Global Optimal Stabilization of MT-HVDC Systems: Inverse Optimal Control Approach

The stabilization problem of multi-terminal high-voltage direct current (MT-HVDC) systems feeding constant power loads is addressed in this paper using an inverse optimal control (IOC). A hierarchical control structure using a convex optimization model in the secondary control stage and the IOC in the primary control stage is proposed to determine the set of references that allows the stabilization of the network under load variations. The main advantage of the IOC is that this control method ensures the closed-loop stability of the whole MT-HVDC system using a control Lyapunov function to determine the optimal control law. Numerical results in a reduced version of the CIGRE MT-HVDC system show the effectiveness of the IOC to stabilize the system under large disturbance scenarios, such as short-circuit events and topology changes. All the simulations are carried out in the MATLAB/Simulink environment.

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Global Stabilization of a Reaction Wheel Pendulum: A Discrete-Inverse Optimal Formulation Approach via A Control Lyapunov Function

Symmetry ◽

10.3390/sym12111771 ◽

2020 ◽

Vol 12 (11) ◽

pp. 1771

Author(s):

Oscar Danilo Montoya ◽

Walter Gil-González ◽

Juan A. Dominguez-Jimenez ◽

Alexander Molina-Cabrera ◽

Diego A. Giral-Ramírez

Keyword(s):

Optimal Control ◽

Lyapunov Function ◽

Time Domain ◽

Discrete Control ◽

Global Stabilization ◽

Inverse Optimal Control ◽

Reaction Wheel ◽

Control Lyapunov Function ◽

Control Approach ◽

Optimal Control Approach

This paper deals with the global stabilization of the reaction wheel pendulum (RWP) in the discrete-time domain. The discrete-inverse optimal control approach via a control Lyapunov function (CLF) is employed to make the stabilization task. The main advantages of using this control methodology can be summarized as follows: (i) it guarantees exponential stability in closed-loop operation, and (ii) the inverse control law is optimal since it minimizes the cost functional of the system. Numerical simulations demonstrate that the RWP is stabilized with the discrete-inverse optimal control approach via a CLF with different settling times as a function of the control gains. Furthermore, parametric uncertainties and comparisons with nonlinear controllers such as passivity-based and Lyapunov-based approaches developed in the continuous-time domain have demonstrated the superiority of the proposed discrete control approach. All of these simulations have been implemented in the MATLAB software.

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A Novel Adaptive Control Approach Based on Available Headroom of the VSC-HVDC for Enhancement of the AC Voltage Stability

Energies ◽

10.3390/en14113222 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3222

Author(s):

Duc Nguyen Huu

Keyword(s):

Adaptive Control ◽

Voltage Stability ◽

Reactive Power ◽

Control Method ◽

Offshore Wind ◽

Voltage Source ◽

Long Distance ◽

Control Approach ◽

Hvdc System ◽

Voltage Support

Increasing offshore wind farms are rapidly installed and planned. However, this will pose a bottle neck challenge for long-distance transmission as well as inherent variation of their generating power outputs to the existing AC grid. VSC-HVDC links could be an effective and flexible method for this issue. With the growing use of voltage source converter high-voltage direct current (VSC-HVDC) technology, the hybrid VSC-HVDC and AC system will be a next-generation transmission network. This paper analyzes the contribution of the multi VSC-HVDC system on the AC voltage stability of the hybrid system. A key contribution of this research is proposing a novel adaptive control approach of the VSC-HVDC as a so-called dynamic reactive power booster to enhance the voltage stability of the AC system. The core idea is that the novel control system is automatically providing a reactive current based on dynamic frequency of the AC system to maximal AC voltage support. Based on the analysis, an adaptive control method applied to the multi VSC-HVDC system is proposed to realize maximum capacity of VSC for reactive power according to the change of the system frequency during severe faults of the AC grid. A representative hybrid AC-DC network based on Germany is developed. Detailed modeling of the hybrid AC-DC network and its proposed control is derived in PSCAD software. PSCAD simulation results and analysis verify the effective performance of this novel adaptive control of VSC-HVDC for voltage support. Thanks to this control scheme, the hybrid AC-DC network can avoid circumstances that lead to voltage instability.

