Distributed observer-based control law with better dynamic performance based on distributed high-gain observer

2020 ◽  
Vol 51 (4) ◽  
pp. 631-642
Author(s):  
Haotian Xu ◽  
Jingcheng Wang
Keyword(s):  
Dynamic Performance ◽  
High Gain ◽  
Control Law ◽  
High Gain Observer

scholarly journals A High-Gain Observer-Based Adaptive Super-Twisting Algorithm for DC-Link Voltage Control of NPC Converters

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1110 ◽  
Author(s):  
Xiaoning Shen ◽  
Jianxing Liu ◽  
Abraham Marquez ◽  
Wensheng Luo ◽  
Jose I. Leon ◽  
...  
Keyword(s):  
Disturbance Rejection ◽  
High Efficiency ◽  
Dynamic Performance ◽  
High Gain ◽  
Voltage Regulation ◽  
Industrial Applications ◽  
High Gain Observer ◽  
Twisting Algorithm ◽  
The Impact ◽  
Fast Dynamic

Acting as an interface between the grid and many energy systems, the active front-end (AFE) has been widely used in a large variety of industrial applications. In this paper, in order to ensure the fast dynamic performance and good disturbance rejection ability of the AFE, a high-gain observer (HGO) plus adaptive super-twisting algorithm (STA) for the three-level neutral-point-clamped (NPC) converter is proposed. Comparing with the conventional PI control strategy, the proposed controller implements the adaptive STA in the voltage regulator to provide a faster transient response. The gains of the adaptive STA keep varying according to the rules being reduced in steady state but increasing in transient conditions. Therefore, the chattering phenomenon is mitigated and the dynamic response is guaranteed. Additionally, to undermine the impact of external disturbances on the dc-link voltage, a high-efficiency HGO is designed in the voltage regulation loop to reject it. Experimental results based on a three-level NPC prototype are given and compared with the conventional PI method to validate the fast dynamic performance and high disturbance rejection ability of the proposed approach.

scholarly journals Bounded Control of an Actuated Lower-Limb Exoskeleton

2017 ◽  
Vol 2017 ◽  
pp. 1-20
Author(s):  
Michael Oluwatosin Ajayi ◽  
Karim Djouani ◽  
Yskandar Hamam
Keyword(s):  
Lower Limb ◽  
Angular Position ◽  
High Gain ◽  
Joint Torque ◽  
Control Law ◽  
Bounded Control ◽  
Joint Torques ◽  
Lower Limb Exoskeleton ◽  
High Gain Observer ◽  
Angular Velocities

A bounded control strategy is employed for the rehabilitation and assistance of a patient with lower-limb disorder. Complete and partial lower-limb motor function disorders are considered. This application is centered on the knee and the ankle joint level, thereby considering a user in a sitting position. A high gain observer is used in the estimation of the angular position and angular velocities which is then applied to the estimation of the joint torques. The level of human contribution is feedback of a fraction of the estimated joint torque. This is utilised in order to meet the demands for a bounded human torque; that is, τh≤N2,n≤N1,n. The asymptotic stability of the bounded control law without human contribution and the convergence analysis of the high gain observer is verified using Lyapunov-based analysis. Simulations are performed to verify the proposed control law. Results obtained guarantee a fair trajectory tracking of the physiotherapist trajectory.

Path Following of a Ship Sailing in Restricted Waters Based on an Extended Updated-Gain High-Gain Observer

2018 ◽  
Author(s):  
Jianqin Wang ◽  
Zaojian Zou ◽  
Tao Wang
Keyword(s):  
Feedback Control ◽  
State Feedback ◽  
Control Method ◽  
Output Feedback Control ◽  
Path Following ◽  
High Gain ◽  
The State ◽  
State Feedback Control ◽  
Control Law ◽  
High Gain Observer

The paper studies the path following of a ship sailing in restricted waters based on an output feedback control, which consists of a state feedback control law and an extended updated-gain high-gain observer. According to the separation principle, the state feedback control and the extended updated-gain high-gain observer are designed separately. The state feedback control law is designed based on a robust guaranteed cost control method assuming that system states are measurable. Sufficient conditions are given for the control based on a linear uncertain system. The extended updated-gain high-gain observer, whose gains are updated according to the nonlinear functions of available evaluation errors, is used to reconstruct system states. Then the output feedback control is obtained by replacing states value in the state feedback control law with its estimation yielded by the state observer. Numerical simulations confirm the effectiveness of the proposed control method for the path following of a ship sailing in restricted waters.

scholarly journals Performance enhancements of DFIG wind turbine using fuzzy-feedback linearization controller augmented by high-gain observer

2020 ◽  
Vol 11 (1) ◽  
pp. 10
Author(s):  
Kada Boureguig ◽  
Abdellah Mansouri ◽  
Ahmed Chouya
Keyword(s):  
Feedback Linearization ◽  
Fuzzy Logic Controller ◽  
Dynamic Performance ◽  
High Gain ◽  
Lyapunov Theory ◽  
Nonlinear Observer ◽  
High Gain Observer ◽  
Rotor Flux ◽  
Doubly Fed ◽  
The Stability

<span>This paper proposes a feedback linearization control of doubly fed induction generator based wind energy systems for improving decoupled control of the active and reactive powers stator. In order to enhance dynamic performance of the controller studied, the adopted control is reinforced by a fuzzy logic controller. This approach is designed without any model of rotor flux estimation. The difficulty of measuring of rotor flux is overcome by using high gain observer. The stability of the nonlinear observer is proved by the Lyapunov theory. Numerical simulations using MATLAB-SIMULINK shown clearly the robustness of the proposed control, particularly to the disturbance rejection and parametric variations compared with the conventional method.</span>

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