Traction Motor
The traction motor is a 3-phase permanent magnet AC motor connected to the ring gear of the planetary gear set. The traction motor is connected to the drive wheels through a series of gears and rotates whenever the drive wheels rotate. The traction motor power inverter (internal to the transaxle) receives a DC current from the high voltage traction battery. The DC current is inverted to an AC current, which is controlled by the transaxle control module (TCM) and the motor control unit (MCU). The traction motor can deliver positive torque by propelling the vehicle in the forward or reverse direction. It can also provide negative torque by functioning as a generator during the regenerative braking. The TCM receives input from the position sensor as well as the motor coil temperature sensor. The TCM monitors the motor coil temperature and sets a diagnostic trouble code (DTC) if the temperature exceeds a maximum threshold value. The TCM also monitors motor position, speed, phase current, power inverter temperature, and voltage. The TCM processes a variety of the powertrain control module (PCM) and the traction battery control module (TBCM) inputs to determine motor function. The inputs are divided into 2 categories: the hardwired signals and the network messages. The inputs used to determine motor function include the total torque desired, the motor inverter shutdown, and the vehicle mode. The traction motor is used to provide torque to the axle shafts and recharge the high voltage traction battery during the regenerative braking. The TCM reports the motor error status to the PCM. The PCM initiates an appropriate LOS mode and sets the DTC P1A0E (Hybrid powertrain control module - traction motor disabled) based on the error status received. The TCM also sets a DTC which indicates why the traction motor malfunctioned.