CN209198628U - A kind of power battery of pure electric automobile state-of-charge estimating system - Google Patents
A kind of power battery of pure electric automobile state-of-charge estimating system Download PDFInfo
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- CN209198628U CN209198628U CN201821692611.7U CN201821692611U CN209198628U CN 209198628 U CN209198628 U CN 209198628U CN 201821692611 U CN201821692611 U CN 201821692611U CN 209198628 U CN209198628 U CN 209198628U
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Abstract
The utility model relates to electric automobile power battery technologies, and in particular to a kind of power battery of pure electric automobile state-of-charge estimating system, including power battery, data acquisition module, battery SOC estimation module, main control module and LCD display；Main control module is separately connected power battery, battery SOC estimation module and LCD display, and power battery is sequentially connected data acquisition module, and data acquisition module is connect with battery SOC estimation module.The system can solve the problems, such as power battery SOC estimation accuracy it is not high recognize with real-time parameter single-chip microcontroller is required it is excessively high.Common mode interference can be effectively eliminated, circuit is simple, and largely reduces calculation amount, to reduce battery management system cost, the problem of self-discharge of battery when also solving static and ampere-hour method can not be measured.
Description
Technical field
The utility model belongs to electric automobile power battery technical field more particularly to a kind of power battery of pure electric automobile
State-of-charge estimating system.
Background technique
The critically important a part of electric automobile power battery management system (BMS) is exactly battery charge state (SOC, State
Of Charge) estimation, accuracy directly affects the control strategy of battery management system, is to guarantee that electric car is reliably transported
Capable premise.Further, battery charge state estimation needs to establish accurate battery model, carries out circuit point on this basis
Analysis and algorithms selection.And difficult point is that battery has the non-linear behavior of height, so battery model and power battery
Consistency will reach very good, can just obtain satisfactory battery charge state estimated result.Currently, common power battery
Model has three classes: electrochemical model, artificial nerve network model and equivalent-circuit model.Electrochemical model is because structure is excessively multiple
Miscellaneous, practicability is poor, therefore is rarely used in battery charge state estimation；Artificial nerve network model have height it is non-linear, from
The features such as property learned, but disadvantage is that need a large amount of experimental data to predict the performance of battery, and to battery history number
According to dependence it is larger；Equivalent-circuit model forms circuit network by circuit elements such as traditional resistance, capacitor, constant pressure sources
The external characteristics for describing power battery, since its structure is relatively easy and can preferably describe battery behavior, examining in cost performance
Consider, researcher often selects the model.On the basis of selected power battery model, power battery SOC estimation method mainly has: opening
Road voltage method, current integration method, Kalman filtering method.Open circuit voltage method can only realize offline estimation in laboratory conditions, no
It can real-time estimation；Current integration method classics are easy-to-use, but its estimated accuracy by the precision of SOC initial value and current measurement value influenced compared with
Greatly, accumulated error easy to form；And kalman filter method has preferable tracing property, can more accurately predict SOC value,
It is that battery SOC estimates the most commonly used method of research.It specifically has Extended Kalman filter, Unscented kalman filtering, adaptive
The types such as Kalman filtering.
But existing battery SOC estimation has the following problems:
1. voltage collection circuit can not collect accurate end voltage；
2. parameter identification division is excessively high to single-chip microcontroller requirement, calculation amount needed for online recognition is very huge；
3. charge and discharge phenomenon easily occurred in battery, battery is damaged；
4. after stopping for a long time when restarting, self-discharge processes can not be detected by ampere-hour method, thus SOC be estimated to be it is larger
Error.
Utility model content
The purpose of the utility model is to provide one kind by carrying out off-line identification battery model parameter again under certain condition
The system for carrying out SOC state value Combined estimator by Extended Kalman filter.
In order to achieve the above purposes, the technical solution adopted by the utility model is:, and a kind of power battery of pure electric automobile is charged
Condition estimating system, including power battery, data acquisition module, battery SOC estimation module, main control module and LCD display；It is main
Control module is separately connected power battery, battery SOC estimation module and LCD display, power battery and is sequentially connected data acquisition module
Block, data acquisition module are connect with battery SOC estimation module.
