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Showing papers on "PWM rectifier published in 2013"


Journal ArticleDOI
TL;DR: In this article, the authors proposed an improved model predictive direct power control (MPDPC) for a PWM rectifier by using a duty cycle control, which achieves good steadystate performance and quick dynamic response by selecting the best voltage vector, which minimizes the errors between the reference power and the real power.
Abstract: This paper proposes an improved model predictive direct power control (MPDPC) for a pulse width modulation (PWM) rectifier by using a duty cycle control. The conventional MPDPC achieves good steady-state performance and quick dynamic response by selecting the best voltage vector, which minimizes the errors between the reference power and the real power. However, due to the limited number of voltage vectors in a two-level converter, the sampling frequency has to be high to achieve satisfactory performance. This paper introduces the concept of a duty cycle control in the MPDPC by allocating a fraction of control period for a nonzero voltage vector and the rest time for a zero vector. The nonzero vector is selected by evaluating the effects of each nonzero vector and its duration is obtained based on the principle of power errors minimization. Simulation and experimental results prove that, compared to the conventional MPDPC, the proposed MPDPC with duty cycle achieves further steady-state performance improvement without affecting the dynamic response at a small cost of control complexity increase.

259 citations


Journal ArticleDOI
TL;DR: In this article, the performance of a three-phase voltage source pulsewidth modulation (PWM) converter with the grid interfaced photovoltaic energy conversion system being the main application is investigated thoroughly.
Abstract: This paper experimentally investigates the performance of three-phase voltage source pulsewidth modulation (PWM) converter, with the grid interfaced photovoltaic energy conversion system being the main application. In such applications the ground leakage current [common mode current (CMC)] should be much less than an ampere and this is difficult to obtain in transformerless (direct) connected systems. With the target being the reduction of the common mode voltage (CMV) and CMC, the converter performance is investigated thoroughly. Conventional PWM methods [space vector PWM (SVPWM) and discontinuous PWM (DPWM)] and recently developed reduced common mode voltage PWM (RCMV-PWM) methods [active zero state PWM (AZSPWM) and near state PWM (NSPWM)] are considered. The performance of a 1-kW rated PWM rectifier with additional common-mode capacitor emulating a PV system has been experimentally investigated. It is shown that the CMV and CMC of the tested RCMV-PWM methods is significantly less than conventional methods. In particular, NSPWM yields the best overall performance including low ground leakage current, low inverter output (phase current) and input (dc-link current) ripple, and low switching losses. Accounting for the parasitic capacitance effect, the resonant frequency of the common-mode circuit is identified and it is used in the converter design for the purpose of avoiding resonances involving large CMV-CMC. This paper aims help the design engineer select the appropriate PWM method for grid-connected applications and provides some design rules of thumb.

209 citations


01 Jan 2013
TL;DR: In this paper, the authors proposed an active ripple energy storage method that can effectively reduce the energy storage capacitance and feed forward control method and design considerations are provided for single phase PWM rectifiers.
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 project proposed an active ripple energy storage method that can effectively reduce the energy storage capacitance The feed- forward control method and design considerations are provided

157 citations


Journal ArticleDOI
TL;DR: In this paper, the authors presented an easy and robust sensor fault detection and isolation (FDI) and fault tolerant control (FTC) of a single phase PWM rectifier for electrical railway traction application.
Abstract: This paper presents an easy and a robust sensor fault detection and isolation (FDI) and fault tolerant control (FTC) of a single phase PWM rectifier for electrical railway traction application. Catenary current sensor and dc link voltage sensor failures are considered. The FDI method is based on observers and residual generation. The different FDI algorithm steps allow a good detection and isolation of the sensor fault and identify the faulty sensor. The reconfiguration strategy consists of two steps with open loop control and closed loop control working. Simulation results are presented to illustrate the good performance of the FTC procedure. Experimental results are also presented to show the effectiveness of the proposed FDI and FTC algorithms and good performances of the rectifier after the reconfiguration.

