A General Architecture for Electric Power Management of Small Scale NCRE Converters: Design Methodology and Validation

Abstract

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 smallscaleunits (i.e. b10 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 inthe configuration: the electric generator, and the buck converter or MPPT (MaximumPower Point Tracker).The design of these two components must give careful consideration to the behavior of the primary energysource as well as battery charging requirements. The topology selected for the generator is an axial fluxgenerator with permanent magnets, because it allows matching the low optimal speed of the primaryenergy converters without the use of speed multipliers such as gears and pulleys. The programmablebuck converter topology is selected because it can be used both as a voltage or current source, and henceit 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 andmaterials, and simple manufacturing methods.