Showing papers on "PWM rectifier published in 2018"
TL;DR: A sliding-mode grid voltage observer (SMGVO) is proposed and experimentally verified in this paper for voltage-sensorless operation under an unbalanced network and turns out to be a compact solution for finite-control-set model predictive power control without voltage sensors.
Abstract: A sliding-mode grid voltage observer (SMGVO) is proposed and experimentally verified in this paper for voltage-sensorless operation under an unbalanced network. The fundamental positive sequence component (FPSC) and fundamental negative sequence component (FNSC) are inherently separated in the observer without employing any additional filters. Due to embedded filtering effect, high frequency chattering and harmonic ripples can be well suppressed. Additionally, dc components can be completely rejected. As a result, dc offset would not cause fundamental frequency oscillations in magnitude and frequency of the estimated FPSC and FNSC. Owing to the predictive ability of SMGVO, one-step delay can be directly compensated using state variables in the observer. By combining estimation and prediction into one stage, the designed SMGVO turns out to be a compact solution for finite-control-set model predictive power control without voltage sensors. Theoretical proof is derived to verify that FPSC and FNSC can be accurately estimated and separated. Experimental results obtained from a two-level PWM rectifier confirm the effectiveness of the whole control system.
85 citations
TL;DR: In this article, an algebraic solution (i.e. PI-parameters) based on the first-order plus-time-delay (FOPTD) approximations of the plant dynamics is developed, along with approximating relationships and methodology.
38 citations
01 Jan 2018
21 citations
TL;DR: In this paper, a variable switching frequency PWM (VSFPWM) strategy was proposed for dc-link voltage ripple control in two-level rectifier. But, the voltage ripple is determined by the DC-link current directly, and can be predicted synchronously with PWM signals.
Abstract: The switching frequency is an important control parameter of pulse-width-modulation (PWM) rectifier to reduce switching losses and electromagnetic interference noise. This paper proposed a variable switching frequency PWM (VSFPWM) strategy for dc-link voltage ripple control in two-level rectifier. DC-link voltage ripple is determined by the dc-link current directly, and can be predicted synchronously with PWM signals. A real-time prediction model of dc-link voltage ripple is derived for a common voltage-oriented control PWM rectifier. Then, VSFPWM control is introduced, which changes the switching frequency cycle to cycle with a restriction of dc-link voltage ripple peak value. Furthermore, the dynamic behavior is also observed when the proposed VSFPWM control scheme is adopted. Detail simulation and experimental comparisons are carried out between VSFPWM and normal constant switching frequency PWM, which demonstrate the advantages of the proposed method.
21 citations
TL;DR: In this article, a new maximum current control method for three-phase voltage source PWM rectifier based on its mathematical model in $d$ − $q$ frame and improved by dual-closed-loop control method has been presented.
Abstract: The required peak current and peak voltage of ITER in-vessel vertical stability (VS) coil power supply are up to 80 kA and 2.4 kV, so VS coil power supply needs a pulse width modulation (PWM) rectifier to achieve high power factor operation under the highly transient power demand of the value of 144 MW. A new maximum current control method for three-phase voltage source PWM rectifier based on its mathematical model in $d$ – $q$ frame and improved by dual-closed-loop control method has been presented. This control method meets the fast power charging demand and the dc-side voltage stabilization demand of power supply, and achieves a unity or high power factor operation; its controller is easier to be designed and implemented than dual-closed-loop control at charging mode. The advantages and feasibility of this control method have been verified by simulation and experiment.
17 citations
02 Jul 2018
TL;DR: This article proposes an intelligent approach to the Direct Power Control technique of the PWM rectifier, this control technique improves the performance of PWM converter, called Direct Power control Based on Artificial Neural Network (ANN), applied for the selection of the optimal control vector.
Abstract: This article proposes an intelligent approach to the Direct Power Control technique of the PWM rectifier, this control technique improves the performance of PWM converter, called Direct Power Control Based on Artificial Neural Network (ANN), applied for the selection of the optimal control vector. DPC-ANN ensures smooth control of active and reactive power in all Sectors and reduces current ripple. Finally, the developed DPC was tested by simulation, the simulation results proved the excellent performance of the proposed DPC scheme.
14 citations
TL;DR: In this paper, a three-phase virtual synchronous motor (VSM) control and its possible application for providing fast-charging service from off-board chargers of electric vehicles (EVs).
