Sensorless torque control of salient-pole synchronous motor at zero-speed operation

A position and speed sensorless control using the counter electromotive force of a permanent-magnet motor (PM) debases the control performance at a low speed. We propose a controllable system at full speed, including a zero speed using saliency. At low speed, the sensorless control is made by observing a current ripple at a time when alternating voltage has been applied to a salient-pole motor. Also, for discriminating the S and N poles of the magnet, magnetic saturation is used. A device has been applied to the motor rotor to allow the magnetic saturation to come about easily. Furthermore, at a time of high speed, drive at a full-speed range has been accomplished by switching smoothly over to a sensorless driving system making use of counter electromotive force. All algorithms are implemented by software, and this system can operate successively from starting to high-speed operation. The paper discusses the operational principles at a low speed, analysis and experimental results, the control scheme, how to changeover the control mode at high speed, and the experimental results.

[1]  A. Vandenput,et al.  Sensorless direct field orientation at zero flux frequency , 1996, IAS '96. Conference Record of the 1996 IEEE Industry Applications Conference Thirty-First IAS Annual Meeting.

[2]  Bimal K. Bose,et al.  Rotor position estimation scheme of a permanent magnet synchronous machine for high performance variable speed drive , 1992, Conference Record of the 1992 IEEE Industry Applications Society Annual Meeting.

[3]  Hiroshi Watanabe,et al.  DC-Brushless Servo System Without Rotor Position And Speed Sensor , 1987, Other Conferences.

[4]  M. J. Corley,et al.  Rotor position and velocity estimation for a permanent magnet synchronous machine at standstill and high speeds , 1996, IAS '96. Conference Record of the 1996 IEEE Industry Applications Conference Thirty-First IAS Annual Meeting.

[5]  J.H. Lang,et al.  Real-time observer-based (adaptive) control of a permanent-magnet synchronous motor without mechanical sensors , 1991, Conference Record of the 1991 IEEE Industry Applications Society Annual Meeting.