We’d like to thank the Department of Sustainable Technologies, and especially our mentor, Michael

Villaran, for their support throughout our project. We’d also like to thank BNL’s Office of Educational

Programs, especially Noel Blackburn, Mike Stegman, Sal Gonzalez, and Cindi Biancarosa for their

support throughout our project.

This project was supported in part by the New York State Collegiate Science and Technology Entry

Program (CSTEP) at Fordham University and Suffolk County Community College under the CSTEP-

Supplemental Undergraduate Research Program (SURP) at Brookhaven National Laboratory.

This project was also supported in part by the National Science Foundation, Louis Stokes Alliance(s) for

Minority Participation (LSAMP) at Syracuse University under the LSAMP Internship Program at

Brookhaven National Laboratory.

Yao Aleke, CSTEP intern, Department of Engineering Science, Suffolk County Community College, Selden, NY 11784

Rebecca Borrero, CSTEP intern, Department of Physics & Engineering Physics, Fordham University, Bronx, NY 10458

Raul Martinez, NSF/LSAMP intern, Department of Electrical & Computer Engineering, Syracuse University, Syracuse, NY 13210

Michael Villaran, program mentor, Department of Sustainable Energy Technologies, Brookhaven National Laboratory, Upton, NY 11973

One of Brookhaven National Lab’s (BNL) many research facilities is the Northeast Solar Energy

Research Center (NSERC), which is a 1-MW photovoltaic (PV) research facility, with approximately 518

kW of potential capacity currently installed. It is currently used to test integration of high penetrations of

solar energy into electrical distribution systems, while future plans include testing a wide range of new

PV technologies. The most significant problem with renewable energy is that the energy supply is

variable (as shown at right in Figure 1), and it rarely matches demand. This problem can be solved by

storing energy when the energy supply is greater than demand, and drawing from storage when

demand is greater than energy supply. Our project uses the concept of vehicle-to-grid (V2G) technology

(using car batteries for grid support) to deal with this storage deficiency.

[1] BNL | NSERC, the Northeast Solar Energy Research Center http://www.bnl.gov/energy/images/solar-

array-940px.jpg

[2] ChargePoint CT4000 Data Sheet, 2013. http://www.chargepoint.com/files/CT4000-Data-Sheet.pdf

[3] Ying Fan, Zhongbing Xue, and Xuedong Han, “Bi-directional Converting Technique for Vehicle to Grid,”

presented at the International Conference on Electrical Machines and Systems, Beijing, China, 2011.

We designed a V2G system, shown above, that integrates NSERC’s solar grid with three dual

electric vehicle charging stations that work with electric vehicles the lab already owns. The vehicles will

store energy when NSERC’s supply is greater than demand and distribute it back to BNL’s grid when

the demand is higher than NSERC’s supply. Due to the difficulties we encountered in finding a V2G-

capable charging station, we designed our V2G system to include cost-effective modifications to BNL’s

existing EVs to make them V2G-compatible and still work with standard charging stations. A possible

configuration to be done inside the car is shown below in Figure 6. Application of this research would

support the Department of Energy’s mission by contributing to our nation’s energy security, and make

the long-term goal of sustainable energy production more realistic by putting an energy storage solution

within reach. Future work will include inspection by BNL safety authorities, installation of the V2G

system, collection and analysis of data relating to V2G capabilities of BNL’s EV fleet, and eventually

expansion of the system.

Transformer:

Primary voltage = 480V, Secondary voltage = 208V

𝑉𝜑 =𝑙𝑖𝑛𝑒 − 𝑡𝑜 − 𝑙𝑖𝑛𝑒 𝑣𝑜𝑙𝑡𝑎𝑔𝑒

3=

208𝑉

3= 120𝑉

𝐼𝜑 = 𝑙𝑖𝑛𝑒 − 𝑡𝑜 − 𝑙𝑖𝑛𝑒 𝑐𝑢𝑟𝑟𝑒𝑛𝑡 = 32𝐴 (due to use of wye connection)

𝑘𝑉𝐴 = (𝑉𝜑𝐼𝜑) 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑝ℎ𝑎𝑠𝑒𝑠 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑠𝑡𝑎𝑡𝑖𝑜𝑛𝑠

𝑘𝑉𝐴 = 120𝑉 32𝐴 3 6 = 70𝑘𝑉𝐴

We rounded up to the next standard size, 75 kVA.

