CN109910627B - Method for calculating braking recovery energy of planetary series-parallel hybrid electric vehicle - Google Patents

Abstract

The invention discloses a method for calculating braking recovery energy of a planetary series-parallel hybrid electric vehicleBrake pedal opening degree gamma and motor MG2 rotating speed n based on planetary series-parallel hybrid electric vehicle_MG2Judging the energy recovery mode of the current vehicle according to the vehicle speed v and the battery SOC value, and respectively calculating the initial braking energy recovery power values of the vehicle under the N gear and the D gear according to the vehicle mode; then, considering the influence of engine braking and motor MG2 temperature change on the vehicle braking recovery power when the vehicle is braked with gear, reasonable offset and temperature correction factor are set, and the actual values of the braking energy recovery power of the vehicle under N gear and D gear are obtained. The method solves the problems of large error and low precision in the existing calculation method, and can improve the accuracy and reliability of the calculation of the vehicle braking energy recovery power.

Description

Method for calculating braking recovery energy of planetary series-parallel hybrid electric vehicle

Technical Field

The invention belongs to the technical field of new energy automobiles, and particularly relates to a method for calculating braking recovery energy of a planetary series-parallel hybrid electric vehicle.

Background

At present, under the background that the pressure of energy and environment is increasing, the development of a low-carbon environment-friendly new energy automobile becomes a focus of social attention, wherein the planetary hybrid electric vehicle becomes one of the hot directions of the new energy automobile due to good fuel economy and less emission. In order to make up the deficiency of the endurance capacity of the power battery of the planetary series-parallel hybrid electric vehicle, the regenerative braking mode is adopted to recover the braking energy, which has great significance for improving the driving mileage of the vehicle. Therefore, how to realize accurate calculation of automobile braking recovery energy is an urgent problem to be solved for the planetary series-parallel hybrid electric vehicle.

In the prior art, patents of methods for calculating braking recovery energy of a planetary hybrid electric vehicle are not available, the influence of temperature change of a motor MG2 on braking recovery energy in the braking process of the vehicle is not considered in the traditional calculation method, and the difference between the obtained result and the true value is large. Therefore, it is necessary to provide a method for calculating the braking energy recovery of a planetary hybrid electric vehicle to accurately calculate the braking energy recovery power of the vehicle in different braking energy recovery modes.

Disclosure of Invention

The invention provides a method for calculating the braking energy recovery of a planetary series-parallel hybrid electric vehicle, which solves the problems of large error and low precision in the conventional method for calculating the braking energy recovery of the planetary series-parallel hybrid electric vehicle, and can improve the accuracy and reliability of the calculation of the braking energy recovery power of the vehicle.

In order to achieve the above object, a method for calculating braking recovery energy of a planetary hybrid electric vehicle according to an embodiment of the present invention includes the following steps:

step 1, acquiring the opening gamma of a brake pedal and the rotating speed n of a motor MG2 through a sensor_MG2State quantity information such as automobile speed v and battery SOC value;

step 2, according to the opening gamma of a brake pedal of the planetary series-parallel hybrid electric vehicle and the rotating speed n of the motor MG2_MG2Judging the energy recovery mode of the current vehicle according to the vehicle speed v and the battery SOC value;

step 2(a), if the triggering condition of the braking energy recovery mode in the formula (1) is met, the vehicle enters the braking energy recovery mode;

in the formula (1), gamma_{Brk_lo}Is the lower limit value, gamma, of the opening degree of a brake pedal in a brake energy recovery mode_{Brk_hi}Upper limit value, n, of opening of brake pedal in braking energy recovery mode_BrkIs the lowest rotation speed, v, of the motor MG2 in the braking energy recovery mode_BrkMinimum vehicle speed, soc, required for the braking energy recovery mode_{Brk_hi}The upper limit value of the battery SOC in the braking energy recovery mode;

step 2(b), if the condition for triggering the sliding energy recovery mode in the formula (2) is met, the vehicle enters the sliding energy recovery mode;

