A Universal Gains Selection Method for Speed Observers of Induction Machine

Daniel Wachowiak

doi:10.3390/en14206790

Abstract

Properties of state observers depend on proper gains selection. Each method of state estimation may require the implementation of specific techniques of finding those gains. The aim of this study is to propose a universal method of automatic gains selection and perform its verification on an induction machine speed observer. The method utilizes a genetic algorithm with fitness function which is directly based on the impulse response of the observer. System identification using least-squares estimation is implemented to determine the dynamic properties of the observer based on the estimation error signal. The influence of sampling time as well as signal length on the system identification has been studied. The results of gains selection using the proposed method have been compared with results obtained using the approach based on the placement of the poles of linearized estimation error equations. The introduced method delivers results comparable with analytical methods and does not require prior preparation specific to the implemented speed observer, such as linearization.

Highlights

The availability and low price of microcontrollers and digital signal processors caused the rapid development of controlled electric drives [1,2,3,4]
After those parameters are determined, the possibility of implementation of fitness function based on this method is verified using the genetic algorithm to find observer gains
The studies presented in this study confirm that the proposed method can be successfully applied to find gains of the speed observer

Summary

Introduction

The availability and low price of microcontrollers and digital signal processors caused the rapid development of controlled electric drives [1,2,3,4]. Most of the advanced induction machine control systems require knowledge of hard to measure variables such as rotor flux. In practice such measurement is avoided, and state estimation is performed instead [7,8]. Rotor speed is another variable that does not have to be directly measured, equipment for speed measurement is widely available, as sensorless drives gain popularity

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Results

Conclusion