A general architecture for electric power management of small scale NCRE converters: Design methodology and validation

A design methodology, its validation and evaluation, for optimal electric energy power management NCRE (NonConventional Renewable Energy) converters used for battery charging is presented, targeting small-scale units (i.e. < 10 kW). It is a general-purpose solution that has been tested with different prime movers: river turbine, tidal turbine, wind turbine, and wave energy converter. There are two critical components in the configuration: the electric generator, and the buck converter or MPPT (Maximum Power Point Tracker). The design of these two components must give careful consideration to the behavior of the primary energy source as well as battery charging requirements. The topology selected for the generator is an axial flux generator with permanent magnets, because it allows matching the low optimal speed of the primary energy converters without the use of speed multipliers such as gears and pulleys. The programmable buck converter topology is selected because it can be used both as a voltage or current source, and hence it works well with battery charging,which is a primary application for small-scaleoff-gridNCRE converters. Cost-effectiveness of the solution is achieved by the simple design methods, low cost components and materials, and simple manufacturing methods.