Abstract
This paper proposes a space vector modulation (SVM)-based common-mode (CM) currents reduction method of an H8 inverter for permanent magnet synchronous motor (PMSM) drives. There are power quality issues in the PMSM drive systems, such as current distortions and CM electromagnetic interference (EMI) due to the fast-switching operation of the inverter. These issues are related to CM voltage (CMV) and CM current (CMC). Although several studies have been conducted to reduce the CMV and CMC, some CMV variations and CMCs are still generated in the real implementation. Unlike conventional methods, the proposed method selects the voltage vectors with similar CMV levels and arranges them considering the series-connected switch operation of the H8 inverter in a voltage vector modulation sequence. At a low modulation index (MI), the proposed method completely restricts the CMV variations into six times. At high MI, the proposed method synthesizes the reference voltage vector differently, depending on the position of the reference vector, to reduce both current distortions and CMCs. The validity of the proposed method is verified through simulations and experimental results.