A whole vehicle road level balance simulation method and system

Abstract

The application discloses a kind of whole vehicle road electric balance simulation method systems, comprising: the battery of target whole vehicle is identified offline, constructs battery model;The generator of target whole vehicle is tested, constructs generator model;Based on the running result of the environmental bin rotating drum to the preset working condition road spectrum constructs working condition road spectrum model;According to the load characteristic of the load of target whole vehicle, and set the load loading timing of load, constructs load switch model;According to the battery model, the generator model, the working condition road spectrum model and the load switch model constructs the running circuit model of target whole vehicle, based on the running circuit model to target whole vehicle carries out electric balance simulation.The application compared with prior art, in the process of running circuit model building, introduce intelligent generator charge-discharge strategy, battery charge-discharge strategy and dynamic load management strategy etc., greatly improve the accuracy of model.

Description

Technical Field

[0001] This invention relates to the technical field of automotive low-voltage power supply systems, and in particular to a method and system for simulating the road electrical balance of a vehicle. Background Technology

[0002] The electrical balance of a vehicle's power system is divided into two parts: dynamic electrical balance and static electrical balance. Dynamic electrical balance is crucial in power system design. When a car is in motion, the varying frequencies of use of electrical appliances, different seasons, climates, times of day, and different user habits all create different combinations of electrical appliance usage, resulting in varying power demands. For traditional gasoline-powered vehicles, the purpose of dynamic electrical balance design is to calculate the vehicle's electrical load table based on the vehicle's model positioning and configuration, matching the alternator, electrical load, and battery to achieve a balance between power supply and demand when the vehicle is running or idling, and to maintain the battery charge within a suitable range. With social development and technological progress, the number of electrical devices in automobiles is increasing daily. Therefore, in the design of automotive electrical systems, the electrical balance of the entire vehicle's electrical system must be calculated scientifically and rationally.

[0003] Currently, vehicle electrical balancing primarily involves testing actual vehicles to determine their electrical balance performance. A significant drawback of this method is the long testing and adjustment times, resulting in high testing costs. To overcome these issues, some industry players have adopted simulation models to model the vehicle's electrical balance performance. Since the accuracy of the simulation model directly affects the overall vehicle electrical balancing simulation accuracy and thus the vehicle's electrical balance performance, a high-accuracy vehicle electrical balancing model needs to be designed. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in the aforementioned technologies. Therefore, the purpose of this invention is to propose a vehicle road electrical balance simulation method and system based on a generator model considering the relationship between generator temperature and engine speed, a load switching model separating fixed loads and switching loads, and a battery model based on the Kalman filter algorithm, with the aim of improving the simulation accuracy of the vehicle road electrical balance simulation model.

[0005] To achieve the above objectives, the first aspect of this invention proposes a vehicle road electrical balance simulation method, comprising:

[0006] Offline identification of the target vehicle's battery is performed to construct a battery model;

[0007] The generator of the target vehicle was tested, and a generator model was constructed.

[0008] A working condition road spectrum model is constructed based on the operation results of the environmental chamber drum on the preset working condition road spectrum.

[0009] Based on the load characteristics of the target vehicle and the load loading sequence of the load, a load switching model is constructed.

[0010] The operating circuit model of the target vehicle is constructed based on the battery model, the generator model, the operating condition spectrum model and the load switch model, and the electrical balance simulation of the target vehicle is performed based on the operating circuit model.

[0011] Preferably, the battery model, the generator model, the operating condition spectrum model, the load switch model, and the operating circuit model are constructed in the Simulink environment.

[0012] Preferably, the battery of the target vehicle is identified offline, and a battery model is constructed, including:

[0013] The battery is subjected to a capacity test to obtain a correction relationship between the actual capacity and the nominal capacity of the battery at different temperatures;

[0014] Construct an equivalent battery model based on the battery parameters of the battery.

[0015] The equivalent circuit parameters of the battery are obtained based on offline identification.

[0016] Substitute the equivalent circuit parameters into the equivalent circuit model to construct the second-order equivalent RC circuit model of the battery, and construct the battery model based on the Kalman filtering algorithm, the correction relation, and the second-order equivalent RC circuit model.

[0017] Preferably, the generator of the target vehicle is tested, and a generator model is constructed, including:

[0018] The generator was tested to obtain generator test data;

[0019] Interpolate the generator test data to obtain a first correspondence between the generator's state parameters and output parameters; wherein the state parameters include temperature, speed, and output voltage; and the output parameter is the output current.

