• Title, Summary, Keyword: Distributed DC power system

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A Distributed Control Method based on Voltage Sensitivity Matrix in DC Microgrids for Improvement of Power Sharing Accuracy and Voltage Regulation Performance (직류 마이크로그리드의 전력 공유 정확도 및 전압 제어 성능 향상을 위한 전압 민감도 행렬 기반의 분산 제어 방법)

  • Lee, Gi-Young;Ko, Byoung-Sun;Lee, Jae-Suk;Kim, Rae-Young
    • The Transactions of the Korean Institute of Power Electronics
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    • v.23 no.5
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    • pp.345-351
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    • 2018
  • A distributed control method is proposed to improve the power sharing performance of bidirectional distributed generators and the voltage regulation performance of a DC bus in a DC microgrid. Voltage sensitivity analysis based on power flow analysis is conducted to analyze the structural characteristics of a DC microgrid. A distributed control method using a voltage sensitivity matrix is proposed on the basis of this analysis. The proposed method uses information received through the communication system and performs the droop gain variation method and voltage shift method without additional PI controllers. This approach achieves improved power sharing and voltage regulation performance without output transient states. The proposed method is implemented through a laboratory-scaled experimental system consisting of two bidirectional distributed generators, namely, a load and a non-dispatchable distributed generator in a four-bus ring-type model. The experimental results show improved power sharing accuracy and voltage regulation performance.

A Study of the Active Resonance Damper for a DC Distributed Power System with Parallel Pulsed Power Loads (병렬펄스부하를 갖는 직류배전시스템을 위한 능동 공진 댐퍼에 대한 연구)

  • La, Jae-Du;Lee, Byung-Hun;Chang, Han-Sol;Woo, Hyun-Min;Kim, Young-Seok
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.9
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    • pp.1289-1295
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    • 2012
  • An active resonance damper for a DC Distributed Power System(DPS) with parallel loads is presented. Each pulse power load in a DC DPS comprises both a resistive power load and a step-up converter. The step-up converter behave as constant power load(CPL) when tightly regulated and usually cause a negative impedance instability problem. Furthermore, when an input filter is connected to a large constant power load, the instability of DC bus voltage. In this paper, a bidirectional DC/DC converter with a reduced storage capacitor quantitatively are proposed as a active resonance damper, to mitigate the voltage instability on the bus. The validity of the proposed method was confirmed by simulation and experimental works.

Optimized Design and Coordinated Control for Stand-alone DC Micro-grid (독립형 DC 마이크로그리드의 최적화 설계와 협조적 제어)

  • Han, Tae-Hee;Lee, Ji-Heon;Kim, Hyun-Jun;Han, Byung-Moon
    • The Transactions of the Korean Institute of Power Electronics
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    • v.18 no.1
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    • pp.63-71
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    • 2013
  • This paper describes the coordinated droop control method for stand-alone type DC micro-grid to improve reliability and utilization of distributed generations and energy storage. The stand-alone type DC micro-grid consists of several distributed generations such as a wind power generation, solar power and micro-turbine, and energy storage. The proposed method which is based on autonomous control method shows high reliability and stability through coordinated droop control of distributed generations and energy storage and also capability of battery management. The operation of stand-alone type DC micro-grid was analyzed using detail simulation model with PSCAD/EMTDC software. Based on simulation results, a hardware simulator was built and tested with commercially available components and performance of system was verified.

Grid-Tied and Stand-Alone Operation of Distributed Generation Modules Aggregated by Cascaded Boost Converters

  • Noroozian, Reza;Gharehpetian, Gevorg;Abedi, Mehrdad;Mahmoodi, Mishel
    • Journal of Power Electronics
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    • v.10 no.1
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    • pp.97-105
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    • 2010
  • This paper presents the modeling, control and simulation of an interconnection system (ICS) of cascaded distributed generation (DG) modules for both grid-tied and stand-alone operations. The overall configuration of the interconnection system is given. The interconnection system consists of a cascaded DC/DC boost converters and a DC/AC inverter. Detailed modeling of the interconnection system incorporating a cascaded architecture has not been considered in previous research. In this paper, suitable control systems for the cascaded architecture of power electronic converters in an interconnection system have been studied and modeled in detail. A novel control system for DC/DC boost converters is presented based on a droop voltage controller. Also, a novel control strategy for DC/AC inverters based on the average large signal model to control the aggregated DG modules under both grid-tied and stand-alone modes is demonstrated. Simulation results indicate the effectiveness of the proposed control systems.

Premium Power Quality Using Combination of Microturbine Unit and DC Distribution System

  • Noroozian, Reza;Abedi, Mehrdad;Gharehpetian, Gevorg
    • Journal of Electrical Engineering and Technology
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    • v.5 no.1
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    • pp.103-115
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    • 2010
  • This paper discusses a DC distribution system which has been supplied by external AC systems as well as local microturbine distributed generation system in order to demonstrate an overall solution to power quality issue. Based on the dynamic model of the converter, a design procedure has been presented. In this paper, the power flow control in DC distribution system has been achieved by network converters. A suitable control strategy for these converters has been proposed, too. They have DC voltage droop regulator and novel instantaneous power regulation scheme. Also, a novel control system has been proposed for MT converter. Several case studies have been studied and the simulation results show that DC distribution system including microturbine unit can provide the premium power quality using proposed methods.