153 citations


Journal ArticleDOI
TL;DR: In this paper, the authors proposed an improved DPC for three-phase pulsewidth modulation (PWM) rectifier with simple calculation, where duty cycle control is introduced to allocate only a fraction of control period to the voltage vector selected from conventional switching table in DPC, while a null vector is applied for the rest of time.
Abstract: Conventional switching-table-based direct power control (STDPC) presents irregular power ripples and variable switching frequency, due to the use of predefined switching table and hysteresis comparators. This paper proposes an improved DPC for three-phase pulsewidth modulation (PWM) rectifier with simple calculation. The concept of duty cycle control is introduced in DPC to allocate only a fraction of control period to the voltage vector selected from conventional switching table in DPC, while a null vector is applied for the rest of time. The main advantages of the proposed duty cycle control are twofold. On one hand, it is independent of rectifier parameter such as line-side inductance, hence strong robustness against inductance variations is obtained. On the other hand, the principle to obtain the duty cycle is very simple and easy to implement. Compared to conventional DPC, significant power ripple reduction and more sinusoidal grid current can be observed in the improved DPC. The presented simulation results and laboratory tests validate the effectiveness of the proposed method.

147 citations


Journal ArticleDOI
TL;DR: It is shown that the presented hybrid systems not only can achieve a higher efficiency but also require less silicon area than the single PWM rectifiers they are based on.
Abstract: This paper presents highly efficient three-phase high-power-factor hybrid rectifiers assembled by the parallel connection of a three-phase diode-bridge rectifier and series dc–dc boost converter with a two- or three-level unidirectional pulse width modulation (PWM) rectifier. The idea is to obtain a rectifier that is robust, highly efficient, and simple as a diode-based rectifier and also able to benefit from the PWM rectifier capability to reduce the line current harmonic content. Exemplary three-phase unidirectional hybrid systems built with a two-level delta-switch rectifier and three-level T-type or VIENNA six-switch rectifiers are suggested. Additionally, control schemes, which are appropriate for safeguarding the high-power-factor operation while improving the power sharing rating of the hybrid paralleled rectifier units and able to handle a phase loss without changing the controller structure, are proposed. In order to evaluate the studied hybrid rectifiers, first, an efficiency comparison between two- and three-level hybrid systems with conventional PWM rectifiers is performed. After that, the loss calculations are extended to a variable chip area to allow a fair comparison between these rectifiers. Interestingly, it is shown that the presented hybrid systems not only can achieve a higher efficiency but also require less silicon area than the single PWM rectifiers they are based on. Finally, experimental results obtained with an assembled unidirectional hybrid delta-switch rectifier prototype are presented in order to demonstrate the performance and advantages of this solution.

114 citations


Journal ArticleDOI
TL;DR: In this article, a detailed design process for an HT SiC three-phase PWM rectifier that can operate at ambient temperatures above 100°C is described, and an edge-triggered HT gate drive is also proposed to drive the designed power module.
Abstract: High-temperature (HT) converters have gained importance in industrial applications where the converters operate in a harsh environment, such as in hybrid electrical vehicles, aviation, and deep-earth petroleum exploration. These environments require the converter to have not only HT semiconductor devices (made of SiC or GaN), but also reliable HT packaging, HT gate drives, and HT control electronics. This paper describes a detailed design process for an HT SiC three-phase PWM rectifier that can operate at ambient temperatures above 100°C. SiC HT planar structure packaging is designed for the main semiconductor devices, and an edge-triggered HT gate drive is also proposed to drive the designed power module. The system is designed to make use of available HT components, including the passive components, silicon-on-insulator chips, and auxiliary components. Finally, a 1.4 kW lab prototype is tested in a harsh environment for verification.

