Motor drive device capable of detecting a fault condition

摘要

This invention provides a motor drive device capable of detecting an ON fault of upper stage switching elements and lower stage switching elements for all of phases even when using a single current detection unit. A control unit (102) for outputting a PWM signal to a drive unit (101) includes an upper stage regeneration abnormality determination unit (103) and a lower stage regeneration abnormality unit (104). The upper stage regeneration abnormality unit (103) determines that ON fault occurred in at least one of lower stage switching elements (Q2, Q4, Q6) when current flowed to a current detection resistor (R) in an upper stage regeneration state in which upper stage switching elements (Q1, Q3, Q5) are all in an ON state. The lower stage regeneration abnormality unit (104) determines that ON fault occurred in at least one of upper stage switching elements (Q1, Q3, Q5) when current flowed to the current detection resistor (R) in a lower stage regeneration state in which lower stage switching elements (Q2, Q4, Q6) are all in the ON state.