Analysis of CM EMI reduction with zero CM modulation scheme utilizing paralleled inverters

Common mode voltage is a key issue in variable speed AC motor drive, but conventional single three-phase voltage source inverter cannot effectively suppress the common mode voltage. The system of paralleled voltage source inverters is more flexible and can be utilized to implement novel modulation schemes to reduce the common mode component. This paper focuses on three modulation schemes which have different performance in common mode voltage suppression and fair comparison of electromagnetic interference is also implemented. Experimental results are provided to show the advantage of proposed method in common mode electromagnetic interference noise reduction and DC side electromagnetic interference filter design.