Research on Motor Safety Monitoring Control for Powertrain Control System

The motor controller, as one of the important controllers in the electric drive system, may cause unexpected acceleration or deceleration of the vehicle by the driver due to systematic failure and random hardware failure. Conducting research on the functional safety of drive motors for new energy vehicles is of great significance for reducing the systematic failure and random hardware failure of the electric drive. This paper has carried out designs including the allowable motor torque design for safety monitoring, the motor torque prediction design for safety monitoring, the rationality judgment design of the motor torque for safety monitoring, the rationality judgment design of the motor direction for safety monitoring, the functional safety motor degradation design, and the active discharge state monitoring of the motor, so that the system can transition to a safe state when an error occurs. Among them, the motor torque prediction design for safety monitoring includes predicting the motor torque based on the current signal. The rationality judgment design of the motor torque for safety monitoring includes monitoring the allowable motor torque and the actual motor torque. The rationality judgment design of the motor direction for safety monitoring includes, by analyzing the torque and rotational speed direction of the P2 motor of the drive system and the direction of the gear lever, proposing a control strategy for rotational speed direction monitoring based on conditions such as the torque and rotational speed direction of the P2 motor, the direction of the gear lever, and the rotational speed change rate. The functional safety motor degradation design includes a method for judging the quality level of the motor torque based on the motor eddy current sensor, phase current sensor, motor temperature sensor, absolute value of the estimated motor torque, etc. The active discharge state monitoring of the motor includes a control strategy for monitoring the active discharge time of the motor. Introducing safety monitoring in the motor control strategy can prevent uncontrollable torque caused by failure and avoid dangerous states such as unexpected acceleration or unexpected deceleration of the entire vehicle.