Showing papers on "PWM rectifier published in 2009"
Book•
14 Dec 2009
TL;DR: In this paper, the authors present a detailed analysis of the current control of a three-phase FOUR-WIRE DISTRIBUTED GENERATION (DG) INVERTER in island mode.
Abstract: PREFACE. ACKNOWLEDGMENTS. 1 SMART GRID DISTRIBUTED GENERATION SYSTEMS. 2 INVERTER CONTROL VOLTAGE AND CURRENT IN DISTRIBUTED GENERATION SYSTEMS. 3 PARALLEL OPERATION OF INVERTERS IN DISTRIBUTED GENERATION SYSTEMS. 4 POWER CONVERTER TOPOLOGIES FOR DISTRIBUTED GENERATION SYSTEMS. 5 VOLTAGE AND CURRENT CONTROL OF A THREE-PHASE FOUR-WIRE DISTRIBUTED GENERATION (DG) INVERTER IN ISLAND MODE. 6 POWER FLOW CONTROL OF A SINGLE DISTRIBUTED GENERATION UNIT. 7 ROBUST STABILITY ANALYSIS OF VOLTAGE AND CURRENT CONTROL FOR DISTRIBUTED GENERATION SYSTEMS. 8 PWM RECTIFIER CONTROL FOR THREE-PHASE DISTRIBUTED GENERATION SYSTEM. 9 MATLAB SIMULINK SIMULATION TESTBED. APPENDIX A: SIMULINK MODEL DSIMSERVO.MDL. APPENDIX B: FILE SSMODE.M. BIBLIOGRAPHY. INDEX.
154 citations
21 Mar 2009
TL;DR: In this article, the minimum ripple energy storage requirement is derived independent of a specific topology, and the feasibility of the active capacitor's reduction schemes is verified by simulation and experimental results.
Abstract: It is well known that there exist second-order harmonic current and corresponding ripple voltage on dc bus for single phase PWM rectifiers. The low frequency harmonic current is normally filtered using a bulk capacitor in the bus which results in low power density. This paper studies the energy storage capacitor reduction methods for single phase rectifiers. The minimum ripple energy storage requirement is derived independent of a specific topology. Based on the minimum ripple energy requirement, the feasibility of the active capacitor's reduction schemes is verified. Then, we propose a bidirectional buck-boost converter as our ripple energy storage circuit that can effectively reduce the energy storage capacitance. Simulation and experimental results are provided for verification purposes.
110 citations
TL;DR: In this article, a simple single-input-single-output model is constructed by separating the d -axis and the q-axis dynamics through appropriate nonlinear feedforward decoupling while maintaining nearly unity power factor operation.
Abstract: The challenge in controlling a three-phase pulsewidth modulation (PWM) rectifier under balanced conditions arises from the fact that the state-space averaged model reported in literature has a multi-input-multi-output nonlinear structure and furthermore exhibits a nonminimum phase feature In this paper, a simple single-input-single-output model is constructed by separating the d -axis and the q-axis dynamics through appropriate nonlinear feedforward decoupling while maintaining nearly unity power factor operation With the proposed model, the nonminimum phase feature inherent in an AC-to-DC rectifier becomes a simple right-half-plane zero appearing in the small-signal control-to-output transfer function In addition, the model exhibits a close similarity to a DC-DC boost converter under both large-signal and small-signal operating conditions This makes it possible to extend the system analysis and control design techniques of DC-DC converters to the three-phase PWM rectifier also The validity of the proposed model has been verified experimentally in the frequency domain under open-loop operation of the PWM rectifier The usefulness of the model is further demonstrated through closed-loop operation of the rectifier with both voltage mode and inner-current-loop-based schemes
85 citations
TL;DR: In this article, 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.
83 citations
TL;DR: In this article, two new methods are proposed to overcome the major technical challenge with a hysteretic control and energy release circuit, and a controllable pulsewidth modulation (PWM) rectifier.
