A method and device for controlling power balance based on WLTC working condition

Abstract

The present invention discloses a method and device for controlling battery balancing under a WLTC operating condition. The method involves obtaining temperature and altitude information when a vehicle enters a powered-on state. Based on the temperature and altitude information, the method determines a pre-calibrated primary correction interval, a balancing interval, and ΔSOC, and performs a first correction on a preset initial target SOC to obtain a primary corrected target SOC. When the primary corrected target SOC is within the primary correction interval and a vehicle power enable signal is detected, the method obtains the actual SOC sent by the battery controller. When the actual SOC is within the balancing interval, the method determines a secondary corrected target SOC based on the actual SOC and ΔSOC, which serves as a reference for controlling battery charging and discharging by the vehicle engine. The method also calculates the battery SOC change based on the voltage and current feedback from the battery controller. Finally, the method determines the output SOC sent by the vehicle controller based on the actual SOC and the battery SOC change. This reduces the initial battery charge requirement for battery balancing under WLTC operating conditions, enabling rapid balancing when performing a WLTC CS battery hold test when the battery charge is within a certain range, thus reducing the number of rotating drum tests.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, and in particular to a method and device for controlling power balance based on a WLTC operating condition. Background Art

[0002] Under the WLTC operating condition test, hybrid vehicles are required to have a battery energy change of less than 4% of the total energy of the entire driving cycle before and after the CS charge retention test.

[0003] The current WLTC battery balance control methods mostly perform closed-loop control of battery balance based on the difference between the BMS_SOC fed back by the high-voltage battery controller BMS and the set target SOC. However, the BMS_SOC fed back by the BMS is estimated by the integral of the high-voltage battery current based on time and cannot feedback the actual energy of the high-voltage system.

[0004] Since the BMS_SOC fed back by the BMS cannot truly reflect the actual energy status of the battery, the battery is prone to SOC jumps or corrections during the test after frequent charge and discharge in the cycle; at the same time, the BMS_SOC may also be corrected according to temperature changes and voltage changes after the vehicle is immersed. The BMS_SOC when the test is restarted after the vehicle is immersed is an uncertain value. If the target SOC of the closed-loop control in the cycle is fixed, the actual SOC before and after the test may deviate significantly, resulting in test failure. Summary of the Invention

[0005] In view of the above problems, the present invention is proposed to provide a power balance control method and device based on the WLTC operating condition, which reduces the requirements of the power balance under the WLTC operating condition on the initial battery power of the test, so that when the battery power is within a certain range and the CS power maintenance test of the WLTC operating condition is carried out again, the balance can be achieved quickly, thereby reducing the number of rotating hub tests.

[0006] According to a first aspect of the present invention, a method for controlling power balance based on a WLTC operating condition is provided, comprising:

[0007] When the vehicle enters the power-on state, obtain temperature information and altitude information;

[0008] Determining a pre-calibrated primary correction interval, equilibrium interval, and ΔSOC based on the temperature information and the altitude information, and performing a first correction on the preset initial target SOC to obtain a primary corrected target SOC; the ΔSOC is the difference between the fixed target SOC and the equilibrium point SOC tested and calibrated at different temperatures and altitudes;

[0009] When the primary corrected target SOC is within the primary corrected range and a vehicle power enable signal is detected, obtaining an actual SOC sent by a battery controller;

[0010] When the actual SOC is in the balance range, determining a secondary corrected target SOC based on the actual SOC and the ΔSOC, and using the secondary corrected target SOC as a reference value for controlling charging and discharging of the battery by the vehicle engine;

[0011] Calculate the battery SOC change based on the voltage and current feedback from the battery controller;

[0012] The output SOC sent by the vehicle controller is determined according to the actual SOC and the battery SOC change.

[0013] Optionally, performing a first correction on the preset initial target SOC to obtain a corrected target SOC includes:

[0014] performing temperature correction on the initial target SOC according to the temperature information to obtain a temperature-corrected initial target SOC;

[0015] The temperature-corrected initial target SOC is subjected to altitude correction according to the altitude information to obtain the first-corrected target SOC.

[0016] Optionally, the temperature information includes battery temperature and ambient temperature;

[0017] The step of performing temperature correction on the initial target SOC according to the temperature information to obtain the temperature-corrected initial target SOC includes:

[0018] When the ambient temperature is less than a preset threshold, selecting a minimum temperature from the battery temperature and the ambient temperature as a reference temperature, and performing temperature correction on the initial target SOC according to the reference temperature to obtain a temperature-corrected initial target SOC;

[0019] When the ambient temperature is greater than or equal to a preset threshold, a maximum temperature is selected from the battery temperature and the ambient temperature as a reference temperature, and the initial target SOC is temperature-corrected according to the reference temperature to obtain a temperature-corrected initial target SOC.

