Traditional AC voltage regulator usedrnservo-motor position regulation or thyristor phase controlled method which hadrnlow dynamic response speed or large amount of harmonic components. However,rnthese drawbacks can be overcome by using Pulse Width Modulation chopperrntechniques in AC voltage regulation. Buck-Boost Chopper type AC voltagernregulator, derived from the DC chopper modulated method, is a kind of directrnAC-AC voltage converter and has many advantages: such as fast response speed,rnlow harmonics and high power factor. It adopts high switching frequency ACrnchopper techniques and can do wide range step less AC voltage regulation. Thernsteady-state equivalent circuit of the Buck-Boost chopper type AC voltagernregulator, as well as the theoretical analysis method of the input power factorrnand the output voltage is presented in this paper. In addition, in order tornsolve the problems caused by the sags or swells of the input voltage, thernoutput voltage controller is designed. The proposed voltage controller usesrnoutput peak voltage as feedback signal and adopts PI control strategy tornregulate the output voltage. Digital simulation results coincide with therntheoretical analysis and show that the Buck-Boost chopper type voltagernregulator has a unit input power factor and that the designed voltagerncontroller can stabilize the output voltage with fast dynamic speed when inputrnvoltage fluctuations occur.