| 摘要 |
PROBLEM TO BE SOLVED: To prevent overloading on an inverter at the time of motor lock, by limiting a torque command value if detected motor revolution speed is smaller than a prescribed value and estimated element jointed part temperature exceeds a prescribed value, and limiting the current of respective switching elements according to it. SOLUTION: If motor revolution speed is smaller than a prescribed value and a torque command value |Tr*| is larger than continuously operable torque, it is discriminated that a motor is in locking or a minimum revolution speed condition. The estimated values of the fin temperature for each of switching elements T1 to T6 and jointed part temperature are obtained from elapsed time after these conditions have been made, three-phase output current, and actually measured temperature values Ts of the respective switching elements T1 to T6 by a thermistor 6. A torque limit value is obtained by table lookup processing from a torque limit value map for preset jointed part temperature, and current of the switching elements T1 to T6 during energization is controlled according to a torque command Tr* restricted so that it may be the limit value or less. |
