DC Fast Charging -Where do we Stand? 1.72 3.29 3.34 3.98 4.59 4.84 5.01 5.26 6.16 7.13 7.16 8.99...

DC Fast Charging - Where do we Stand?

Dr. Arindam Maitra, EPRI

EVS 27, Barcelona, SpainNovember 18, 2013

2© 2013 Electric Power Research Institute, Inc. All rights reserved.

Organized by Hosted by In collaboration with Supported by

Public Charging May Address “Range Anxiety”

• Fast charging requires high power

• Unique challenges in terms of infrastructure, operational cost due to demand charges

• Creating a sustainable business case will require economics that match utilization.

• Simple and convenient solution has potential to strengthen range confidence; address psychological “barrier”

• Planned in coordination with home and work place charging solutions in region

• Potential to increase traffic for some retail locations



Market for DCFC is Small & Location Dependent

• Most energy is still likely to be transferred at home

• Location is everything – I-5 San Diego/LA corridor DCFC sees heavy traffic

• Consumers are willing to pay (on average) between $10-20/charge

0

20

40

60

80

100

120

11-2 11-22

Total Energy per Day

(kWh)

Total Energy

Consumption for

1 Month: 1,034

kWh

Friday

before

Thanksg

iving



DC Fast Charge Connectors in US

CHAdeMO

SAE Combo

Tesla



Current Status of DC Fast Charging in US

• Public DC fast charger deployments in the North America:

– CHAdeMO: A DC charging protocol developed and adopted as a standard in Japan; limited to approximately 50kW

– Tesla Supercharger: a proprietary protocol developed by Tesla Motors; 120kW

• Approximately 200 CHAdeMO chargers deployed in the US

• Tesla has deployed eight Supercharger stations in the US, some with multiple fast chargers, with plans to deploy more than two dozen additional stations by late 2013

• Products that include the US Standard SAE Combo connector are expected by the end of 2013

– Chevy Spark and BMW i3 are first vehicles expected to use Combo



31%

37%

41%

42%

48%

51%

51%

52%

53%

59%

60%

70%

72%

77%

Places of worship

Coffee shops

Fitness centers

Sporting Venues

Government offices/buildings

On street, metered parking

Hospitals

Entertainment locations

Restaurants

Grocery stores

Airports

Shopping centers/malls

Public parking garage

At your place of work

Preferred Charging Locations*

Plug-In Hybrid

Version

(n=509)

Battery-Only Version

(n=499)

* Preferred charging locations are based on 3-hour charging for the Plug-In Hybrid Version and 8-hour charging for the Battery-Only Version.

Charging Preferences

34%

32%

40%

35%

47%

50%

40%

49%

45%

52%

52%

66%

61%

77%



Charge Profiles using Eaton 50KW Charger

0

10,000

20,000

30,000

40,000

50,000

60,000

0 5 10 15 20 25 30 35

Po

we

r (W

att

s)

Time (min)

Charge Profiles Pac (Leaf) Pac (iMieV)

0

10,000

20,000

30,000

40,000

50,000

60,000

0 5 10 15 20 25 30 35

Po

we

r (W

att

s)

Time (min)

Charge Profiles Pac (Leaf) Pac (iMieV)

Starting Battery Empty

Eac(Leaf) = 21.28KWh Eac(Leaf) = 13.15KWh Eac(Leaf) = 8.14KWh

Eac(iMieV) = 10.47KWh Eac(iMieV) = 4.16KWh Eac(iMieV) = 6.30KWh

Eac(Leaf) = 21.28KWh Eac(Leaf) = 13.15KWh Eac(Leaf) = 8.14KWh

Eac(iMieV) = 10.47KWh Eac(iMieV) = 4.16KWh Eac(iMieV) = 6.30KWh



Effect of Starting Battery Capacities on Charge Profile

0

10000

20000

30000

40000

50000

60000

0 5 10 15 20 25 30 35 40

Pa

c (W

att

s)

Minutes

Leaf Charge Profiles for Various Starting Battery Capacities

0 kWh starting battery capacity 13.6 kWh starting battery capacity

16.4 kWh starting battery capacity 17.2 kWh starting battery capacity

0

10000

20000

30000

40000

50000

60000

0 5 10 15 20 25 30 35 40

Pa

c (W

att

s)

Minutes

Leaf Charge Profiles for Various Starting Battery Capacities

0 kWh starting battery capacity 13.6 kWh starting battery capacity

16.4 kWh starting battery capacity 17.2 kWh starting battery capacity

TOTAL

Pac (Pdc)

CC MODE

Pac

CV MODE

Pac

0khwr 21.28 (19.18) 13.15 8.14

13.6kwhr 8.62 (7.52) 1.30 7.32

16.4kwhr 5.98 (5.13) 0.33 5.65

17.2kwhr 4.38 (3.67) 4.38



SOC Profiles under Different Command Currents

0

10

20

30

40

50

60

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

DC

Po

we

r (K

W)

State of Charge

Power (120A) kW Power (100A) kW Power (80A) kW

Power (60A) kW Power (Eaton 125A)



