The Bi-directional Three-Phase PWM Rectifier Inverter for Electric Vehicle Charging Station

Applications of electric vehicles need to build a large number of charging stations. The electric vehicle charging stations communicate with the grid. In V2G （vehicle to grid） mode, electric vehicles can be used as energy storage units and transfer power to the grid. The electric vehicles charge at night to reduce the cost and the grid load, simultaneously to fill the valley. When grid load increases, electric vehicles＇ batteries discharge to the grid to improve the stability of the grid. As distributed storage units, electric vehicles are important components of the smart grid. In this paper, the three-phase PWM （pulse width modulation） rectifier used for smart charging and discharging system of electric vehicles are analyzed and designed. This paper includes the principle of PWM rectifier-inverter and direct current control strategy. Also, the SVPWM （space vector pulse width modulation） and system design of three-phase PWM rectifiers are analyzed. A 10 kW prototype is developed. Simulation and experiment results show that the three-phase PWM rectifiers reach the unit power factor. From the experimental results, PWM rectifier implements the sinusoidal grid current and achieves the unit power factor.

Application of Single-to-Single Phase Matrix Conversion in Conventional Rectifier-Inverter

The principle of single to single phase matrix electric power conversioin is further studied and the conversioin switch function is introduced into conventional rectifier inverter, thus a general character of the two conversion techniques is discovered. It is characteristic of the switch functiion to follow mains voltage distortion and mains frequency drift. By utilizing the merit, unidirectional switch duty rations of the inverter follow the variation of DC link voltage automatically, thus the size of DC link electrolytic capacitor can be reduced considerably, bringing about improved mains side power factor. Corresponding topologies and theoretical and theoretical derivations are given, and so are the simulation results, based on which it is confirmed that the single to single phase matrix conversion technique is potentially useful in large scale production, and the introduction of switch function can yield good economic returns.

不平衡电网下电流源型PWM整流器改进型无差拍控制

三相电流源型PWM整流器运行在电网电压不平衡情况下,引起直流侧及网侧电流存在大量低次谐波,势必对后级变换器供电稳定性、安全性等存在不利影响。针对该问题,首先建立整流器数学模型,推导出不平衡电网下直流侧电压和网侧电流表达式,揭示出系统直流侧和网侧电流产生低次谐波的机理。其次,根据瞬时功率理论设计内环电流参考指令,并利用无差拍控制实现网侧电流对参考电流的跟踪。然而传统无差拍控制存在延时问题,将影响网侧电流的跟随性能,造成电能质量下降。为解决该问题,提出了网侧电流内环改进型无差拍控制,利用两步预测法补偿系统延时。最后,基于Matlab/Simulink平台搭建仿真模型,验证所提控制策略的正确性与有效性。结果表明,所提方法能有效抑制直流侧和网侧电流低次谐波,实现网侧电流正弦化和直流侧电压稳定输出。

基于非线性扰动观测器的三相PWM整流器滑模控制

针对交流微电网中三相PWM整流器的运行状态易受负载扰动、滤波电容参数摄动影响的问题,本文提出一种基于非线性扰动观测器的三相PWM整流器滑模控制方法。首先,将负载扰动、滤波电容参数摄动等视为集总扰动,构建电压环非线性模型。其次,设计非线性扰动观测器,实现集总扰动的在线估计。为实现主动抗干扰控制和滑模抖振抑制,将估计的集总扰动引入到滑模面中,得到了一种含有扰动估计的新型滑模面。最后,基于滑模控制理论设计电压外环滑模控制器,并采用Lyapunov稳定性理论对其进行了稳定性证明。动态性能测试结果表明,非线性扰动观测器能够快速、准确地对集总扰动进行估计;与双环PI控制相比,所提控制的过渡过程时间减少了60%,电压跌落量减少了54%;滤波电容参数变化时,所提控制的动态性能保持良好。稳态性能测试结果表明,与传统滑模控制和双环PI控制相比,所提控制的电流总谐波畸变率分别减少了70%和44%,同时滑模抖振得到了有效地抑制。测试结果证明了所提控制方法的强抗负载扰动能力和良好的滤波电容参数鲁棒性。

