CN114368320B - Control method and system for actively managing whole vehicle SOC according to weather forecast - Google Patents

Abstract

The invention discloses a control method and a system for actively managing the whole vehicle SOC according to weather forecast. The invention adopts the correction algorithm to improve the electric quantity of the battery in the running process, ensures that the charge and discharge power of the battery reaches the target value after the next power-on process, can meet the basic acceleration requirements of an engine starting and a driver in the running process, and can reduce or even avoid starting a battery heating system on the premise of enough electric quantity so as to achieve the aim of reducing energy consumption.

Description

Control method and system for actively managing whole vehicle SOC according to weather forecast

Technical Field

The invention relates to the technical field of electric automobile control, in particular to a control method and a system for actively managing the whole automobile SOC according to weather forecast.

Background

For a hybrid vehicle, if the environmental temperature is too low, serious attenuation of the discharge power and the charge power of the battery in the low-temperature environment occurs after the vehicle is parked for one night, and particularly, the charge-discharge power may be limited to 0 under the working condition of low SOC, so that most vehicle types improve the battery capacity by heating the battery during the starting process, and meanwhile, the driving energy can be provided for the hybrid vehicle through an engine when the battery is severely attenuated.

The scheme of heating the battery requires time to heat, if the SOC is low, the battery cannot output larger power or even no power in a period of time due to larger limitation of charge and discharge power in the heating process, the result that the engine cannot be started can be caused for a vehicle type started by the P1 motor, and meanwhile the acceleration performance of the whole vehicle can be obviously influenced; the scheme of heating the battery consumes a part of energy at the same time, so that the endurance mileage is shortened.

Disclosure of Invention

The method can identify the weather in the last days in advance, the electric quantity of the battery in the driving process is improved by adopting a correction algorithm, the charge and discharge power of the battery reaches the target value after the next power-on process, the engine starting and basic acceleration requirements of a driver in the driving process can be met, and meanwhile, the battery heating system can be reduced or even not started on the premise of enough electric quantity, so that the purpose of reducing the energy consumption is achieved. The specific technical scheme is as follows.

As a first aspect, the present invention provides a control method for actively managing the SOC of a whole vehicle according to weather forecast, where the steps include:

s1, collecting weather information of the current day and the previous N days, and judging whether to execute an active management SOC program according to the weather information;

s2, if the vehicle is judged to be executed, starting to calculate a target SOC meeting the required state of the vehicle;

s3, selecting and correcting the target SOC by identifying the parameters of the current whole vehicle to obtain the corrected target SOC of the current vehicle needing electricity protection;

s4, keeping the actual SOC of the whole vehicle within the range of the corrected target SOC according to the energy management strategy.

With reference to the first aspect, in a first case of any one of the possible cases, the step S1 includes:

s11, obtaining weather temperatures for N days, namely T1, T2, T3, TN, calculating and processing to obtain the latest N balance average temperature Tp= (T1+T2+ & TN)/N, and simultaneously calculating the variance Sp= [ (T1-Tp)/(2-Tp)/(2+ (T3-Tp)/(2+ & TN-Tp)/(2 ]/N) of the latest N days;

s12, judging the condition that the active management SOC needs to be started as follows:

the average temperature Tp is less than or equal to a preset temperature value Ta;

the temperature variance Sp is more than or equal to a preset temperature difference Tb & the temperature of any day in the last N days is less than or equal to a preset temperature value c;

ta is a temperature value at which the discharge capacity of the battery is reduced by half;

tb is a temperature difference value of rapid cooling in the last N days;

tc, the temperature value of the lowest temperature in the last N days is calculated by variance;

if so, the active management SOC condition is satisfied.

In combination with the first case, the second case in any one of the cases that may occur is that the step S2 includes:

s21, obtaining the required power P of an engine;

s22, determining the charge and discharge power Pm of the corresponding battery of the BMS at different temperatures and different SOCs according to the performance parameters of different batteries;

s23, inputting a preset model according to Pm, input P/n and average temperature Tp to calculate to obtain a target SOC, wherein n represents the conversion efficiency from a battery end to a motor end.

