Suppressing Zero-Sequence Circulating Current of Modular Interleaved Three-Phase Converters Using Carrier Phase Shift PWM

Zero-sequence circulating current (ZSCC) has been a major concern for the operation of paralleled converters. Existing ZSCC reduction methods in the literature either suffer poor performances or are too complicated for modular implementation in an arbitrary number of interleaved converters. This paper investigates the application of interleaved carrier phase-shift (ICPS) pulse-width modulation (PWM) in modular interleaved converter system for ZSCC peak value reduction. The generalized study based on the derived ZSCC analytical expression reveals that the ICPS PWM can achieve superior ZSCC peak value reduction performance regardless the number of interleaved converters. Moreover, the impacts of ICPS PWM on the output voltage and current quality are also analyzed based on double Fourier integral. Compared with the conventional interleaved sinusoidal PWM (ISPWM), the output quality with the ICPS PWM can be comparable or even better. Simulation and experimental results show good agreement with the theoretical analysis, verifying the performance of the ICPS PWM.