级联H桥有源电力滤波器直流侧电压控制

DC Side Voltage Balancing Control for Cascaded H Bridge Active Power Filter

直流侧电压的大小和变化将直接影响有源电力滤波器(APF)的补偿性能。经过对功率模型的数学推导,得出通过注入零序电压可以有效地控制各级联H桥相相之间直流侧电压的平衡;同时对模块间电压不平衡及电网电压不平衡下导致的直流侧电压不平衡原因进行了分析;最后结合直流侧全局稳压和模块间均压,构成电压的三层控制,实现了电压均衡和稳定,在电网不平衡的情况下也可以起到较好的效果。仿真结果验证了所提控制策略的有效性。

The size and the changes of DC side voltage will directly affect the compensation performance of active power filter（APF）.The pulse delay,the difference loss of active power and other factors will lead to the voltage imbalance of each module and each phase of cascaded H bridge APF.By analyzing the power model,this paper obtained that the strategy can control the balance and stability of DC side voltage effectively by injecting zero-sequence voltage.It also studied the unbalance reason of DC side voltage for every module of each phase and phase voltage under the unbalanced grid.At last,combining the DC side voltage stabilizing and the single module DC voltage control,the paper presented a three-step decoupling control strategy,which ensures the balance and stability of voltage.It can also play a very good role in the unbalanced grid conditions.The effectiveness of the proposed control strategy was verified by the simulation results.