CN-121742445-B - Method and system for testing whole controller of electric vehicle

CN121742445BCN 121742445 BCN121742445 BCN 121742445BCN-121742445-B

Abstract

The application relates to the technical field of electric vehicle testing, and discloses a method and a system for testing an electric vehicle controller, wherein the method comprises the steps of firstly establishing an electrothermal impedance hysteresis model aiming at the physical characteristics of a load to be tested; the method comprises the steps of capturing a critical boundary value through monitoring steady-state switching actions of output signals, superposing dynamic disturbance signals containing orthogonal components to construct a composite excitation signal, enabling a vehicle controller to operate in a critical state, calculating effective thermal stress power in a sliding time window according to a voltage change rate, calculating a virtual internal temperature and a target equivalent impedance value in real time through an electrothermal impedance hysteresis model, simulating the target equivalent impedance value through adjusting physical input impedance, and monitoring convergence trend of the virtual internal temperature and switching frequency of a control state to judge logic stability. According to the application, by reconstructing the thermal inertia of the load, introducing orthogonal disturbance and high-frequency loss correction, the accurate assessment of the control stability of the whole vehicle controller under the complex electric heating coupling working condition is realized.

Inventors

LUO WEI
Pan Shikang
CHEN MENGXIANG
WANG ZHEN
ZHANG HAILIANG
XU WENYONG

Assignees

华东交通大学
扬州五新时峰智能科技有限公司

Dates

Publication Date: 20260505
Application Date: 20260228

Claims (9)

