (NPC) PWM inverters. The scheme uses the harmonic distortion determining factor (HDDF). As the HDDF represents the intrinsic spectral property of PWM schemes and is almost independent of the operating Conditions, it is quite useful for predicting the harmonic properties in ac drives. If HDDF values for individual PWM schemes are known, the approximate harmonic characteristics, such as the current harmonics or the torque ripples, can be easily calculated using HDDF values. In this paper, HDDF values of carrier-based five types of NPC-PWM schemes are given, and the approximate harmonic characteristics calculated by the HDDF approach are discussed.

Fukuda, Shoji; Suzuki, Kunio [Hokkaido Univ., Sapporo (Japan); Iwaji, Yoshitaka [Hitachi, Ltd. (Japan)

1995-12-31

359

PWM Switching Frequency Effects on Eddy Current Sensors for Magnetically Suspended Flywheel Systems  

Science.gov (United States)

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.

Jansen, Ralph; Lebron, Ramon; Dever, Timothy P.; Birchenough, Arthur G.

2003-01-01

360

A PWM transistor inverter for an ac electric vehicle drive  

Science.gov (United States)

A prototype system consisting of closely integrated motor, inverter, and transaxle has been built in order to demonstrate the feasibility of a three-phase ac transistorized inverter for electric vehicle applications. The microprocessor-controlled inverter employs monolithic power transistors to drive an oil-cooled, three-phase induction traction motor at a peak output power of 30 kW from a 144 V battery pack. Transistor safe switching requirements are discussed, and a circuit is presented for recovering trapped snubber inductor energy at transistor turn-off.

Slicker, J. M.

1981-10-01

 
 
 
 
361

Voltage Balancing in Diode Clamped Multilevel Inverter Using Sinusoidal PWM  

Directory of Open Access Journals (Sweden)

Full Text Available Multilevel inverters offer several advantages compared to the conventional 3-phase bridge inverter in terms of lower dv/dt stresses, lower electromagnetic compatibility, smaller rating and better output features. This project presents a 9-level diode Clamped inverter using Sinusoidal pulse width Modulation techniques as the control strategies. The algorithm has been developed within the carrier-based PWM framework to facilitate its implementation in diode clamped converters with three or more levels. A simulation model of 9-level DCMI has been designed and developed. The results obtained from the simulation model have been compared with the 3-level and 5-level diode clamped inverter. By increasing the level of inverter, effective balancing in line voltage and reduced THD is obtained.

S.Shalini

2013-12-01

362

Soft switching PWM isolated boost converter for fuel cell application  

Energy Technology Data Exchange (ETDEWEB)

In this paper a new soft switching isolated boost type converter is introduced for fuel cell applications. In this converter zero voltage switching condition is achieved for the main switches and the auxiliary circuit is also soft switched. Also, the converter control circuit is simple PWM. Due to achieved soft switching condition, the converter can operate at high powers which make it suitable for fuel cell applications. Also, due to high voltage gain of the converter and isolation between input and output sources, the converter is a proper choice for the interface of fuel cell and inverters. Furthermore, the input current of the converter (current drained from the fuel cell) is almost constant since it is a boost type converter. The converter is analyzed and the simulation results presented confirm the validity of theoretical analysis. (orig.)

Rezaei, Majid [Isfahan Subsea R and D Institute (Iran, Islamic Republic of)

2010-07-01

363

Led spectral and power characteristics under hybrid PWM/AM dimming strategy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 thermall...

Beczkowski, Szymon; Munk-nielsen, Stig

2010-01-01

364

PWM Inverter-Fed Induction Motor-Based Electrical Vehicles Fault-Tolerant Control  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper proposes a fault-tolerant control scheme for PWM inverter-fed induction motor-based electric vehicles. The proposed strategy deals with power switch (IGBTs) failures mitigation within a reconfigurable induction motor control. In a vehicle context, 4-wire and 4-leg PWM inverter topologies are investigated and their performances discussed. Two topologies exploit the induction motor neutral accessibility for fault-tolerant purposes. The 4-wire topology uses then classical hysteresis c...

Tabbache, Bekheira; Benbouzid, Mohamed; Kheloui, Abdelaziz; Bourgeot, Jean-matthieu; Mamoune, Abdeslam

2013-01-01

365

Voltage balancing scheme for the multilevel flying capacitor converter using phase-shifted PWM  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In flying capacitor (FC) converters, phase-shifted pulse-width modulation (PS-PWM) provides natural voltage balancing. However, for a practical application, a more robust balancing mechanism of maintaining the FC voltages at the desired values is required. This paper proposes a new closed-loop voltage balancing method for multilevel FC converters using PS-PWM. The proposed method balances the voltages of the FCs by modifying the duty cycle of each switch of the FC converter using a proportion...

Ghias, Amer M. Y. M.; Pou Fe?lix, Josep; Ciobotaru, M.; Agelidis, Vassilios

2012-01-01

366

Modeling and control of a three-phase isolated grid-connected converter for photovoltaic applications Modelagem e controle de um conversor trifásico conectado à rede para aplicações fotovoltáica  

Directory of Open Access Journals (Sweden)

Full Text Available This paper describes the modeling and control of a three-phase grid-connected converter fed by a photovoltaic array. The converter is composed of an isolated DC-DC converter and a three-phase DC-AC voltage source inverter The converters are modeled in order to obtain small-signal transfer functions that are used in the design of three closed-loop controllers: for the output voltage of the PV array, the DC link voltage and the output currents. Simulated and experimental results are presented.Este artigo descreve a modelagem e o controle de um conversor trifásico conectado à rede alimentado por um conjunto fotovoltaico. O conversor é composto de um estágio CC-CC isolado um estágio CC-CA. São obtidas funções de transferência com as quais são projetados três sistemas de controle em malha fechada: um para a tensão de entrada do arranjo de painéis solares, um para a tensão do do barramento de tensão contínua e outro para as correntes trifásicas de saída.