Abstract: Hybrid active power filter with injection circuit (IHAPF) shows great promise in reducing harmonics and improving power factor with a relatively low capacity active power filter, but suffers from DC-side voltage instability that inadvertently impacts the compensation performance and safety of the IHAPF. In this paper, two new methods are proposed to overcome this major technical challenge with a hysteretic control and energy release circuit, and a controllable pulsewidth modulation (PWM) rectifier. Modeling, theoretical analysis, and experimental results have verified that both methods can stabilize DC-side voltage within a certain range. A prototype IHAPF system was built incorporating the PWM rectifier DC voltage control scheme, and installed in a 220 kV substation in Southern China. It demonstrated significant improvement in harmonics reduction and power factor. The DC voltage stability issue was also resolved with the new design.
74 citations
01 Nov 2009
TL;DR: In this paper, a modified one-cycle-control (OCC) scheme is proposed for regulating three-phase PWM rectifiers operating under unbalanced and distorted supply conditions, where the concept of reconstructing the appropriate reference signals in the OCC control core is introduced, before modifications are recommended for altering the key control equation.
Abstract: In this paper, a modified one-cycle-control (OCC) scheme is proposed for regulating three-phase pulsewidth-modulated (PWM) rectifiers operating under unbalanced and distorted supply conditions. Mathematical analysis is first presented to show the dominant harmonic-voltage components appearing across the dc link of the PWM rectifier when it is controlled by an existing OCC scheme. Such dc-link harmonics when produced may aggravate harmonic currents flowing into the input terminals of the three-phase rectifier. To address these interrelated unbalance and harmonic concerns, the concept of reconstructing the appropriate reference signals in the OCC control core is introduced, before modifications are recommended for altering the key control equation. The improved OCC controller eventually developed is proven to exhibit minimal input-current distortion and a smoother dc-link voltage without using large capacitance. Other advantages exhibited by the traditional OCC scheme, such as no phase-locked loop, no frame transformation, and constant switching frequency, are also retained by the improved controller, whose theoretical findings are fully verified by experimental results obtained from a 1.2-kW three-phase PWM rectifier built in the laboratory.
51 citations
03 May 2009
TL;DR: In this paper, the authors discuss the need to detect, identify and locate the fault in a motor-drive system and how to operate under faulty conditions with the aim of improving the reliability of the system.
Abstract: Motor drives reliability is becoming a fundamental aspect of their general performance due to the widespread use of motor-drive systems in numerous critical applications. Therefore, strategies able to operate under faulty conditions are of extreme importance. However, for them to operate there is the obvious need of detecting, identifying and locating the fault.
47 citations
TL;DR: In this article, a three-phase PWM rectifier-inverter topology for UPS applications is proposed, which uses only nine IGBT devices for AC/AC conversion through a quasi d.c. link circuit.
Abstract: A novel three-phase PWM rectifier-inverter topology (Fig. 2) for UPS applications is proposed in this paper. The topology uses only nine IGBT devices for AC/AC conversion through a quasi d.c. link circuit. This converter topology features sinusoidal inputs and outputs, unity input power factor, and more importantly, low manufacturing cost. The operating principle of the converter is elaborated and a dedicated space vector modulation scheme is presented. The performance of the proposed converter is verified by experiments on a 5 kVA prototyping UPS system.
42 citations
17 May 2009
TL;DR: 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 methods are provided to prove that intelligent optimization are more effective and simple than traditional methods.
Abstract: Compared to traditional L filter, a LCL filter is more effective on reducing harmonic distortion at switch frequency. So it is important to choose the LCL filter parameters to achieve good filtering effect. This paper introduces some traditional design methods. Design of a LCL filter by genetic algorithm (GA) and particle swam optimization (PSO) are presented in this paper and comparison of the two intelligent optimization. Simulation result and calculate data are provided to prove that intelligent optimization are more effective and simple than traditional methods.
41 citations
TL;DR: A novel optimal modulation strategy whose objective is to reduce the total harmonic distortion of the input current and the results confirm the advantages of the proposed strategy, namely, less input current distortion and remarkable reduction of higher order harmonics compared with the SHE method, while keeping a low-switching behavior.