[0020] Based on the first correspondence, the generator is used as a variable current source whose output varies with the load to construct the generator model.

[0021] Preferably, a working condition road spectrum model is constructed based on the operating results of the environmental chamber drum on the preset working condition road spectrum, including:

[0022] The preset operating condition path spectrum is operated by rotating the drum in the environmental chamber;

[0023] When the preset operating condition road spectrum is run, a second correspondence is obtained between the engine speed data, generator temperature data and running time of the target vehicle;

[0024] Obtain the generator-engine speed ratio of the target vehicle;

[0025] Based on the generator-engine speed ratio, the generator speed data in the second correspondence is converted into generator speed data to obtain a third correspondence between the generator speed data, generator temperature data, and running time of the target vehicle; the third correspondence is the output characteristic of the generator.

[0026] The operating condition road spectrum model is constructed based on the output characteristics of the generator.

[0027] Preferably, the target vehicle electrical load includes: vehicle switch load and vehicle fixed load; the vehicle switch load is a load controlled by a load switch in the vehicle; the vehicle fixed load is a load that is not controlled by a switch after the target vehicle is started.

[0028] Preferably, based on the load characteristics of the target vehicle's load and setting the load loading sequence of the load, a load switching model is constructed, including:

[0029] Set the load loading sequence for each vehicle switch in the target vehicle;

[0030] Determine the load parameters for each vehicle switch load; the load parameters include: load type, load operating current, and load operating time;

[0031] The vehicle switch load requirements are determined based on the load loading sequence and the load parameters.

[0032] The target vehicle is tested, and the engine speed data and fixed load current data of the target vehicle are collected and fitted to obtain the fourth correspondence between the engine speed and fixed load current of the target vehicle.

[0033] The fixed load requirement of the whole vehicle is determined according to the fourth correspondence relationship;

[0034] The load switch model is constructed based on the vehicle's switch load requirements and the vehicle's fixed load requirements.

[0035] Preferably, when performing electrical balance simulation on the target vehicle, the state parameters and input / output parameters of the battery model, the generator model, the operating condition spectrum model, the load switch model, and the operating circuit model of the target vehicle are output in real time.

[0036] A second aspect of this invention provides a vehicle road electrical balance simulation system constructed based on any of the above methods, comprising: a battery model, a generator model, a road spectrum model under operating conditions, a load switch model, an operating circuit model, and an output model; wherein,

[0037] The battery model is used to simulate the changes in battery parameters of the target vehicle.

[0038] The generator model is used to read the generator output characteristics in the operating condition road spectrum model, and to simulate the changes in the output current and output voltage of the generator of the target vehicle in real time based on the generator output characteristics.

[0039] The load switch model is used to simulate the load requirements of the target vehicle.

[0040] The operating circuit model is used to process the input and output signals of each model in the simulation system based on the electric balance strategy of the target vehicle, and calculate the electric balance information of the target vehicle; wherein, the electric balance strategy includes: battery charging acceptance capability, generator output strategy and dynamic load strategy.

[0041] Preferably, when the battery model simulates the changes in battery parameters of the target vehicle, the battery parameters are identified online based on the changes in the input parameters, output parameters, and state parameters of the battery using an extended Kalman filter algorithm.

[0042] Compared with existing technologies, the advantages of this invention are as follows: It innovatively builds a generator model in Simulink software, adjusting the input current of the generator model in real time based on the input generator temperature and engine speed; it divides the load model into two parts: a fixed load and a vehicle switching load, resulting in more accurate load model results; the battery model adopts a second-order RC equivalent circuit model, combined with a Kalman filter algorithm, which is more accurate than the traditional ampere-hour integration method, and incorporates a limit on the maximum charging capacity of the battery; during the construction of the operating circuit model, it introduces intelligent generator charging and discharging strategies, battery charging and discharging strategies, and dynamic load management strategies, greatly improving the accuracy of the model.

[0043] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0044] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0045] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0046] Figure 1 This is a schematic diagram of the vehicle road electrical balance simulation method;

[0047] Figure 2 A schematic diagram illustrating parameter identification during the construction of a battery model;

[0048] Figure 3 This is a schematic diagram showing the relationship between generator temperature and speed under a certain operating condition.

