Abstract
In order to reduce emissions of greenhouse effect gas, the development of all renewable energy is required. Therefore, this paper focused on small-sized hydraulic generator. Because the small scale hydropower has a large amount of potential power generation. Standard mechanical bearings are installed in conventional small-sized hydraulic generator to support the rotating shaft. However, mechanical ball bearings cause rotational loss, noise and limitation of device durability. In order to upgrade performance of hydraulic generator, permanent magnet hybrid type magnetic bearing is proposed in this study. Stator is designed by finite element method magnetic field analysis. According to the analytical result, by making the root of stator salient pole wider and eliminating magnetic saturation, stronger bearing power was obtained. And a simple experimental setup was fabricated based on the analytical result. The bearing force characteristic and the negative spring force characteristic were clarified by static characteristics evaluation. Moreover, in order to confirm dynamic performance in time domain, impulse response was measured and result showed good response performance. In addition, by using measured coefficient of bearing force and negative spring force, numerical simulation was carried out to check dynamic performance in frequency domain. Simulation result of frequency response showed wide enough bandwidth.
