| 摘要 |
PURPOSE:To protect the circuitry against breakdown due to overcurrent by lowering the output duty to an allowable limit when an overload is exerted onto a motor and an overcurrent flows through the circuitry. CONSTITUTION:A battery current detecting circuit 20 detects current when power is fed from a battery BT to a wheel drive motor M whereas a regenerative current detecting circuit 21 detects current to be fed back from the motor M to the battery BT during regenerative brake operation. Upper limit of output duty of driving pulse for the motor M, i.e., a duty limit value, is then decreased if the average current value is higher than an allowable current value otherwise it is increased with a correction duty proportional to the difference between the average current value and the allowable current value of the motor M detected, respectively, through the battery current detecting circuit 20 and the regenerative current detecting circuit 21. According to the constitution, the circuitry can be protected against breakdown due to overcurrent and the capacity of the motor M can be utilized to the maximum. |
