TECHNOLOGY OF THIN LAYER SILICON SOLAR CELLS AND APPLICATIONS TO POWER SYSTEMS
This research work consists of two major areas and the results obtained are summarized as follows: Part I. The aim was to develop thin film a-Si:H solar cells, but due to uncontrolled reasons the work was restricted to a-Si solar cells. Vacuum deposited layers, of thickness 0.2-1.4 mum on different substrates held at various temperatures, studied by TEM were found to be amorphous. At 550-580 degrees C these a-Si layers were converted into poly-Si. The room temperature I-V characteristics of Al and Au Schottky diodes on n-type, p-type and near intrinsic a-Si layers, evaporated on stainless steel and Al covered glass substrates held at room temperature, are significantly different, their differences being similar to those of Al and Au diodes on single crystalline silicon. When the same diodes were formed on poly-Si, produced by heating a-Si at 550- 600 degrees C, the I-V characteristics were very much improved. In all cases, however, the electrical characteristics were rather poor, leading to a very weak photovoltaic effect. Part II. The second major area of the project refers to the design, construction and testing of appropriate power conditioning and interface equipment for the parallel operation of PV power systems and the utility grid. Here, our effort focused upon the design and construction of a line-commutated dc to ac inverter for the parallel operation of a PV system with the utility grid. The inverter incorporates appropriate interface, filtering and protection devices necessary to assure the reliable and safe operation of the interconnected system. A maximum power point tracking subsystem has been included in the design so that system performance is continuously enhanced by transferring maximum power from the PV source to the load. The study methodology consisted of analytical and experimental approaches. A computer model simulates overall system performance while experimental studies are performed using appropriate PV simulators. The impact of distributed photovoltaic systems upon utility load supply management practices is addressed using probabilistic modeling techniques. Results show how PV characteristics affect utility production costs and system reliability. Finally, a methodology is presented for assessing the impact of PV systems and wind generator clusters penetrating into the autonomous grid of Kythnos island. Lack of data has prevented validation of the proposed approach.
Bibliographic Reference: REP EUR 9841 EN (1985) MF, 95 P., BFR 150, BLOW-UP COPY BFR 475, AVAILABILITY: EUROFFICE, LUXEMBOURG POB 1003.
Availability: Can be ordered online
Record Number: 1989123118000 / Last updated on: 1987-01-01
Available languages: en