双闭环控制的三相电压型PWM整流器的研究

针对传统的不控整流电路中网侧电流谐波很大、晶闸管相控整流电路中深控时网侧功率因数低和闭环控制时动态响应慢等问题,设计出一种引入脉冲宽度调制技术的三相电压型整流器。在完成三相电压型整流器的电压外环电流内环的双闭环控制系统设计的基础上,对其进行了仿真实验。仿真结果表明,与不控或相控整流电路相比,该三相电压型PWM整流电路中,不仅输入电流的谐波大大减小,电能可双向流动,能够实现整流和逆变状态下的单位功率因数运行,还可较好地抑制负载突变时直流侧电压的波动,从而显著提高系统的抗扰能力,真正实现绿色环保和高效节能的高度结合。

基于三矢量的PWM整流器改进模型预测直接功率控制方法

为解决传统模型预测直接功率控制存在的开关频率不恒定、计算量大、共模电压大问题,设计了一种三矢量模型预测直接功率控制方法。该方法通过在单个控制周期内输出三个不同电压矢量,克服了传统方法因连续多个周期输出相同电压矢量造成的开关频率不恒定问题;同时,在两相静止坐标系中,通过优化空间电压矢量图划分方法,采用两个代价函数确定电网电压矢量所在扇区,将算法的遍历次数从27次降至10次,克服了传统方法计算量大的问题;此外,通过去除两个冗余零矢量PPP与NNN,将共模电压抑制在Udc/3以内。最后搭建了5kW实验样机进行实验验证,仿真与实验结果表明,该方法可以有效降低计算量,输出谐波和共模电压抑制效果优于传统方法。

一种基于离散时域模型的单相PWM整流器控制参数多目标优化设计方法

单相PWM整流器一般采用电压外环比例积分、电流内环比例谐振的双闭环控制方法,在实现交流侧高功率因数的同时稳定直流侧输出电压,因此受到国内外学者的广泛研究。然而,在内外环控制参数设计阶段,传统设计方法一般根据经验选取控制参数,参数选取范围较大,且无法量化评估控制参数的时域控制效果,导致参数优化整定困难。为此,该文提出一种基于离散时域模型的内外环控制参数多目标优化设计方法。首先,采用传统设计方法确定电压外环比例、积分控制参数以及电流内环比例、谐振控制参数的安全设计空间;然后,基于离散时域模型将安全设计空间正映射至控制参数的时域性能空间,实现电流内环控制参数对交流侧功率因数以及电压外环控制参数对直流侧电压超调量的量化评估。在此基础上,通过进一步约束性能目标得到性能优化设计空间,考虑内外环控制参数的耦合效应,对内外环性能优化设计空间进行重新组合,再将其映射至性能空间,得到内外环控制目标帕累托最优前沿下的最优设计空间,从中选取内外环控制参数的优化设计点,在典型工况下实验测得的交流侧功率因数为0.981 26,直流输出电压超调量绝对值为1.37%,证明了所提优化设计方法的正确性。

A Space Vector Modulation Based Three-level PWM Rectifier under Simple Sliding Mode Control Strategy

In this paper, a voltage oriented control strategy for three-level PWM rectifier based on Sliding Mode Control (SMC) is introduced in order to obtain fast and accurate response of dc-bus voltage. To verify the validity of the analysis and the feasibility of the proposed control method a set of simulation tests have been conducted using Matlab/Simulink. The simulation results show that compared to the conventional PI controller, the SMC can reduce drastically the three-level rectifier’s voltage fluctuation and improve the dynamic response of dc-bus significantly.

