阅读说明：本技术 一种纯电动汽车回馈力矩根据减速度调整的方法 (Method for adjusting feedback torque of pure electric vehicle according to deceleration ) 是由 蔡振兴 赵春明 周能辉 李磊 杜森 翟世欢 于 2020-07-23 设计创作，主要内容包括：本发明公开了一种纯电动汽车回馈力矩根据减速度调整的方法,包括以下步骤：整车控制器通过制动开关状态,区分出车辆的制动回馈与滑行回馈状态。整车控制器对汽车当前瞬时速度查表得出回馈力矩标准值。通过汽车当前瞬时速度,计算出额定时间车辆的平均减速度；通过汽车当前瞬时速度,查表得出当前状态期望减速度；通过平均减速度与期望减速度倍数关系,进行查表得出回馈力矩系数步长调整值。回馈力矩系数对步长调整值进行累加,得出实时回馈力矩系数。回馈力矩标准值与回馈力矩系数的乘积作为回馈力矩值指令。此方法,实现对回馈力矩的闭环控制,在保证车辆电制动的同时,提高了车辆满载或下坡状态下的能量回收。(The invention discloses a method for adjusting feedback torque of a pure electric vehicle according to deceleration, which comprises the following steps: the vehicle control unit distinguishes braking feedback and sliding feedback states of the vehicle according to the braking switch state. And the vehicle control unit looks up the current instantaneous speed of the vehicle to obtain a feedback torque standard value. Calculating the average deceleration of the vehicle at the rated time according to the current instantaneous speed of the vehicle; looking up a table to obtain the expected deceleration of the current state according to the current instantaneous speed of the automobile; and looking up a table to obtain a feedback moment coefficient step length adjusting value through the relation between the average deceleration and the expected deceleration multiple. And accumulating the step length adjusting values by the feedback moment coefficient to obtain a real-time feedback moment coefficient. And taking the product of the feedback torque standard value and the feedback torque coefficient as a feedback torque value instruction. The method realizes closed-loop control of the feedback torque, ensures electric braking of the vehicle and improves energy recovery of the vehicle in a full load or downhill state.)

1. A method for adjusting feedback torque of a pure electric vehicle according to deceleration is characterized by comprising the following steps:

the method comprises the steps that firstly, if the vehicle control unit judges that the pure electric vehicle is in a feedback state and the pure electric vehicle is provided with a brake switch, the vehicle is judged to be in a brake feedback state; otherwise, judging that the automobile is in a sliding feedback state;

secondly, if the automobile is in a brake feedback state, the whole automobile controller looks up a table according to the current instantaneous speed of the automobile to obtain a brake feedback torque standard value; if the automobile is in a sliding feedback state, the whole automobile controller looks up a table according to the current instantaneous speed of the automobile to obtain a sliding feedback torque standard value;

thirdly, the vehicle controller passes through the vehicle instantaneous speed V within the set rated time T_iCalculating the average speed V of the automobile in the rated time_aveThe formula is as follows:

fourthly, calculating the deceleration A of the vehicle running at the nth T time, wherein the formula is as follows:

A＝(V_ave2-V_ave1)/T；

wherein V_ave2Average speed, V, for the vehicle operating at time (n-2) T_ave1The average speed of the automobile running at the (n-1) th T time; t is in the unit of s;

fifthly, the vehicle control unit obtains the expected deceleration of the current state by looking up a table according to the instantaneous speed of the vehicle; obtaining a multiple value by dividing the deceleration calculated by the vehicle by the expected deceleration, and obtaining a real-time feedback moment coefficient step length adjusting value delta K by looking up a table of the multiple value;

sixthly, defining the real-time feedback moment coefficient as K and the initial value as 1; the vehicle control unit accumulates the real-time feedback torque coefficient step length adjustment value obtained in the fifth step through a formula K which is K plus delta K on the basis of the real-time feedback torque coefficient initial value 1 to obtain a real-time feedback torque coefficient;

and seventhly, the vehicle controller takes the brake feedback torque standard value or the product of the sliding feedback torque standard value and the real-time feedback torque coefficient as a feedback torque value instruction, the feedback torque value instruction is sent to a motor controller of the pure electric vehicle, and the motor controller controls the motor to perform feedback.

Technical Field

The invention relates to a method for adjusting feedback torque of a pure electric vehicle, in particular to a method for adjusting the feedback torque of the pure electric vehicle according to deceleration.

Background

In the existing feedback strategy of the pure electric vehicle, the calculation of feedback torque control is relatively single, and feedback is mainly carried out according to vehicle parameters, vehicle speed and the like. The working conditions of the vehicle cannot be distinguished when the vehicle is fully loaded, unloaded, uphill and downhill. Resulting in failure to provide sufficient regenerative torque when large brake feedback is required during full load or downhill.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a method for adjusting feedback torque of a pure electric vehicle according to deceleration, so that closed-loop control over the feedback torque is realized, and energy recovery in a full-load or downhill state of the vehicle is improved while electric braking of the vehicle is ensured.

