This
study proposes a varying phase angle control (VPAC) in isolated bidirectional
dc–dc converter (IBDC) for integrating battery storage unit to a DC link in a
standalone solar photovoltaic (PV) system. The IBDC is capable of power transfer
using high step up/down ratio between DC link and battery. The VPAC control
proposed in this study effectively manage the power flow control between the
battery storage unit and the solar PV fed DC link by continuously varying the
phase angle between high voltage and low voltage (LV) bridge voltage of the
IBDC. The solar PV system is incorporated with the maximum power point tracking
using DC–DC converter. In order to control the voltage across the AC load a
voltage source inverter is used. The study also presents the design aspects of
the IBDC converter for the application considered. The performance of the proposed
power flow control strategy has been studied through PSCAD/EMTDC simulation and
validated using LPC 2148 ARM processor.
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig. 1 Block
diagram for proposed standalone system
(a) Generalised block diagram, (b) Mode 1
operation, (c) Mode 2 operation, (d) Mode 3 operation
.
Fig. 2 Simulation
results of IBDC
(a) Battery
current during change in mode 1 to mode 2, (b) Battery current during change in mode 2 to mode 1, (c) Solar PV power, load power and
battery power during change in
mode 1 to mode 2, (d) Solar PV power, load power and battery power during change
in mode 2 to mode 1
CONCLUSION:
The proposed variable phase angle
control of IBDC converter balances the power flow between the solar PV system,
battery storage unit and AC load in all the modes. The VPAC algorithm ensures
that the, (i) solar PV system delivers maximum demanded power corresponding to
the load and battery gets charged/ discharged through the available
excess/short power. The governing mathematical formulation of problem reveals
the dependency of average battery current on phase angle between the voltages
of LV and HV side of the IBDC converter and hence provides a strategy to
control the power flow. The analysis presented can be used to design the
passive components and switches of the IBDC. From the obtained results, the
performance of the proposed VPAC has been established with smooth transition of
power flow between the PV fed DC link and the battery through the IBDC
converter. The maximum power is extracted from the solar PV and AC load voltage
is controlled in all the modes.
REFERENCES:
[1] Bull,
S.R.: ‘Renewable energy today and tomorrow’, Proc. IEEE, 2001, 89,
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[2]
Solodovnik, E.V., Liu, S., Dougal, R.A.: ‘Power controller design for maximum
power tracking in solar installations’, IEEE Trans. Power Electron., 2004, 19,
(5), pp. 1295–1304
[3] Kuo,
Y.-C., Liang, T.-J., Chen, J.-F.: ‘Novel maximum-power-point tracking controller
for photovoltaic energy conversion system’, IEEE Trans. Ind. Electron., 2001, 48,
(3), pp. 594–601
[4]
Koutroulis, E., Kalaitzakis, K., Voulgaris, N.C.: ‘Development of a microcontroller-based,
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