EES-UETP Microgrid course

DC MICROGRIDS

MicroGr dRESEARCH

PROGRAMME

Prof. Josep M. GuerreroMicrogrid Research Programme – Aalborg University

www.microgrids.et.aau.dk [email protected] 7-06-2014

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Outline

Microgrid Research Programme – ET – AAU

Microgrid Research Programme in AAU

Microgrid Definition and Operation

Microgrids Projects

DC Microgrid Control Architectures

Denmark Grid Concept

Microgrid Research Programme – ET – AAU 3

Smart grid in Denmark – Hourly pricing


Residential Microgrids - 2013 DK Smart Grid Strategy

(2015 hourly electricity pricing)

Hydrogen Communities (Vestenkov, Lolland) – IRD Small remote/isolated Microgrids

Large remote Microgrids:

Geographical islands

(70 habited islands in DK)

Microgrid technologies applications in Denmark

Potential areas


Programme Purpose

MicroGrid Research Programme Areas

AC MicroGrids

DC MicroGrids

Modeling

Control & Operation

Energy Storage

Protection

Power Quality

Standard-based ICT

Networked Control

EMS & Optimization

Multi-Agents

MICROGRID RESEARCH PROGRAMME

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Figures:6 Post Docs12 PhDs5 Visiting scholars

MICROGRID RESEARCH TEAMMICROGRID RESEARCH TEAM @ AALBORGPhDs

P. Coordinators

Josep M. Guerrero

Post DocsTomislav DragicevicDC MGs

Fabio AndradeMGs stability

Qobad ShafieeSecondary Control

Lexuan MengTertiary Control

Dan WuPrimary Control

Chendan LiMGsAgents

Yajuan GuanAncillary services for MGs

Nelson DiazEnergy storage for MicroGrids

Chi ZhangLVDC distribution MGs

Hengwei LinManagement and Protection for Microgrids

Xin ZhaoAC/DC Hybrid MG

Bo SunEV Charging Stations

PhD GuestsJavier RoldanLVRT & PQ

Valerio MarianiNonlinear Control

Ernane CoelhoMGs modelling

Juan C. Vasquez

Visiting Prof.Min ChenPower Electronics

Yang HanPQ & MV MGs

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AAU Intelligent MicroGrid Laboratory

Every setup is able to emulate a multi-converter low-voltage Microgrid, local and energy management control programmed in real-time control platforms.

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Every setup is able to emulate a multi-converter low-voltage Microgrid, local and energy management control programmed in real-time control platforms.MGCC Labview, communication systems, control, 24 DC-AC inverters


EthernetCommunication

DC Power Line

AC Power Line

10 10Microgrid Research Programme – ET – AAU

The laboratory is based on 6 workstations• 4 DC-AC converters,• LCL-filters, • ABB Motorized change-over switches • Kamstrup Smart-meters.


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Microgrid Central Controller

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Kontor Kontor Målerum Justerrum EDB

Kontor

Kontor

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Kontor

Lab. for relæ- Sluse

Bad

Teknik/reng.

Anlægslab.

Højspændingshal

Kontrolrum

Lab.

Teknik

Opstilling

El-værksted

VVS-værksted

teknik

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Lager

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teknik

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ET Intelligent MicroGrid Laboratory13 15 17 19 21

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Kontrolrum

Lab.

Teknik

Opstilling

El-værksted

VVS-værksted

teknik

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Kontor

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Lab.

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El-værksted

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teknik

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Handicapindgang

Bidirectional pow

er supply

ElectricPanelboard

Workstation 4

DC power lineAC power line SmartMeters

Cabinet

Workstation 3

Wor

ksta

tion

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ksta

tion

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Workstation 2

Workstation 1

Communication Nodes

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Outline




Microgrids Projects


General aspects of a MicroGrid: “Definition and Operation”

What is a Microgrid? Renewable Energy Resources

Main Utility Grid

Compressed Air System

Electric Vehicles

PCC

Batteries

Household appliances and electronics

PV

EV

Flywheel

Power Electronics

PV

WT

IBS

DC Coupled Subsystem

PV

Hybrid AC/DC Microgrids

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Intelligent DC Microgrid Living Lab

i-DClab

MicroGr dResearch

Programme

DSF Sino-Danish project 2014-2017

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15Microgrid Research Programme – ET – AAU

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PV

DC Homes living lab

WT

New iDC Laboratory - iDClab

AC line DC line

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Phase I: Design, modelling and control. Phase II: Coordination control schemes between microgrid elements, including

communication systems and energy management systems for DC microgrids. Phase III: Creation of two Living Labs as a user-centred research concept, to test

innovation systems and elements that can conform a DC microgrid for different applications.

