Abstract
The position information is very important when driving the synchronous motor in the integrated starter and generator (ISG) drive system of the 48V mild hybrid electric vehicle. In order to reduce the cost of the ISG drive system, the hall sensing method which has the hall sensor IC in the control board of the inverter and the sensor magnet in the shaft of the motor is applied. However, in the case of the claw-pole motor, the flux generated by the sensor magnet is seriously deteriorated due to the flux generated by the field current of the rotor. So this disturbance generates the periodic position errors in the electrical rotor angle. When the vector control with periodic position error is done, the torque ripple and dc-link voltage/current ripples are generated and also the dynamic tracking performance is limited by inaccurate position information. Thus in this paper, the position sensing error mitigation method based on the PLL (Phase Locked Loop) algorithm is presented. The rotor position angle from the hall sensor IC has a dominant ripple component which occurred from the relationship between the mechanical angle and the electrical angle. Thus, the proportional-integral (PI) controller and the feed-forward reference speed in the PLL algorithm are designed by considering this relationship. The simulation results show the reduced speed error and the reduced harmonics in the stator current. In the final paper, the simulation and experimental results will be presented along with the detailed explanation and discussion.
KEYWORDS : Hall Sensor, PLL, ISG