Parameter sensitivity of rotor time constant estimation based on MRAS for induction motors

Abstract

This paper analyzed parameter sensitivity of various model reference adaptive systems used in rotor time constant estimation in Indirect Field Oriented Control of induction motor. The simulation results of the parameter sensitivity shows the identification of rotor time constant are conducted by using MRAS, the coupling of three parameters exits and can not be avoided. In different conditions, the identification error is varied with different parameters. Thus merits and shortages are displayed in any single one way, and by combining them according to the varied situation is a better solution for the rotor time constant estimation.

Study on Model Reference Fuzzy Adaptive Control for Sensorless Vector Controlled Induction Motor Drives

“…Compared with the classical rotor flux based MRAS scheme (MRASF), stator current based MRAS Estimator (MRASCC) has a wider speed adjustment range [2]. Nevertheless, the MRASCC estimator is sensitive to the changes in the rotor time constant which vary during operation of the machine due to ohmic heating [4]. If rotor parameter error exists, it does not only change the achieved rotor speed, but it also changes the dynamic behavior of the whole field oriented control [5].…”

“…Thus, the performance suffers greatly in harsh and highly dynamic operating conditions, where the motor parameters are changing. Model reference adaptive system (MRAS) based observers, which is one of the best methods to estimate the rotor speed, are well-established sensorless techniques that have attracted much attention due to its performances and straight forward stability [2][3][4][5]. Compared with the classical rotor flux based MRAS scheme (MRASF), stator current based MRAS Estimator (MRASCC) has a wider speed adjustment range [2].…”

“…Therefore, the on-line rotor time constant estimation is inevitable to guarantee a competent performance in the IM drives. Several strategies have been proposed for rotor time constant estimation in the vector controlled IM drives [4,[6][7][8]. Among these techniques, MRAS based schemes are the most common strategies employed due to their relative simplicity and low computational effort [4,8].…”