1. The test method of the whole electric vehicle controller is characterized by comprising the following steps of: Initializing a test environment, and establishing an electrothermal impedance hysteresis model aiming at the physical characteristics of a load to be tested; inputting a continuously-changing excitation signal to the whole vehicle controller, and capturing and recording a critical boundary value triggering logic overturning by monitoring steady-state switching action of the output signal of the whole vehicle controller; Generating a dynamic disturbance signal containing orthogonal components by taking the critical boundary value as a static reference value, superposing the dynamic disturbance signal to the static reference value to form a composite excitation signal, and inputting the composite excitation signal to the whole vehicle controller to enable the whole vehicle controller to operate in a critical state; Collecting voltage and current data of the whole vehicle controller, and calculating effective thermal stress power in a sliding time window according to the voltage change rate; Operating the electrothermal impedance hysteresis model, calculating a virtual internal temperature according to the effective thermal stress power, calculating a target equivalent impedance value based on the virtual internal temperature, and simulating the target equivalent impedance value by adjusting physical input impedance; The control logic stability of the vehicle controller is determined by continuously monitoring the convergence trend of the virtual internal temperature and the switching frequency of the control state, wherein, The establishment of the electrothermal impedance hysteresis model aiming at the physical characteristics of the load to be measured specifically comprises the following steps: The method comprises the steps of calling a pre-stored configuration file, extracting a virtual heat capacity, a virtual thermal resistance, a nominal impedance value and a resistance temperature coefficient, and defining a thermal time constant according to the product of the virtual heat capacity and the virtual thermal resistance, wherein the response time of the thermal time constant is limited to be larger than that of load simulation hardware; constructing a thermal balance differential equation, wherein the thermal balance differential equation takes effective thermal stress power as an input variable, simulates a thermal inertia physical process through integral operation, and converts transient power fluctuation into a smooth convergence trend of virtual internal temperature; And constructing an impedance mapping equation, wherein the impedance mapping equation uses the calculated virtual internal temperature as an independent variable, and the target equivalent impedance value which dynamically drifts along with the temperature is deduced by combining the resistance temperature coefficient and the nominal impedance value, and the electrothermal impedance hysteresis model comprises a thermal balance differential equation and an impedance mapping equation.
2. The method for testing the whole electric vehicle controller according to claim 1, wherein capturing and recording the critical boundary value triggering the logic flip specifically comprises: constructing a discrete excitation sequence which is stepwise increased or decreased in time domain, wherein the excitation signal value of each stepping period is generated based on the superposition of the excitation signal value at the previous moment and a preset scanning step length, and the scanning step length is set to be smaller than the minimum detection precision of the whole vehicle controller; substituting the normalized output signal of the whole vehicle controller into a state difference function to perform real-time operation, and quantifying the variation amplitude of the output state by calculating the difference between adjacent steady-state sampling points; And once the calculation result of the state difference function exceeds a preset state switching judgment threshold value, judging that logic overturn occurs, immediately locking and extracting the excitation signal value at the current moment, and defining the excitation signal value at the current moment as a static direct current working point of a subsequent closed loop test, wherein the excitation signal value at the current moment is a critical boundary value.
3. The method for testing the whole electric vehicle controller according to claim 1, wherein the generating the dynamic disturbance signal including the orthogonal component and superimposing the dynamic disturbance signal on the static reference value specifically includes: selecting two alternating current components which are prime numbers each other and have a frequency higher than the closed-loop bandwidth of a control algorithm, and constructing a digital waveform of a dynamic disturbance signal under the condition of phase orthogonality by using a waveform synthesis algorithm; Generating a random initial phase angle by a pseudo-random number generator and adding the random initial phase angle to a digital waveform of the dynamic disturbance signal to construct a dynamic disturbance sequence with a differential initial state; Superposing and synthesizing the dynamic disturbance sequence and the static reference value to obtain a digital sequence of a composite excitation signal; the digital sequence of the composite excitation signal is converted into a physical electric signal through digital-to-analog conversion and power amplification links, a stress field which continuously fluctuates around a state switching judging threshold value is constructed at the input end of the whole vehicle controller, and the high-frequency switching behavior of the control logic is excited.
4. The method for testing the whole electric vehicle controller according to claim 1, wherein the calculating the effective thermal stress power in the sliding time window according to the voltage change rate specifically comprises: Performing first-order differential operation on the collected voltage data of the load to be tested to obtain a voltage change rate, and comparing the voltage change rate with a voltage change rate threshold, wherein the voltage change rate threshold is determined according to the limit of a linear amplification region and a saturation region of the power device; Generating an oscillation weighting factor according to comparison fruits, wherein when the voltage change rate exceeds the voltage change rate threshold, the judging circuit is in a high-frequency switch state, a preset high-frequency loss coefficient is called as the oscillation weighting factor, and otherwise, the oscillation weighting factor is set as a unit value; And within a set sliding time window, carrying out weighted integration on the product of the voltage data and the current data by utilizing the oscillation weighting factor, so as to convert the high-frequency switching loss and the skin effect loss into the increment of the effective thermal stress power.
5. The method for testing the whole electric vehicle controller according to claim 1, wherein the running the electrothermal impedance hysteresis model calculates a virtual internal temperature according to an effective thermal stress power, and calculates a target equivalent impedance value based on the virtual internal temperature, specifically comprising: Calling a thermal balance differential equation, performing real-time calculation by adopting a discrete difference method, taking the virtual internal temperature of the last calculation step length as a state quantity, taking the currently calculated effective thermal stress power as an input variable, and calculating the virtual internal temperature at the current moment through numerical integration iteration; substituting the virtual internal temperature into an impedance mapping equation, calculating impedance drift through the linear equation if the load to be measured is of a linear type, and calling an impedance-temperature characteristic curve data table through a table lookup method if the load to be measured is of a nonlinear type to obtain a corresponding target equivalent impedance value based on the impedance drift and a nominal impedance value; and executing safe limiting processing on the calculated target equivalent impedance value to obtain an impedance instruction, and limiting the finally output impedance instruction within a safe interval defined by a short-circuit protection threshold value and an open-circuit protection threshold value of the whole vehicle controller.
6. The method for testing an electric vehicle controller according to claim 1, wherein the determining the control logic stability of the electric vehicle controller further comprises: Extracting a virtual internal temperature sequence in an observation time window, identifying local peaks and valleys of waveforms of the virtual internal temperature sequence through extremum searching so as to define continuous oscillation periods on a time domain, and calculating amplitude ratio of adjacent oscillation periods to generate oscillation attenuation rate; And comparing the calculated oscillation attenuation rate with a qualification judgment threshold value, namely judging that the vehicle controller is in thermal convergence if the oscillation attenuation rate is smaller than the qualification judgment threshold value, and judging that the vehicle controller is in thermal runaway risk and terminating the test if the oscillation attenuation rate is larger than or equal to the qualification judgment threshold value.
7. The method for testing the electric vehicle controller according to claim 6, wherein the determining the control logic stability of the electric vehicle controller further comprises a double verification based on the state flip density: counting the total times of logic level switching of the output signal of the whole vehicle controller in the observation time window, and dividing the total times by the duration of the observation time window to generate state turnover density; comparing the state flip density with a logic stability threshold value determined according to the physical life of the executive device; and only when the judged oscillation attenuation rate is qualified and the state turnover density is simultaneously lower than the logic stability threshold value, confirming that the whole vehicle controller is stable on the thermodynamic macroscopic level and the logic microscopic level, and judging that the whole vehicle controller passes the test.
8. A method of testing an electric vehicle controller according to claim 3, wherein the setting of the amplitude of the ac component in the generation of the dynamic disturbance signal containing the quadrature component follows the following constraint: setting an upper limit constraint for the frequency of an alternating current component, wherein the frequency is required to be lower than the cutoff frequency of a hardware low-pass filter at the input end of the whole vehicle controller; in the digital-to-analog conversion link, setting the update rate of the digital-to-analog converter to be more than ten times of the highest frequency in the alternating current component; In the signal driving link, the bandwidth of the linear power amplifying circuit is configured to cover the range of direct current to kilohertz and has the characteristic of low output impedance.
9. A test system for an electric vehicle controller, applied to the test method for the electric vehicle controller according to any one of claims 1 to 8, characterized by comprising: The main control module is used for initializing a test environment, establishing an electrothermal impedance hysteresis model, receiving voltage data fed back by the data acquisition module, calculating a voltage change rate according to the voltage data, calculating effective thermal stress power, operating the electrothermal impedance hysteresis model to solve a virtual internal temperature and a target equivalent impedance value in real time, generating and transmitting a corresponding impedance instruction to the load simulation module, and judging the control logic stability of the whole electric vehicle controller according to the convergence trend of the virtual internal temperature and the switching frequency of a control state; The simulation module is used for running the vehicle dynamics model and interacting with the whole vehicle controller through the vehicle communication bus, sending a wake-up message and a vehicle speed simulation signal to the whole vehicle controller, and enabling a functional loop of the whole vehicle controller to be tested to be in an activated standby state; The excitation injection module is used for responding to the instruction of the main control module, outputting a discrete excitation sequence which changes in a step shape at the stage of acquiring a critical boundary value, generating a composite excitation signal which comprises orthogonal components and is overlapped on a static reference value at the closed loop test stage, and driving the whole vehicle controller to operate in a critical state; The data acquisition module is used for monitoring the output signal state of the whole vehicle controller in real time to identify a logic overturning action, and synchronously acquiring voltage and current data applied to two ends of the load simulation module by the whole vehicle controller and transmitting the voltage and current data to the main control module; the load simulation module is used for receiving the impedance instruction sent by the main control module, dynamically adjusting the physical input impedance of the load simulation module, and simulating the calculated target equivalent impedance value.