[0049] Figure 4 For the whole vehicle switch load model and switch control model;

[0050] Figure 5 This is a schematic diagram of the motor current output characteristics during a vehicle road electrical balance simulation.

[0051] Figure 6 This is a schematic diagram of the motor voltage output characteristics during a vehicle road electrical balance simulation.

[0052] Figure 7 This is a schematic diagram of the load current characteristics during a vehicle road electrical balance simulation.

[0053] Figure 8 This is a schematic diagram of the battery voltage characteristics during a vehicle road electrical balance simulation.

[0054] Figure 9 This is a schematic diagram of the battery SOC parameters during vehicle road electrical balance simulation.

[0055] Figure 10 This is a schematic diagram of the battery current characteristics during a vehicle road electrical balance simulation. Detailed Implementation

[0056] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0057] like Figure 1 As shown, this invention provides a method for simulating the road electrical balance of a vehicle, including:

[0058] Offline identification of the target vehicle's battery is performed to construct a battery model;

[0059] The generator of the target vehicle was tested, and a generator model was constructed.

[0060] A working condition road spectrum model is constructed based on the operation results of the environmental chamber drum on the preset working condition road spectrum.

[0061] Based on the load characteristics of the target vehicle and the load loading sequence of the load, a load switching model is constructed.

[0062] The operating circuit model of the target vehicle is constructed based on the battery model, the generator model, the operating condition spectrum model and the load switch model, and the electrical balance simulation of the target vehicle is performed based on the operating circuit model.

[0063] The vehicle road electrical balance simulation system constructed based on the above-mentioned vehicle road electrical balance simulation method includes: a battery model, a generator model, a road spectrum model under operating conditions, a load switch model, an operating circuit model, and an output model; among which,

[0064] The battery model is used to simulate the changes in battery parameters of the target vehicle.

[0065] The generator model is used to read the generator output characteristics in the operating condition road spectrum model, and to simulate the changes in the output current and output voltage of the generator of the target vehicle in real time based on the generator output characteristics.

[0066] The load switch model is used to simulate the load requirements of the target vehicle.

[0067] The operating circuit model is used to process the input and output signals of each model in the simulation system based on the electric balance strategy of the target vehicle, and calculate the electric balance information of the target vehicle; wherein, the electric balance strategy includes: battery charging acceptance capability, generator output strategy and dynamic load strategy.

[0068] In an embodiment of the present invention, constructing a battery model includes: firstly, performing HPPC pulse charge-discharge tests at different currents and temperatures, and OCV tests at different temperatures on the battery; then, using an algorithm, identifying parameters such as the battery's equivalent resistance and equivalent capacitance, and inputting these parameters into the battery's second-order RC equivalent circuit model. During the actual operation of the model, based on changes in the battery's current, voltage, and temperature, an extended Kalman filter algorithm is used to identify parameters such as the battery's state of charge (SOC) online, and outputting these parameters to the operating circuit model.

[0069] In other embodiments of the present invention, the method for constructing a battery model includes: obtaining an equivalent circuit model of the battery using an offline identification method; firstly, performing a capacity test on the battery to obtain the correction relationship between the actual capacity and the nominal capacity of the battery at different temperatures; using data such as the battery internal resistance provided by the battery manufacturer to provide initial parameters for the battery equivalent model; and using pulse discharge to obtain battery voltage and current data as identification inputs. A schematic diagram of parameter identification during battery model construction is shown below. Figure 2As shown, a physical model of the battery is built in Simulink, the equivalent model parameters of the battery are identified using Parameter EstimatorAPP, and a second-order equivalent RC circuit model of the battery is constructed.

[0070] In an embodiment of the present invention, constructing a working condition road spectrum model includes: deriving the engine speed and generator temperature at different times by running a specific working condition road spectrum in an environmental chamber with a rotating drum, wherein the engine and generator are connected by a belt, and the generator speed can be obtained by multiplying the engine speed by the corresponding speed ratio.