含负载前馈补偿的电流型PWM整流器改进无差拍控制

针对三相电流源型PWM整流器直流侧电压-直流侧电流双闭环控制策略中动态响应速度较慢、参数整定复杂的问题,该文提出一种无差拍预测电流控制与负载功率前馈补偿相结合的改进控制策略。首先,分析三相电流源型PWM整流器在两相静止坐标系中的网侧离散化数学模型,在此基础上,电流内环采用无差拍控制跟踪网侧电流,但由于电感参数与控制延时的影响,将导致网侧电流控制精度及波形质量下降。针对此问题,该文采用改进型无差拍控制策略,并利用根轨迹法对电流内环稳定性能进行分析。在环路设计中,通过在外环上加入负载功率前馈等效电流,加快了系统动态响应,解决了负载突变时直流侧电压超调问题。最后,对传统方案和改进方案进行了对比仿真测试和样机实验,验证了所提控制策略的正确性。

三相电压型PWM整流器的虚拟转矩冲量平衡控制策略

模型预测控制具有结构简单、鲁棒性强和动静态性能良好等优点,因此其在三相电压型PWM整流器系统中得到了广泛应用。然而,模型预测控制的电压外环采用PI线性调节器进行调节,影响了直流侧电压的动态性能。为此提出了虚拟转矩冲量平衡控制策略,从而使直流侧电压仅经过1次调节即可实现快速收敛。为了实现此策略,首先,根据数学模型推导得到了虚拟转矩的表达式;其次,根据负载突变前、后直流侧输出电压保持不变,同时结合功率守恒原则,分析建立了负载突变时的虚拟转矩冲量平衡控制方程,求得零矢量与前进矢量的作用时间;最后,通过仿真和实验实现了三相电压型PWM整流器系统负载突变时的虚拟转矩冲量平衡控制,验证了所提算法的正确性与有效性。

双重化PWM整流器自抗扰模型预测直接功率控制

针对车载双重化脉宽调制(pulse width modulation,PWM)整流器控制性能易受到模型不确定性和列车运行条件(输入电压、功率等级、电路参数等)变化影响的问题,提出一种基于自抗扰控制(active disturbance rejection control,ADRC)和模型预测直接功率控制(model predictive direct power control,MPDPC)的双闭环控制算法。其中,外环基于自抗扰控制理论,构建了基于误差驱动的ADRC(error-based ADRC,EADRC)控制器调节直流侧电压;内环结合基于内模原理的功率补偿方案使用两步MPDPC算法实现电流信号的控制。仿真和实验将所提自抗扰模型预测直接功率控制(ADRC-MPDPC)算法与传统基于比例积分的直接功率控制(proportional integral-based direct power control,PI-DPC)算法和PI-MPDPC方法进行对比,结果表明所提策略在系统启动、负载变化及工况切换等场景表现出更优的动态特性和鲁棒性能。

三相PWM整流器离散空间矢量无模型预测电流控制策略

针对PWM整流器模型预测控制对系数参数准确性高度依赖的问题,提出一种基于离散空间矢量的无模型预测电流控制(MFPCC)策略。该策略通过矢量合成,在每个控制周期应用两个基本矢量,提高了预测电流的准确性;通过峰谷采样,分别测量并存储上一控制周期两个基本矢量作用下的电流梯度;并建立电流梯度方程,从而根据应用矢量的电流梯度进一步更新剩余6个未应用矢量的电流梯度,结合当前时刻的电流采样值,实现未来时刻的电流预测,得到下一时刻最优的虚拟矢量。该方法不依赖于任何系统参数,且消除了传统MFPCC策略中电流梯度更新停滞现象,降低了输出电流谐波。最后,通过实验和仿真验证了所提方法的有效性和优越性。

Analysis and Simulation of a High Performance Quasi Resonant PWM Inverter for Solar Power Generation

A quasi resonant pulse width modulation（PWM） inverter is used in a solar power system to convert the solar panel and battery charger＇s direct current（DC） output to alternating current（AC）.Although much has been published about DC to AC PWM inverters,none of the previous work has shown modeling and simulation results for DC to AC inverters.In this study,we suggest a new topology for a quasi resonant PWM inverter.Experimental results are also presented.

Control of Unit Power Factor PWM Rectifier

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.

