Adaptive PWM Modulation for an Increased Energy Efficiency of Industrial Drives

Switching losses in inverters for industrial electric drives have a noticeable impact on their energy consumption and lifetime. In order to fulfill the accuracy requirements of electric drives for production equipment, a high switching frequency is typically used. This results in high switching losses which are proportional to the switching frequency. However, a high accuracy is not always required. Therefore, a method for adapting the switching frequency of the drive inverter during runtime when high accuracy is not required is presented in this paper. The method includes the identification of operating states of the machine tool, automatic calculation of the controller parameters and strategies for changing the PWM frequency during runtime. Experimental results validate this novel approach.