级联型有源电力滤波器的新型控制策略

A Novel Control Strategy for Cascaded Active Power Filters

基于单周控制方法,作者提出了一种级联型有源电力滤波器的新型控制策略。该控制策略无需进行复杂的无功功率和谐波电流计算,只需检测直流电容电压和系统电流,通过简单计算即可求出各开关管的占空比,将每个工频周期分成6个区间,对桥式变流器而言,在每个区间里只有4个开关运行在高频状态,另外2个开关保持导通或截止。2单元级联型有源电力滤波器的仿真结果验证了其有效性和可行性,表明该控制策略具有检测量少、原理简单、开关频率恒定、易于数字化实现和效率高等优点。

Based on one-cycle control method, a novel control strategy for cascaded active power filter is proposed. As for the proposed control strategy, it is not necessary to carry out complex calculation of reactive power and harmonic currents, so long as to detect the capacitor voltages at DC side and system current; by means of simple calculation the duty ratio of each thyristor can be obtained. Dividing each power frequency period into six intervals, in terms of three-phase bridge converter only four switches operate in high frequency state, and the rest two switches keep on conduction or cut-off. The simulation results of two-unit cascaded active power filters show that the proposed control strategy is effective and feasible; besides, simulation results also show that the proposed control strategy possesses following advantages： less amount of sensors, simple principle, constant switching frequency, easy to digitally implement and high efficiency.