Motor drive device having short-circuit determination unit of DC link capacitor

摘要

A motor drive apparatus includes a converter which converts AC power into DC power and outputs it to a DC link, an inverter which converts the DC power of the DC link into AC power for driving a motor, DC link capacitors connected in series with each other, resistors connected in parallel with the DC link capacitors and connected in series with each other, a DC link voltage detection unit, a current-carrying element which is connected between one of connection points connecting the DC link capacitors to each other and one of connection points connecting the resistors to each other, and carries a current when the applied voltage is higher than a predetermined value, and a short-circuit judgment unit which judges that at least one of the DC link capacitors has shorted when the DC link voltage value is larger than an upper limit or smaller than a lower limit.