An Improved Position and Speed Estimation Scheme for Permanent Magnet Synchronous Motor with Low-cost Hall Sensors

Permanent magnet synchronous motor (PMSM) with Hall sensors has been widely used in the industrial electronic vehicle fields with the requirements of low cost, small volume and high performance in full speed region. Compared with sensorless control, the Hall sensor is the guarantee of low cost and control performance. However, the low-resolution Hall sensors deteriorate the accuracy of position and speed calculation in vector control scheme. Thus, an improved method for position and speed estimation is proposed in this paper. The proposed method combines the non-model-based least square algorithm (LSA) and the model-based sliding mode observer (SMO) to estimate position and speed effectively. Meanwhile, the load torque is estimated as a feedforward quantity of current loop to improve the anti-interference performance. Compared with the traditional average speed method, the proposed combined estimation method has superior performance. The effectiveness and feasibility of the proposed method is verified by the simulation results.