102 citations


Journal ArticleDOI
TL;DR: In this paper, the authors proposed a smart charger for electric vehicles with a power-quality compensator, which consists of four-leg insulated-gate bipolar transistors (IGBTs), and three legs are used for a single-phase full-bridge-based pulsewidth-modulated (PWM) rectifier, which converts power from ac to dc during the battery-charging operation or from dc to ac during battery discharging operation.
Abstract: In this paper, we propose a smart charger for electric vehicles with a power-quality compensator. The proposed smart charger consists of four-leg insulated-gate bipolar transistors (IGBTs). Three legs are used for a single-phase full-bridge-based pulsewidth-modulated (PWM) rectifier, which converts power from ac to dc during the battery-charging operation or from dc to ac during the battery-discharging operation. This PWM rectifier can compensate reactive and unbalanced active currents on single-phase three-wire distribution systems because the third leg is connected to the neutral line of single-phase three-wire distribution feeders. The fourth leg is used as a bidirectional dc-dc converter for battery-charging and battery-discharging operations. The three-leg PWM rectifier uses only constant dc-capacitor voltage control, which is commonly used in active power line conditioners. Thus, the authors have developed the simplest possible control method for a single-phase power-quality compensator. The basic principle of the proposed smart charger is discussed in detail and then confirmed by digital computer simulation using PSIM software. A prototype experimental model is constructed and tested. Experimental results demonstrate that balanced source currents are obtained on the secondary side of the pole-mounted distribution transformer for battery-charging and battery-discharging operations.

64 citations


Journal ArticleDOI
TL;DR: In this paper, a hybrid passive-active damping solution with improved system stability margin and enhanced dynamic performance is proposed for high power grid interactive converters for line side LCL filter based active rectifier/inverter applications.
Abstract: A hybrid passive-active damping solution with improved system stability margin and enhanced dynamic performance is proposed for high power grid interactive converters. In grid connected active rectifier/inverter application, line side LCL filter improves the high frequency attenuation and makes the converter compatible with the stringent grid power quality regulations. Passive damping though offers a simple and reliable solution but it reduces overall converter efficiency. Active damping solutions do not increase the system losses but can guarantee the stable operation up to a certain speed of dynamic response which is limited by the maximum bandwidth of the current controller. This paper examines this limit and introduces a concept of hybrid passive-active damping solution with improved stability margin and high dynamic performance for line side LCL filter based active rectifier/inverter applications. A detailed design, analysis of the hybrid approach and trade-off between system losses and dynamic performance in grid connected applications are reported. Simulation and experimental results from a 10 kVA prototype demonstrate the effectiveness of the proposed solution. An analytical study on system stability and dynamic response with the variations of various controller and passive filter parameters is presented.

50 citations


Journal ArticleDOI
TL;DR: In this article, the relationship between instantaneous power and voltage vectors is derived mathematically from the model of three-phase three-level voltage source PWM rectifier, and a direct power control (DPC) scheme for three level PWC rectifier is presented.
Abstract: This study presents a new control strategy for three-level neutral point-clamped pulse-width modulated (PWM) rectifier. The relationship between instantaneous power and voltage vectors is derived mathematically from the model of three-phase three-level voltage source PWM rectifier, and a direct power control (DPC) scheme for three-level PWM rectifier is presented. An optimal switching table is established, from which appropriate voltage vectors can be selected to control active and reactive power directly. Principle for vector switching to avoid excessive ΔV in phase and line-to-line voltages and balance strategy for the neutral point potential are also discussed. A digital-signal-processor-based experimental system is developed to implement a series of experiments. The obtained results have verified the theoretical approach, and the three-level PWM rectifier with proposed DPC exhibits advantages of simple algorithm and good dynamic performance, compared with conventional voltage-oriented control.

49 citations


Proceedings ArticleDOI
17 Mar 2013
TL;DR: In this article, a ripple-port is added in parallel with the output of the PWM rectifier to filter the double-line-frequency ripple using the minimum capacitance necessary for power buffering.
Abstract: This paper proposes a new technique for double-frequency ripple-power decoupling in a single-phase PWM rectifier that does not require an electrolytic capacitor, which improves the reliability of the system for long-life applications such as LED lighting. A ripple-port is added in parallel with the output of the PWM rectifier to filter the double-line-frequency ripple using the minimum capacitance necessary for power buffering. Hence, a very small, highly reliable film capacitor is used, which will improve the reliability dramatically compared to the bulky electrolytic capacitor option, which increased the power density of the system. The proposed topology doubles the MTBF increases the lifetime by one order of magnitude. Moreover, the design and control of the ripple-port is independent from the PWM rectifier circuit, so it can be dropped in as an auxiliary circuit to an existing design.

