Dynamoelectric machines brushless supplemental excitation system

• US 4,336,486 A
• Filed: 01/09/1980
• Issued: 06/22/1982
• Est. Priority Date: 01/09/1980
• Status: Expired due to Term

• Current Assignee: Siemens Westinghouse Power Corporation
• Original Assignee: Westinghouse Electric Corporation (Paramount Global (f/k/a ViacomCBS Inc.))
• Inventors: Gorden, Dale I., Petersen, Sigrud R.
• Primary Examiner(s): HICKEY, ROBERT
• Application Number:
  US06/110,570
• Time in Patent Office: 895 Days
• Field of Search: 322/17, 322/59, 322/60, 322/63, 322/72, 322/86, 322/87, 322/88, 322/44, 322/45
• US Class Current: 322/63
• CPC Class Codes: H02P 9/12 for demagnetising; for reducing effects of remanence; for preventing pole reversal
• CPC Class Codes: H02P 9/36 using armature-reaction-excited machines

Abstract

For a dynamoelectric machine, excitation power is supplied by a main exciter having two field windings. A first field winding is driven by a pilot exciter which supplies base excitation (small signal) for the main exciter. Forcing excitation (large signal) is supplied by the second field winding which is driven by an external, supplemental power source. The main exciter can thus provide the appropriate excitation for both normal and transient operating conditions. In addition, by switching the controlled rectifier elements associated with the supplemental power source, the second field winding is also capable of providing fast de-excitation for the main exciter.

Claims

1. In combination,

a synchronous dynamoelectric machine having a stator member carrying an alternating current armature winding and a rotor member carrying a direct current field winding;

a main exciter for said synchronous dynamoelectric machine having a rotor member carrying an armature winding, and a stator member having both a first and a second field winding, said first and said second field windings connected in parallel electrical relation to one another;

a rotatable rectifier assembly having an input circuit connected to receive alternating current power from said main exciter armature, and an output circuit connected to conduct direct current excitation through said synchronous machine rotor field winding;

a pilot exciter having a stator member carrying an armature winding and a permanent magnet rotor member, said pilot exciter being connected electrically in series with said first field winding;

means mechanically connecting said dynamoelectric machine rotor member, said rotatable rectifier assembly, said main exciter rotor member, and said pilot exciter permanent magnet rotor member for rotation;

means for converting alternating current to direct current having an input circuit connected to receive electrical power from said pilot exciter armature winding and having an output circuit connected to supply direct current to said first field winding of said main exciter;

means for deriving direct current excitation from a supplemental power source, said deriving means having an input circuit connected to receive electrical power from said supplemental power source and having an output circuit connected to supplement the direct current excitation applied to said second field winding of said main exciter, said supplemental power source being connected electrically in series with said second field winding and electrically independent of said dynamoelectric machine; and

whereby said pilot exciter and said supplemental power source are connected electrically in parallel to and regulated independently of each other.

2. The combination of claim 1 further comprising a means for preventing current reversal, said means electrically connected between said output circuit of said converting means and said first field winding of said main exciter.

3. The combination as defined in claim 1 wherein said converting means and said deriving means each comprise a plurality of controlled rectifier elements electrically connected in a bridge arrangement, said controlled rectifier elements being connected in a positive pole relation with respect to the output circuit of said bridge to conduct positive current, when gated on, from its associated power source to said main exciter field winding.

4. The combination as defined in claim 3 including means for deriving a first control signal proportional to the main exciter field excitation and to the power output of said synchronous dynamoelectric machine, said first control signal being operably connected to said converting means to control the gating of said controlled rectifier elements of said converting means in response to said first control signal;

and means for deriving a second control signal which corresponds to a predetermined function of the power output of said generator and of the main exciter field excitation, the output of said second control means being operably connected to said deriving means to control the gating of said controlled rectifier elements and of said deriving in response to said second control signal.

5. The combination as defined in claim 2 wherein the means for preventing current reversal is a connecting diode.

6. The combination as defined in claim 1 wherein the first field winding and the second field winding are wrapped about a common core.

7. In combination,

a synchronous dynamoelectric machine having a stator member carrying an alternating current armature winding and a rotor member carrying a direct current field winding;

a main exciter for said synchronous dynamoelectric machine having a rotor member carrying an armature winding, and a stator member having both a first and a second field winding said first and said second field windings connected in parallel electrical relation to one another;

a rotatable rectifier assembly having an input circuit connected to receive alternating current power from said main exciter armature, and an output circuit connected to conduct direct current excitation through said synchronous machine rotor field winding;

a pilot exciter having a stator member carrying an armature winding and a permanent magnet rotor member;

means for mechanically connecting said dynamoelectric machine rotor member, said rotatable rectifier assembly, said main exciter rotor member, and said pilot exciter permanent magnet rotor member for rotation;

means for converting alternating current to direct current having an input circuit connected to receive electrical power from said pilot exciter armature winding and having an output circuit connected to supply direct current to said first field winding of said main exciter;

means for deriving direct current excitation from a supplemental power source, said deriving means having an input circuit connected to receive electrical power from said supplemental power source and having an output circuit connected to supplement the direct current excitation applied to said second field winding of said main exciter;

means for deriving a first control signal proportional to the main exciter field excitation and to the power output of said synchronous dynamoelectric machine, said first control signal being operably connected to said converting means to control the gating of said controlled rectifier elements of said converting means in response to said first control signal;

means for deriving a second control signal which corresponds to a predetermined function of the power output of said generator and of the main exciter field excitation, the output of said second control means being operably connected to said deriving means to control the gating of said controlled rectifier elements and of said deriving in response to said second control signal; and

said converting means and said deriving means each comprising a plurality of controlled rectifier elements electrically connected in a bridge arrangement, said controlled rectifier elements being connected in a positive pole relation with respect to the output circuit of said bridge to conduct positive current, when gated on, from its associated power source to said main exciter field winding.