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Summary of the ThesisA hybrid power system which consists of diesel Genset, PV-arrays and wind turbines with energy

storing devices (battery bank) and power electronic devices has been discussed in this paper to

achieve an efficient and cost competitive system configuration so that hybrid power sources could

improve the life of people especially in rural areas where electricity from the main grid has not

reached yet. For the different energy sources, where some are AC sources and others DC sources,

different connecting topologies are proposed in this paper. The proposed connecting configurations

are compared to select the one with the best efficiency of power consumption to the consumers by

considering each power sources independently. It is found that best efficiency of power consumption

can be achieved with the Mixed-coupling HPSs, when compared with the other topologies and the

selected topology is used for further investigation. With typical AC-load profiles, solar irradiation

and wind speed profiles of a typical site, the sizing approaches of each energy sources, the battery

bank and power electronic devices are discussed in this paper. Having described the preliminary

sizing approaches of system elements for the selected topology, different power management

techniques are defined based on the typical load demand curves, where the diesel Genset gets

supports from the renewable energy sources and the battery bank. For each PMS, mathematical

models are devised based on the power balance between the supply and the demand sides,

charging/discharging control of the battery and switching controls for the Genset. The differentsystems which resulted from the defined power management strategies are modeled using

MATLAB/Simulink blocks. The appropriate sizes of system elements are applied to each PMS and

the models are simulated. The simulation results (power shares among the power sources to supply

the demand, the losses and energy levels of the battery banks) verify that the results are in

accordance to the mathematical modeling which depends on the governing energy and power

equations. The instantaneous demand is met at every instant of time and the charging/discharging of

the battery is controlled between the upper and lower limits. The proper sizing of system elements

result in the efficient utilization of the power from the renewable sources and the battery bank. It has

been also observed that the sizes of the different energy sources, DODs and thus the lifetime of the

battery banks are affected with the different PMSs. This in turn brings about numbers of

replacements of the batteries, for those with high DOD, before the end of the lifetime of the hybrid

system.Finally, the hybrid system with the selected topology is investigated for the optimization criterion.

This is studied from two points of views: fuel consumption of the Gensets with each PMS, and thus

their consequences in depleting the environment. Furthermore, the cost analysis of system elements

and the whole system corresponding to each PMS are investigated. The different PMSs result in

different fuel consumptions by the Gensets. This in turn results in different impacts on the

environment. The OG PMS followed by RBAG and then GBA PMSs show the highest cyclic fuel

consumptions in the same order for load profile-A. Similarly, OG PMS followed by RBA and then

MOO PMSs show the iv

highest cyclic fuel consumptions for load profile-B. For this reason, it can be concluded that these

PMSs also have the largest impact in polluting the environment. The study of the cost analysis is

performed in three steps. Firstly, the capital investment costs are performed for each PMS. The

Only RESs PMSs (OWB, OPB and PWB PMSs) require huge capital investments and the OG PMSs

require the least initial capital cost. Secondly, the lifetime variable costs are investigated over the

lifetime of the system. The renewable sources (PV-arrays and wind turbines) and the power

converters require no replacements and little operation and maintenance costs. The battery banks

require replacement costs, depending on the PMSs where the DOD of the battery bank is affected,

in addition to some operation and maintenance costs. However, the Genset requires continuous

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fuel supply resulting in huge fuel cost over the system life. Over and above, the operation and

maintenance costs of the Genset subsystem are relatively higher than other power sources.

Replacements are also considered after 10 years of service time for the Gensets. These all result in

very large variable costs of the Genset over the renewable energy sources. By combining the capital

costs with the variable lifetime costs, the life-cycle costs of the systems for the different PMSs are

analyzed and it is found that the renewable energy sources and/or the hybrid sources are cost

competitive over the system lifetime despite the huge capital investment of the renewable sources.