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Discrete-time inverse optimal control for a reaction wheel pendulum: a passivity-based control approach

Revista UIS Ingenierías ◽

10.18273/revuin.v19n4-2020011 ◽

2020 ◽

Vol 19 (4) ◽

pp. 123-132 ◽

Cited By ~ 1

Author(s):

Oscar Danilo Montoya ◽

Walter Gil-González ◽

Federico Martin Serra

Keyword(s):

Optimal Control ◽

Discrete Time ◽

Point Of View ◽

Control Analysis ◽

Inverse Optimal Control ◽

Reaction Wheel ◽

Control Approach ◽

Control Functions ◽

Passivity Based Control ◽

The Time Domain

In this paper it is presented the design of a controller for a reaction wheel pendulum using a discrete-time representation via optimal control from the point of view of passivity-based control analysis. The main advantage of the proposed approach is that it allows to guarantee asymptotic stability convergence using a quadratic candidate Lyapunovfunction. Numerical simulations show that the proposed inverse optimal control design permits to reach superiornumerical performance reported by continuous approaches such as Lyapunov control functions and interconnection,and damping assignment passivity-based controllers. An additional advantageof the proposed inverse optimal controlmethod is its easy implementation since it does not employ additional states. It is only required a basic discretizationof the time-domain dynamical model based on the backward representation. All the simulations are carried out inMATLAB/OCTAVE software using a codification on the script environment.

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An Inverse Optimal Control Approach to Human Motion Modeling

Springer Tracts in Advanced Robotics - Robotics Research ◽

10.1007/978-3-642-19457-3_27 ◽

2011 ◽

pp. 451-468 ◽

Cited By ~ 3

Author(s):

Katja Mombaur ◽

Jean-Paul Laumond ◽

Anh Truong

Keyword(s):

Optimal Control ◽

Human Motion ◽

Inverse Optimal Control ◽

Motion Modeling ◽

Control Approach ◽

Optimal Control Approach

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A Nonlinear Optimal Control Approach for the Vertical Take-off and Landing Aircraft

Guidance, Navigation and Control ◽

10.1142/s2737480721500126 ◽

2021 ◽

pp. 2150012

Author(s):

G. Rigatos

Keyword(s):

Optimal Control ◽

Control Method ◽

Nonlinear Optimal Control ◽

The Body ◽

Algebraic Riccati Equation ◽

Control Input ◽

Time Step ◽

Control Approach ◽

Vtol Aircraft ◽

Optimal Control Approach

The paper proposes a nonlinear optimal control approach for the model of the vertical take-off and landing (VTOL) aircraft. This aerial drone receives as control input a directed thrust, as well as forces acting on its wing tips. The latter forces are not perpendicular to the body axis of the drone but are tilted by a small angle. The dynamic model of the VTOL undergoes approximate linearization with the use of Taylor series expansion around a temporary operating point which is recomputed at each iteration of the control method. For the approximately linearized model, an H-infinity feedback controller is designed. The linearization procedure relies on the computation of the Jacobian matrices of the state-space model of the VTOL aircraft. The proposed control method stands for the solution of the optimal control problem for the nonlinear and multivariable dynamics of the aerial drone, under model uncertainties and external perturbations. For the computation of the controller’s feedback gains, an algebraic Riccati equation is solved at each time-step of the control method. The new nonlinear optimal control approach achieves fast and accurate tracking for all state variables of the VTOL aircraft, under moderate variations of the control inputs. The stability properties of the control scheme are proven through Lyapunov analysis.