• Home DC Microgrid Living Lab, at AAU to research and test DC distribution for 1-2 family houses

• 工业微网设计 Industrial DC Microgrid Living Lab, At North China Electrical Power University (China), for research, demo and test of energy solutions for commercial buildings.

Intelligent DC Microgrid Living Lab


Future Residential LVDC Power Distribution Architectures

MicroGr dResearch

Programme

DFF project 2014-2016

International ranked research institutions And the Danish Companies

18MicroGrid Research programme: www.microgrids.et.aau.dk

http://www.ritsumei.ac.jp/se2012/re/ee/eng/faculty/


This project will be done in cooperation with:

International ranked research institutions

And the Danish Companies

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http://www.ritsumei.ac.jp/se2012/re/ee/eng/faculty/


Phase 1. Design, modelling and controlPhase 2. Coordination and control of power electronic units connected to the DC busPhase 3. Grid integration and interactivity

380Vdc Powered Home

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380Vdc Powered Home

1. Vdc consumer electronics2. 12/24 Vdc wall sockets3. 12 Vdc LED lighting4. 24 Vdc home entertainment system5. 12 Vdc coffee maker6. 12 Vdc refrigerator7. 24 Vdc vacuum cleaner8. 48 Vdc washing machine9. 48 Vdc air conditioner10. 12 Vdc hair dryer11. 48 Vdc whisper wind turbine12. PVs connected in 380vdc bus bar13. 380vdc charger14. 380vdc busway distribution system

Flexible electric vehicle charging infrastructure Flex –ChEV

MicroGr dResearch

Programme

ERANET project 2014-2016

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Functionalities of the EVCS

P/Q coordinationFrequency participationVoltage supportUnbalance compensationHarmonics sharing



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Outline




Microgrids Projects


DC Distribution Microgrids


Advantage of DC transmission systems no reactive power loading of the transmission line complete control of energy flow no reactive power loading of the transmission line reduced losses

Why Back to Back links? Different system frequencies No additional short circuit power contribution to connected networks Fully controllable power flow



Problems in AC microgrids: Synchronization of distributed generators Inrush current (transformers, Induction motors, Induction generators) Three-Phase Unbalance (single-phase loads, single-phase generators such as

photovoltaic)

Recent Trends Introduction of many Inverter loads (AC/DC and DC/AC conversions are included) Introduction of distributed generations with DC output (photovoltaic, fuel

cell,variablespeed type wind turbine, microturbine, gas engine) Needs for higher quality power

DC-Coupled Microgrids DC microgrids/nanogrids DC distributed power systems (DPS) Applications: VRM, -48 V telecom systems, DC-link for UPS systems Isolated systems: avionic, automotive, marine…



300-400V DC Operational and Demo Sites Worldwide (Europe, USA and Japan)

Demonstrations of 300-400V DC MicroGrids in the world



AC Residential system

AC commercial system

DC Microgrid topology



The key application areas for standardization of dc power use in buildings include:

✔Interiors and occupied spaces where lighting and control loads dominate the need for dc electricity✔Data centers and telecom central offices with their dc powered information and communications technology (ICT ) equipment✔Outdoor electrical uses, including electric vehicle charging and outdoor light-emitting diode (LED ) lighting✔Building services, utilities, and HVAC with variable-speed drive (VSD ) and electronic dc motorizedequipment.

24 VDC 380 VDC

380 VDC 24 & 380 VDC



EMerge Alliance dc standard as implemented for building interiorsDC 24V- Infrastructure



EA’s dc standards as implemented in a data center



Barriers: The Challenges of Increased DC Use in Buildings

The use of dc power is not without it challenges. These fall into 5 major categories:1) lack of application and equipment standards for dc power distribution2) lack of common understanding and basic application knowledge of building distribution-level dc3) differences in safety and power protection device application4) lack of a robust ecosystem to support the use of dc in building-level electrification5) unclear pathway for moving from ac-centric power distribution to dc-inclusive distribution schemes.

The first 3 challenges are being addressed with increasing resources by such standards and trade organizations as:

EA , the European Telecommunications Standards Institute (ETSI ), the International Electrotechnical Commission (IEC ), IEEE , NE MA, NFPA, the Power Sources Manufacturers Association (PSMA), the Smart Grid Interoperability Panel (SGI P) of the National Institute of Standards and Technology (NIST ), UL , and others.



