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This paper presents a novel approach of speed control for a permanent magnet synchronous motor (PMSM) using on-line self tuning artificial neural network (ANN). Based on motor dynamics and non-linear load characteristics, an ANN speed controller is developed and integrated with the vector control scheme of the PMSM drive. The combined use of off-line and on-line weights and biases adjustments offers a unique feature of on-line system identification and precise speed control of a high performance PMSM drive. The complete drive system is implemented in real time using a digital signal processor controller board-DS1102 on a laboratory 1 hp PMSM. using the experimental setup, the performances of the proposed drive system are evaluated under various operating conditions. The test results validate the efficacy of the ANN for precise speed control of the PMSM drive. Furthermore, the use of ANN makes the drive system robust, accurate and insensitive to parameter variations. Keywords - Artificial Neural Network, Permanent Magnet Synchronous Motor, On-line System Identification, Hysteresis Current Controller, Speed Control

A method to analyze the steady-state performance of a stand-alone permanent magnet synchronous generator driven by a diesel engine is presented. The proposed method is based on the equivalent d-q circuits and phasor diagram of such a generator in steady-state condition. A fixed capacitor-thyristor controlled reactor scheme is used to regulate the generator terminal voltage by controlling the thyristor ignition angle. Furthermore the overall system dynamics are modelled in terms of state variables and control inputs. Based on a reduced order linearized model, digital optimal state and output feedback controllers are designed by minimising a quadratic performance index using the dynamic programming technique. The objective of the controller is to maintain the load voltage and frequency constant under varying load conditions. The controller's effectiveness is assessed by examining the closed-loop system response to sudden load changes. Keywords: Permanent magnet synchronous generators, optimal control, static VAR compensator.

Several types of ac bearingless motors are proposed. These bearingless motors have conventional four-pole stator windings and additional two- pole windings, whose currents produce radial forces acting on the rotor. General expressions of the machine inductances and radial forces are derived for the cylindrical rotor and salient-pole motors. No-load characteristics of laboratory squirrel-cage induction and reluctance-type synchronous bearingless motors are provided. The test motors were successfully driven by the control circuits.

In this paper, an on-line adaptive loss minimization controller (ALMC) for interior permanent magnet motor drives is introduced after the minimum loss operation of these motors is analyzed. The ALMC provides a novel pattern of change in d-axis stator current to achieve a minimum drive input power at any operating condition. The operation of the ALMC results in a smooth and fast loss minimization, thus overcoming the major drawbacks of existing on-line loss minimization control approaches. The proposed ALMC provides more energy savings in comparison with other methods and extends the application of loss minimization control to a class of motor drives requiring efficient and smooth operation in the face of frequent changes in the operating point. The design and DSP implementation of the ALMC applied to an experimental 1 hp rare-earth IPM motor drive are presented. Several experimental results are given to prove the validity of the ALMC. Keywords: Loss minimization control, Efficiency optimization, Permanent magnet motors, On-line control, Adaptive controller.

For most surface mounted permanent magnet synchronous motors, the electrical time constant is relatively small due to its large air gap. This has been exploited recently with small parameter perturbation techniques to develop observers for the position and speed using measurements of currents. In this paper, a singular perturbation algorithm is experimentally evaluated for both current commutation and closed loop speed control of a permanent magnet synchronous motor drive. An improved algorithm is then proposed and related implementation issues are presented. Keywords: sensorless control, observer, singular perturbation, speed control, PMSM drive