An electric motor drive device with a failure detection circuit and a failure detection method for an electric motor drive device having a failure detection circuit

摘要

An electric motor drive apparatus having a failure detection circuit (1) includes: a bridge circuit (200) that drives an electric motor (100); a PWM control circuit (502) that generates voltage instructions for driving the electric motor (100); a PWM signal generation circuit (503) that generates a PWM signal; a DC detection circuit (400) that detects DC current of the bridge circuit (200); a phase current calculation circuit (501) that calculates output phase current of the bridge circuit (200) based on the DC current and the PWM signal; and a failure detection circuit (600) that detects the failure of the DC detection circuit (400). The failure detection circuit (600) determines the failure of the DC detection circuit (400) from the DC detection values in a zero voltage vector period in which the high potential side arms (21) of the bridge circuit (200) are all ON, and in a zero voltage vector period in which the low potential side arms (22) are all ON are.