Marcelo Gradella Villalva

2011-06-01

367

Modeling and control of a three-phase isolated grid-connected converter for photovoltaic applications / Modelagem e controle de um conversor trifásico conectado à rede para aplicações fotovoltáica  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Este artigo descreve a modelagem e o controle de um conversor trifásico conectado à rede alimentado por um conjunto fotovoltaico. O conversor é composto de um estágio CC-CC isolado um estágio CC-CA. São obtidas funções de transferência com as quais são projetados três sistemas de controle em malha f [...] echada: um para a tensão de entrada do arranjo de painéis solares, um para a tensão do do barramento de tensão contínua e outro para as correntes trifásicas de saída. Abstract in english This paper describes the modeling and control of a three-phase grid-connected converter fed by a photovoltaic array. The converter is composed of an isolated DC-DC converter and a three-phase DC-AC voltage source inverter The converters are modeled in order to obtain small-signal transfer functions [...] that are used in the design of three closed-loop controllers: for the output voltage of the PV array, the DC link voltage and the output currents. Simulated and experimental results are presented.

Villalva, Marcelo Gradella; Espindola, Marcos Fernando; Siqueira, Thais Gama de; Ruppert, Ernesto.

368

A new method for the experimental determination of three-phase relative permeabilities  

International Nuclear Information System (INIS)

Petroleum reservoirs under primary, secondary or tertiary recovery processes usually experience simultaneous flow of three fluids phases (oil, water and gas). Reports on some mathematical models for calculating three-phase relative permeability are available in the Literature. Nevertheless, many of these models were designed based on certain experimental conditions and reservoir rocks and fluids. Therefore, special care has to be taken when applying them to specific reservoirs. At the laboratory level, three-phase relative permeability can be calculated using experimental unsteady-state or steady state methodologies. This paper proposes an unsteady-state methodology to evaluate three-phase relative permeability using the equipment available at the petrophysical analysis Laboratory of the Instituto Colombiano del Petroleo (ICP) of Ecopetrol S.A. Improvements to the equipment were effected in order to achieve accuracy in the unsteady-state measurement of three-phase relative permeability. The target of improvements was directed toward to the attainment of two objectives:1) the modification of the equipment to obtain more reliable experimental data and 2) the appropriate interpretation of the data obtained. Special attention was given to the differential pressure and uncertainty measurement in the determination of fluid saturation in the rock samples. Three experiments for three-phase relative permeability were conducted using a sample A and reservoir rock from the Colombian Foothills. Fluid tests included the utilization of synthetic brine, mineral oil, reservoir crude oil and nitrogen. Two runs were conducted at the laboratory conditions while one run was conducted at reservoir conditions. Experimental results of these tests were compared using 16 mathematical models of three-phase relative permeability. For the three-phase relative permeability to oil, the best correlations between experimental data and tests using Blunt, Hustad Hasen, and Baker's models were obtained at oil saturations between 40% and 70%

2008-01-01

369

Carrier-based PWM strategies for the comprehensive capacitor voltage balance of multilevel multileg diode-clamped converters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents four carrier-based PWM strategies for diode-clamped converters of any number of levels and any number of legs (phases). These carrier-based PWM strategies guarantee the dc-link capacitor voltage balance in every switching cycle without the need of additional hardware and with low dc-link capacitance values for any modulation index and load, provided that the sum of leg currents equals zero. The performance of the presented carrier-based PWM strategies,...

Busquets Monge, Sergio; Ruderman, Alex

2010-01-01

370

A Fully Equivalent Global Pressure Formulation for Three-Phase Compressible Flow  

CERN Multimedia

We introduce a new global pressure formulation for immiscible three-phase compressible flows in porous media which is fully equivalent to the original equations, unlike the one introduced in \\cite{CJ86}. In this formulation, the total volumetric flow of the three fluids and the global pressure follow a classical Darcy law, which simplifies the resolution of the pressure equation. However, this global pressure formulation exists only for Total Differential (TD) three-phase data, which depend only on two functions of saturations and global pressure: the global capillary pressure and the global mobility. Hence we introduce a class of interpolation which constructs such TD-three-phase data from any set of three two-phase data (for each pair of fluids) which satisfy a TD-compatibility condition.

Chavent, Guy

2009-01-01

371

A Novel Three-phase Rectifier Based on Improved PID Control Algorithm  

Directory of Open Access Journals (Sweden)

Full Text Available The three-phase rectifier based on traditional PID control algorithm can improve its harmonic effect, and increase its power factor, but it can’t overcome the problems of selection difficulty of the PID parameters and can realize the online self-turning function of the PID parameters. In order to deal with the questions, the three phase rectifier based on neural network PID control algorithm is designed in this paper. In this paper, the PID parameters of the novel rectifier can realize the function of the online self-turning, which increases the design efficiency and the control accuracy. The simulation results show that the three phase rectifier based on improved PID control algorithm can decrease the harmonic pollution and increase its power factor.

Zhang Kai

2013-01-01

372

Three-phase Single Switch Power Factor Correction Circuit with Harmonic Reduction  

Directory of Open Access Journals (Sweden)

Full Text Available A harmonic injection technique, which reduces the line frequency harmonics of the single switch three-phase boost rectifier, has been implemented. In this method, a periodic voltage is injected in the control circuit to vary the duty cycle of the rectifier switch within a line cycle so that the fifth-order harmonic of the input current is reduced to meet the total harmonic distortion (THD requirement. Since the injected voltage signal, which is proportional to the inverted ac component of the rectified three-phase line-to-line input voltages is employed; the injected duty cycle variations are naturally synchronized with the three-phase line-to-neutral input voltages.

S.M. Bashi

2005-01-01

373

A Novel Unit Power Factor Rectifier Based on Three-phase Digital PLL  

Directory of Open Access Journals (Sweden)

Full Text Available A novel three-phase phase-locked loop solution is proposed based on D-Q transformation aiming at the AC-DC rectifier with high efficiency and high power factor. The phase-locked loop is implemented digitally using the Xilinx blockset integrated with Matlab/Simulink. The three-phase digital phase-locked loop (TDPLL is elaborately designed with the parameters defined in detail. The AC-DC converter (rectifier model with the TDPLL is built and simulated in the high-speed VHS-ADC simulation platform from Canada. The simulation and test results show the TDPLL is locked right after the different three-phase voltage disturbances and very suitable for control of the rectifier with high parallelism through space vector pulse width modulation (SVPWM.  

