Murat Karabacak

Sensorless control application of PMSM with a novel adaptation mechanism

This paper proposes a novel adaptation design to replace the classical proportional-integral controller used in model reference adaptive system (MRAS) speed estimation. The proposed adaptation scheme is an association of two fuzzy units. The rules of each module were obtained by user experience and numerical data. In the traditional fuzzy logic controllers, the computational complication enhances with the attributes of the system variable quantities; the number of rules increases incrementally while the number of control variables increases. This negatively affects the response time of the system. This novel design was deduced to reduce the number of rules for a linear function of system variables. By this way, the response of the system became faster. Detailed simulation and experimental results were obtained for comparison of this novel method with traditional MRAS techniques. The results showed that the proposed method was faster in speed tracking and exhibited higher prediction accuracy and less oscillation than the traditional method. Thus, the proposed MRAS method was clearly seen to be applicable and reliable.

Robust Adaptive Control of Pulse-width Modulated Rectifiers Based on Adaptive Super-twisting Sliding-mode and State Feedback Controllers

Abstract—This article proposes a new robust adaptive hybrid controller for three-phase pulse-width modulated rectifiers to improve control performance. This hybridization is implemented by combining the second-order sliding mode with the adaptive gain super-twisting control law in the DC bus voltage control loop and state feedback adaptive control in the d-q-axis current control loops. The control objectives are fourfold: (1) driving the DC bus voltage to a reference signal without using a priori knowledge of the plant parameters, (2) forcing the d-q-axis current errors to zero, (3) assuring a satisfactory power factor correction in relation to the AC source, and (4) eliminating the chattering effect. In the closed-loop control system, three-phase source currents and the DC bus voltage are supposed to be available for feedback. As a result, no a priori knowledge of the plant parameters is necessary in the design of the proposed controller. In addition, the proposed controller does not have the disadvantages of singularity, over-parameterization, and chattering phenomenon. Results of experimental studies prove that the proposed control system guarantees the tracking of reference signals with high performance despite all the parameter and external disturbance uncertainties.

Integration and control of an off-grid hybrid wind/PV generation system for rural applications

This study focuses on a stand-alone hybrid system combining photovoltaic/wind with super-capacitor/battery storage for rural residential applications. Various DC/DC converters are used to control the power flow to the load and Maximum Power Point Tracker (MPPT) is used for maximum power extraction from the photovoltaic/wind systems. In the proposed architecture, the Photovoltaic (PV) has the priority to meet the required load. A wind turbine system is integrated in the system to support PV during demand. Both super-capacitor and battery are used as an energy storage system during surplus power and/or backup device during demand. The proposed system operates in such a way to maintain the State of Charge (SoC) of battery above 80%, which consequently improves the battery life and its performance. The proposed system uses real time solar, wind data and a load of five rural households available at the University of Nottingham, Malaysia campus. MATLAB simulation results conclude that the proposed system can compensate power fluctuation and meet the required load without any grid connections.

Değişken Hızlı Rüzgâr Türbinlerinde Kanat Ucu Hız Oranı Tabanlı Maksimum Güç İzleme Denetimi; Kapsamlı Bir Tasarım

