This paper proposes a high-efficiency two stage
three-level grid-connected photovoltaic inverter. This
work deals with the frequency regulation, voltage regulation, power management
and load levelling of solar photovoltaic (PV)-battery-hydro based microgrid
(MG). In this MG, the battery capacity is reduced as compared to a system, where
the battery is directly connected to the DC bus of the voltage source converter
(VSC). A bidirectional DC–DC converter connects the battery to the DC bus and
it controls the charging and discharging current of the battery. It also
regulates the DC bus voltage of VSC, frequency and voltage of MG. The proposed
system manages the power flow of different sources like hydro and solar PV
array. However, the load levelling is managed through the battery. The battery
with VSC absorbs the sudden load changes, resulting in rapid regulation of DC
link voltage, frequency and voltage of MG. Therefore, the system voltage and frequency
regulation allows the active power balance along with the auxiliary services
such as reactive power support, source current harmonics mitigation and voltage
harmonics reduction at the point of common interconnection. The experimental
results under various steady state and dynamic conditions, exhibit the excellent
performance of the proposed system and validate the design and control of
proposed MG.
SOFTWARE: MATLAB/SIMULINK
Fig. 1 Microgrid
Topology and MPPT Control
(a) Proposed PV-battery-hydro MG,
EXPECTED SIMULATION RESULTS:
Fig. 2 Dynamic performance of PV-battery-hydro
based MG following by solar irradiance change
(a) vsab, isc, iLc and ivscc, (b) Vdc, Ipv, Vb and Ib, (c) vsab, isa, iLa and ivsca, (d) Vdc, Ipv, Vb and Ib
.
Fig.3 Dynamic performance of hydro-battery-PV
based MG under load perturbation
(a) vsab, isc, Ipv and ivscc, (b) Vdc, Ipv, Vb and Ib, (c) vsab, isc, Ipv and ivscc, (d) Vdc, Ipv, and Vb
CONCLUSION:
In the proposed MG, an integration
of hydro with the battery, compensates the intermittent nature of PV array. The
proposed system uses the hydro, solar PV and battery energy to feed the voltage
(Vdc), solar array current (Ipv), battery voltage (Vb) and
battery current (Ib). When the load is increased, the load demand exceeds
the hydro generated power, since SEIG operates in constant power mode
condition. This system has the capability to adjust the dynamical power sharing
among the different RES depending on the availability of renewable energy and
load demand. A bidirectional converter controller has been successful to maintain
DC-link voltage and the battery charging and discharging currents. Experimental
results have validated the design and control of the proposed system and the
feasibility of it for rural area electrification.
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