Zero state common mode voltage control in motor drives through inverter topology

Wide bandgap devices are believed to replace Si devices in next generation drives, due to their superior characteristics such as low loss, high speed, and high temperature operating capabilities. However, the adoption of these devices also brings up new challenges on common mode voltage related issues, such as ground leakage current, common mode EMI emission, and bearing current. As a potential solution, this paper proposes a novel method for controlling the common mode voltage of motor drives during zero switching states by gating the two extra switches between DC bus and inverter in a regulated manner. The relationship between gating timing and common mode voltage amplitude during zero states are particularly investigated and quantified for the proposed approach.