容错型三相四开关有源电力滤波器及其控制策略

有源电力滤波器(APF)多基于三相六开关拓扑,为提高其运行可靠性,提出一种基于元件冗余的三相四开关容错型APF。针对三相六开关APF的故障判别,应用功率器件承受电压变化识别桥路开路故障;研究了基于谐波检测APF补偿算法与控制电源电流跟踪电网电压APF补偿算法的关系,指出容错型APF切换控制中更适合采用电源电流直接跟踪补偿算法;在三相四开关APF数学模型基础上,研究了直流母线中点偏移对三相四开关APF补偿性能的影响,提出一种直流中点电压差值前馈补偿方法。扩展了配置直流侧储能的情况下,容错型APF的有功调节实现方法;设计了APF容错控制切换策略和硬件实现的电流滞环跟踪控制电路,在建立的三相四开关APF平台上,实验验证了所提方法的有效性。

Fault-tolerant Active Power Filter Based on Three-phase Four-switch Topology and Its Control Strategy

The active power filter (APF) is usually based on three-phase six-switch topology. In order to improve its reliability, a three-phase four-switch redundancy fault-tolerant APF topology is proposed. For an open-circuit fault in the three-phase six-switch APF, a fault identification method based on power device voltage change is proposed. By studying the relation between harmonic detection APF compensation algorithm and supply current tracking APF compensation algorithm, it is pointed out that the latter is more suitable for fault-tolerant APF application. Based on the mathematical model of three-phase four-switch APF, a direct current (DC) bus midpoint voltage feed-forward compensation algorithm is presented to compensate for the side-effect on output imbalance; if energy storage is configured on the DC side, APF active power regulation is also available. The APF fault tolerant switching control strategy is proposed. Based on a three-phase four-switch APF platform, the effectiveness of the proposed method is verified by experiment.