Developments in Sensorless AC Drive Technology

Controlled AC motor drives without mechanical speed sensors at the motor shaft have the attractions of low cost and high reliability. To replace the sensor, the information on the rotor speed is extracted from measured stator currents and from the voltages at the motor terminals. Vector controlled drives require estimating the magnitude and spatial orientation of the fundamental magnetic flux waves in the stator or in the rotor. Open loop estimators or closed loop observers are used for this purpose. They differ with respect to accuracy, robustness, and sensitivity against model parameter variations. Dynamic performance and steady-state speed accuracy around zero speed range is achieved by signal injection, exploiting the anisotropic properties of the machine. The overview in this paper uses signal flow graphs of complex space vector quantities to provide an insightful description of the systems used in sensorless control of AC motors

[1]  Joachim Holtz,et al.  The representation of AC machine dynamics by complex signal flow graphs , 1995, IEEE Trans. Ind. Electron..

[2]  M. Schroedl,et al.  Sensorless control of AC machines at low speed and standstill based on the "INFORM" method , 1996, IAS '96. Conference Record of the 1996 IEEE Industry Applications Conference Thirty-First IAS Annual Meeting.

[3]  Robert D. Lorenz,et al.  Using multiple saliencies for the estimation of flux, position, and velocity in AC machines , 1997 .

[4]  Joachim Holtz,et al.  Vector-controlled induction motor drive with a self-commissioning scheme , 1991 .

[5]  Frede Blaabjerg,et al.  Very low speed sensorless variable structure control of induction machine drives without signal injection , 2003, IEEE International Electric Machines and Drives Conference, 2003. IEMDC'03..

[6]  J. Holtz,et al.  Elimination of saturation effects in sensorless position controlled induction motors , 2002, Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344).

[7]  Joachim Holtz,et al.  On the spatial propagation of transient magnetic fields in AC machines , 1995 .

[8]  Joachim Holtz,et al.  Acquisition of rotor anisotropy signals in sensorless position control systems , 2003 .

[9]  J. Holtz,et al.  Drift and parameter compensated flux estimator for persistent zero stator frequency operation of sensorless controlled induction motors , 2002, Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344).

[10]  Ralph Kennel,et al.  Sensorless position control of permanent magnet synchronous machines without limitation at zero speed , 2002, IEEE 2002 28th Annual Conference of the Industrial Electronics Society. IECON 02.

[11]  Yoshihiro Murai,et al.  Waveform Distortion and Correction Circuit for PWM Inverters with Switching Lag-Times , 1987, IEEE Transactions on Industry Applications.

[12]  Joachim Holtz.  Sensorless position control of induction motors-an emerging technology , 1998, IECON '98. Proceedings of the 24th Annual Conference of the IEEE Industrial Electronics Society (Cat. No.98CH36200).

[13]  J. Holtz,et al.  Sensorless vector control of induction motors at very low speed using a nonlinear inverter model and parameter identification , 2001, Conference Record of the 2001 IEEE Industry Applications Conference. 36th IAS Annual Meeting (Cat. No.01CH37248).

[14]  Joachim Holtz,et al.  Sensorless control of induction motor drives , 2002, Proc. IEEE.

[15]  K. Matsuse,et al.  Speed sensorless field oriented control of induction motor with rotor resistance adaptation , 1993, Conference Record of the 1993 IEEE Industry Applications Conference Twenty-Eighth IAS Annual Meeting.