Case Study: Vibration analysis of a prototype of a small-scale high-speed generator for a hybrid electric vehicle

Abstract

A series of high-speed generators (HSGs) for a hybrid electric vehicle is being researched at Imperial College. One of the key features of these products is their compactness (about 10 per cent of the weight of a comparable diesel generator set), making them highly portable. A brief description of an HSG is given here. In order to operate these generators safely, it is very important to be able to predict and analyse their dynamic behaviour. For this purpose, a systematic procedure is proposed to develop a finite element (FE) model to predict natural frequencies under operating conditions. In the procedure, the relationships between FE analyses, modal analyses and results of a running test are established. A prototype of a 100 kW HSG was made by adopting a new concept which used a hollow shaft to achieve very efficient cooling. Vibration analyses of the prototype using the proposed procedure were carried out. Finally, the results of computations and experiments for the prototype are presented and compared.