مطالعات شبیه سازی در مرجع مبتنی بر روش کنترل تطبیقی ​​سرعت برآورد مدل برای بردار کنترل سنکرون آهنربای دائم درایو موتور

This paper presents a speed estimation technique for the permanent magnet synchronous motor drive. A Model Reference Adaptive System (MRAS) has been formed using the instantaneous and steady-state reactive powers to estimate the speed. It has been shown that such unique MRAS offers several desirable features. The proposed technique is completely independent of stator resistance and is less parameter sensitive, as the estimation-algorithm is only dependent on q-axis stator inductance. Also, the method requires less computational effort as the simplified expressions are used in the MRAS. The stability of the proposed system is achieved through Popov’s Hyperstability criteria. Extensive simulation results are presented to validate the proposed technique. The system is tested at different speeds including zero speed and a very satisfactory performance has been achieved.

Recently Permanent Magnet Synchronous Motor (PMSM) drives have received increased attention due to having several desirable features, such as, higher efficiency, higher power density, higher torque to inertia ratio etc. Vector controlled PMSM drive [1] has very high dynamic performance and are widely used in applications like machine tools, electric vehicles etc. Indirect vector controlled system requires the information of the speed: either from the speed encoder or from an estimator/observer [2], [3] and [4]. Elimination of the speed encoder is highly encouraged to increase the mechanical robustness of the system and to make the drive cheaper. Moreover, there are some applications, where there is no room to put the speed sensor or the nature of the environment (such as explosive environment in some chemical industries) does not allow the use of any additional speed sensor. This has made speed sensorless PMSM drive very attractive. Many speed estimation techniques have been reported in literature [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16] and [17]. They are broadly categorized as: 1.1. Back-emf based method [5] and [6] Use of back-emf to estimate the rotor speed has been reported [5] and [6]. This method offers satisfactory performance at higher speed. However, at zero or very low speed the back-emf becomes negligible. This makes the speed estimation at lower speed very difficult. Also, the method is highly sensitive to machine parameters.

A model reference adaptive controller based speed estimation technique has been presented. Reactive power is used as the functional candidate in the MRAS. The adaptation mechanism used the instantaneous reactive power in the reference model and the steady-state reactive power in the adjustable model. The use of steady-state reactive power eliminates the need of derivative computation. So, the method is less sensitive to noise. Also, the scheme does not need back-emf estimation and hence free from integrator related problems. This improves the performance of the estimator at very low and zero speed. Such unique formulation of MRAS makes the speed estimation algorithm independent of stator resistance (Rs), permanent-magnet-field-strength and d-axis inductance (Ld). The estimator is only dependent on q-axis inductance (Lq). As a consequence, on-line compensation of Lq makes the algorithm completely insensitive to parameter variation. The technique is very simple and utilizes simplified expressions in the reference and adjustable models, which in turn reduces the computation time to execute the algorithm in real time platform. No extra sensor or additional hardware is required for the realization of this technique. Therefore, the proposed method may also be used in retrofit applications.