Research on the Motor Mode Control based on the Shut off Test in Dual Motor Hybrid System

<div class="section abstract"><div class="htmlview paragraph">In order to improve the safety and reliability of the inverter used in hybrid vehicles and reduce the risk of inverter failure, based on the functional safety ISO26262 development process and software architecture, a safe shutdown path scheme is designed in this paper. Firstly, after entering the initialization mode, on the basis of adding the inverter control signal feedback mechanism on the inverter control system, this scheme designs the control methods and specific processes of the shutdown path test and insulation detection. The shutdown path test and insulation detection designed in this scheme are implemented during the control initialization process, including designing the hardware diagnostic safety mechanism and the unique output shutdown path test method. If the shutdown path test or insulation detection fails, the risk of IGBT out of control can be avoided; the detection mechanism of this system can effectively reduce the failure rate and potential failure rate of faults. Secondly, the shut-off path test steps are divided into five steps: PWM test, open test, upper bridge short-circuit test, lower bridge short-circuit test, and open test. And under this condition, tests are carried out on the vehicle. Finally, the test results show that this scheme improves the coverage of the shutdown path diagnosis and can diagnose the potential faults of the inverter, verifying the feasibility of the scheme. The addition of standby control mode can avoid the disadvantage that when a collision occurs or the motor exceeds the maximum speed threshold or the motor speed exceeds the threshold, the three-phase bridge arm is closed, and the motor back emf exists, causing the motor current to flow through the IGBT diode to rectify to the battery, generating a large braking torque and causing the battery to overcharge.</div></div>