A novel PWM inverter switching strategy for a dual two-level inverter fed open-end winding induction motor drive

A dual two-level inverter fed open-end winding induction motor drive is proposed in this paper. A total of 64 voltage space phasor combinations are possible in this scheme as each inverter produces eight voltage space phasors. The proposed scheme produces voltage space phasor locations similar to that of a 3-level inverter. In a 3-level inverter the series connected DC link capacitors carry the load current. This results in a fluctuating voltage space phasors, which is undesirable. Also, a 3-level inverter requires a bulky DC link capacitor. In the proposed scheme the DC link capacitor carries only the ripple current and hence the voltage space phasor fluctuations are absent. A novel PWM switching strategy aimed to suppress the zero sequence currents is also proposed in this paper, without the need for harmonic filters and isolation transformers.