BACKFLOW PREVENTION DEVICE, POWER CONVERTER, MOTOR DRIVE DEVICE, AND REFRIGERATING AND AIR-CONDITIONING DEVICE

摘要

A backflow preventing device includes a backflow preventing element 5 that is connected between a power supply 1 and a load 9 and that prevents electric current from flowing backward from the load 9 side toward the power supply 1 side, a commutating device 7 that performs a commutation operation for causing the electric current to flow to a commutation path connected in parallel with the backflow preventing element 5, and a controller 100 that sets a time for performing the commutation operation and causes the commutating device 7 to perform the commutation operation based on the set time. The backflow preventing device has a plurality of the commutation paths and has, for example, elements with small current-carrying capacities disposed in the commutation paths to achieve cost reduction and to cope with, for example, failures, thereby allowing for enhanced reliability for reducing recovery electric current.