US-12620849-B2 - Brushless alternator

US12620849B2US 12620849 B2US12620849 B2US 12620849B2US-12620849-B2

Abstract

A vehicle brushless alternator assembly that includes a claw pole rotor assembly having a pair of opposing pole pieces. The rotor defining an axis of rotation, each of the pole pieces having multiple circumferentially spaced pole fingers extending axially. The pole fingers of the rotor alternating between north and south magnetic polarities upon energization of a field coil. The assembly including a cylindrical stator including armature enveloping the magnetic claw poles, the stator arranged coaxially relative to the drive shaft. The field coil positioned relative to said rotor to generate magnetic flux and the field coil including a first field winding electrically connected with a second field winding by a switch such that: in a first operable configuration the switch operates to electrically connect the field windings in series during energization and in a second operable configuration the switch operates to electrically connect the field windings in parallel during energization.

Inventors

Mark Roberts

Assignees

Rapid Power Industries

Dates

Publication Date: 20260505
Application Date: 20211216
Priority Date: 20201217

Claims (10)

1 . A vehicle brushless alternator assembly comprising: a claw pole rotor assembly having a pair of opposing pole pieces, the rotor defining an axis of rotation, each of the pole pieces having a plurality of circumferentially spaced pole fingers extending axially, the pole fingers of the rotor alternating between north and south magnetic polarities upon energization of a field coil; and a cylindrical stator comprising an armature enveloping the magnetic claw poles, the stator arranged coaxially relative to a drive shaft; the field coil structured to be positioned coaxially in an internal cavity of said rotor to arrange the field coil in a spaced relationship relative to said rotor to generate magnetic flux upon being energized, the field coil comprising at least a first field winding electrically connected with at least a second field winding by a switching arrangement such that: in a first operable configuration the switching arrangement operates to electrically connect the first and second field windings in series during energization; and in a second operable configuration the switching arrangement operates to electrically connect the first and second field windings in parallel during energization, wherein the vehicle brushless alternator assembly further comprises sensor assembly operatively coupled to the switching arrangement for switching between the first and second operable configuration in response to sensing changes in one or more predetermined parameters.
2 . The vehicle brushless alternator assembly in accordance with claim 1 , wherein the sensor assembly comprises one or more temperature sensors such that when temperature sensed by the one or more temperature sensors exceeds a predetermined limit, the switching arrangement switches the field coil from the first operable configuration to the second operable configuration.
3 . The vehicle brushless alternator assembly in accordance with claim 2 , wherein the one or more temperature sensors are positioned within an internal volume of a housing enclosing the stator and the rotor.
4 . The vehicle brushless alternator assembly in accordance with claim 3 , wherein terminal ends of the first and second field winding terminate on a connector assembly positioned relative to the housing to allow a user to switch between the first and second operable configurations.
5 . The vehicle brushless alternator assembly in accordance with claim 4 , wherein the connector assembly comprises a plurality of electrical terminals such that: electrically connecting a set of the terminals in a first sequence results in operation of the switching arrangement in the first operable configuration; and electrically connecting a second set of the terminals in a second sequence results in operation of the switching arrangement in the second operable configuration.
6 . The vehicle brushless alternator assembly in accordance with claim 1 , wherein each of the first field winding and the second field winding provide substantially equal electrical resistance to a flow of current.
7 . The vehicle brushless alternator assembly in accordance with claim 1 , wherein at least the first field winding is electrically connected to a voltage regulator and wherein the second field winding is not electrically connected to a voltage regulator.
8 . The vehicle brushless alternator assembly in accordance with claim 1 , further comprising a housing assembly surrounding said cylindrical stator with the drive shaft being supported by the housing assembly wherein the field coil is fixedly mounted to the housing assembly.
9 . A vehicle brushless alternator assembly comprising: a claw pole rotor assembly having a pair of opposing pole pieces, the rotor defining an axis of rotation, each of the pole pieces having a plurality of circumferentially spaced pole fingers extending axially, the pole fingers of the rotor alternating between north and south magnetic polarities upon energization of a field coil; and a cylindrical stator comprising armature enveloping the magnetic claw poles, the stator arranged coaxially relative to a drive shaft; the field coil structured to be positioned coaxially in an internal cavity of said rotor to arrange the field coil in a spaced relationship relative to said rotor to generate magnetic flux upon being energized, the field coil comprising at least a first field winding electrically connected with at least a second field winding by a switching arrangement such that: in a first operable configuration the switching arrangement operates to electrically connect the first and second field windings in series during energization; and in a second operable configuration the switching arrangement operates to electrically disconnects the second field winding from the first field winding to result in energization of the first field winding without energizing the second field winding, wherein the vehicle brushless alternator assembly further comprises a sensor assembly operatively coupled to the switching arrangement for switching between the first and second operable configuration, in response to sensing changes in one or more predetermined parameters.
10 . A vehicle brushless alternator assembly comprising: a claw pole rotor assembly having a pair of opposing pole pieces, the rotor defining an axis of rotation, each of the pole pieces having a plurality of circumferentially spaced pole fingers extending axially, the pole fingers of the rotor alternating between north and south magnetic polarities upon energization of a field coil; and a cylindrical stator comprising armature enveloping the magnetic claw poles, the stator arranged coaxially relative to a drive shaft; the field coil structured to be positioned coaxially in an internal cavity of said rotor to arrange the field coil in a spaced relationship relative to said rotor to generate magnetic flux upon being energized, the field coil comprising at least a first field winding electrically connected with at least a second field winding, wherein the second field winding is electrically connected to a boost controlling module, the boost controlling module being arranged to: energize the second field winding, in a boosting mode, to increase the magnetic flux generated by the field coil; energize the second field winding in an opposite polarity relative to the first field winding, in a reductive mode, to reduce the magnetic flux generated by the field coil; and wherein the first field winding is electrically connected with the second field winding by a switching arrangement such that: in a first operable configuration the switching arrangement operates to electrically connect the first and second field windings in parallel during energization; and in a second operable configuration the switching arrangement operates to electrically connect the first and second field windings in parallel during energization, wherein the vehicle brushless alternator assembly further comprises a sensor assembly operatively coupled to the switching arrangement for switching between the first and second operable configuration, in response to sensing changes in one or more predetermined parameters.