Xuegui Zhu

2013-07-01

374

Performance Evaluation and Slip Regulation Control of an Asymmetrical Parameter Type Two-Phase Induction Motor Drive Using a Three-Leg Voltage Source Inverter  

Science.gov (United States)

This paper presents a performance evaluation and a simple speed control method of an asymmetrical parameter type two-phase induction motor drive using a three-leg VSI (Voltage Source Inverter). The two-phase induction motor is adapted from an existing single-phase induction motor resulting in impedance unbalance between main and auxiliary windings. The unbalanced two-phase inverter outputs with orthogonal displacement based on a SPWM (Sinusoidal Pulse Width Modulation) method are controlled with appropriate amplitudes for improving the motor performance. Dynamic simulation of the proposed drive system is given. A simple speed controller based on a slip regulation method is designed. The overall system is implemented on a DSP (Digital Signal Processor) board. The validity of the proposed system is verified by simulation and experimental results.

Piyarat, Wekin; Kinnares, Vijit

375

DC-bus voltage control of grid-connected voltage source converter by using space vector modulated direct power control under unbalanced network conditions  

DEFF Research Database (Denmark)

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 is introduced in the controller, which is necessary in order to reduce the dc-bus voltage ripple and active power harmonics at the same time. The proposed control topology is implemented in the lab. Simulation and experimental results are provided to validate its performance and the analysis presented in this study.

Xiao, Lei; Huang, Shoudao

2013-01-01

376

Imaging phase holdup distribution of three phase flow systems using dual source gamma ray tomography  

International Nuclear Information System (INIS)

Full text: Multiphase reaction and process systems are used in abundance in the chemical and biochemical industry. Tomography has been successfully employed to visualize the hydrodynamics of multiphase systems. Most of the tomography methods (gamma ray, x-ray and electrical capacitance and resistance) have been successfully implemented for two phase dynamic systems. However, a significant number of chemical and biochemical systems consists of dynamic three phases. Research effort directed towards the development of tomography techniques to image such dynamic system has met with partial successes for specific systems with applicability to limited operating conditions. A dual source tomography scanner has been developed that uses the 661 keV and 1332 keV photo peaks from the 137Cs and 60Co for imaging three phase systems. A new approach has been developed and applied that uses the polyenergetic Alternating Minimization (A-M) algorithm, developed by O'Sullivan and Benac (2007), for imaging the holdup distribution in three phases' dynamic systems. The new approach avoids the traditional post image processing approach used to determine the holdup distribution where the attenuation images of the mixed flow obtained from gamma ray photons of two different energies are used to determine the holdup of three phases. In this approach the holdup images are directly reconstructed from the gamma ray transmission data. The dual source gamma ray tomography scanner and the algorithm were validated using a three phase phantom. Based in the validation, three phase holdup studies we carried out in slurry bubble column containing gas liquid and solid phases in a dynamic state using the dual energy gamma ray tomography. The key results of the holdup distribution studies in the slurry bubble column along with the validation of the dual source gamma ray tomography system would be presented and discussed

2008-06-01

377

Selection of a conventional power distribution transformer as a voltage source for saline chambers; Seleccion de un transformador de distribucion convencional como fuente de voltaje en camaras salinas  

Energy Technology Data Exchange (ETDEWEB)

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.

Garza Macias, Anibal [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1988-12-31

378

A Novel Three-phase Rectifier Based on Improved PID Control Algorithm  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The three-phase rectifier based on traditional PID control algorithm can improve its harmonic effect, and increase its power factor, but it can’t overcome the problems of selection difficulty of the PID parameters and can realize the online self-turning function of the PID parameters. In order to deal with the questions, the three phase rectifier based on neural network PID control algorithm is designed in this paper. In this paper, the PID parameters of the novel rectifier can realize t...

2013-01-01

379

Area Based Approach for Three Phase Power Quality Assessment in Clarke Plane  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents an area-based approach for electric power quality analysis. Some specific reference signals have been defined and areas formed by the real power system data with the reference signal have been calculated wherefrom contributions of fundamental waveform and harmonic components have been assessed separately. Active power, reactive power and total harmonic distortion factors have been measured. Clarke transformation technique has been used for analysis in three-phase system, which has reduced the computational effort to a great extent. Distortion factors of individual phase of a three-phase system have also been assessed.

S. CHATTOPADHYAY

2008-03-01

380

Three-Phase Modulated Pole Machine Topologies Utilizing Mutual Flux Paths  

DEFF Research Database (Denmark)

This paper discusses three-phase topologies for modulated pole machines (MPMs). The authors introduce a new threephase topology, which takes advantage of mutual flux paths; this is analyzed using 3-D finite-element methods and compared to a three-phase topology using three single-phase units stacked axially. The results show that the new â??combined-phase MPMâ? exhibits a greater torque density, while offering a reduction in the number of components. The results obtained from two prototypes are also presented to verify the concept; the results show that the â??combined-phaseâ? machine could provide both performance and constructional benefits over prior MPM topologies.

Washington, Jamie G.; Atkinson, Glynn J.

2012-01-01

 
 
 
 
381

Attractor comparison analysis for characterizing vertical upward oil—gas—water three-phase flow  

Science.gov (United States)

We investigate the dynamic characteristics of oil—gas—water three-phase flow in terms of chaotic attractor comparison. In particular, we extract a statistic to characterize the dynamical difference in attractor probability distribution. We first take time series from Logistic chaotic system with different parameters as examples to demonstrate the effectiveness of the method. Then we use this method to investigate the experimental signals from oil—gas—water three-phase flow. The results indicate that the extracted statistic is very sensitive to the change of flow parameters and can gain a quantitatively insight into the dynamic characteristics of different flow patterns.

Zhao, Jun-Ying; Jin, Ning-De; Gao, Zhong-Ke; Du, Meng; Wang, Zhen-Ya

2014-03-01

382

THRIVE : a data reduction program for three-phase PDV/PDI and VISAR measurements.  

