单级式单相逆变器及其低频输入电流纹波抑制

Single-stage Single-phase Inverter and Its Low-frequency Input Current Ripple Reduction

单相逆变器的瞬时输出功率中包含二倍频脉动功率,使得直流侧输入电流中存在大量低频谐波成分。研究了一种电流源型单级式单相逆变电路。基于开关管复用技术,该电路可以在较少的开关器件数量下,同时实现直交功率变换以及低频输入电流纹波抑制的功能。首先分析了该单级式单相逆变电路与常规两级式逆变电路在低频电流纹波传导以及电路模型上的等效性,基于以上分析提出一种控制策略,实现对单级式变换器的直流输入以及交流输出端口特性的同时控制;通过对照性研究,揭示了单级式和两级式逆变电路在器件额定上的相似性;最后通过仿真以及实验验证了控制算法的有效性和性能分析的正确性。

A large amount of ripple in double-frequency outputs will emerge in input currents at dc side due to the pulsating output power in a single-phase DC-AC power conversion system. We studied a current-source type single-stage single-phase inverter. Based on the power switch multiplexing technique, this topology can realize both DC-to-AC power conversion as well as low-frequency input current ripple reduction with a lower number of switches. The equivalences of low-frequency ripple propagation and circuit model are firstly analyzed between this single-stage circuit and a conventional two-stage one. A control strategy is presented, which is capable of controlling the port performances of both the DC input and ac output. Then the similarities on device rating are revealed by a contrast study. Finally, the controller effectiveness and performance analysis validity are verified by simulations and experiments.