Patent ID: 6747882
Filing Date: 2004-06-08
Classification: H02M,H02P

Abstract:
A power conversion device comprising:a power converter which controls a motor in variable speed control; a first control circuit which outputs a first control signal to control the power converter; a second control circuit which outputs a second control signal to control the power converter; a first detector which detects a state of the power converter and outputs a first detection signal to the first control circuit; a second detector which detects a state of the power converter and outputs a second detection signal to the second control circuit; a switch which receives the first control signal and the second control signal and outputs one of the first control signal and the second control signal to the power converter; and a selection circuit which outputs a changeover selection signal to the switch for outputting the second control signal instead of the first control signal, when the switch has outputted the first control signal and the first control circuit fails, wherein at least one of the first control circuit and the second control circuit outputs a restoring signal to the power converter to return to a previous state of the power converter when the power converter fails.