DC Microgrid at Xiamen University, China 150 kWp PV System DC Lighting Energy Storage Air Conditioning Electric Vehicle Charge Station Data Center Home And Office Appliances

Cloud-based energy monitor, management, and control system Optimal equipment choice and operation of direct-current MicroGridsEfficiency Comparison: DC vs. AC Lighting: 92% vs.78% AC: 93%vs. 87% Data Center: 78% vs.64% EV Charger: 94% vs.76%


DC Homes

DC Building (EPARC, Taiwan) DC 380 V 150 kWp PV System DC Lighting Energy Storage Air Conditioning Electric Vehicle Charge Station Data Center Home And Office Appliances

Cloud-based energy monitor, management, and control systemOptimal equipment choice and operation of direct-current microgrids

Efficiency Comparison: DC vs. AC Lighting: 92% vs.78% AC: 93%vs. 87% Data Center: 78% vs.64% EV Charger: 94% vs.76%


DC Homes

DC Building (EPARC, Taiwan) DC 380 V


DC Homes

Green Home (Korea) DC 380 V

LVDC 380 V MV Distribution level 22.9 kV


DC Homes

Fukuoka Smart House DC 380 V (Japan)

Home Energy Management Systems

Bidirectional Meters


Data server


DC microgrids for data centers & servers

Four power conversions can result in a poor efficiency of the system. Online UPS system is easily available in the market

Supplying digital loads. A classical solution:



PDU -. Power Distribution Unit. PSU -. Power Supply Unit

DC microgrids for data centers & servers



Example of distributed power architecture

Source: Intechopen

PIBC PBUS PPOL

IBC



Typical AC distribution architecture (dotted components are optional)

Commercial UPS system solution Two AC buses (AC main & critical AC bus) High number of conversions (until 5)

Source: Leonardo Energy


DC Distribution MicrogridsTypical DC distribution architecture

Front ends are used

High voltage DC bus

Low number of conversions




DC distribution architecture with intermediate bus

Intermediate low voltage bus




Small scale demonstration comparing conventional a high efficiency AC architecture (on right) with 380V DC facility-level distribution (on left). Overhead lights operated on 380Vdc as well.

DC – AC Demonstration Facility



Small scale demonstration setup for AC (top) and DC (bottom)7% improved efficiency and 6% savings with DC

DC – AC Demonstration Facility



Sendai Microgrid Project









Fukushima



Fukushima



Events timeline for a microgrid in Sendai, Japan, after the March 11, 2011 earthquake.

K. Hirose, “Performance of the Sendai Microgrid During the 2011 Earthquake and Tsunami”



DC Homes

Japan residential DC microgrid


DC Microgrid Ring (Japan)




REbus™ is an open standard for DC electricity distribution. REbus™ microgrid is a flexible energy network that lets you make and use clean renewable energy for home, business, school, or neighbourhood. (400V)

Comercial DC Microgrid



Primary Source Units (PSU)

Load Units (LU) Powerline Communication

• Robust narrowband FSK modulation• Programmable transmission data rate up to 30kbps• Programmable communication frequency from50kHz to 500kHz• Complete Media Access Control (MAC) logic• CSMA/CD type collision detection and resolution• Programmable automatic preamble generation• Programmable automatic packet-prioritymanagement with four levels• Error detection (CRC 16) REbus™

Comercial DC microgrid

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Shifting Concepts from AC to DC Microgrids

f/V Droop Control Resistive line P-V droopResistive virtual impedance Virtual inertia f-PVirtual synchronous gen

DC droopP-V droop

I-V virtual resistanceDC inertia V-P

Virtual dynamo

www.microgrids.et.aau.dk 58

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Typical configuration of a DC Microgrid

59 59www.microgrids.et.aau.dk

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Microgrids Research

COORDINATED CONTROL FOR ISLANDED MICROGRIDS

DC Low voltage MicroGrid coordinated control:

DC Microgrids: Bus voltage signaling

www.microgrids.et.aau.dk

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Hierarchical Control for DC-Microgrids

PRIMARY CONTROL OF A DC MicroGrid


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SECONDARY CONTROL OF A DC MicroGrid


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PHiL Results

Microgrids Research

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TERTIARY CONTROL AND EMS IN MicroGrids


DC System Optimization ---- Local Generation Control

Typical Efficiency Curve

Problem Formulation Constraints

• Capacity• DC Bus Voltage• System Dynamics

Objective• System Overall Efficiency

Output Current (A)

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Microgrids Research


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Adaptive VR

System Damping

System efficiency

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Microgrids Research


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The research is based on droop controlled paralleled dc-dc converters.

