Zero Voltage Vector Extended Dual-Carrier PWM for Common-Mode Voltage Suppression

The voltage-source inverter (VSI)-based AC-DC-AC drive employing pulse width modulation (PWM) is extensively applied in permanent magnet synchronous motor (PMSM) systems due to its superior speed regulation capabilities and ease of digital control implementation. Nevertheless, the high-frequency switching operations of inverter semiconductor devices introduce large-amplitude, high-frequency common-mode voltages (CMV) within the drive system. These voltages can lead to motor insulation degradation, common-mode electromagnetic interference (EMI), and bearing damage, thereby significantly reducing the operational lifespan of the motor. To address these issues, this study proposes a CMV suppression modulation strategy based on the use of equivalent zero vectors. By applying the equivalent zero vector approach, the proposed method effectively reduces the CMV associated with the extended double carrier PWM strategy, particularly in low modulation regions.