INTEGRATED INVERTER FOR BUILDING INTEGRATED PHOTOVOLTAICS

abstract

With the cost of the conventional sources of energy such as oil and gas steadily increasing, and the cost of silicon and solar cells decreasing, the conversion of solar energy to electricity is rapidly becoming an economically viable alternative, with the nature having abundance of solar power. However, the output of a solar cell is in the form of direct current (dc) power, while most appliances and other electrical devices in residential used require an alternate (ac) power normally supplied by the utility. The required conversion to match the different kinds of source and load power can be realized by dc-to-ac inverters of two different types: Stand-alone inverter and grid-connected inverter. The solar array power fluctuates considerably during each day, depending on the insolation level, weather conditions (clouds) etc. the residential load current also experiences extremely wide variations in the course of a day depending on the actual usage of various appliances in the residence. Hence a need to balance the source and load power flow is created.

Development of new technologies for low-cost manufacturing of thin-film photovoltaic (PV) power cells will enable new types of building materials that integrate photovoltaic power generating elements. In this role, the photovoltaic modules become architectural elements, requiring properties such as a low profile, ease of connection to the utility system, and the ability to maximize energy capture in a complex physical environment having shadows and reflections. In addition, the ability to generate ac simplifies connection to the ac utility system and can substantially reduce installation and other balance-of-system costs. Meeting these requirements requires low-power inverters having very low profile and high efficiency; which has led to the development of Micro-inverters.