Power limiting circuit for electric vehicle battery charger
First Claim
1. An electric vehicle battery charging system where the batteries of an electric vehicle are charged from an external power source comprising:
- a battery energy management system (BEMS) monitoring the vehicle batteries and developing a current control command representing the charging current to be supplied to the vehicle batteries;
a controllable charger having a design power limit, said controllable charger being responsive to current control command from the BEMS, the current control command representing the charging current to be supplied by the controllable charger to the vehicle batteries; and
a charger power limiting circuit limiting power supplied by the controllable charger to below the charger design power limit including,a voltage sensor measuring the voltage of the vehicle batteries, andmeans for modifying the current control command to limit power to below at least an approximation of the design power limit of said charger based on the sensed battery voltage and the battery charging current, said means for modifying using the current control command from the BEMS to represent battery charging current without said controllable charger or charger power limiting circuit directly measuring charging current.
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Accused Products
Abstract
In an electric vehicle battery charging system where the batteries of an electric vehicle are charged from an external power source including a battery energy management system which monitors the vehicle batteries and develops a current control command representing the current to be supplied to the vehicle batteries and a controllable charger having a design power limit supplies current under command of the current command at a voltage of the vehicle batteries, a charger power limiting circuit is provided and includes a voltage sensor, and a circuit for modifying the current control command to limit power to be low at least in approximation of the designed power limit of the charger. The current control command modifying circuit modifies the current control command from the BEMS to ensure that the controllable charger will not supply power to the batteries in excess of the controllable chargers design power. The charger power limiting circuit includes a power limiting characteristic defining circuit, a current limiting feedback circuit and a power limiting characteristic defining circuit. The voltage of the vehicle batteries is sensed and the current control command from the battery energy management system is used as the charging current. The current control command is then modified to limit power to below at least an approximation of the design power limit of the charger.
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Citations
20 Claims
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1. An electric vehicle battery charging system where the batteries of an electric vehicle are charged from an external power source comprising:
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a battery energy management system (BEMS) monitoring the vehicle batteries and developing a current control command representing the charging current to be supplied to the vehicle batteries; a controllable charger having a design power limit, said controllable charger being responsive to current control command from the BEMS, the current control command representing the charging current to be supplied by the controllable charger to the vehicle batteries; and a charger power limiting circuit limiting power supplied by the controllable charger to below the charger design power limit including, a voltage sensor measuring the voltage of the vehicle batteries, and means for modifying the current control command to limit power to below at least an approximation of the design power limit of said charger based on the sensed battery voltage and the battery charging current, said means for modifying using the current control command from the BEMS to represent battery charging current without said controllable charger or charger power limiting circuit directly measuring charging current. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of charging electric vehicle batteries from an external power source using a controllable charger having a design power limit, comprising:
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a) monitoring the vehicle batteries and developing a current control command representing the charging current to be supplied to the vehicle batteries; b) using the controllable charger to charge said batteries with a current defined by said current control command; and c) limiting power supplied by the charger to below the charger design power by, i) sensing the voltage of the vehicle batteries, ii) using the current control command from the BEMS to represent battery charging current without said controllable charger directly measuring charging current, and iii) modifying the current control command to limit power to below at least an approximation of the design power limit of said charger. - View Dependent Claims (9, 10)
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11. In an electric vehicle battery charging system where the batteries of an electric vehicle are charged from an external power source by a controllable charger having a design power limit, said controllable charger being responsive to current control command from a battery energy management system (BEMS), the current control command representing the charging current to be supplied by the controllable charger to the vehicle batteries, a charger power limiter for limiting power supplied by the charger to below the charger design power comprising:
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a voltage sensor measuring the voltage of the vehicle batteries; and means for modifying the current control command to limit power to below at least an approximation of the design power limit of said charger based on the sensed battery voltage and the battery charging current, said means for modifying using the current control command from the BEMS to represent battery charging current without the controllable charger or said charger power limiter directly measuring charging current. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. In an electric vehicle battery charging system where the batteries of an electric vehicle are charged from an external power source by a controllable charger having a design power limit, said controllable charger being responsive to current control command from a battery energy management system (BEMS), the current control command representing the charging current to be supplied by the controllable charger to the vehicle batteries, a charger power limiting method for limiting power supplied by the charger to below the charger design power comprising:
- a) sensing the voltage of the vehicle batteries;
b) using the current control command from the BEMS to represent battery charging current without said charger directly measuring charging current; and
c) modifying the current control command to limit power to below at least an approximation of the design power limit of said charger based on the sensed battery voltage and the battery charging current. - View Dependent Claims (19, 20)
- a) sensing the voltage of the vehicle batteries;
Specification