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Novel Unit Commitment Approach for Wind Farm
Yonghao Gui,Chung Hun Kim,Young Ok Lee,Chung Choo Chung 제어로봇시스템학회 2012 제어로봇시스템학회 국제학술대회 논문집 Vol.2012 No.10
Due to increasing of the wind power penetration in power systems, centralized control for a wind farm is needed to connect to the grid. This paper describes an optimal unit commitment problem, which is a part of wind farm centralized control that schedules the wind turbines of wind farm to satisfy the demand power from transmission system operator. Four binary variables are introduced to formulate a new objective function which is to minimize the sum of expected production cost, the expected cost of unserved energy, start-up and shut-down cost of each turbine. Different scenarios are illustrated in the illustrative example, which is consisting of 10 wind turbines, by using the proposed method. Simulation results show that adjusting the coefficients in the objective function can schedule the commitment of wind turbines according to the transmission system operator.
Novel Passivity-Based Controller Design for STATCOM
Yonghao Gui,Young Ok Lee,Hyun Jae Kang,Youngseong Han,Chung Choo Chung 제어로봇시스템학회 2011 제어로봇시스템학회 국제학술대회 논문집 Vol.2011 No.10
This paper presents the design of the passivity-based control (PBC) for type 2 static synchronous compensator (STATCOM). The PBC controller, which consists of a desired control input and a new control input considering the performance of all states, are designed. PBC guarantees the exponentially stability of equilibrium point of the system. The PBC controller’s the performance is compared with input-output linearization (IOL) controller’s. Simulation results show that better performances of capacitive voltage and active current are achieved using PBC than IOL.
Yonghao Gui,이길하,김청훈,정정주 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.5
This paper presents a new direct active and reactive power control (DPC) scheme for a three-phase gridconnected voltage source inverter (VSI) based on the passivity viewpoint using the port-controlled Hamiltonian(PCH) system. The proposed controller consists of feedforward and feedback parts. The feedforward part (the referenceinputs) is generated through the flatness of the dynamics of the VSI model, which makes the error dynamicsin the form of PCH system. The nonlinear feedback part is designed to enhance the damping of the error dynamicsby using its Lyapunov function. The proposed control method has an ability of the finite time reaching conditionsimilar to sliding mode control (SMC). Moreover, the exponential stability and uniform performance are guaranteedover all operating points without need for reaching a certain manifold. The proposed method is validated byusing an experiment through hardware-in-the-loop system with a digital signal processor. The experimental resultsfor the proposed method are compared with those using SMC-DPC method. The proposed method significantlyreduces the total harmonic distortion in the output current without deteriorating the transient response of the activeand reactive powers. In addition, it provides robust performance against the line impedance variations and the gridvoltage sag.
Improved Direct Power Control for Grid-Connected Voltage Source Converters
Gui, Yonghao,Kim, Chunghun,Chung, Chung Choo,Guerrero, Josep M.,Guan, Yajuan,Vasquez, Juan C. Institute of Electrical and Electronics Engineers 2018 IEEE transactions on industrial electronics Vol.65 No.10
<P>A novel grid voltage modulated direct power control (GVM-DPC) strategy for a grid-connected voltage source converter is proposed to control the instantaneous active and reactive powers directly. The GVM-DPC method consists of a nonlinear GVM controller, a conventional controller (feedforward and PI feedback), and nonlinear damping. The proposed control strategy shows a relationship between DPC and voltage-oriented control methods designed in <TEX>$d$</TEX>-<TEX>$q$</TEX> frame. The main advantage is that the proposed method makes the system be a linear time-invariant system, which enables us to apply various control methods easily. The GVM-DPC guarantees not only the convergence rate but also the steady-state performance of the system. Moreover, it is ensured that the closed-loop system is exponentially stable. Finally, simulation and experimental results using a 2.2-kVA VSC are provided to validate the tracking performance and robustness of the proposed control architecture. In addition, the total harmonic distortion of the current is 1.9<TEX>$\%$</TEX> which is much less than the requirement for grid operation.</P>
Economic Dispatch for Wind Farm Using Model Predictive Control Method
Yonghao Gui,Chunghun Kim,Chung Choo Chung 제어로봇시스템학회 2013 제어로봇시스템학회 국제학술대회 논문집 Vol.2013 No.10
An economic dispatch (ED) problem of committed turbines is solved minimizing each wind turbine’s output power variation by model predictive control (MPC) method. The proposed method could solve the ED problem on-line using prediction time horizon that could be selected flexibly considering time horizon based on wind forecasting errors. Dispatched wind turbines are classified into three groups considering variations of forecasted power generation: maximum power point tracking, balance control, and delta control. From the simulation study using 10 wind turbines we observed that the proposed method effectively provided the optimal solution to the scenario.
Passivity-Based Control With Nonlinear Damping for Type 2 STATCOM Systems
Yonghao Gui,Wonhee Kim,Chung Choo Chung IEEE 2016 IEEE transactions on power systems Vol.31 No.4
<P>This paper presents a passivity-based control (PBC) for a type 2 static synchronous compensator (STATCOM) based on an Euler-Lagrange model. The proposed method is designed based on a Lyapunov function by considering dissipation to improve transient performance. An additional nonlinear damping term is designed to regulate the capacitor voltage. It is guaranteed that the equilibrium point of the system is locally exponentially stable in the operating range. The performance of the proposed method is validated via a 100 Mvar STATCOM system connected to the 345-kV grid system in SimPowerSystems, MATLAB/Siumlink. To compare with the input-output feedback linearization method, the proposed control method has improved convergence and reduction of oscillations of the active current and DC voltage, as shown in simulation results. Lastly, it shows that the proposed method is robust to model mismatches as the variation of the grid voltage and the degradation of the capacitance.</P>
정정주,Yonghao Gui,김청훈 제어·로봇·시스템학회 2016 International Journal of Control, Automation, and Vol.14 No.5
This paper presents a nonlinear feedback controller for a permanent-magnet synchronous generator(PMSG) wind turbine system based on port-controlled Hamiltonian system. For the simplification, this work focuseson the nonlinear control law of the grid side converter (GSC) that is directly connected to the grid and affectedduring network disturbances. The proposed controller is designed through the analysis of PMSG GSC model fromthe passivity viewpoint in order to regulate the reference of the DC voltage and track the reference of the reactivecurrent. The exponential stability of the equilibrium point of the error dynamics at the origin is guaranteed by usingLyapunov theory. Finally, the proposed method is validated through simulation. The simulation results show thatthe performance has smaller overshoot and faster convergence when the proposed method is used than when theconventional method is used.
Maximum Power Point Tracking of a Wind Power Plant With Predictive Gradient Ascent Method
Kim, Chunghun,Gui, Yonghao,Chung, Chung Choo IEEE 2017 IEEE transactions on sustainable energy Vol.8 No.2
<P>In this paper, we present maximum power point tracking for a wind power plant (WPP) using the gradient ascent (GA) in a data-driven manner. The conventional GA method achieves fast convergent performance by considering only direct wake terms when calculating the axial induction factors. However, the conventional method might not be close to optimal even when the wind conditions are steady state. In this paper, we propose a new method using the relationships between the direct and indirect wake terms. Using the relationship between the wake terms can prevent sudden deviations after convergence to a single operating point, even when significant indirect wake terms exist in the presence of multiple wakes. Therefore, the proposed method provides not only fast convergence to an operating point, but also closer-to- optimal power production without sudden deviations compared to the conventional method. We validated the effectiveness of the proposed method using modeled WPP layouts with various wind conditions.</P>