System and method for estimating allowable regenerative braking of vehicle

1. A system for estimating allowable regenerative braking of a vehicle, comprising:

a motor control unit (MCU) to provide a charging power limit of a motor as a first input;

a battery management system (BMS) to provide a charging power limit of a battery as a second input;

an active hydraulic brake (AHB) to input allowable regenerative braking as a third input; and

a hydraulic control unit (HCU) to estimate final allowable regenerative braking using the first, second, and third inputs,

wherein the HCU comprises:

a first operator to output an estimated charging power limit of the motor by dividing the charging power limit of the battery received from the BMS by a motor-inverter-battery efficiency,

a first comparator to compare the charging power limit of the motor received from the MCU with an output from the first operator and to output a minimum value of the charging power limit of the motor received from the MCU and the output from the first operator;

a second operator to output an estimated charging torque limit of the motor based on the output from the first comparator;

a second comparator to compare the estimated charging torque limit of the motor and the allowable regenerative braking received from the AHB to output a minimum value of the estimated charging torque limit of the motor and the allowable regenerative braking; and

a third operator to estimate the final allowable regenerative braking based on an output from the second comparator.

2. The system of claim 1 , wherein the second operator estimates the charging torque limit of the motor by dividing the charging power limit of the motor received from the first comparator by a wheel speed.

3. A method of estimating allowable regenerative braking for a vehicle, comprising:

(a) estimating, by a hydraulic control unit (HCU), a charging power limit of a motor based on a charging power limit of a battery from a battery management system (BMS);

(b) comparing, by the HCU, the charging power limit of the motor estimated in step (a) with a charging power limit of the motor received from a motor control unit (MCU);

(c) estimating, by the HCU, a charging torque limit of the motor based on a smaller one of the compared results in step (b);

(d) comparing, by the HCU, the charging torque limit of the motor estimated in step (c) with an allowable regenerative braking received from an active hydraulic brake (AHB);

(e) estimating, by the HCU, a final allowable regenerative braking based on a smaller one of the compared results in step (d)

(f) transmitting by the HCU the estimated final allowable regenerative braking value to an active hydraulic brake (AHB); and

(g) operating, by the AHB, a hydraulic brake based on the estimated final allowable regenerative braking value.

4. The method of claim 3 , wherein in step (a) the charging power limit of the motor is estimated by dividing the charging power limit of the battery by a motor-inverter-battery efficiency.

5. The method of claim 3 , wherein in step (c) the charging torque limit of the motor is estimated by dividing the charging power limit of the motor by a wheel speed.

6. A system for estimating allowable regenerative braking for a vehicle, comprising:

a motor control unit (MCU) to provide a charging power limit of a motor as a first input;

an active hydraulic brake (AHB) to provide an allowable regenerative braking as a second input; and

a hydraulic control unit (HCU) to estimate a final allowable regenerative braking using the charging power limit of the motor and the allowable regenerative braking as the first and second inputs,

wherein the HCU comprises:

a first operator to output an estimated charging torque limit of the motor based on the charging power limit of the motor receiving from the MCU;

a comparator to compare the estimated charging torque limit of the motor with the allowable regenerative braking received from the AHB and to output a minimum value of the estimated charging torque limit of the motor and the allowable regenerative braking; and

a second operator to estimate the final allowable regenerative braking based on an output from the comparator.

7. A system for estimating allowable regenerative braking for a vehicle, comprising:

a battery management system (BMS) to provide a charging power limit of a battery as a first input;

an active hydraulic brake (AHB) to provide an allowable regenerative braking as a second input; and

a hydraulic control unit (HCU) to estimate a final allowable regenerative braking using the first and second inputs,

wherein the HCU includes a first operator to output an estimated charging power limit of the motor by dividing the charging power limit of the battery received from the BMS by a motor-inverter-battery efficiency, and

wherein the HCU comprises:

a second operator to estimate a charging torque limit of the motor based on an input from the first operator;

a comparator to compare the charging torque limit of the motor received from the second operator with the allowable regenerative braking received from the AHB and to output a minimum value of the charging torque limit of the motor and the allowable regenerative braking; and

a third operator to estimate the final allowable regenerative braking based on an output from the comparator.

8. The system of claim 7 , wherein the second operator estimates the charging torque limit of the motor by dividing a charging power limit of the motor received from the first operator by a wheel speed.