Hysteresis Current Controller With Fixed Switching Frequency and Phase for Interleaved Converters

The changing switching frequency of the hysteresis current controlled (HCC) converter leads to difficult filter configuration and wide electromagnetic impact. Random current ripples from parallel HCC converters cannot be interleaved, and this limits the application in high-power conditions. To improve the EMI characteristics and reduce the filtering difficulty, this article proposes a double-loop hysteresis current controller to fix the switching frequency and phase. Specifically, the inner loop accurately fixes the switching frequency on the order of switching cycles through feeding forward the disturbances from the grid and the reference. The outer loop detects and fixes the switching phase by adjusting reference frequency. The double-loop structure is independent of the power control and takes effect by adjusting the hysteresis band width. Furthermore, by shifting the switching phase between parallel hysteresis current control (HCC) converters, the ripple of total current can be cancelled, which enables multiple interleaving of HCC converters. The improved HCC converter retains excellent dynamic and antidisturbance performance, laying the foundation for the usage of HCC in high-power condition. Finally, experimental results are provided to verify the effectiveness of the proposed method. Dynamic response and antidisturbance performance of the proposed HCC method are also tested. This article is accompanied by a video file demonstrating the effect of ripples interleaving of two parallel HCC converters.