High-efficiency interior permanent-magnet synchronous generators with minimal voltage regulation for nano and pico hydro generation

This paper presents a successful design of a high-efficiency interior permanent-magnet generator which keeps terminal voltage constant from no load to rated load under a constant speed. This means the generator does not need the voltage control due to the voltage drop associated with the increase in load. Time-stepping finite-element analysis has been used to successfully predict the electromotive force of the prototype generators. A 1-kW 4-pole prototype generator has been designed, built, and tested for nano and pico hydro generation. It has been found from experimental results that the voltage regulation has been extremely low and its value was 0.3%.