Electric power conversion device, compressor motor with the device, and air conditioner with the motor

摘要

The device is provided with an electric power conversion circuit (3) including switching elements (9) for converting a DC electric power to an AC electric power, a load (4) connected to an output side of the electric power conversion circuit (3), means (6) for detecting a current flowing through a DC side in the electric power conversion circuit (3), a voltage command value preparing means for controlling the operation of the switching elements (9) in the electric power conversion circuit (3) and a wire breaking detecting means (8). The wire breaking detection means (8) judges a wire breaking in the load (4) or an abnormality of any of the switching elements (9) in the electric power conversion circuit (3) by making use of a DC current detection value in a period when a current of maximum voltage phase or of voltage minimum phase of the electric power conversion circuit (3) is flowing in a DC current.