| Available from UMI in association with The British Library.; The overall objective of the project is to reduce the cost per unit volume of lifting water using a PV water pumping system. Proper system design and good matching between the different components of a photovoltaic system, should be capable of improving overall system efficiency. This results in a requirement for fewer PV modules, thus lowering the cost of this aspect of the system. However, the component characteristics required for optimum matching may preclude the use of widely available, standard units, leading to extra cost which may offset the benefits obtained by reduction in the number of PV modules needed.; The prime objective of this thesis was to develop a power electronic interface (PEI) unit to operate between a photovoltaic (PV) array and the remainder of the system with particular reference to water pumping applications. This PEI unit would allow the use of standard, low cost inverters and motor-pump sets, without compromising the system efficiency. The PEI unit is a step-up DC-DC converter. This converter transforms the varying voltage from the PV array to a constant DC level compatible with the inverter's requirements.; In order to determine the optimum design of the PEI unit, a small scale version was built and tested. This consisted of a simulated PV module, of a maximum power output of 20 watts (nominally 20 V, 1 A), the DC-DC converter giving a step up to an output of 60V and a simulated load.; The use of a DC-DC step-up converter, and the suggested peak power point tracker, using the technique shown in the study, represents a new concept in the design of small scale (up to 5kW) PV system, and the circuitry developed exhibits excellent stability. Therefore, the success of the small scale version of the PEI unit is expected to lead to the design of a full scale 1 kW version, which can be achieved by scaling up the present control circuit. |