The most primitive control method of wind turbines used to generate electric energy from wind is the fixed speed control method. With this method, it is not possible that turbine input power is transferred to grid at maximum rate. For this reason, Maximum Power Tracking (MPT) schemes are proposed. In order to implement MPT, the propeller has to rotate at a different speed for every different wind speed. This situation has led MPT based systems to be called Variable Speed Wind Turbine (VSWT) systems. In VSWT systems, turbine input power can be transferred to grid at rates close to maximum power. When MPT based control of VSWT systems is the case, two important processes come into prominence. These are instantaneously determination and tracking of MPT point. In this study, using a Maximum Power Point Tracking (MPPT) method based on tip speed ratio, power available in wind is transferred into grid over a back to back converter at maximum rate via a VSWT system with permanent magnet synchronous generator (PMSG). Besides a physical wind turbine simulator is modelled and simulated. Results show that a time varying MPPT point is tracked with a high performance.Ruzgârdan elektrik enerjisi uretmek icin kullanilan ruzgâr turbinlerinin en ilkel denetim yontemi, sabit hizli denetim yontemidir. Bu yontemle, turbin giris gucunun maksimum oranda sebekeye aktarilmasi mumkun degildir. Bu nedenle Maksimum Guc Izleme (MGI) semalari onerilmistir. MGI yapabilmek icin ruzgâr hizinin her farkli degerinde, pervane farkli bir hizla donmelidir. Bu durum MGI tabanli sistemlere Degisken Hizli Ruzgâr Turbini (DHRT) sistemleri denilmesine yol acmistir. DHRT sistemlerinde turbin giris gucu maksimum guce yakin oranlarda sebekeye aktarilabilmektedir. DHRT sistemlerinin MGI tabanli denetimi soz konusu oldugunda iki onemli islem one cikar. Bunlar MGI noktasinin anlik olarak saptanmasi ve izlenmesidir. Bu calismada kanat ucu hiz orani tabanli maksimum guc izleme semasi kullanilarak, Sabit Miknatisli Senkron Generatorlu (SMSG) bir DHRT sistemi ile ruzgârda bulunan guc degeri maksimum oranda arka arkaya bagli cevirici sistem uzerinden sebekeye aktarilmaktadir. Ayrica fiziksel bir ruzgâr turbini modellenmis ve benzetimi yapilmistir. Sonuclar zamanla degisen bir MGI noktasinin yuksek performansla izlendigini gostermektedir.

Robust hybrid sensorless control of variable speed wind turbine with permanent magnet synchronous generator

Bu çalışmada, Sabit Mıknatıslı Senkron Generatör (SMSG) sürücü sisteminin değişken hızlarda dinamik cevabını iyileştirmek ve hız (mekanik) sensörsüz çalışma sağlamak için hibrit bir gözlemleyici ile birlikte ikinci dereceden kayan kipli hız denetimci beraber önerilmektedir. Önerilen denetim sisteminde, anlık hız değişimi ve parametre değişimleri gibi bozucu etkilerin var olduğu durumlarda, sürücü sisteminde mekanik sensör kullanılmadan dış bozucu etkilere karşı dayanıklı hız cevabının elde edilmesi amaçlanmaktadır. SMSG’ün denetiminde, gözlemleyici-denetleyici yapısının basit ve uygulanabilirliğinin kolay olması amacıyla ikinci dereceden kayan kipli gözlemleyici (üstün burulma algoritması) ve basit bir Kalman Filtresi yapısı kullanılmaktadır. Bu sayede, klasik kayan kip gözlemleyicidenetimci yapısının önemli dezavantajlarından biri olan çatırdama etkisi azaltılmakta ve hız referansı değişimlerine karşı iyi bir dinamik hız cevabı elde edilmektedir. Sonuçlar, klasik kayan kip gözlemleyici yapısı ile karşılaştırılmakta ve aralarındaki farklar gösterilmektedir. In this study, in order to improve dynamic performance of variable speed Permanent Magnet Synchronous Generator (PMSG) drive system and obtain a speed (mechanic) sensorless operation, a second order sliding mode controller together with a hybrid observer are proposed. In the presence of instantaneous speed change and disturbance effects such as parameter and load torque deviations, it is aimed at developing a robust speed response against all uncertainties without using a mechanical sensor in the drive system. In controlling PMSG, a second order sliding mode observer and a simple Kalman Filter, hybrid structure, are utilized in view of their simple observer-controller structure. Thanks to this the structure, chattering effect, one of the important disadvantages of classical sliding mode observer-controller structure, is reduced and a good dynamic speed response is yielded in variable speed operation. Results are compared to classical sliding mode and differences between the hybrid observer-controller and the classical system are revealed.