Performance improvement of repetitive controlled PWM inverters: A phase‐lead compensation solution

The compensation of the phase lag plays an important role in the improvement of convergence rate, tracking accuracy, and robustness of repetitive controller. However, it is often difficult to compensate the system phase lag exactly due to variation of the load and unknown disturbances. An alternative way is to provide a simple but effective phase compensation to compensate the phase lag in a frequency band that contains the major tracking error components. With this motivation, a repetitive control scheme with a linear phase‐lead compensator is proposed and applied to the control of constant‐voltage constant‐frequency pulse‐width modulated DC–AC inverters. Detailed analysis of phase compensation on system stability is provided, and conditions for the design of phase compensation are derived. The experimental results under different loads and load changes show that the proposed scheme can achieve high tracking accuracy, low total harmonic distortion, and fast dynamic response. Copyright © 2008 John Wiley & Sons, Ltd.     

Three‐Phase AC Filter Inductor Design for Three‐Phase PWM Inverter for Conversion Efficiency Improvement at Low Load

The inductor losses in a three‐phase ac filter inductor used in a three‐phase pulse‐width modulation (PWM) inverter are evaluated. First, a three‐phase inductor is designed to obtain the same value of inductance for each phase. Then, based on the design, a three‐phase inductor that uses two magnetic materials is proposed. The conversion efficiency of a 1 kVA three‐phase PWM inverter that uses the conventional and proposed ac filter inductors is simulated. Simulation results show that conversion efficiency improves. Finally, the conversion efficiency of an actual three‐phase 1 kVA PWM inverter that uses the conventional and proposed ac filter inductors is measured. In the experiment, the conversion efficiency obtained for the case of the proposed inductor improves by approximately 1% at low power load as compared to the conventional inductor. Furthermore, the calculated inductor losses are in good agreement with measured losses. Improvement in efficiency is verified trough simulations and experiments.     

大功率组合式三相逆变器对称输出控制

为了满足大功率高性能三相电源的需要,针对组合式三相逆变器结构特点,提出了一种正弦脉宽相位调制的控制策略,在各相电压、电流瞬时值双环独立控制基础上,通过电压、相位外环分别对各相参考正弦的脉宽和相位调制,有效地解决了三相电压的幅值和相位的对称性问题.仿真和12 kW的整机实验证明了方案的正确性,并获得了满意的效果.     

Optimal control of a single‐phase H‐bridge DC–AC inverter

The control of switched power converters has been mostly accomplished using pulse width modulation (PWM). Under this type of control, it has been shown in literature that DC–AC current mode single‐phase inverter may exhibit chaotic behavior if the proportional controller of the PWM modulator is badly tuned. In this work, we present a novel method to control the inverter using an optimal control approach. Our method consists in defining the switching instances in order to achieve the reference current with minimum error. To illustrate the efficiency of our proposed method, numerical simulations and comparison with the proportional and integral controller as well as to the proportional and resonant controller are presented. Copyright © 2015 John Wiley & Sons, Ltd.     

基于模糊自整定PI控制和重复控制的单相正弦脉宽调制逆变电源复合控制方案

提出了一种基于模糊自整定比例积分(ProportionalIntegral,PI)控制和重复控制的新型单相正弦脉宽调制(Sinusoidal Pulse Width Modulation,SPWM)逆变电源控制方案.利用模糊自整定PI控制增强系统抵抗参数变化和各种非线性不确定扰动的能力,改善了系统的动态特性;利用重复控制改善系统的稳态特性和增强系统克服同频率扰动的能力.仿真实验结果表明,该控制方案使正弦波逆变电源系统获得了良好的稳态和动态性能,在系统含有不同扰动频率时仍具有较好的控制品质.     

