Pavol Makys

Position Estimation of AC Machines Over a Wide Frequency Range Based on Space Vector PWM Excitation

This paper presents a new method for position estimation in shaft-sensorless ac motor drives over the entire speed range, including zero frequency. The method is based on the standard fundamental wave space vector pulsewidth-modulation (PWM) excitation sequence and requires neither an observer-based model nor a signal injection test signal. Experimental results confirm the effectiveness of the new technique, and a comparison with other PWM-excitation-based methods for estimating the rotor position of ac machines is made.

Comparison of sliding mode and forced dynamics control of electric drive with a flexible coupling employing PMSM

The paper presents comparison of two control techniques (a) sliding mode and (b) forced dynamics for control of electric drives employing permanent magnet synchronous motors with flexible coupling. The designed controllers are of the cascade structure, comprising an inner speed control loop and an outer position control loop. The inner speed control loop for both controllers is based on forced dynamics and respects the principles of vector control. The outer position control loops are designed to control load mass angle in the presence of a vibration mode with an external load torque. Derived control laws requires estimates of the load torque and the second one also its derivatives, which are estimated in the especially designed load torque observer. The simulations presented indicate that the control systems operate according to theory and therefore further investigations including experimental implementation are recommended.

Forced dynamics control of PMSM drives with torsion oscillations

Purpose – The purpose of this paper is to discuss the design and verification of a new control algorithm for the drive with permanent magnet synchronous motor (PMSM) and flexible coupling based on “Forced dynamics control”. Control laws are derived and tested for the rotor and load angle control and achieve non‐oscillatory position step response with a specified settling time.Design/methodology/approach – “Forced dynamics control” is a new control technique based on feedback linearization which forces rotor or load position to follow demanded position with prescribed closed‐loop dynamics. The proposed control structure is developed in two steps: first, the feedback linearisation is applied to the rotor speed and then similar technique is used for position control loop.Findings – The proposed controller is of the cascade structure, comprising an inner speed control loop, respecting vector control principles and outer position control loop designed to control the rotor or load angle, respectively. Estimates...

Sensorless Control of Induction Machines, including Zero Frequency using only Fundamental PWM Excitation

This paper reports the implementation of a sensorless control scheme for AC machines that requires neither a model observer nor a test-signal. The model is based on saliency detection through the use of fundamental PWM excitation and the measurement of the derivatives of the line currents induced by the PWM voltage vectors. Derivation of the rotor position is possible at low and zero speeds without separate test signals and also at higher speed without the knowledge of the machines model. Experimental results showing fully sensorless induction motor control at low and higher speeds validate the principle of this method

Optimization of switched reluctance motor design procedure for electrical vehicles

This paper deals with optimization process of switched reluctance motor (SRM) during design procedure. This optimization process uses finite element method (FEM) to improve motor performances and properties. On the base of four phase 8/6 SRM analytical design given by known equations and formulas, some improvements and materials utilization are obtained by optimization process. This optimization design procedure is described in details. The static and dynamic parameters and waveforms are calculated and compared for both of motors. The output characteristics as torque and power versus speed are given and compared for electrical vehicle application.

Chattering free sliding mode control law for the drive employing PMSM position control

The control system for position control of the drive employing PMSM based on the principles of sliding mode control and respecting the principles of vector control is presented. Designed controller is chattering free and complies with demanded control precision. Described control technique divides PMSM into two channels, which enable to control motor flux and torque separately. The controller is of the parallel structure, comprising a control loop for control of machine magnetic flux and parallel loop for control of the machine torque and rotor angle. To achieve demanded precision and to eliminate control chattering a smoothing integrator is introduced into both parallel controllers and furthermore the signnm function is replaced by a proportional high gain in the final version of the controllers. The simulations and preliminary experimental results indicate that the control systems yield the desired robustness and more complex investigations are recommended.

Static and dynamic fault analysis of Switched Reluctance Motor

This paper deals with static and dynamic analysis of the Switched Reluctance Motor (SRM) under fault operating conditions. The static analysis is carried out by means of Finite Element Method (FEM) to investigate static parameters of the SRM for health and some defined faults of the phases. These static parameters are used in the dynamic model of the SRM and some transients are simulated for normal condition and also for fault operation. The comparison with experimental results is presented.

Energy Near-Optimal Control Strategies for Industrial and Traction Drives with a.c. Motors

The main contribution of this paper is a new rest-to-rest position control system for use with electric drives employing a.c. motors that is near-optimal with respect to combined electrical and frictional energy waste minimization. The friction has constant, linear, and quadratic components with respect to the rotor speed. The closeness to optimality is assessed by simulation, comparing the energy loss of the new control system with that predicted by computed optimal controls. The application of the near-optimal control system is rendered straightforward by using a symmetrical trapezoidal speed-time profile. This is provided by an energy saving reference position generator whose output is faithfully followed by means of a feedback control law based on forced dynamics control yielding prescribed closed loop dynamics, together with a matched zero dynamic lag precompensator. For load torque consisting of constant, linear, and quadratic components also maneuver time is optimized if it can be chosen arbitrary. Two case studies, one applied to position control of rotational drive and second one applied to train movement, confirm the possibilities of achieving energy savings.

Design of fault tolerant control technique for SRM drive

This paper deals with the improvement of the switched reluctance motors fault tolerant control for traction drives. The main purpose is to use a control technique which is able to retain the required speed for various load torques at minimal torque ripple also during one opened phase operation. The paper focuses on the comparative study of the current hysteresis control and direct instantaneous torque control (DITC) techniques.

A novel design conception of Switched Reluctance Motor for electrical vehicles

This paper deals with a novel design conception of Switched Reluctance Motor (SRM) for electrical vehicles as electrical mini truck. This design consists of segmented stator with toroid windings water cooled and the rotor has salient poles. The SRM dimensions are calculated on the base of input requirements. The static and dynamic parameters of SRM are obtained from simulation models based on Finite element method and torque, power versus speed characteristics are presented.