Adaptive Prescribed Performance Output Regulation of Nonlinear Systems with Nonlinear Exosystems

Fujin Jia,Cui Lei,Junwei Lu,Yuming Chu 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.8

The paper studies the prescribed performance output regulation problem for a class of nonlinear uncertain strict-feedback systems which are driven by nonlinear exosystems. Fuzzy logic systems (FLSs) are used to approximate the unknown functions. A fuzzy adaptive observer is designed to estimate the system state. A fuzzy internal model is designed to reject disturbance. Simultaneously, a parameter-type Lyapunov function and L function are designed to ensure the prescribed performance of the system. As illustrated by example, the proposed prescribed performance fuzzy adaptive output feedback control scheme is shown to guarantee semi-globally uniformly ultimately bounded, and the dynamic performance and steady-state performance of the tracking error are dependent on the prescribed performance functions.

金史良『天馬』における知識人の分類

후지네마유코 ( Fujine Mayuko ) 한국일본어교육학회 2015 日本語敎育 Vol.0 No.71

金史良の『天馬』は京城之いう限られた空間の中に、朝鮮之日本の樣□な知識人の姿を描いている。その登場人物は實在の人物之いうよりも、京城で活動する知識人のタイプを見せている之考えられる。そこで本硏究は登場人物に論者の見解之當時の背景を考慮してタイプ付けをして類型分類をするこ之で、當時の知識人階級の狀況について具體的に知るこ之ができるのではないか之考え分析を試みた。その結果、日本人知識人は日帝の絶對權力型、朝鮮人嫌惡型、傍關者型之いうタイプの人物によって「內鮮壹體」之いう政策名にもかかわらず、實際は內地人之朝鮮人が同等になれない政策であるこ之を見せる之同時に理不盡な內地人の姿を描いている。朝鮮人知識人は國の文化を時世に合わせながらも守らない之いけない之いう愛國者型之、新知識を手に入れ、いつ日帝側に轉向するかわからない日本を憧景する型、日本に利用される型之タイプが分けられ、日本に利用される型の主人公玄龍の姿を通して朝鮮人知識人に對して警告を表現している。金史良は玄龍のような轉向作家達を見ながら「已むに已まれぬ氣持」(金史良1973Ⅳ:22) に驅られこの作品を書いた之述べている。しかしそれだけではなく、このような朝鮮內での兩國の知識人の實態を見つめ、そのような知識人之また自分に對する警告の意味を含めて書いたのではないか之いう結果に至った。

Epidemiologic investigation of gastrointestinal pathogens for Korean cats with digestive sign

이미진,Fujin An,Gijong Lee,Jin-ho Park 한국동물위생학회 2022 韓國家畜衛生學會誌 Vol.45 No.2

This study was performed to investigate infectious gastrointestinal diseases in 115 Korean cats (83 indoors and 32 outdoors) with digestive signs such as diarrhea, anorexia or abdominal distention. Detection of infectious pathogens was analyzed using real-time PCR. As a result, 85 of 115 Korean cats were detected with feline corona virus (FCoV), feline parvo virus, Group A rotavirus, Clos-tridium perfringens (C. perfringens ), Campylobacter coli (C. coli ), Campylobacter jejuni , enterotoxi-genic Escherichia coli , enteropathogenic Escherichia coli , Salmonella spp., Tritrichomonas foetus , Cyclospora cayetanensis , and Giardia lamblia . The most frequently detected pathogen was C. per-fringens (52 cats, 61.2%), followed by FCoV (43 cats, 50.6%) and C. coli (16 cats, 18.8%). Also, single infection was the most common (43 cats), followed by double infection in 31 cats, triple infection in 7 cats, and quadruple infection in 4 cats. There was no significant relationship between pathogen de-tection and age, gender, living environment, weather, and diarrhea. However, there was a significant difference between the age group under 1 year and the age group 1∼7 (P value<0.05). In this study, cats with suspected gastrointestinal infection were randomly evaluated, and other factors that could affect pathogen detection were insufficiently considered. For this reason, additional epidemiological investigations with a larger number of cats and sufficient consideration of the causes that may affect the results are needed. Nevertheless, it is thought that this study can also provide valuable informa-tion on gastrointestinal pathogens in Korean cats.

Impedance Coordinative Control for Cascaded Converter in Bidirectional Application

Yanjun Tian,Fujin Deng,Zhe Chen,Xiaofeng Sun,Yanting Hu 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

Two stage cascaded converters are widely used in bidirectional applications, but the negative impedance may cause system instability. Actually the impedance interaction is much different between forward power flow and reversed power flow, which will introduce more uncertainty to the system stability. This paper proposes a control method for the constant power controlled converter in cascaded system, and consequently it can change the negative impedance of constant power converter into resistive impedance, which will improve the cascaded system stability, as well as merge the impedance difference between forward and reversed power flow. This paper addresses the analysis with the topology of cascaded dualactive - bridge converter (DAB) with inverter, and the proposed control method can also be implemented in unidirectional applications and other general cascaded converter system. The effectiveness has been validated by both simulation and experimental results.

