A Study of Grid-Connected PV System with Power Control Structure

Trung-Kien Vu,Youngsang Bae,Seongjin Oh 전력전자학회 2012 전력전자학술대회 논문집 Vol.2012 No.7

An EM algorithm for GMM parameter estimation in the presence of censored and dropped data with potential application to indoor positioning

Trung Kien Vu,Manh Kha Hoang,Hung Lan Le 한국통신학회 2019 ICT Express Vol.5 No.2

In this paper, a specific type of incomplete data in Wi-Fi fingerprinting based indoor positioning systems (WF-IPS) is presented: censored and dropped mixture data. For fitting this type of data, a censored and dropped Gaussian Mixture Model (CD-GMM) was proposed. Further, an extended version of the Expectation-Maximization (EM) algorithm is developed for estimating parameters of this model. Simulation results demonstrate the effectiveness of the proposed method for parameter estimation.

Impact of Mobility Prediction on Routing Overhead of On-Demand Routing Algorithms in MANETs

Trung Kien Vu,Sungoh Kwon 한국통신학회 2014 한국통신학회 학술대회논문집 Vol.2014 No.6

Modeling of shunt active power filter using PSCAD/EMTDC

Trung-Kien Vu,Se-Jin Seong 전력전자학회 2009 전력전자학술대회 논문집 Vol.2009 No.2

In this paper, a shunt active power filter (SAPF) has been used to eliminate the harmonic distortion and to improve the power quality of three-phase grid-connected power conditioning system (PCS). The adopted control strategy in active power filter system is based on the instantaneous reactive power theory (P-Q theory). Based on the theoretical analysis, the overall system of three-phase grid-connected with non-linear load PCS has been built and modeled using PSCAD<SUP>®</SUP>?/EMTDC™. The simulation results are shown to verify the high effective performance of the implemented SAPF in power system and to verify the reasonableness of the system structure.

A New On-Line Dead-Time Compensator for Single-Phase PV Inverter

Trung-Kien Vu(부우충기엔),Hanju Cha(차한주) 전력전자학회 2010 전력전자학술대회 논문집 Vol.2010 No.7

This paper presents a new software-based on-line dead-time compensation technique for single-phase grid-connected photovoltaic (PV) inverter system. To improve the mitigation of dead-time effect around the zero-crossing point of phase current, a selective harmonic elimination of instantaneous feedback current is used as an additional part of conventional current control scheme. Simulation and experimental results are shown to verify the effectiveness of proposed compensation method in the gridconnected power distributed generation systems.

A Study about Output Filter of Paralleled Three-Phase Grid-Connected PV Inverters

Trung-Kien Vu 전력전자학회 2011 전력전자학술대회 논문집 Vol.2011 No.7

The rising popularity of renewable energy sources resulted in development of the units of higher rated powers. As a result of the limited power handling capacity of individual devices, paralleling is the choice to increase the equipment rating, while keeping the THD of the current at the PCC within the agency specified standards. And their typical power circuit configuration limits the stress on individual devices to an appreciable extent. The main scope of this paper is the analysis of filter structure in paralleling inverter system’s operation. Simulation results are shown to verify the theoretical analysis.

Mobility-Assisted on-Demand Routing Algorithm for MANETs in the Presence of Location Errors

Vu, Trung Kien,Kwon, Sungoh Hindawi Publishing Corporation 2014 The Scientific World Journal Vol.2014 No.-

<P>We propose a mobility-assisted on-demand routing algorithm for mobile ad hoc networks in the presence of location errors. Location awareness enables mobile nodes to predict their mobility and enhances routing performance by estimating link duration and selecting reliable routes. However, measured locations intrinsically include errors in measurement. Such errors degrade mobility prediction and have been ignored in previous work. To mitigate the impact of location errors on routing, we propose an on-demand routing algorithm taking into account location errors. To that end, we adopt the Kalman filter to estimate accurate locations and consider route confidence in discovering routes. Via simulations, we compare our algorithm and previous algorithms in various environments. Our proposed mobility prediction is robust to the location errors.</P>

Ultra-Reliable and Low Latency Communication in mmWave-Enabled Massive MIMO Networks

Trung Kien Vu,Chen-Feng Liu,Bennis, Mehdi,Debbah, Merouane,Latva-aho, Matti,Choong Seon Hong IEEE 2017 IEEE COMMUNICATIONS LETTERS Vol.21 No.9

