Solar Concentrated Photovoltaic Systems Using Spectral Splitting.

摘要

The sun is an abundant source of natural, renewable energy that can be used to help meet the energy needs throughout the world. Photovoltaic (PV) solar cells are used to convert sunlight directly into electricity. Optics are used in concentrated photovoltaic (CPV) systems in order to collect large amounts of sunlight and concentrate it onto smaller PV devices, thus decreasing the amount of expensive solar cells used in the system. In spectral splitting CPV systems the incident solar energy is split into multiple optical paths and multiple types of solar cells are used in order to more efficiently convert the sunlight into electricity.;This thesis discusses spectral splitting CPV systems that use dichroic thin film filters to split the spectrum. Two compact systems are discussed that are meant to be used for portable power applications to charge personal electronic devices. Proof-of-concept prototypes were made of each system. The system efficiency and acceptance angle is measured for each device. Differences between the measurements and the system are investigated. An efficiency of 38.2% ±1.9% is measured for one of the systems. A system of the same design, made by a collaborator, has a measured efficiency of 38.5% ±1.9%, which is the current world record for a sub-module.;A third, larger system is also discussed. The dichroic filter is deposited on a parabolic surface, resulting in a variation in the thickness of the coating across the part that improves the overall performance of the dichroic relative to a uniform thickness coating. The variable performance of the dichroic is measured and applied to the system model. The modeled thickness variation is optimized to find the peak system efficiency. The optimization leads to a narrower dichroic cut-off region and an increase in the system efficiency of the main system analyzed of 0.5% (absolute efficiency) compared to the efficiency of the system with a uniform thickness dichroic coating.