Sensorless Field-oriented Control Research Articles

Adaptive pseudoreduced-order flux observer for speed sensorless field-oriented control of IM

An adaptive pseudoreduced-order flux observer for speed sensorless field-oriented control is presented. In comparison with the adaptive full-order flux observer, the proposed method consumes less computational time and illustrates better speed performance. Simulations and experiments on a 3-hp induction motor verify the validity of the proposed method.

Sensorless field orientation control of induction machines based on a mutual MRAS scheme

A mutual model reference adaptive system (MRAS) is proposed to implement a position sensorless field-orientation control (FOC) of an induction machine. The reference model and adjustable model used in the mutual MRAS scheme are interchangeable. Therefore, it can be used to identify both rotor speed and the stator resistance of an induction machine. For the rotor speed estimation, one model is used as a reference model and another is the adjustable model. Pure integration and stator leakage inductance are removed from the reference model, resulting in robust performance in low and high speed ranges. For the stator resistance identification, the two models switch their roles. To further improve estimation accuracy of the rotor speed and stator resistance, a simple on-line rotor time constant identification is included. Computer simulations and experimental results are given to show its effectiveness.

Current sensorless field-oriented control of induction motors

A new method for controlling a current sensorless induction motor is presented. It uses a partial state estimator to estimate the torque-current and a voltage predictor to predict the voltage vector of voltage source inverter (VSI). In the system, a speed controller, a torque-current estimator, a voltage-predictive voltage-source inverter (VPVSI) and a slip calculator are included. Fast response and adaptive field weakening above the base speed of the induction motor are achieved through a direct software control system based on field orientation with recursive operation between partial state estimation and voltage prediction. Besides low cost, the simplicity of the system hardware yields high reliability and good maintainability.

Speed sensorless field-oriented control of induction motor with rotor resistance adaptation

Several field-oriented induction motor drive methods without rotational transducers have been proposed. These methods have a disadvantage that the rotor resistance variation causes an estimation error of the motor speed. Therefore, simultaneous estimation of the motor speed and the rotor resistance is required. This paper presents a method of estimating simultaneously the motor speed and the rotor resistance of an induction motor by superimposing AC components on the field current command. The validity of the proposed method is verified by simulation and experimentation. >

Speed sensorless field-orientation control of the induction machine

A speed estimation method for an induction machine and its application to a flux observer-based field orientation (FOFO) control system proposed previously is presented. The motor speed is estimated on the basis of the difference between two flux estimators. The convergence of the method is analyzed, and a novel pole assignment method is proposed. The speed estimator is applied to the FOFO controller. The system has been implemented using a DSP, and some laboratory experiments showing that the speed-sensorless FOFO operates with enough stability and has a strong robustness to rotor resistance variation are reported.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>