Control of Half-Bridge Resonant PWM Converter for Electromagnetic Vibratory Actuator

The subject of this paper is the control system of the half-bridge resonant pulse width modulation (PWM) converter for electromagnetic vibratory actuator (EVA). Although the half-bridge converter topology has been analyzed in the literature, mainly silicon controlled rectifiers (SCRs) have been employed as semiconductor switches, whereby the use of transistors would offer some advantages regarding effectiveness of control. Therefore, the main objective of this paper is to replace SCRs with transistors in the half-bridge resonant topology, and to develop a suitable control system for amplitude-frequency control of EVA. The switching instants of transistors in the half-bridge converter are determined in order to accomplish resonant operating condition of EVA, thus ensuring maximum amplitude of vibrations with minimum energy consumption. The amplitude of EVA vibrations and half-bridge converter switching instants are estimated by employing a state observer, resulting in a high performance feedback control loop. The effectiveness of the proposed control system is verified by computer simulations and the results are thoroughly discussed.