Using DPWM method to improve system efficiency of the machine drive system

Efficiency is one of the important indicators of motor drive systems. The PWM method has a direct impact on the efficiency of the motor drive system. Commonly used PWM methods are CPWM and DPWM. The DPWM method can reduce the number of inverter switching and improve the efficiency of the inverter. However, the harmonic content of the current changes and the motor efficiency decreases. This paper studies this problem and proposes a method to improve system efficiency by switching CPWM and DPWM modes. First, the two PWM methods are compared and analyzed, and the interval with a large modulation ratio is obtained. The conclusion that the DPWM can improve the system efficiency. Then, with the highest system efficiency as the goal, determine the applicable range of the CPWM and DPWM methods. Switching between the two PWM methods is implemented by the program. Finally, the experimental bench was set up and the proposed method was experimentally verified. The experimental results show that the efficiency of the high-speed zone system is improved by 0.3-0.5% using the proposed method.