[0020] Optionally, performing temperature correction on the initial target SOC according to the reference temperature to obtain the temperature-corrected initial target SOC includes:

[0021] According to the reference temperature, a match is performed in a preset temperature and SOC adjustment amount comparison table. If the match is successful, the initial target SOC is temperature-corrected according to the SOC adjustment amount corresponding to the successfully matched temperature to obtain the temperature-corrected initial target SOC, wherein the temperature and SOC adjustment amount comparison table includes temperatures and SOC adjustment amounts corresponding to the temperatures.

[0022] Optionally, determining a secondary corrected target SOC according to the actual SOC and the ΔSOC includes:

[0023] The difference between the actual SOC and the ΔSOC is the secondary corrected target SOC.

[0024] Optionally, the method further includes:

[0025] If the vehicle power enable signal is not detected, the output SOC sent by the vehicle controller is updated according to the actual SOC sent by the battery controller.

[0026] Optionally, the battery SOC change calculated based on the voltage and current fed back by the battery controller includes:

[0027] Calculating the product of the voltage and current fed back by the battery controller, integrating the product with respect to time, and obtaining a total energy change of the battery;

[0028] The battery SOC change is calculated based on the battery total energy and the battery total energy change.

[0029] According to a second aspect of the present invention, there is provided a power balancing control device based on a WLTC operating condition, comprising:

[0030] An acquisition unit, used to acquire temperature information and altitude information when the vehicle enters a power-on state;

[0031] a first correction unit, configured to determine a pre-calibrated first correction interval, a balance interval, and a ΔSOC based on the temperature information and the altitude information, and to perform a first correction on the preset initial target SOC to obtain a first-corrected target SOC; the ΔSOC being the difference between the fixed target SOC and the balance point SOC, as determined by tests at different temperatures and altitudes;

[0032] a detection unit, configured to obtain an actual SOC sent by a battery controller when the primary-corrected target SOC is within the primary-corrected interval and a vehicle power enable signal is detected;

[0033] a second correction unit, configured to determine a second-corrected target SOC based on the actual SOC and the ΔSOC when the actual SOC is in the equilibrium range, and use the second-corrected target SOC as a reference value for controlling charging and discharging of the battery by the vehicle engine;

[0034] The output unit is used to calculate the battery SOC change based on the voltage and current feedback from the battery controller; and determine the output SOC sent by the vehicle controller based on the actual SOC and the battery SOC change.

[0035] According to a third aspect of the present invention, a computer-readable storage medium is provided, on which a computer program is stored. When the program is executed by a processor, the above-mentioned power balancing control method based on the WLTC operating condition is implemented.

[0036] According to a fourth aspect of the present invention, a plug-in hybrid vehicle is provided, comprising a vehicle body and a controller installed in the vehicle body, wherein the controller executes the aforementioned charge balance control method based on the WLTC operating condition.

[0037] The above one or more technical solutions in the embodiments of this specification have at least the following technical effects:

[0038] The embodiments of this specification provide a method and device for controlling battery balancing under WLTC conditions. The method involves obtaining temperature and altitude information when a vehicle enters a powered-on state. Based on the temperature and altitude information, the method determines a pre-calibrated primary correction interval, a balancing interval, and a ΔSOC, and performs a first correction on a preset initial target SOC to obtain a primary corrected target SOC. When the primary corrected target SOC is within the primary correction interval and a vehicle power enable signal is detected, the method obtains the actual SOC sent by the battery controller. When the actual SOC is within the balancing interval, the method determines a secondary corrected target SOC based on the actual SOC and ΔSOC, which serves as a reference for controlling battery charging and discharging by the vehicle engine. The method also calculates the battery SOC change based on the voltage and current feedback from the battery controller. Finally, the method determines the output SOC sent by the vehicle controller based on the actual SOC and the battery SOC change. This reduces the initial battery charge requirement for battery balancing under WLTC conditions, enabling rapid balancing when performing a WLTC CS charge retention test when the battery charge is within a certain range, thus reducing the number of rotating drum tests.

[0039] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. Throughout the drawings, the same reference figures denote the same components. In the drawings:

[0041] Figure 1 A flow chart of a power balancing control method based on the WLTC operating condition in an embodiment of the present invention is shown.