Abstract: This study introduces a three-phase virtual synchronous motor (VSM) control and its possible application for providing fast-charging service from off-board chargers of electric vehicles (EVs). The main circuit of the off-board charger consists of a three-phase voltage source PWM rectifier (VSR) and a resonant LLC zero-voltage-switching converter. In the proposed control approach, VSM-controlled pre-stage VSR emulates the external characteristics of a synchronous motor (SM), simultaneously, droop control based on charging mode in the VSM can satisfy the demand of the EVs constant-current fast-charging; The post-stage DC–DC converter is responsible for stabilizing the DC bus voltage. The feature of this control strategy is that VSM and fast charging control are implemented by the pre-stage converter, which has better coordination. In the MATLAB, the equivalent synchronous grid of the distribution network supplies to the power battery through the off-board charger, and the effectiveness of the presented control is demonstrated by typical working conditions.
13 citations
01 Oct 2018
TL;DR: A model for a voltage source rectifier which is connected to a PMSG in a wind turbine system, where a FLC based on Voltage Oriented Control (VOC) strategy is used to control the mentioned rectifier.
Abstract: Permanent Magnet Synchronous Generator (PMSG) has been widely used in variable-speed Wind Energy Conversion System (WECS). Fuzzy logic control (FLC) of the generator side converter (rectifier) has the ability to have a good regulation of the DC link voltage regardless of the disturbances caused by the characteristics of the drive train. The main focus of this paper is to present a model for a voltage source rectifier which is connected to a PMSG in a wind turbine system, where a FLC based on Voltage Oriented Control (VOC) strategy is used to control the mentioned rectifier. The simulation results, using Matlab/Simulink, are presented to show the validity of the proposed model for the PWM rectifier compared to those obtained from the PI controller, and to evaluate the performance of the control strategy.
13 citations
01 Oct 2018
TL;DR: Simulation and experimental results demonstrated better performance and verified the validity of the new command with the Petri nets applied to the bridge rectifier connected to the electrical network.
Abstract: This article proposes a new simple scheme for direct power control of a PWM rectifier without a switch table and voltage sensor. The selection of the switching state of the converter is based on the transition of a Petri net, using the instantaneous active and reactive power tracking errors and the angular position of the network line voltage estimated as variables of Controller input based on Petri nets. Simulation and experimental results demonstrated better performance and verified the validity of the new command with the Petri nets applied to the bridge rectifier connected to the electrical network.
11 citations
TL;DR: A vector oriented control technique with a two-loop control scheme has been developed for operating a stand-alone three- Phase SEIG for supplying DC loads through a three-phase Pulse Width Modulated (PWM) rectifier and a close agreement between the simulated and experimental results has been confirmed.
Abstract: A vector oriented control technique with a two-loop control scheme has been developed for operating a stand-alone three-phase SEIG for supplying DC loads through a three-phase Pulse Width Modulated (PWM) rectifier. The proposed controller maintains constant load voltage with reduced harmonics at the PWM rectifier input terminals. In addition, it controls the real and reactive power flow between the SEIG and converter system. The proposed control scheme has been implemented employing dSPACE 1103 real-time controller. The successful working of the proposed control strategy has been verified for different operating conditions, by modelling the system in MATLAB/Simulink toolbox and the results are presented. A prototype system consisting of an SEIG, PWM rectifier and associated control circuits, has been built in the laboratory environment and a close agreement between the simulated and experimental results has been confirmed.
10 citations
01 Mar 2018
TL;DR: This work outlines a PWM AC-DC boost converter to accomplish the attractive output DC voltage with least swell, input current with fewer harmonic, a high input power factor, to limit the Total Harmonic Distortion (THD) and to build productivity of the system.
Abstract: The principle goal of this proposed work is to outline a PWM AC-DC boost converter to accomplish the attractive output DC voltage with least swell, input current with fewer harmonic, a high input power factor, to limit the Total Harmonic Distortion (THD) and to build productivity of the system. The boost converters circuits working in the continuous conduction mode is the favored of decision due to its low electromagnetic obstruction contrasted with buck and buck-boost converters. A few endeavors have been taken towards enhancing power factor and current control methodologies that included Proportional Integral (PI) control, hysteresis control, Sliding mode control (SMC) and Fuzzy Logic Control (FLC) were proposed.
TL;DR: In this article, the authors derived the impedance model of PWM rectifier and LLC resonant converter, and the stability analysis of cascade system was studied, where the amplitude of the input impedance is greater than the output impedance in a certain frequency domain.
