SIMPLE STRUCTURE MULTILEVEL INVERTER USEFUL FOR AC MOTOR DRIVES

ABSTRACT In this paper, a new simplified configuration for a multilevel PWM inverter and its control strategy is proposed. The proposed configuration consists of an auxiliary circuit with four switching devices, and a single full-bridge inverter. For medium power applications, the new circuit design, in which the number of switching devices is reduced, offers characteristics similar to conventional NPC inverters. The control method is based on closed loop regulation of the instantaneous line-to-line output voltages. The proposed scheme is simple, has fast response, and is effective for reducing the size of the DC-link capacitors. The performance of the system is verified by computer simulation and by practical experience

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