New generalized multilevel current-source PWM inverter with no-isolated switching devices

Abstract

The paper proposes a generalized circuit configuration of a new multilevel current-source inverter (CSI) with no-isolated switching devices. In this new multilevel inverter topology, all of the power-switches in the inverter are connected on a common-potential level. Hence, all of the power switches only need a single gate drive power supply without using isolated power supplies or conventional bootstrap techniques. This key feature is still valid even if the number of the power switches increases due to the higher number of the output current waveform levels. As a result, complexity of the gate drive circuit can be remarkably moderated. In addition, the multilevel CSI circuit is capable to operate at high switching frequency if required, because all of the power switches are connected on the common potential level. Five-level PWM inverter configuration, including its chopper circuit as DC current-power source circuits using small input inductors, is verified through computer simulations and experimental tests. The results show feasibility of the proposed topology with reducing the circuit complexity and physical size of the multilevel CSIs.