In combination with the second case, a third case in any one of the cases that may occur is that the step S3 includes:

s31, obtaining a corrected proportionality coefficient lambda 1 of the environmental temperature difference, wherein the calculation logic is as follows:

λ1= |current ambient temperature T0-current ambient temperature T1| of the current ambient temperature T1-recent N balance average temperature tp|t0/tp|;

s32, obtaining a preset proportional coefficient lambda 2 corresponding to different operation modes and a preset gain coefficient delta 1 which is finely adjusted according to different environment temperatures;

s33, judging whether to carry out target SOC correction according to preset judging conditions, and if so, carrying out correction according to the following logic: corrected target soc=target SOC λ1 λ2+Δ1.

In combination with the third case, in a fourth case of any one of the possible situations, the target SOC is divided into a target SOC1 meeting the engine start and a target SOC2 meeting the power demand, and the corresponding required power P of the engine is divided into a maximum value P1 of the required power for engine start and a power P2 required by a battery meeting the basic acceleration demand of the whole vehicle according to different temperatures of the environmental cabin;

obtaining a target SOC1 according to Pm, the input P1/n and the average temperature Tp;

the target SOC2 is obtained from Pm, the input P2/n and the average temperature Tp.

In combination with the fourth case, in a fifth case in any one of the cases that may occur, it is determined whether or not to perform the target SOC correction according to a preset determination condition as: correcting the target SOC when the oil quantity or the vehicle speed is lower than a preset value, and adjusting the target SOC to be the target SOC1; and when the oil quantity or the vehicle speed exceeds a preset value, correcting the target SOC, and adjusting the target SOC to be the target SOC2.

In combination with the first aspect and any one of the first to fifth cases, a sixth case in which any one of the first to fifth cases may occur is that the energy management policy in the method is:

when the actual SOC is more than or equal to the corrected target SOC and the preset error upper limit SOC, the engine is started after the whole vehicle required power exceeds the battery capacity, otherwise, the engine is not started;

when the correction target SOC and the preset error upper limit SOC are larger than or equal to the actual SOC and larger than or equal to the correction target SOC and the preset error SOC, starting the engine to enter a series power generation mode, and generating power according to the requirement by the engine to ensure that the whole vehicle SOC is always kept in the range of the correction target SOC;

when the actual SOC is less than or equal to the corrected target SOC and is equal to the preset error SOC, the engine is started for a long time, and the SOC can be ensured to be within the range of the corrected target SOC.

As a second aspect, the present invention discloses a control system for actively managing the SOC of an entire vehicle according to weather forecast, the system including a PAD system and a VCU system, wherein:

the VCU system is used for managing and controlling the whole vehicle SOC according to the temperature information of N days;

the PAD system is used for acquiring temperature information of N days for analysis and use of the VCU system, receiving information fed back by the VCU system and providing a man-machine interaction function.

As a third aspect, the present invention provides a computer readable storage medium storing one or more programs, characterized in that the computer readable storage medium stores one or more program instructions which, when executed by a processor, perform any one of the methods described above.

As a fourth aspect, the present invention provides an electric vehicle characterized in that the vehicle is mounted with the above-described system and the above-described computer-readable storage medium storing program instructions for the system to operate.

The beneficial effects of the invention are as follows:

the invention can effectively estimate the SOC to be kept when the vehicle is used next time by using the information of the weather forecast, is suitable for the northern cold weather, and can reduce the risk that the engine of the hybrid electric vehicle cannot be started after being placed outdoors for one night and the acceleration in the driving process is weak. Meanwhile, on the premise of not increasing the cost of the whole vehicle, the energy-saving effect is realized through specific control logic.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the invention, and that other drawings can be obtained from these drawings without inventive faculty for a person skilled in the art.

FIG. 1 is a system flow diagram of the present invention;

FIG. 2 is a table of rolling resistance coefficient versus power parameter during operation of a vehicle model;

FIG. 3 is a table of constant speed required power parameters during operation of a vehicle model;

FIG. 4 is a table of discharge parameters for a model of a vehicle with a ternary lithium battery;

FIG. 5 is a table of power parameters for engine start requirements for a vehicle model;

FIG. 6 is a graph of target SOC ranges for meeting start-up and endurance conditions;

FIG. 7 is a graph of target SOC ranges for acceleration conditions;

FIG. 8 is a target SOC calculation logic

FIG. 9 is a conditional determination of target SOC correction;

FIG. 10 is a table of simulated target SOC versus temperature;

FIG. 11 is a target SOC correction calculation result;

fig. 12 is a system configuration diagram of the present invention.

