ROBUST CURRENT CONTROL METHOD WITH A DISTURBANCE VOLTAGE OBSERVER FORA VOLTAGE-SOURCE PWM INVERTER

In recent years, the voltage source Pulse Width Modulated (PWM) invert er 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 curren t control ability affects the control performance of the plant. In thi s paper, the robust current control method, with the disturbance volta ge observer as the voltage source PWM inverter, is presented; current is controlled to be exactly equal to the reference current under varia tions of load parameters and operating conditions. Also, the influence of estimation error is restrained by a time-varying feedback gain bas ed on Lyapunov's direct method. The feedback gain is calculated online to ensure the system's stability with various disturbances.