Abstract: High-power converters for regenerative drives and distributed generation need a network-friendly operation, low harmonic conductive electromagnetic emission for low electromagnetic interference and high electromagnetic compatibility reaching high reliability and performance. Nevertheless, the converters must be controlled with low switching frequency in order to reduce the commutation losses. These two requirements can be satisfied if an optimal modulation strategy is used. The selective harmonic elimination (SHE) is one of the low-switching-frequency strategies most used today. However, this strategy only eliminates a reduced set of harmonic components from the input current. This paper presents a novel optimal modulation strategy whose objective is to reduce the total harmonic distortion of the input current. Six- and twelve-pulse three-level neutral-point-clamped pulsewidth modulation rectifiers are used in order to implement both modulation techniques. The results confirm the advantages of the proposed strategy, namely, less input current distortion and remarkable reduction of higher order harmonics compared with the SHE method, while keeping a low-switching behavior.
40 citations
01 Nov 2009
TL;DR: In this paper, a hybrid offshore wind and tidal energy conversion system is proposed, where the generator is designed to achieve direct-drive application and a Permanent Magnet Synchronous Generator (PMSG) model is established in the dq-synchronous rotating frame, and Maximum Power Point Tracking (MPPT) is realized through controlling the speed of the generators using PWM controlled rectifiers.
Abstract: This paper proposes a hybrid offshore wind and tidal energy conversion system In this study, dynamic model and control schemes of this hybrid system are presented Gearless generators are designed to achieve direct-drive application A Permanent Magnet Synchronous Generator (PMSG) model is established in the dq-synchronous rotating frame, and Maximum Power Point Tracking (MPPT) is realized through controlling the speed of the generators using PWM controlled rectifiers In order to verify the presented control strategy and to study the interaction between wind and tidal energy conversion systems, MATLAB/Simulink® simulations have been conducted The results prove the potential feasibility of the proposed system topology
01 Jan 2009
TL;DR: In this article, a distributed generation based on stand-alone wind energy conversion system (WECS) using a variable speed permanent magnet synchronous generator (PMSG) is proposed with PWM rectifier and a battery for storing the extra wind energy.
Abstract: Wind power can be used in off-grid systems, also called stand-alone systems, not connected to an electric distribution system or grid. The power conversion unit features a wind-turbine-driven PMSG, a diode rectifier, a buck-boost dc/dc converter, a battery bank, and a dc/ac inverter. In this paper, a distributed generation based on stand alone wind energy conversion system (WECS) using a variable speed permanent magnet synchronous generator (PMSG) is proposed with PWM rectifier and a battery for storing the extra wind energy. The topology for the same condition has been demonstrated using MATLAB Simulink based simulations.
Patent•
29 Jul 2009TL;DR: In this paper, an active ripple energy storage circuit has a first terminal, a second terminal and a third terminal coupled in parallel to the electrical load, the PWM rectifier and the DC link capacitor via the first terminal and the second terminal, the third terminal being coupled to the second and the fourth terminal to the first.
Abstract: An electrical power system includes an alternating current (AC) power source configured to output an AC signal, a single phase pulse-width modulated (PWM) rectifier coupled to the AC power source and to an electrical load; a DC link capacitor coupled in parallel to the load and the PWM rectifier; and an active ripple energy storage circuit. The active ripple energy storage circuit has a first terminal, a second terminal and a third terminal, the active ripple energy storage circuit being coupled in parallel to the electrical load, the PWM rectifier and the DC link capacitor via the first terminal and the second terminal, the third terminal being coupled to the second terminal, the active ripple energy storage circuit being configured to selectively absorb and discharge at least part of the ripple energy.
Patent•
06 May 2009
TL;DR: In this paper, a controllable four-quadrant frequency converter for voltage on direct current side and a method thereof, so as to realize direct-current voltage control, improve the quality of the current on line side and feedback the regenerative electric energy to an electric network.