Detailed Description

The technical scheme of the invention is further specifically described below through examples and with reference to the accompanying drawings. It is apparent that the described embodiments are only some of the embodiments of the present invention.

Example 1

As shown in fig. 1, the embodiment discloses a control method for actively managing the SOC of a whole vehicle according to weather forecast, and the general method flow is as follows:

step S1: after the whole vehicle is electrified, PAD (multimedia) collects the information of the latest 7-day weather forecast, and feeds the information back to VCU to perform function starting logic judgment;

the VCU calculates the weather temperature of the last 7 days to be T1 (the day), T2, T3, T4, T5, T6 and T7 respectively to obtain the latest 7 balance average temperature Tp= (T1+T2+T3+T4+T5+T6+T7)/7;

the variance of the temperature (temperature stability) was calculated for the last 7 days at the same time: sp= [ (T1-Tp)/(2+ (T2-Tp)/(3-Tp)/(2+ (T4-Tp)/(2+ (T5-Tp)/(2+ (T6-Tp)/(2+ (T7-Tp)) ]/7).

The conditions under which the VCU determines that the active management SOC needs to be turned on are as follows:

calculating the average temperature Tp less than or equal to Ta (the temperature value affecting the discharge capacity of the battery);

the temperature variance Sp is more than or equal to Tb (the temperature difference is more than a certain range) & any day of the last 7 days is less than or equal to Tc (the temperature value affecting the discharge capacity of the battery);

ta is a temperature value for reducing the discharge capacity of the battery by half, wherein the temperature of the ternary lithium battery is about 0 ℃, and the temperature of the ferric phosphate lithium battery is about 5 ℃;

tb is a temperature difference range for judging whether rapid cooling occurs in the last 7 days, and the dispersion of the temperature of Tb=10 is generally considered to be strong;

tc-tc=5 ℃ was calculated based on variance, with the lowest air temperature present in the last 7 days resulting in a decrease in battery discharge capacity.

As shown in fig. 2, after the active management SOC condition is met, the VCU recognizes that the current driving condition is READY, the whole gear is P gear, and a spring frame is sent to the PAD on the premise that the driving safety is guaranteed without the current vehicle speed, so as to prompt the user whether to select the active management SOC.

The PAD feeds back the selection result of the driver, and is not allowed by default if the driver does not select for a long time.

Step S2: after the driver selects the VCU to actively manage the SOC, the VCU starts to calculate the SOC value meeting the next power-on starting and accelerating;

calculating the required power P1 for starting the engine, wherein the required power P1 for starting the engine takes the maximum value according to different temperatures of the environmental cabin; the power P2 required to be provided by the battery meeting the basic acceleration requirement of the whole vehicle is calculated, the P2 is calculated according to the difference between the calculated power of acceleration and the power limited according to NVH after the engine is started, and specific parameters can be referred to fig. 2 and 3.

The BMS determines the charge and discharge power Pm of the corresponding battery at different temperatures and different SOCs according to the performance parameters of the different batteries, and the data in fig. 4 can be referred to specifically.

According to Pm, comparing the result of table lookup with FIG. 4, and the values of P1/n and P2/n, adding the average temperature Tp calculated in the step 1 to a preset model, and calculating to obtain a battery target SOC1 meeting the engine starting and a battery target SOC2 meeting the power requirement; where n represents the battery end to motor end conversion efficiency.

The specific calculation logic is shown in fig. 6, and the calculation logic of a target SOC2 meeting a certain vehicle type starting target SOC1 (shown in fig. 5) and a constant-speed 100km/h (the required power is 17.2 kw) of a circulation working condition is analyzed through simulation data, and the target SOC needs to be corrected according to the environment temperature when the environment temperature is lower than 0 ℃.

If the acceleration performance of 0-100 km under the low-temperature working condition needs to be met, the power P2 requirement calculated by a certain vehicle model is shown in the following table:

the acceleration performance requirement of a driver of a certain vehicle type is met, the acceleration performance of the SOC2 at 15% and the temperature of 9 ℃ can be met by 0-100 km according to the simulation result, and the simulation result (as shown in figure 7) shows that the values of the SOC2 corresponding to different temperatures are different.

