A Reduced Switch Count Hybrid Fifteen-level Inverter for an Open-End Winding Induction Motor (OEWIM) Drive

In this paper, a reduced switch count hybrid fifteen-level inverter topology for an OEWIM (Open-End Winding Induction Motor) drive is proposed. In this topology, one terminal of OEWIM is supported by a FC based hybrid 5-level inverter and other terminal is provided to a symmetrical 3-level inverter. The hybrid 5-level inverter is realized by cascading a 3-level flying capacitor inverter with capacitor fed H-bridge. The symmetrical 3-level inverter is obtained by cascade bond of two 2-level inverters with the same DC-link voltages. The combined effect of five-level hybrid and three-level symmetrical inverters generate fifteen distinct levels in the motor phase-voltage. In this proposed topology, a total of 74,088 space phasor combinations are accessible; hence using switching redundancies, the capacitor voltages can be retained at desired levels. The proposed topology requires only 36 switching devices, as compared to conventional topologies that require 84 switches and fully eliminates the requirement of clamping diodes, which are requisite in NPC inverter. It, also, requires only 6 capacitors unlike to 273 capacitors required in fifteen-level FC inverter and 3 DC power supply sources as compared to fifteen-level CHB inverter that requires 21 DC power supply sources. Simulation exercise is implemented to assess the performance of the considered scheme and outcomes are conferred.