Research on motor sensorless control strategy with adaptive delay compensation

The high voltage and current of the traction drive system in rail transit are limited by the system losses and heat dissipation capacity of the inverter. The low switching frequency of IGBT (Insulate-Gate Bipolar Transistor) reduces the performance of the motor speed control vector control system due to the system delay caused by this. After the traction motor runs to the high-speed zone, the carrier ratio decreases significantly, making it more likely to cause torque ripple in the system. In response to this issue, this article proposes an improved sensorless control algorithm based on time delay compensation, which effectively eliminates unstable phenomena such as motor current oscillation and speed pulsation caused by delay in the system at medium and high speeds, and achieves stable control in the low-speed to high-speed full speed range. Finally, the effectiveness of the delay compensation algorithm was verified on a large traction motor towing platform.