Design Of Integrated Automatic Test System For Battery Energy Distribution Unit Of Electric Vehicle

Battery energy distribution unit（BDU）is an important part of the high voltage circuit of electric vehicles.It controls the up and down power process of the high voltage electrical circuit,the precharging process and the charging process.Whether the characteristic parameters of BDU meet the qualified conditions or not has an important impact on the service life of the vehicle,the control strategy and the safety of high voltage electricity.Normally,the test process for BDU parameters needs workers manually build the test environment.So,this paper is aiming at to solve the problem that there is no equipment that can realize automation and integration for BDU parameters test.In this paper,through summarizing the literature and market research on BDU system used by electric vehicles,the possible parameter anomalies of the multi-class contactors and multi-class current sensors are listed,and test requirements of the test system are proposed.Based on the analysis of the characteristics of each component and the characteristics of the electrical circuit of BDU itself,the basic testing principle,test circuit model and test method of each test item are put forward.In order to improve the test efficiency,the adaptive sampling window waiting time algorithm is used to maximize the test efficiency in the test process while maintaining the test accuracy.Based on the test model of each test item,combined with practice,the design method of overall online reconfiguration hardware circuit is proposed.According to the functional requirements,the selection and analysis of peripherals in the test system are carried out.In combination with practice,various kinds of test failures that may be encountered are dealt with by using isolation devices to process the hardware circuit,which improves the degree of decoupling between each test model and enhances the robustness and stability of the test system.At the same time,an information interaction architecture of hybrid bus is proposed to establish a channel for the communication between logic controller and actuator.In consideration of the application of differential sampling circuit,the RC filter circuit and sampling resistance matching of differential sampling circuit are designed again to improve the precision of parameter testing.In software system design,the software system is developed based on event-driven software architecture.A software system is established that the upper computer developed by Lab VIEW is the logic controller and the lower computer developed by C language in Code Warrior environment is the subordinate executor.At the same time,the software debugging mode is designed in the software.In this mode,the software system can run independently of the hardware system,which is convenient for developers to verify the logic.It is proved by practice that the software system proposed in this paper has friendly man-machine interaction interface,stable long-term operation and strong expansion ability.Finally,experiments are designed to verify the function,parameter test accuracy and test efficiency of the integrated automatic test system proposed in this paper.The system error generated in time parameter test and current accuracy test module is analyzed and a calibration method based on root mean square error is proposed.The experimental results show that the use of test system design is put forward in this paper,the parameters of the test precision can meet the accuracy requirement,and test efficiency relative to adopt the method of previous artificial structures,test environment for 10 to 15 minutes,reduced to 3 minutes,effectively solve the lack of the electric car BDU integration automatic test equipment.