Protection method for limited charging/discharging current of hybrid electric vehicle battery and a device and a system thereof

• US 8,423,211 B2
• Filed: 12/24/2008
• Issued: 04/16/2013
• Est. Priority Date: 12/29/2007
• Status: Active Grant

• Current Assignee: Chery Automobile Co., Ltd.
• Original Assignee: Chery Automobile Co., Ltd.
• Inventors: Li, Fang
• Primary Examiner(s): Tran, Khoi
• Assistant Examiner(s): LIN, ABBY YEE
• Application Number:
  US12/743,549
• Publication Number:
  US 20100250041A1
• Time in Patent Office: 1,574 Days
• Field of Search: 180 651- 658, 318/139, 320100-167, 701/22, 903902-960
• 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, by a processor;

determining, by the processor, a charging or discharging state of the battery, and calculating, by the processor, a limit torque value from a measured current 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 to a motor control unit, by the processor,

wherein calculating the limit torque value comprises when the battery is in a discharging state,

multiplying by a Hybrid Control Unit a 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 measured 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.

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

when the measured current value is above the initial control value of discharging current, performing Proportional integral feedback, 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 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.

3. 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.

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

a processor adapted to

receive a power request and to determine an initial torque value in response to the power request,

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, the BMS feedback values at least comprising a measured current value of the battery,

calculate a limit torque value from the limit power value and an angular velocity of a motor, and

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 to a motor control unit,

wherein calculating the limit torque value from the limit power value and an angular velocity of the motor comprises

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

a calculation unit adapted to calculate a limit torque value from the output limit power P.sub.2 and an angular velocity of the motor when the measured current value is below the initial control value of discharging current; and

to perform Proportional integral feedback PI adusting 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 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 measured current value is above the initial control value of discharging current.

5. 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 processor adapted to

receive a power request and to determine an initial torque value in response to the power request,

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, the BMS feedback values at least comprising a measured current value of the battery,

calculate a limit torque value from the limit power value and an angular velocity of a motor, and

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 to the motor control unit,

wherein calculating the limit torque value from the limit power value and an angular velocity of the motor comprises

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

a calculation unit adapted to calculate a limit torque value from the output limit power P.sub.2 and an angular velocity of the motor when the measured current value is below the initial control value of discharging current; and

to perform Proportional integral feedback, 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 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 measured current value is above the initial control value of discharging current.