in the formula (2), gamma_{Slide_lo}Is the lower limit value of the opening degree of a brake pedal in a coasting energy recovery mode, gamma_{Slide_hi}Upper limit value, n, of opening of brake pedal in coasting energy recovery mode_SlideIs the lowest rotation speed, v, of the motor MG2 in the coasting energy recovery mode_SlideMinimum vehicle speed, soc, required for the coasting energy recovery mode_{Slide_hi}The upper limit value of the battery SOC in the coasting energy recovery mode;

step 2(c), if the two mode triggering conditions are not met, the vehicle enters a non-recovery mode;

step 3, respectively calculating the initial values of the braking energy recovery power of the vehicle under the N gear and the D gear according to the mode of the vehicle in the step 2;

step 3(a), the vehicle is in a braking energy recovery mode, and the initial value P of the braking energy recovery power of the vehicle under the N gear and the D gear_{Brk_reg_N_ini}The opening degree gamma of the brake pedal and the rotation speed n of the motor MG2 are calculated_MG2Obtaining the result by looking up a table;

step 3(b), the vehicle is in a sliding energy recovery mode, and the initial value P of the sliding energy recovery power of the vehicle in the N gear and the D gear_{Slide_reg_N_ini}The motor speed is obtained by looking up a table according to the rotating speed of the motor MG2 and the rotating speed change rate of the motor MG 2;

step 3(c), the vehicle is in a non-recovery mode, and the energy recovery power of the vehicle is 0 at the moment;

step 4, according to the mode of the vehicle in the step 2, considering the influence of the gear and the temperature change of the motor MG2 on the recovery power, respectively calculating the actual values of the braking energy recovery power of the vehicle under the N gear and the D gear;

step 4(a), the vehicle is in a braking energy recovery mode, and the initial value of the braking energy recovery power obtained in the step 3(a) is multiplied by a correction factor obtained by looking up the table of the motor MG2 temperature at the current moment to obtain the actual value of the required braking recovery power under the N gear; namely:

P_{Brk_reg_N}＝P_{Brk_reg_N_ini}×_T······················(3)

in the formula (3), P_{Brk_reg_N}The actual value of the braking recovery power in N gear when the vehicle is in the braking energy recovery mode, P_{Brk_reg_N_ini}The initial value of the braking recovery power under the N gear of the braking energy recovery mode is obtained;_Tis a temperature correction factor;

the method comprises the steps that when a vehicle is in a braking energy recovery mode, a correction amount is added to an initial braking recovery power value under the N gear, and then the sum is multiplied by a correction factor obtained by table look-up of the motor MG2 temperature at the current moment to obtain an actual value of the required braking recovery power under the D gear; namely:

P_{Brk_reg_D}＝(P_{Brk_reg_N_ini}+α_Brk)×_T···················(4)

in the formula (4), P_{Brk_reg_D}The actual value of the braking recovery power in the D gear, P, when the vehicle is in the braking energy recovery mode_{Brk_reg_N_ini}For the initial value of the braking recovery power in the braking energy recovery mode N gear, α_BrkIn order to consider the braking power correction amount of the engine brake when the vehicle is braked with gear under the braking energy recovery mode,_Tis a temperature correction factor;

step 4(b), when the vehicle is in the sliding energy recovery mode, the driver does not operate the brake pedal, and the opening gamma of the brake pedal is 0; multiplying the initial value of the sliding energy recovery power of the vehicle under the N gear by a correction factor obtained by table lookup of the temperature of the motor MG2 at the current moment to obtain an actual value of the required braking recovery power under the N gear; namely:

P_{Slide_reg_N}＝P_{Slide_reg_N_ini}×_T····················(5)

in the formula (5), P_{Slide_reg_N}The actual value of the recovered power in N gear, P, when the vehicle is in the sliding energy recovery mode_{Slide_reg_N_ini}The initial value of the braking recovery power under the sliding energy recovery mode N gear,_Tis a temperature correction factor;

when the vehicle is in a sliding energy recovery mode, adding correction quantity obtained by table lookup according to the rotating speed of MG2 and the rotating speed change rate of the motor MG2 to the initial value of the sliding energy recovery power of the N gear, and multiplying the correction quantity by the correction factor obtained by table lookup of the temperature of the motor MG2 at the current moment to obtain the actual value of the required braking recovery power under the D gear; namely:

