1. 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
𝐼 𝜑 = 𝑙𝑖𝑛𝑒 − 𝑡𝑜 − 𝑙𝑖𝑛𝑒 𝑐𝑢𝑟𝑟𝑒𝑛𝑡 = 32𝐴 (due to use of wye connection)
𝑘𝑉𝐴 = (𝑉𝜑 𝐼 𝜑) 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