Optimisation of a small non controlled wind energy conversion system for stand-alone applications

Abstract

This  article  proposes  a  method  to  optimize  the  design of a small fixed-voltage wind energy conversion system (WECS).  The  system  is  composed  of  commercially  available  elements which are: a small horizontal axe wind turbine, a one-stage  gearbox,  a  permanent  magnet  synchronous  generator,  a  diode  bridge  and  a  battery  bank.  As  there  are  no  controlled  devices on the system, the design must be carefully done to find the  configuration  that  maximizes  both,  the  system  utilization  and  the  system’s  output  power.  Using  the  mechanical  and  the  electrical    power    equations,    an    optimization    problem    is    proposed.   This   problem   is   aimed   to   find   the   optimal   combination  of  the  gearbox  ratio  and  the  battery  voltage  in  order  to  extract  the  maximum  amount  of  energy  form  the  WECS.   The   mechanical   power   is   modelled   using   a   new   proposed   power   coefficient   function   approximation.   The   constrained    optimization    problem    is    then    solved    by    a    MATHEMATICA©  genetic  algorithm  based  routine.  Results  are  shown and discussed.