P_{Slide_reg_D}＝(P_{Slide_reg_N_ini}+α_Slide)×_T·················(6)

in the formula (6), P_{Slide_reg_D}The actual value of the energy recovery power in the D gear, P, when the vehicle is in the sliding energy recovery mode_{Slide_reg_N_ini}Initial value of energy recovery power for coast energy recovery mode N range, α_SlideIn order to consider the braking power correction amount of the engine brake when the vehicle is braked with gear under the coasting energy recovery mode,_Tis a temperature correction factor.

Compared with the prior art, the invention has the beneficial effects that:

the method for calculating the braking recovery energy of the planetary hybrid electric vehicle is provided, the influence of engine braking and motor MG2 temperature change on the braking recovery power of the vehicle when the vehicle is braked in a gear is considered, the problems of large error and low precision in the conventional method for calculating the braking recovery energy of the planetary hybrid electric vehicle are solved, and the accuracy and the reliability of the calculation of the braking energy recovery power of the vehicle can be improved.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a flow chart of a method for calculating braking energy recovery of a planetary hybrid electric vehicle according to the present invention;

FIG. 2 is a flow chart of the present invention for determining the energy recovery mode of a planetary hybrid electric vehicle;

FIG. 3 is a flow chart of the calculation of the actual brake recovery power values of the planetary hybrid electric vehicle in different gears of the brake energy recovery mode according to the present invention;

FIG. 4 is a flow chart of actual values of braking recovery power of the planetary hybrid electric vehicle under different gears in the coasting energy recovery mode;

fig. 5 is a schematic configuration diagram of a planetary hybrid electric vehicle to which an embodiment of the present invention is applied.

Detailed Description

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar designations denote like or similar physical quantities or quantities with like or similar meanings. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it should be noted that, unless explicitly stated or limited otherwise, the terms "array" and "range" are to be interpreted broadly, and may be, for example, a set of equally spaced numbers or randomly spaced numbers, and the specific meaning of the terms may be understood by those skilled in the art according to specific situations.

Since the basic structure of a planetary hybrid electric vehicle is well known to those skilled in the art, it is not repeated herein, and only a schematic diagram of a typical configuration is shown in fig. 5.

A brake recovered energy calculation method for a planetary hybrid vehicle according to embodiments of the present invention will be described below with reference to the accompanying drawings, but the present invention is not limited to these embodiments.

The method shown in fig. 1 is a method for calculating the braking energy recovery of the planetary hybrid electric vehicle shown in fig. 5.

The method comprises the following steps:

step 1, acquiring the opening gamma of a brake pedal and the rotating speed n of a motor MG2 through a sensor_MG2State quantity information such as automobile speed v and battery SOC value;

step 2, according to the opening gamma of a brake pedal of the planetary series-parallel hybrid electric vehicle and the rotating speed n of the motor MG2_MG2Judging the energy recovery mode of the current vehicle according to the vehicle speed v and the battery SOC value;

step 2(a), if the triggering condition of the braking energy recovery mode in the formula (1) is met, the vehicle enters the braking energy recovery mode;

in the formula (1), gamma_{Brk_lo}Is the lower limit value, gamma, of the opening degree of a brake pedal in a brake energy recovery mode_{Brk_hi}Upper limit value, n, of opening of brake pedal in braking energy recovery mode_BrkIs the lowest rotation speed, v, of the motor MG2 in the braking energy recovery mode_BrkMinimum vehicle speed, soc, required for the braking energy recovery mode_{Brk_hi}The upper limit value of the battery SOC in the braking energy recovery mode;

step 2(b), if the condition for triggering the sliding energy recovery mode in the formula (2) is met, the vehicle enters the sliding energy recovery mode;

