Torque Ripple Reduction in Modular Drive of a Non-Sinusoidal, Asymmetric Six-Phase, Permanent Magnet Synchronous Motor with Double Stator Windings using Harmonic Current Injection Strategy

Multiphase permanent magnet synchronous motors (PMSMs) are widely adopted in high-power-density and high-efficiency applications, particularly where reliability is a critical design requirement. This paper presents a control strategy for an asymmetric six-phase PMSM with a dual-winding per-phase stator configuration, where each phase consists of two physically aligned and symmetrically distributed windings relative to the stator center to ensure enhanced drive reliability. The system employs a fully modular control and power architecture, with each winding pair in a phase supplied by an independent single-phase H-bridge inverter. To mitigate torque ripple caused by non-sinusoidal back-EMF waveforms, an optimized harmonic current injection technique is implemented alongside quasi-proportional resonant (QPR) current controllers for precise harmonic compensation. Additionally, under fault conditions (e.g., winding failure), a fault-tolerant control (FTC) algorithm is applied, focusing on the suppression of second-order harmonic torque oscillations to maintain stable operation. The proposed control methodologies are validated through detailed Simulink simulations and further supported by experimental results, confirming their effectiveness in improving performance and reliability.