Proceedings ArticleDOI
28 Oct 2013
TL;DR: In this paper, the authors investigated the optimal ratio kL, opt = Lcm, 1/LDM, 1, which minimizes the volume of the main LC stage of the DM/CM EMI input filter.
Abstract: Three-phase voltage source AC-DC converters disclose a differential mode (DM) and a considerable common mode (CM) bridge-leg output voltage at the switching frequency, which need to be filtered by an EMI input filter to comply with conducted EMI standards (e.g. CISPR 11) at the mains terminal. Additionally, the EMI filter (which in this paper includes the boost inductor) should usually limit the maximum peak-to-peak bridge-leg output current ripple, to which a DM and CM component contribute, to 20%-40% of the nominal peak current. Typically, the DM current ripple is defined by the boost inductance Ldm, 1 and the CM current ripple by the CM inductance Lcm, 1. Therefore, a degree of freedom in the filter design exists: different combinations of Ldm, 1 and Lcm, 1 lead to the same peak-to-peak bridge-leg output current ripple. Accordingly, this paper investigates the optimal ratio kL, opt = Lcm, 1/Ldm, 1, which minimizes the volume of the main LC stage of the DM/CM EMI input filter. To achieve a compact filter, it is demonstrated for a 10 kW PWM rectifier system that for kL ≥ 3 the boxed filter volume is almost constant. Additionally, kL, opt = 14 minimizes the stray field of the CM choke Lcm, 1 and leads to a minimal boxed filter volume of 0.43 ltr. for a filter cooled by natural convection.

Journal ArticleDOI
TL;DR: A novel dual single-input single-output (DSISO) model for a three-phase two-level PWM rectifier is proposed, to simplify the complicated structure of multiple input variables and multiple control objectives.
Abstract: A novel dual single-input single-output (DSISO) model for a three-phase two-level PWM rectifier is proposed, in order to simplify the complicated structure of multiple input variables and multiple control objectives. In the proposed model, the three-phase PWM rectifier is equivalent to two single-phase PWM rectifiers in the α-β stationary reference frame, which is easier to analyze than a three-phase PWM rectifier. Based on the DSISO model, the small-signal model is derived, the control-to-output transfer function is deduced, and the design principle of the voltage controller is given. The control strategy is analyzed to determine switching control signals in a switching period. Experimental results confirm the validity of the DSISO model and the feasibility of the control strategy based on DSISO model.

Journal ArticleDOI
TL;DR: The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS) operation in grid/load-connected mode are presented.
Abstract: The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS) operation in grid/load-connected mode are presented. VSWECS consists of a PMSG connected to a AC-DC IGBT-based PWM rectifier and a DC/AC IGBT-based PWM inverter with LCL filter. In VSWECS, AC/DC/AC power converter is employed to convert the variable frequency variable speed generator output to the fixed frequency fixed voltage grid. The DC/AC power conversion has been managed out using adaptive neurofuzzy controlled inverter located at the output of controlled AC/DC IGBT-based PWM rectifier. In this study, the dynamic performance and power quality of the proposed power converter connected to the grid/load by output LCL filter is focused on. Dynamic modeling and control of the VSWECS with the proposed power converter is performed by using MATLAB/Simulink. Simulation results show that the output voltage, power, and frequency of VSWECS reach to desirable operation values in a very short time. In addition, when PMSG based VSWECS works continuously with the 4.5 kHz switching frequency, the THD rate of voltage in the load terminal is 0.00672%.

Patent
03 Apr 2013
TL;DR: In this article, an electric vehicle charging system with high power quality is presented, where an inverter link is added to the charging system, so that the electric vehicle can be connected with a battery pack to charge the battery pack or with an air conditioning load for electric discharge according to load change conditions.
Abstract: The invention discloses an electric vehicle charging system with high power quality. A direct-current charger of the electric vehicle charging system is an electric vehicle charger on the basis of a voltage type PWM (pulse width modulation) rectifier, and a control system of the PWM rectifier is of a double-closed-loop control structure with a traditional outer PI (proportion integration) regulating voltage loop and an inner dead-beat control current loop. Harmonic current which is injected into a power grid by the electric vehicle charging system is reduced, and the power quality of the power grid is improved. Besides, an inverter link is added to the electric vehicle charging system, so that the electric vehicle charging system can be connected with a battery pack to charge the battery pack or can be connected with an air conditioning load for electric discharge according to load change conditions (namely a peak period, a valley period and the like) of the power grid, energy can flow in positive and negative directions, the electric vehicle charging system can run in a rectification state to receive the energy from a power-grid side, can also run in an inversion state to transmit the energy to the load, and runs in an approximate unity power factor state, and the utilization efficiency of power resources is improved.

