| 摘要 |
<p>When a battery temperature is judged to be lower than a threshold value, an inverter control circuit alternately switches an AC motor operation point between an optimal operation point and a motor loss increase point. At the motor loss increase point, increase of the amplitude of the motor current increases the copper loss in the 3-phase coil of the AC motor. On the other hand, at the optimal operation point, decrease of the amplitude of the motor current reduces the copper loss. In accordance with the periodical increase/decrease of the copper loss, the battery is periodically charged and discharged by power corresponding to the copper loss. Fluctuation of battery current caused by this charge/discharge causes the internal resistor of the battery to evolve heat and increase the battery temperature. The temperature increase operation is inhibited when the motor temperature exceeds an allowable temperature which guarantees the operation efficiency of the AC motor.</p> |