Abstract: The invention provides a controllable four-quadrant frequency converter for voltage on direct current side and a method thereof, so as to realize direct-current voltage control, improve the quality of the current on line side and feedback the regenerative electric energy to an electric network. The controlling circuit of the frequency converter adopts a single processor and an integrated chip to drive a converter on line side and a converter on motor side to alternately fulfill the functions of rectification and inversion under different loaded states. The processer designed by pipelining can quicken the calculation speed and meets the requirement of real time of controlling of the PWM rectifier, due to the adoption of the vector control and power disturbance compensation method, the unity power factor can be realized when the bidirectional flow of the energy is ensured, the voltage on the direct current side can be accurately controlled, when the load is disturbed, the fluctuation range is smaller, the current on direct current side is estimated, the cost of the products can be saved, the estimation method adopts direct direct-current estimation instead of non alternating current estimation, the disturbance compensation fluctuation is reduced, and the system power is more smooth.
TL;DR: The new switching schedule improves the quality of line current and results in better dynamic performances as compared with the conventional switching table (ST-DPC) while the predictive direct power control (PDPC) of three-phase boost rectifier is presented.
Abstract: The switching table based direct power control (ST-DPC) of three-phase PWM rectifier is analysed in this paper. The approach for constructing switching tables used in DPC is presented and an improved switching table (IST-DPC) is proposed. The new switching schedule improves the quality of line current and results in better dynamic performances as compared with the conventional switching table (ST-DPC). In addition, the predictive direct power control (PDPC) of three-phase boost rectifier is presented, and simulation results (in MATLAB/SIMULINK environment) are compared with those generated by ST-DPC and IST-DPC approaches. Advantages and limitations of each control scheme are highlighted and conclusions regarding applications, quality of current waveforms and burden of calculations are presented.
Patent•
30 Dec 2009
TL;DR: In this article, a symmetric three-section voltage vector pulse width modulation method for a three-level PWM rectifier is proposed, which comprises the following steps: 1. Voltage vector area division: dividing one sector according to every 60 degrees, setting up three small areas in each sector, and calculating by taking quadrant as a unit; 2. voltage vector synthesis: using the adjacent three-voltage vector synthesis of each area according to the areas divided in the step one; 3. voltagevector acting time calculation: calculating the acting time of each synthesized voltage vector of
Abstract: The invention discloses a symmetrical three-section voltage vector pulse width modulation method for a three-level PWM rectifier, which comprises the following steps: 1. voltage vector area division: dividing one sector according to every 60 degrees, setting up three small areas in each sector, and calculating by taking quadrant as a unit; 2. voltage vector synthesis: using the adjacent three-voltage vector synthesis of each area according to the areas divided in the step one; 3. voltage vector acting time calculation: calculating the acting time of each synthesized voltage vector of each area according to V-t characteristics; and 4. voltage vector pulse width modulation: utilizing the voltage vector acting time calculated in the step three to carry out the voltage vector pulse width modulation, i.e. realizing the voltage vector pulse width modulation by a DSP+CPLD three-level PWM rectifier system based on a logical approach. The method realizes the self-balancing of the voltage vector pulse width modulation; the voltage vector subareas are fewer, and the algorithm is simple.
23 Jul 2009
TL;DR: In this paper, two kinds of photovoltaic array simulators based on voltage source PWM rectifier and current source PV rectifier are presented, which can be adopted for different applications and can match the output characteristic of PV array and test the performance of PV power generators well.
Abstract: It is urgent to develop the photovoltaic (PV) array simulator for designing and research the photovoltaic power generation system to save cost and space. Therefore, two kinds of photovoltaic array simulators based on voltage source PWM rectifier and current source PWM rectifier are presented. They can be adopted for different applications. By the way of PV cells mathematical model, the output characteristics of PV array simulators are corresponded to the output characteristics of PV array. By establishing the simulation model of entire system, the output characteristics of PV array simulators and the stability of the entire system combined with PV power generator are analyzed and compared. The results of simulation show their characteristics of these two kinds of PV array simulators, and prove that they can match the output characteristic of PV array and test the performance of PV power generators well. So it will benefit the photovoltaic manufactures significantly.
