CN104477040B - Monoergic source electric car time-dependent current regenerating brake control method - Google Patents
Monoergic source electric car time-dependent current regenerating brake control method Download PDFInfo
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Abstract
The invention discloses a kind of monoergic source electric car time-dependent current regenerating brake control method, comprise the steps: 1) can determine that motor maximum braking torque according to Vehicle Speed, electric moter voltage and electric current, thus can obtain armature electric current；2) control system carries out the identification of regenerative braking time；3) the maximum acceptable charging current of battery is determined based on the braking time identified；4) based on the severity of braking reasonable distribution mechanical braking force identified and motor braking power；5) by comparing motor regenerative brake current and battery acceptable charging current, regenerative braking feedback current is obtained；6) along with the reduction of speed, the constantly maximum feedback current of conversion, dynamic following acceptable charging current.The invention has the beneficial effects as follows: the present invention, with feedback current as control object, takes into account battery charging safety and system protection, farthest improves energy recovery efficiency.
Description
Technical field
The present invention relates to the control method of electric vehicle brake, particularly relate to a kind of monoergic source electric car time-dependent current regenerative braking
The method controlled.
Background technology
Electric automobile is main with battery as power source, completely or partially by the automobile of motor-driven, relates to machinery, electricity
The multi-disciplinary high-tech technical products such as son, electric power, microcomputer control.In recent years, the research and development of electric automobile present in countries in the world
Going out the trend of accelerated development, each state is all actively promoting the development of electric automobile.
Electric automobile is that electric automobile can realize regenerative braking with a most important difference of conventional fuel oil automobile, reclaims one
Divide the energy that conventional fuel oil automobile loses in braking procedure, thus improve the continual mileage of electric automobile.For monoergic source electricity
Electrical automobile, regenerating braking energy can only feed back to battery.In order to maximize feeding braking energy back, prior art uses maximum feedback
The regenerative braking methods such as power braking, maximum feedback efficiency braking, constant moment braking and constant charge current braking.But with
Upper method does not accounts for the restriction of battery charge mostly, and battery can be caused damage by excessive feedback current.To this end, it is right
During monoergic source electric car braking energy feedback, the restriction of battery charging current should be considered, ensure electric power storage
On the premise of the safe charging of pond, maximize and reclaim braking energy.
Summary of the invention
It is an object of the invention to overcome the deficiencies in the prior art, it is provided that one considers motor braking control collaborative with mechanical braking
System, it is ensured that on the premise of battery reliably charges, to greatest extent the monoergic source electric car time-dependent current regeneration of feeding braking energy back
Brake control method.
This monoergic source electric car time-dependent current regenerating brake control method, comprises the steps:
1), during electric vehicle brake, can determine that motor maximum braking torque according to Vehicle Speed, electric moter voltage and electric current,
Thus can obtain motor regenerative brake current；
2) control system gathers brake pedal force, pedal displacement variable quantity, pedal displacement rate of change in braking procedure by sensor
And speed carries out the identification of regenerative braking time；
3) battery SOC, voltage and temperature information are obtained by battery management system, according to battery charge model, based on
The regenerative braking time identified determines the maximum acceptable charging current of battery；
4) based on the severity of braking reasonable distribution mechanical braking force identified and motor braking power；
5) by comparing motor regenerative brake current and the maximum acceptable charging current of battery, regenerative braking feedback current is obtained；
6) along with the reduction of speed, constantly conversion regenerative braking feedback current, dynamic following acceptable charging current, take into account battery
Charging safety and system protection, maximize feeding braking energy back.
As preferably: in described step 2, model training and identification are separated and independently performed；The input of braking action model is seen
Order-checking row obtained by vehicle road test, after the data that each sensor gathers necessarily are pre-processed, brake model is carried out from
Line training and identification checking.
As preferably: the maximum acceptable charging current of battery in described step 3, use mixed pulses power characteristic method of testing
HPPC tests battery charging and discharging internal resistance, and by being calculated.
As preferably: in described step 4, the control with changed scale hydraulic valve optimized distribution line is used to replace ideal braking force distribution bent
Line, is provided brake force as far as possible many being assigned in drive shaft by motor braking.
As preferably: in described step 5, when motor regenerative brake current more than battery maximum acceptable charging current time, then by
The maximum acceptable charging current of battery is as regenerative braking feedback current；When motor regenerative brake current is maximum acceptable less than battery
During charging current, then by motor regenerative brake current as regenerative braking feedback current.
As preferably: described step 6 uses converting charge method that constant-current charge section changes into pressure limiting time-dependent current charging section, each rank of charging
The acceptable maximum charging current of Duan Caiyong, it is thus achieved that overwhelming majority charge volume.
The invention has the beneficial effects as follows: the present invention, with feedback current as control object, takes into account battery charging safety and system protection,
Farthest improve energy recovery efficiency, design for Control Strategy for Regenerative Braking and provide a kind of new optimization method.
