A hybrid energy system performance

1. A Hybrid Energy
System
Performance
PVG & FCG interconnected to an AC main’s.
- Pranav Contractor, Assistant Professor, BITS - Vadodara

2. Why ?
• We know that surrounding weather and environmental conditions
change will result in Renewable energy resources suffer from the
lack of providing constant power.
• As a solution, storage batteries are traditionally employed in parallel
with the renewable energy resources and that is to supply any
deficiency or to absorb any excess in load energy requirements.
• Unfortunately, the storage batteries are characterized by an
additional considerable cost to renewable energy resources cost and
moreover, the storage batteries have also a short life time when
compared to the life time of the renewable energy resources.
• A wise solution to overcome the problem is relying totally on the
power generated only by the renewable energy resources is to
constitute a hybrid DC grid that should contain or connect
renewable energy resources and storage units in parallel and
interconnecting such hybrid DC grid to the AC grid through the
conventional power inverter modules.

3. • Advantage is that, at any time of operation and for any energy
load demand the energy is guarantied from the DC grid as well
as from the AC grid.
• Note that it will be nice to use the AC grid whenever there is
deficiency in energy from the hybrid DC grid.
• The ultimate goal of the proposed solution is to ease the
constraint on relying totally on the storage batteries.
• Above proposed solution necessitates the development of
advanced and smart power flow controllers and might be
expensive and may not be flexible to certain modes of
operation.

4. Hybridsystemtakenunderdiscussionandanalysis
Schematic Circuit Diagram

5. Detailed circuit contents

6. PVG: Akbaba Model & Characteristics
• Voltage across the PVG terminals
• Current delivered by the PVG when an external load is connected
across its terminals
• Power delivered by the PVG source
Voc: Open circuit voltage across the terminals of the PVG generator at an
insolation level
A, B, C: are parameters whose values depend on the insolation level. Such values
can be tabulated by performing laboratory tests.
Voltage Source Model

7. • Photovoltaic generator data
I-V Characteristics P-V Characteristics

8. FCG: Model & Characteristics
• Generated voltage from a fuel cell
Ethermo is the thermodynamically predicted voltage of the fuel cell
Ƞact represents the activation losses due to the kinetics reaction
Ƞohmic represents the ohmic losses
Ƞconc represents the concentration losses due mass transport
Voltage Source Model

9. • Fuel cell data
I-V Characteristics
The I-V characteristic of the fuel cell (FCG) used in this investigation is taken from
the MATLAB/Simulink/Sym Power systems toolbox, Version 7.9.0529 (R2009b)
and above

10. Power Bridge Rectifiers
• For any value of the firing angle greater than 90°, the average voltage VDC is
negative.
• This results in a negative value for the power at the DC side of the bridges.
That leads to the statement that such power is generated by the two
renewable energy resources (PVG and FCG) and it is injected into the AC side
of the bridges.

11. Firing Angle Controller
The absolute value of the error is checked whether it is between certain pre-set
limits or not. In the case of having an error beyond the pre-set limits, a product
of a non zero value with the sign of the tabulated error is integrated and
amplified.
Maxi. Power has been extracted from PVG source through use of such self
adjusted firing angle controller.
• Bridge carrying the PVG source

12. • Bridge carrying the FCG source.

13. PretendedDaily Insolationlevel
Other Parameters

14. Performance
• The performance of the proposed technique has been evaluated using
MATLAB/SIMULINK. That is done by pretending daily insolation levels.
• The performance consists of:
(1) measuring continuously the power consumed by the AC load
(2) power delivered by the PVG source
(3) the maximum power PVG,max of the PVG source at any pretended
insolation level
(4) the power delivered by the FCG source
(5) power delivered or absorbed by the AC voltage supply.

16. Conclusion
References:
(1) M. Taleb, S Haji and N. Mansour, “ Performance of A Hybrid
EnergySystem”–IEEEInternationalEnergyConference,2010
(2) M. Taleb, “Interconnection of PVG to a Main Supply: A
Practical Study,” Renewable Energy and Power Quality Journal
(REPQJ),March2010
(3) M. Akbaba, "Matching of AC loads to PVG for Maximum
Power Transfer Using an Enhanced Version of Akbaba Model
and Double Step-up Converter", International Journal of Solar
Energy,Vol.75,pp.17-25,2003.