Impedance Interaction Modeling and Analysis for Bidirectional Cascaded Converters

Yanjun Tian,Fujin Deng,Zhe Chen,Xiaofeng Sun,Yanting Hu 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

For the cascaded converter system, the output impedance of source converter interacts with the input impedance of load converter, and the interaction may cause the system instability. In bidirectional applications, when the power flow is reversed, the impedance interaction also varies, which brings more uncertainty to the system stability. An investigation is performed here for showing that the forward and reverse interactions are prominently different in terms of dynamics and stability even though the cascaded converter control remains unchanged. An important guideline has been drawn for the control of the cascaded converter. That is when voltage mode converter working as the load converter; the constant power mode converter as the source converter, the system is more stable. The concluded findings have been verified by simulation and experimental results.

Improved Control Strategy for T-type Isolated DC/DC Converters

Dong Liu,Fujin Deng,Yanbo Wang,Zhe Chen 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.4

T-type isolated DC/DC converters have recently attracted attention due to their numerous advantages, including few components, low cost, and symmetrical operation of transformers. This study proposes an improved control strategy for increasing the efficiency of T-type isolated DC/DC converters. Under the proposed strategy, the primary circulating current flows through the auxiliary switches (metal–oxide–semiconductor field-effect transistors) instead of their body diodes in free-wheeling periods. Such feature can reduce conduction losses, thereby improving the efficiency of T-type isolated DC/DC converters. The operation principles and performances of T-type isolated DC/DC converters under the proposed control strategy are analyzed in detail and verified through the simulation and experimental results.

Global Output Feedback Stabilization Control for Nonlinear Systems without Backstepping

Xiao Yan,Hongzheng Quan,Fujin Jia 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.6

In this paper, we study the global output feedback stabilization (GOFS) of nonlinear systems with unknown functions (UFs). Firstly, a lemma is introduced to solve UFs, which avoids the shortcomings of the approximate algorithms. At the same time, this lemma avoids the assumptions of UFs, thus reducing the conservatism of the algorithms. Secondly, based on Lyapunov function analysis, the controller is designed, which solves the GOFS problem of the controlled system. This control algorithm adopts nonbackstepping, so it avoids the complicated calculation of backstepping. Finally, the control algorithm is applied to the Duffing system to verify its effectiveness.

A Dynamic Power Distribution Strategy for Large-scale Cascaded Photovoltaic Systems

Kangan Wang,Xiaojie Wu,Fujin Deng,Feng Liu 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.5

The cascaded H-bridge (CHB) multilevel converter is a promising topology for large-scale photovoltaic (PV) systems. The output voltage over-modulation derived by the inter-module active power imbalance is one of the key issues for CHB PV systems. This paper proposed a dynamic power distribution strategy to eliminate the over-modulation in a CHB PV system by suitably redistributing the reactive power among the inverter modules of the CHB PV system. The proposed strategy can effectively extend the operating region of the CHB PV system with a simple control algorithm and easy implementation. Simulation and experimental results carried out on a seven-level CHB grid-connected PV system are shown to validate the proposed strategy.

Improved Control Strategy for T-type Isolated DC/DC Converters

Liu, Dong,Deng, Fujin,Wang, Yanbo,Chen, Zhe The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.4

T-type isolated DC/DC converters have recently attracted attention due to their numerous advantages, including few components, low cost, and symmetrical operation of transformers. This study proposes an improved control strategy for increasing the efficiency of T-type isolated DC/DC converters. Under the proposed strategy, the primary circulating current flows through the auxiliary switches (metal-oxide-semiconductor field-effect transistors) instead of their body diodes in free-wheeling periods. Such feature can reduce conduction losses, thereby improving the efficiency of T-type isolated DC/DC converters. The operation principles and performances of T-type isolated DC/DC converters under the proposed control strategy are analyzed in detail and verified through the simulation and experimental results.

An Interleaved Five-level Boost Converter with Voltage-Balance Control

Jianfei Chen,Shiying Hou,Fujin Deng,Zhe Chen,Jian Li 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.5

This paper proposes an interleaved five-level boost converter based on a switched-capacitor network. The operating principle of the converter under the CCM mode is analyzed. A high voltage gain, low component stress, small input current ripple, and self-balancing function for the capacitor voltages in the switched-capacitor networks are achieved. In addition, a three-loop control strategy including an outer voltage loop, an inner current loop and a voltage-balance loop has been researched to achieve good performances and voltage-balance effect. An experimental study has been done to verify the correctness and feasibility of the proposed converter and control strategy.