Suppressing common-mode conducted EMI generated by PWM drive systems using a dual-bridge inverter

This paper presents a dual-bridge inverter approach to reducing the conducted electromagnetic interference (EMI) generated by pulse-width modulated (PWM) inverters in adjustable speed drive (ASD) motor systems. The novel dual-bridge inverter (DBI) is controlled to generate balanced excitation of induction motors under PWM ASD operation. Thus, the inherently generated common-mode voltage is eliminated and the resulting common-mode conducted EMI is significantly reduced. Theoretical analysis and experimental results are presented to verify this concept.