17 May 2009
TL;DR: In this article, a feedforward compensation method was proposed to decrease the inrush current in a three-phase voltage source PWM rectifier with a TMS320F2812 DSP.
Abstract: Usually, the control method with voltage and current PI regulators in synchronous rotating frame is applied to three-phase voltage source PWM rectifier. It is easy to generate inrush current during startup period. A slow ramp reference current is commonly used to achieve the soft starting, but not quite effective. The paper first analyzed the cause of inrush current and obtained the shortcomings of traditional PI method and slow ramp reference method. Then a feedforward compensation was proposed to decrease the inrush current. After analysis and comparison, the feedforward compensation method has the best performance. Finally, an experimental prototype of a three-phase voltage source PWM rectifier controlled by a TMS320F2812 DSP was built and tested. The experimental results verified the validity of the analysis.
16 Oct 2009
TL;DR: In this article, the authors proposed a novel traction supply system for urban rail transportation, based on a multi-paralleled structure of PWM rectifiers, which overcomes the defects of its conventional counterpart.
Abstract: the application of conventional traction supply system for urban railway transportation implies huge energy waste and electrical pollution, in which the energy regenerated from the braking of vehicles cannot be feedback into AC grid. What’s more, its DC output voltage fluctuates seriously with external loads, and AC harmonics on the grid side forms electrical pollution to the outside. This paper proposes a novel traction supply system for urban rail transportation, based on a multi-paralleled structure of PWM rectifiers. Fully exerting the merits of the PWM rectifier, such as a controllable DC output characteristic, less harmonics on grid side, availability of unity power factor as well as the capability of bi-directional power flow, our novel system overcomes the defects of its conventional counterpart. Under the Phase-shift Space Vector Pulse Width Modulation (PS-SVPWM) mechanism, the equivalent switching frequency of the system can be further reduced. Another adopted mechanism in the system is balance control of the PWM rectifier modules’ loads. A subsystem for remote control and monitoring of the system is also developed with Ethernet technology and virtual instrument theory. The design has been testified with experiments on a prototype set up in lab, and related results are given in the last part of this paper.
17 May 2009
TL;DR: In this paper, two one-stage low-pass filters are adopted instead of the pure integrator in the virtual line-flux-linkage observer, which can steady the phase and amplitude.
Abstract: In the control of PWM rectifier, it can restrain harmonic and interference effectively by constructing a virtual line-flux-linkage to serve as the oriented vector. However, there are some problems in the conventional method, such as the error of amplitude, the shift of phase angle and the nondeterminacy of initial oriented angle. In the thesis, two one-stage low-pass filters are adopted instead of the pure integrator in the virtual line-flux-linkage observer, which can steady the phase and amplitude. Furthermore, a novel method of voltage estimate at the three-level rectifier terminals is advanced based on the simplified SVPWM algorithm. The good dynamic and static performance under the proposed control strategy is verified by simulation and experiment.
17 May 2009
TL;DR: In this article, the three-level PWM rectifier topology has been studied, and the decoupled state-space equations in synchronous rotating reference frame (d-q frame) were derived.
Abstract: The three-level PWM rectifier topology has been studied in this paper, and the decoupled state-space equations in synchronous rotating reference frame (d-q frame) were derived. The hierarchical controller structure is adopted, namely, the inner current-loop is responsible for reference current tracking and the outer voltage-loop is responsible for load regulation. The design methodologies for proportional-integral (PI) controllers are presented, for the inner current-loop and outer voltage-loop, respectively. The proposed three-level PWM rectifier based on space vector pulse-width-modulation (SVPWM) strategy is simulated using MATLAB/SIMULINK. Simulation results demonstrate that the proposed three-level PWM rectifier provides excellent performance both in steady-state and dynamic load variations. Pure sinusoidal waveforms can be achieved in grid currents with a unity power factor. Besides, energy feedback is realized.
17 May 2009
TL;DR: In this article, a novel direct-drive wind generation system based on three-phase Z-source inverter is presented, which combines the traditional PWM rectifier model and equivalent model of the z-network.
