Jun-Hyeok Park, Hyung-Woo Lee, and Kyo-Beum Lee "APOD PWM Based Method to Suppress Zero- Sequence Circulating Current in Parallel Three-Level NPC Inverters under Interleaved Operation," in Proc. ECCE Conf., 2022. > Paper

This paper presents a method to reduce highfrequency (HF) and low-frequency (LF) zero-sequence circulating current (ZSCC) simultaneously under the interleaved operating conditions. Recently, a parallel operation of inverters has been widely used to obtain high power ratings. A parallel operation 

degrades the quality of the output current because the current harmonics of each inverter overlap. While the interleaved operation prevents the 

increment of the current harmonics, HFZSCC generated by intentional carrier phase difference is inevitable. The carrier modulation method using the 

alternative phase opposition disposition pulse width modulation (APOD PWM) is effective to reduce ZSCC generated by the interleaved PWM. In this 

paper, both the double-reference PWM (DRPWM) method and the optimized zero-sequence voltage (ZSV) injection method based on APOD PWM are used to reduce HF- and LFZSCC respectively. The feasibility and effectiveness of the proposed method are verified by simulations and experimental

results.