Step S3: the VCU selects and corrects the target SOC calculated in the step S2 by identifying various parameters of the current whole vehicle to obtain the SOC value of the current vehicle which needs to be kept electricity, and simultaneously identifies the working conditions which are the enabling states which do not need to adopt the calculated value to obtain the effectiveness;

the conditions currently required to be considered for correction are as shown in fig. 8 below, the target SOC is corrected according to the environmental temperature difference, and the corrected scaling factor λ1 has the following calculation logic:

λ1= |current ambient temperature T0-current ambient temperature T1| of current ambient temperature T1-latest 7 balance average temperature tp|t 0/tp|; wherein the limiting range of the value of lambda 1 is [0.8,1.2]

The target SOC is corrected according to the proportionality coefficients of different operation modes (ECO/NORMAL/SPORT), and the proportionality coefficient corresponding relation is lambda 2, and the table is searched according to the different operation modes to obtain;

correcting the target SOC according to the current environment temperature, wherein the corresponding relation of the gain coefficient delta 1 is obtained by carrying out fine adjustment according to different environment temperatures and carrying out coefficient table lookup;

as shown in fig. 8, it is also necessary to determine whether to perform correction based on the conditions of the oil amount and the vehicle speed, and whether to perform correction based on the determination logic shown in fig. 9. Adjusting the target SOC to be SOC1 meeting the starting requirement for preventing the frequent starting and stopping of the engine under the condition of low oil quantity or low vehicle speed, and adjusting the target SOC to be SOC2 meeting the power requirement when the oil quantity or the vehicle speed exceeds the target value;

the user may select a different operation mode (EV (pure electric), HEV (hybrid), FHEV (fuel)) and the logic of the corresponding target SOC correction calculation at this time may be differentiated, and the EV and FHEV modes may not respond to the target calculation value and may only respond in the HEV mode.

Corrected value of target soc=target soc×λ1×λ2+Δ1.

The relation between the simulated target SOC and the temperature meets the requirement of the dynamic property P2, the relation between the simulated target SOC and the simulated temperature is shown in fig. 10, and after the target SOC is calculated, the SOC is corrected according to different operation habits of a driver and the actual state of the whole vehicle. The corrected target SOC is shown in fig. 11, in which λ1=0.95, λ2=0.95, and Δ1=5% are set.

Step 4: obtaining corrected target SOC conditions and enabling signals through the step 3, and then keeping the SOC of the whole vehicle within a target SOC value range through an energy management strategy of the VCU, wherein the energy management strategy is adopted in the following way:

when the actual SOC is more than or equal to the corrected target SOC and the preset error upper limit SOC, the engine is started after the whole vehicle required power exceeds the battery capacity, otherwise, the engine is not started;

when the correction target SOC and the preset error upper limit SOC are larger than or equal to the actual SOC and larger than or equal to the correction target SOC and the preset error SOC, starting the engine to enter a series power generation mode, and generating power according to the requirement by the engine to ensure that the whole vehicle SOC is always kept in the range of the correction target SOC;

when the actual SOC is less than or equal to the corrected target SOC and is equal to the preset error SOC, the engine is started for a long time, and the SOC can be ensured to be within the range of the corrected target SOC.

By the method, the SOC to be kept when the vehicle is used next time can be estimated by effectively utilizing the information of the weather forecast, the method is suitable for the northern cold weather, and the risk that the engine cannot be started after the hybrid electric vehicle is placed outdoors for one night and the acceleration in the driving process is weak can be reduced. Meanwhile, on the premise of not increasing the cost of the whole vehicle, the energy-saving effect is realized through specific control logic.

Example 2

As shown in fig. 12, the present embodiment provides a system that implements the technical effects of the present invention by applying the above-described method.

The embodiment provides a control system for actively managing the whole vehicle SOC according to weather forecast, wherein the system comprises a PAD system and a VCU system, and the control system comprises the following components:

the VCU system is used for managing and controlling the whole vehicle SOC according to the temperature information of N days;

the PAD system is used for acquiring temperature information of N days for analysis and use of the VCU system, receiving information fed back by the VCU system and providing a man-machine interaction function.

It should be understood that the above-described embodiments are merely illustrative of the present invention and are not intended to limit the scope of the present invention. It is also to be understood that various changes and modifications may be made by those skilled in the art after reading the disclosure herein, and that such equivalents are intended to fall within the scope of the claims appended hereto.

