Energy Efficiency Improvement in a Six-Phase Induction Motor Drive Using Fixed Switching Frequency Predictive Control and Optimized Virtual Voltage Vectors

Six-phase induction motor (۶PIM) drives face fundamental challenges in energy efficiency and switching frequency stability. Finite-control-set model predictive control (FCS-MPC) methods, despite their fast dynamic response, exhibit variable switching frequency, which leads to unpredictable switching losses, complex EMI filter design, and reduced overall efficiency. This paper presents an optimized predictive control strategy with virtual voltage vectors and fixed switching frequency (FS-VV-MPC) to improve energy efficiency and frequency stability in a six-phase induction motor drive. In the proposed method, a deadbeat controller analytically calculates the reference voltage in the aẞ subspace. Then, using ۱۲ virtual voltage vectors with inherent xy component cancellation, the reference voltage is synthesized. A seven-segment symmetrical sequence modulation mechanism stabilizes the switching frequency at a constant ۱۰ kHz. A multi-objective cost function with adaptive weighting factors establishes an optimal tradeoff among current tracking, harmonic suppression, and switching loss reduction. Simulation results on a ۵.۵ kW six-phase induction motor show that the proposed method increases efficiency to ۸۹.۶% (a ۰.۹% improvement over FCS-MPC) and reduces total losses by ۷.۴%. Moreover, the switching frequency is completely stable with a standard deviation of ۰.۱۵ kHz (۸۷.۵% improvement). A cost-benefit analysis demonstrates that the proposed method is economically fully justifiable, with a benefit-to-cost ratio of ۲.۴ and a payback period of ۱.۸ years.

کلیدواژه ها:

Predictive control ، fixed switching frequency ، virtual voltage vectors ، energy efficiency ، six-phase induction motor