Motor drive unit with short-circuit rating unit for capacitor of a DC link unit

摘要

A motor driving apparatus 1 has a PWM converter 11 configured to convert AC power from an AC power supply 2 into DC power by PWM control, and outputs the DC power, a DC link unit 12 having capacitors located on the DC output side of the PWM converter 11 are provided and connected in series with each other; an inverter 13 connected to the DC link unit 12 and configured to convert the DC power of the DC link unit 12 into AC power for driving a motor 3 and output the AC power, a DC link voltage detection unit 16, a power supply voltage detection unit 17, a short circuit judgment unit 14 judges that at least one of the capacitors has been short-circuited when the DC link voltage is smaller than the peak value of the power supply voltage, and a turn-off unit 15 configured to turn off the AC current from the AC power supply 2 to the PWM converter 11 when the short-circuit judgment unit 14 judges in that at least one of the capacitors has been short-circuited.