Control Strategy For Induction Machine Research Articles

Advanced speed sensorless control strategy for induction machine based on neuro-MRAS observer

High-performance field-oriented motor control requires accurate knowledge of flux and speed information. Furthermore, the elimination of sensors leads to reduced overall cost and size of the electric drive system and subsequently improving its reliability. So far, Speed sensorless control of induction motors has been faced with various techniques of speed estimation. However, the main drawbacks of these models are their insufficient performance at low speeds, along with sensitivity to parameters variation, which engenders an unsteady drive system. This paper proposes an effective sensorless indirect Field Oriented control scheme for an induction motor drive. The proposed speed observer combines artificial intelligence and model reference adaptive system (MRAS). This observer is associated with the control scheme as sensorless algorithms for rotor speed and flux estimation. This conjunction is intended to enhance the conventional MRAS performance especially in low-speed regions and reduce its sensitivity to noise and system uncertainties as well. Otherwise, the effectiveness of the proposed speed estimator is tested in simulation using Matlab/Simulink software environment. The control structure is checked in the low speed with load variation.

An optimized vector control strategy for induction machines during open‐phase failure condition using particle swarm optimization algorithm

Background 3ϕ Induction Machine (IM) drives are broadly used in different industrial applications. During failure conditions, 3ϕ IM drive systems cannot continue its optimal performance. Aims The present study presents a method for indirect rotor field-orientated control (IRFOC) of star-connected 3ϕ IM drives during open-phase failure (OPF) condition. In addition, in this study the particle swarm optimization algorithm was used to determine the coefficients of proportional-integral (PI) controllers in the OPF mode. Materials & Methods In the proposed method, two unbalanced currents and voltage rotational matrices are utilized to change the asymmetrical structure of the faulty 3ϕ IM equations to the equations with a symmetrical structure. Using these matrices, the speed control of the faulty 3ϕ IM can be realized with minor changes in the conventional IRFOC structure including control parameters, transformation matrices, and coefficients of PI controllers. Results Experimental results were presented during various operating conditions on a 1 HP star-connected 3ϕ IM drive system. Discussion The experimental tests in different operating conditions showed good performances of the proposed control system during both the steady-state and the transient periods. Conclusion The proposed control method exhibited a significant improvement in reducing the speed, torque, and flux oscillations, compared to the standard IRFOC system during OPF. In addition, the results obtained from the comparison between the proposed vector control method with and without the optimized coefficients of PI controllers indicated the effect of the optimization of PI controllers in the proposed IRFOC system for the 3ϕ IM drive during OPF.

Novel DTC induction machine drive improvement using controlled rectifier for DC voltage tuning

<span lang="EN-US">The application of the direct torque control strategy for induction machine drives is mainly characterized by torque and flux distortions caused by voltage vector limitation. The goal of this paper is to perform the conventional DTC induction machine drives and reduce ripples of both flux and torque response. The proposed contribution is based on the control of the DC output side of the rectifier feeding the voltage source inverter by means of PI controller in order to adapt the voltage vector used in typical DTC switching table. Mathematic models are built using MATLAB Simulink and programming environment; the simulation results show the difference between the proposed method and classical DTC.</span>

Field oriented predictive control strategy for induction machine drives

PurposeThis study aims to drive the induction machine system with a low switching frequency.Design/methodology/approachAn unconventional inverter control strategy – field-oriented predictive control (FOPC) – is presented. The strategy limits current distortion by setting a boundary circle. The voltage vector, which could keep current trajectories in boundary, is selected to obtain a low switching frequency.FindingsA dual simulation step technique is developed to investigate the influence of sampling frequency on current distortion control and switching frequency. Current control distortion can be improved, i.e. reduced, by increasing the sampling frequency; however, the switching frequency will also increase. Such a law is discovered by the dual simulation step technique and finally verified by experiments.Originality/valueA new predictive control method, FOPC, is derived from the rotor filed coordinate machine model and presented in this paper. FOPC circumvents derivative calculations, and thus avoids high-frequency noise amplification.

Commande vectorielle d'un moteur asynchrone sans capteur

A field-oriented control strategy for induction machines which does not use mechanical sensors is presented. The rotor flux is observed by a reduced-order Luenberger-type observer based on a model using a stator-fixed reference frame. An estimate of the rotation speed is derived from the flux vector, the measured stator currents and the field orientation angle. Simulations demonstrate that this control strategy performs well even in the presence of parameter variations up to ±50% (resistances)