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Secondary Control for Storage Power Converters in Isolated Nanogrids to Allow Peer-to-Peer Power Sharing

Electronics ◽

10.3390/electronics9010140 ◽

2020 ◽

Vol 9 (1) ◽

pp. 140 ◽

Cited By ~ 2

Author(s):

Eva González-Romera ◽

Enrique Romero-Cadaval ◽

Carlos Roncero-Clemente ◽

Mercedes Ruiz-Cortés ◽

Fermín Barrero-González ◽

...

Keyword(s):

Power Flow ◽

Control Method ◽

Low Voltage ◽

Hierarchical Control ◽

Power Converter ◽

Power Sharing ◽

Primary Control ◽

Secondary Control ◽

Control Loops ◽

Energy Interchange

It is usual in literature that power sharing among grid-forming sources of an isolated microgrid obeys their energy rating, instead of economic agreements between stakeholders, and circulating energy among them is usually avoided. However, these energy interchanges make strong sense and classical power sharing methods must be reformulated in the context of prosumer-based microgrids. This paper proposes a secondary control method for a prosumer-based low-voltage nanogrid that allows for energy interchange between prosumers, where storage systems, together with PV generators, are the controllable grid-forming sources. A power flow technique adapted to islanded microgrids is used for secondary control algorithm and the whole hierarchical control strategy for the prosumer converter is simulated and validated. This hierarchical control consists of three stages: tertiary control plans the energy interchange among prosumers, secondary obtains different voltage and power setpoints for each of the grid-forming sources, and, finally, primary control guarantees stable voltage and frequency values within the nanogrid with droop rules. Inner control loops for the power converter are also defined to track setpoints and assure stable performance. Simulation tests are carried out, which prove the stability of the proposed methods and the accuracy of the setpoint tracking.

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USING DYNAMIC NEURAL NETWORKS TO GENERATE CHAOS: AN INVERSE OPTIMAL CONTROL APPROACH

International Journal of Bifurcation and Chaos ◽

10.1142/s0218127401002468 ◽

2001 ◽

Vol 11 (03) ◽

pp. 857-863 ◽

Cited By ~ 25

Author(s):

EDGAR N. SANCHEZ ◽

JOSE P. PEREZ ◽

GUANRONG CHEN

Keyword(s):

Neural Networks ◽

Optimal Control ◽

Chaotic Attractors ◽

Control Law ◽

Inverse Optimal Control ◽

Dynamic Neural Network ◽

Dynamic Neural Networks ◽

New Approach ◽

Control Approach ◽

Optimal Control Approach

This Letter suggests a new approach to generating chaos via dynamic neural networks. This approach is based on a recently introduced methodology of inverse optimal control for nonlinear systems. Both Chen's chaotic system and Chua's circuit are used as examples for demonstration. The control law is derived to force a dynamic neural network to reproduce the intended chaotic attractors. Computer simulations are included for illustration and verification.

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CHAOTIFYING FUZZY HYPERBOLIC MODEL USING ADAPTIVE INVERSE OPTIMAL CONTROL APPROACH

International Journal of Bifurcation and Chaos ◽

10.1142/s0218127404011442 ◽

2004 ◽

Vol 14 (10) ◽

pp. 3505-3517 ◽

Cited By ~ 32

Author(s):

HUAGUANG ZHANG ◽

ZHILIANG WANG ◽

DERONG LIU

Keyword(s):

Optimal Control ◽

Chaotic System ◽

Parameter Tuning ◽

Hyperbolic Model ◽

Inverse Optimal Control ◽

Control Approach ◽

Adaptive Parameter ◽

System A ◽

Tuning Methods ◽

Optimal Control Approach

In this paper, the problem of chaotifying the continuous-time fuzzy hyperbolic model (FHM) is studied. By tracking the dynamics of a chaotic system, a controller based on inverse optimal control and adaptive parameter tuning methods is designed to chaotify the FHM. Simulation results show that for any initial value the FHM can track a chaotic system asymptotically.

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