Proceedings ArticleDOI
17 Mar 2013
TL;DR: In this paper, a new medium-voltage (MV) wind turbine generator (WTG) - energy storage grid interface converter topology with medium-frequency (MF) link transformer isolation is introduced.
Abstract: In this paper, a new medium-voltage (MV) wind turbine generator (WTG) - energy storage grid interface converter topology with medium-frequency (MF) link transformer isolation is introduced The system forms a 3-port network in which several series stacked AC-AC converters transform the low-frequency (50/60 Hz) utility MV into MF (04 to 2 kHz) AC voltage by modulating it with MF square wave This voltage is then fed to the MF transformer primary windings The secondary and tertiary windings interface with the WTG side and the battery energy storage side respectively after power conversion The power generated by WTG is transferred to the MF transformer secondary windings through a 3-phase PWM rectifier and a 3-phase PWM inverter, whereas the power transfer between the energy storage and the tertiary winding occurs through a 3-phase PWM inverter It is shown that the utility grid sinusoidal currents, the battery current and the WTG output currents can be controlled to be of good quality using PI and DQ control strategies Thus, the proposed MF transformer based 3-port topology results in smaller converter weight/volume Moreover, the control can effectively handle voltage sags/swells and provide low voltage ride through (LVRT) capability without significant change in the topology Simulation waveforms along with preliminary experimental results are discussed in this paper

Patent
04 Sep 2013
TL;DR: In this paper, a power quality control system with a fault current-limiting function and a control method was proposed, which consists of a three-phase H-leg PWM rectifier, a threephase four-leg series converter, a thyristor controlled short-circuit branch, a thirristor control bypass reactance branch and a corresponding control method.
Abstract: The invention discloses a novel power quality control system with a fault current-limiting function and a control method thereof The novel power quality control system with the fault current-limiting function comprises a three-phase H-leg PWM rectifier, a three-phase four-leg series converter, a thyristor controlled short-circuit branch, a thyristor controlled bypass reactance branch and a corresponding control method The PWM rectifier and the three-phase four-leg series converter share one direct current side to achieve bidirectional energy conversion, the series converter compensates the fall, the raising and three-phase imbalance of the grid voltage and solves the quality problem of the harmonic voltage, at the same time, the system controls the series converter, the thyristor controlled short-circuit branch and the thyristor controlled bypass reactance branch to limit the current when various short-circuit faults occur on the grid, and thus the purposes of stabilizing the loaded supply voltage, improving power supply quality, protecting the grid and load equipment when short-circuit faults occur and improving the safety and stability of the electric power system are achieved

Patent
06 Feb 2013
TL;DR: In this paper, a model predication control method of a three-phase PWM rectifier under unbalanced voltage was proposed, which is capable of effectively inhibiting second harmonic fluctuation of input power of the rectifier, under the condition of unbalanced power grid voltage.
Abstract: The invention discloses a model predication control method of a three-phase PWM (pulse width modulation) rectifier under unbalanced voltage. The technical scheme mainly includes that the model predication control method of three-phase PWM rectifier under unbalanced voltage includes: negating input active power and input reactive power which are obtained by computation, enabling negated values to pass through proportional resonant controllers, obtaining second harmonic compensation voltages under a two-phase rotating coordinate system by means of compensating voltage computation, then obtaining second harmonic compensation voltages under a two-phase static coordinate system by means of reverse Park transformation, compensating the second harmonic compensation voltages under the two-phase static coordinate system into output voltage subjected to traditional model predication control, enabling voltage vectors with the minimum absolute values, which are differences of current given values and current predication values, to serve as optimal voltage vectors by value function selection, and using the optimal voltage vectors as switching signals for controlling power devices. The model predication control method of the three-phase PWM rectifier under unbalanced voltage is capable of effectively inhibiting second harmonic fluctuation of input power of the rectifier under the condition of unbalanced power grid voltage, and is simple in control structure, short in system delay and capable of simultaneously eliminating secondary pulses of input active power and input reactive power of the system.

