Research On Fault Management Of Drive Motor Control System Based On Functional Safety

The drive motor control system is the source of power in pure electric vehicles,and is mainly responsible for controlling the motor to rotate forward and reverse as required.Different from traditional industrial motors,electric vehicle drive motors always need to face various complicated working conditions,and the chance of failure is more accidental.At the same time,the failure of the drive motor control system often brings non-initial predictive inverters.Boots affect the lives of drivers,passengers and pedestrians.Therefore,a fault management system is developed for unified management of faults related to the drive motor control system and functional safety.First,according to the concept phase of the road functional safety standard ISO 26262,a hazard analysis and risk assessment(HARA)analysis method is used to set the relevant items of the drive motor control system,hazard events,and corresponding safety goals.The analysis method of method(FTA)takes the violation of the safety target as the top item of the fault tree,and finds the fault that caused the violation of the safety target,and forms a functional safety requirement.Then,further analyze the fault generation mechanism,and use MATLAB/Simulink environment to model the system,and at the same time model and simulate the faults analyzed by FTA to verify that the functional safety requirements further replace the functional safety related faults.In terms of diagnostic communication,the diagnostic standards ISO 14229 and ISO 15765-2 are used to diagnose the application layer,session layer,transport layer and network layer of diagnostic communication.Then,a fault composed of diagnostic communication,fault diagnosis and fault protection is established.Management system.The diagnostic services,communication parameters,timers,etc.are defined in detail,and the standard ISO 15031-6 is adopted to define the fault diagnosis codes for the functional safety-related faults of the drive motor control system.In terms of fault diagnosis,a systematic diagnostic mechanism was designed with reference to the ISO 14229 diagnostic standard.At the same time,different diagnostic strategies were developed for specific faults,and simulations were performed for diagnostic diagnosis.Among them,the method of estimating position signal by synovial observer is used to construct the diagnosis strategy of position sensor fault;the current sensor fault diagnosis strategy is constructed by coordinate transformation method;the error voltage diagnosis method is used to diagnose the open-circuit fault of IGBT Design;Using direct measurement of voltage signals,a diagnostic strategy model for bus voltage and controller voltage was constructed.For the fault protection surface,a protection mechanism for functional safety related faults is designed by formulating the operation mode of the motor.Finally,based on the diagnostic tool chain of the vector company,a diagnostic database file was established and an automated test of UDS was performed to verify the reliability of the diagnostic communication.A hardware-in-the-loop fault injection test was performed on the MCU based on the VT system to verify the effectiveness of the fault management system.