A Design of a PI Compensator for a Bidirectional DC-DC Converter in a DC Distributed Power System

  • Lee, Joonmin;Seok, Bong Jun;La, Jae Du;Kim, Young Seok
    • Journal of international Conference on Electrical Machines and Systems
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    • v.1 no.3
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    • pp.391-396
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    • 2012
  • The Voltage Bus Conditioner(VBC) is a bidirectional DC-DC converter for damping the instability and any transients of the bus voltage in a DC Distributed Power System(DPS). In this paper, a PI controller for the VBC has been designed for the frequency domain. The proposed PI controller not only dampens the bus transients, but also keeps the storage voltage level. Simulation by Matlab/Simulink and experimental results are presented for the validity of the proposed control technique.

Capacity Optimizing method of Distributed Generators in Stand-Alone Microgrid Considering Grid Link-Characteristics

  • Han, Soo-Kyeong;Choi, Hyeong-Jin;Cho, Soo-Hwan
    • Journal of Electrical Engineering and Technology
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    • v.13 no.4
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    • pp.1483-1493
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    • 2018
  • Recently, more power facilities are needed to cope with the increasing electric demand. However, the additional construction of generators, transmission and distribution installations is not easy because of environmental problems and citizen's complaints. Under this circumstance, a microgrid system with distributed renewable resources emerges as an alternative of the traditional power systems. Moreover, the configuration of power system changes with more DC loads and more DC installations. This paper is written to introduce an idea of a genetic algorithm-based solution to determine the optimal capacity of the distributed generators depending on the types of system configuration: AC-link, DC-link and Hybrid-link types. In this paper, photovoltaic, wind turbine, energy storage system and diesel generator are considered as distributed generators and the feasibility of the proposed algorithm is verified by comparing the calculated capacity of each distributed resource with HOMER simulation results for 3 types of system configuration.

Operation Analysis of a Communication-Based DC Micro-Grid Using a Hardware Simulator

  • Lee, Ji-Heon;Kim, Hyun-Jun;Han, Byung-Moon
    • Journal of Power Electronics
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    • v.13 no.2
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    • pp.313-321
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    • 2013
  • This paper describes the operation analysis results of a communication-based DC micro-grid using a hardware simulator developed in the lab. The developed hardware simulator is composed of distributed generation devices such as wind power, photovoltaic power and fuel cells, and energy storage devices such as super-capacitors and batteries. Whole system monitoring and control was implemented using a personal computer. The power management scheme was implemented in a main controller based on a TMS320F28335 chip. The main controller is connected with the local controller in each of the distributed generator and energy storage devices through the communication link based on a CAN or an IEC61850. The operation analysis results using the developed hardware simulator confirm the ability of the DC micro-grid to supply the electric power to end users.

Characteristics of High Efficiency DC/DC Converter for Self-Dr Synchronous Retifier (자기구동 동기정류를 위한 고효율 DC/DC컨버터의 특성비교)

  • Yoon, Suk-Ho;Moon, Gun-Woo;Yoon, Jong-Soo;Kim, Yong
    • Proceedings of the KIEE Conference
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    • pp.1973-1976
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    • 1998
  • Recently, new trend in telecommunication device is to apply low voltage, about 3.3V-1.5V. However, it is undesirable in view of high efficiency and power desity which is the most important requirement in the distributed power system. Rectification loss in the output stage, in on-board converter for distributed power system are constrained to obtain high efficience at low output voltage power suppies. This paper explains the basic operational principles of three kinds of ZVS DC/DC converters with self-driven synchronous rectifier. The three topologies are analyzed by simulation and exprimentation, and the characteristics comparisons of high efficience converter are carried out in view of the minimized rectification losses in the out stage.

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A Positioning Method of Distributed Power System by Considering Characteristics of Droop Control in a DC Microgrid

  • Ko, Byoung-Sun;Lee, Gi-Young;Kim, Sang-Il;Kim, Rae-Young;Cho, Jin-Tae;Kim, Ju-Yong
    • Journal of Electrical Engineering and Technology
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    • v.13 no.2
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    • pp.620-630
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    • 2018
  • In this paper, a positioning method of distributed power system is proposed to minimize the average voltage variation of a DC microgrid through voltage sensitivity analysis. The voltage sensitivity under a droop control depends on the position of the distributed power system. In order to acquire a precise voltage sensitivity under a droop control, we analyzed the power flow by introducing a droop bus with the considerations of the droop characteristics. The results of the positioning method are verified through PSCAD/EMTDC simulation.