Patent ID: 6995481
Filing Date: 2006-02-07
Classification: H02M

Abstract:
1. A power control device for connection to AC mains electric power supply having a power supply frequency and an AC load, comprising: a bi-directional electric power switch capable of being switched at a switching frequency that is a multiple of the power supply frequency, connected in series between the AC mains power supply and the load and comprising two switching elements connected in series and oriented in opposite polarities, each switching element having an “off” condition in which the switching element substantially blocks a flow of current in one direction, a bi-directional electric circulating switch capable of being switched at the switching frequency, for parallel connection to the load, comprising two switching elements connected in series and oriented in opposite polarities, each switching element having an “off” condition in which the switching element substantially blocks a flow of current in one direction; and a control module for controlling the switches, comprising whereby the circulating switch is operative to supply a circulating current to the load during intervals when the mains power supply to the load is interrupted.