Angle Synchronized PWM to Enable High Degree of Overmodulation for Increased E-Drive Performance

Abstract:
This paper presents a PWM modulation method to be applied in the lower speed range of the field weakening region of an electric drive train system as an alternative to the six-step mode. The method uses existing PWM methods and adjusts the carrier frequency so that an angle synchronous and deter-ministic switching pattern is created. The proposed method can be activated starting from the rated operating point and thus maximizes the use of overmodulation, which is typically limited in asynchronous PWM methods. The proposed method leads to increased voltage utilization, efficiency, and performance in this area.