A Fault Tolerant Multilevel Inverter for Improving the Performance of Pole-Phase Modulated Nine-Phase Induction Motor Drive

In this paper, a fault tolerant multiphase multi-level inverter (MPMLI) configuration is proposed based on dual inverter concept. This configuration helps to improve the performance of pole-phase modulated multi-phase induction motor (PPMMIM) drive in both normal and switch failure conditions. Compare to the existing multi-level inverter topologies for multi-phase induction motor (MIM) drives, the proposed MPMLI configuration requires less number of DC sources and power electronic devices. The proposed MPMLI configuration is able to sustain under various fault conditions, which can improves the reliability of the system. In addition, dc link utilization in low-pole mode is improved by using space vector pulse-width modulation. This MPMLI configuration produces a multilevel voltage profile across the effective phase in 3-phase 12-pole mode. By maintaining the V/f ratio constant, the proposed MPMLI fed MIM drive facilitates a wide range of load torque with half of the rated speed in fault condition. This advantage makes it suitable for traction and electric vehicle applications where reliability and wide range of torque-speed are the major concern. The performance of proposed MPMLI fed 5hp, 9-Φ PPMMIM drive is simulated by finite element method in ANSYS Maxwell 2-D and experimentally verified by laboratory prototype under normal and faulty condition