PWM AC voltage regulator includes PWM single-phase AC voltage regulator and three-phase AC voltage regulator, as an AC voltage-regulating controller, it adopts an integrated design combining PWM AC controller and load-matching transformer and realizes adjustable output voltage magnitude at the secondary side of the load-matching transformer by the PWM control mode of PWM AC controller at the primary side of the load-matching transformer. Because its power factor is higher than 0.98 and the total harmonic distortion of current THDI is less than 6%, the conversion efficiency of the power supply is more than 0.96. Under the condition that no any power factor compensation and harmonic wave absorption apparatus is attached, the power factor and harmonic wave have met the standard requirements of the State Grid. Characterized by advantages such as constant voltage, constant current, constant power closed-loop control and multiple given control signal selections.