<P>Ultra-reliability and low latency are two key components in 5G networks. In this letter, we investigate the problem of ultra-reliable and low-latency communication in millimeter wave-enabled massive multiple-input multiple-output networks. The problem is cast as a network utility maximization subject to probabilistic latency and reliability constraints. To solve this problem, we resort to the Lyapunov technique, whereby a utility-delay control approach is proposed, which adapts to channel variations and queue dynamics. Numerical results demonstrate that our proposed approach ensures reliable communication with a guaranteed probability of 99.99%, and reduces latency by 28.41% and 77.11% as compared to baselines with and without probabilistic latency constraints, respectively.</P>

Comparative Analysis of Input Filter for Single-Phase PV Inverter

Trung-Kien Vu,Se-Jin Seong 전력전자학회 2009 전력전자학술대회 논문집 Vol.2009 No.1

Nowadays, the LCL-filter type becomes an attractive grid interfacing for grid-connected Voltage Source Inverter(VSI) LCL-filter can render the current harmonics attenuation around the switching frequency by using smaller inductance than L-filter. Moreover, system using LCL-filter does not depend on the grid impedance and has a better output response while comparing with LC-filter. Firstly, an analysis and design procedure of output LCL-filter for single-phase grid-connected Photovoltaic(PV) inverter system is presented in this paper. Due to the theoretical analysis, a comparison between the designed LCL-filter with L-and LC-filter based single-phase grid-connected PV inverter system is carried out. The comparison results are given to validate the theoretical analysis and effectiveness of filters.

PR Controller Based Current Control Scheme for Single-Phase Inter-Connected PV Inverter

Trung-Kien Vu(부우충기엔),Se-Jin Seong(성세진) 한국산학기술학회 2009 한국산학기술학회논문지 Vol.10 No.12

최근 태양광 시스템에서는 기존의 태양광 시스템을 계통과 전원으로 상호 접속하는 것에 대한 연구에 관심 이 모아지고 있다. 단상, 삼상 시스템에 관계없이 태양광 시스템에서 태양광 인버터는 계통연계 동작에 중요한 역할 을 하기 때문에 전체 시스템에서 핵심요소로 고려된다. 태양광 인버터를 제어하기 위해서는 부하 전류 조절이 핵심요 소 중 하나이다. 일반적으로 태양광 인버터에서 이용되는 PI 제어기는 정상상태 오차와 왜란에 취약하다는 단점을 가 지고 있기 때문에 실제 시스템에 완벽하게 적용하기에는 무리가 있다. 특히, 이는 고주파영역에서의 PI와 PR 제어기 의 성능을 비교해보면 알 수 있다. 이 논문에서 제시된 PR 제어기는 무한 이득을 교류 기본파 성분에 넣을 수 있기 때문에 PR 제어기는 회전좌표계의 PI 제어기에서 사용되는 디커플링 기법과 복잡한 변환 없이 제로 정상상태오차에 도달할 수 있다. 그렇기 때문에 이 논문에서는 PI 제어기를 대체하는 이론적 분석을 통해 PR 제어기를 설계하였다. 논문에 제시되어 있는 이론을 바탕으로 한 PR 제어기를 고정 소수점 연산방식의 32비트 마이크로컨트롤러 DSP320F2812를 기반으로 한 3kW 프로토타입 태양광 인버터에 적용, 평가하였다. 또한 태양광 인버터의 제어 성능을 시뮬레이션과 실험결과를 통하여 보여주고 검증하였다. Nowadays, the PV systems have been focused on the interconnection between the power source and the grid. The PV inverter, either single-phase or three-phase, can be considered as the core of the whole system because of an important role in the grid-interconnecting operation. An important issue in the inverter control is the load current regulation. In the literature, the Proportional+Integral (PI) controller, normally used in the current-controlled Voltage Source Inverter (VSI), cannot be a satisfactory controller for an ac system because of the steady-sate error and the poor disturbance rejection, especially in high-frequency range. By comparison with the PI controller, the Proportional+Resonant (PR) controller can introduce an infinite gain at the fundamental ac frequency; hence can achieve the zero steady-state error without requiring the complex transformation and the dq-coupling technique. In this paper, a PR controller is designed and adopted for replacing the PI controller. Based on the theoretical analyses, the PR controller based control strategy is implemented in a 32-bit fixed-point TMS320F2812 DSP and evaluated in a 3kW experimental prototype Photovoltaic (PV) power conditioning system (PCS). Simulation and experimental results are shown to verify the performance of implemented control scheme in PV PCS.