SVM PMSM Drives with Low Resolution Hall-Effect Sensors

In this paper a back-EMF-based method is used in conjunction with three very low-cost integrated circuits based on the Hall-effect to estimate the rotor position of the direct-drive PMSMs to be used for traction purpose of an electric wheelchair. A speed estimator based on rotor frame machine model (SERF) has been implemented for the PMSM drives, and then the rotor position estimation is achieved by means of a discrete integration of the estimated speed. The three Hall effect sensors are used to detect the rotor initial position as well to reset the error on the rotor position estimation every 60 electrical degrees. In the specific application, SVM technique has been implemented together with the field oriented control. Simulations and experimental results are shown in the paper