Observer-based estimation improvement for servo control of PMSM with binary-type hall sensors

Permanent magnet synchronous motor (PMSM) driving system with vector control scheme requires rotor position information. The Hall-effect position sensors are used for achieving a moderate control performance, compared with sensorless control, a better control ability can be obtained, and it is in smaller volume and more cost-effective compared with other types of position sensors. Position estimation strategies based on observer feature ideal continuity and good dynamic characteristics. However, the observer estimated state may diverge when mechanical or electrical parameters uncertainties occur, also bumps exist between two hall intervals when discretization is not suitable. To solve these issues, a new observer structure combined with the reduced-order observer and multi-sampling method is proposed, it can fully use the real information from hall sensors and achieve a bumpless speed estimation as well as parameter robustness. Performance of the proposed algorithm is validated through simulations and implementation on a low cost servo platform.