Position control of a sensorless interior permanent magnet synchronous motor system

This paper proposes a novel sensorless position control system for an interior permanent magnet synchronous motor. In this paper, a novel rotor position estimation technique is proposed. This estimation technique only relates to the slopes of the three-phase stator currents, and does not relate to the parameters or operating conditions of the motor. Neither extra circuit nor external exciting signal is required here as compared with the traditional drive system with an encoder feedback. In addition, the proposed rotor position estimator works well in transient, steady state, and standstill conditions. The proposed system performs well in both adjustable speed control and position control. A digital signal processor, TMS-320-LF-2407 is used to execute the rotor position estimation, the current-loop control, the velocity-loop control, and the position-loop control. As a result, a fully digital control system is achieved. Several experimental results validate the theoretical analysis