基于分数阶重复PI控制的并网逆变器设计

针对三相LCL型并网逆变器并网电流中存在周期性谐波以及滤波电路产生谐振尖峰的问题,提出一种基于分数阶相位超前法的重复PI复合控制方案。采用分数阶相位超前设计,克服整数阶相位超前法相位校正精确度不高的问题,保证系统的稳态输出特性;将LCL滤波器中电容并联的电阻进行等效,替代重复控制补偿器中的低通滤波器,简化重复控制器的参数设计;在重复控制器中叠加PI控制,克服了重复控制器动态响应差的问题。通过仿真分析和实验验证,结果表明该方法提高了系统的稳态性能和动态响应速度。     

Space vector pulse‐width modulation for single‐phase full‐bridge Z‐source inverter

The space vector pulse‐width‐modulation technique is extensively applied in the three‐phase power electronics circuits because of its easy digital implementation and wide linear modulation range features. However, the attempt of this technique for the single‐phase Z‐source inverter has seldom been reported because of its unique topology and operational characteristics. In this paper, based on an in‐depth mathematical derivation and theoretical explanation, the space vector pulse‐width‐modulation principles have been discussed in detail. Various implementation schemes are demonstrated, and a comparison study for selected switching patterns is conducted. In addition, the theoretical analysis is validated by both the simulation and experimental results. This work will be helpful for understanding the space vector pulse‐width‐modulation concept and modulation techniques of the single‐phase full‐bridge Z‐source inverters. Copyright © 2013 John Wiley & Sons, Ltd.     

基于积分环节电压微分反馈的逆变器重复控制策略

提出一种积分环节电压微分反馈控制和重复控制相结合的逆变器输出电压数字化控制方案.在不使用电流传感器的前提下,本文提出的补偿器内环能在离散域任意配置逆变器极点位置,大大改善逆变器的动态性能;重复控制外环则致力于稳态精度的提高.积分环节的引入能加强逆变器的抗扰动能力,提高补偿器内环的稳态精度,克服电压微分反馈控制结合重复控制方案引起的"瞬态"电压跌落问题.该方案在一台基于DSP TMS320F240控制系统的逆变器上得到验证,实验结果证明在仅使用输出电压反馈的前提下,该方案能得到高质量的输出波形.     

基于EMTDC的静态同步串联补偿器稳态及暂态特性分析

通过对静态同步串联补偿器(static synchronous series compensator,SSSC)机理的分析,提出了应用正弦脉宽调制(sinusoidal pulse width modulation,SPWM)技术的SSSC控制器实现方案。控制回路设计中通过对正弦参考波相角偏移量的控制使直流电容电压保持恒定。SSSC稳态时的主要作用是对被补偿线路有功功率进行调控,控制器设计中综合考虑了调制系数与补偿方式(容性或感性)之间的相关性,实现了对线路有功功率的灵活控制,响应速度和波动都满足要求。利用PSCAD／EMTDC电磁暂态仿真工具搭建了包括EPRI-7节点系统、SSSC电压源逆变器及其触发控制回路,以及相应的测量、分析模块的详细电磁暂态仿真模型。仿真实现了SSSC的稳态及暂态功能,计算结果证明了控制回路的有效性和系统模型的正确性。同时对直流电容取值及耦合变压器电抗和变比对SSSC特性的影响进行了初步分析。     

A highly efficient single‐phase sine‐wave inverter with single‐switch high‐frequency modulation

This paper presents a highly efficient single‐phase sine‐wave inverter with single‐switch high‐frequency modulation. In this topology, a control circuit is connected at the lower arm of a full‐bridge inverter to control the output voltage across the full‐bridge inverter. The switch at the lower arm of the full‐bridge inverter controls the output voltage of the full‐bridge inverter by increasing or reducing the voltage level at the lower arm of the inverter. This switch of lower arm is controlled by a high‐frequency sinusoidal pulse width modulation (SPWM) switching signal, while the power switches of the full‐bridge inverter operate with a square‐wave switching signal at the line frequency to unfold DC–AC inversion, thus producing a sinusoidal voltage at the load. Both computer simulation and experiment are carried out to verify the performance of the proposed topology. Experimental results from a 1000‐W laboratory prototype are presented to testify and validate the analysis, design, and performance of the proposed topology. The results show that the proposed topology has nearly sinusoidal output voltage and current waveforms with a total harmonics distortion of less than 5%. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.