0.4 Research on common mode voltage cancellation strategy for four-module motor driven by parallel balanced inverter

In response to the issues of common mode voltage and the resultant common mode currents and leakage currents in PWM motor drive systems, this paper proposes a topology using a parallel balanced inverter to drive a four-module motor. Traditional three-phase inverters, with an odd number of bridge arms, inherently struggle to eliminate common mode voltage. By employing a balanced inverter, the proposed method extends the degrees of freedom, achieving internal group common mode voltage cancellation. Furthermore, replacing the conventional three-phase motor with a four-module motor and altering the stator winding connections, combined with a carrier phaseshifting modulation strategy, allows the system to cancel common mode voltages using a parallel balanced inverter. To verify the efficacy of the proposed solution, a simulation of a parallel balanced inverter driving a four-module motor system was constructed and compared with a traditional three-phase inverter system. The simulation results demonstrate that the new topology effectively suppresses system-conducted interference, thereby improving the system's electromagnetic interference performance.