Método de control para dispositivos de compensación dinámicos (SVC) mediante algoritmos de control óptimo basado en la norma H-Inf

La presente investigación desarrolla un sistema de control óptimo para dispositivos de compensación dinámico conectados a las Micro-redes híbridas en AC. Las perturbaciones que existen en el sistema eléctrico tienen su origen por conexión y desconexión de cargas, las cuales hacen variar de forma notable los perfiles de voltaje. El controlador óptimo propuesto está basado en la norma H∞ que busca el rechazo de perturbaciones a la entrada de la Micro-red Híbrida en AC y mejorar la robustez del control para sistemas altamente no lineales como el SVC. La Micro-red en AC, el controlador del SVC, son simulados mediante el software Matlab-Simulink. En el desarrollo del presente documento se puede apreciar un resultado favorable de la señal del voltaje entre el esquema del control por H∞ y un esquema clásico, destacándose el control óptimo propuesto por su mejor comportamiento dinámico y un mejor rechazo a perturbaciones.This research develops an optimal control system for dynamic compensation devices connected to AC Hybrid Microgrids. The disturbances that exist in the electrical system have their origin by connection and disconnection of loads, which get the voltage profiles to vary significantly. The proposed optimal controller is based on the H∞ standard that seeks the rejection of disturbances at the input of the AC Hybrid Microgrid and improves the robustness of the control for highly nonlinear systems such as the SVC. The AC Microgrid, the SVC controller, is simulated using Matlab- Simulink software. In the development of this paper, it can be appreciated a notorious favorable result of the voltage signal between the H∞ control scheme and a classical scheme, highlighting the proposed optimal control for its better dynamic behavior and better rejection to disturbances

Recent Advances of Wind-Solar Hybrid Renewable Energy Systems for Power Generation: A Review

A hybrid renewable energy source (HRES) consists of two or more renewable energy sources, such as wind turbines and photovoltaic systems, utilized together to provide increased system efficiency and improved stability in energy supply to a certain degree. The objective of this study is to present a comprehensive review of wind-solar HRES from the perspectives of power architectures, mathematical modeling, power electronic converter topologies, and design optimization algorithms. Since the uncertainty of HRES can be reduced further by including an energy storage system, this paper presents several hybrid energy storage system coupling technologies, highlighting their major advantages and disadvantages. Various HRES power converters and control strategies from the state-of-the-art have been discussed. Different types of energy source combinations, modeling, power converter architectures, sizing, and optimization techniques used in the existing HRES are reviewed in this work, which intends to serve as a comprehensive reference for researchers, engineers, and policymakers in this field. This article also discusses the technical challenges associated with HRES as well as the scope of future advances and research on HRES

