Novel current control strategy for maximum tracking operation under saturated voltage condition

A synchronous frame proportional integral (PI) current controller has been widely used in AC electric machine drive system. This current controller should contain an anti-windup scheme to prevent the integral term in the controller from blowing up. This paper addresses the reference tracking performance of current controller with the anti-windup when the output of the PWM inverter is saturated due to limitation of DC bus voltage. The problem of the conventional PI current controller caused by the inverter saturation is identified in a viewpoint of the reference tracking, and a novel current control strategy is proposed. The proposed current control strategy shows the better tracking performance without blowing up the integral term in controller even in the case of inverter saturation. Experimental and computer simulation results are shown to verify the effectiveness of the proposed strategy.