Closed loop control of battery power limits based on voltage
First Claim
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1. A method for controlling battery discharge power limits for an electric battery in a vehicle powertrain, the battery being a source of power for an electric motor, the battery having a calibrated voltage set point that defines a limit for battery discharge voltage, the method comprising:
- measuring actual battery current;
measuring an error between the battery discharge voltage set point and the actual battery voltage using the actual voltage in a voltage closed loop feedback control;
determining a battery discharge power limit;
computing a voltage proportional term and a voltage integral term based on the error; and
multiplying the sum of the proportional term and the integral term by the actual battery current to obtain a power limit modification thereby preventing a battery discharge voltage in excess of the battery discharge set point.
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Abstract
A controller and a control method for modifying battery discharge and charge power limits in a vehicle powertrain that includes an electric battery as a power source. The modification compensates for inaccurate estimates of battery discharge and charge power limits by using a closed loop feedback control based on error between a battery voltage set point and commanded battery voltage.
35 Citations
17 Claims
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1. A method for controlling battery discharge power limits for an electric battery in a vehicle powertrain, the battery being a source of power for an electric motor, the battery having a calibrated voltage set point that defines a limit for battery discharge voltage, the method comprising:
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measuring actual battery current; measuring an error between the battery discharge voltage set point and the actual battery voltage using the actual voltage in a voltage closed loop feedback control; determining a battery discharge power limit; computing a voltage proportional term and a voltage integral term based on the error; and multiplying the sum of the proportional term and the integral term by the actual battery current to obtain a power limit modification thereby preventing a battery discharge voltage in excess of the battery discharge set point. - View Dependent Claims (3, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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2. A method for controlling battery charge power limits for an electric battery in a vehicle powertrain having an electric battery as a source of power for an electric motor, the battery being a source of power for an electric motor, the battery having a calibrated voltage set point that defines a limit for battery charge voltage, the method comprising:
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measuring an error between the battery charge voltage set point and actual battery voltage using actual voltage in a voltage closed loop feedback control; determining a battery charge power limit; computing a voltage proportional term and a voltage integral term based on the error; measuring actual battery current; and multiplying the sum of the proportional term and the integral term by the actual battery current to obtain a power limit modification thereby preventing a battery charge voltage in excess of the battery charge set point. - View Dependent Claims (4)
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5. A control system for a battery power limit in a vehicle powertrain in which a battery is a vehicle power source comprising:
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a battery controller; a motor driveably connected to a power output, the motor being electrically coupled to the battery controller; a vehicle system controller for receiving driver commands and delivering control commands to the motor; a proportional-integral controller with a battery voltage set point input, a battery voltage input and a battery current input; a comparator communicating with the vehicle system controller and the proportional-integral controller whereby battery power limits are compared to power limits established by the battery controller; the vehicle system controller being configured to develop battery power commands in response to driver commands; and a power limit closed loop control communicating with the proportional-integral controller and with the battery whereby a power limit for the battery is modified to maintain battery voltage at a value that does not exceed the battery voltage set point. - View Dependent Claims (6, 7)
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Specification