Common-mode voltage suppression for traction drive systems based on carrier phase shift control

To suppress the common mode voltage generated by the traction system due to inverter pulse-width modulation (PWM) and to reduce electrical corrosion of the bearings and electromagnetic compatibility (EMC) interference, this paper proposes a strategy for suppressing common mode voltage based on dynamic carrier phase shift. In situations where multiple inverters share a common DC bus without a synchronization line in the train, the dynamic mean of the neutral-point voltage is used as the real-time adjustment reference. By adjusting the PWM carrier period, the dynamic phase shift control of the inverters is achieved, resulting in phase cancellation of the common mode voltage on the DC side of the traction system. This significantly mitigates the common mode voltage and it adverse effects. Hardware-in-loop simulation and high-power locomotive tests demonstrate that this strategy reduces peak common mode voltage by 36%, ensuring that the fluctuation amplitude meets the theoretical limits without requiring additional hardware. It remains compatible with existing modulation solutions.