Automatic voltage regulator with fast dynamic speed

Abstract

A novel automatic voltage regulator is proposed and analysed. The power circuit is made up of a pulse-width modulated (PWM) buck-boost AC chopper which uses only two standard switch modules. In the AC chopper, the commutation scheme allows dead-time to avoid current spikes from switching and at the same time establishes a current path in the inductor to avoid voltage spikes. The AC chopper uses regenerative DC snubbers attached directly to power semiconductor modules to absorb energy stored in stray line inductances. These DC snubbers enhance the conversion efficiency and feature a very simple structure consisting only of a capacitor. A fast peak voltage detector for fast output voltage control is also proposed. It is shown, via experimental results, that the proposed scheme gives good dynamic and steady-state performances for a high-quality output voltage.