Improvised SVPWM Strategies for an Enhanced Performance for a Four-Level Open-End Winding Induction Motor Drive

Abstract

—Afour-level open-endwindinginductionmotor drive (OEWIMD) is obtained when an induction motor with open windings is fed from either side with two two-level 3-Ph voltage-source inverters (VSIs) with unequal dc-link voltages, which are in the ratio of 2:1. This drive princi pally suffers from two problems namely: the circulation of zero sequence current in motor phases and overcharging of the lower dc-link capacitor by its counterpart with higher dc-link voltage. It has been reported earlier, that the decou pled space vector pulse width modulation (SVPWM) control strategies avoid both of these problems. This paper pro posesanimprovisedSVPWMschemethatachievesabetter harmonic performance compared to the decoupled SVPWM scheme without altering either the power circuit configu ration or the voltage ratings of the devices. The proposed PWM strategy clamps the inverter with lower dc-link volt age with an active state, while the other inverter is switched around it. It has been shown that the proposed SVPWM schemeresultsinanoverallreductionoflossesforthedrive system while resulting in a considerably lower dv/dt com pared to the decoupled SVPWM schemes. The four-level OEWIMDemploying the proposed SVPWMschemeissimu lated and is validated with experimental results.