Enhanced Hybrid PWM for the Closed-Loop Control of Permanent Magnet Synchronous Motor Drives

Integrating asynchronous pulsewidth modulation (PWM) and synchronous optimal PWM (SOPWM) in a hybrid PWM scheme has proven to be an effective modulation strategy for ac motor drives operating over a wide speed range. However, hybrid PWM is rarely used in permanent magnet synchronous motor (PMSM) drives in traction applications due to the noise sensitivity issues associated with SOPWM and the complex PWM transition schemes. To overcome these drawbacks, this article introduces an enhanced hybrid PWM technique suitable for integration with the well-established field-oriented control (FOC) strategy. The proposed technique relies on an innovative robust SOPWM and simple smooth PWM transition schemes to improve the robustness of hybrid PWM against noise in the control loop introduced by the measured currents and rotor position. Experimental results are provided to validate the effectiveness of the proposed hybrid PWM technique used in the closed-loop control of a PMSM drive.