Enrico Sangiorgi, DEI – UNIBO

1. Le tecnologie Elettroniche e Informatiche al servizio
della gestione energetica
Enrico Sangiorgi
“Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”
Workshop
Logo
azienda/università

2. “Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”
OUTLINE
• Smart grid and renewable energy sources
integration
• Smart buildings
• Power conversion
• Photovoltaic systems and overview of solar
cell technology

3. Smart Grid Scenario
Integration of
renewable energy
Energy efficient
transmission
EV charging and
energy storage
Smart metering
Energy efficient
consumption
Energy
efficient
consumption

4. “Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”
Energy to Smart Grid

5. “Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”
Outline
• Smart grid and renewable energy sources integration
• Smart building
• Power conversion
• Photovoltaic systems and overview of solar cell
technology

6. “Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”
Smart Building
• Distributed energy consumption profiler at building level with
integration of heterogeneous protocols
• Interactions with the central data processing unit in order to
elaborate energy consumption profiles at building level
building
level
network
floor/apartment network
(e.g. Zigbee, Bluetooth, etc.)
Connection
to building
level network
(e.g. Wi-fi,
PLC, etc.)

7. “Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”
Smart Metering and Local
Collection
• Miniaturized sensor system are used for
monitoring local power consumption
• Local collection (e.g. apartment level) of
power/energy consumption data through
a low-power IEEE802.15.4 wireless
network (e.g. Zigbee/Bluetooth/etc.
nodes).
• Bridge to an external higher level network
connection (e.g. Wi-Fi, or PowerLine
Communication) for transferring data at
building level.
floor/apartment network
(e.g. Zigbee, Bluetooth, etc.)
Connection
to building
level network
(e.g. Wi-fi,
PLC, etc.)

8. “Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”
Building Level Network
• A building level network collects
data from all local networks
through the bridge nodes
• Possible architectures for the
building network based on:
– Internet
– Power Line Communication
• All collected data transferred to a
server database. Profiles and
consumption data can be
extracted.
building
level
network

9. “Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”
Outline
• Smart grid and renewable energy sources integration
• Smart building
• Power conversion
• Photovoltaic systems and overview of solar cell
technology

10. “Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”
Power Converters
• Si-based power transistors (i.e. IGBT,
power MOSFET, Thyristor) are
implemented in converters for optimal
power transfer to the grid
• SiC FET or GaN HEMT allows to increase
BV with respect to Si devices because of
the higher bandgap. Alternatively, for a
given BV, a lower RDSON can be achieved.
ST AN3152 Application note
BV=600-650V
M. Trey et al., IEDM 2012

11. “Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”
Reliability of Power MOSFETs
An experimental setup has been implemented at University of Bologna
(Cesena Campus) in order to investigate the defectiveness of Power
MOSFETs provided by ST Microelectronics
10
-1
10
0
10
15
10
16
10
17
TrapDensity(cm
-3
eV
-1
)
Sample 1
Sample 2
Sample 3
|VGS
- VT
| (V)
Defects in the gate
oxide are evaluated by
means of noise
measurements. Such a
quantity is useful to
understand the
reliability of MOS
structure.Drain Contact
Gate Contact
Source Contact

12. “Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”
Outline
• Smart grid and renewable energy sources integration
• Smart building
• Power conversion
• Photovoltaic systems and overview of solar cell
technology

13. “Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”
Photovoltaic system

14. “Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”

15. “Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”
Silicon Solar Cells:
technology options overview
Interdigitated back contact (IBC)
S.Inoueetal.,23rdEUPVSEC(2008)J.Zhaoetal.,SolMAT,65,2001.
Passivated Emitter with Rear
Locally diffused (PERL)
Metal Wrap Through (MWT) Heterojunction with intrinsic thin layer (HIT)
Single junction silicon solar cells: theoretical max efficiency 33 %
η=20 % η=23 %
η=23 %η=25 %
Imec,BE

16. “Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”
Multijunction Solar Cells
http://www.laserfocusworld.com
• Multi-junction solar cells or tandem cells are solar cells
containing several p-n junctions.
• Each junction is tuned to a different wavelength of light.
• Efficiency above 40 %

17. “Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”
Thin Film Solar Cells
http://www.sneresearch.com
• Cell thickness 0.5 – 5 μm
• Low cost
• Efficiency < 10 % (commercial device)
• Flexible substrates
• Photovoltaic integrated into the building

18. “Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”
Thin Film Solar Cells:
photon management
Nanoparticle-enhanced
amorphous-silicon solar cell
W.-ShingKohandY.Akimov,SPIE2010
http://scitechdaily.com
Erik C. Garnett et al., Annu. Rev. Mater. Res. 2011. 41:11.1–11.27
Photonic Crystals
Nanowire-based solar cells

19. “Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”
Research goals at
device/module level
• Lowering cost-per-watt of solar cell/modules
– Investigation of new materials, architectural options,
frabrication processes
– Optimization of cell design
– New light trapping strategies
– Optimization of contacting schemes
• Investigation of device reliability and variability
• Modeling of solar cells/modules
– Feedback to industry and photovoltaic community to
address new technologies and fabrication options

20. “Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”
Simulation of PV solar cell
• Modeling by numerical simulation at device level
Optimization of light absorptance
in vertical nanowires
Optimization of the geometry of a
PERL solar cell

21. “Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”
Simulation at Cell/Module level
• Cell/Module level simulation can be used to investigate:
– the impact of non-uniformity on the conversion efficiency
(e.g. partial shadowing, local shunting)
– System reliability (e.g. study of temperature increase in
the solar cell)
0.515 V
0.550 V
0.530 V
15.6 cm
Potential distribution along solar cell
Local temperature transient in silicon
solar cells (a comparison between
experimental data and simulations)

22. “Ridurre i costi energetici in azienda: dagli scenari ai meccanismi di incentivazione”
22
Facilities at Cesena Campus
• Solar Simulator Abet Sun 2000 (Class A Spectral
Match)
• Test station for contacting 156mm x 156mm solar cells,
with temperature control.
• 4 SMU Keithley (2600 series) for IV measurement of
solar cells (up to 12A)
• Semi-automatic probe station 200mm (Cascade) with
thermal chuck (from -55°C to 200°C) for wafer
measurements
• 4 SMU for static characterization
• Agilent 81110A Pulse Generator
• Agilent E4980A LCR meter (2MHz)