In above-mentioned power battery of pure electric automobile state-of-charge estimating system, data acquisition module includes based on " winged
Voltage collection circuit, the large capacity high-precision hall current sensor, thermocouple temperature sensor of capacitor " technology, are respectively used to
Acquire end voltage, total current and the temperature data of power battery.
In above-mentioned power battery of pure electric automobile state-of-charge estimating system, data acquisition module includes based on " winged
The voltage collection circuit of capacitor " technology selects the AQS225R2S4 of Panasonic company.
In above-mentioned power battery of pure electric automobile state-of-charge estimating system, battery SOC estimation module is using mixing
Pulse testing carries out offline parameter identification to batteries of electric automobile equivalent-circuit model, in certain cycle life and certain temperature model
Think parameter constant in enclosing and be input to model parameter to estimate to correct in power battery SOC estimation module；It estimates that correction is adopted
Combined with open circuit voltage method, current integration method and Extended Kalman filter method and battery SOC is estimated and is corrected, obtains electricity
Pond SOC is output to main control module after judging using logic judgment module.
In above-mentioned power battery of pure electric automobile state-of-charge estimating system, main control module is connected to battery SOC and estimates
Module is counted, with the progress of control parameter identification and Kalman Filter Estimation；Main control module is connected on power battery simultaneously, is used for
The charge and discharge output power of power battery is controlled according to the output valve of battery SOC estimation module to protect over-charging of battery to discharge；It is main
Control module is connected with LCD display by CAN bus, shows remaining capacity by LCD display.
In above-mentioned power battery of pure electric automobile state-of-charge estimating system, power battery is LiFePO4 Soft Roll electricity
Pond or ternary lithium battery.
The utility model has the beneficial effects that being based on the voltage of " winged capacitor " technology compared to traditional tension measuring circuit
Measuring circuit does not have isolated power supply, can effectively eliminate common mode interference, and circuit is simple, realizes that reliability is opposite and is easier to.Simultaneously
It does not need sampling hold circuit, under multiple signals simultaneously sampling condition, can be very easy to realize yet.
Off-line identification battery model parameter can reduce calculation amount largely to reduce battery management system cost, but its
There is the cycle life and temperature range being applicable in off-line calculation process, specifically answer reference battery life curve and polarization
Resistance and temperature curve；There are logic judgment module in battery SOC estimation module, preset function includes stopping for a long time
After judge SOC value using open circuit voltage method and be output to LCD display when restarting, battery when this function can solve static
The problem of self discharge and ampere-hour method can not be measured.
Detailed description of the invention
Fig. 1 is a kind of structure of power battery of pure electric automobile state-of-charge estimating system of the utility model one embodiment
Schematic diagram；
Fig. 2 is that a kind of winged capacitance voltage of power battery of pure electric automobile state-of-charge estimating system of the utility model acquires
Functional block diagram；
Fig. 3 is a kind of parameter of power battery of pure electric automobile state-of-charge estimating system of the utility model one embodiment
Identification circuit schematic diagram；
Fig. 4 is a kind of extension of power battery of pure electric automobile state-of-charge estimating system of the utility model one embodiment
Kalman filter theory figure.
Specific embodiment
The embodiments of the present invention is described in detail with reference to the accompanying drawing.
The present embodiment provides a kind of raw data acquisition is more accurate, recognized with offline parameter based on, open circuit voltage method, peace
When integration method and kalman filter method triple combination estimate SOC power battery of pure electric automobile management system.The present embodiment
Can solve the problems, such as power battery SOC estimation accuracy it is not high recognize with real-time parameter single-chip microcontroller is required it is excessively high.
Power battery of pure electric automobile state-of-charge estimating system provided by the utility model, the system include power electric
Pond, data acquisition module, battery SOC estimation module, main control module and LCD display；Main control module is estimated with battery SOC respectively
Module, power battery and LCD display are connected, and power battery connects data acquisition module, and data acquisition module connects battery
SOC estimation module.
Moreover, power battery is the common lithium iron phosphate flexible package battery of electric car or ternary lithium battery.
