Stator Field Orientation Research Articles

Sensorless torque and flux control of induction motor fed by photovoltaic system

This paper presents a new direct torque and flux control method for induction motor fed from Photovoltaic (PV) System. The proposed strategy is based on Stator Field Orientation with deadbeat torque and flux control. The deedbeat control approach is based on establishing the voltage vector necessary to supply the motor and reach the electromagnetic torque and flux references at the end of a sampling period T. In order to create the voltage shape and frequency to control the induction motor, the inverter is supplied by a DC voltage extracted from a PV system. Model Reference Adaptive System and Luenberger Observer are designed to determine the stator flux and rotor speed. Extensive simulation work was carried out, which demonstrated that the proposed strategy is capable of reducing the torque and flux ripples and maintaining a constant switching frequency.

Speed Estimation of Stator Field Orientation Control Induction Motor Drive Based on the Particle Swarm Optimization Algorithm

Speed Estimation of Stator Field Orientation Control Induction Motor Drive Based on the Particle Swarm Optimization Algorithm

Comparative Analysis of the Doubly Fed Induction Generator (DFIG) Under Balanced Voltage Sag Using a Deadbeat Controller

This paper shows a Deadbeat controller for a wind generator during a balanced voltage sag condition. The control is made with a Stator Field Oriented Control technique using the DSOGI-QSG applied on the estimation of positive sequence of stator voltage vector and the stator current vector. The control strategy used is fully explained, and then it is tested using Matlab/Simulink, considering two scenarios: for the first one, the generator must be forced to generate reactive power and maintain the active power in zero, during voltage sag condition according with the new network requirements. For the second test, the generator must maintain rotor currents within safe levels to prevent damages for the windings during voltage sag. Simulation results and conclusions about controller perfomance during the voltage sag condition are presented.

Stator Field-Orientation Speed Control for 3-Phase Induction Motor under Open-Phase Fault

The industrial requirements for the control of an induction motor (IM) under fault conditions continue to be of attention, as evidenced by the majority current publications. The focus is on developments of control methods which can be used for faulty IM. A novel vector control technique based on stator field-oriented control (SFOC) for a 3-phase IM under open-phase fault is proposed in this paper. MATLAB simulation results are presented to illustrate the improvement in performance of the proposed algorithm. It has shown that for providing an appropriate algorithm to control faulty machine with one opened phase, the modification in the conventional controller is possible.

The Control System for Three-Phase Induction Motors Based on Stator Flux Orientation

In this paper, the mathematical model of induction motor based on stator field orientation in synchronous frame is introduced. To resolve the question of relay, the d-axis current direct calculation is adopted to replace traditional decoupler. Fix threshold double-integrator based on coordinate transformation is used to eliminate integrator saturation. SVPWM based on 600 coordinate system is developed to simplify calculation. The control system based on stator flux orientation is simulated by MATLAB. The simulation result shows that the system has a fast dynamic response and steady characteristics.Nomenclature

Adaptive Speed Observer for a Stand-Alone Doubly Fed Induction Generator Feeding Nonlinear and Unbalanced Loads

In this paper, an improved sensorless control algorithm for a variable speed constant frequency doubly fed induction generator is presented. Unlike previously reported methods the proposed algorithm does not require the rotor position or speed information for the stator field orientation of the rotor variables. The slip frequency is estimated by a reactive power-based model reference adaptive observer and is used in the rotor current controllers for back emf compensation. A new on-line estimation method for the magnetizing inductance of the machine is also proposed to enhance the performance of the controller. Small-signal models of the slip frequency and the magnetizing inductance estimators are developed to aid their design. The proposed algorithm is capable of “speed catching on the fly” and performs satisfactorily with balanced, unbalanced, linear, and nonlinear loads (in any combination) particularly, nonlinear unbalanced loads, which has not been reported in the literature so far. Experimental and simulation results are presented to demonstrate an excellent load voltage regulation property of the control algorithm during severe transient operating conditions. Total harmonic distortion and unbalance of the load voltage and stator current even with large nonlinear/unbalanced loads are also found to be much smaller compared to systems reported earlier.

Sensorless stator field orientation controlled induction motor drive with a fuzzy speed controller

A sensorless stator-field oriented control induction motor drive with a fuzzy logic speed controller is presented. First, a current-and-voltage parallel-model stator-flux estimator is established using measured phase currents and voltages of the induction motor. Then the estimated rotor shaft position is obtained from the magnitude and position of the estimated stator flux. The speed controller is developed by utilizing fuzzy logic control techniques. The control algorithms are realized by a DSP 6713 and, using a DSP F2812 to generate PWM signals to the power stage, drive the motor to experimentally validate the proposed approach.

A Deadbeat Controller for Doubly-Fed Induction Generator Power Control

A deadbeat power control scheme for doubly-fed induction generator for variable speed was proposed. The deadbeat controller algorithm calculates the voltage vector to be supplied to the rotor in order to eliminate the active and reactive power errors in each period using and stator field orientation and the doublyfed induction generator dynamic model. The deadbeat controller uses the rotor current control to the power control of the machine. This control technique can be applied to the wind energy systems. Experimental results are carried out to validate of the deadbeat controller operation.

Sensorless Indirect Stator Field Orientation Speed Control for Single-Phase Induction Motor Drive

The industrial requirements for the control of an induction machine without a mechanical sensor continue to be of interest, as evidenced by the most recent publications. The focus is on improvements of control without a mechanical sensor. A new method for the implementation of a sensorless indirect stator-flux-oriented control (ISFOC) of a single-phase induction motor (SPIM) drive is proposed in this paper. The proposed method of rotor speed estimation is based only on the measurement of the main and auxiliary windings stator currents and that of a reference <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">q</i> -axis current generated by the control algorithm. The error of the measured <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">q</i> -axis current from its reference value feeds the proportional plus integral controller, the output of which is the estimated slip angular frequency. Experimental results for sensorless ISFOC speed control of a SPIM drive are presented and analyzed using a dSPACE system with DS1104 controller board based on the digital signal processor TMS320F240. Digital simulation and experimental results are presented to show the improvement in performance of the proposed sensorless algorithm.

Observer-based direct field orientation: analysis and comparison of alternative methods

This paper focuses on methods of achieving direct field orientation (DFO) of induction machines based on closed-loop, stator, and rotor flux observers which are well suited to both zero and very high-speed operation. Both observer topologies are dominated by a current model at zero and low speeds, and a voltage model at high speeds. Application of such rotor and stator flux observers to both stator and rotor direct field orientation is presented, including experimental results for three different methods. The influence which flux regulation has on parameter sensitivity of the complete DFO system is analyzed. A rotor-flux-regulated and -oriented system is shown to be sensitive to leakage inductance under high slip (i.e., field weakened) operation. Both a stator-flux-regulated and -oriented system and a stator-flux-regulated, rotor-flux-oriented system are shown to have reduced parameter sensitivity at high speeds. Unlike stator flux orientation using simple voltage integration stator flux models, excellent zero and low-speed operation of an observer-based stator-flux-oriented system is demonstrated.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>