Energy Technology Data Exchange (ETDEWEB)

THRIVE (THRee Interferometer VElocimetry) is an analysis package for reducing three-phase interferometry measurements. Three-phase displacement interferometry measurements are the primary application of this program, although velocity interferometry is also supported. THRIVE uses a push-pull approach to transform measured signals to a pair of quadrature signals, from which fringe shift, target position, and target velocity are inferred. The program can analyze the signals in an ideal sense or compensate for non-ideal measurement conditions using ellipse characterization. The program can be run in any current version of MATLAB (release 2007a or later) or as a Windows XP executable.

Jones, Scott Christopher; Dolan, Daniel H.

2008-06-01

383

Asymmetrical Six-Phase Space Vector Pwm Scheme  

Directory of Open Access Journals (Sweden)

Full Text Available Multiphase electric motors have smaller torque pulsations and are more reliable that their three-phase alternatives. However, standard electricity grids around the world are three-phase, so power inverter is needed to drive multiphase motors. Inverter is used not only to power the motor, but also to control the am­plitude and frequency of the produced voltage, thus controlling motor speed and torque. Multiphase systems with odd number of phases have been widely investigated; therefore, this paper focuses on a six-phase inverter with a single neutral symmetrical load. A novel asymmetrical space vector modulation scheme is proposed and evaluated using simulations in Matlab/Simulink. Simulation results are compared to other modulation schemes. The proposed method is suitable for generating near-sinusoidal output voltages; however, it might not be suited for driving motors with sinusoidally distributed stator windings.

Tadas Lipinskis

2014-05-01

384

A Three-Phase Combined Analysis of the Sudbury Neutrino Observatory  

Energy Technology Data Exchange (ETDEWEB)

The presented analysis from the Sudbury Neutrino Observatory (SNO) will combine the photomultiplier tube data from the three phases along with the results from a pulse shape analysis of the data from the Neutral Current Detection (NCD) array used during the third phase to provide the most accurate {sup 8}B and hep SNO measurements.

Drouin, P.-L. [Carleton University, Ottawa (Canada); Howard, C. [University of Alberta (Canada); Barros, N.

2012-08-15

385

Five-Level Cascade Multilevel Inverter Three-Phase Motor Drive Using a Single DC Source.  

Science.gov (United States)

A method is presented showing that a 5-level cascade multilevel inverter for a three-phase permanent magnet sychronous motor drive can be implemented using only a single DC link to supply a standard 3-leg inverter along with three full H-bridges supplied ...

J. N. Chiasson

2006-01-01

386

The analysis of magnesium oxide hydration in three-phase reaction system  

Science.gov (United States)

In order to investigate the magnesium oxide hydration process in gas-liquid-solid (three-phase) reaction system, magnesium hydroxide was prepared by magnesium oxide hydration in liquid-solid (two-phase) and three-phase reaction systems. A semi-empirical model and the classical shrinking core model were used to fit the experimental data. The fitting result shows that both models describe well the hydration process of three-phase system, while only the semi-empirical model right for the hydration process of two-phase system. The characterization of the hydration product using X-Ray diffraction (XRD) and scanning electron microscope (SEM) was performed. The XRD and SEM show hydration process in the two-phase system follows common dissolution/precipitation mechanism. While in the three-phase system, the hydration process undergo MgO dissolution, Mg(OH)2 precipitation, Mg(OH)2 peeling off from MgO particle and leaving behind fresh MgO surface.

Tang, Xiaojia; Guo, Lin; Chen, Chen; Liu, Quan; Li, Tie; Zhu, Yimin

2014-05-01

387

Shielding effect of non-ferrous metallic plates in vicinity of three phase conductors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper uses multi conductor based method (MCM) for numerical estimation of magnetic field cancellation around balanced three phase power conductors introduced by aluminum plates. Aluminum was identified as a suitable shielding material for moderate field reduction due to its low cost and satisfactory shielding performance.

Milutinov Miodrag; Pekari?-Na? Neda

2005-01-01

388

Shielding effect of non-ferrous metallic plates in vicinity of three phase conductors  

Directory of Open Access Journals (Sweden)

Full Text Available This paper uses multi conductor based method (MCM for numerical estimation of magnetic field cancellation around balanced three phase power conductors introduced by aluminum plates. Aluminum was identified as a suitable shielding material for moderate field reduction due to its low cost and satisfactory shielding performance.

Milutinov Miodrag

2005-01-01

389

Induction machines with two three-phase windings in convertor applications  

Energy Technology Data Exchange (ETDEWEB)

Harmonic currents and torques have been investigated with calculations and measurements on a 11 kW induction machine connected to two transistor convertors. The standard winding in the induction machine has been replaced with a new winding, consisting of two three-phase windings separated 30 electrical degrees. The results from the investigation show that harmonic torques can be reduced. (orig).

Hylander, J.; von Zweygbergk, S. (Chalmers Univ. of Tech., Goeteborg (Sweden). Dept. of Electical Machines and Power Electronics)

1989-01-01

390

Three-phase diode rectifiers with low harmonics current injection methods  

CERN Multimedia

Presents results of numerous research papers in the area of current injection based rectifiers. This book discusses the principles of current injection, followed by an analysis of various magnetic current injection devices. It concludes with a chapter where the results are generalized to three-phase full-bridge thyristor rectifiers.

Pejovic, Predrag

2007-01-01

391

Speed Control of a Three Phase Alternating Current Induction Motor Using Space Vector Pulse Width Modulation  

Directory of Open Access Journals (Sweden)

Full Text Available Sinusoidal pulse width modulation is a popular modulation for most alternating current induction motor. It only requires fewer calculations and is easy to implement. However, the shortcomings of using it are low DC voltage utilization, and poor inverter transmission capability. In recent years, there is an increasing trend and more research concentration of using space vector pulse width modulation in adjustable speed drives and renewable energy systems because it has better DC bus utilization, better performance, lower loss, lower ripples, and wide application range. This paper introduces space vector pulse width modulation and applies to speed control of alternating current induction motor. The three phase alternating current induction motor is reviewed based upon space vector representation. The development of space vector pulse width modulation and implementation to speed control of induction motor is done using Matlab/Simulink. The simulation is conducted by analyzing the response of stator current, stator voltage, speed, voltage, frequency, and the electromagnetic torque. Simulation results shows that space vector pulse width modulation which generates the voltage patterns at real time is able to control the speed of a three phase alternating current induction motor. It indicates the validity of space vector pulse width modulation in controlling the speed of a three phase alternating current induction motor (ACIM. In conclusion, the use and realization of space vector pulse width modulation has been validated by the Matlab/Simulink simulation experiment for controlling the speed of a three phase alternating current induction motor.