Accompanying drawing explanation
Fig. 1 is monoergic source electric car unsteady flow regenerative braking control flow chart of the present invention；
Fig. 2 is regenerative braking time identification process figure of the present invention；
Fig. 3 is maximum charging current curve map under certain battery different condition；
Fig. 4 is regenerative braking front and back wheel braking force distribution schematic diagram of the present invention；
Fig. 5 is regenerative braking hierarchical coordinative control flow chart of the present invention；
Fig. 6 is the regenerative braking feedback current of the present invention change curve with speed.
Detailed description of the invention
With embodiment, the present invention is described further below in conjunction with the accompanying drawings.Although the present invention will be described in conjunction with preferred embodiment,
It should be understood that be not offered as limiting the invention in described embodiment.On the contrary, the present invention will contain and can be included in attached right
Alternative, modified and equivalent in the scope of the present invention that claim limits.
The technical solution used in the present invention is when electric automobile regenerative braking, according to Vehicle Speed, electric moter voltage and electric current
Can determine that motor maximum braking torque；Using brake pedal force, pedal displacement variable quantity, pedal displacement rate of change and speed as
Input observed value, accurately identified the regenerative braking time.Meanwhile, battery SOC, voltage are obtained by battery management system
With the information such as temperature, based on the braking time identified, provide severity of braking and obtain the maximum acceptable charging current of battery.According to
Severity of braking rational distribution machinery brake force and motor braking power, can connect by comparing motor regenerative brake current and battery maximum
By charging current, determine regenerative braking feedback current, thus the regenerative braking moment of accurate offer demand.Take into account motor
The big factor such as braking power and battery charging ability, reclaims braking energy to greatest extent.
The control of the present invention uses hierarchical coordinative control strategy that brakes is divided into upper and lower two-layer, and upper strata is motor braking control,
Lower floor is mechanical braking control.Motor braking controls to be realized by armature supply and the acceptable charging current dynamically followed the tracks of, and will
The demand of motor braking power is converted into the control to mechanical braking.By determining in real time charging current, it is achieved upper strata motor system
The dynamic unified regulation with lower floor's mechanical braking, had both avoided overcharging of battery, had achieved again the stability of braking.
In process of regenerative braking, braking time and identifying of severity of braking are first trained correspondence by a large amount of observation sequences collected
Model, reapplies the model trained and is identified process.The input observation sequence of braking action model is obtained by vehicle road test
, after the data that each sensor gathers necessarily being pre-processed, braking action model is carried out off-line training and identification checking.
Braking energy feedback uses converting charge method that constant-current charge section changes into pressure limiting time-dependent current charging section, and each stage of charging uses can
The maximum charging current accepted, it is thus achieved that overwhelming majority charge volume.
As it is shown in figure 1, monoergic source electric car unsteady flow regenerating brake control method of the present invention comprises the following steps:
(1), during electric vehicle brake, can determine that the braking of motor maximum turns according to Vehicle Speed, electric moter voltage and electric current
Square, thus can obtain motor regenerative brake current.Even if generally time relatively low, the biggest charging current also can be produced at motor speed ratio,
Battery can be caused damage by these electric currents often beyond the maximum charging current of battery, excessive electric current.
(2) control system gathers brake pedal force in braking procedure, pedal displacement variable quantity, pedal displacement change by sensor
Rate and speed carry out the identification of regenerative braking time.In the electric automobile being configured with braking energy feedback technology, mechanical braking
Being existence, associated working simultaneously with motor braking, the requirement of braking time is different because of damped condition.
Use the mode of statistical-simulation spectrometry, regenerative braking is intended to and the time identifies and is analyzed on different time scales,
In different layers, the simple motion to different time scales is modeled, as shown in Figure 2 respectively.With brake pedal in ground floor model
Power, pedal displacement variable quantity, pedal displacement rate of change and speed are as input observed value, in braking action identification process,
Choose the maximum model of likelihood score as the braking action result identified, itself and speed grade are carried out symbolism, as second
The list entries of layer, more therefrom choose the maximum model of likelihood score as the braking time identified and intensity.
(3) information such as battery SOC, voltage and temperature are obtained by battery management system, according to battery charge model, base
The braking time identified in step 2 determines the maximum acceptable charging current of battery.The internal resistance phase of the charging ability of battery and battery
Closing, the internal resistance of battery is a dynamic value, with changes such as the temperature residing for battery, state-of-charge SOC and working current values
Difference, that reflects fundamental characteristics and the ability of battery.Use mixed pulses power characteristic method of testing HPPC can test electricity
Pond discharge and recharge internal resistance, if the operating voltage of battery is limited to u up and downmin≤u(t)≤umax, then can be calculated what battery allowed
Maximum charging current isFig. 3 show maximum charging current under certain battery different condition
Curve map, as seen from the figure, under conditions of temperature is identical with SOC, battery maximum charging current is relevant with charging interval length,
Charging interval is the shortest, and the current limit value that can bear is the biggest.It addition, battery can accept the increase being filled with electric current with SOC value
And reduce, when SOC value is more than 0.9, then forbid charging the battery.Meanwhile, battery charge variation with temperature compares
Substantially, the highest chargeable electric current of temperature is the biggest, owing to large current charge can produce bigger fuel factor, to normal battery operation not
Profit, therefore, should avoid when temperature is higher than 55 DEG C using regenerative braking.
