Supplemental field excitation for permanent magnet rotor of pilot exciter

• US 4,015,189 A
• Filed: 03/15/1976
• Issued: 03/29/1977
• Est. Priority Date: 03/15/1976
• Status: Expired due to Term

• Current Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Original Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Inventors: Gorden, Dale I.
• Primary Examiner(s): Hickey, Robert J.
• Application Number:
  US05/666,810
• Time in Patent Office: 379 Days
• Field of Search: 322/25, 322/28, 322/46, 322/59, 310/181
• US Class Current: 322/46
• CPC Class Codes: H02P 9/36 using armature-reaction-excited machines

Abstract

In a synchronous dynamoelectric machine having a pilot exciter which energizes a brushless exciter, voltage regulation and forcing excitation are provided by a plurality of field coils which are disposed upon selected ones of a plurality of permanent magnets carried by the rotor of the pilot exciter. The field coils are connected together to constitute a field winding and are electrically connected to receive direct current excitation from the output of a rotating rectifier assembly through coupling means, such as a direct current regulator. In operation, the regulator is responsive to changes in the current flowing through the field winding of the synchronous dynamoelectric machine and provides a direct current output signal to the permanent magnet field winding to increase the magnetic field strength of the associated permanent magnets.

Claims

1. In a synchronous dynamoelectric machine having a rotor member disposed upon a shaft, said shaft being disposed for rotation by a prime mover, a field winding disposed on said rotor member, a main exciter having a stator member carrying a field winding and a rotor member disposed on said shaft carrying an armature winding, a rotatable rectifier assembly operable to convert alternating current to direct current having an input circuit connected to receive alternating current excitation from said main exciter armature and an output circuit connected to conduct direct current excitation through said synchronous dynamoelectric machine field winding, a pilot exciter operable to derive electrical power from the rotational energy of said shaft, said pilot exciter having a permanent magnet rotor member comprising a plurality of permanent magnets arranged in alternating magnetic polarity to establish a rotating magnetic field when said shaft is rotated, and said pilot exciter having a stator member carrying an armature winding which is coupled by magnetic induction with the magnetic field provided by said permanent magnet rotor member,

the combination with said pilot exciter of a plurality of field coils disposed upon selected ones of said permanent magnets, said field coils being connected together in series electrical relation to constitute a field winding, and means for deriving direct current excitation from the output circuit of said rotating rectifier assembly connected to supply a predetermined function of said direct current excitation to said permanent magnet field winding.

2. The combination as defined in claim 1 wherein said direct current excitation deriving means comprises a direct current regulator having an input circuit connected to receive direct current excitation from the output circuit of said rotating rectifier assembly and having an output circuit connected to conduct direct current through said permanent magnet field winding.