Development of a novel power apparatus to make up for voltage dips and momentary interruptions based on quick reversible operation of a power converter

Abstract

Along with wide and deep dissemination of electronics application to our modern society voltage dips and momentary interruptions mainly due to lightning on overhead transmission lines has become to disturb normal operation of loads. UPS, which is mostly employed to protect sensitive loads from them, has such limitations that it dissipates not less energy in running operation because currents flow through two converters in series, that it is poor to feed electric motors which occupy main loads in industrial plants and that it costs high to be applied in common. UPS can be regarded not as omnipotent against voltage dips.
We have developed a novel power apparatus termed QBS (Quick Backup System) to supplement above drawbacks in UPS, employing one reversible ac/dc converter and one high-speed switch. Normally QBS supplies power directly from a commercial network to critical loads while the reversible converter interconnects with it to charge the battery. When the critical bus voltage deviates from the tolerance range QBS disconnects the high-speed switch and continues to feed the critical loads in UPS mode. The whole power transition is completed within 2ms. This paper presents constitutional technologies developed to realize QBS and obtained experimental data in the field demonstration test of a 100kVA QBS.