[0042] Figure 2 A block diagram of a power balancing control device based on a WLTC operating condition in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0045] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0046] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0047] The embodiment of the present invention provides a power balance control method based on WLTC working condition, combined with Figure 1 As shown in the flowchart, the method includes steps 101 to 106:

[0048] Step 101: When the vehicle enters the power-on state, obtain temperature information and altitude information;

[0049] In this embodiment, the vehicle is a plug-in hybrid vehicle. The WLTC operating condition refers to the Worldwide Harmonized Light Vehicle Test Cycle. The power-on state refers to the high voltage on the vehicle. When it is detected that the vehicle enters the power-on state, temperature information and altitude information are obtained. Among them, the temperature information and altitude information represent the current environmental conditions of the vehicle. Different temperature information and altitude information may correspond to different environmental conditions. Common environmental conditions in this embodiment include normal temperature and normal pressure environment, normal temperature and high altitude environment, etc. For example, an altitude greater than 1000 meters is set as high altitude, and an altitude less than 1000 meters is set as low altitude, that is, normal pressure environment.

[0050] Step 102: Determine a pre-calibrated primary correction interval, equilibrium interval, and ΔSOC based on the temperature information and the altitude information, and perform a first correction on the preset initial target SOC to obtain a primary corrected target SOC; ΔSOC is the difference between the fixed target SOC and the equilibrium point SOC, as determined by testing at different temperatures and altitudes.

[0051] In this embodiment, after determining the temperature information and altitude information, the environmental conditions of the vehicle can be determined. Different environmental conditions have slightly different corresponding calibration intervals, equilibrium intervals and ΔSOC. ΔSOC can be determined based on the temperature information and altitude information, or based on the one-time correction interval. ΔSOC refers to the fuel consumption optimization test determined by multiple WLTC operating condition tests under the same environmental conditions with a fixed target SOC (equivalent to the initial target SOC remaining unchanged), and is calculated from the difference between the fixed target SOC and the equilibrium point SOC. In this embodiment, if it is a normal temperature and normal pressure environment, ΔSOC can be calibrated to 0.5%; if it is a normal temperature and high altitude environment, ΔSOC can be calibrated to 0.3%.

[0052] The initial target SOC refers to the SOC value preset in the hybrid vehicle, which is used to control the engine operation to maintain the charge in the battery near the initial target SOC.

[0053] It should be noted that since battery operation is affected by temperature and altitude, vehicles with the same initial target SOC may not experience any impact on normal vehicle operation at normal temperature and pressure. However, at normal temperature and high altitude, this may affect normal vehicle operation. Furthermore, a fixed initial target SOC is not conducive to the CS charge retention cycle test under the WLTC operating condition.

[0054] Therefore, this embodiment will make a first correction to the preset initial target SOC based on the temperature information and altitude information, specifically including:

[0055] performing temperature correction on the initial target SOC according to the temperature information to obtain a temperature-corrected initial target SOC;

[0056] The temperature-corrected initial target SOC is subjected to altitude correction according to the altitude information to obtain the first-corrected target SOC.

[0057] In this embodiment, the first correction primarily involves two aspects: temperature correction of the initial target SOC and altitude correction of the initial target SOC. These two corrections are additive. In this embodiment, the initial target SOC is first temperature-corrected to obtain a temperature-corrected SOC value, namely, the temperature-corrected initial target SOC. Altitude correction is then performed based on the temperature correction. This means that the initial target SOC after temperature correction is corrected for altitude based on the altitude information, resulting in a corrected target SOC.

[0058] It should be noted that in this embodiment, the initial target SOC may be corrected for altitude first, and then temperature corrected based on the altitude correction. In other words, this embodiment does not limit the order of temperature correction and altitude correction.

[0059] It's important to note that temperature information includes at least two types: battery temperature and ambient temperature. The optimal operating temperature for a battery lies within a certain range, for example, 20-30°C or 15-35°C, depending on the specific battery. Temperatures below or above this range will affect the battery. Furthermore, battery temperature is not always constant, as the battery generates heat during charging and discharging.

[0060] Therefore, when performing temperature correction on the initial target SOC, it is necessary to analyze the battery temperature and ambient temperature, including:

[0061] When the ambient temperature is less than a preset threshold, selecting a minimum temperature from the battery temperature and the ambient temperature as a reference temperature, and performing temperature correction on the initial target SOC according to the reference temperature to obtain a temperature-corrected initial target SOC;

[0062] When the ambient temperature is greater than or equal to a preset threshold, a maximum temperature is selected from the battery temperature and the ambient temperature as a reference temperature, and the initial target SOC is temperature-corrected according to the reference temperature to obtain a temperature-corrected initial target SOC.

