Ruralgrid project

Carles Jaen

Carme Hervada

13/05/2014

Feasibility study in order to introduce renewable energies by

means of microgrids in the Pyrenees' Area

• What’s a microgrid?• Ruralgrid project objectives• Partners/Organization• Social Committee. Members and tasks• Technological Committee. Members and tasks• Transfer Committee. Members and tasks• Environmental Committee. Members and tasks• Bibliography• Conclusion

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What’s a microgrid?

http://vimeo.com/15778505

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Ruralgrid project objectives

• The main goal is to define, design and implement smart control

systems allowing a real time regulation and applied to electrical

energy microgrid located in the Pyrenees rural area.

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Partners

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Partners: Aquitaine

Project code: 11011568‐11011572

• Ecole Supérieure des Technologies Industrielles Avancées (ESTIA)

•Laboratoire de l’Intégration du Matériau au Système (IMS)

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Partners: Aragón

Project code: CTPP14/11

• Escuela de Ingeniería Informática de Universidad San Jorge.

• Instrumentación y componentes (INYCOM)

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Josep Pou Dr. Enginyer industrial Convertidors de potència, energies renovables, transmissióHVDC

Gabriel Capellà Enginyer industrialParal·lelització de convertidors de potència

Antoni Arias Dr. Enginyer industrialSistemes de velocitat variable, convertidors de potència

Carles Jaén Dr. Enginyer industrialSistemes fotovoltaics, seguidors solars

Jordi Zaragoza Dr. Automàtica i electrònica industrialConvertidors de control de potència

Carme Hervada Dra. en FísicaFísica mediambiental i geoestadística

Ricard Picas Enginyer en Automàtica i Electrònica IndustrialConvertidors de potència multinivell

Partners: Euskadi

Project code: CTP11/P7

•Applied Electronics Research Team (APERT)

•Tecnalia

•Jema Energy S.A.

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Partners: Midi Pyrenées

Project code: 11051384

•Ecole Nationale d'Ingénieurs de Tarbes (ENIT)

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Organization

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ENITUSJ

EHU- TECNALIA-JEMAUPC

INYCOMESTIAENITUSJ

INYCOM ESTIA-IMS-LOREKIENITUSJ UPC

Social committee• Tasks:

– 21 Agenda. • The 21 Program is a United Nations agreement in order to promote the

sustainable development.. It was approved in The United Nations Conference about the Environment and Development, held in Rio deJaneiro on June 1992

– Opinion poll

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Technological Committee• Tasks:

– To contribute to have a feasible generation based on microgrids

– To optimize the transmitted signal quality– To improve the control techniques and the parallelizing

techniques of power generators– The microgrid will share synchronised converters to

deliver their maximum power and achieving an stabilized signal.

– The remainder power should be distributed to the main grid

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Transfer Committee• Tasks:

– Show that the microgrids are economically feasible

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Environmental Committee• Tasks:

– State of the art analysis:• Characterizing of commercial low power generators (especial

emphasis on renewable energies).– Compromise between energy generation and environmental

impact: • Definition of energetic needs of a rural area town in order to

improve the energetic efficiency and introduce new technologies.

• Adjust the power generation to the climate, land and economy of the selected rural town.

– Make a simulation:• Design a microgrid devoted to the optimization of the

energetic resources in a rural town located in the Pyrenees.

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Architecture of the microgrid

DC TransmissionArchitecture

Power converters in the microgrid and energy transmission

Variability of renewable sources

Potential for active load control

Bidireccional power flow

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Power parallel converters DC/DC boost optimization

Scheme

Experimental platform

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A new method to improve the total efficiencyof parallel converters

Block diagram

Experimental platform

The proposed methodology takes into account the individual efficiency curves and determines the optimum operating point for each converter such that the maximum efficiency of the arrangement is achieved for the entire load range.

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Modular Multilevel Converter (MMC)

Scheme

• The MMC is a VSC-based multilevel topology• Its principal feature is modularity, which provides

scalability, reliability and compatibility with commercial semiconductors.

• Nowadays is the principal candidate for high voltage direct current (HVDC) transmission systems.

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Paralleling legs

The parallel connection of inverter legs is a way to increase the output currents and thus the converter rated power

The connection is usually made by inductors and a critical issue is to achieve balanced currents among the legs.

Circulating currents produce additional losses and stress to the power devices of the converter. Therefore, they should be controlled and minimized.

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InductorsParalleled legs of a VSI cannot be directly connected.

Inductors qualify for:

Averaging the voltage from several legs.

Limiting the circulating currents among the legs.

Improving the output voltage spectrum.