Abstract: In this paper, a novel direct-drive wind generation system based on three-phase Z-source inverter is presented. Mathematical model of three-phase Z-source inverter is proposed by combining the traditional PWM rectifier model and equivalent model of the z-network. How variational shoot-through duty ratio affect the system is analyzed. The control method of acquiring stable Z-network capacitor voltage and decoupled d-q axis current is proposed. The relationship between variety of the shoot-through duty ratio and one of generator speed is expatiated, and a maximum power point tracking (MPPT) algorithm based on maximum power curve is designed. The whole process of tracking maximum power is analyzed by sample chart. The results of experiment on the designed prototype verify the correctness of theoretical analysis and the validity of control method.
Patent•
11 Feb 2009
TL;DR: In this paper, a composite type traction power supply device which can enhance the performance of the entire power supply devices and reduce the cost is presented, where a central control unit calculates the given values of a d shaft current and a q shaft current of each PWM rectifier unit by detecting the two-phase alternating current voltage, the twophase alternating-current and the direct-current output voltage of the diode rectification set.
Abstract: The invention relates to a composite type traction power supply device which can enhance the performance of the entire power supply device and reduce the cost The traction power supply device adopts the technical proposal that the traction power supply device comprises a diode rectification set (1), and is characterized in that a PWM rectification set (5) and a central control unit are also arranged, wherein, the diode rectification set and the PWM rectification set are respectively connected at the alternating current side and the direct current side, so as to form parallel relationship; the central control unit calculates the given values of a d shaft current and a q shaft current of each PWM rectifier unit in the PWM rectification set by detecting the two-phase alternating-current voltage, the two-phase alternating-current and the direct-current output voltage of the diode rectification set, transmits the given values to each PWM rectifier unit in the PWM rectification set through a CAN network and realizes coordination control for the diode rectification set and the PWM rectification set The invention also discloses a control method of the device
01 Jan 2009
TL;DR: In this paper, a simple and quick prediction of the hysteresis band is added to a phase-locked-loop control to ensure constant switching frequency and synchronization of modulation pulses independently on the system parameters.
Abstract: Φ Abstract - In this paper, a novel adaptive hysteresis band current control technique based on predictive reasoning for three-phase PWM rectifier is presented. A simple and quick prediction of the hysteresis band is added to a phase-locked-loop control to ensure constant switching frequency and synchronization of modulation pulses independently on the system parameters. The proposed technique allows the advantages of quick response, robustness, good current tracking accuracy and minimal supply current ripples. The three-phase PWM rectifier has the characteristic of drawing nearly sinusoidal current with stable switching frequency and tight control of the position of modulation pulses. The simulation results show that the designed technique can improve three-phase PWM rectifier performance noticeably.
20 Oct 2009
TL;DR: In this article, an optimized three-level switching table with high power regulation intensities is constructed in order to improve the tracking capabilities of power loops, and an energy regulator is designed based on the power equations of the energy interfaces to control the energy stored in the dc-link capacitors.
Abstract: This paper investigates the energy interfaces in three-level pulse width modulation (PWM) rectifier and proposes a novel direct power control (DPC) strategy. An optimized three-level switching table with high power regulation intensities is constructed in order to improve the tracking capabilities of power loops. An energy regulator is designed based on the power equations of the energy interfaces to control the energy stored in the dc-link capacitors and to maintain the required output voltage. Compared with the conventional three-level DPC, the novel strategy achieves better performances. Simulation and experimental results have verified the validity and feasibility of the proposed method.
Patent•
30 Dec 2009
TL;DR: In this paper, a high power factor cascade stage speed regulating device of phase-shifting chopped waves was proposed, where a rotor side of an inner feedback motor is connected with two three-phase rectifiers through a Y/Y/Delta transformer to form a 12-pulse rectifier for reducing the content of harmonic wave at the rotor side and improving the power factor of the rotor.
