基于基波磁通补偿的串联混合型APF滤波特性分析

Analysis on Filtering Characteristic of Series Hybrid Active Power Filter Based on Fundamental Magnetic Flux Compensation

在基于基波磁通补偿的串联混合型有源电力滤波器(APF)中,由脉宽调制逆变器实现了一个受控基波电流源。串联变压器一次侧的系统电源与系统阻抗、无源滤波器和非线性负载共同作用,使串联变压器二次侧端口呈现一个谐波干扰电压,导致逆变器输出电流中含有一定谐波,影响了滤波器的滤波效果。文中以脉宽调制逆变器为核心,建立了滤波器的数学模型,并对其滤波特性进行了分析。提出了改善其滤波效果的3项有效措施,即适当增大逆变器输出滤波电感、合理选择串联变压器原副方变比、采用电压前馈控制技术。设计了一套基于数字控制的10kVAAPF样机,实验结果证明了原理分析的正确性。

In the series hybrid active power filter based on the fundamental magnetic flux compensation,the pulse width modulation（PWM） inverter acts as a controlled fundamental current source.At the primary side of the series transformer,the system power supply,system impedance,passive power filter and nonlinear loads affect together to lead the terminals at the secondary side of the series transformer to produce a disturbance harmonic voltage,so the inverter output current contains harmonic components,which influences the filtering effect.The mathematical model of the active power filter based on the PWM inverter is established.Then,the filtering characteristics of the active power filter are analyzed.Three measures,i.e.augmenting the filtering inductance properly,selecting the transformation ratio of the series transformer reasonably,and adopting the voltage feed forward control are proposed to improve the filtering effect.The validity of the principle analysis is verified by the experiment on a 10 kVA active power filter prototype.