| 摘要 |
PURPOSE:To efficiently use a battery by preventing excessive quickening of time required until its output reaches the end voltage during discharge of the battery. CONSTITUTION:An inverter unit 4 controlled by a control circuit 8 drives an AC motor 5 by the output of a battery 1. An arithmetic circuit 10 estimates the residual capacity of the battery 1 based on a detecting signal Ic indicating a discharge current detected by a current sensor 9 and an output voltage Vc of the battery 1. A signal generating circuit 11 sets an allowable upper limit value Imax of the output current of the inverter unit 4 in such a manner that the Imax decreases at a predetermined rate as the level of signal Rc indicating a residual capacity calculated by the arithmetic circuit 10 becomes lower and said circuit 11 also gives an upper limit value command signal SImax indicating the allowable upper limit value Imax to the control circuit 8. The control circuit 8 controls in such a manner that the output current of the inverter unit 4 does not exceed said allowable limit value Imax of the inverter unit 4. |