Disconnect (at 480V):

𝑃𝑟𝑖𝑚𝑎𝑟𝑦 𝑐𝑢𝑟𝑟𝑒𝑛𝑡 (𝑓𝑜𝑟 𝑤𝑖𝑟𝑒 𝑟𝑎𝑡𝑖𝑛𝑔) = 75𝑘𝑉𝐴

(𝑝𝑟𝑖𝑚𝑎𝑟𝑦 𝑉𝜑)(3)(6)=

75𝑘𝑉𝐴

480𝑉

3(3)(6)

= 15A

Assuming 150% max load gives us 22.5A. We rounded up to 30A for safety.

𝐷𝑖𝑠𝑐𝑜𝑛𝑛𝑒𝑐𝑡 𝑟𝑎𝑡𝑖𝑛𝑔 = 15𝐴 2 = 30𝐴

Assuming 150% max load gives us 45A.

Distribution panel (at 208V):

𝑇𝑜𝑡𝑎𝑙 𝑐𝑢𝑟𝑟𝑒𝑛𝑡 = 𝑐𝑢𝑟𝑟𝑒𝑛𝑡 𝑡ℎ𝑟𝑜𝑢𝑔ℎ 𝑒𝑎𝑐ℎ 𝑐ℎ𝑎𝑟𝑔𝑒𝑟 × 6 = 32𝐴 × 6 = 192𝐴

Assuming 150% max load gives us 288A. We rounded up to 300A for safety.

𝑆𝑒𝑐𝑜𝑛𝑑𝑎𝑟𝑦 𝑐𝑢𝑟𝑟𝑒𝑛𝑡 (𝑓𝑜𝑟 𝑤𝑖𝑟𝑒 𝑟𝑎𝑡𝑖𝑛𝑔) = 75𝑘𝑉𝐴

(𝑝𝑟𝑖𝑚𝑎𝑟𝑦 𝑉𝜑)(3)(6)=

75𝑘𝑉𝐴

208𝑉

3(3)(6)

= 35A

Assuming 150% max load gives us 52.5A. We rounded up to 60A for safety.

We began by researching how V2G systems operate,

in order to become familiar with the various parts needed to

create a V2G system. This included analyzing the existing

conditions in the substation that we will be using to power

the charging stations, finding a V2G-compatible charging

system, and figuring out how to make an electric vehicle

(EV) compatible with such a system. We then determined

the sizes, types, prices and ratings of the necessary

components, as well as their physical locations.

Figure 6: The proposed circuit topology for V2G. The

grid-side converter changes AC to DC using the PWM

Rectifier. The battery-side converter controls the DC

voltage using the buck converter going to the battery. The

boost converter increases the DC voltage, and finally the

grid-side converter uses the PWM inverter changes DC

to AC. The protection circuit in the middle provides

overflow protection: in case of current surges, it shuts

down the system and sends the energy back to the grid.3

Figure 1: NSERC power quality

data for June 24, 2014

Figure 2: Solar panels at the Northeast Solar Energy Research Center (NSERC)1

Figure 4: ChargePoint

CT4021 Bollard charging

station2

ABSTRACT DESIGN

ANALYSIS

CONCLUSIONS

REFERENCES

ACKNOWLEDGEMENTS

Figure 5: EV owned by the lab

Figure 3: Interconnection in Substation 521

between NSERC and charging stations

Using Brookhaven National Laboratory’s Electric

Vehicle Fleet As Grid Support