Abstract: The invention relates to a high power factor cascade stage speed regulating device of phase-shifting chopped waves A rotor side of an inner feedback motor is connected with two three-phase rectifiers through a Y/Y/Delta transformer to form a 12-pulse rectifier for reducing the content of harmonic wave at the rotor side and improving the power factor of the rotor side; a direct current side of the rectifier is connected with a phase-shifting chopper to reduce direct current pulsation and improve the reliability and stability of the chopper; the back ends of two choppers are connected with a common bus; the two choppers feedback the inversed current to the power grid through a PWM rectifier, which can not only reduce the content of harmonic wave and improve the power factor, but also prevent inversion and subversion effectively The invention can not only reduce the harmonic current at the rotor side, but also reduce the harmonic current at the inversed side, thus reducing the content of harmonic wave of the whole speed regulating device, and greatly improving the power factor of the cascade stage speed regulating device
16 Oct 2009
TL;DR: In this paper, the output of the PV cells is simulated based on the PSCAD/EMTDC platform by using the single-phase VSR PWM rectifier circuit which uses the direct current control as well with the triangular wave current comparison as the control strategy.
Abstract: This paper designs the simulation model of the PV (photovoltaic) cells by using the mathematical model applying in engineering firstly. Then the output of the PV cells is simulated based on the PSCAD/EMTDC platform by using the single-phase VSR PWM rectifier circuit which uses the direct current control as well with the triangular wave current comparison as the control strategy. The results show that the model could simulate the output of the PV cells well and could also meet the V-I characteristics of the loads. This model will have good practicability for the further design of MPPT algorithm applying in the photovoltaic grid-connected system too.
28 Dec 2009
TL;DR: The new single-phase PWM rectifier with compensate circuit improves the dynamic performance of the system and the output voltage fluctuation is reduced obviously.
Abstract: The single-phase voltage source PWM rectifier VSR is widely used in improving the quality of the power energy. Recently, lots of researches have been investigated for the Single-Phase PWM rectifier. The PWM rectifier based on the small signal model is proposed in this paper. The new single-phase PWM rectifier with compensate circuit improves the dynamic performance of the system . Also, the output voltage fluctuation is reduced obviously. Simulation results are presented to verify the feasibility and effectiveness of the proposed method. Keywordssingle-phase; PWM rectifier; small signal model
Patent•
26 Aug 2009
TL;DR: In this article, a passivity-based control system for the voltage type PWM rectifier supplied by the unbalanced power supply is established based on the novel synchronous rotation transformation and the new passive energy control law.
Abstract: The invention researches the problem of controlling a voltage PWM rectifier when a power supply is unbalanced according to a principle that the change of a physical quantity depends on energy changes. On the basis of the passivity of a novel synchronous rotation transformation and a rectifier, a new passive energy control law is determined. The novel synchronous rotation transformation can transform an unbalanced system of the PWM rectifier supplied by an unbalanced power supply into a quasiequilibrium system. The passive energy control law determined by a novel damping injection method can decouple a system, transform a non-linear system into a linear system, and simultaneously converge the rectifier to an expected stable point quickly. A passivity-based control system for the voltage type PWM rectifier supplied by the unbalanced power supply (referring to an attached figure) established based on the novel synchronous rotation transformation and the new passive energy control law has excellent movable and still performances, and achieves unit power factors, current on-line side sine, and direct current voltage constant control.
20 Oct 2009
TL;DR: An accurate theory of calculating the DC link capacitor voltage ripple and current ripple for SPWM inverters and PWM rectifiers, which are most commonly used in series hybrid electric bus (SHEB) converter/inverter systems at low speed, is presented in the paper.
Abstract: An accurate theory of calculating the DC link capacitor voltage ripple and current ripple for SPWM inverters and PWM rectifiers, which are most commonly used in series hybrid electric bus (SHEB) converter/inverter systems at low speed, is presented in the paper. Most of all, the results are analyzed and summarized into graphs, which helps to find the right capacitance value for a given voltage ripple tolerance and the rms ripple current that the capacitor has to absorb. An inverter prototype is built and experimental results are demonstrated to verify the theoretical calculation.