Design of Variable Pole Phase Induction Motor Drive With Hybrid Four Quadrant Switch Configuration

In electric traction applications, researchers are employing pole phase modulation (PPM) based multiphase induction machines (MIM) to achieve a broader range of speed and torque, allowing for dynamic switching between the various pole phase configurations. The existing literature studies have concentrated more on various inverter topologies for variable pole phase-based induction machines (VPIM). Here, the torque ripple and dc bus voltage utilization (DBVU) issues are tackled with multiple four-quadrant switches along with 3-ϕ SVPWM technology. However, the design of the VPIM drive system w.r.t the converter and machine is crucial, which is not explored in previous studies. This article aims to bridge this gap by describing design considerations of the inverter configuration as well as the motor for VPIM drives. A simple 2-level 9-ϕ inverter with a hybrid four-quadrant switch (HFQS) is proposed for VPIM with phase grouping and isolated neutral techniques. This HFQS is realized with one controllable switch and six power diodes with snubber protection to limit the voltage surges during the transitions from one pole to another pole combination. The design considerations of the dc bus, switch selection for the 9-ϕ inverter, and design of a proposed HFQS are presented in detail. It further presents complete switching loss analysis, conduction loss analysis, and overall inverter as well as motor efficiency. The 3-ϕ carrier-based SVPWM ensures better DBVU, and phase-shifted carriers give the enhanced torque ripple in the high pole mode of a 9-ϕ VPIM drive. The proposed inverter design for a 9-ϕ VPIM has been implemented and validated with Maxwell 2-D, along with Simplorer, and the laboratory prototype of a 5 hp motor.