[0071] In this embodiment of the invention, constructing a generator model includes: conducting experimental tests on the generator, and using Simulink's lookup table tool to interpolate and calculate the generator output based on the experimental results. This requires obtaining data such as the generator's temperature, speed, and output voltage during testing and establishing a lookup table to correlate these data with the generator's actual output current. The generator modeling approach treats the generator as a variable current source, adjusting its output current and voltage according to changes in the vehicle load current: when the vehicle load power demand is met, the generator adjusts its output power based on the required current; when the vehicle load demand is excessive, the generator outputs voltage at its maximum nominal power. The generator model reads generator speed and temperature information from the operating condition road spectrum model and combines this with the generator output characteristic MAP diagram to adjust the generator's output current and voltage in real time based on temperature and speed, and sends the data to the operating circuit model. Figure 3 This is a schematic diagram of the generator temperature curve and generator speed curve and their corresponding relationship given in the embodiment of the present invention. The horizontal axis of the figure represents the test time, the vertical axis of the generator temperature curve represents the temperature, and the vertical axis of the generator speed curve represents the speed.

[0072] In embodiments of this invention, a load switching model is constructed, comprising: vehicle load divided into two parts: vehicle basic load and vehicle switching load. The vehicle basic load is the load that automatically turns on after vehicle startup and is not controlled by a switch. By collecting the values ​​of the basic load current at different vehicle speeds, and through a fitting function, the current of the basic load can be directly called according to the engine speed in the simulation model. The vehicle switching load is the load on the vehicle that customers can turn on and off via switches. By analyzing the electrical characteristics and working principles of the vehicle loads, the load type (inductive, resistive, or capacitive), load operating current (I-load), and load operating time are determined. The opening sequence and opening time of the loads are simulated by setting the loading sequence of each electrical load. Under different operating conditions, different load switching sequences are selected to control the switching state of each load. The vehicle switching loads mainly include air conditioning, blower, headlights, seat adjustment, heating and ventilation, wipers, and washer pumps, which are further divided into resistive and inductive loads. Different types of load models are built according to the different load types. The basic load of the vehicle mainly includes engine-related loads, instruments, main unit, coolant pump, cooling fan, etc. Figure 4 This is a schematic diagram of the vehicle switch load model and switch control model given in the embodiment of the present invention. In the figure, L1, L2, and L3 represent load switches; M1 and M2 represent switch load models, which are controlled by their corresponding load switches and are used to calculate the load current based on the input power data and output it; M3 represents the basic load model, which is used to call the current of the basic load based on the engine speed and output it; ADD is used to sum the load currents output by M1, M2, and M3 and output it to the corresponding output module. By reading information such as engine speed and ambient temperature in the operating condition spectrum, the load current and other information are output in real time.

[0073] In embodiments of the present invention, a running circuit model is constructed, including a vehicle basic model that combines the generator, battery, load, and operating condition spectrum. This model implements intelligent generator strategies, battery charging and discharging strategies, and dynamic load management strategies to maximize the real-world power consumption of the vehicle. The running circuit model needs to process and summarize signals from the operating condition spectrum, battery, generator, and load models, combining data such as battery charging acceptance capability, generator step-down output, intelligent generator strategies, and dynamic load management strategies to calculate the actual voltage and current information of the vehicle's power supply and power consumption systems, and output this information through an output module. In other embodiments of the present invention, the output model is used to output real-time information such as the vehicle's load voltage and current, engine speed, generator temperature, generator voltage and current, battery voltage and current, and battery SOC during simulation. Figures 5-10The diagrams shown in sequence are: motor current output characteristic diagram, motor voltage output characteristic diagram, load current characteristic diagram, battery voltage characteristic diagram, battery SOC parameter diagram, and battery current characteristic diagram during vehicle road electrical balance simulation according to an embodiment of the present invention. Figure 5-10 middle, Figures 5-10 The horizontal axis represents time. Figure 5 The vertical axis represents the current intensity. Figure 6 The vertical axis represents voltage. Figure 7 The vertical axis represents the current intensity. Figure 8 The vertical axis represents voltage. Figure 9 The vertical axis represents the electrical quantity. Figure 10 The vertical axis represents the current intensity, and engineers can dynamically analyze the vehicle's electrical balance performance based on relevant information.

