| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect open phase such as breaking in a three-phase motor regardless of states before start and during drive.SOLUTION: Before starting the three-phase motor, an operation of supplying current to a phase and absorbing current from the other two phases is performed for each phase and the presence or absence of abnormality is determined by determining whether direct current flows from an inverter circuit to a DC/DC conversion circuit for each operation (S2, S3). After starting, the above described direct current is continuously detected when drive current is supplied from the inverter circuit to the motor so as to rotate the three-phase motor and the presence and absence of the abnormality is determined by determining the number of saw tooth wave like peak which appears six in one rotational period of the motor not in an open phase state and reduces to two during the open phase (S5, S6). When the abnormality is determined in S6, the drive of the motor is stopped once and an abnormality notification is performed by confirming phase in the open phase state by performing a breakage detection processing same as in S2 (S7 to S9, S12). |