Description

Method and system for testing whole controller of electric vehicle Technical Field The invention relates to the technical field of electric vehicle testing, in particular to a method and a system for testing an electric vehicle controller. Background The whole electric automobile controller is used as a core unit for energy management and is responsible for scheduling the operation of various high-voltage accessories and power loads. Under the complex working condition of the electric vehicle, the physical characteristics of high-power components such as the PTC heater, the motor stator coil and the like can be obviously changed along with temperature accumulation, and the stability of a control loop is directly affected. Existing test schemes commonly employ a general-purpose programmable electronic load to act as an analog terminal for the object under test. In the test process, the system injects analog signals into the VCU and controls the electronic load to present specific resistance or voltage characteristics according to preset values. In order to detect the logic threshold of the controller, a linear scanning mode is generally adopted, that is, a monotonically increasing or decreasing voltage signal is applied to the input end, and the inversion point of the output state is observed. For power assessment, the instantaneous values of voltage and current are read out more directly, and the energy consumed by the load is monitored by conventional product operation. However, in the existing test of the whole electric vehicle controller, the response speed of the general electronic load is extremely high, and the impedance switching is almost instantaneously completed. The real physical device is affected by heat capacity, the impedance change has hysteresis, the two have serious mismatch on the time scale, the risk of low-frequency oscillation caused by heat hysteresis is easily covered, the interference test is carried out by adopting a single frequency signal, the signal frequency is easily overlapped with the sampling frequency of the controller, and the logic defect in a metastable state is missed. The traditional average power algorithm only focuses on steady-state values, and in a critical area where control logic is frequently switched, high-frequency switching loss is filtered by a smoothing algorithm, and the actual thermal stress is underestimated by the calculation mode, so that the physical boundary of thermal runaway is difficult to accurately define. Therefore, the invention provides a test method and a test system for an electric vehicle controller, which are used for solving the defects in the prior art. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a test method and a test system of an electric vehicle controller, which solve the problems that the coupling effect between high-frequency logic switching and low-frequency thermal response cannot be effectively simulated in the test of the existing electric vehicle controller, and dead zone and thermal runaway boundary cannot be accurately positioned and controlled. In order to achieve the above purpose, the invention is realized by the following technical scheme: the first aspect of the invention provides a test method of an electric vehicle controller, comprising the following steps: Initializing a test environment, and establishing an electrothermal impedance hysteresis model aiming at the physical characteristics of a load to be tested; inputting a continuously-changing excitation signal to the whole vehicle controller, and capturing and recording a critical boundary value triggering logic overturning by monitoring steady-state switching action of the output signal of the whole vehicle controller; Generating a dynamic disturbance signal containing orthogonal components by taking the critical boundary value as a static reference value, superposing the dynamic disturbance signal to the static reference value to form a composite excitation signal, and inputting the composite excitation signal to the whole vehicle controller to enable the whole vehicle controller to operate in a critical state; Collecting voltage and current data of the whole vehicle controller, and calculating effective thermal stress power in a sliding time window according to the voltage change rate; Operating the electrothermal impedance hysteresis model, calculating a virtual internal temperature according to the effective thermal stress power, calculating a target equivalent impedance value based on the virtual internal temperature, and simulating the target equivalent impedance value by adjusting physical input impedance; And judging the control logic stability of the whole vehicle controller by continuously monitoring the convergence trend of the virtual internal temperature and the switching frequency of the control state. Preferably, the building of the electrothermal impedance hysteresis model for the physical characteris