The invention discloses a method for adjusting feedback torque of a pure electric vehicle according to deceleration, which comprises the following steps of:

the method comprises the steps that firstly, if the vehicle control unit judges that the pure electric vehicle is in a feedback state and the pure electric vehicle is provided with a brake switch, the vehicle is judged to be in a brake feedback state; otherwise, judging that the automobile is in a sliding feedback state;

secondly, if the automobile is in a brake feedback state, the whole automobile controller looks up a table according to the current instantaneous speed of the automobile to obtain a brake feedback torque standard value; if the automobile is in a sliding feedback state, the whole automobile controller looks up a table according to the current instantaneous speed of the automobile to obtain a sliding feedback torque standard value;

thirdly, the vehicle controller passes through the vehicle instantaneous speed V within the set rated time T_iCalculating the average speed V of the automobile in the rated time_aveThe formula is as follows:

wherein m is a scheduling period of the program operation of the T/vehicle controller;

fourthly, calculating the deceleration A of the vehicle running at the nth T time, wherein the formula is as follows:

A＝(V_ave2-V_ave1)/T；

wherein V_ave2Average speed, V, for the vehicle operating at time (n-2) T_ave1The average speed of the automobile running at the (n-1) th T time; t is in the unit of s;

fifthly, the vehicle control unit obtains the expected deceleration of the current state by looking up a table according to the instantaneous speed of the vehicle; obtaining a multiple value by dividing the deceleration calculated by the vehicle by the expected deceleration, and obtaining a real-time feedback moment coefficient step length adjustment value delta K by looking up a table of the multiple value;

sixthly, defining the real-time feedback moment coefficient as K and the initial value as 1; the vehicle control unit accumulates the real-time feedback torque coefficient step length adjustment value obtained in the fifth step through a formula K which is K plus delta K on the basis of the real-time feedback torque coefficient initial value 1 to obtain a real-time feedback torque coefficient;

and seventhly, the vehicle controller takes the brake feedback torque standard value or the product of the sliding feedback torque standard value and the real-time feedback torque coefficient as a feedback torque value instruction, the feedback torque value instruction is sent to a motor controller of the pure electric vehicle, and the motor controller controls the motor to perform feedback.

The invention has the advantages that: the closed-loop control of the feedback torque is realized, and the energy recovery of the vehicle in a full load or downhill state is improved while the electric braking of the vehicle is ensured.

Detailed Description

In order to better explain the contents, features and effects of the present invention, the following embodiments are described in detail.

The invention discloses a method for adjusting feedback torque of a pure electric vehicle according to deceleration, which comprises the following steps of:

firstly, if the vehicle control unit judges that the pure electric vehicle is in a feedback state (the judging method adopts the prior art, such as an entering feedback method disclosed in electric vehicle motor energy feedback strategy analysis published in the college of Hankou 2016), and the pure electric vehicle is provided with a brake switch, the vehicle control unit judges that the pure electric vehicle is in a brake feedback state; otherwise, judging that the automobile is in a sliding feedback state;

secondly, if the automobile is in a brake feedback state, the whole automobile controller looks up a table according to the current instantaneous speed of the automobile to obtain a brake feedback torque standard value; and if the automobile is in a sliding feedback state, the whole automobile controller looks up a table according to the current instantaneous speed of the automobile to obtain a sliding feedback torque standard value.

Thirdly, the vehicle controller modifies the program parameters through an upper computer by adopting a method which is commonly used in the current automobile industry, such as CCP, XCP and the like, within the set rated time T (which can be calibrated and adopts the method for correcting the program parameters) to obtain the instantaneous speed V of the vehicle_iCalculating the average speed V of the automobile in the rated time_aveThe formula is as follows:

wherein m is a scheduling period of the program operation of the T/vehicle controller;

fourthly, calculating the deceleration A of the vehicle running at the nth T time, wherein the formula is as follows:

A＝(V_ave2-V_ave1)/T；

wherein V_ave2Average speed, V, for the vehicle operating at time (n-2) T_ave1The average speed of the automobile running at the (n-1) th T time; t is in the unit of s;

fifthly, the vehicle controller obtains the current state expected deceleration (which can be calibrated) by looking up a table according to the instantaneous speed of the vehicle; a multiple value is obtained by dividing the deceleration calculated by the vehicle by the expected deceleration, and a real-time feedback moment coefficient step length adjusting value delta K (which can be calibrated) is obtained by looking up a table of the multiple value.

And sixthly, defining the real-time feedback moment coefficient as K and the initial value as 1. And accumulating the real-time feedback torque coefficient step length adjustment value obtained in the fifth step by a formula K which is K plus delta K on the basis of the real-time feedback torque coefficient initial value 1 to obtain the real-time feedback torque coefficient.

And seventhly, the vehicle controller takes the brake feedback torque standard value or the product of the sliding feedback torque standard value and the real-time feedback torque coefficient as a feedback torque value instruction, the feedback torque value instruction is sent to a motor controller of the pure electric vehicle, and the motor controller controls the motor to perform feedback.