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Title: Interior Permanent Magnet Reluctance Machine with Brushless Field Excitation

In a conventional permanent magnet (PM) machine, the air-gap flux produced by the PM is fixed. It is difficult to enhance the air-gap flux density due to limitations of the PM in a series-magnetic circuit. However, the air-gap flux density can be weakened by using power electronic field weakening to the limit of demagnetization of the PMs. This paper presents the test results of controlling the PM air-gap flux density through the use of a stationary brushless excitation coil in a reluctance interior permanent magnet with brushless field excitation (RIPM-BFE) motor. Through the use of this technology the air-gap flux density can be either enhanced or weakened. There is no concern with demagnetizing the PMs during field weakening. The leakage flux of the excitation coil through the PMs is blocked. The prototype motor built on this principle confirms the concept of flux enhancement and weakening through the use of excitation coils.
Authors:
Publication Date:
OSTI Identifier:
886009
Report Number(s):
ORNL/TM-2005/222
TRN: US200617%%313
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Technical Report
Research Org:
ORNL
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; DEMAGNETIZATION; EXCITATION; FLUX DENSITY; MOTORS; PERMANENT MAGNETS