1. Professor Sung-Yeul Park
Battery Energy Storage with an Inverter that Mimics Synchronous Generators
Team 1508 Members
Nerian Kulla
Sabahudin Lalic
David Hooper
Faculty Advisor
Professor Sung-Yeul Park
To: ECE/CSE Faculty
ECE 4901
Design Review
11/11/2014

2. Outline Background Information Project Goals Key Specifications Design
DC/DC Design
DC/AC Design
Final Integrated Design
Budget
Time line

3. Background Information
IFEC, which stands for International Future Energy Challenge, is an international student competition for innovation, conservation, and effective use of Electrical Energy.
The main objective of this project  is to:
develop a grid-connected energy storage system with an inverter that can mimic the functions of synchronous generators.
able to autonomously deliver the right amount of real power and reactive power according to the grid frequency and voltage or
to regulate the frequency and voltage via changing the real power and reactive power delivered.

4. Design a Battery that will supply Power to a vehicle, as well as a Power Grid.
Battery capability:
Bi-directional current flow
(Grid to Battery or Battery to Grid)
Potentially fulfill the energy storage needs of the electric
grid supplying ancillary services
reactive power compensation
voltage regulation
and peak shaving

5. Project Goals
Realize power conversion between the battery and the gird/load with high efficiency
Achieve seamless transfer between grid-connected and stand-alone modes
Reduce manufacturing cost
Have the basic functions of charging,
discharging and protection for the battery
Meet the desired power quality to the grid/load
Improve power density

6. Key Specifications

7. Design Requirements/Challenges: Needs to be bidirectional
It requires to Buck and Boost the voltage
Convert voltage from DC to AC
Convert voltage from AC to DC
Be within the budget
Be energy-efficient
Meet the specifications

8. Topology DC-DC Converter Bidirectional Buck & Boost converters
Buck converter required to lower voltage from 350V DC to 48V DC
Boost converter required to increase the voltage from 48V DC to 350V DC
Uses a LC filter to conduct buck and boost conversion and regulate voltage/current ripple

9. Topology AC-DC Rectifier Rectifier Bridge
Convert AC-to-DC needed to charge battery
Input 230V AC and outputs 325V DC
Uses diodes to rectify current from AC to DC
Uses Inductor to filter current ripple
A DC link Capacitor filter voltage ripple

10. DC-AC Inverter/AC-DC Rectifier
Topology
DC-AC Inverter/AC-DC Rectifier
Inverter Bridge
Convert DC-to-AC
Uses four Power MOSFET switches
PWM to control the MOSFET
LC filter for a clean B2G AC waveform

11. Topology Power Schematic Bidirectional Boost Converter
(Battery to Grid )
&
Buck Converter
(Grid to Battery)
AC-to-DC (Grid to Battery)
&
DC-to-AC (Battery to Grid)
DC Link

12. Devices Switching Devices Sensors Inductors Transformer Capacitors
IGBT, MOSFET, GaN, etc.
Sensors
Current sensor, Voltage sensor
Inductors
Transformer
Capacitors

13. Devices
Switches
Active switches are used to invert DC to AC and convert DC to DC for buck and boost mode using PWM
- Devices considered were the MOSFET, IGBT and GaN

14. Devices Switches The device of choice is the Power MOSFET
High switching frequency ( >200kHZ)
Reduces the size of the passive elements i.e. Inductors, Capacitors
Low switching power loss
Low conduction resistance
Low cost

15. Devices Sensors Current Sensors Voltage Sensors
Measure the input current and output current
Needed for the control stage
Voltage Sensors
Measure the AC Grid voltage, DC Link voltage and Battery voltage.
Needed to for feedback for the control stage

16. PCB Board
Using Altium Designer software, we plan on designing our PCB board using the Top and Bottom layer for the components, as well as a mid-layers for common connections, reduce noise levels, and for High Current usage. (Power, Ground, etc.)
When building a PCB board, there are different things to consider for the most efficient, safest and reliable Power usage.

17. Placing Components
We give careful thought when placing components in order to minimize trace lengths.
We place Parts next to each other that connect to each other, which will make laying out traces less difficult and more neat.
Arrange components in a specific orientation (up and down, left and right) for easier Pin connections.

18. Using complete planes for Power, Ground, etc.
Copper pours on signal layers are common in PCB’s:
Can be a hatched ground pour an analog design
Solid Power supply pour for carrying heavy currents
Solid ground pour for EMC shielding

19. Track Design
Determine standard track width ( avoid shorts occurring, number of tracks used in an area)
Consider track size for lines carrying current
Determine pad shapes and sizes
Thermal Issues
With higher processing speeds and higher component densities, in addition working with high voltages and currents, thermal issues should be taken into consideration
It is important to allow sufficient space for cooling around hot components.
It is also a good idea to leave extra space around components that dissipate larger amounts of heat.

20. Timeline Completed: Proposal submission System Simulations
Circuit Schematic/Design
Future Goals:
PCB Layout
Qualification Report
Performance Test

21. Timeline Completed: Proposal submission System Simulations
Circuit Schematic/Design
Future Goals:
PCB Layout
Qualification Report
Performance Test

22. Budget

23. Questions?