Claims (4)

1. The control method for actively managing the whole vehicle SOC according to the weather forecast is characterized by comprising the following steps:

s1, collecting weather information of the current day and the previous N days, and judging whether to execute an active management SOC program according to the weather information;

s2, if the vehicle is judged to be executed, starting to calculate a target SOC meeting the required state of the vehicle;

s3, selecting and correcting the target SOC by identifying the parameters of the current whole vehicle to obtain the corrected target SOC of the current vehicle needing electricity protection;

s4, keeping the actual SOC of the whole vehicle within the range of the corrected target SOC according to an energy management strategy;

the step S1 includes:

s11, obtaining weather temperatures for N days, namely T1, T2, T3, TN, calculating and processing to obtain the latest N balance average temperature Tp= (T1+T2+ & TN)/N, and simultaneously calculating the variance Sp= [ (T1-Tp)/(2-Tp)/(2+ (T3-Tp)/(2+ & TN-Tp)/(2 ]/N) of the latest N days;

s12, judging the condition that the active management SOC needs to be started as follows:

the average temperature Tp is less than or equal to a preset temperature value Ta;

the temperature variance Sp is larger than or equal to a preset temperature difference Tb, and the temperature of any day in the last N days is smaller than or equal to a preset temperature value c;

ta is a temperature value at which the discharge capacity of the battery is reduced by half;

tb is a temperature difference value of rapid cooling in the last N days;

tc, the temperature value of the lowest temperature in the last N days is calculated by variance;

if yes, the active management SOC condition is satisfied;

the step S2 includes:

s21, obtaining the required power P of an engine;

s22, determining the charge and discharge power Pm of the corresponding battery of the BMS at different temperatures and different SOCs according to the performance parameters of different batteries;

s23, inputting a preset model according to Pm, input P/n and average temperature Tp to calculate to obtain a target SOC, wherein n represents the conversion efficiency from a battery end to a motor end;

the step S3 includes:

s31, obtaining a corrected proportionality coefficient lambda 1 of the environmental temperature difference, wherein the calculation logic is as follows:

λ1=current ambient temperature T0-current ambient temperature T1-current N balance average temperature tp×t0/Tp;

s32, obtaining a preset proportional coefficient lambda 2 corresponding to different operation modes and a preset gain coefficient delta 1 which is finely adjusted according to different environment temperatures;

s33, judging whether to carry out target SOC correction according to preset judging conditions, and if so, carrying out correction according to the following logic: corrected target soc=target SOC λ1 λ2+Δ1;

the target SOC is divided into a target SOC1 meeting the engine starting and a target SOC2 meeting the power performance requirement, and the corresponding required power P of the engine is divided into a maximum value P1 of the engine starting required power at different temperatures of the environmental cabin and a power P2 required by a battery meeting the basic acceleration requirement of the whole vehicle;

inquiring a preset parameter comparison table according to Pm, the input P1/n and the average temperature Tp to obtain a target SOC1;

and inquiring a preset parameter comparison table according to Pm, the input P2/n and the average temperature Tp to obtain the target SOC2.

2. The control method for actively managing the SOC of a whole vehicle according to a weather forecast of claim 1, wherein determining whether to perform the target SOC correction according to a preset determination condition is: correcting the target SOC when the oil quantity or the vehicle speed is lower than a preset value, and adjusting the target SOC to be the target SOC1; and when the oil quantity or the vehicle speed exceeds a preset value, correcting the target SOC, and adjusting the target SOC to be the target SOC2.

3. The control method for actively managing a complete vehicle SOC according to a weather forecast according to any of claims 1 to 2, wherein the energy management strategy is:

when the actual SOC is more than or equal to the corrected target SOC and the preset error upper limit SOC, the engine is started after the whole vehicle required power exceeds the battery capacity, otherwise, the engine is not started;

when the correction target SOC and the preset error upper limit SOC are larger than or equal to the actual SOC and larger than or equal to the correction target SOC and the preset error SOC, starting the engine to enter a series power generation mode, and generating power according to the requirement by the engine to ensure that the whole vehicle SOC is always kept in the range of the correction target SOC;

when the actual SOC is less than or equal to the corrected target SOC and is equal to the preset error SOC, the engine is started for a long time, and the SOC can be ensured to be within the range of the corrected target SOC.

4. A computer readable storage medium storing one or more programs, wherein the computer readable storage medium stores one or more program instructions which, when executed by a processor, perform a method as claimed in any one of claims 1 to 3.