A comparative study of control strategies for performance optimisation of brushless doubly-fed reluctance machines

Abstract EN

The brushless doubly-fed machine (BDFM) allows the use of a partially rated inverter and represents an attractive cost-effective candidate for variable speed applications with limited speed ranges.

In its induction machine form (BDFIM), the BDFM has significant rotor losses and poor efficiency due to the cage rotor design which makes the machine dynamic models heavily parameter dependent and the resulting controller configuration complicated and difficult to implement.

A reluctance version of the BDFM, the brushless doubly-fed reluctance machine (BDFRM), ideally has no rotor losses, and therefore offers the prospect for higher efficiency and simpler control compared to the BDFIM.

A detailed study of this interesting and emerging machine is very important to gain a thorough understanding of its unusual operation, control aspects and compromises between optimal performance and the size of the inverter and the machine.

This paper will attempt to address these issues specifically concentrating on developing conditions for various control properties of the machine such as maximum power factor, maximum torque per inverter ampere and minimum copper losses, as well as analyzing the associated trade-offs.