Auxiliary winding for a generator

Patent metadata

Field	Value
Publication number	US-2016013744-A1
Application number	US-201414325676-A
Country	US
Kind code	A1
Filing date	Jul 8, 2014
Priority date	Jul 8, 2014
Publication date	Jan 14, 2016
Grant date	—

Abstract

An auxiliary winding for use in an engine-driven generator system is disclosed. The auxiliary winding is separate from but resides with the main winding in the stator slots of an alternator in the generator system. The auxiliary winding is configured to utilize the fundamental component of the flux in the airgap of the alternator along with selected spatial harmonic components to provide power to an automatic voltage regulator during all operating conditions.

First claim

We claim:

1 . An alternator for a generator system, comprising:
a rotor having an excitation winding; a stator having a plurality of slots, wherein a main winding and an auxiliary winding are each wound in the plurality of slots; and an airgap defined between the stator and the rotor, wherein the auxiliary winding includes a plurality of turns of wire, each turn wound in a first direction in a first slot selected from the plurality of slots of the stator and in a second direction in a second slot selected from the plurality of slots of the stator and wherein each of the plurality of turns of wire are wound in the plurality of slots according to a distribution function, wherein the distribution function is defined to couple the auxiliary winding to a fundamental component and a desired spatial harmonic component selected from a plurality of spatial harmonic components of a magnetic flux generated in the airgap and wherein the distribution function is defined to minimize coupling of the auxiliary winding to the plurality of spatial harmonic components of the magnetic flux other than the desired spatial harmonic component.

2 . The alternator of claim 1 wherein the desired spatial harmonic component is the third harmonic.

3 . The alternator of claim 1 wherein the distribution function includes a first distribution component configured to couple the auxiliary winding to the fundamental harmonic component of the magnetic flux and a second distribution component configured to couple the auxiliary winding to the desired spatial harmonic component of the magnetic flux.

4 . The alternator of claim 3 wherein the first distribution component of the distribution function defines a magnitude corresponding to a portion of the turns of wire in each of the plurality of slots for coupling the auxiliary winding to the fundamental component of the magnetic flux and a sinusoidal function corresponding to an angular position and a number of pole pairs present in the stator.

5 . The alternator of claim 4 wherein the second distribution component of the distribution function defines a magnitude corresponding to a portion of the turns of wire in each of the plurality of slots for coupling the auxiliary winding to the desired spatial harmonic component of the magnetic flux and a sinusoidal function corresponding to the angular position, the number of pole pairs present in the stator, and the desired spatial harmonic.

6 . The alternator of claim 5 wherein the distribution function is defined by T(θ)=T 1 cos(nθ+φ 1 )+T h cos(n·h·θ+φ h ), where:
θ is the angular position,
n is the number of pole pairs,
h is the desired spatial harmonic component,
T(θ) is a number of turns as a function of the angular position,
T 1 is the magnitude of the first distribution component for coupling to the fundamental component,
T h is the magnitude of the second distribution component for coupling to the desired spatial harmonic component,
φ 1 is an angle offset for the fundamental component, and
φ h is an angle offset for the desired spatial harmonic component.

7 . A method of providing power to an excitation winding on a rotor of an alternator in a generator system with a single auxiliary winding and a main winding each wound on a stator of the alternator, wherein the stator is separated from the rotor by an airgap, the method comprising the steps of:
receiving power on the auxiliary winding corresponding to a current conducted by the excitation winding, wherein the auxiliary winding is wound on the stator to couple the auxiliary winding to a fundamental component and a desired spatial harmonic component selected from a plurality of spatial harmonic components of a magnetic flux generated in the airgap of the alternator and to minimize coupling of the auxiliary winding to the plurality of spatial harmonic components of the magnetic flux other than the desired spatial harmonic component; transmitting the power from the auxiliary winding to an automatic voltage regulator (AVR); and controlling power from the AVR to the excitation winding as a function of the output voltage of the main winding.

8 . The method of claim 7 wherein the desired spatial harmonic component is the third harmonic.

9 . The method of claim 7 wherein the auxiliary winding is wound according to a distribution function having a first distribution component configured to couple the auxiliary winding to the fundamental harmonic component of the magnetic flux and a second distribution component configured to couple the auxiliary winding to the desired spatial harmonic component of the magnetic flux.

10 . The method of claim 9 wherein the first distribution component of the distribution function defines a magnitude corresponding to a portion of the turns of wire in each of a plurality of slots in the stator for coupling the auxiliary winding to the fundamental component of the magnetic flux and a sinusoidal function corresponding to an angular position and a number of pole pairs present in the stator.

11 . The method of claim 10 wherein the second distribution component of the distribution function defines a magnitude corresponding to a portion of the turns of wire in each of the plurality of slots for coupling the auxiliary winding to the desired spatial harmonic component of the magnetic flux and a sinusoidal function corresponding to the angular position, the number of pole pairs present in the stator, and the desired spatial harmonic.

12 . An alternator configured to be driven by an engine in an engine-driven generator system, the alternator comprising:
a stator, including:
a plurality of slots,
a main winding distributed in the plurality of slots, and
an auxiliary winding distributed in the plurality of slots according to a distribution function, wherein the distribution function defines a distribution of the auxiliary winding in the slots of the stator in order to couple the auxiliary winding to a fundamental component and a desired spatial harmonic component of a magnetic flux generated in an airgap of the alternator and to minimize coupling of the auxiliary winding to other spatial harmonic components of the magnetic flux;
a rotor, rotatably mounted within the stator and driven by the engine, the rotor including an excitation winding configured to conduct a current which establishes the magnetic flux in the airgap; and an automatic voltage regulator (AVR) controlling the current in the rotor as a function of at least one of a current and a voltage present on the main winding.

13 . The alternator of claim 12 wherein the desired spatial harmonic component is the third harmonic.

14 . The alternator of claim 12 wherein the AVR includes a power section including:
an input electrically connected to the auxiliary winding,
an output electrically connected to the excitation winding, and
a plurality of switches selectively connecting the input to the output.

15 . The alternator of claim 12 wherein the AVR includes a power section including:
an input electrically connected to the auxiliary winding,
an output electrically connected to the excitation winding,
a rectifier section electrically connected to the input and configured to convert an alternating current (AC) voltage at the input to a direct current (DC) voltage at a first DC voltage potential, and
a converter section electrically connected between the rectifier section and the output and configured to convert the DC voltage at the first DC voltage potential to one of a DC voltage at a second voltage potential and an AC voltage at the output.

16 . Th

Assignees

• Generac Power Systems Inc

Inventors

• Mclean Graham W

Classifications

• H02K3/12

  arranged in slots · CPC title

• H02K3/28

  Layout of windings or of connections between windings (windings for pole-changing H02K17/06, H02K17/14, H02K19/12, H02K19/32) · CPC title

• H02K7/1815

  structurally associated with reciprocating piston engines (general aspects of generating sets, e.g. housing, F02B63/04) · CPC title

• H02P9/38 Primary

  Self-excitation by current derived from rectification of both output voltage and output current of generator · CPC title

• H02K19/34 Primary

  Generators with two or more outputs · CPC title