Abstract: In this paper; the impedance model of PWM rectifier and LLC resonant converter are deduced, and the stability analysis of cascade system is studied. The principle of three-phase PWM rectifier is introduced; and the small signal model in d-q coordinate system is deduced. The expression of dc side output impedance model for PWM rectifier is derived. The LLC resonant converter is operated in a fixed-frequency state, and the LLC resonant converter is modeled as a small signal model. On this basis, the input impedance model expression of the LLC resonant converter is derived. According to the impedance stability criterion, it can seen that the amplitude of input impedance is greater than the amplitude of output impedance in a certain frequency domain. In addition, the Nyquist curve is not around the point (−1,0), which can judge that the cascade system is stable. In simulation software, a cascade system simulation is built and corresponding simulation curves are obtained, which verifies the stability of the cascade system.
20 Mar 2018
TL;DR: This paper introduces a direct power control (DPC) of three-phase PWM rectifier based on a new switching table that gives low harmonic distortion of the current of the grid and operating at zero reactive power.
Abstract: This paper introduces a direct power control (DPC) of three-phase PWM rectifier based on a new switching table. The control principle is the result of a regulation loop between the instantaneous power and the reference powers. The simulation results prove that this advanced switching table have many advantages such as purely sinusoidal input current, low harmonic distortion of input current, unit power factor and adjustment of DC-link voltage. Experimental results are carried out using Dspace 1104. The proposed control algorithm gives low harmonic distortion of the current of the grid and operating at zero reactive power.
01 Sep 2018
TL;DR: This article presents performance evaluation and comparison between Voltage Oriented Control methods for PWM-rectifiers, two levels and three levels, in order to demonstrate the great advantages of using a three-level Neutral Point Clamped (NPC).
Abstract: This article presents performance evaluation and comparison between Voltage Oriented Control (VOC) methods for PWM-rectifiers, two levels and three levels, in order to demonstrate the great advantages of using a three-level Neutral Point Clamped (NPC). The control of the DC bus voltage is carried out using the PI controller. The effectiveness of this approach is illustrated by simulation results using MATLAB/Simulink.
01 Dec 2018
TL;DR: Modelling and analysis of the rectifier system with the proposed phase locked loop (PLL) are presented and performance of the proposed method is compared with that of conventional sensor based vector control through simulations and experiments.
Abstract: Input voltage information is essential for vector control of three-phase active pulse-width modulated (PWM) rectifier. Input voltage sensors impact cost, size and reliability of the PWM rectifier. Existing input voltage sensorless methods either involve extensive mathematical computations to estimate the input voltage or have a control structure significantly different from that of conventional vector control. This work proposes an input voltage sensorless control of PWM rectifier which retains the simplicity of vector control and also reduces the computation requirement. Modelling and analysis of the rectifier system with the proposed phase locked loop (PLL) are presented. The design procedure for the PLL is detailed, and is validated through frequency domain studies. Performance of the proposed method is compared with that of conventional sensor based vector control through simulations and experiments. The responses of both are found to be almost indistinguishable while the proposed method is shown to require reduced computational effort.
Patent•
06 Mar 2018
TL;DR: In this article, a three-level PWM rectifier model prediction control method is proposed to improve the dynamic and steady-state performances of the system and reduce the switching loss.
Abstract: The invention discloses a three-level PWM rectifier model prediction control method. The method includes: firstly, establishing a three-level PWM rectifier discrete prediction model, and performing state sampling on a PWM rectifier system; then predicting the state of the PWM rectifier system according to the discrete prediction model to obtain a corresponding predicted value and an expected value; calculating a value function value corresponding to each switching state, comparing the value function values one by one, and obtaining the switching state corresponding to a minimum value functionthrough screening and comparison, wherein the corresponding switching state thereof is the optimal solution of the FCS-MPC. According to the control method, the dynamic and steady-state performances of the system can be effectively enhanced, the output quality of the PWM rectifier is high, the perfectness and the adaptability of offline planning are high, the switching frequency of the system canbe effectively reduced, and the switching loss is greatly reduced.
TL;DR: A fault diagnosis method for open switch fault in single-phase PWM rectifier is proposed based on the switching system theory, which requires no additional sensor, nor extra operation states need to be set.
Patent•
16 Nov 2018
TL;DR: In this paper, a single-phase PWM rectifier dynamic performance optimization control method based on active disturbance rejection control was proposed, which adopts double closed-loop control of a voltage outer loop and a current inner loop.
