本文为孟加拉国工程技术大学（作者：Hafiza Sultana）的硕士论文，共54页。

本文提出并分析了改善三相桥式整流器输入电流波形的方案。一般来说，要将线路频率从交流转换为直流，需要使用二极管桥式整流器。为了降低直流输出电压的纹波，在单相整流器的输出端使用一个大的滤波器，在三相整流器中使用一个小的输出滤波器。在单相整流器中，作为滤波器的电容会使变流器的电流变为非正弦。在三相整流器中，输入电流呈周期矩形波，具有非正弦性和不连续性。由于低次谐波的存在，线路中电流的总谐波畸变率越来越高，在许多情况下输入功率因数越来越低。并联有源滤波器（PAF）是解决整流器等非线性负载谐波电流抑制和无功补偿问题的有效方法之一。

本文分析了三相三线制整流负载的有源滤波器设计与控制。针对三相二极管整流器输入电流的谐波抑制问题，提出了一种五阶谐波注入式PWM控制方案。该方法采用直接选择谐波电流的方法。为了抑制输入电流中的主频（五阶）谐波，选择了五阶谐波作为调制源。为了实现IEEE 519-1992标准对THD小于10%的要求，引入了PAF技术。用PSpice对整个方案进行了仿真。仿真结果表明，三相整流器的输入电流在小于10% THD时呈正弦变化。该方案比输入电流整形的无源滤波方法需要更小的输入滤波器，同时保持了较高的效率和良好的输入功率因数。

A scheme for improving the input currentwave shape of three phase bridge rectifier is proposed and analyzed in thisthesis. Generally, to convert line frequency from ac to dc, a diode bridgerectifier is used. To reduce the ripple in the dc output voltage, a largefilter is used at the output of a single-phase rectifier and a small outputfilter is used in a three phase rectifier. The capacitor used as filter causesthe current drawn by converters to become non-sinusoidal in single-phaserectifiers. In three phase rectifiers input current takes the shape of periodicrectangular wave which is nonsinusoidal and discontinuous in nature. Due to thepresence of low order harmonics, the total harmonic distortion of the currentin lines become high and the input power factor in many cases become poor. The parallelactive filter (PAF) is one of the solutions for harmonic current mitigation andreactive power compensation of nonlinear loads like rectifiers. This thesisanalyzes design and control of a PAF for a 3-phase 3-wire rectifier load. Afifth-order harmonic injection PWM concept is developed for the harmonicreduction of the input current of a three-phase diode rectifier. The approachemploys a direct selection of harmonic current. The fifth-order harmonic hasbeen selected to be modulated by Pulse Width Modulator to suppress the dominant(fifth-order) harmonic in the input currents. To achieve THD less than 10%requirement of IEEE 519-1992, PAF technique has been introduced. The totalscheme has been simulated by PSpice. The simulation result shows three phaserectifier’s input current becomes sinusoidal with less than ten percent THD.The scheme requires smaller input filter than passive filter method of inputcurrent shaping and it maintains high efficiency and maintains good input powerfactor at the same time.

1. 引言

2. 并行有源滤波器系统

3. 基于有源功率滤波器的五阶谐波电流抑制

4. 结论与未来工作展望

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