DC Link Voltage Stabilisation in Hybrid Renewable Diesel Systems

Constant Speed diesel generators have been used in remote and isolated areas to provide electricity for over half a century and in this time they have remained largely unchanged. Although they have been mated with other forms of generation, especially wind and photovoltaic successfully but generally to the detriment of the diesel generator. To alleviate this problem in this paper a modelled a variable speed diesel generator (VSDG) has been modelled as part of a hybrid renewable system. The benefits of a VSDG are explained and results show the fuel savings possible over a standard diesel generator. An experimental test rig has been built and the DC link stability has been assessed with and without different forms of short term energy storage. It is shown that supercapacitors can be utilised for maintaining the DC link voltage effectively.