[0063] The preset threshold is pre-set. When the ambient temperature is less than the preset threshold, the smaller of the battery temperature and the ambient temperature is selected for temperature correction of the initial target SOC. Conversely, when the ambient temperature is greater than or equal to the preset threshold, the larger of the battery temperature and the ambient temperature is selected for temperature correction of the initial target SOC.

[0064] After determining the reference temperature between the battery temperature and the ambient temperature, a match can be performed in a preset temperature and SOC adjustment comparison table based on the reference temperature. If the match is successful, the initial target SOC is temperature-corrected based on the SOC adjustment amount corresponding to the successfully matched temperature to obtain the temperature-corrected initial target SOC.

[0065] The temperature-SOC adjustment comparison table includes temperatures and corresponding SOC adjustments. The temperature-SOC adjustment comparison table is searched based on the reference temperature. A temperature matching the reference temperature is matched. The SOC adjustment corresponding to that temperature is then used to perform temperature correction on the initial target SOC, resulting in a temperature-corrected initial target SOC.

[0066] Step 103: When the primary corrected target SOC is within the primary corrected range and a vehicle power enable signal is detected, obtaining an actual SOC sent by a battery controller;

[0067] In this embodiment, the value of the first-corrected target SOC may not be an integer, and a first-correction interval is needed to cover the accuracy of the first-corrected target SOC. If the first-corrected target SOC is within the first-correction interval and the vehicle power enable signal is detected, the second-correction is activated.

[0068] The vehicle power enable signal is a signal indicating that the vehicle can be driven in a driving gear. If the power enable signal is detected, it means that the vehicle can be driven in a gear. If the power enable signal is not detected, it means that the vehicle cannot be driven in a driving gear.

[0069] When the primary correction target SOC is in the primary correction range and the vehicle power enable signal is detected, the actual SOC sent by the battery controller BMS can be obtained.

[0070] Step 104: When the actual SOC is in the equilibrium range, determine a secondary corrected target SOC based on the actual SOC and the ΔSOC, and use the secondary corrected target SOC as a reference value for controlling the charging and discharging of the battery by the vehicle engine;

[0071] In this embodiment, the balance interval refers to the range of the actual SOC based on the current environmental conditions. If the actual SOC is within the balance interval, the vehicle can better control the charge balance during the CS charge maintenance cycle. The balance interval is closer to the primary corrected target SOC. For example, if the primary corrected target SOC is 15%, the balance interval can be (15.5%-17.5%).

[0072] When the actual SOC is within the equilibrium range, a secondary correction is triggered, allowing the vehicle to perform a CS energy conservation cycle test to better control the charge balance. The secondary correction target SOC is then determined based on the actual SOC and ΔSOC. This secondary correction target SOC serves as the baseline for controlling the vehicle engine's charging and discharging of the battery.

[0073] It's easy to see that the baseline value for the vehicle engine's battery charge and discharge in this embodiment is dynamically adjusted, not a preset fixed value. The vehicle in this embodiment is a plug-in hybrid vehicle using the ECMS equivalent fuel consumption minimization control strategy. This reduces the initial battery charge requirement for battery balance under WLTC conditions. This allows for rapid balance during the WLTC CS charge retention cycle test, ensuring the battery charge remains within a certain range. This reduces the number of rotating drum tests.

[0074] In addition, the equivalent factor used in the ECMS equivalent fuel consumption minimization strategy in this embodiment uses fewer parameters, and the hub calibration and simulation optimization are simple; there is also a decision-making layer for switching the vehicle's working mode (pure electric mode, series mode, parallel mode), which corrects the initial equivalent fuel consumption according to the current working mode and vehicle speed to reduce the frequency of mode switching or gear switching.

