Constant lock circuit for DC micro-grid system
The escalating rates of fossil fuels have enforced researchers to seek renewable energy systems. Power generation from fossil fuels may not be possible for very long as they are depleting. Recently, the researchers have been interested in the techniques of exploiting renewable energy sources such...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2017
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| Online Access: | http://psasir.upm.edu.my/id/eprint/71211/1/FK%202017%2075%20-%20IR.pdf http://psasir.upm.edu.my/id/eprint/71211/ |
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| Institution: | Universiti Putra Malaysia |
| Language: | English |
| Summary: | The escalating rates of fossil fuels have enforced researchers to seek renewable energy
systems. Power generation from fossil fuels may not be possible for very long as they
are depleting. Recently, the researchers have been interested in the techniques of
exploiting renewable energy sources such as solar, hydro, wind, etc. The energy
conversion from water flow streams to electrical energy via Pico turbine generator is
the only solution. The only disadvantage of hydro energy is the seasonal variations
when it cannot generate enough power to meet the load demand. Also, the changing of
water flow rates causes a variable output voltage. In this renewable system, continuous
power flow to meet load demand is not possible. For integration of REs to optimal
results, an excellent option for energy production can be obtained by using a microgrid
system by combining the renewable energy source with a backup source such as
a utility grid.
Therefore, this thesis develops DC micro-grid control strategies based on providing
continuous load power regardless of the generated power and load demand. The
comparison between generated power and load consumption leads the monitoring
system to determine the proper mode that the system should follow. Three modes come
into view during DC micro-grid operations. These operational scenarios are the standalone
scenario, grid scenario, and feedback scenario.
A simulation of the DC micro-grid in order to provide a continuous load demand based
on using a CLC which is keeping the DC link at a 24v constant value is designed. Due
to the ongoing interaction between the fluctuating weather conditions and load
demands in a DC micro-grid, each source needs to be in a highly precise control
regulation to link with the DC link node. So,it requires voltage compatibility of all
sources associated with the DC link bus for keeping the stability of the DC link at a
constant value, Moreover, parallel sources connection for sharing power at a DC micro-grid have problems such as reverse current, and degradation of power
conversion efficiency, due to a slight difference between output voltages. For all the
above, there is a need for a new interface block control to deal with these problems.
For this, an algorithm system strategy for utilizing a Constant Lock Circuit in the DC
micro-grid aims at maintaining a constant DC link voltage at the desired constant value
of 24v to ensure high stability voltage and current without any ripple. Furthermore, it
is deemed relevant to give priority to the renewable energy production for supplying
load extracting maximum power from the REs. Moreover, it is also necessary to
provide an adequate load demand regardless the power generation amount for
satisfying an easy connection between two parallel sources for sharing power. On top
of that, the power that the load needs from the backup source to meet load demand
should be compensated to export the surplus RE power to the backup source.
The models of the DC micro-grid with CLC system are simulated in Proteus8
Professional. Results obtained from simulations have proven that the proposed
algorithm system strategy have achieved its aims through keeping constant 24v with
percentage error 0.059%. |
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