Power battery output power control method in speed control mode of pure electric heavy truck

Abstract

The application discloses a kind of power battery output power control methods under the speed control mode of pure electric heavy truck, comprising:1) calculate A Dchg And A Chg ;2) calculate B Dchg And B Chg ;3) according to the calculation result of step 1), 2) determine C Dchg And C Chg ;According to the result of step 3) and motor rated speed upper and lower limit value respectively determine D UnfilMax And D UnfilMin ;4) calculate E Dchg And E Chg ;5) according to the result of step 4) respectively G Max And G Min ;According to G Max And G min The motor demand speed instruction issued by driver is limited.The beneficial technical effect of the application is: after using the scheme, the final executed speed of power motor can be kept in the allowed range at all times, prevent the actual power of power battery from exceeding the allowed charging and discharging power range, and the battery is protected.

Description

Technical Field

[0001] This invention relates to a control technology for pure electric heavy-duty trucks, and more particularly to a method for controlling the output power of a power battery in a pure electric heavy-duty truck speed control mode. Background Technology

[0002] Power battery charging and discharging power control is a very important technology in the control of pure electric vehicles, and it is of great significance for battery protection. In operating conditions such as power take-off control and gearbox shifting, the power motor speed control mode is used. In these modes, if the power motor operates directly at the speed required by the driver, the actual power of the power battery may exceed the allowable charging and discharging power range. Over time, this will damage the power battery and shorten its life. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to limit the speed required by the driver by limiting the allowable charging and discharging power range, thereby protecting the power battery and extending its service life.

[0004] The specific technical solution is as follows:

[0005] An innovative method for controlling the output power of a power battery in a pure electric heavy-duty truck speed control mode is as follows: The method includes:

[0006] 1) Calculate the usable mechanical power of the motor based on the battery's allowable charge / discharge power and the motor efficiency; calculate A based on the motor's usable mechanical power and the motor's actual torque. Dchg and A Chg ;

[0007] The A Dchg The forward motor speed limit is obtained based on the battery's allowable discharge power; the A Chg The negative motor speed limit is obtained based on the battery's allowable charging power;

[0008] 2) Calculate B based on the battery's allowable charge / discharge power and the motor's external characteristics. Dchg and B Chg ;

[0009] The B Dchg The B is the forward motor speed limit obtained based on the motor's external characteristics; Chg The negative motor speed limit is obtained based on the motor's external characteristics;

[0010] 3) Take A Dchg and B Dchg The minimum of the two is taken as the forward speed limit C. Dchg Take A Chg and B ChgThe maximum of the two is used as the negative speed limit C. Chg ;

[0011] Choose C Dchg C Chg The maximum value among the three values ​​(including the rated speed limit of the motor) is used as the upper limit value of the motor power limiting speed D. UnfilMax Take C Dchg C Chg The minimum value among the three values ​​(including the motor's rated speed lower limit, and the speed limit D) is used as the lower limit value of the motor's power limiting speed. UnfilMin ;

[0012] 4) The integral value E is obtained by integrating the difference between the battery's allowable charging and discharging power and the motor's actual power consumption. Dchg and E Chg ;

[0013] The E Dchg E is the integral value of the difference between the allowable discharge power of the battery and the actual power consumed by the motor under the discharge state of the power battery; Chg The integral value of the difference between the allowable charging power of the battery and the actual power consumed by the motor when the power battery is charging.

[0014] 5) According to E Dchg For D UnfilMax By limiting the gradient of change, the upper speed control value G is obtained. Max According to E Chg For D UnfilMin By limiting the gradient of the speed change, the lower limit control value G of the rotational speed is obtained. Min ;

[0015] Finally, according to G Max and G min Limit the motor speed commands issued by the driver.