in the formula (2), gamma_{Slide_lo}Is the lower limit value of the opening degree of a brake pedal in a coasting energy recovery mode, gamma_{Slide_hi}Upper limit value, n, of opening of brake pedal in coasting energy recovery mode_SlideIs the lowest rotation speed, v, of the motor MG2 in the coasting energy recovery mode_SlideMinimum vehicle speed, soc, required for the coasting energy recovery mode_{Slide_hi}The upper limit value of the battery SOC in the coasting energy recovery mode;

step 2(c), if the two mode triggering conditions are not met, the vehicle enters a non-recovery mode;

step 3, respectively calculating the initial values of the braking energy recovery power of the vehicle under the N gear and the D gear according to the mode of the vehicle in the step 2;

step 3(a), the vehicle is in a braking energy recovery mode, and the initial value P of the braking energy recovery power of the vehicle under the N gear and the D gear_{Brk_reg_N_ini}The opening degree gamma of the brake pedal and the rotation speed n of the motor MG2 are calculated_MG2Obtaining the result by looking up a table;

step 3(b), the vehicle is in a sliding energy recovery mode, and the initial value P of the sliding energy recovery power of the vehicle in the N gear and the D gear_{Slide_reg_N_ini}The motor speed is obtained by looking up a table according to the rotating speed of the motor MG2 and the rotating speed change rate of the motor MG 2;

step 3(c), the vehicle is in a non-recovery mode, and the energy recovery power of the vehicle is 0 at the moment;

step 4, according to the mode of the vehicle in the step 2, considering the influence of the gear and the temperature change of the motor MG2 on the recovery power, respectively calculating the actual values of the braking energy recovery power of the vehicle under the N gear and the D gear;

step 4(a), the vehicle is in a braking energy recovery mode, and the initial value of the braking energy recovery power obtained in the step 3(a) is multiplied by a correction factor obtained by looking up the table of the motor MG2 temperature at the current moment to obtain the actual value of the required braking recovery power under the N gear; namely:

P_{Brk_reg_N}＝P_{Brk_reg_N_ini}×_T······················(3)

in the formula (3), P_{Brk_reg_N}The actual value of the braking recovery power in N gear when the vehicle is in the braking energy recovery mode, P_{Brk_reg_N_ini}The initial value of the braking recovery power under the N gear of the braking energy recovery mode is obtained;_Tis a temperature correction factor;

the method comprises the steps that when a vehicle is in a braking energy recovery mode, a correction amount is added to an initial braking recovery power value under the N gear, and then the sum is multiplied by a correction factor obtained by table look-up of the motor MG2 temperature at the current moment to obtain an actual value of the required braking recovery power under the D gear; namely:

P_{Brk_reg_D}＝(P_{Brk_reg_N_ini}+α_Brk)×_T···················(4)

in the formula (4), P_{Brk_reg_D}The actual value of the braking recovery power in the D gear, P, when the vehicle is in the braking energy recovery mode_{Brk_reg_N_ini}For the initial value of the braking recovery power in the braking energy recovery mode N gear, α_BrkIn order to consider the braking power correction amount of the engine brake when the vehicle is braked with gear under the braking energy recovery mode,_Tis a temperature correction factor;

step 4(b), when the vehicle is in the sliding energy recovery mode, the driver does not operate the brake pedal, and the opening gamma of the brake pedal is 0; multiplying the initial value of the sliding energy recovery power of the vehicle under the N gear by a correction factor obtained by table lookup of the temperature of the motor MG2 at the current moment to obtain an actual value of the required braking recovery power under the N gear; namely:

