Control method for propulsion battery regeneration in an electric vehicle
First Claim
1. A regeneration control method for an electric vehicle having a plurality of drive wheels, an electric drive motor coupled to the drive wheels, propulsion batteries coupled to the drive motor, and a controller that generates a regeneration torque command for the motor, the control method comprising the steps of:
- measuring the speeds of said drive wheels;
comparing the absolute value of a difference between the measured speeds to a predetermined difference threshold,if the absolute value of said difference is less than the predetermined difference threshold, generating a regeneration torque command that is equal to a current value of the regeneration torque command, andif the absolute value of said difference is greater than or equal to the predetermined difference threshold, generating a regeneration torque command that is equal to the current value of the regeneration torque command times a reduction scale factor, to reduce the amount of battery regeneration to a level that does not lock up the drive wheels.
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Abstract
A system and methods that provide for battery regeneration in electric vehicles without employing brake blending. Wheel speed sensors provide speed inputs to a controller, for example, that are processed to control the torque commands issued to a motor of the vehicle, which allows a higher level of battery regeneration without causing drive wheels to lock up. In the present invention, speed inputs derived from the wheel speed sensors are sampled. The absolute value of the difference between the input signals derived from the wheel speed sensors is compared to a predetermined difference threshold. If the absolute value of the difference between the input signals is less than the predetermined difference threshold, a regeneration torque command is generated to control the torque output of the motor that is equal to a current value of the regeneration torque command. If the absolute value of the difference between the input signals is greater than or equal to the predetermined difference threshold, a regeneration torque command is generated that is equal to the current value of the regeneration torque command times a reduction scale factor, to reduce the amount of battery regeneration to a level that does not lock up the wheels.
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Citations
8 Claims
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1. A regeneration control method for an electric vehicle having a plurality of drive wheels, an electric drive motor coupled to the drive wheels, propulsion batteries coupled to the drive motor, and a controller that generates a regeneration torque command for the motor, the control method comprising the steps of:
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measuring the speeds of said drive wheels; comparing the absolute value of a difference between the measured speeds to a predetermined difference threshold, if the absolute value of said difference is less than the predetermined difference threshold, generating a regeneration torque command that is equal to a current value of the regeneration torque command, and if the absolute value of said difference is greater than or equal to the predetermined difference threshold, generating a regeneration torque command that is equal to the current value of the regeneration torque command times a reduction scale factor, to reduce the amount of battery regeneration to a level that does not lock up the drive wheels. - View Dependent Claims (2, 3, 4, 5)
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6. A regeneration control method for an electric vehicle having a plurality of drive wheels, an electric drive motor coupled to the drive wheels, propulsion batteries coupled to the drive motor, and a controller that generates a regeneration torque command for the motor, and a plurality of wheel speed sensors coupled to the drive wheels, said control method comprising the steps of:
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sampling speed inputs derived from respective pairs of a plurality of pairs of wheel speed sensors; comparing the absolute value of the difference between a first pair of input signals derived from a first pair of wheel speed sensors to a first predetermined difference value, and if this first absolute value is less than a first predetermined difference value, then comparing the absolute value of the difference between the input signals derived from a second pair of wheel speed sensors to a second predetermined difference value, and if this second absolute value is less than the second predetermined difference value, then comparing the absolute value of the difference between the input signals derived from a third pair of wheel speed sensors to a third predetermined difference value, and if this third absolute value is less than the third predetermined difference value, then generating a regeneration torque command that is equal to the current value of the regeneration torque command, and if the absolute value of the difference between any of the pairs of input signals is greater than or equal to any of the respective predetermined difference values, then generating a regeneration torque command that is equal to the current value of the regeneration torque command times a reduction scale factor. - View Dependent Claims (7, 8)
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Specification