PMSM drive using digital hall position sensors for light EV applications

The paper proposes a practical solution for a permanent magnet synchronous motor (PMSM) using digital Hall position sensors. An improved estimation method for the electrical angle is used, based on a speed estimate and a specific correction algorithm. The speed estimation is implemented in a “moving average” manner and is obtained at each Hall transition, for the last electrical period movement. This eliminates problems associated to Hall misalignment and misplacement, while still keeping a 60-degree upgrade rate for the estimation process. The position angle estimate is also gradually corrected based on the angle error detected at each Hall transition. A second phase correction, important at higher speeds, is used to compensate delays between Hall transition and the real-time interrupt control routine performing the vector control algorithm. Experimental results obtained on a 5kW (48V, 100Arms) three-phase, DSP controlled drive are presented and successfully validate the proposed solution.