Control of a three-phase PWM rectifier using estimated AC-side and DC-side voltages

A new control method of a pulsewidth modulation (PWM) rectifier without measuring AC- and DC-side voltages is proposed. As information about these voltages is necessary for the controller, all required voltage values are estimated from the measured line currents and the calculated values of the input reactor voltage during switching of the rectifier circuit. The input reactor voltage can be obtained by using a differentiator that produces the derivative of the line current or by detecting the voltage induced in a secondary winding wound on the input reactor. The secondary winding creates the electric isolation between the main circuit and the controller. The proposed method is verified by experiment. This paper describes the estimation method, gives the configuration of the controller, and discusses steady-state and transient performances of the rectifier