Considering the internal and external disturbances in wind energy conversion systems, a predictive active disturbance rejection control (PADRC) strategy for a direct-driven permanent magnet synchronous generator (PMSG)-based wind energy conversion system, is proposed to maximize the wind power extraction in this paper. First, the proposed PADRC method can successfully deal with the effects of the uncertainties in the internal dynamics, modeling error, external forces and the variety of wind speeds, since it inherits the merits of active disturbance rejection control (ADRC). Second, the introduction of Smith Predictor can overcome the time delay in wind turbine system to guarantee the maximum power tracking performance for different wind speeds. Finally, simulation studies are conducted to evaluate power tracking performances of the proposed control strategy. It is shown that the proposed PADRC strategy exhibits significant improvements in both maximum power tracking performance and anti-disturbance ability compared with the traditional ADRC approach.

The piezoelectric smart structures, which can be labeled as the cream of the crop of smart structures without overstatement, are strongly impacted by a large number of uncertainties and disturbances during operation. The present paper reviews active disturbance rejection control (ADRC) technologies developed for application in piezoelectric smart structures, focusing on measurement, analysis, estimation, and attenuation of uncertainties/disturbances in systems. It first explained vast categories of uncertainties/disturbances with their adverse influences. Then, after a brief introduction to the application of basic ADRC in smart structures, a thorough review of recently modified forms of ADRC is analyzed and classified in terms of their improvement objectives and structural characteristics. The universal advantages of ADRC in dealing with uncertainties and its improvement on the particularity of smart structures show its broad application prospects. These improved ADRC methods are reviewed by classifying them as modified ADRC for specific problems, modified ADRC by nonlinear functions, composite control based on ADRC, and ADRC based on other models. In addition, the application of other types of active anti-disturbances technologies in smart structures is reviewed to expand horizons. The main features of this review paper are summarized as follows: (1) it can provide profound understanding and flexible approaches for researchers and practitioners in designing ADRC in the field and (2) light up future directions and unsolved problems.

This paper focuses on the control problem of wind energy conversion systems (WECSs) with direct-driven permanent magnet synchronous generator (PMSG) working in variable power output stage. A novel compound control scheme combined the active disturbance rejection controller (ADRC) and speed sensorless technology is proposed. In order to achieve maximum power point tracking (MPPT), a speed control loop is designed based on ADRC to improve the speed tracking ability and anti-disturbance ability of system. Moreover, considering the large amount of system model information, a model-assisted ADRC is designed on the nominal ADRC to improve the response speed of system and reduce the energy consumption for the system control. Additionally, to solve the contradiction between the requirement of speed sensor precision and the economy of system design, a speed observer based on current model is designed in α-β coordinate system. Furthermore, a resistance observer is introduced to improve the convergence rate of the observer. And a position sensorless observer structure based on the speed observer is proposed. Finally, simulation studies are conducted to evaluate power tracking performances of the proposed speed-observer-based model assisted ADRC technology. It is shown that the proposed compound scheme exhibits significant improvements in both control performance and anti-disturbance ability with high observation precision compared with the normal ADRC method.

This paper aims to investigate the disturbance estimation mechanism of extended state observer (ESO) from a new perspective: a time-delay estimation (TDE) interpretation. By drawing the concept of input-output linearization, ESO is transformed into an equivalent TDE form in frequency domain. The establishment of this relationship can lead to an improved understanding of ESO’s principle. In addition, ESO’s parameters for disturbance estimation are given with explicitly physical meanings. Furthermore, theoretical analysis from this perspective also results in a quantitative relationship between ESO estimation performance and its two tuning parameters including control gain $b_0$ and bandwidth $\omega _o$ . Theoretical results are evaluated by using an all-clamped plate structure with an inertial actuator, which is considered to be a typical benchmark for active vibration control. Extensive comparative experiments validate algorithm effectiveness. Note to Practitioners —This paper was focused on the ability of extended state observer (ESO) to estimate total disturbances. The controlled system is a typical benchmark for active vibration control consisting of an all-clamped plate structure with an inertial actuator. The model uncertainties and external disturbances that bothers the system is compensated by the real-time estimation of the ESO. In order to facilitate practical engineering applications, the distinct physical meanings of ESO parameters are expounded with the help of the relationship between ESO and time delay estimation (TDE) established in frequency domain. Moreover, the influence of parameters control gain $b_0$ and bandwidth $\omega _o$ on ESO is qualitatively established. Therefore, the engineer can avoid fall into a trial-and-error strategy that could be laborious and time-consuming. Thus, this paper proposed a convenient way for practitioners interested in developing anti-disturbance control strategies based on ESO. The simplicity and the partial-model-based characteristics are also profitable in practice. Potential applications include robotic systems, smart structures and electrical drives. In the future, the improvements of ESO based on the proposed method to deal with the intractable disturbances should be taken in an effort.