Angelo A. Beltran Jr

2014-04-01

392

An unsteady-state technique for three-phase relative permeability measurements  

Energy Technology Data Exchange (ETDEWEB)

In situ recovery of heavy oils and bitumens often involves simultaneous flow of oil, water and gas in the oil sands. Such multi-phase flow in porous media is a complex process. Mathematical simulation of such recovery processes requires a knowledge of three-phase relative permeability characteristics of the system. Experimentally measured three-phase relative permeability data for heavy oil reservoirs are not available in the literature. This lack of data is primarily due to the tedious nature of such measurements and shows a need for developing less time consuming methods. An unsteady-state technique similar to the Johnson-Bossler-Naumann (JBN) method for two-phase flow was developed and used to estimate three-phase relative permeability data. The method was validated by comparing the oil isoperms with those obtained using the steady-state method. A reasonably good agreement was obtained which suggests that the proposed unsteady-state method could be employed as a faster alternative to obtain three-phase relative permeability data. 21 refs., 7 figs., 2 tabs.

Sarma, H.K.; Maini, B.B. (Petroleum Recovery Inst., Calgary, AB (Canada)); Jha, K.N. (Canada Centre for Mineral and Energy Technology, Ottawa, ON (Canada))

1994-02-01

393

Teaching Qualitative Research for Human Services Students: A Three-Phase Model  

Science.gov (United States)

Qualitative research is an inherent part of the human services profession, since it emphasizes the great and multifaceted complexity characterizing human experience and the sociocultural context in which humans act. In the department of human services at Emek Yezreel College, Israel, we have developed a three-phase model to ensure a relatively…

Goussinsky, Ruhama; Reshef, Arie; Yanay-Ventura, Galit; Yassour-Borochowitz, Dalit

2011-01-01

394

Three-phase scintigraphy in epicondylitis of the lateral lower humerus  

Energy Technology Data Exchange (ETDEWEB)

Ten patients with tennis elbow were examined by three-phase scintigraphy, using sup(99m)Tc-MDP. In agreement with the histological findings of H. Schneider (14), there was no uptake during the perfusion and soft tissue phase. In the phase, there was focal bone uptake in one patient only.

Koppers, B.; Riel, K.

1982-08-01

395

A Phase-Field Model Based on a Three-Phase-Lag Heat Conduction  

International Nuclear Information System (INIS)

Our aim in this article is to study a phase-field system based on a three-phase-lag for the thermal flux vector. In particular, we prove the existence and uniqueness of solutions and then study the spatial behavior of the solutions in a semi-infinite cylinder, when such solutions exist.

2011-02-01

396

A voltage control strategy for current-regulated PWM inverters  

Energy Technology Data Exchange (ETDEWEB)

Alternative voltage control strategies for current-regulated PWM inverters are analyzed, including previously established feedforward and feedforward/feedback controllers and a newly proposed decoupling feedback control strategy. The steady-state and dynamic characteristics of each of these control methods are illustrated and compared for a selected inverter design. It is shown that the feedforward controller exhibits steady-state error and an undesirable overshoot of the output voltages during startup. The addition of a feedback loop eliminates the steady-state error and reduces the overshoot; however, the natural response is underdamped regardless of the choice of feedback gains. A decoupling feedback control strategy that eliminates the disadvantages of the feedforward and feedforward/feedback controllers is described. Using the decoupling feedback controller, it is possible to eliminate the steady-state error and place the closed-loop poles wherever desired. Moreover, if the closed-loop poles are selected appropriately, it is possible to eliminate the overshoot of the output voltages during startup transients.

Wasynczuk, O.; Sudhoff, S.D.; Tran, T.D. [Purdue Univ., West Lafayette, IN (United States). School of Electrical Engineering; Clayton, D.H.; Hegner, H.J. [Naval Surface Warfare Center, Annapolis, MD (United States). Carderock Div.

1996-01-01

397

Controlador repetitivo para inversores PWM com referência de freqüência variável  

Directory of Open Access Journals (Sweden)

Full Text Available Controladores repetitivos têm se mostrado eficazes na rejeição de distúrbios cíclicos em inversores de tensão modulados por largura de pulso. Contudo, observa-se que estes controladores têm seu desempenho comprometido caso seu período não seja sincronizado com o período do sinal de referência, o que restringe o seu uso em aplicações de freqüência variável. Para mitigar este problema, é proposta uma modificação nestes controladores para adequá-los à aplicações com referência senoidal de freqüência variável. O algoritmo proposto é simples, sendo apenas ajustados o comprimento das memórias circulares e os ponteiros empregados para endereçá-las nos controladores repetitivos convencionais. Resultados experimentais, obtidos em dois protótipos com especifiações distintas, são apresentados para validar a técnica proposta.Repetitive controllers have demonstrated efficacy in the rejection of cyclic disturbances in pulse-width modulated voltage-source inverters. However, the performance of these controllers is compromised if their period are not synchronized with the period of the reference signal. This drawback restrict their use in variable frequency applications. In order to mitigate this problem, it is proposed a modification in these controllers to make them suitable for sinusoidal references with variable frequency. The proposed algorithm is simple given that is only performed a chance in the length of circular buffers and in the pointer used to address them. Experimental results, obtained with two different prototypes, are presented to validate the proposed technique.

