The brushless doubly fed reluctance machine and the synchronous reluctance machine-a comparison

Abstract

The brushless doubly fed reluctance machine (BDFRM) is related to the better known brushless doubly fed induction machine (BDFIM). Research into doubly fed machines is motivated by the fact that they allow the use of a partially rated inverter in many variable-speed applications. Research into the BDFRM has been largely ignored in comparison to the BDFIM, despite the fact that it has the potential for greater efficiency as compared to the BDFIM, and the rotor is simpler to manufacture. This paper compares the BDFRM and its singly fed cousin, the synchronous reluctance machine. This is a natural comparison since both machines use the same reluctance rotor. The first part of the paper establishes relationships between the inductances of the two machines. This is then used to facilitate a comparison using the constraints that both machines have the same amount of active material, i.e., the same amount of copper and iron, and that the copper losses for both machines are the same. This analysis also allows an approximate comparison with the conventional squirrel-cage induction machine. The analysis is carried out using machine-independent normalizations.

Design and control of a high-efficiency Doubly-Fed Brushless machine for wind power generator application

“…Many papers have been published continuing the discussions in the DFBM principles, operational characteristics, and possible advanced control methods and applications. The most important development in this stage is that researchers have formally established the identity of DFBM as a special machine, instead of treat it as two machines in "self-cascade", that is, a combination of two induction machines built on a common shaft or single stator house [9][10][11][12]. Through their research work, it was established that, regardless rotor types, the DFRM terminal characteristics resemble those of a wound rotor induction machine.…”

Steady-state performance of a line-start synchronous reluctance motor with capacitive assistance

“…The most popular of these configurations is the dual-winding induction machine in which both windings have different pole numbers and the rotor have either the conventional squirrel-cage rotor or a rotor whose pole number is a weighted average of the number of poles of the stator two windings [3]. The brushless doubly-fed reluctance machine, BDRFM [4] have also attracted renewed attention because of its slip-energy recovery nature which allows the machine to work with inverters of half the rating of the machine if the main winding is fed directly from the mains and the second winding fed from the inverter. BDFRM can operate successfully in both synchronous and asynchronous modes, but has a very low dynamic performance.…”

Modeling and analysis of BCDFM: effect of rotor‐phase sequence connection

“…As a drawback the SDFM relies on the brush-ring system enabling the connection to the rotor windings (Smith, 1967). Brushless type of doubly fed machines are the denoted brushless doubly fed machine (BDFM) (Wallace et al, 1993;Williamson et al, 1997;Zhou et al, 1997) and the doubly fed reluctance machine (Xu et al, 1991;Betz and Jovanovic, 2000).…”