Patent
22 May 2013
TL;DR: In this paper, a three-phrase PWM rectifier fault diagnosis method based on wavelet packet analysis and a support vector machine is proposed, which can improve fault diagnosis rate of the threephrase motor-generator set.
Abstract: The invention discloses a three-phrase pulse-width modulation (PWM) rectifier fault diagnosis method based on wavelet packet analysis and a support vector machine. The three-phrase PWM rectifier fault diagnosis method based on wavelet packet analysis and the support vector machine includes the steps: first, building a three-phrase PWM rectifier, determining classification principles and utilizing a wavelet packet arithmetic to analyze a direct current side output voltage of the rectifier; then, conducting energy spectrum and power spectrum analysis on a rebuilt small signal, determining a fault characteristic vector and building a data sample; and finally, choosing a support vector machine kernel function and a parameter, and building a multiple-value classifier so as to achieve fault diagnosis of the three-phrase PWM rectifier. The three-phrase PWM motor-generator set fault diagnosis method based on wavelet packet analysis and the support vector machine can improve fault diagnosis rate of the three-phrase PWM motor-generator set, avoid the problems of the data process and optimization of the traditional test method and effectively improve safety of an electric and electronic rectifier device.

Proceedings ArticleDOI
17 Mar 2013
TL;DR: In this paper, an easy method to design the PR regulator parameters separately, which can guarantee the stability of the system and the performance of the inner current loop, was proposed to eliminate the steady error and current distortion caused by harmonics of the grid voltage.
Abstract: The PWM rectifier with LCL filter has the ability to attenuate the high-frequency current harmonics. However, the model of the system is very complex due to the coupling of the LCL filter under rotating coordinate system. The inner current controller under stationary frame is chosen and it can also easily suppress the negative sequence current under such condition. In order to eliminate the steady error and current distortion caused by harmonics of the grid voltage, a Multi-resonant PR Inner Current Controller was used. Because the system is of high order and complicated, it is difficult to determine the parameters of the regulator. After discussing the function of parameters, this paper proposed an easy method to design the PR regulator parameters separately, which can guarantee the stability of the system and the performance of the inner current loop. A 1.5-kW experimental prototype has been tested to verify the effectiveness of the proposed method.

Proceedings ArticleDOI
21 Nov 2013
TL;DR: A new type charger for electric vehicle (EV) batteries that combines direct power control based on space vector PWM with phase-shifted zero-voltage zero-current-switching and decoupling control for instantaneous active and reactive powers of the grid is described.
Abstract: This paper describes a new type charger for electric vehicle (EV) batteries. The three-level PWM rectifier used Metal-Oxide-Semiconductor-Field-Transistor (MOSFET) with direct power control based on space vector PWM (DPC-SVM) is adopted in the front-end PWM rectifier to achieve high power factor as well as reduce system cost, and full-bridge (FB) converter with phase-shifted zero-voltage zero-current-switching (ZVZCS) is applied to the back-end DC/DC converter to improve system efficiency. Decoupling control for instantaneous active and reactive powers of the grid is realized. Experimental results in 8kW prototype show that during the whole charging process, the system efficiency is higher than 85.1% and the input power factor is higher than 99.9%.

Journal ArticleDOI
TL;DR: In this article, a control strategy for a stand-alone induction generator (IG) driven by a variable speed wind turbine for use in remote area power supply is presented, where the generator is excited simultaneously by a capacitor bank and a PWM rectifier.

