Abstract:
This thesis presents a novel multi-port power converter topology for DC nanogrid
applications. The proposed topology integrates energy sources, loads and
energy storing elements using DC-link and magnetic coupling using a single converter.
As a result, it has fewer component counts and conversion stages than
the individual converters for each element in the nano-grid, which paves the way
for a more e cient system.
The rst part of this thesis presents a PV converter topology designed and
developed in the laboratory. This circuit topology integrates two PV modules
and boosts the input voltage into a 120V DC voltage level. However, switching
loss of the converter is signi cant due to the hard-switching operation. Therefore,
switching control strategy of the converter has been modi ed to minimize
switching losses with the assistance of the existing parasitic elements. The operation
of the power converter with the proposed switching control strategy is
mathematically analyzed and veri ed using simulation results. The design is further
validated using the experimental results obtained using a 250 W hardware
prototype.
Moreover, a bi-directional high step-up/down converter is designed and developed
to integrate an energy storing element into the system. The bi-directional
converter step downs 120 V DC link voltage to an extremely low voltage (10-16
V DC) to charge a Li-ion battery pack. When the solar power is not available,
the proposed converter discharges the Li-ion battery to regulate the 120 V DC
link. The operation of the battery interfacing converter is validated and veri ed
using both simulation and experimental results.
The conclusions and suggestions for the further development have been presented
at the end of this thesis.
Citation:
Gunawardena, L.H.P.N. (2019). Design and implementation of a multi-port power converter topology for DC nano-grid [Master’s theses, University of Moratuwa]. Institutional Repository University of Moratuwa. http://dl.lib.mrt.ac.lk/handle/123/16058