This paper proposes a cascaded nonlinear PI controller for three-phase voltage source PWM rectifier, which is based on its model in synchronous reference frame.

By making changes of reference voltage phase diagrams of load, this method can enlarge the compensation range and decrease the energy output of DVR.

The low-voltage driving circuit is adopted to drive a piezoelectric ceramic phase shifter to shift the phase of the reference beam, so as to make the instrument lighter, smaller and cheaper.