Abstract: The invention discloses a single-phase PWM rectifier dynamic performance optimization control method based on active disturbance rejection control. The method adopts double closed-loop control of a voltage outer loop and a current inner loop, the current inner loop adopts single-phase DQ current decoupling control and the voltage outer loop adopts active disturbance rejection control. In particular, according to the principle of power conservation, a mathematical model for active DC components isd of single-phase PWM rectifier output DC voltage udc and grid-side AC voltage is deduced; and according to the mathematical model, a voltage outer loop active disturbance rejection controller is designed. In comparison with the traditional single-phase DQ current decoupling control voltage outer loop adopting PI control, the voltage outer loop in the invention adopts active disturbance rejection control, and while grid-side unit power factor operation and DC-side voltage stable control are realized, the dynamic response speed of the system is better and the anti-interference ability is stronger.
01 Oct 2018
TL;DR: This paper proposes new induction heating power supply topologies for forging applications which have high power factor, high efficiency, and large output power, and compares their characteristics and performances.
Abstract: Induction heating can convert electrical energy to thermal energy with high conversion efficiency and quick heating. Currently, a current source rectifier/inverter-fed parallel resonant circuit is widely used as an induction heating power supply for forging applications. However, the conventional induction heating power supplies composed of phase-controlled rectifier and SCR inverter have low efficiency and low power factor at input side, and require additional starting circuitry. So this paper proposes new induction heating power supply topologies for forging applications which have high power factor, high efficiency, and large output power, and compares their characteristics and performances.
13 Sep 2018
TL;DR: In this article, the authors proposed an approach for regulating the PWM three-phase rectifier and for removing the total harmonic distortion (THD) in order to generate a unit power factor non-contaminated device.
Abstract: Some of the best methods for enhancing the efficiency of the transmission of electric energy from source to receiver is the use of pulse width modulators (PWM) This paper proposes an approach for regulating the PWM three-phase rectifier and for removing the total harmonic distortion (THD) in order to generate a unit power factor non-contaminated device This form of regulation is contracted by analogy with direct torque control (DTC) The active and reactive power is the modified factors instead of the torque and stator flux Therefore, a backstepping design for direct power control (DPC) of three phase PWM rectifier is proposed The effectiveness and reliability of the control methods have been checked under various conditions, such as voltage and load variance The simulation results reveal that the backstepping DPC provides outstanding efficiency and robustness
01 Sep 2018
TL;DR: The modeling accuracy of the proposed analytical method to calculate leakage inductances of rectangular winding is confirmed and validates the design methodology of an interleaved zig-zag transformer for a unified ac-dc system.
Abstract: A zig-zag transformer with interleaved secondary windings helps integrate grid (ac) and photovoltaic (dc) power sources in a unified ac-dc power conversion system. Winding leakage inductances of a zig-zag transformer can be utilized as integrated boost-inductances for the PWM rectifier stage, thereby reducing component count and improving overall power density. This paper presents a design methodology of such a zig-zag transformer, suitable for unified ac-dc power conversion system. Using classical approach, appropriate expressions of leakage inductance for windings with rectangular geometry are derived. It is verified using finite element method (FEM) in MagNet. Aiding effect of interleaved winding is examined, which enhances integrated-boost inductance for photovoltaic (PV). An experimental prototype of a 1.0 kW, 415/130 V, 50 Hz delta/zig-zag transformer is built and tested. Thus, analytical calculations are corroborated with the help of 2-D FEM simulation and experimental results. It confirms the modeling accuracy of the proposed analytical method to calculate leakage inductances of rectangular winding and validates the design methodology of an interleaved zig-zag transformer for a unified ac-dc system.
01 Oct 2018
TL;DR: The performance of the proposed regulation technique is compared to the PI regulator to show its effectiveness and the main purpose of this study is to reduce the fluctuation and to reject the impact of load induction motor drive (IMD) on DC-link voltage.
Abstract: In this paper, a direct power and torque control (DPTC) techniques of three-phase pulse with modulation (PWM) rectifier-inverter system using adaptive neuro-fuzzy inference system (ANFIS) controller for DC-link voltage regulation has been proposed. The main purpose of this study is to reduce the fluctuation and to reject the impact of load induction motor drive (IMD) on DC-link voltage. Indeed, the use of Proportional-Integral (PI) controller cannot achieve these objectives due to their disturbances sensitivity problem and limited regulation bandwidth. To avoid these problems, an ANFIS regulator has been designed and the inverter side output power is added to the reference active power in the rectifier side. The performance of the proposed regulation technique is compared to the PI regulator to show its effectiveness.
TL;DR: It has been proved in this paper that the controller is not sensitive to the controlled object, therefore it is suitable for use in complex object model scenarios and effective in improving the AC current quality of the three-phase PWM rectifier.
