Sensorless Vector Control of Induction Motor Stabilized at the Whole Region with Speed and Stator Resistance Identification based on Augmented Error

Abstract

This paper proposes new identification laws of an adaptive flux observer for speed sensorless vector controls. In speed sensorless vector controls of an induction motor with the adaptive observer, the speed identification system is known to be unstable in a part of regenerating region. In addition, it is pointed out that the stator resistance variation interferes with the speed identification. Thus it is necessary to find an adaptive scheme which can stabilize the identification system.In this paper, firstly, the stability on the parameter identification is discussed from the viewpoint of Popov's hyper stability. Secondly, identification laws for the speed and the stator resistance are proposed based on the new identification system which is derived by using the augmented error. Finally, effectiveness of the proposed method is shown by experiments.

Sensorless Vector Control of Induction Motors Using Minimum Dimensional Flux D‐State Observer with Instantaneous Speed Estimation

“…A typical approach to rotor flux estimation is the configuration of a flux state observer. State observer-based vector control methods using this approach can be divided into two groups: those with full-order (fourth order) flux state observers [1][2][3][4][5][6][7] and those with minimum-order (second order) flux state observers [8][9][10][11][12][13]. In the latter case, as compared to the former, the design of the observer gain, which governs observer performance, is easier, and the computing load is reduced by about half.…”

“…In IM vector control not using encoders or other position/speed sensors, the speed must be estimated, in addition to the flux phase. When a full-order flux state observer is employed, the observer is adapted on the basis of adaptive state observer theory so that the rotor speed can be adaptively identified [1][2][3][4][5][6][7]. The additional computing load needed for this purpose is usually small.…”

Performance improvement of induction motor speed sensor‐less vector control system using an adaptive observer with an estimated flux feedback in low‐speed range

“…Many speed estimation methods have been proposed and some have been put into practical use [1][2][3]. Methods of improving the estimation performance include, for example, identification of the primary and secondary resistances [4][5][6][7], optimum design of an observer [8], and high-frequency signal injection [9]. Conventional studies have also pointed out that in addition to optimization of the speed estimation method, it is also important to reduce the errors of the motor parameters, especially the primary resistance error at low speed, and that both speed estimation and primary resistance identification are apt to become unstable in regenerative operation [10,11].…”

Experimental verification for stability improvement of sensorless vector control system of induction motor using real‐time tuning of observer gain

“…The system becomes unstable at low speed and in regenerating mode. To enhance the low speed performance, adaptive gain design for the Adaptive Rotor Flux Observer (AFO) has been proposed [3,4] and a method of correction of the adaptive law has been proposed [5,6]. Stability improvements for low speed and regenerating operation are reported in each approach.…”

“…Both design methods assure stability at low speed and in regenerating operation except for a small region near zero frequency. Hamajima proposed a rotor speed and stator resistance identification method based on augmented error [5]. Hinkkanen proposed a rotor speed identification method based on the current estimation error component which is parallel to the rotor flux estimate [6].…”