Journal ArticleDOI
TL;DR: In this article, a decoupling direct power control of three-phase pulse width modulated (PWM) rectifier with constant switching frequency is presented, which uses SVM technique for the converter switching signal generation.
Abstract: In this paper, a decoupling direct power control of three-phase pulse width modulated (PWM) rectifier with constant switching frequency is presented. This control method, called space vector modulated direct power control (DPC-SVM), uses SVM technique for the converter switching signal generation. Based on the power control model of the converter in synchronous dq coordinates, the control strategy allows to solve the coupling between instantaneous active and reactive power, used as the PWM control variables, and consequently, leads to simple design method of system controller. The proposed DPC–SVM system exhibits several advantages, particularly providing line current very close to sinusoidal waveforms (TDH < 2 %), and good regulation of DC-bus voltage is achieved using PI controller. The simulation calculation was carried out using MATLAB®–SIMULINK® package and results have proven the excellent performance and verify the validity and effectiveness of the control strategy with different loads.

Journal ArticleDOI
TL;DR: In this article, a unit power factor PWM rectifier is designed to solve the problem of harmonic pollution to the power grid that caused by traditional diode rectifier and phase controlled rectifier.
Abstract: To solve the problem of harmonic pollution to the power grid that caused by traditional diode rectifier and phase controlled rectifier, the unit power factor PWM rectifier is designed. The topology structure of the rectifier circuit is introduced and the double closed-loop control strategy in three-phase stationary coordinate system is analyzed. For the deficiency of control strategy, the control strategy in two-phase synchronous rotating coordinate system is proposed. This makes the independent control of active current and reactive current to be realized. The simulation model of the PWM rectifier is built and the effectiveness of the control method proposed in this paper is verified by simulation.

Patent
19 Apr 2013
TL;DR: In this paper, a grid-connected control method based on a virtual resistor with a current source type PWM rectifier was proposed, where the rectifier is equivalent to that a resistor is directly connected with the alternating-current side capacitor in parallel, so that the resonance of the inductor and the capacitor at the alternating current side can be effectively restrained.
Abstract: A grid-connected control method based on a virtual resistor with a current source type PWM rectifier. A grid-connected rectifier consists of a commercial power (5), an alternating-current filtering inductor (4), an alternating-current filtering capacitor (2), a three-phase current source type rectifying bridge (1), a direct-current inductor (6), a direct-current capacitor (8) and a digital controller. The sampled voltage of the alternating-current filtering capacitor is transmitted to a microprocessor (11) to perform digital phase locking, and after phase locking is finished, the voltage and the phase of the alternating-current filtering capacitor are transmitted to an alternating-current current controller (15). The alternating-current current controller consists of a coordinate converter (18), a virtual resistor regulator of d axis (19), a virtual resistor regulator of q axis (20) and a divider (21). The coordinate converter converts the three-phase voltage of the alternating-current filtering capacitor into the voltage under a two-phase static coordinate system, after the voltage is regulated by the virtual resistor regulator, the current passing through the virtual resistor is obtained, the control amount of the alternating-current side is obtained through the divider, the control amount is superposed on the control amount of the direct-current side, a driving signal obtained through a PWM generator (17) is transmitted to a driving board (12), and after the signal is amplified by the driving board, the connection and disconnection of the switches of the three-phase current source type rectifying bridge are controlled. Through digital control arithmetic, the rectifier is equivalent to that a resistor is directly connected with the alternating-current side capacitor in parallel, so that the resonance of the inductor and the capacitor at the alternating-current side can be effectively restrained, the total harmonic distortion in grid-connected current can be reduced, and the stability and the dynamic response characteristic of the direct-current side can not be influenced.

Proceedings ArticleDOI
28 Oct 2013
TL;DR: In this article, a four-leg inverter output stage uses three bridge legs to generate the phase output voltages with reference to the neutral point potential, which is defined by the fourth bridge leg.
Abstract: A control scheme for a high-performance three-phase AC power source is presented. The four-leg inverter output stage uses three bridge legs to generate the phase output voltages with reference to the neutral point potential, which is defined by the fourth bridge leg. The inverter is controlled using a phase-oriented control in order to achieve precise control of each output phase with unbalanced voltages and any kind of load. The neutral potential is controlled for maximum modulation range in case of floating load and controlled to zero for grounded load. The control scheme for the input PWM rectifier stage considers the control of the zero sequence voltage in order to prevent the appearance of circulating currents through the ground loop when the load star point is connected to ground. The control of the circulating currents also allows the safe parallel connection of two or more AC sources. Simulation results under balanced and unbalanced conditions demonstrate the performance of the AC source in terms of output voltage control and prevention of circulating ground currents.

