This paper presents a novel single-phase ac voltage regulator based on buck-boost converter topology. The regulator circuit has a simple structure. It does not require a coupling transformer, uses only two bidirectional active switches and includes only one inductor and one capacitor. The proposed regulator operates through a closed loop control system, where the controller is supported by a control law depending on the instantaneous values of the regulator’s real input and the desired output voltages. The control law provides an efficient pulse width modulation (PWM) switching duty ratio for the desired output voltage when the input voltage has fast fluctuations and the output load is changed. Simulation studies have been done for the proposed ac voltage regulator in MATLAB-Simulink. The simulation results have shown that the proposed topology is capable of and efficient for both bucking and boosting the input ac voltage to generate a high quality output voltage with a low total harmonic distortion (THD) for different input voltage and load conditions.

Keywords: Alternating current voltage regulator, Buck-boost converter, Pulse-width modulation (PWM), Total harmonic distortion (THD)