[0075] Step 105: Calculate the battery SOC change based on the voltage and current fed back by the battery controller;

[0076] In this embodiment, when the vehicle is running or tested, the total energy change of the battery during the battery charging and discharging process is calculated based on the product of the voltage and current fed back by the battery controller, and then integrated over time. This calculation method is more accurate. Because, during this process, the BMS_SOC value fed back by the battery controller BMS cannot truly reflect the actual energy state of the battery. After the battery is frequently charged and discharged in the cycle, it is easy for the SOC to jump or be corrected during the test. At the same time, the BMS_SOC may also be corrected according to temperature changes and voltage changes after the vehicle is immersed. The BMS_SOC when the test is started again after the vehicle is immersed is an uncertain value. If the initial target SOC of the closed-loop control in the cycle is fixed (without correction), the battery power before and after the test is likely to have a large deviation. If the BMS_SOC and the fixed target SOC are used to directly control the power balance, it is easy to cause the test results to not meet the requirements.

[0077] Furthermore, since the SOC displayed on the vehicle instrument panel is typically only accurate to 1%, and the battery capacity of plug-in hybrid vehicles is increasing, the SOC difference corresponding to the energy change in the CS charge retention mode cycle is becoming smaller and smaller. Therefore, the SOC control accuracy requirements in the test are becoming increasingly higher. Hybrid vehicles with large-capacity batteries generally need to control the SOC accuracy within 1%, but the SOC accuracy of the instrument display is basically indistinguishable. For example, an SOC of 14.5% and 15.5% may both be displayed as 15% on the instrument panel. If the closed-loop control method of charge balance is based on a fixed target SOC, the personnel cannot accurately start the test at a fixed SOC. For hybrid vehicles using the equivalent fuel consumption minimum strategy, this can easily cause inconsistencies between the engine start-stop and charge balance conditions in the WLTC operating condition, resulting in test failure.

[0078] Therefore, this embodiment uses the product of the voltage and current fed back by the battery controller, and then integrates the time to calculate the change in the total energy of the battery. After the change in the total energy of the battery is calculated, the change in the total energy of the battery is divided by the total energy of the battery to obtain the change in the battery SOC.

[0079] The difference between the actual SOC and ΔSOC is used as the secondary corrected target SOC. The vehicle engine controls the charging and discharging of the battery using the secondary corrected target SOC as a reference value.

[0080] Step 106: Determine the output SOC sent by the vehicle controller according to the actual SOC and the battery SOC change.

[0081] In this embodiment, before the second correction, the output SOC of the vehicle controller is updated based on the actual SOC sent by the battery management system (BMS). After the second correction, the output SOC sent by the vehicle controller is no longer updated based on the actual SOC sent by the battery management system (BMS), but is instead determined by the actual SOC and the battery SOC change.

[0082] In one embodiment, the difference between the actual SOC and the battery SOC change is used as the output SOC sent by the vehicle controller.

[0083] In addition, this embodiment calculates an equivalent factor correction value based on the difference between the secondary corrected target SOC and the output SOC. This is then added to the equivalent factor reference value Sref to obtain the final equivalent factor S. The equivalent fuel consumption of the hybrid vehicle in pure electric mode, series mode, and parallel mode is then calculated based on the equivalent factors. Since a vehicle can only operate in one mode, the equivalent fuel consumption for each of the three operating modes is calculated based on the wheel-end torque demand, vehicle speed, and the speed ratios and torque capabilities of the various power components, after pre-allocation. The calculated equivalent fuel consumption for each of the three modes is corrected based on the current operating mode and vehicle speed, ultimately determining the next operating mode and torque distribution for the vehicle. This optimizes fuel consumption while reducing the frequency of mode switching or gear shifting.

[0084] Specifically, based on the driver's required torque at the current vehicle speed, the speed of the front and rear motors, the distribution ratio, and the efficiency of the front and rear motors, the required electric power of the drive motor is obtained. The required power of the accessories is added to obtain the total required battery power, as shown in formula (1). Then, the equivalent fuel consumption of the pure electric mode is calculated based on the current equivalent factor, as shown in formula (2). Based on the required battery power calculated based on the pure electric mode, the electric power of the ISG motor determined based on the rule is subtracted to obtain the required battery power in the series mode. This is then converted into equivalent fuel consumption using the equivalent factor, and the engine fuel consumption is added to obtain the equivalent fuel consumption in the series mode, as shown in formula (3). Formula (4) is the conversion relationship between the ISG motor power and the engine power. When the vehicle speed is higher than 65 km / h (determined by the vehicle hardware), the engine speed corresponding to the parallel mode is converted based on the current vehicle speed and the engine direct drive speed ratio. According to a certain engine torque step size, the available engine torque at this speed is divided into several groups. When the divided engine torque exceeds the driver's required torque, the front motor outputs negative torque to meet the driver's total required torque, and the power generation is calculated based on the front motor's speed and efficiency. When the divided engine torque is less than the driver's required torque, the rear motor outputs positive torque to meet the driver's total demand, and the required driving power is calculated based on the rear motor's speed and efficiency. When the divided engine torque is equal to the driver's required torque, it is the engine direct drive mode. It should be noted that when the drive motor does not output torque, the motor's no-load loss power needs to be added. The equivalent fuel consumption corresponding to multiple groups of parallel modes is calculated using formula (5) through the above calculation method, and the minimum equivalent fuel consumption is selected as the final equivalent fuel consumption of the parallel mode.