[0074] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for simulating the road electrical balance of a vehicle, characterized in that, include: Offline identification of the target vehicle's battery is performed to construct a battery model; The generator of the target vehicle was tested, and a generator model was constructed. A working condition road spectrum model is constructed based on the operation results of the environmental chamber drum on the preset working condition road spectrum. Based on the load characteristics of the target vehicle and the load loading sequence of the load, a load switching model is constructed. The operating circuit model of the target vehicle is constructed based on the battery model, the generator model, the operating condition spectrum model and the load switch model, and the electrical balance simulation of the target vehicle is performed based on the operating circuit model. Based on the load characteristics of the target vehicle and the load loading sequence of the load, a load switching model is constructed, including: Set the load loading sequence for each vehicle switch in the target vehicle; Determine the load parameters for each vehicle switch load; the load parameters include: load type, load operating current, and load operating time; The vehicle switch load requirements are determined based on the load loading sequence and the load parameters. The target vehicle is tested, and the engine speed data and fixed load current data of the target vehicle are collected and fitted to obtain the fourth correspondence between the engine speed and fixed load current of the target vehicle. The fixed load requirement of the whole vehicle is determined according to the fourth correspondence relationship; The load switch model is constructed based on the vehicle's switch load requirements and the vehicle's fixed load requirements.

2. The vehicle road electrical balance simulation method as described in claim 1, characterized in that, The battery model, the generator model, the operating condition spectrum model, the load switch model, and the operating circuit model are constructed in the Simulink environment.

3. The vehicle road electrical balance simulation method as described in claim 1, characterized in that, Offline identification of the target vehicle's battery and construction of a battery model, including: The battery is subjected to a capacity test to obtain a correction relationship between the actual capacity and the nominal capacity of the battery at different temperatures; Construct an equivalent battery model based on the battery parameters of the battery. The equivalent circuit parameters of the battery are obtained based on offline identification. Substitute the equivalent circuit parameters into the battery equivalent model to construct the second-order equivalent RC circuit model of the battery, and construct the battery model based on the Kalman filtering algorithm, the correction relationship, and the second-order equivalent RC circuit model.

4. The vehicle road electrical balance simulation method as described in claim 1, characterized in that, The generator of the target vehicle is tested, and a generator model is constructed, including: The generator was tested to obtain generator test data; Interpolate the generator test data to obtain a first correspondence between the generator's state parameters and output parameters; wherein the state parameters include temperature, speed, and output voltage; and the output parameter is the output current. Based on the first correspondence, the generator is used as a variable current source whose output varies with the load to construct the generator model.

5. The vehicle road electrical balance simulation method as described in claim 1, characterized in that, A working condition road spectrum model is constructed based on the operation results of the environmental chamber drum on the preset working condition road spectrum, including: The preset operating condition path spectrum is operated by rotating the drum in the environmental chamber; When the preset operating condition road spectrum is run, a second correspondence is obtained between the engine speed data, generator temperature data and running time of the target vehicle; Obtain the generator-engine speed ratio of the target vehicle; Based on the generator-engine speed ratio, the engine speed data in the second correspondence is converted into generator speed data to obtain a third correspondence between the generator speed data, generator temperature data, and running time of the target vehicle; the third correspondence represents the output characteristics of the generator. The operating condition road spectrum model is constructed based on the output characteristics of the generator.

6. The vehicle road electrical balance simulation method as described in claim 1, characterized in that, The load of the target vehicle includes: vehicle switch load and vehicle fixed load; the vehicle switch load is the load controlled by the load switch in the vehicle; the vehicle fixed load is the load that is not controlled by the switch after the target vehicle is started.

7. The vehicle road electrical balance simulation method as described in claim 1, characterized in that, When performing electrical balance simulation on the target vehicle, the state parameters and input / output parameters of the battery model, the generator model, the operating condition spectrum model, the load switch model, and the operating circuit model of the target vehicle are output in real time.

8. A vehicle road electric balance simulation system constructed based on the method of any one of claims 1-7, characterized in that, include: Battery model, generator model, operating condition spectrum model, load switch model, operating circuit model, and output model; among them, The battery model is used to simulate the changes in battery parameters of the target vehicle. The generator model is used to read the generator output characteristics in the operating condition road spectrum model, and to simulate the changes in the output current and output voltage of the generator of the target vehicle in real time based on the generator output characteristics. The load switch model is used to simulate the load requirements of the target vehicle. The operating circuit model is used to process the input and output signals of each model in the simulation system based on the electric balance strategy of the target vehicle, and calculate the electric balance information of the target vehicle; wherein, the electric balance strategy includes: battery charging acceptance capability, generator output strategy and dynamic load strategy.

9. The vehicle road electrical balance simulation system as described in claim 8, characterized in that, When the battery model simulates the changes in battery parameters of the target vehicle, it identifies the battery parameters online based on the changes in the battery's input parameters, output parameters, and state parameters using an extended Kalman filter algorithm.

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