A Novel Micro Permanent Magnet Synchronous Motor Drive System without using a Rotor Position

This paper proposes a novel shaft position/speed estimating technique for a micro permanent magnet synchronous motor. By using the special characteristics of the micro motor, the back emf of the motor can be easily detected. In addition, the shaft position/speed can be derived according to the back emf. After obtaining the rotor position and speed, a closed-loop drive system can be achieved. A TMS-320-LF2407A DSP is used to estimate the shaft position/speed. In addition, a current controlled circuit, PWM circuit, and an inverter are implemented to control the stator current, and then control the motor. As a result, a closed-loop system is thus achieved. Experimental results validate the theoretical analysis