Moreover, data acquisition module uses the end electricity of the voltage collection circuit acquisition power battery based on " winged capacitor " technology
Pressure, large capacity high-precision hall current sensor acquire total current, thermocouple temperature sensor temperature collection data, and will adopt
The data information collected is sent to battery SOC estimation module.
Moreover, battery SOC estimation module uses open circuit voltage method, current integration method and Extended Kalman filter method three
Combine and battery charge state is estimated and is corrected and is output to main control module.
Moreover, battery SOC estimation module includes a logic judgment module, for judge whether to start to carry out estimation and
Whether parameter area is reasonable.
Moreover, main control module is connected with LCD display by CAN bus, remaining capacity is shown by LCD display.
When it is implemented, as shown in Figure 1, a kind of power battery of pure electric automobile state-of-charge estimating system, including power
Battery, data acquisition module, battery SOC estimation module, main control module and LCD display.Data acquisition module is by the number of acquisition
According to battery SOC estimation module is transmitted to, battery SOC estimation module is tested using mixed pulses to batteries of electric automobile equivalent circuit
Model carries out offline parameter identification, and parameter constant and model parameter is defeated is thought in certain cycle life and certain temperature range
Enter into power battery SOC estimation module estimation correction and obtains battery SOC；Main control module connects battery SOC module, and by battery
SOC estimated result is shown on LCD display, while connecting power battery, and the charge and discharge of power battery are controlled according to output valve
Output power.
As shown in Fig. 2, Panasonic company may be selected in voltage collection circuit this system based on " winged capacitor " technology
AQS225R2S4 selects multichannel photoelectrical coupler.The coupler can support the load voltage of ceiling voltage 80V, compare common simulation
Switch it is much higher, conducting resistance be less than common analog switch, can satisfy high-voltage lithium group channel selection switch sampling
The requirement of rate.It is connected to measuring circuit by coupler, passes sequentially through differential amplifier circuit and absolute value and filter circuit, finally
It is connected to single-chip microcontroller and carries out A/D sampling.
Voltage collection circuit is connected with battery two-port；Large capacity high-precision hall current sensor string is in battery bus；
Thermocouple temperature sensor is placed in inside battery；End voltage, total current and the temperature data of power battery are collected respectively, and
Collected data information is sent to battery SOC estimation module.
The result of battery SOC estimation module is transmitted on LCD display and shows by main control module, while according to battery SOC
The charge and discharge output power of the output valve control power battery of estimation module.
Specific introduction is done to battery SOC estimation module below:
Battery SOC estimation module determines the cycle life and temperature range that off-line identification battery model parameter is applicable in, with
This determines off-line identification frequency, and charge and discharge are considered as two kinds of situations and are calculated separately；Zero during mixed pulses test simultaneously
When input time is shorter, capacitance initial voltage can not ignore, to guarantee the accuracy cell tester of parameter identification；Measured
Temperature directly acts on the observation noise value of Kalman filtering.
Parameter identification module takes identified off-line, on condition that thinking parameter in certain cycle life and certain temperature range
Constant, specific calculate is to take second-order circuit while bulky capacitor of connecting based on circuit diagram shown in Fig. 3；
Charge and discharge should be considered as two kinds of situations and calculated separately by parameter:
Circuit equation: Ut=Uoc+IR0+Up1+Up2； (1)
Open-circuit voltage: UocU after being stood with long-timetIt indicates；
Ohmic resistance: R0It is acquired by leaping voltage than electric current；
Bulky capacitor:
Calculate time constant:
Calculate polarization resistance:
Particularly, when calculating the polarization resistance under charged state, it can not ignore capacitance initial voltage,
That is:
Polarization capacity:
The above parameter is calculated by discretization Current Voltage；
The parameter acquired is inputted into battery SOC estimation module；
Battery SOC estimation module specific steps, i.e. Extended Kalman filter detailed process are as shown in Figure 4；
Wherein Extended Kalman filter quantity of state selects Up1、Up2, SOC, control amount select Ik；
The relationship of SOC and open-circuit voltage is obtained by open circuit voltage method, by least square fitting at function UOCV=f
(SOC)；
The state equation of discretization is made by current integration method:
Observational equation is obtained by circuit are as follows: UT, k+1=g (xk+1, Ik+1)=UOcv, k+1+UP1, k+1+UP2, k+1+R0Ik+1； (8)
Init state amount, state variance matrix, observation noise: SOC, Up1、Up2、P0,R；
State one-step prediction:
Xk+1=AkXk+BkUk, wherein
Observational equation: Yk=HkXk+Vk； (10)
One-step prediction variance matrix:
It linearizes observing matrix (H seeks local derviation about t):
Covariance prediction: P_pre=A*P0*A′；；(13)
Filtering gain matrix: Kg=P_pre*H '/(H*P_pre*H '+R)； (14)
State updates: Xk+1=Xk+Kg(UT, k-Yk)； (15)
Extended Kalman filter is by carrying out linear process to non-linear observing matrix, and by continuous iteration, when solution
Storage mass data is not required, the filter value that new data can be calculated newly is observed, so being very suitable for handling in real time.