[0085] P batt,req (t) = P P3,req (t)+P P4,req (t)+P acsy (t) (1)

[0086]

[0087] P ISG,req (t) = P ice,req (t)·η ISG ·η trans (4)

[0088]

[0089] Where, and is the instantaneous equivalent fuel consumption rate of the vehicle in the three corresponding working modes (g / s); is the fuel consumption rate of the engine (g / s); is the equivalent fuel consumption rate corresponding to the required battery power (g / s); s(t) is the equivalent factor at the current moment; Q lhv is the lower calorific value of fuel (J / g); P acsy (t) is the electric power required by all accessories of the vehicle (W); P batt,req (t) is the current required battery power (W); P P3,req (t) and P P4,req (t) is the required electric power (W) of the drive motor calculated based on the driver's required torque, the front and rear motor torque distribution ratio, and the efficiency of the front and rear motors at their current speeds and voltages. This calculation method allows the equivalent fuel consumption under the three operating modes to be calculated simultaneously based on the current vehicle speed when the driver's total demand is determined. S ref is the reference value of the equivalent factor, η ISG is the ISG motor efficiency, P ISG,req (t) is the required electric power of the ISG motor, η trans is the efficiency of the transmission system, a is a constant, SOC obj is the target SOC, and SOC(t) is the SOC output by the vehicle controller.

[0090] In addition, it should be noted that if the vehicle power enable signal is not detected, it is equivalent to exiting the secondary correction or not activating the secondary correction. After that, the output SOC of the vehicle controller continues to be updated in real time by the actual SOC sent by the battery controller.

[0091] In summary, the embodiments of this specification provide a method for controlling battery balance under a WLTC cycle. The method involves obtaining temperature and altitude information when a vehicle enters a powered-on state. Based on the temperature and altitude information, the method determines a pre-calibrated primary correction interval, a balance interval, and ΔSOC, and performs a first correction on the preset initial target SOC to obtain a primary corrected target SOC. When the primary corrected target SOC is within the primary correction interval and a vehicle power enable signal is detected, the method obtains the actual SOC sent by the battery controller. When the actual SOC is within the balance interval, the method determines a secondary corrected target SOC based on the actual SOC and ΔSOC, which serves as a reference for controlling the charging and discharging of the battery by the vehicle engine. The method calculates the battery SOC change based on the voltage and current feedback from the battery controller. Based on the actual SOC and the battery SOC change, the method determines the output SOC sent by the vehicle controller. In this manner, the target SOC is corrected, and then battery balance control under the WLTC cycle is performed based on the corrected target SOC. For hybrid vehicles with large-capacity batteries that use an equivalent fuel consumption minimization strategy, compared to a fixed target SOC, the dependence on the vehicle's initial actual battery level before the start of the cycle is reduced, greatly increasing the probability of successful battery balance in the hybrid vehicle's CS battery retention test under the WLTC operating conditions, and shortening the number of rotating hub tests for the CS battery retention test. When the actual battery level is within the SOC balance range, the battery balance preconditioning test and the cold or hot engine CS battery retention test can be completed in a single test, improving the efficiency and robustness of the rotating hub test while reducing the cost of rotating hub development.

[0092] Based on the same inventive concept, combined Figure 2 As shown, an embodiment of the present invention further provides a power balance control device based on the WLTC working condition, including:

[0093] An acquisition unit, used to acquire temperature information and altitude information when the vehicle enters a power-on state;

[0094] a first correction unit, configured to determine a pre-calibrated first correction interval, a balance interval, and a ΔSOC based on the temperature information and the altitude information, and to perform a first correction on the preset initial target SOC to obtain a first-corrected target SOC; the ΔSOC being the difference between the fixed target SOC and the balance point SOC, as determined by tests at different temperatures and altitudes;

[0095] a detection unit, configured to obtain an actual SOC sent by a battery controller when the primary-corrected target SOC is within the primary-corrected interval and a vehicle power enable signal is detected;

[0096] a second correction unit, configured to determine a second-corrected target SOC based on the actual SOC and the ΔSOC when the actual SOC is in the equilibrium range, and use the second-corrected target SOC as a reference value for controlling charging and discharging of the battery by the vehicle engine;

[0097] The output unit is used to calculate the battery SOC change based on the voltage and current feedback from the battery controller; and determine the output SOC sent by the vehicle controller based on the actual SOC and the battery SOC change.