Inductors can be magnetically coupled or uncoupled.

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IndividualReferencesGenerator

PWM n legsPhase a

s

aj

TLi ⋅Δ

−

aREFv

Overmodulation Preventer

...

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dcV

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2/1

dcV

L

LocalAverager

S & H (Ts)

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......

230 0.005 0.01 0.015 0.02

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-300

-200

-100

0

100

200

300

400

( ) ( )aj ajs

Lv k i kT

Δ = − Δ

Equivalent output voltage(3 parallel legs)

Phase-a n paralleled legs

Current balance control scheme

Experimental

results

Current balancing strategy for interleaved voltage source inverters

Parallel-Connected Legs in a Grid-Tied Inverter System

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08-30

-20

-10

0

10

20

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Time, t (s)

Cur

rent

s (A

)

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0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08-40

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Three-Phase Three-leg inverter

Voltage oriented control (VOC)

Legs & phase-a currents.Grid voltages.Reactive current reference change.

Leg currents and phase currents.

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Single carrier modulator for interleaved PWM

Block diagram

Experimental results

Load

Inductors

Inverter

Powersupply

Dspace1103

interface

Sensor board

DC capacitors

Experimental platform

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• Sant Pau de Segúries (Ripollès)– Inhabitants 699 (2008)

‐ Nowadays operative

hydropower plant

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• Optimization software

• Many technological solutions and their feasibility.

• Allows for different generators, batteries and also grid connection.

Simulation program: Homer Energy Software 

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Microgrid (hydropower) connected to main grid (actual)

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Hybrid micro grid (hydro-solar) Connected to main grid

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- Comparative actual to hybrid

Hybrid configuration allows for a spare of 1% of main gridconsumption

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• Rivert(Conca d’Allà‐ Pallars Jussà)– Inhabitants 31 (2013)

‐ Planning to build a hydropower

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Ruralgrid project team

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Publications

• R. Picas, J. Pou, S. Ceballos, V. G. Agelidis and M. Saeedifard. “Minimization of the

Capacitor Voltage Fluctuations of a Modular Multilevel Converter by Circulating

Current Control”. 38th Annual Conference on IEEE Industrial Electronics Society,

Montréal, Canada, 2012, pp. 4985-4991.

• Arias, A.; Ortega, C.; Zaragoza, J.; Espina, J.; Pou, J. “ Hybrid sensorless permanent

magnet synchronous machine four quadrant drive based on direct matrix converter”

International Journal on Electrical Power and Energy Systems. Elsevier, 2013, 45, 78-

86.

• R. Picas, J. Pou, S. Ceballos, J. Zaragoza, G. Konstantinou and V. G. Agelidis,

“Optimal Injection of Harmonics in Circulating Currents of Modular Multilevel

Converters for Capacitor Voltage Ripple Minimization”. IEEE International Energy

Conversion Congress and Exhibition for the Asia/Pacific region (ECCE Asia),

Melbourne, Australia, 2013

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Publications

• R. Picas, S. Ceballos, J. Pou, J. Zaragoza, G. Konstantinou, and V. G. Agelidis,

“Improving Capacitor Voltage Ripples and Power Losses of Modular Multilevel

Converters through Discontinuous Modulation”. 39th Annual Conference on

IEEE Industrial Electronics Society, Vienna, Austria, 2013.

• F. H. Dupont, J. Zaragoza, C. Rech and J. R. Pinheiro,” A simple control strategy

to increase the total efficienfy of multi-converter systems”. 12th Brazilian Power

Electronics Conference (COBEP2013).

• F. H. Dupont, J. Zaragoza, C. Rech and J.R.Pinheiro,” A new method to improve

the total efficienfy of parallel converters”. 12th Brazilian Power Electronics

Conference (COBEP2013).

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Publications

• Arias, A.; Rain, X.; Hilairet, M.” Enhancing the flux estimation based sensorless

speed control for switched reluctance machines.” Electric Power Systems Research

Journal.,2013, 104, 62-70

• R. Darus, J. Pou, G. Konstantinou, S. Ceballos, and V. G. Agelidis, "A modified

voltage balancing sorting algorithm for the modular multilevel converter: Evaluation

for staircase and phase-disposition PWM," accepted in IEEE Applied Power

Electronics Conference and Exposition (APEC), Fort Worth, TX, USA, 16-20 March

2014.

• G. J. Capella, I. Gabiola, J. Pou, J. Zaragoza, S. Ceballos, and V. G. Agelidis,

"Minimum signal modulation scheme based on a single carrier for interleaved

operation of parallel phase legs in voltage source converters," accepted in IET Power

Electronics.

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