ABSTRACT:
This paper presents the
comparison between the standalone photovoltaic (PV) system with battery-supercapacitor
hybrid energy storage system (BS-HESS) and the conventional standalone PV
system with battery-only storage system for a rural household. Standalone PV
system with passive BS-HESS and semi-active BS-HESS are presented in this study.
Two control strategies, Rule Based Controller (RBC) and Filtration Based
Controller (FBC), are developed for the standalone PV system with semi-active BS-HESS
with the aim to reduce the battery stress and to extend the battery lifespan.
The simulation results show that the system with semi-active BS-HESS prolongs
the battery lifespan by significantly reducing the battery peak current up to
8.607% and improving the average SOC of
the battery up to 0.34% as compared to the system with battery only system.
KEYWORDS:
1.
Renewable energy
2.
PV
3.
Hybrid energy storage
system
4.
Supercapacitor
5.
Battery
6.
Control strategy
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig. 1. Simulink Models. (a)
Standalone PV system with Battery-only Storage. (b) Standalone PV System with
Passive BS-HESS. (c) Standalone PV system with Semi-Active BS-HESS.
EXPERIMENTAL RESULTS:
Fig.
2. 24-hours Profiles. (a) Solar Irradiation Profile. (b) Load Demand (c) PV
Power Output.
Fig.
3. Battery Current. (a) Battery-only (b) Passive BS-HESS. (c) Semi-active
BS-HESS (RBC). (d) Semi-active BS-HESS (Moving Average).
Fig.
4. Supercapacitor Current. (a) Passive BS-HESS. (b) Semi-active BS-HESS (RBC).
(c) Semi-active BS-HESS (Moving Average).
CONCLUSION:
The BS-HESS shows the
positive impact to the battery and the overall system. The passive BS HESS is
easy to be implemented, but the improvement is not significant as it cannot be controlled.
Therefore, semi-active BS-HESS is a better configuration that improves the
battery lifespan and maximizes the level of utilization of the supercapacitor.
The system with semi-active BS-HESS (moving average filter) has significantly
smoothened the battery current. The system with semi-active BS-HESS (RBC) shows
a great capability in battery peak current reduction and the prevention of
battery deep discharge by reducing the peak power demand by 8.607% and improving
the average SOC of the battery by 0.34% as compared to the system with
battery-only system.
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