[0098] Optionally, the first correction unit is also used to:

[0099] performing temperature correction on the initial target SOC according to the temperature information to obtain a temperature-corrected initial target SOC;

[0100] The temperature-corrected initial target SOC is subjected to altitude correction according to the altitude information to obtain the first-corrected target SOC.

[0101] Optionally, the first correction unit is also used to:

[0102] When the ambient temperature is less than a preset threshold, selecting a minimum temperature from the battery temperature and the ambient temperature as a reference temperature, and performing temperature correction on the initial target SOC according to the reference temperature to obtain a temperature-corrected initial target SOC;

[0103] When the ambient temperature is greater than or equal to a preset threshold, a maximum temperature is selected from the battery temperature and the ambient temperature as a reference temperature, and the initial target SOC is temperature-corrected according to the reference temperature to obtain a temperature-corrected initial target SOC.

[0104] Optionally, the first correction unit is also used to:

[0105] According to the reference temperature, a match is performed in a preset temperature and SOC adjustment amount comparison table. If the match is successful, the initial target SOC is temperature-corrected according to the SOC adjustment amount corresponding to the successfully matched temperature to obtain the temperature-corrected initial target SOC, wherein the temperature and SOC adjustment amount comparison table includes temperatures and SOC adjustment amounts corresponding to the temperatures.

[0106] Optionally, the second revision unit is further used to:

[0107] The difference between the actual SOC and the ΔSOC is the secondary corrected target SOC.

[0108] Optionally, the output unit is also used to:

[0109] If the vehicle power enable signal is not detected, the output SOC sent by the vehicle controller is updated according to the actual SOC sent by the battery controller.

[0110] Optionally, the output unit is also used to:

[0111] Calculating the product of the voltage and current fed back by the battery controller, integrating the product with respect to time, and obtaining a total energy change of the battery;

[0112] The battery SOC change is calculated based on the battery total energy and the battery total energy change.

[0113] In summary, the embodiments of this specification provide a WLTC-based battery balancing control device. When a vehicle enters the power-on state, the device obtains temperature and altitude information. Based on the temperature and altitude information, it determines a pre-calibrated primary correction interval, a balancing interval, and ΔSOC, and performs a first correction on the preset initial target SOC to obtain a primary corrected target SOC. When the primary corrected target SOC is within the primary correction interval and a vehicle power enable signal is detected, the device obtains the actual SOC sent by the battery controller. When the actual SOC is within the balancing interval, the device determines a secondary corrected target SOC based on the actual SOC and ΔSOC, which serves as a reference value for controlling the charging and discharging of the battery by the vehicle engine. The device calculates the battery SOC change based on the voltage and current feedback from the battery controller. Finally, the device determines the output SOC sent by the vehicle controller based on the actual SOC and the battery SOC change. This reduces the initial battery charge requirement for battery balancing under WLTC conditions, enabling rapid balancing when performing a WLTC CS battery maintenance test within a certain battery charge range, thereby reducing the number of rotating drum tests.

[0114] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the power balance control device based on the WLTC working condition described above can refer to the corresponding process in the aforementioned method, and will not be elaborated here.

[0115] Based on the same inventive concept, an embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, the aforementioned power balance control method based on the WLTC condition is implemented.

[0116] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working process of the computer-readable storage medium described above can refer to the corresponding process in the aforementioned method, and will not be elaborated here.

[0117] Based on the same inventive concept, an embodiment of the present invention further provides a plug-in hybrid vehicle, comprising a vehicle body and a controller installed in the vehicle body, wherein the controller is configured to implement the aforementioned power balance control method based on the WLTC operating condition.

[0118] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working process of the vehicle controller described above can refer to the corresponding process in the aforementioned method and will not be elaborated here.