In primary control level, adaptive virtual resistance method is proposed and

implemented for changing the load sharing ratio among converters.

Secondary control for system damping is proposed to achieve desirable system

damping level when tertiary control shifts virtual resistance.

Tertiary control for system efficiency optimization is proposed and

demonstrated to be capable of improving system level efficiency.

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Conclusion



Centralized Optimization Method

Primary

Primary

Secondary

Tertiary

Communication Links

Central ControllerAdv.: 1. Reliable solution2. Strong supervision3. Easy implementation.

Dis-Adv.: 1. Failure on comm. and central controller

may cause the failure of the whole system2. Low flexibility and expandability3. Not suitable for sighly distributed system.

Obstacle of Distributed Optimization:Optimization requires reliable global information

Solution: Consensus Algorithm

Multiagent Systems for DC-Microgrids


Tertiary Agent based Distributed Hierarchical Control



DC System Optimization ---- Local Generation Control


Study Case


Multi-agent Based Distributed Optimization

#1

#2

#3

#4



Complete control architecture



Conclusion Consensus algorithm is used for distributed information sharing

Genetic Algorithm is implemented in tertiary level for obtaining optimal

output current of each converter considering the operation sequence of

each converter

Virtual resistance is adjusted so as to follow the optimal current reference

given by tertiary control

Simulation results demonstrate the effectiveness of the method, however,

the system stability considering the impact of communication and

consensus algorithm need to be further analyzed


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Dragicevic, Tomislav; Pandžić, Hrvoje; Škrlec, Davor; Kuzle, Igor; Guerrero, Josep M.; Kirschen, Daniel ” Capacity Optimization of Renewable Energy Sources and Battery Storage in an Autonomous Telecommunication Facility.I E E E Transactions on Sustainable Energy, 2014.

Dragicevic, Tomislav; Shafiee, Qobad; Wu, Dan; Meng, Lexuan; Vasquez, Juan Carlos; Guerrero, Josep M. / Modeling and Control of Flexible HEV Charging Station upgraded with Flywheel Energy Storage.Proceedings of the 11th International Multi-Conference on Systems, Signals and Devices, SSD 2014. IEEE Press, 2014.

El Fadil, Hassan; Giri, Fouad; Guerrero, Josep M. / Modeling and Nonlinear Control of Fuel Cell / Supercapacitor Hybrid Energy Storage System for Electric Vehicles.In: I E E E Transactions on Vehicular Technology, 2014.

Dragicevic, Tomislav; Vasquez, Juan Carlos; Guerrero, Josep M.; Skrlec, Davor / Advanced LVDC Electrical Power Architectures and Microgrids : A Step towards a New Generation of Power Distribution Networks.In: I E E E Electrification Magazine, Vol. 2, No. 1, 03.2014, p. 54-65 .

Dragicevic, Tomislav; Guerrero, Josep M.; Sucic, Stepjan / Flywheel-Based Distributed Bus Signalling Strategy for the Public Fast Charging Station. In: I E E E Transactions on Smart Grid, 2014.

Gouveia, C.; Moreira, C.L.; Lopes, J.A.P., "Microgrids emergency management exploiting EV, demand response and energy storage units," PowerTech (POWERTECH), 2013 IEEE Grenoble , vol., no., pp.1,6, 16-20 June 2013

J.A. Peças Lopes, Silvan A. Polenz, C.L. Moreira, Rachid Cherkaoui, Identification of control and management strategies for LV unbalanced microgrids with plugged-in electric vehicles, Electric Power Systems Research, Volume 80, Issue 8, August 2010, Pages 898-906.

References DC Microgrids

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MicroGrids Courses

Oct. 14 – Oct. 152013

Nov. 26 – Nov. 272013 Oct. 16 – Oct. 17

2013

Oct. 28 – Oct. 302013

Industrial/PhD course on EMS and Optimization in

Microgrids - In Theory and Practice



Microgrid research and activities

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Thank you for your attention!

Juan C. Vasquez [email protected] M. Guerrero [email protected]

MicroGr dRESEARCH

PROGRAMME

www.microgrids.aau.dk


Engineering

EES-UETP Microgrid course