Leandro Michels

2009-09-01

398

The fuel properties of three-phase emulsions as an alternative fuel for diesel engines  

Energy Technology Data Exchange (ETDEWEB)

The pollutants emitted from diesel engines (in particular nitrogen oxides and particulate matter) are detrimental to the health of living beings and ecological environment have been recognized as the major air pollution source in metropolitan areas and have thus attracted much research interest. Although diesel oil emulsion has been considered as a possible approach to reduce diesel engine pollutants, previous relevant applications were restricted to two-phase emulsions. Three-phase emulsions such as oil-in-water-in-oil briefly denoted as O/W/O emulsions and water-in-oil-in-water, denoted as W/O/W, have not been used as an alternative fuel for any combustion equipment. Studies on the properties of three-phase emulsion as fuel have not been found in the literature. The emulsification properties of an O/W/O three-phase diesel fuel emulsion were investigated in this experimental study. The results show that the mean drop size of the O/W/O emulsion was reduced significantly with increasing homogenizing machine revolution speed. An increase in inner phase proportion of the O/W/O emulsion resulted in increasing the emulsion viscosity. The viscosity of O/W/O emulsion is greater than that for water-in-oil (denoted briefly as W/O emulsion) for the same water content. More stable emulsion turbidity appeared for three-phase O/W/O diesel emulsions added with emulsifier with HLB values ranging from 6 to 8. In addition, three-phase O/W/O emulsions with greater water content will form a larger number of liquid droplets, leading to a faster formation rate and greater emulsion turbidity at the beginning but a faster descending rate of emulsion turbidity afterwards. The potential for using O/W/O emulsions as an alternative fuel for diesel engines was also evaluated. 15 refs., 11 figs., 7 tabs.

Cherng-Yuan Lin; Kuo-Hua Wang [National Taiwan Ocean University, Keelung (Taiwan). Department of Marine Engineering

2003-07-01

399

CFD modeling of three-phase bubble column: 1. Study of flow pattern  

Energy Technology Data Exchange (ETDEWEB)

Bubble column (BC) or slurry bubble column (SBC) reactor has emerged as one of the most promising devices in chemical, biochemical and environmental engineering operations because of its simple construction, isothermal conditions, high heat and mass transfer rates, and on-line catalyst addition and withdrawal. Applications include absorption, catalytic slurry reactions, bioreactions and coal liquefaction. The present work has been carried out to characterize the dynamics of three-phase flow in cylindrical bubble column, run under homogeneous bubble flow and heterogeneous flow conditions using CFD (Computational Fluid Dynamics) simulation. The investigation has been done to study the flow pattern of three-phase bubble column along with parametric studies. The simulations were performed for air-water-glass beads in a bubble column of 0.6m height, 0.1m i.d. and 0.05m sparger diameter to study the flow pattern. Eulerian-Eulerian three-phase simulations with {kappa}-{epsilon} turbulence for liquid phase were carried out using the commercial flow simulation software CFX-5.6, with a focus on characterizing the dynamics properties of gas liquid solid flows. The model has been validated using available experimental data and is in good agreement. Detail study of the flow pattern in three-phase bubble column has been carried out and flow pattern has been presented in the form of contour and vector plots. The results presented are useful for understanding the dynamics of gas liquid solid flows in bubble column and provide a basis for further development of CFD model for three phase systems.

M. Anil; V.K. Agarwal; M. Siraj Alam [Indian Institute of Technology, Roorkee (India). Chemical Engineering Department; K.L. Wasewar [Indian Institute of Technology, Roorkee (India). Chemical Engineering Department]. k_wasewar@rediffmail.com

2007-09-15

400

The method for simultaneous extraction and back extraction in liquid three-phase system and equipment for simultaneous extraction and back extraction in liquid three-phase system  

International Nuclear Information System (INIS)

The method for simultaneous extraction and back extraction in liquid three-phase system has been worked out. The equipment designed for that process has been also subject of the patent. The interesting component is extracted first to intermediate phase consists of magnetic solvent keeping two extracting phases separately. The intermediate magnetic liquid has been kept in its position using a stable magnet maintained on the surface of the extraction vessel. Then the component pass from intermediate phase to the third phase as a result of back extraction. Mixing in the extraction and back extraction zones is organized by means of rotating shaft going along the whole apparatus. The extraction and back extraction processes occur simultaneously as a result of continuous flow of solvent in their zones. The single extraction back extraction facilities can be joined in larger batteries. 3 figs

1988-11-02

 
 
 
 
401

Isolated PDM and PWM DC-AC SICAMs[Pulse Density Modulated; Pulse Width Modulated  

Energy Technology Data Exchange (ETDEWEB)

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)

Ljusev, P.

2004-03-15

402

Area Equalization PWM Techniques for Single-Phase Full Bridge Inverter with Fluctuating DC Input  

Directory of Open Access Journals (Sweden)

Full Text Available An extension of equal sampling technique (EST based pulse width modulation (PWM is presented for the single-phase inverter to reduce lower order harmonics caused by the fluctuating dc input. In the EST, which has been proposed earlier for constant dc, the width of PWM pulses is determined by making the area of the PWM signal equal to the area under the sampled reference waveform. The concept of equal area criterion equally applicable for fluctuating dc input with required modifications of the governing equations. Simulation results show that EST is triumphant in reducing lower order harmonics. Potential applications of the proposed technique are in fixed and variable frequency inverters for power supplies and ac motor drives which experience voltage ripple in the dc-link either when fed from a weak ac system or when insufficient filtering is employed.

G Pavankumar

2007-01-01

403

A deadbeat control method for a PWM converter applied to a superconducting magnet  

International Nuclear Information System (INIS)

Current-type pulse-width-modulated (PWM) converter is regarded as one of the candidates for the superconducting magnet power supplies in next generation tokamak devices. However, this type PWM converter has a problem of the transient oscillation of the reactor current and capacitor voltage in an AC-side harmonic filter, which occurs owing to the LC resonance of the filter when the reference of the DC output current is changed rapidly. In this paper, the new PWM control method based on the deadbeat control theory is proposed to suppress the transient oscillation. The converter employing this method can control the reactor current and capacitor voltage in one sampling period under ideal conditions. In addition, the effect of dead time on the control is discussed. The performance of the newly proposed method is demonstrated through numerical circuit simulation

2001-11-01

404

Fracture healing: Quantitative three-phase bone scintigraphy as a prognostic factor  

International Nuclear Information System (INIS)

