METHOD AND SYSTEM FOR BRAKING ELECTRIC VEHICLE

摘要

PURPOSE:To enhance safety of an electric vehicle by controlling the power factor of a motor depending on the storage condition of a battery thereby ensuring a required regenerative brake power without causing any damage on the battery. CONSTITUTION:In case of regenerative braking, the charged state of a battery is detected by a charges state detecting means 5. A charge control means 7 in a controller 3 receiving a detection signal delivers a charging command to a torque component current generating means 70 and an excitation component current generating means 71. The motor current is a sum of a torque component current It and an exciting component current I and the magnitudes thereof are controlled by a charge command delivered from a charge control means 7 thus varying the power factor. Losses of motor and inverter are decreased/ increased and the charging current is increased/decreased by controlling the power factor of the motor thus ensuring a constant brake power. Since a required regenerative brake power can be ensured without causing any damage on the battery, safety is enhanced in the operation of an electric vehicle.