基于不对称级联逆变器的串联混合有源电力滤波器

Series Active Power Filter Based on Asymmetry Cascade Inverter

提出了一种基于不对称级联多电平逆变器(ACMI)的串联混合有源电力滤波器(SHAPF)及其控制策略。其中,ACMI的各单元逆变器的输出额定电压呈3的幂次方增长,N个单元逆变器的级联可以输出3N电平的阶梯波电压。该SHAPF的串联有源部分被控制为一个幅值由负荷电压基波有效值偏差确定、相位与线路终端电压基波正序分量相同的基波正弦电流源,用同一个装置和同一套控制策略可以实现电源电压扰动(包括谐波、电压降落和不对称等)隔离、负荷谐波电流补偿、负荷节点电压基波幅值调整、线路终端功率因数调整和故障电流限制等功能。与传统SHAPF相比,该SHAPF具有功能多、控制简单、补偿效果好以及其串联有源部分开关损耗小和易于实现大容量化等优点。数学推导和仿真分析验证了该SHAPF及其控制策略的正确性和有效性。

This paper presents a series hybrid active power filter （SHAPF） based on asymmetry cascade multilevel inverter （ACMI） and its control strategy. The output voltages of the voltage source inverter units of the ACMI are increased in the power of 3, which enables the multilevel inverter to output the N-th power of 3 levels voltage. The series active part is controlled as a fundamental sinusoidal current source, whose phase and magnitude are determined by the fundamental positive sequence components of the feede-terminal voltage and the error signals between the root-mean-square （RMS） value of the load fundamental voltage and their reference values, respectively. With this control strategy, this SHAPF can realize the functions including the power supply voltage disturbances （such as harmonics, sags and unbalance） isolation, load harmonic current compensation, load fundamental voltage regulation, power factor correction at the feeder-terminal, and fault current limitation. Compared with the conventional SHAPF, the proposed multifunctional SHAPF based on the ACMI has many advantages, such as simplified control system, good compensation performances, low switching losses, and easy to implement in large scale. The mathematical derivations and digital simulations explain and verify the validity and feasibility of this SHAPF.