[0119] The above are merely various embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A power balance control method based on WLTC operating conditions, characterized in that: include: When the vehicle enters the power-on state, obtain temperature information and altitude information; Determining a pre-calibrated primary correction interval, equilibrium interval, and ΔSOC based on the temperature information and the altitude information, and performing a first correction on the preset initial target SOC to obtain a primary corrected target SOC; the ΔSOC is the difference between the fixed target SOC and the equilibrium point SOC tested and calibrated at different temperatures and altitudes; When the primary corrected target SOC is within the primary corrected range and a vehicle power enable signal is detected, obtaining an actual SOC sent by a battery controller; When the actual SOC is in the balance range, determining a secondary corrected target SOC based on the actual SOC and the ΔSOC, and using the secondary corrected target SOC as a reference value for controlling charging and discharging of the battery by the vehicle engine; Calculate the battery SOC change based on the voltage and current feedback from the battery controller; The output SOC sent by the vehicle controller is determined according to the actual SOC and the battery SOC change.

2. The method according to claim 1, characterized in that The first correction of the preset initial target SOC to obtain a corrected target SOC includes: performing temperature correction on the initial target SOC according to the temperature information to obtain a temperature-corrected initial target SOC; The temperature-corrected initial target SOC is subjected to altitude correction according to the altitude information to obtain the first-corrected target SOC.

3. The method according to claim 2, characterized in that The temperature information includes battery temperature and ambient temperature; The step of performing temperature correction on the initial target SOC according to the temperature information to obtain the temperature-corrected initial target SOC includes: When the ambient temperature is less than a preset threshold, selecting a minimum temperature from the battery temperature and the ambient temperature as a reference temperature, and performing temperature correction on the initial target SOC according to the reference temperature to obtain a temperature-corrected initial target SOC; When the ambient temperature is greater than or equal to a preset threshold, a maximum temperature is selected from the battery temperature and the ambient temperature as a reference temperature, and the initial target SOC is temperature-corrected according to the reference temperature to obtain a temperature-corrected initial target SOC.

4. The method according to claim 3, characterized in that The step of performing temperature correction on the initial target SOC according to the reference temperature to obtain the temperature-corrected initial target SOC includes: According to the reference temperature, a match is performed in a preset temperature and SOC adjustment amount comparison table. If the match is successful, the initial target SOC is temperature-corrected according to the SOC adjustment amount corresponding to the successfully matched temperature to obtain the temperature-corrected initial target SOC, wherein the temperature and SOC adjustment amount comparison table includes temperatures and SOC adjustment amounts corresponding to the temperatures.

5. The method according to claim 1, wherein The determining of the secondary corrected target SOC according to the actual SOC and the ΔSOC includes: The difference between the actual SOC and the ΔSOC is the secondary corrected target SOC.

6. The method according to claim 1, wherein The method further comprises: If the vehicle power enable signal is not detected, the output SOC sent by the vehicle controller is updated according to the actual SOC sent by the battery controller.

7. The method according to claim 1, characterized in that The battery SOC change calculated based on the voltage and current fed back by the battery controller includes: Calculating the product of the voltage and current fed back by the battery controller, integrating the product with respect to time, and obtaining a total energy change of the battery; The battery SOC change is calculated based on the battery total energy and the battery total energy change.

8. A power balance control device based on WLTC working condition, characterized in that: include: An acquisition unit, used to acquire temperature information and altitude information when the vehicle enters a power-on state; a first correction unit, configured to determine a pre-calibrated first correction interval, a balance interval, and a ΔSOC based on the temperature information and the altitude information, and to perform a first correction on the preset initial target SOC to obtain a first-corrected target SOC; the ΔSOC being the difference between the fixed target SOC and the balance point SOC, as determined by tests at different temperatures and altitudes; a detection unit, configured to obtain an actual SOC sent by a battery controller when the primary-corrected target SOC is within the primary-corrected interval and a vehicle power enable signal is detected; a second correction unit, configured to determine a second-corrected target SOC based on the actual SOC and the ΔSOC when the actual SOC is in the equilibrium range, and use the second-corrected target SOC as a reference value for controlling charging and discharging of the battery by the vehicle engine; The output unit is used to calculate the battery SOC change based on the voltage and current feedback from the battery controller; The output SOC sent by the vehicle controller is determined according to the actual SOC and the battery SOC change.

9. A computer-readable storage medium, characterized in that A computer program is stored thereon, and when the program is executed by a processor, the power balancing control method based on the WLTC operating condition as described in any one of claims 1 to 7 is implemented.

10. A plug-in hybrid vehicle, characterized in that: The plug-in hybrid vehicle includes a vehicle body and a controller installed in the vehicle body, wherein the controller executes the power balance control method based on the WLTC operating condition according to any one of claims 1 to 7.

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