Optimization of Flying Capacitor Voltage for Predictive Control of Open-Winding Permanent Magnet Synchronous Motor Drive

This paper proposes an enhanced configuration for an open-winding permanent magnet synchronous motor, utilizing a combination of a battery and a floating capacitor to establish two distinct DC link voltages. The optimization focuses on the ratio between these voltages, with the floating capacitor dynamically adjusting based on the battery voltage. The voltage of the floating capacitor is regulated by a model predictive control strategy to maintain its optimal value. Each side of the open-winding permanent magnet motor is powered by a two-level voltage source inverter. By leveraging isolated DC voltages, a maximum of 49 different voltage vectors can be applied to control motor operation. A model predictive control strategy determines the optimal voltage vector for each switching period, aiming to minimize harmonic distortion while improving performance. Simulation results indicate that the refined voltage ratio, facilitated by the floating capacitor, further reduces the total harmonic distortion factor of the stator current compared to alternative configurations.