실 계통에 기반한 소규모 하이브리드 AC/DC 독립형 마이크로그리드 모델링 및 제어전략 수립

학위논문 (석사)-- 서울대학교 대학원 공과대학 전기·정보공학부, 2017. 8. 문승일.Hybrid AC/DC standalone microgrid(MG) is considered as the prominent formation that can be a major type of MG which is essential to realize small scale, distributed and decentralized power system in the future. Based on the two MG projects performed in the same island located near the west-south coast of Korea, Geocha-island has become the place to be able to provide the meaningful opportunity to realize the test-bed project of hybrid AC/DC MG for the first time in the world as far as the author is aware of. As a first step to implement hybrid AC/DC MG configuration in Geocha-island, the modeling work has been done based on the design information of pre-existing AC MG and DC MG. In the process of the combining two MGs, interlinking converter (ILC) is only added at the point of connection to transfer the proper amount of active power between MGs required to achieve system control purposes such as system voltage control in DC MG, system frequency control in AC MG and constant active power transfer. Secondly, the control strategy of hybrid AC/DC MG in Geocha-island is established based on the modeling result performed in this paper. It is composed of five types of control mode in normal operation and two types of control mode in contingency operation. Each of mode has individualized control scheme in order to guarantee the reliable operation of the whole system at most cases. At last, the effectiveness of the proposed control strategy is verified through the simulation using Matlab/Simulink for several normal and contingency operation cases. The simulation results clearly show that hybrid AC/DC MG in Geocha-island can be operated reliably while satisfying the given grid codes and performing better than individual MG operation case. Consequently, developing the control strategy for hybrid AC/DC MG in Geocha-island and verifying its usefulness for the future application are the main contributions of this dissertation.하이브리드 AC/DC 독립형 마이크로그리드(MG) 는 소규모, 분산, 비집중화된 발전 방식 중심의 미래 차세대 전력망을 구현하는데 필수적인 MG의 주요형태로 발전할 것이 예상되는 한편, 국내 전남 서해안에 위치한 거차도에서는 2개의 다른 계통 형태의(AC/DC) MG 실증사업이 완료 또는 진행 중인 상태로, 이를 활용 향후 세계 최초의 하이브리드 AC/DC 독립형 MG 구축사업 추진을 위한 선행연구로써 본 연구를 진행하게 되었다. 거차도에 하이브리드 AC/DC MG 구현을 위한 첫 번째 과정으로서, 기존의 AC MG 및 DC MG 실증사업 내용을 바탕으로 모델링 작업을 진행하였다. 이 때, 두 개의 MG 물리적 접속점에 설치되어 적정한 양의 유효전력을 전달함으로써, DC MG의 계통전압 제어, AC MG의 계통주파수 제어, MG 간 일정 유효전력 전달의 역할을 구현할 수 있는 연계 컨버터의 제어모델을 새롭게 제안하였다. 다음으로, 앞에서 수행한 거차도 모델링 결과를 기반으로 하이브리드 AC/DC MG 제어전략을 수립하였다. 본 전략은 정상운영 상태에서의 5가지 제어모드, 비상운영 상태에서의 2가지 제어모드, 총 7가지 제어모드로 구성되어 계통 내 발생 가능한 모든 상황에서 전체 MG 계통의 안정적 운전을 보장 할 수 있도록 구성되었다. 각 모드는 개별 제어목적에 따라 MG 내 제어 가능한 요소 기기별 상이한 제어방법을 활용토록 설계되었다. 마지막으로, 제안된 제어전략의 유효성을 검증하기 위해 다양한 정상 및 비상운전 시나리오에 대해서 Matlab/Simulink를 활용한 시뮬레이션을 시행하였다. 그 결과, 거차도 하이브리드 AC/DC MG 가 주어진 계통운전 조건을 만족시키면서 안정적으로 운영될 수 있고, 개별 MG로 운전 될 경우보다 더 나은 성능을 발휘 할 수 있음을 검증하였다. 결론적으로, 새롭게 모델링한 거차도 하이브리드 AC/DC MG의 제어전략을 개발하고, 향후 활용을 위해 그 유효성을 시뮬레이션을 통해 검증한 것이 본 논문의 주요 기여점이다.Chapter 1 Introduction 1 1.1 Backgrounds 1 1.2 Review of the research progress in MG 4 1.3 Review of MG projects in Korea 6 1.4 Motivations and purposes 8 1.5 Thesis outline 10 Chapter 2 Modeling of Hybrid AC/DC MG 12 2.1 Modeling of existing MGs in Geocha-island 15 2.1.1 Configurations of AC and DC MGs 15 2.1.2 Modeling of DGs and converters 21 2.2 Modeling of a hybrid AC/DC MG in Geocha-island 29 2.2.1 Configuration 30 2.2.2 Modeling of interlinking converter 32 Chapter 3 Control strategy of Hybrid AC/DC MG 34 3.1 Normal operation 36 3.1.1 Mode 1 : Constant P transfer 37 3.1.2 Mode 2 : SOC limit of BESSDC reached 39 3.1.3 Mode 3 : SOC limit of BESSAC reached 40 3.1.4 Mode 4 : SOC limit of BESSDC&AC reached 41 3.1.5 Mode 5 : BESS output dispatch 43 3.2 Contingency opeartion 44 3.2.1 Mode 6 : Grid separation 44 3.2.2 Mode 7 : Ready for re-connection 45 Chapter 4 Simulation Results 46 4.1 Normal cases 46 4.1.1 Case 1 : BESSDC discharging 49 4.1.2 Case 2 : BESSAC charging 52 4.1.3 Case 3 : Case 1 to Case 2 56 4.1.4 Case 4 : Case 2 to Case 1 60 4.2 Contingency cases 64 4.2.1 Interlinking converter off 64 4.2.2 Re-conncection 65 Chapter 5 Conclusions and Further Studies 68 5.1 Conclusions 68 5.2 Suggestions 69 5.3 Future works 71 Bibliographies 72 Appendix A Details of MG projects in Geocha-island 75 Appendix B Site Images in Geocha-island 77Maste