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Current control of LCL grid-connected inverter based on ADRC
Published in Xiaoling Jia, Feng Wu, Electromechanical Control Technology and Transportation, 2017
Jian Sun, Hejin Xiong, Deming Lei
The technology of active disturbance rejection control is a kind of control theory, which is based on the control thought and the development of the nonlinear control technology. The active disturbance rejection control technology does not comply with the classification of disturbances, but unifies the perturbation and expands a state by its own internal expansion state observer to characterize the unified disturbance. The compensation of this disturbance reflects the excellent control idea of the active disturbance rejection control, which can still maintain the precision and show a strong robustness to the harsh environment. It also shows a wide range of application prospects. The application of active disturbance rejection control technology shows that the ADRC has a strong robustness and adaptability to the controlled object with nonlinear, large time delay and bad environment change.
Microgrid control design with RES and electric vehicle integration
Published in Rajkumar Viral, Anuradha Tomar, Divya Asija, U. Mohan Rao, Adil Sarwar, Smart Grids for Renewable Energy Systems, Electric Vehicles and Energy Storage Systems, 2023
The nonlinear active disturbance rejection control technique (ADRC) was proposed by Professor Han as an alternative to both classical and modern control techniques [12, 13]. It comprises of an extended state observer (ESO), which estimates not only the nominal states of the system, but also the combined effect of external disturbances and internal uncertainties via an additional state, which is commonly called the generalized disturbance or the total disturbance. Subsequently, the estimates of the states and the generalized disturbance are utilized in the state feedback-based control law, which is formulated such that the effect of generalized disturbance is attenuated in the overall controlled system. However, the nonlinear ADRC technique is complex and the number of tuning parameters in the nonlinear ADRC technique are large. To simplify the tuning procedure, the ESO and the estimated state feedback-based control law were linearized, leading to the development of the linearized active disturbance rejection control (LADRC) technique [14, 15]. The LADRC controller can be designed largely independent of the model-plant information and entails the tuning of only two parameters, namely observer bandwidth and controller bandwidth, which are directly linked to the performance of the system [16]. Several applications of ADRC techniques are given in [7, 17–21]. To demonstrate the load frequency control of a hybrid microgrid via linearized active disturbance rejection control technique, an elaborate case study and a comprehensive analysis is conducted. The sharing of power demand amongst the renewable sources of energy, energy storage systems and non-renewable sources in a hybrid microgrid, when a load perturbation occurs is shown via simulation results. The nature of load perturbations is considered as step variations to explain the load sharing mechanism, and random variations to mimic the practical load conditions prevailing in a particular area. An elaborate comparative analysis is undertaken, wherein the load frequency control of the hybrid microgrid system is shown in the absence and the presence of an LADRC controller. The simulation results establish the efficacy of the LADRC technique.
Disturbance rejection of T–S fuzzy systems: a membership function-dependent EID method
Published in International Journal of Systems Science, 2023
Shengnan Tian, Kang-Zhi Liu, Manli Zhang, Chengda Lu, Luefeng Chen, Min Wu, Jinhua She
As is well known, disturbance degrades control performance (Zhao et al., 2022; L. Zou et al., 2022). For example, the measurement disturbances greatly reduce the state estimation performance of complex networks (L. Zou et al., 2021). Therefore, the suppression of disturbance is a core issue in system control. The disturbance estimation and compensation method based on two-degrees-of-freedom is a prevailing method, including the active disturbance rejection control (Z. M. Li et al., 2022), the generalised extended state observer (GESO) (M. Wu et al., 2017), the disturbance-observer-based method (Icon & Das, 2022) as well as the equivalent-input-disturbance (EID) method (J. X. Wang & Yu, 2022; Zhou et al., 2020). The first three methods require the disturbance estimation to meet the matching condition or select an appropriate compensation gain. On the contrary, the EID approach requires neither prior information of disturbance nor the matching condition. It is widely extended to nonlinear systems (Yan et al., 2021), time-delay systems (M. L. Li et al., 2020), uncertain systems (Yu et al., 2020), singular systems (Gao et al., 2020), and fractional-order systems (R. J. Liu et al., 2018). In particular, the EID approach has been successfully applied to practical systems such as dual-motor rotational control system (She et al., 2008), networked control systems (X. Wu et al., 2022), and magnetic levitation system (J. X. Wang et al., 2022).
Tracking control and identification of interaction forces for a rehabilitative training walker whose centre of gravity randomly shifts
Published in International Journal of Control, 2021
Ping Sun, Shuoyu Wang, Hongbin Chang
Several results have been reported related to the problem of assessing an external disturbance via a suitable observer. In Ha and Back (2018) and Yang, Yang, Chen, and Na (2017), a disturbance observer was designed using the relationship between system states and disturbance variable, whereupon the constructed controller compensated for the disturbance. Unfortunately, the design technique of that conventional observer is limited because it is difficult to structure the relationship between the interaction forces and robot's motion states. In Xue et al. (2015) and Yang, Fan, Shi, and Hua (2016), an extended state observer was proposed in the active disturbance rejection control technique in which the system states and total disturbance estimation were described using the common nonlinear function. However, with that type of observer, it is difficult to choose υ and σ so that convergence is guaranteed (Zhao & Guo, 2017). Meanwhile, the universal function is not appropriate for estimating the interaction forces while ignoring the motion feature of the human–robot. In the present study, we investigate anew the interaction forces of a human–robot system, thereby revealing the cause of the unsatisfactory tracking precision. We then eliminate this disadvantageous influence on trajectory tracking by using stochastic control technology.
Stabilization of a constrained one-link flexible arm with boundary disturbance
Published in International Journal of Control, 2021
In this paper, we consider the stabilisation problem of a constrained one-link flexible arm with boundary disturbance flowing to the control end. The active disturbance rejection control approach is employed to estimate the disturbance, in which the can be regarded as the estimation of d. Hence, we design a feedback controller so that the disturbance is cancelled in the feedback loop. Moreover, the closed-loop system is well-posed in whole state space by applying the semigroup theory. Finally, under different assumptions of the time varying high gain function, the asymptotical stability and the exponentially stability of the closed-loop system are illustrated by the Lyapunov function approach.