A Novel DC-link Midpoint Switching Scheme for Common-Mode Voltage Mitigation in 3-Phase 2-Level VSI

To address the most vulnerable Electro Magnetic Interference (EMI) issues in electrical drives, it is proposed to device a simple but effective solution to mitigate common-mode voltages which are source of EMI issues. In this regard a new 3-phase 2-level inverter topology with three DC link capacitors is proposed. The idea behind the proposed method and topology is that by suitably switching the DC-bus midpoint during every switching state of the voltage vector, zero common mode voltage can be achieved in every active switching state. While comparing with various CMV reduction methods from literature, this method is simple to implement and completely eliminates common mode voltage without any additional switching losses.