P_{Slide_reg_N}＝P_{Slide_reg_N_ini}×_T····················(5)

in the formula (5), P_{Slide_reg_N}The actual value of the recovered power in N gear, P, when the vehicle is in the sliding energy recovery mode_{Slide_reg_N_ini}The initial value of the braking recovery power under the sliding energy recovery mode N gear,_Tis a temperature correction factor;

when the vehicle is in a sliding energy recovery mode, adding correction quantity obtained by table lookup according to the rotating speed of MG2 and the rotating speed change rate of the motor MG2 to the initial value of the sliding energy recovery power of the N gear, and multiplying the correction quantity by the correction factor obtained by table lookup of the temperature of the motor MG2 at the current moment to obtain the actual value of the required braking recovery power under the D gear; namely:

P_{Slide_reg_D}＝(P_{Slide_reg_N_ini}+α_Slide)×_T·················(6)

in the formula (6), P_{Slide_reg_D}The actual value of the energy recovery power in the D gear, P, when the vehicle is in the sliding energy recovery mode_{Slide_reg_N_ini}Initial value of energy recovery power for coast energy recovery mode N range, α_SlideConsidering vehicle belts for coasting energy recovery modeThe braking power correction amount of the engine brake at the time of the gear braking,_Tis a temperature correction factor.

Therefore, the invention provides a method for calculating the braking recovery energy of a planetary series-parallel hybrid electric vehicle, which is based on the opening gamma of a brake pedal of the planetary series-parallel hybrid electric vehicle and the rotating speed n of a motor MG2_MG2And judging the energy recovery mode of the current vehicle according to the vehicle speed v and the battery SOC value, and then respectively calculating the braking energy recovery power of the vehicle under the N gear and the D gear according to the mode of the vehicle. According to the method, the influence of engine braking and motor MG2 temperature change on the vehicle braking recovery power when the vehicle is braked in a gear is considered, and reasonable correction quantity and temperature correction factors are set, so that the problems of large error and low precision in the existing planetary hybrid electric vehicle braking recovery energy calculation method are solved, and the accuracy and reliability of vehicle braking energy recovery power calculation can be improved.

Claims (1)

1. A method for calculating braking recovery energy of a planetary series-parallel hybrid electric vehicle is characterized by comprising the following steps: the method comprises the following steps:

step 1, acquiring the opening gamma of a brake pedal and the rotating speed n of a motor MG2 through a sensor_MG2State quantity information such as automobile speed v and battery SOC value;

step 2, according to the opening gamma of a brake pedal of the planetary series-parallel hybrid electric vehicle and the rotating speed n of the motor MG2_MG2Judging the energy recovery mode of the current vehicle according to the vehicle speed v and the battery SOC value;

step 2(a), if the triggering condition of the braking energy recovery mode in the formula (1) is met, the vehicle enters the braking energy recovery mode;

in the formula (1), gamma_{Brk_lo}Is the lower limit value, gamma, of the opening degree of a brake pedal in a brake energy recovery mode_{Brk_hi}Upper limit value, n, of opening of brake pedal in braking energy recovery mode_BrkFor recovering braking energyMinimum speed, v, of motor MG2 in mode_BrkMinimum vehicle speed, soc, required for the braking energy recovery mode_{Brk_hi}The upper limit value of the battery SOC in the braking energy recovery mode;

step 2(b), if the condition for triggering the sliding energy recovery mode in the formula (2) is met, the vehicle enters the sliding energy recovery mode;

in the formula (2), gamma_{Slide_lo}Is the lower limit value of the opening degree of a brake pedal in a coasting energy recovery mode, gamma_{Slide_hi}Upper limit value, n, of opening of brake pedal in coasting energy recovery mode_SlideIs the lowest rotation speed, v, of the motor MG2 in the coasting energy recovery mode_SlideMinimum vehicle speed, soc, required for the coasting energy recovery mode_{Slide_hi}The upper limit value of the battery SOC in the coasting energy recovery mode;

step 2(c), if the two mode triggering conditions are not met, the vehicle enters a non-recovery mode;

step 3, respectively calculating the initial values of the braking energy recovery power of the vehicle under the N gear and the D gear according to the mode of the vehicle in the step 2;

