Robust current control method with a disturbance voltage observer for a voltage source PWM inverter

In recent years, the voltage source Pulse Width Modulated (PWM) inverter has been used as a power supply in the field of motor control, UPS (Uninterruptible Power Supply), power conditioners, and so on. Current tracking control for the PWM inverter is very important, since current control ability affects the control performance of the plant. In this paper, the robust current control method, with the disturbance voltage observer as the voltage source PWM inverter, is presented; current is controlled to be exactly equal to the reference current under variations of load parameters and operating conditions. Also, the influence of estimation error is restrained by a time-varying feedback gain based on Lyapunov”s direct method. The feedback gain is calculated online to ensure the system's stability with various disturbances.