Aim: Careful clinical examination and conventional radiography, together with other standard methods for evaluation of bone fracture healing, are frequently inconclusive. Furthermore, it is difficult to predict the complications of healing on the basis of clinical and radiographic findings only. Bone scintigraphy plays an important role in detecting bone fractures. This method is very sensitive, but not enough specific. The aim of this work was to evaluate the role of three-phase bone scintigraphy in the healing prognosis of long bone fractures. Material and Methods: We evaluated the three elements (perfusion, blood pool and static image) of three-phase bone scintigraphy in early prognosis of the course of fracture healing in patients with fractures of femur or tibia. Three-phase bone scintigraphy was performed in 73 patients. The patients were divided into 4 groups according to X-ray and clinical examination: 1) Non operated patients with stable fracture, 2) Operated patients with unstable fracture (infection), 3) Fractures with delayed union, 4) Patients with pseudoarthrosis. Using region of interest (ROI) method we compared the activity on the site of fracture with the activity on the symmetrical place in the healthy bone. The relative indices for each group of patients and for each element of three-bone scintigraphy were calculated in order to make possible the follow up of the fracture healing and to obtain data for prognosis and evaluation of possible complications. Results: The most valuable results were obtained by quantitative analysis of perfusion data immediately after trauma and 2-3 weeks later. Our results show a high diagnostic accuracy in identifying infection by perfusion scintigrams immediately after trauma. The perfusion indices obtained immediately and after 2-3 weeks could predict delayed union after the trauma. Quantitative analysis of blood pool phase gave no data of clinical significance in distinguishing various pathologies. Conclusion: Our results indicate that the three-phase bone scintigraphy is a useful method when complications of fracture healing are expected. In these cases radiography gives only a partial insight into the state of bone union, but no information about the healing process. So, the increasing use of three-phase bone scintigraphy is quite understandable. Nevertheless, as most of the fractures heal regularly, we would not advise the three-phase bone scintigraphy as a routine procedure

2002-09-01

405

Synthesis of PWM and quasi-resonant DC-to-DC power converters  

Energy Technology Data Exchange (ETDEWEB)

Synthesis procedures for systematic construction of switched-mode DC-to-DC converter topologies in the two largest families-PWM (square-wave) and Quasi-Resonant (QR) - are developed in this thesis. The proposed synthesis procedure for PWM converter is based on a matrix representation of the converter topology and on general properties of PWM networks. The properties derived in the thesis include a constraint on the number of switches, a constraint on the number of reactances, and relations between the network complexity and attainable DC conversion ratios. The synthesis procedure starts with a set of desired specifications, which may include the DC conversion ratio, features of non-pulsating terminal currents and possible coupling of inductors, the number of reactances, the number of switches and, in particular, the number of active, transistor switches. Outputs of the procedure are all possible PWM converters that satisfy the required specifications. Quasi-Resonant converters - a family of DC-to-DC converters featuring zero-voltage or zero-current switching - are derived by adding two or more resonant elements to a two-switch PWM converter. Systematic synthesis of QR converters is based on extraction of all topologically distinct positions of resonant elements within a PWM converter. Addition of two resonant elements yields six classes of QR converters, two of which have not been identified before. Subject to different switch realizations and control timing, QR converters can exhibit vastly different behavior and properties. In particular, it is shown that a controllable rectifier can be used to achieve constant-frequency control in all QR converters. Unified DC analyses are completed for QR classes and operating modes of most practical interest.

Maksimovic, D.

1989-01-01

406

Half bridge ZVS DC-DC converter with DCS PWM active clamp technique  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Half bridge (HB) dc–dc converter is an attractive topology for middle power level applications owing to its simplicity. This paper presents 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 one of the two switches without adding extra components and without adding asymmetric penalties of the complementary control. The concept of this new control scheme is shifting one o...

JANAPATI SIVAVARA PRASAD

2012-01-01

407

Led spectral and power characteristics under hybrid PWM/AM dimming strategy  

DEFF Research Database (Denmark)

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.

Beczkowski, Szymon; Munk-Nielsen, Stig

2010-01-01

408

Synchronized PWM Scheme for Dual Inverter-Fed Drives with Zero Common-Mode Voltages  

DEFF Research Database (Denmark)

Abstract - Novel method of direct synchronized pulsewidth modulation is applied for control of a dual inverter-fed opened winding induction motor drive with zero common-mode voltages. New strategy and algorithms of synchronized PWM provide symmetry of the phase voltage of the system during the whole control range including the zone of overmodulation. Spectra of the phase voltage do not contain even harmonics and sub-harmonics (combined harmonics), which is especially important for the drive systems with increased power rating. Simulations gave the behaviour of dual inverter-fed system with the proposed synchronized PWM scheme.

Oleschuk, Valentin; Blaabjerg, Frede

2005-01-01

409

Modeling and identification of a solenoid valve for PWM control applications  

Science.gov (United States)

In this Note, a nonlinear dynamic model of a PWM-driven pneumatic fast switching valve is presented. The electro-magnetic, mechanical and fluid subsystems of the valve are investigated, including their interactions. Unknown parameters are identified using direct search optimization and model validation is performed by comparing the simulated and measured current curves. In order to use this model in PWM control applications, a simplification strategy is also proposed and a static model is obtained between the duty cycle input and the moving average of the spool position. The simplified static model is validated again by experiments. To cite this article: M. Taghizadeh et al., C. R. Mecanique 337 (2009).

Taghizadeh, M.; Ghaffari, A.; Najafi, F.

