Patent ID: 8305020

Claim:
An electric power conversion device comprising: an electric power conversion circuit including switching elements for converting a DC electric power to an AC electric power, a load connected to an output side of the electric power conversion circuit, a DC current detecting means for detecting a current flowing through a DC side in the electric power conversion circuit, and a control circuit for controlling the switching elements in the electric power conversion circuit, characterized by further comprising a wire breaking detecting means that judges a wire breaking in the load or an abnormality of any of the switching elements in the electric power conversion circuit by making use of a value of DC current detected by the DC current detecting means during a time when a first current flows in a voltage maximum phase, which has the longest turn-on term in a duty cycle for upper arm switching elements of the electric power conversion circuit, which first current flows through the DC side in the electric power conversion circuit, or during a time when a second current flows in a voltage minimum phase, which has the shortest turn-on term in the duty cycle for the upper arm switching elements, which second current flows through the DC side in the electric power conversion circuit.