Static transfer switch device, power supply apparatus using the switch device and switching method thereof

摘要

Disclosed is a static transfer switch with a modified structure that can selectively supply power from power sources to a load stably and continuously, a power supplying apparatus employing the same, and a switching method thereof. The present invention includes mechanical/electrical contact point switches in parallel to semiconductor switches, and minimizes operation time of the semiconductor switches by turning on/off the mechanical or electrical contact point switches together when the semiconductor switches are turned on/off to reduce a failure rate of the semiconductor switch. Also, the static transfer switch makes a switching unit electrically/mechanically separable from a power source with failure to switch a power supply path and thereby prevent superposition caused by the switching unit. This prevents a problem caused when electrical or mechanical contact point switches simply in parallel, that is, a problem that power sources are turned on simultaneously when the power supply paths are switched.