Testing the electrical power generation of a prototype multi-bladed wind turbine system

Abstract

The Faculty of Engineering has been involved in the design of a small-scale nine-bladed wind turbine to provide an efficient alternative to the Chicago windmills distributed across the rural areas of the Maltese Islands. A prototype was constructed and deployed at the Government experimental farm in Għammieri in previous projects. The wind turbine is planned to generate electricity and supply it to the local power network through a wind grid-tie inverter. This dissertation focuses on the series of tests taking place to study the electrical performance of the prototype under controlled laboratory conditions, in the field, and through software modelling. The emulator rig situated in the Power Conversions lab was used to carry out tests under controlled conditions. The DC drive settings and the previously derived inverter characteristic were improved to extend the rotational speed range of the generator. The effect of the increasing temperature of the generator on the electrical parameters was identified. Several field tests were performed under various wind conditions. A total of approximately 7 hours of data was gathered during these tests, 5 of which were useful to the data analysis. The temperature effect was also evident in the field tests despite the cooling effect of the wind. The inverter efficiency curve was extracted from the field tests and was used to translate the Pg-VDC characteristic programmed into the inverter to an equivalent PDC-VDC characteristic for simulation purposes. A software model was used to recognise the impact of each parameter on the overall performance of the small-scale WECS. The translated PDC-VDC characteristic was used to drive the simulation. The wind direction was not considered for this model since the yaw signal was not available. The results from the three sources used showed close agreement between the obtained characteristics with salient points corresponding to the programmed inverter characteristic.