[0016] The beneficial technical effect of this invention is that it proposes a method for controlling the output power of the power battery in the pure electric heavy truck speed control mode. After adopting this scheme, the final speed of the power motor can always be kept within the allowable range, preventing the actual power of the power battery from exceeding the allowable charging and discharging power range, thus protecting the battery. Implementation

[0017] An innovative method for controlling the output power of a power battery in a pure electric heavy-duty truck speed control mode is as follows: The method includes:

[0018] 1) Calculate the usable mechanical power of the motor based on the battery's allowable charge / discharge power and the motor efficiency; calculate A based on the motor's usable mechanical power and the motor's actual torque. Dchg and A Chg ;

[0019] The A Dchg The forward motor speed limit is obtained based on the battery's allowable discharge power; the A Chg The negative motor speed limit is obtained based on the battery's allowable charging power;

[0020] 2) Calculate B based on the battery's allowable charge / discharge power and the motor's external characteristics. Dchg and B Chg ;

[0021] The B Dchg The B is the forward motor speed limit obtained based on the motor's external characteristics; Chg The negative motor speed limit is obtained based on the motor's external characteristics;

[0022] 3) Take A Dchg and B Dchg The minimum of the two is taken as the forward speed limit C. Dchg Take A Chg and B Chg The maximum of the two is used as the negative speed limit C. Chg ;

[0023] Choose C Dchg C Chg The maximum value among the three values ​​(including the rated speed limit of the motor) is used as the upper limit value of the motor power limiting speed D. UnfilMax Take C Dchg C Chg The minimum value among the three values ​​(including the motor's rated speed lower limit, and the speed limit D) is used as the lower limit value of the motor's power limiting speed. UnfilMin ;

[0024] 4) The integral value E is obtained by integrating the difference between the battery's allowable charging and discharging power and the motor's actual power consumption. Dchg and E Chg ;

[0025] The E Dchg E is the integral value of the difference between the allowable discharge power of the battery and the actual power consumed by the motor under the discharge state of the power battery; Chg The integral value of the difference between the allowable charging power of the battery and the actual power consumed by the motor when the power battery is charging.

[0026] 5) According to E Dchg For D UnfilMax By limiting the gradient of change, the upper speed control value G is obtained. Max According to E Chg For D UnfilMin By limiting the gradient of the speed change, the lower limit control value G of the rotational speed is obtained. Min ;

[0027] Finally, according to GMax and G min Limit the motor speed commands issued by the driver.

Claims

1. A method for controlling the output power of a power battery in a speed control mode of a pure electric heavy truck, characterized in that: The method comprises: 1) According to the battery allowed charging and discharging power and the motor efficiency, the motor available mechanical power is calculated; according to the motor available mechanical power and the motor actual torque, A Dchg and A Chg are calculated; The A Dchg is a positive motor speed limit value based on the battery allowed discharging power; the A Chg is a negative motor speed limit value based on the battery allowed charging power; 2) Calculate B according to the allowed charge-discharge power of the battery and the motor external characteristic Dchg and B Chg ; The B Dchg is a positive motor speed limit value obtained based on the motor external characteristic; and Chg is a negative motor speed limit value obtained based on the motor external characteristic. 3) take the minimum of A and B Dchg and C Dchg as the positive rotational speed limit C Dchg ; take the maximum of A and B Chg and C Chg as the negative rotational speed limit C Chg ; Choose C Dchg C Chg The maximum value among the three values ​​(including the rated speed limit of the motor) is used as the upper limit value of the motor power limiting speed D. UnfilMax Take C Dchg C Chg The minimum value among the three values ​​(including the motor's rated speed lower limit, and the speed limit D) is used as the lower limit value of the motor's power limiting speed. UnfilMin ; 4) Integral value E is calculated by integrating the difference between the allowed charging and discharging power of the battery and the actual consumed power of the motor Dchg and E Chg ; The E Dchg is the integral value of the difference between the allowable discharging power of the power battery and the actual consumed power of the motor in the discharging state of the power battery; the E Chg is the integral value of the difference between the allowable charging power of the power battery and the actual consumed power of the motor in the charging state of the power battery. 5) According to E Dchg For D UnfilMax By limiting the gradient of change, the upper speed control value G is obtained. Max According to E Chg For D UnfilMin By limiting the gradient of the speed change, the lower limit control value G of the rotational speed is obtained. Min ; Finally, according to G Max and G min The motor demand speed command issued to the driver is limited.