Starting Battery Capacity

– DC Fast Charging versus 240V Charging

� 240V charging ends at 101 min

� Energy charged using 240V is more than DCFC charging (~ 5.93 kWh)

� 240V charging ends at 165 min

� Total energy charged is same for both DCFC and 240V



Harmonics vs Power

0%

2%

4%

6%

8%

10%

12%

14%

16%

18%

1.7

2

3.2

9

3.3

4

3.9

8

4.5

9

4.8

4

5.0

1

5.2

6

6.1

6

7.1

3

7.1

6

8.9

9

9.3

9

9.9

0

11

.35

13

.08

13

.68

15

.82

18

.86

21

.91

44

.73

%

Pac (W)

Ic Harmonic Magnitude (% of Fundamental)

3rd 5th 7th

Harmonic spectrum indicates 3rd harmonic –possibly a single phase ancillary load



What Applications Make Sense?

• Business Models, customer needs, and utilization

• Low utilization Level – Economics of low-utilization sites will be dominated by capital costs for equipment installation and demand charges

• Intermediate utilization Level – Intermediate-utilization charging happens once fast charging demand at one location is high enough that multiple ports can be profitably installed and total charging capacity can be shared between number of vehicles at once

• High utilization Level – High-utilization charging occurs once charging is common enough that fast charging is a customer expectation. This level will also support multi ports and controlled charging of number of vehicles at once

0

20

40

60

80

100

120

11

/3/2

01

2

11

/5/2

01

2

11

/7/2

01

2

11

/9/2

01

2

11

/11

/20

12

11

/13

/20

12

11

/15

/20

12

11

/17

/20

12

11

/19

/20

12

11

/21

/20

12

11

/23

/20

12

11

/25

/20

12

11

/27

/20

12

11

/29

/20

12

12

/1/2

01

2

12

/3/2

01

2

12

/5/2

01

2

25 KW Fuji Electric

Energy (kWh)



Intelligent Universal Transformer (IUT) – a Paradigm

Shift

Intelligent Universal

Transformer (IUT™)Distribution

Transformer



Medium-Voltage IUT Based DC 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

• IUT Direct DC 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

LV AFE

AC /DC

iso lated

DC/DC

Medium vo ltage util ity grid

Conventional t ransformer

××××3

Building wire

××××3

CHAdeMOconnector

(a) Conventional DC fast charge r with low-voltage powe r

electronics

(b) EPRI DC fast charger with me dium-voltage IUT

LV AFE

AC /DC

iso lated

DC/DC

Medium vo ltage util ity grid

Conventional t ransformer

××××3

Building wire

××××3

CHAdeMOconnector

(a) Conventional DC fast charge r with low-voltage powe r

electronics

(b) EPRI DC fast charger with me dium-voltage IUT



Configuration of Medium Voltage Fast Charger

M-level AFEAC-DC &Isolated DC-DC

DC-DC

Charger

400-V DC

2.4 or8 kV AC +

–

1. Multilevel active-front-end (AFE) converter is located at service entrance

2. AC input can be interrupted with high-voltage 12-kV vacuum switch

3. Low-voltage DC distribution system serves the charging station

4. DC voltage can be interrupted with a DC circuit breaker

5. Charger output is Chademo compatible



Utility Direct Fast Charger with CHAdeMO Interface

DSP

board

Medium

Voltage

DC-DC

Charger

Vehicle

Side

Battery

Management

System

Interface

PC Display

Control

Console

1,7

2

4

GND

d1

d2

RDY

8

9

10

CAN+

CAN–

5555

6666

PWR+

PWR–

IrefVrefCMD

2.4kV

rms



2.4KV 50kW Medium Voltage IUT Based DC Charger –

Efficiency Comparisons

86%

88%

90%

92%

94%

96%

98%

100%

30% 40% 50% 60% 70% 80% 90% 100%

% E

ffic

ien

cy

% Load

Efficiency vs Power (as % of Full Load)

200V Commercial FC 200V Commercial FC + Conventional Transformer

Overall 2.4KV IUT FC 2.4KV AFE Converter Efficiency

86%

88%

90%

92%

94%

96%

98%

100%

30% 40% 50% 60% 70% 80% 90% 100%

% E

ffic

ien

cy

% Load

Efficiency vs Power (as % of Full Load)

200V Commercial FC 200V Commercial FC + Conventional Transformer

Overall 2.4KV IUT FC 2.4KV AFE Converter Efficiency



Summary of IUT – DC Fast Charging Application

• Can be less expensive than current 208/480 VAC DC fast chargers

• Significantly lower installation costs

• More flexible operation—integrate on-site renewables and storage

• Can manage multiple charging connectors and standards seamlessly

• The IUT can be a utility-owned asset and a third party can manage the ‘service station’ portion

• Next steps

– Public demonstration of field-ready, certified unit (hopefully in 2014)

DC Fast Charging -Where do we Stand? 1.72 3.29 3.34 3.98 4.59 4.84 5.01 5.26 6.16 7.13 7.16 8.99...

Documents

Transcript of DC Fast Charging -Where do we Stand? 1.72 3.29 3.34 3.98 4.59 4.84 5.01 5.26 6.16 7.13 7.16 8.99...