| 摘要 |
A combined battery state of charge evaluator and motor control system for an electric vehicle comprises a traction battery 10, a motor controller 14, a traction motor 11, a micro computer 16 and an interface circuit 15. The micro computer 16 receives signals representing battery temperature, total battery voltage, and battery current and calculates the charge withdrawn from the battery by integrating battery current and also calculates the remaining charge in the battery as a function of battery voltage. By summing the remaining charge and the charge withdrawn, the present charge storage capacity value of the battery is calculated. The micro computer 16 compares the present charge storage capacity value with a value representing 85% of the nominal charge storage capacity of the battery when new and selects the lower of these two values. The state of charge is then calculated as a function of the charge withdrawn and this lower value and displayed on a meter 34. When the remaining charge in the battery calculated by subtracting the charge withdrawn from this lower value falls below 6% of the battery capacity, the current supply to the motor 11 is limited to a predetermined percentage of the current demanded by the driver. This predetermined percentage is progressively reduced as the remaining charge falls towards zero. <IMAGE> |
