Adaptive Compensation Algorithm for Flux Estimation of PM BLDC Motor Drives

摘要

The low-cost low-power Hybrid Electric Vehicle uses PM BLDC motor without shaft encoder. Therefore, the speed estimation has to be carried out through accurate estimation of flux and its angle. The adaptive magnitude compensation suggested for sinusoidal systems as a substitute for normal integration, works well for even non-sinusoidal emf of PM BLDC motor. The selection of cut-off frequency and tuning of PID has to be done in a manner to meet the wide speed range requirements. At lower speed PID tuning needs to be done optimally. However, the flux estimation can be carried out accurately up to speed down to 1 rad/s. The simulation has been run for 100 rad/s motor speed and at 10 Nm load torque. Results show the elimination of DC drift in the estimated stator flux.