2009-03-01

410

Identifying three-phase induction motor faults using artificial neural networks  

Science.gov (United States)

This paper presents an artificial neural network (ANN) based technique to identify faults in a three-phase induction motor. The main types of faults considered are overload, single phasing, unbalanced supply voltage, locked rotor, ground fault, over-voltage and under-voltage. Three-phase currents and voltages from the induction motor are used in the proposed approach. A feedforward layered neural network structure is used. The network is trained using the backpropagation algorithm. The trained network is tested with simulated fault current and voltage data. Fault detection is attempted in the no fault to fault transition period. Off-line testing results on a 3 HP induction motor model show that the proposed ANN based method is effective in identifying various types of faults. PMID:11106295

Kolla; Varatharasa

2000-01-01

411

Analysis of three-phase power-supply systems using computer-aided design programs  

International Nuclear Information System (INIS)

A major concern of every designer of large, three-phase power-supply systems is the protection of system components from overvoltage transients. At present, three computer-aided circuit design programs are available in the Magnetic Fusion Energy (MFE) National Computer Center that can be used to analyze three-phase power systems: MINI SCEPTRE, SPICE I, and SPICE II. These programs have been used at Lawrence Livermore Laboratory (LLL) to analyze the operation of a 200-kV dc, 20-A acceleration power supply for the High Voltage Test Stand. Various overvoltage conditions are simulated and the effectiveness of system protective devices is observed. The simulated overvoltage conditions include such things as circuit breaker openings, pulsed loading, and commutation voltage surges in the rectifiers. These examples are used to illustrate the use of the computer-aided, circuit-design programs discussed in this paper

1977-10-29

412

Existence of three-phase interlines on a cerium dioxide surface  

CERN Document Server

The three-phase interline described by a statistical continuum limit (i.e. quasi-boundary) has been postulated to gain a deeper insight into the reduction of CeO2 to CeO1.940 in a LiCl-KCl eutectic melt. Fabrication of a CeO2 superstructure by a condensed-phase method provided a CeO2 (111) surface at the nanoscale, which allowed the three-phase interline to be identified given previously reported quantum confinement effects in quasi-stoichiometric CeO2 nanoparticles. Also, the CeO2 superstructure displays the same crystal lattice planes as a bulk CeO2 grain but the triply degenerate Raman-active peak of the grain is higher by a factor of ~ 2.5 with a wider full width at half maximum.

Osarinmwian, Charles

2013-01-01

413

Simulation study of three-phase induction motor with variations in moment of inertia  

Directory of Open Access Journals (Sweden)

Full Text Available Transient performance of any electrical machine is greatly affected by sudden changes in its supply system, operating speed, shaft load including any variations in moment of inertia due to gear arrangement applications. D, q- axis modeling which is universally acceptable to determine such analysis may be adopted using stator reference frame/rotor reference frame/synchronously rotating reference frame. In this paper, rotor reference frame is used for the simulation study of three phase induction motor. MATLAB/SIMULINK based modeling is adopted to compare the transient performance of three-phase induction motor including main flux saturation with and without the moment of inertia (MOI of the system attached to the motor. Simulated results have been compared and verified with experimental results on a test machine set-up. A close agreement between the simulated and experimental results proves the validity of proposed modeling.

K. S. Sandhu

2009-08-01

414

A three-phase optimization method for reload core design in PWRs(II)  

International Nuclear Information System (INIS)

A three-phase optimization method for determining an optimal loading pattern for pressurized water reactors has been developed. This method is composed of three phases. In the first phase, only the fast group diffusion equation is solved to get an ideal fuel region. In the second phase, using the result of the first phase, a heuristic algorithm, what is called the even-odd rule, is newly introduced to obtain the optimal fuel assembly distribution which has maximum soluble boron concentration at the EOC. Finally, a suitable control poison distribution which maintains an optimal power shape throughout the cycle is determined. To validate the feasibility of the method, it is applied to the cycle 4 of Kori Unit 4. The critical soluble boron concentration of the optimal loading pattern at the EOC is about 20 ppm higher than that of the standard loading pattern

1991-05-24

415

Axial dispersion of the liquid phase in a three-phase Karr reciprocating plate column  

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Full Text Available The influence of the gas flow rate and vibration intensity in the presence of the solid phase (polypropylene spheres on axial mixing of the liquid phase in a three phase (gas-liquid-solid Karr reciprocating plate column (RPC was investigated. Assuming that the dispersion model of liquid flow could be used for the real situation inside the column, the dispersion coefficient of the liquid phase was determined as a function of different operating parameters. For a two-phase liquid-solid RPC the following correlation was derived: DL = 1.26(Af1.42 UL0.51 eS0.23 and a similar equation could be applied with ± 30 % confidence for the calculation of axial dispersion in the case of a three-phase RPC: DL = 1.30(Af0.47 UL0.42 UG0.03eS-0.23.

DEJAN U. SKALA

2004-07-01

416

Three phase fault diagnosis based on RBF neural network optimized by PSO algorithm  

Directory of Open Access Journals (Sweden)

Full Text Available The present paper proposes a fault diagnosis methodology of three phase inverter circuit base on radial basis function (RBF artificial neural network trained by particle swarm optimization (PSO algorithm. Using the appropriate stimulus signal, fault features are extracted from efficient points in frequency response of the circuit directly, and then a fault dictionary is created by collecting signatures of different fault conditions. Trained by the examples contained in the fault dictionary, the RBF neural network optimized by PSO has been demonstrated to provide robust diagnosis to the difficult problem of soft faults in three phase inverter circuits. The experimental result shows that the proposed technique is succeeded in diagnosing and locating faults effectively.

M. Sivakumar

2011-12-01

417

Performance Comparison of Three-Phase Shunt Active Power Filter Algorithms  

Directory of Open Access Journals (Sweden)

Full Text Available The usage of parallel converters is ever increasing. However, the voltage and current harmonics, zero-sequence and negative- sequence components of voltage and current and reactive power present in parallel converters give an alarming signal to power system and power electronic engineers. This research discusses performance of three-phase shunt active power filter (APF system using three different control techniques namely synchronous detection algorithm (SDM, instantaneous active and reactive (p-q theory and instantaneous direct and quadrature (d-q current method for the control of zero and negative sequence components, reactive power and harmonics. The novelty of this research lies in the successful application of SDM based APF and (d-q current method APF for the control of reactive power, harmonics and negative and zero sequence currents resulted by the use of parallel three-phase converters. MATLAB 6.1 toolbox is used to model the systems.

Moleykutty George

2008-01-01

418

Transient analysis of three-phase induction machine using different reference frames  

Directory of Open Access Journals (Sweden)

Full Text Available Three-phase induction machines are generally used as motors for many industrial applications and all this is due to its simple construction and other advantages in contrast to other machines. Popularity of these motors has resulted into a lot of research including the transient behavior of the machine. Literature survey reveals that most of the researchers