Intelligent battery voltage regulation for hybrid vehicles
First Claim
1. A method for regulating a charge state of a traction battery in a hybrid vehicle having an internal combustion engine that is assisted for acceleration by an electric traction motor energized by the traction battery, said method comprising:
- detecting operation of said traction motor in one of an acceleration assist and regenerative braking modes;
only when said electric motor is not operated in one of said acceleration assist and regenerative braking modes, applying torque from said engine to operate said traction motor in a generator mode to supply a charging current to said battery; and
controlling operation of said traction motor in said generator mode such that said charging current charges the traction battery to a selected voltage regulation setpoint.
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Abstract
In a hybrid vehicle having an internal combustion engine that is assisted by an electric motor powered by a traction battery, the electric motor is operated in a generating mode to charge the vehicle battery during periods when neither acceleration assist nor regenerative braking are being performed. Torque of the electric motor is adjusted by a controller to generate a battery charge current which regulates the voltage of the battery to a selected setpoint. The setpoint is determined as a function of vehicle operating parameters, including but not limited to battery temperature.
18 Citations
15 Claims
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1. A method for regulating a charge state of a traction battery in a hybrid vehicle having an internal combustion engine that is assisted for acceleration by an electric traction motor energized by the traction battery, said method comprising:
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detecting operation of said traction motor in one of an acceleration assist and regenerative braking modes;
only when said electric motor is not operated in one of said acceleration assist and regenerative braking modes, applying torque from said engine to operate said traction motor in a generator mode to supply a charging current to said battery; and
controlling operation of said traction motor in said generator mode such that said charging current charges the traction battery to a selected voltage regulation setpoint. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
detecting a voltage output from said traction battery;
calculating an error signal by subtracting said voltage output from said voltage regulation setpoint;
utilizing said error signal for generating a torque demand signal; and
controlling operation of the traction motor according to the torque demand signal.
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3. The method according to claim 2, wherein said step of controlling operation of said traction motor comprises controlling torque of said motor.
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4. The method according to claim 3, wherein controlling torque of said traction motor is performed by adjusting motor phase current of said traction motor.
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5. The method according to claim 1, wherein said voltage regulation setpoint is determined based on operating parameters of said vehicle.
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6. The method according to claim 5, wherein said operating parameters include at least a temperature of said battery.
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7. The method according to claim 1, wherein said step of controlling operation of said traction motor comprises:
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a control unit generating a torque command as a function of vehicle operating parameters, including traction battery voltage; and
controlling said traction motor to generate a torque corresponding to the torque command.
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8. The method according to claim 7, wherein controlling operation of said traction motor is performed by adjusting a motor phase current of said traction motor.
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9. An apparatus for regulating a charge state of a traction battery in a hybrid vehicle having an internal combustion engine that is assisted for acceleration and deceleration by an electric traction motor that is energized by the traction battery, said apparatus comprising:
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detector means for detecting operation of said traction motor in one of an acceleration assist and regenerative braking modes;
a computer receiving signals from said detector means, and having a memory encoded with a program for only when said traction motor is not operated in one of said acceleration assist and regenerative braking modes, causing said traction motor to operate in a generator mode by absorbing torque from said engine, thereby generating a charging current to said battery; and
controlling operation of said traction motor in said generator mode such that said charging current charges the traction battery to a selected voltage regulation setpoint. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification