AIR CONDITIONING APPARATUS

摘要

An air conditioning apparatus is provided with an excess voltage cutoff section for cutting off application of an excess voltage to a power supply section of an upper arm control circuit or that of a lower arm control circuit when an excess voltage is applied to the other arm control circuit from an upper arm element group or a lower arm switching element group. The excess voltage cutoff section separates the switching power supply sections one from the other. Thus, a problem of having breakage in a chain reaction when one of the switching groups is broken and being in DC voltage short-circuit mode which cannot be stopped by a control circuit is solved.