PROTECTION METHOD FOR LIMITED CHARGING/DISCHARGING CURRENT OF HYBRID ELECTRIC VEHICLE BATTERY AND A DEVICE AND A SYSTEM THEREOF

• US 20100250041A1
• Filed: 12/24/2008
• Published: 09/30/2010
• Est. Priority Date: 12/29/2007
• Status: Active Grant

• Current Assignee: Chery Automobile Co., Ltd.
• Original Assignee: Chery Automobile Co., Ltd.
• Inventors: Li, Fang
• Granted Patent: US 8,423,211 B2
• Time in Patent Office: Days
• US Class Current: 701/22
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 2510/24 Energy storage means
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

A limited protection method for charging/discharging current of hybrid electric vehicle battery and a device and a system thereof is disclosed. Said method includes: receiving a power requirement and determining an original torque based on the power requirement; judging a charge/discharge state of the battery and acquiring a limited torque from an actual current and a predefined torque; comparing said original torque with the limited torque to select the smaller one as a final output requirement. The embody of the invention can achieve the real-time limited protection for charge/discharge current of hybrid electric vehicle battery.

Claims

1. A method for protective limiting of charging and discharging current of a battery in a hybrid powered vehicle, comprising:

receiving a power request and determining an initial torque value in response to the power request;

determining a charging or discharging state of the battery and calculating a limit torque value from an actual current value and a predetermined limit value; and

comparing the initial torque value and the limit torque value and selecting the smaller one of them as a torque request value to be finally output.

2. The method according to claim 1, wherein when the battery is in a charging state, calculating the limit torque value comprises:

when the battery is in a charging state, multiplying by a Hybrid Control Unit an actually measured voltage value of the battery by a charging current limit value of the battery to derive a charging limit power P₁; and

when the actual current value is below an initial control value of charging current, taking a output limit power P<sub>limit—

1</sub> as P₁, and calculating a limit torque value from the output limit power and an angular velocity of the motor.

3. The method according to claim 2, wherein calculating the limit torque value further comprises:

when the actual current value is above the initial control value of charging current, performing PI adjusting with I_error=I_battery−

I<sub>charge—

limit</sub> to derive a torque deviation value P<sub>PI—

1</sub>, wherein I_battery is the actually measured current value of the battery, and I<sub>charge—

limit</sub> is the charging current limit value of the battery;

deriving a resultant output limit power P<sub>limit—

1</sub>=P₁+P<sub>PI—

1</sub> from P<sub>PI—

1</sub> and P₁; and

calculating a limit torque value from the output limit power P<sub>limit—

1</sub> and an angular velocity of the motor.

4. The method according to claim 1, wherein calculating the limit torque value comprises:

when the battery is in a discharging state, multiplying by a Hybrid Control Unit an actually measured voltage value of the battery by a discharging current limit value of the battery to derive a discharging limit power P₂; and

when the actual current value is below an initial control value of discharging current, taking a output limit power P<sub>limit—

2</sub> as P₂, and calculating a limit torque value from the output limit power and an angular velocity of the motor.

5. The method according to claim 4, wherein calculating the limit torque value further comprises:

when the actual current value is above the initial control value of discharging current, performing PI adjusting with I_error=I_battery−

I<sub>discharge—

limit</sub> to derive a torque deviation value P<sub>PI—

2</sub>, wherein I_battery is the actually measured current value of the battery, and I<sub>discharge—

limit</sub> is the discharging current limit value of the battery;

deriving a resultant output limit power P<sub>limit—

2</sub>=P₂+P<sub>PI—

2</sub> from P<sub>PI—

2</sub> and P₂; and

calculating a limit torque value from the output limit power P<sub>limit—

2</sub> and an angular velocity of the motor.

6. The method according to claim 1, wherein determining a charging or discharging state of the battery comprises:

determining a charging or discharging state of the battery from voltage and current signals of the high voltage battery.

7. A device for protective limiting of charging and discharging current of a battery in a hybrid powered vehicle, comprising:

a first processing unit adapted to receive a power request and to determine an initial torque value in response to the power request;

a second processing unit adapted to determine a charging or discharging state of the battery and to calculate a limit power value of charging or discharging the battery from BMS feedback values;

a third processing unit adapted to calculate a limit torque value from the limit power value and an angular velocity of a motor; and

a fourth processing unit adapted to compare the initial torque value and the limit torque value and to select the smaller one of them as a torque request value to be finally output.

8. The device according to claim 7, wherein the third processing unit comprises:

a first comparison unit 51 adapted to compare an actual current value and an initial control value of charging current; and

a first calculation unit 52 adapted to calculate a limit torque value from the output limit power P₁ and an angular velocity of the motor when the actual current value is below the initial control value of charging current, and to perform PI adjusting with I_error=I_battery−

I_charge—

limit to derive a torque deviation value P<sub>PI—

1</sub>, where I_battery is the actually measured current value, and I<sub>charge—

limit</sub> is the charging current limit value of the battery, to derive a resultant output limit power P<sub>limit—

1</sub>=P₁+P<sub>PI—

1</sub> from P<sub>PI—

1</sub> and P₁, and to calculate a limit torque value from the output limit power P<sub>limit—

1</sub> and an angular velocity of the motor when the actual current value is above the initial control value of charging current.

9. The device according to claim 7, wherein the third processing unit comprises:

a second comparison unit adapted to compare an actual current value and an initial control value of discharging current; and

a second calculation unit adapted to calculate a limit torque value from the output limit power P₂ and an angular velocity of the motor when the actual current value is below the initial control value of discharging current; and

to perform PI adjusting with I_error=I_battery−

I<sub>discharge—

limit</sub> to derive a torque deviation value P<sub>PI—

2</sub>, wherein I_battery is the actually measured current value of the battery, and I<sub>discharge—

limit</sub> is the discharging current limit value of the battery, to derive a resultant output limit power P<sub>limit—

2</sub>=P₂+P<sub>PI—

2</sub> from P<sub>PI—

2</sub> and P₂, and to calculate a limit torque value from the output limit power P<sub>limit—

2</sub> and an angular velocity of the motor when the actual current value is above the initial control value of discharging current.

10. A hybrid powered vehicle system, comprising a Battery Management System BMS, a Hybrid Control Unit HCU, an Engine Management System EMS, a Motor Control Unit MCU, a motor, an engine, a synthesizer and a power transmission system, wherein the HCU comprises a device for protective limiting of charging and discharging current of a battery and the device comprises:

a first processing unit adapted to receive a power request and to determine an initial torque value in response to the power request;

a second processing unit adapted to determine a charging or discharging state of the battery and to calculate a limit power value of charging or discharging the battery from BMS feedback values;

a third processing unit adapted to calculate a limit torque value from the limit power value and an angular velocity of a motor; and

a fourth processing unit adapted to compare the initial torque value and the limit torque value and to select the smaller one of them as a torque request value to be finally output.