Intelligent battery charger for electric drive system batteries

A method for charging a rechargeable battery pack, comprising the steps of;

• sensing discharge current of the battery pack as a function of time;
• computing, from the sensed discharge current and time duration of discharge, net ampere-hours discharged by the battery;
• and
• recharging the battery until at least the computed net ampere-hours of discharge is returned to the battery.

A battery charger for a battery coupled for supplying power to an electric drive system of an electric motor propelled vehicle, the vehicle being selectively operative in an electrical braking mode wherein the motor operates as an electrical generator for returning power to the battery, the charger comprising:

• regulating means for receiving substantially constant voltage power and conditioning the power for application to a battery to be charged;
• control means coupled to said regulating means and adapted to control said regulating means to introduce a controlled amount of electrical charge to the battery;
• and
• monitoring means coupled to the battery for measuring total discharge current, as a function of time, from the battery while the motor is operative in a propulsion mode and for measuring total charge current, as a function of time, while the motor is operative in a braking mode, said monitoring means including means for converting said measured charge and discharge currents to a net ampere-hours of discharge;
• said control means being coupled to said monitoring means for establishing operation of the battery charger to recharge the battery with an amount of electrical charge corresponding to at least said net ampere-hours of discharge.

A battery charger for a battery coupled for supplying power to an electric drive system of an electric motor propelled hybrid vehicle, the vehicle having an internal combustion engine coupled to electric generating means for providing the vehicle with propulsion power at selected times and for controllably charging the battery, the vehicle being selectively operative in an electrical braking mode wherein the motor operates as an electrical generator for returning power to the battery, the charger comprising:

• regulating means for receiving substantially constant voltage power and conditioning the power for application to a battery to be charged;
• control means coupled to said regulating means and adapted to control said regulating means to introduce a controlled amount of electrical charge to the battery;
• and
• monitoring means coupled to the battery for measuring total discharge current, as a function of time, from the battery while the motor is operative in a propulsion mode, for measuring total charge current, as a function of time, while the motor is operative in a braking mode, and for measuring electrical power returned to the battery during operation of said engine, said monitoring means including means for converting said measured charge and discharge currents to a net ampere-hours of discharge and for adjusting said net ampere-hours of discharge by an amount corresponding to said measured electrical power;
• said control means being coupled to said monitoring means for establishing operation of the battery charger to recharge the battery with an amount of electrical charge corresponding to at least said net ampere-hours of discharge.