Extended Kalman filter finally realizes the optimal estimation made in minimum variance meaning to the state of dynamical system, very suitable
It closes and states power battery SOC estimation.
The default function of logic control plate includes being judged when restarting after stopping for a long time using open circuit voltage method
SOC value is simultaneously output to LCD display, and the specific set time is according to the value C of bulky capacitor in battery equivalent circuit0It determines.
Main control module to the control of power battery charge-discharge electric power according to battery charge electricity condition be divided into rise an area, platform area and
Rise two area's three parts, obtains the relationship of SOC and open-circuit voltage with specific reference to open circuit voltage method, pass through least square fitting Cheng Han
Number UOCV=f (SOC) obtains subregion.
Main control module can make feedback control by connecting power battery, and detection display screen shows that SOC value presses set interval control
Charge-discharge electric power processed.
It should be understood that the part that this specification does not elaborate belongs to the prior art.
Although being described in conjunction with the accompanying specific embodiment of the present utility model above, those of ordinary skill in the art
It should be appreciated that these are merely examples, various deformation or modification can be made to these embodiments, it is practical without departing from this
Novel principle and essence.The scope of the utility model is only limited by the claims that follow.
Claims (5)
1. a kind of power battery of pure electric automobile state-of-charge estimating system, characterized in that including power battery, data acquisition module
Block, battery SOC estimation module, main control module and LCD display；Main control module is separately connected power battery, battery SOC estimation mould
Block and LCD display, power battery are sequentially connected data acquisition module, and data acquisition module is connect with battery SOC estimation module.
2. power battery of pure electric automobile state-of-charge estimating system as described in claim 1, characterized in that data acquisition module
Block includes that voltage collection circuit, large capacity high-precision hall current sensor, the electric thermo-couple temperature based on " winged capacitor " technology pass
Sensor is respectively used to end voltage, total current and the temperature data of acquisition power battery.
3. power battery of pure electric automobile state-of-charge estimating system as claimed in claim 2, characterized in that data acquisition module
Block includes the AQS225R2S4 that the voltage collection circuit based on " winged capacitor " technology selects Panasonic company.
4. power battery of pure electric automobile state-of-charge estimating system as described in claim 1, characterized in that main control module connects
It is connected to battery SOC estimation module, with the progress of control parameter identification and Kalman Filter Estimation；Main control module is connected to dynamic simultaneously
On power battery, for the charge and discharge output power of power battery being controlled according to the output valve of battery SOC estimation module to protect electricity
Charge and discharge are crossed in pond；Main control module is connected with LCD display by CAN bus, shows remaining capacity by LCD display.
5. power battery of pure electric automobile state-of-charge estimating system as described in claim 1, characterized in that power battery is
Lithium iron phosphate flexible package battery or ternary lithium battery.
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| CN201821692611.7U CN209198628U (en) | 2018-10-18 | 2018-10-18 | A kind of power battery of pure electric automobile state-of-charge estimating system |
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Granted publication date: 20190802 Termination date: 20201018 |