Patent•
26 Jan 2018
TL;DR: In this paper, a multi-thread convertor equipment connected to an AC power supply and a DC power supply via a traction transformer, an AC circuit breaker and a dc circuit breaker is presented.
Abstract: The invention discloses multi-thread convertor equipment connected to an AC power supply and a DC power supply via a traction transformer, an AC circuit breaker and a DC circuit breaker. The equipmentcomprises an AC precharge circuit, a DC precharge circuit, an isolation conversion switch set, a PWM rectifier, a secondary resonant circuit, an intermediate DC circuit, a VVVF inverter and a VVVF auxiliary inverter. Switches of a plurality of power supplying modes can be achieved via the isolation conversion switch set; the equipment can work at two or more power supplying modes; a deficiency ofsingle use of power supply mode of the traction converter in the prior art can be overcome; the equipment can meet seamless connection between main national line railways and urban railways in the future, and is suitable for various power supplying modes of foreign railways; trans-area and trans-nation transportation demands can be obtained; and the multi-thread convertor equipment can be also suitable for railway power supplying modes of China, African and European areas.
TL;DR: An improved sliding mode control utilizing repetitive control (ISMRC) is proposed for a three-phase pulse- width modulation (PWM) rectifier and can improve both the steady-state performance and the dynamic transient response of a PWM rectifier control system effectively.
Abstract: An improved sliding mode control utilizing repetitive control (ISMRC) is proposed for a three-phase pulse- width modulation (PWM) rectifier. The proposed controller integrates the advantages of both sliding mode control (SMC) and repetitive control (RC) by implementing a structure that embeds an RC controller into the equivalent control branch of an SMC controller. Both a simulation and an experiment are conducted to compare the proposed ISMRC controller with a conventional SMC controller. It is demonstrated that the fifth harmonic distortion of the current of the PWM rectifier system is controlled at 3.3%, the power factor is close to the unit, and the effect on the DC bus voltage is effectively restrained. Therefore, the proposed control strategy can improve both the steady-state performance and the dynamic transient response of a PWM rectifier control system effectively, as well as increase the robustness of the system to load disturbances and parametric uncertainties.
01 Apr 2018
TL;DR: The results indicate that the proposed ANN controller achieves excellent transient performance under unity power factor operation without abnormal instantaneous reactive power fluctuations.
Abstract: This paper presents artificial neural network (ANN) based direct power control of Bidirectional 2-level pulse width modulated (PWM) rectifier. Instead of the traditional PI controller, ANN controller is used in this paper to reduce the peak overshoot and ripple in active power. The Switching table based ANN controller for the direct power control (DPC) is simulated in this paper. And the results indicate that the proposed ANN controller achieves excellent transient performance under unity power factor operation without abnormal instantaneous reactive power fluctuations. The total harmonic distortion (THD) in the source current obtained by the ANN is also less than the THD obtained by the conventional table-based PI controller.
13 May 2018
TL;DR: In this article, a theoretical analysis of the harmonic generation mechanism of PWM-based electric vehicle (EV) chargers considering control strategy is conducted, by establishing simulation models of the charger, the distribution order of characteristic harmonic generated by single charger is analyzed.
Abstract: On the basis of the introduction to the topology of PWM-based electric vehicle (EV) chargers considering control strategy, a theoretical analysis of the harmonic generation mechanism is conducted. By establishing simulation models of the charger, the distribution order of characteristic harmonic generated by single charger is analyzed. Furthermore, the harmonic coupling characteristics of multiple chargers working simultaneously are also discussed. The simulation results show that the harmonics generated by single charger mainly consist of high frequency components, including a small amount of low frequency components. As for multiple chargers, with the increase of the number of the chargers and the charging power, each harmonic current ratio and the current total harmonic distortion both show a downward trend.
01 Nov 2018
TL;DR: In this control strategy, the current loop adopt an improved dual vector based model predictive current control with time delay compensation, which can effectively reduce the input current harmonics.
Abstract: Three phase pulse width modulation (PWM) rectifiers has the problems of input current distortion and output voltage ripple under unbalanced grid voltage. In order to reduce the input current harmonics and the output voltage ripple of three phase PWM rectifiers under unbalanced voltage dips conditions, the stationary frame control strategy is adopted. However, its current loop error will cause higher harmonics of the input currents. To further reduce the input current harmonic, an improved control strategy of the current loop is proposed in this paper. In this control strategy, the current loop adopt an improved dual vector based model predictive current control with time delay compensation, which can effectively reduce the input current harmonics. The effectiveness of the proposed method is confirmed by simulation results.