Brake system for electric automobile

PURPOSE:To enhance response of regenerative brake torque by generating regenerative brake torque with a rising time constant approximate to that of mechanical brake torque. CONSTITUTION:Exciting current of a drive motor 10 begins to rise after production of a brake signal through turn ON of a brake switch 34 and before generation of mechanical brake torque. Torque current determining the rising of regenerative brake torque is increased synchronously with generation of mechanical brake torque. Since the exciting current has already been increased somewhat at a point of time when the torque current increases, regenerative brake torque to be determined by a product of the exciting current and the torque current rises relatively quickly. Consequently, when it is required to start the exciting current component under field weakening control, regenerative brake torque can be started as quickly as mechanical brake torque.