論文 / 著書情報
Article / Book Information
題目(和文)

動的ネットワークシステムにおける制御器群の分散設計

Title(English)

Distributed Design of Controllers in Dynamical Network Systems

著者(和文)

笹原帆平

Author(English)

Hampei Sasahara

出典(和文)

学位:博士(工学),学位授与機関:東京工業大学,
報告番号:甲第11128号,
授与年月日:2019年3月26日,
学位の種別:課程博士,
審査員:井村 順一,藤田 政之,三平 満司,山北 昌毅,早川 朋久,畑中 健志

Citation(English)

Degree:Doctor (Engineering),Conferring organization: Tokyo Institute of Technology,
Report number:甲第11128号,
Conferred date:2019/3/26,
Degree Type:Course doctor,Examiner:,,,,,

学位種別(和文)

博士論文

Category(English)

Doctoral Thesis

種別(和文)

論文要旨

Type(English)

Summary

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（博士課程）Doctoral Program論 文 要 旨ＴＨＥＳＩＳ ＳＵＭＭＡＲＹ

系・コース：
Department of, Graduate major in

システム制御システム制御学生氏名：
Student’s Name

笹原 帆平

系コース

申請学位（専攻分野）：

博士

Academic Degree Requested

Doctor of

指導教員（主）：Academic Supervisor(main)（工学井村順一）

指導教員（副）：Academic Supervisor(sub)要旨（英文 800 語程度）
Thesis Summary （approx.800 English Words ）This thesis provides a line of work on distributed design of structured controllers for large-scale dynamicalnetwork systems. Although most existing distributed controller design methods are built on the premise that thecontrollers are designed and integrated in a centralized manner, actual network systems are managed by multiple
operators in many cases and each subcontroller is independently designed by its own operator based only on themodel of the corresponding subsystem. In this thesis, novel distributed design methods for decentralizedcontrollers and distributed controllers are proposed. In Chapter 2, we consider distributed design problem ofdecentralized controllers for a large-scale network system that is stably operated. There are multiple operatorswith the aim of suppressing effects of disturbance injected into the network system by implementing
subcontrollers. Each operator can attach a subcontroller to the corresponding subsystem but the subcontroller
design is performed based only on the subsystem model without the other subsystems and the network, calledenvironment. The difficulty here is that existing controller design methods cannot deal with the unknown
environment and even stability of the resulting system cannot be guaranteed. We propose a local controller
design method based on retrofit control to surmount the difficulty. In the proposed framework, the targeted
network system is treated as an interconnected system composed of the subsystem of interest and anenvironment whose model is unknown for the designer. Retrofit controllers are defined as controllers thatguarantee internal stability for any possible environment as long as the original network system is internallystable. We first show that all retrofit controllers can be characterized in an algebraic manner in the frequency
domain. Considering a tractable class of retrofit controllers that can be explicitly parameterized we reveal that all
output-rectifying retrofit controllers have the structure that composes a locally stabilizing controller and arectifier under the assumption that the interconnection signal from the environment is available in the controller.
Then we propose a systematic design method for retrofit control It is also shown that a dual structure can beobserved inside all input-rectifying retrofit controllers when control input can be injected into theinterconnection signal to the environment. We generalize the result in Chapter 3 by removing the assumption,
the interconnection signal is available for feedback control, made in Chapter 2. We focus on the situation where
only the state of the subsystem of interest can be fed back into the controller and show that all state-feedback
output-rectifying retrofit controllers have a structure similar to the previous one in this case as well. In Chapter
4, we consider the power system stabilizer design problem for frequency control in power grids with renewableenergy resources. The frequencies of every synchronous generator in a large power grid is necessarily kept to bearound the nominal value; otherwise these lose synchronism and a fatal fault, e.g., blackouts, occurs. We first
give a mathematical model of EAST30, which is a benchmark model of the power grid in the eastern half ofJapan, that composed of synchronous machines, loads, PV generators in addition to buses that form the network.
We show that the power grid can be regarded as an interconnected system treated in Chapter 2 and 3 and apply
the proposed approach for the power system stabilizer design problem. A numerical simulation is shown todemonstrate the effectiveness of the proposed approach. In Chapter 5, we consider the problem of integration ofsupervising controller design and decentralized local controller design for network systems. We generalize theabove approach to glocal (global/local) control, where spatially distributed decentralized controllers and acentral broadcasting controller cooperatively manage the entire network system. The concept of glocal control
has been already introduced in the existing work but a systematic design of glocal controllers has not been fully
established yet. A novel glocal control method based on hierarchical representation, whose notion is newly
introduced in this work, is proposed. Given the definition of hierarchical representation, we derive a necessary
and sufficient condition for existence of hierarchical representation for a network system. Based on thehierarchical representation, we propose a linear function observer that preserves the hierarchical structure anddistributed design of global and local controllers is achieved with the observer. The design procedure ofcontrollers is independently performed and it indicates that the controllers can be designed in a distributedmanner. It is shown that both of local and global behaviors are simultaneously suppressed thanks to the existenceof the global controller. A numerical example with EAST30 is shown to illustrate the effectiveness of theproposed glocal control method. Finally, Chapter 6 draws conclusion and future research direction.
備考 : 論文要旨は、和文 2000 字と英文 300 語を 1 部ずつ提出するか、もしくは英文 800 語を 1 部提出してください。
Note : Thesis Summary should be submitted in either a copy of 2000 Japanese Characters and 300 Words (Engｌish) or 1copy of 800
Words (English).
注意：論文要旨は、東工大リサーチリポジトリ（T2R2）にてインターネット公表されますので、公表可能な範囲の内容で作成してください。
Attention: Thesis Summary will be published on Tokyo Tech Research Repository Website (T2R2).