epri’s utility direct dc fast charger – development, testing,...

Arindam MaitraIWC Meeting

March 28, 2012

EPRI’s Utility Direct DC Fast Charger –Development, Testing, Demonstration

2© 2012 Electric Power Research Institute, Inc. All rights reserved.

Utility Direct “Medium Voltage” Fast Charger

• Conventional DC Fast Charger needs a new three-phase service

– Three-phase transformer– Three primary conductors and

associated medium voltage fuses– Three high-current service conductors– 208/480 Vac DC fast charger– Overall efficiency (w xfmr) ~88-91%– Installation costs

• Utility Direct Fast Charger

– Combines service transformer and DC fast charger into one unit

– Needs only one primary conductor, no isolation transformer and no secondary conductors

– Overall efficiency >95%– Installation costs


Configuration of Utility Direct Fast Charger

M-level AFEAC-DC &Isolated DC-DC

DC-DC

Charger400-V

DC

2.4 or8 kV AC +

–

• HV components are enclosed within thepad-mounted enclosure

• AC input can be interrupted with high-voltage vacuum switch

• DC voltage can be interrupted with a DCcircuit breaker

• Charger output is Chademo compatible


Pad-Mount Case for Medium-Voltage AFE Converter and Isolated DC-DC Stage (Box-A)

Photograph of the case and internal circuits


Utility Direct Fast Charger with CHAdeMOInterface

DSP

board

Medium

Voltage

DC-DC

Charger

Vehicle

Side

Battery

Management

System

Interface

PC Display

Control

Console

1,7

2

4

GNDd1

d2

RDY

8

9

10

CAN+CAN–

5

6

PWR+

PWR–

IrefVref

CMD

2.4kV

rms


2.4KV 50kW Medium Voltage IUT Based DC Charger –Efficiency Comparisons


EPRI Web/Mobile Application

CAN Listener

EPRI Server

Charger

Android Tablet

• Provides user interface to the charger

• Sends DC charging data to the EPRI Server

Bluetooth

Instrumentation

2.4 kV AC

500 VDC

CAN Bus

AC Charging Data

DC Charging

Data


Demo in Knoxville @March 6-7, 2012

• Medium Voltage IUT DC Fast Charger

– Fully functional 1-phase 2.4KV 45KVA IUT DC Fast charger (FC) system with the CHAdeMOcommunication protocols (CAN)

• Why is it valuable?– Utility owned asset for fast charging– Provide customers with a variety of

products and services that go “beyond the meter”

– Reduced energy losses versus conventional chargers

– Reduced weight versus fast chargers using conventional transformers


Installation Options

• Conventional FC installation

– Option 1: Underground installation (pad-mount)

– Option 2: Overhead installation (pole-mount)

• Medium Voltage FC installation (pad-mount)

The objective is to compare cost of installing a 480 Vac fast charger vs an EPRI MV fast charger


480 Vac Fast Charger vs MV Fast Charger Installations

480 Vac Fast Charger Installation – Option 1 480 Vac Fast Charger Installation – Option 2

Medium Voltage Fast Charger Installation


Key Installation Components

480 Vac FC (Option 1) 480 Vac FC (Option 2) EPRI MVDC FC3 long primaries (135 ft) 3 short primaries (5 ft) 1 long primary (135ft)1 three-phase 75 kVA pad-mount xfmr (13.8 kV/480 Vac)

3 single-phase 25 kVA pole-mount xfmrs(7.32kv/277 Vac)

-

Excavation, foundation, concrete pad, MV terminations

- -

4 underground service conductors (10ft) + 2underground DC service conductors (10 ft)

4 overhead service conductors (110 ft) + 2underground DC service conductors (10 ft)

2 underground DC service conductors (10 ft)

Trenching, conduits Some trenching, conduits Trenching, conduits

480 Vac service panel+ Secondary side metering

480 Vac service panel+ Secondary side metering

Primary side metering


Installation Cost

480 Vac FC (Option 1)

480 Vac FC (Option 2)

EPRI MVDC FC

Primaries $3937 $261 $1399

Transformer(s) $14776 $3638

Service conductor $752 $2284 $378

Service Panel $350 $350

Metering $365 $365 $1500

Foundation Cost for FC Main Box $3272 $3272 $3272

Total Cost $23452 $10170 $6549

* Approximate costs – these do not include unit price of the fast charger


Where this Technology Makes Sense

• Utilities who want to provide fast charging capability directly from their distribution system. This could be especially useful in dense cities where you place fast chargers that aren't hosted by a business

• Businesses could install Intelligent Universal Transformer (IUT) technology, as their building transformer and conveniently add fast charging service (and also integrate their onsite solar, energy storage, and building energy management system). This would help in managing the high peak loads of the DC charger and the impact both on the utility and to a business' own cost of service, specifically by reducing demand charges

• DC fast charging technology has the potential to significantly increase the range and versatility of battery electric vehicles, enhancing their commercial appeal


TVA iMieV CHARGING (Charging Event #1)March 6th, 2012


Charging Power as a Function of Time – iMieV

Time (minute)

Cha

rgin

g P

ower

(kW

)


Battery Capacitor and State-of-Charge – iMieV

Time (minute)

Bat

tery

Cap

acity

(kW

h)

Sta

te o

f Cha

rge SOC


Voltage and Current During Charging – iMieV

Time (minute)

Bat

tery

Vol

tage

(V)

Cha

rgin

g cu

rrent

(A)


EPRI LEAF CHARGING – Charging Event #2 March 6th, 2012


Charging Power as a Function of Time – Leaf

Time (minute)

Cha

rgin

g P

ower

(kW

)


Battery Capacitor and State-of-Charge – Leaf

Time (minute)

Bat

tery

Cap

acity

(kW

h)

Sta

te o

f Cha

rge


Voltage and Current During Charing – Leaf

Time (minute)

Bat

tery

Vol

tage

(V)

Cha

rgin

g cu

rrent

(A)


EPRI LEAF CHARGING – Charging Event #3 March 6th, 2012


Charging Power as a Function of Time – Leaf

Time (minute)

Cha

rgin

g P

ower

(kW

)


Battery Capacitor and State-of-Charge – Leaf

Time (minute)

Bat

tery

Cap

acity

(kW

h)

Sta

te o

f Cha

rge SOC

kWh


Voltage and Current During Charing – LeafB

atte

ry V

olta

ge (V

)C

harg

ing

curre

nt (A

)

Time (minute)


EPRI LEAF CHARGING – Charging Event #4

March 7th, 2012


Charging Power as a Function of Time – EPRI Leaf

Time (minute)

Cha

rgin

g P

ower

(kW

)


Battery Capacitor and State-of-Charge – EPRI Leaf

Time (minute)

Bat

tery

Cap

acity

(kW

h)

Sta

te o

f Cha

rge SOC

kWh


Voltage and Current During Charging – EPRI Leaf

Bat

tery

Vol

tage

(V)

Cha

rgin

g cu

rrent

(A)

Time (minute)


LEAF CHARGING – Charging Event #5 March 7th, 2012


Charging Power as a Function of Time – TVA Leaf

Time (minute)

Bat

tery

Cap

acity

(kW

h)

Sta

te o

f Cha

rge

SOC

kWh


Charging Power as a Function of Time – TVA Leaf

Time (minute)

Cha

rgin

g P

ower

(kW

)


Voltage and Current During Charging - TVAB

atte

ry V

olta

ge (V

)C

harg

ing

curre

nt (A

)

Time (minute)


Together…Shaping the Future of Electricity

epri’s utility direct dc fast charger – development, testing,...

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