European cooperation Network on Energy Transition in Electricity

RobertoPrietoCEIUPM- CenterforIndustrialElectronicsofUPM

SESSION2:SMARTGRIDSCHALLENGES:THEVISIONOFTECHNOLOGICALCENTRES

WORKSHOP“DEFININGSMARTGRIDS:CONDITIONSFORSUCCESSFULIMPLEMENTATION”

Barcelona,9thFebruary2017

▪ Hierarchicalarchitecture▪ Powerconvertersasinterfaces

¢ Energy Control Center (ECC)¢ Individual power supplies¢ Bus providers

▪ Distributedgeneration¢ Renewable sources¢ Traditional generators

▪ Energystoragesystems▪ SmartGrid

Microgrid

µ-ECC

Utilitymains

Nanogridn-ECC

Picogrid

p-ECC

▪ DCnativeloadsandsources¢ Photovoltaic, batteries, fuel cells…¢ Consumer electronics, LED lighting

▪ Centralpowerfactorcorrector¢ Less conversion stages at device level¢ No need for AC/DC power adapters

▪ Simplersmallerconverterinterfaces¢ No need for synchronization¢ Less components: no rectification¢ No need for low frequency bulk capacitors

in each power supply

▪ DCcurrentdisconnection¢ Reliable DC circuit breakers¢ Plugs and sockets

▪ Busesandwiring¢ Lack of reliable standard¢ How many voltage levels do we need?

▪ Droopcontrolandhierarchicalcontrol¢ Distributed control and communication network¢ Implementation in converter controller loop

▪ Energymanagement¢ Energy storage and distributed generators¢ Islanding and grid connection¢ Power converters are essential for energy flows

» Imagesource:Nextek PowerSystems&EMerge Alliance

▪ 3φ – 380VDCn-ECC▪ 380Vdistribution▪ LVDCroompicogrids

¢ Safe voltage level¢ Limited power¢ Internal bus¢ Channel distribution

▪ PHEVpicogrid¢ Smart battery

management

▪ Bidirectionalconverters¢ Enhanced flexibility

n-ECC

p-ECC

p-ECC

Picogrid2LVDC

Picogrid1PHEV

Nanogrid380V

Internalbus

▪ Maindistributionbus– 380VDCnanogrid¢ Widely used in datacenters¢ Low wire losses¢ Supplies high power equipment and p-ECC¢ High power distributed generation and bulk energy storage

▪ PHEVbus¢ Follows PHEV charging standards¢ High power, medium voltage, short bus

▪ LVDCbuses¢ Voltages yet to be determined¢ Internal medium voltage bus¢ Power distribution through extra low voltage, low power independent

channels¢ Consumer electronics, LED lighting, low power generation…

Design

Model

Simulation

Satisfactory?

No

Implementation

Satisfactory?

No

Yes

Nanogrid

Others

Controlsystem

Powerconverters

▪ Offtheshelf– Internal architecture

unknown– Difficult to find models

Black-boxmodelling

Ensure stability

Grid

AC/DC

DC/DC

AC/DC

DC/DC

DC/AC

DC/DC

DC/DC

DC/DCDC/DC

DC/DCDC/DC

DC/DC

𝑉"#$ = 380V

𝑉"#$ = 48V 𝑉"#$ = 24V 𝑉"#$ = 12V

Grid

???

?

?

?

?

?

?

?

??

𝑉"#$ = 380V

𝑉"#$ = 48V 𝑉"#$ = 24V 𝑉"#$ = 12V

DCbussignalingVoltagedroopcontrol

Grid converter Batteries Renewable sources

∆𝑉

∆𝐼 ∆𝐼 ∆𝐼

Lineal

• G-parametersmodel

• Linealormildy non-linealsystems

Wiener-Hammerstein

• Non-linealstaticbehavior

• Linealdynamics

Polytopic

• Non-linealsystems• Trade-offbetweenaccuracyandcomplexity

Black-boxmodelling

Non-Linearstatic

behavior

u yInputLineal

dynamic

OutputLineal

dynamic

u y

StudiedDCnanogrid

Blackbox polytopic model

Droopcontrol

Droopcontrol

Doublecontrolloopwithcurrentlimitation

Droop

Current sharing

StudiedDCnanogrid

Blackbox polytopic model

Droopcontrol

Droopcontrol

Doublecontrolloopwithcurrentlimitation

Operation mode change

Loaddisconnection

StudiedDCnanogrid

Blackbox polytopic model

Droopcontrol

Droopcontrol

Doublecontrolloopwithcurrentlimitation

Voltage restoration