(4) the severity of braking reasonable distribution mechanical braking force identified according to step 2 and motor braking power.During electric vehicle brake,
The only energy on driving wheel can be recovered, therefore, in order to maximize recovery braking energy, it is necessary to by the most systems
Power distributes to driving wheel；But then, in order to ensure the automobile stability when braking, the braking of front and rear wheel is required again
Power distribution must is fulfilled for certain requirement.Therefore, maximizing braking force distribution is on the premise of realizing automobile braking safety,
Use regenerative braking as much as possible.
Electric automobile to front-wheel drive, uses braking force distribution control line as shown in Figure 4.In figure, thick broken line OABCD is
Front and rear wheel braking force distribution limit value control line.When severity of braking is less, front-wheel provide whole brake force (OA section)；
When severity of braking is bigger, front and rear wheel jointly providing brake force (AB section and BC section), wherein AB section is M curve
Tangent line, BC section is parallel with f line and brake force is f line 90%；When severity of braking is more than C point, braking force distribution is pressed
CD section carries out until f line and I intersections of complex curve.
(5) by the maximum acceptable charged electrical of battery comparing the motor regenerative brake current determined by step 1 and step 3 determines
Stream, obtains regenerative braking feedback current.
If 1. motor regenerative brake current is more than the maximum acceptable charging current of battery, then by the maximum acceptable charging current of battery
As regenerative braking feedback current；
If 2. motor regenerative brake current is less than the maximum acceptable charging current of battery, then by motor regenerative brake current as again
Raw feedback braking electric current.
Motor braking controls and mechanical braking controls to have identical control variables, i.e. regenerative braking force, and motor braking control is
Realized by the control of feedback current.When motor braking and mechanical braking Collaborative Control, dynamic by feedback current
Follow the tracks of and determine in real time, the control target of regenerative braking force is coordinated unification, as shown in Figure 5.Control system is in satisfied system
On the premise of dynamic security and battery charging reliably, preferentially using motor braking, insufficient section is provided by mechanical braking, thus real
Existing maximized energy feedback.
(6) along with the reduction of speed, motor back emf declines, and causes armature supply persistently to rise.When armature supply rises
To when being unsatisfactory for requiring, now, the setting value of maximum charging current can not be reduced according to maximum feedback current charging,
Continue feedback energy, as shown in Figure 6.When motor speed drops to 500r/min, the counter electromotive force that motor produces is the least,
Now being difficult to charge the battery, regenerative braking lost efficacy, and used hydraulic braking completely.
Claims (3)
1. a monoergic source electric car time-dependent current regenerating brake control method, it is characterised in that: comprise the steps:
1), during electric vehicle brake, can determine that motor maximum braking torque according to Vehicle Speed, electric moter voltage and electric current,
Thus can obtain motor regenerative brake current；
2) control system gathers brake pedal force, pedal displacement variable quantity, pedal displacement rate of change in braking procedure by sensor
And speed carries out the identification of regenerative braking time；
3) battery SOC, voltage and temperature information are obtained by battery management system, according to battery charge model, based on knowledge
The regenerative braking time not gone out determines the maximum acceptable charging current of battery；
4) based on the severity of braking reasonable distribution mechanical braking force identified and motor braking power；
5) by comparing motor regenerative brake current and the maximum acceptable charging current of battery, regenerative braking feedback current is obtained；
6) along with the reduction of speed, constantly conversion regenerative braking feedback current, dynamic following acceptable charging current, take into account battery
Charging safety and system protection, maximize feeding braking energy back；
Described step 2) in model training and identify be separated and independently performed；The input observation sequence of braking action model is by reality
Car actual road test obtains, and after the data that each sensor gathers necessarily being pre-processed, brake model carries out off-line training and distinguishes
Know checking.
Monoergic source electric car time-dependent current regenerating brake control method the most according to claim 1, it is characterised in that: institute
The step 3 stated) in the maximum acceptable charging current of battery, use mixed pulses power characteristic method of testing HPPC test battery fill
Electric discharge internal resistance, and by being calculated.
Monoergic source electric car time-dependent current regenerating brake control method the most according to claim 1, it is characterised in that: institute
State step 6) in use converting charge method that constant-current charge section changes into pressure limiting time-dependent current charging section, each stage of charging uses acceptable
Maximum charging current, it is thus achieved that the overwhelming majority charge volumes.
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| US11801754B1 (en) * | 2022-12-15 | 2023-10-31 | Mercedes-Benz Group AG | System, device, and/or process for determining motor driver safety state for electric vehicle |
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