step 3(a), the vehicle is in a braking energy recovery mode, and the initial value P of the braking energy recovery power of the vehicle under the N gear and the D gear_{Brk_reg_N_ini}The opening degree gamma of the brake pedal and the rotation speed n of the motor MG2 are calculated_MG2Obtaining the result by looking up a table;

step 3(b), the vehicle is in a sliding energy recovery mode, and the initial value P of the sliding energy recovery power of the vehicle in the N gear and the D gear_{Slide_reg_N_ini}The motor speed is obtained by looking up a table according to the rotating speed of the motor MG2 and the rotating speed change rate of the motor MG 2;

step 3(c), the vehicle is in a non-recovery mode, and the energy recovery power of the vehicle is 0 at the moment;

step 4, according to the mode of the vehicle in the step 2, considering the influence of the gear and the temperature change of the motor MG2 on the recovery power, respectively calculating the actual values of the braking energy recovery power of the vehicle under the N gear and the D gear;

step 4(a), the vehicle is in a braking energy recovery mode, and the initial value of the braking energy recovery power obtained in the step 3(a) is multiplied by a correction factor obtained by looking up the table of the motor MG2 temperature at the current moment to obtain the actual value of the required braking recovery power under the N gear; namely:

P_{Brk_reg_N}＝P_{Brk_reg_N_ini}×_T························(3)

in the formula (3), P_{Brk_reg_N}The actual value of the braking recovery power in N gear when the vehicle is in the braking energy recovery mode, P_{Brk_reg_N_ini}The initial value of the braking recovery power under the N gear of the braking energy recovery mode is obtained;_Tis a temperature correction factor;

the method comprises the steps that when a vehicle is in a braking energy recovery mode, a correction amount is added to an initial braking recovery power value under the N gear, and then the sum is multiplied by a correction factor obtained by table look-up of the motor MG2 temperature at the current moment to obtain an actual value of the required braking recovery power under the D gear; namely:

P_{Brk_reg_D}＝(P_{Brk_reg_N_ini}+α_Brk)×_T·····················(4)

in the formula (4), P_{Brk_reg_D}The actual value of the braking recovery power in the D gear, P, when the vehicle is in the braking energy recovery mode_{Brk_reg_N_ini}For the initial value of the braking recovery power in the braking energy recovery mode N gear, α_BrkIn order to consider the braking power correction amount of the engine brake when the vehicle is braked with gear under the braking energy recovery mode,_Tis a temperature correction factor;

step 4(b), when the vehicle is in the sliding energy recovery mode, the driver does not operate the brake pedal, and the opening gamma of the brake pedal is 0; multiplying the initial value of the sliding energy recovery power of the vehicle under the N gear by a correction factor obtained by table lookup of the temperature of the motor MG2 at the current moment to obtain an actual value of the required braking recovery power under the N gear; namely:

P_{Slide_reg_N}＝P_{Slide_reg_N_ini}×_T······················(5)

in the formula (5), P_{Slide_reg_N}For vehicles inIn the sliding energy recovery mode, the actual value of the recovered power in N gear, P_{Slide_reg_N_ini}The initial value of the braking recovery power under the sliding energy recovery mode N gear,_Tis a temperature correction factor;

when the vehicle is in a sliding energy recovery mode, adding correction quantity obtained by table lookup according to the rotating speed of MG2 and the rotating speed change rate of the motor MG2 to the initial value of the sliding energy recovery power of the N gear, and multiplying the correction quantity by the correction factor obtained by table lookup of the temperature of the motor MG2 at the current moment to obtain the actual value of the required braking recovery power under the D gear; namely:

P_{Slide_reg_D}＝(P_{Slide_reg_N_ini}+α_Slide)×_T···················(6)

in the formula (6), P_{Slide_reg_D}The actual value of the energy recovery power in the D gear, P, when the vehicle is in the sliding energy recovery mode_{Slide_reg_N_ini}Initial value of energy recovery power for coast energy recovery mode N range, α_SlideIn order to consider the braking power correction amount of the engine brake when the vehicle is braked with gear under the coasting energy recovery mode,_Tis a temperature correction factor.

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