Patent
28 Oct 2013
TL;DR: In this article, a hybrid energy storage system is provided to efficiently convert energy from the battery into AC energy by applying a three-phase multilevel inverter to efficiently transmit the energy from a battery to a load.
Abstract: PURPOSE: A hybrid energy storage system is provided to efficiently convert energy from the battery into AC energy by applying a three-phase multilevel inverter to efficiently transmit the energy from the battery to a load. CONSTITUTION: A battery charging and discharging unit (26) drops an output voltage from a three-phase PWM rectifier to a battery charging voltage. The battery charging and discharging unit boosts a low voltage of a battery to a voltage which is suitable for an inverter. A solar converter (25) converts power from a solar cell to a stable DC voltage. A three-level three-phase inverter changes DC into AC. A controller controls the three-phase PWM rectifier, the battery charging and discharging unit, the solar converter, and the three-level three-phase inverter. [Reference numerals] (23) Three phase rectifier; (24) Three phase inverter; (25) PV DC-DC converter; (26) Battery charging and discharging unit

Proceedings ArticleDOI
25 May 2013
TL;DR: The paper attempts to bring up instantaneous reactive power ip-iq theory and reactive detection algorithm on the basis of the PWM rectifier and proposes voltage-current dual closed-loop control system using fuzzy PI hybrid control to regulate the DC bus voltage.
Abstract: Aiming at solving the problem of harmonic suppression and reactive power compensation, the traditional method is to use reactive power compensation and active power filter. This paper has promoted a new type of Pulse Width Modulation (PWM) rectifier that has the function of harmonic suppression and reactive power compensation which also describes the control method in detail. The paper attempts to bring up instantaneous reactive power ip-iq theory and reactive detection algorithm on the basis of the PWM rectifier. At the same time, it proposes voltage-current dual closed-loop control system using fuzzy PI hybrid control to regulate the DC bus voltage. Thus, not only does the PWM rectifier have the function of rectifying effect, but also achieve the harmonic suppression and reactive power compensation in the power grid. At last analyze the energy flow process and uses the PSIM software simulation to verify functional effects. The simulation results show that PWM rectifier improves the output current waveform and doesn't need additional compensation device.

Patent
27 Nov 2013
TL;DR: In this paper, a light emitting diode (LED) centralized DC (direct-current) power supply system and operating methods thereof are provided. But the proposed operating methods are described as following: the power supply management module adjusts the duty ratio of the three-phase PWM rectifier modules, based on the control signals formed by synthesizing the information about voltage and current of the positive and negative output buses.
Abstract: The invention provides a light emitting diode (LED) centralized DC (direct-current) power supply system and operating methods thereof. The proposed DC power supply system comprises a three-phase AC (alternating-current) input interface, a DC power supply output interface, N+1 three-phase PWM (pulse width modulation) rectifier modules, LED cluster loads and a power supply management module. The proposed operating methods are described as following: the power supply management module adjusts the duty ratio of the three-phase PWM rectifier modules, based on the control signals formed by synthesizing the information about voltage and current of the positive and negative output buses, the three-phase AC input ends, control signals and output of the three-phase PWM rectifier modules, hence AC voltage of power grid can be directly converted into adjustable DC voltage by the PWM rectifier.

Proceedings ArticleDOI
01 Nov 2013
TL;DR: This paper discusses and evaluates the performance of a 50-kVA three-phase AC to DC matrix converter and proposes a space vector modulation based on the virtual AC-DC-AC conversion with four-step commutation patterns for the converter.
Abstract: This paper discusses and evaluates the performance of a 50-kVA three-phase AC to DC matrix converter. Comparing to the conventional converter, which consists of a PWM rectifier and an inverter, the matrix converter does not require a large reactor at the three-phase input side, and require no DC smoothing capacitor at the DC link part. A space vector modulation based on the virtual AC-DC-AC conversion with four-step commutation patterns is proposed for the converter. From the experimental results, the converter can obtain 2.49% THD on the input current and achieves approximately 91.4% efficiency at 40kW.