New Approach of Multi-Cell Stacked Cell Inverter for Solar Photovoltaic System

In this paper, a new inverter topology dedicated to isolated or grid-connected PV systems is proposed. This inverter is based on the structures of a stacked multi-cell converter (SMC) and an H-bridge. This new topology has allowed the voltage stresses of the converter to be distributed among several switching cells. Secondly, divide the input voltage into several fractions to reduce the number of power semiconductors to be switched. In this contribution, the general topology of this micro-inverter has been described and the simulation tests developed to validate its operation have been presented. Finally, we discussed the simulation results, the efficiency of this topology and the feasibility of its use in a grid-connected photovoltaic production system.

Controlling the output power of soft switching arc welding inverter by two-stage continuous PWM method

The full bridge zero voltage zero current switching （ FB-ZVZCS ） , which could adjust the output power by keeping the duty ratio of lagging leg constant and changing the duty ratio of leading leg, was a common circuit of soft switching arc welding inverter power source. However, when the duty ratio of leading leg was reduced to zero, the output power stayed the constant value instead of becoming zero. The working status and waveforms of some major parameters were studied in this paper while the duty ratio of leading leg was zero. It was concluded that the minimum output power of soft switching inverter was related to the charging voltage of paraUel capacitors, and the output power also could be reduced by reducing the duty ratio of lagging leg. A novel two-stage continuous PWM control method that could switch working-mode between full bridge and half bridge was put forward in this paper. This kind of control method could further reduce the output power of soft switching inverter in order to meet the requirement of low heat input of sheet metal welding.

A type of inverter power supply based on harmonic elimination PWM control

In order to output sine wave with small degree of distortion and improve stability,a type of inverter power supply is designed based on harmonic elimination pulse-width modulation(PWM)control.The rectifier and filter are added to input circuit of the inverter.Single-phrase full-bridge inverter performs the function of converting direct current into alternating current(DC/AC).In the control circuit,single chip micyoco(SCM)AT89C2051 is used for main control chip to accomplish the hardware design of the control system.A given value of output frequency of the inverter is input in the way of coding.According to the output frequency code which is read,SCM AT89C2051 defined harmonic elimination PWM control data which will be selected.Through internal timing control,the switches are switched under this provision of PWM control data.Then the driving signals of the switches in the inverter are output from I/O of SCM AT89C2051 to realize harmonic elimination PWM control.The results show that adding Newton homotopic algorithm of harmonic elimination PWM control to corresponding software of the control system can make the quality of output voltage of the inverter higher and it will have broad application prospects.

Modeling and simulation of induction motor drive system to investigate and mitigate of PWM inverter’s adverse effects

Modeling and simulation of induction motor drive system to investigate and mitigate the adverse effects of PWM inverter based on analysis, modeling and simulation are presented. The estimation of conducted disturbances and other adverse effects of PWM inverter by simulation offer a considerable gain from the economic point of view. For an accurate model of the motor drive system including mains, rectifier, inverter, motor and its long cables, the high frequency parasitic current paths are taken into account. The novel model and its parasitic values for three-phase induction motor system are presented. Finally a new solution for suppressing EMI, common mode voltage, leakage current, bearing current and shaft voltages is proposed and the results show the excellent performances of proposed solution including active and passive filters.

A Space Vector PWM Scheme for Multilevel Inverters Based on Two-Level Space Vector PWM

Ⅰ. INTRODUCTION MULTILEVEL inverters are increasingly being used in high-power medium voltage applications due to their superior performance compared to two-level inverters, such as lower common-mode voltage, lower dv/dt, lower harmonics in output voltage and current, and reduced voltage on the power switches.

Three-Phase Back PWM-PFC Rectifier

A new 3-phase back (or current-source-type) PWM-PFC rectifier is proposed in this paper.The necessity,the advantages and disadvantages of this type PWM rectifier are discussed first.Then,the new power circuit topology and the modulation scheme to eliminate or mitigate the disadvantages and obtain further new advantages of the buck PWM rectifier are introduced.The features of the new rectifier,i.e.,high efficiency,simple modulation process,robustness of the line-current modulation for distortion of the utility voltages and DC current ripples have been confirmed through experimental results obtained from a 12kW prototype.