Robust adaptive excitation control of synchronous generators in multimachine power systems under parametric uncertainties and external disturbances

The main purpose of developing microgrids (MGs) is to facilitate the integration of renewable energy sources (RESs) into the power grid. RESs are normally connected to the grid via power electronic inverters. As various types of RESs are increasingly being connected to the electrical power grid, power systems of the near future will have more inverter-based generators (IBGs) instead of synchronous machines. Since IBGs have significant differences in their characteristics compared to synchronous generators (SGs), particularly concerning their inertia and capability to provide reactive power, their impacts on the system dynamics are different compared to SGs. In particular, system stability analysis will require new approaches. As such, research is currently being conducted on the stability of power systems with the inclusion of IBGs. This review article is intended to be a preface to the Special Issue on Voltage Stability of Microgrids in Power Systems. It presents a comprehensive review of the literature on voltage stability of power systems with a relatively high percentage of IBGs in the generation mix of the system. As the research is developing rapidly in this field, it is understood that by the time that this article is published, and further in the future, there will be many more new developments in this area. Certainly, other articles in this special issue will highlight some other important aspects of the voltage stability of microgrids.

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Adaptive robust H∞, control for nonlinear systems with parametric uncertainties and external disturbances

2003 European Control Conference (ECC) ◽

10.23919/ecc.2003.7085060 ◽

2003 ◽

Author(s):

Min Wu ◽

Lingbo Zhang ◽

Guoping Liu

Keyword(s):

Nonlinear Systems ◽

Parametric Uncertainties ◽

External Disturbances

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Operation Characteristics of Zone 3 Distance Protection in Wind Power Systems with Fixed-Speed Induction Generators

International Journal of Emerging Electric Power Systems ◽

10.2202/1553-779x.2764 ◽

2011 ◽

Vol 12 (4) ◽

Cited By ~ 1

Author(s):

Shenghu Li

Keyword(s):

Power Systems ◽

Wind Power ◽

Reactive Power ◽

Flow Analysis ◽

Load Flow ◽

Synchronous Generators ◽

Induction Generators ◽

Load Flow Analysis ◽

Wind Power Systems ◽

Operation Characteristics

The induction generators (IGs) are basic to wind energy conversion. They produce the active power and consume the reactive power, with the voltage characteristics fragile compared with that of the synchronous generators and doubly-fed IGs. In the stressed system states, they may intensify var imbalance, yielding undesirable operation of zone 3 impedance relays.In this paper, the operation characteristics of the zone 3 relays in the wind power systems is studied. With the theoretical and load flow analysis, it is proved that the equivalent impedance of the IGs lies in the 2nd quadrature, possibly seen as the backward faults by the mho relays, i.e. the apparent impedance enters into the protection region from the left side. The undesirable operation may be caused by more wind power, larger load, less var compensation, and larger torque angle.

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Control of an IPMC Soft Actuator Using Adaptive Full-Order Recursive Terminal Sliding Mode

Actuators ◽

10.3390/act10020033 ◽

2021 ◽

Vol 10 (2) ◽

pp. 33

Author(s):

Romina Zarrabi Ekbatani ◽

Ke Shao ◽

Jasim Khawwaf ◽

Hai Wang ◽

Jinchuan Zheng ◽

...

Keyword(s):

Sliding Mode ◽

External Disturbance ◽

Tracking Error ◽

Working Environment ◽

Parametric Uncertainties ◽

Metal Composite ◽

External Disturbances ◽

Terminal Sliding Mode ◽

Positioning Accuracy ◽

Soft Actuator

The ionic polymer metal composite (IPMC) actuator is a kind of soft actuator that can work for underwater applications. However, IPMC actuator control suffers from high nonlinearity due to the existence of inherent creep and hysteresis phenomena. Furthermore, for underwater applications, they are highly exposed to parametric uncertainties and external disturbances due to the inherent characteristics and working environment. Those factors significantly affect the positioning accuracy and reliability of IPMC actuators. Hence, feedback control techniques are vital in the control of IPMC actuators for suppressing the system uncertainty and external disturbance. In this paper, for the first time an adaptive full-order recursive terminal sliding-mode (AFORTSM) controller is proposed for the IPMC actuator to enhance the positioning accuracy and robustness against parametric uncertainties and external disturbances. The proposed controller incorporates an adaptive algorithm with terminal sliding mode method to release the need for any prerequisite bound of the disturbance. In addition, stability analysis proves that it can guarantee the tracking error to converge to zero in finite time in the presence of uncertainty and disturbance. Experiments are carried out on the IPMC actuator to verify the practical effectiveness of the AFORTSM controller in comparison with a conventional nonsingular terminal sliding mode (NTSM) controller in terms of smaller tracking error and faster disturbance rejection.

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K-Filter Observer Based Adaptive Quantized Decentralized Excitation Control for Multi-Machine Power Systems With the Line Transmission Delays

IEEE Access ◽

10.1109/access.2021.3066794 ◽

2021 ◽

Vol 9 ◽

pp. 51355-51367

Author(s):

Shunjiang Wang ◽

Xiurong Ou ◽

Dianyang Li ◽

Hongzhe Wang ◽

Guoqiang Zhu

Keyword(s):

Power Systems ◽

Excitation Control ◽

Transmission Delays

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Robust finite-time trajectory tracking control for a space manipulator with parametric uncertainties and external disturbances

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/09544100211014754 ◽

2021 ◽

pp. 095441002110147

Author(s):

Qijia Yao

Keyword(s):

Trajectory Tracking ◽

Finite Time ◽

Tracking Control ◽

Disturbance Observer ◽

Control Method ◽

Parametric Uncertainties ◽

External Disturbances ◽

Trajectory Tracking Control ◽

Space Manipulator ◽

Tracking Controller

Space manipulator is considered as one of the most promising technologies for future space activities owing to its important role in various on-orbit serving missions. In this study, a robust finite-time tracking control method is proposed for the rapid and accurate trajectory tracking control of an attitude-controlled free-flying space manipulator in the presence of parametric uncertainties and external disturbances. First, a baseline finite-time tracking controller is designed to track the desired position of the space manipulator based on the homogeneous method. Then, a finite-time disturbance observer is designed to accurately estimate the lumped uncertainties. Finally, a robust finite-time tracking controller is developed by integrating the baseline finite-time tracking controller with the finite-time disturbance observer. Rigorous theoretical analysis for the global finite-time stability of the whole closed-loop system is provided. The proposed robust finite-time tracking controller has a relatively simple structure and can guarantee the position and velocity tracking errors converge to zero in finite time even subject to lumped uncertainties. To the best of the authors’ knowledge, there are really limited existing controllers can achieve such excellent performance under the same conditions. Numerical simulations illustrate the effectiveness and superiority of the proposed control method.

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