Description

TECHNICAL FIELD The present invention relates to vehicle alternators and more particularly to brushless alternators. BACKGROUND Any references to methods, apparatus or documents of the prior art are not to be taken as constituting any evidence or admission that they formed, or form part of the common general knowledge. Most motor vehicles include an alternator that transforms mechanical energy into electrical energy that is used to charge an on-board battery. Generally, alternators fall into two categories: brushed alternators, and brushless alternators. Brushed alternators include a rotor having rotor windings that is rotated within a stator. The rotor includes a pair of slip rings that are electrically coupled to the rotor windings, that when energized create rotating magnetic fields. The slip rings are in sliding contact with stationary brushes. With this arrangement, rotation of the rotor relative to the stator passes magnetic fields through the stator winding creating a current in the stator. The current is conditioned and employed to charge a battery or support vehicle electrical loads. Brushless alternators work in the same way as brush type alternators except that there are no brushes to carry current. Brushless alternators include a main alternator and an exciter having a stationary field winding. In the exciter, the field winding creates magnetic fields in the rotor as the rotor rotates in close proximity to a large core mounted on the rotor shaft. The main alternator includes a rotor and a stationary armature or stator. Varying current through the exciter field coil varies output from the stator. The output is rectified by a stationary rectifier assembly mounted to the machine thereby creating a DC current. A portion of the DC current is passed back to the field winding to establish an alternator output. The alternator output is then employed to charge a vehicle battery or support vehicle electrical loads. One of the problems associated with creating high current in alternators (brushed and brushless) relates to overheating of internal components. Overheating is caused by many factors including but not limited to high ambient temperatures within the engine bay and insufficient movement of internal cooling air when operating at low RPMs and high electrical loads. Consequently it is desirable to provide a method and apparatus for controlling the alternator temperature in these circumstances. SUMMARY OF INVENTION In an aspect, the invention provides a vehicle brushless alternator assembly comprising: a claw pole rotor assembly having a pair of opposing pole pieces, the rotor defining an axis of rotation, each of the pole pieces having a plurality of circumferentially spaced pole fingers extending axially, the pole fingers of the rotor alternating between north and south magnetic polarities upon energization of a field coil; a cylindrical stator comprising armature enveloping the magnetic claw poles, the stator arranged coaxially relative to the drive shaft; the field coil structured to be positioned relative to said rotor to generate magnetic flux upon being energized, the field coil comprising at least a first field winding electrically connected with at least a second field winding by a switching arrangement such that: in a first operable configuration the switching arrangement operates to electrically connect the first and second field windings in series during energization and; in a second operable configuration the switching arrangement operates to electrically connect the first and second field windings in parallel during energization. In another aspect, the invention provides a vehicle brushless alternator assembly comprising: a claw pole rotor assembly having a pair of opposing pole pieces, the rotor defining an axis of rotation, each of the pole pieces having a plurality of circumferentially spaced pole fingers extending axially, the pole fingers of the rotor alternating between north and south magnetic polarities upon energization of a field coil; a cylindrical stator comprising armature enveloping the magnetic claw poles, the stator arranged coaxially relative to the drive shaft; the field coil structured to be positioned relative to said rotor to generate magnetic flux upon being energized, the field coil comprising at least a first field winding electrically connected with at least a second field winding by a switching arrangement such that: in a first operable configuration the switching arrangement operates to electrically connect the first and second field windings in series during energization and; in a second operable configuration the switching arrangement operates to electrically disconnects the second field winding from the first field winding to result in energization of the first field winding without energizing the second field winding. In an embodiment, the brushless alternator further comprises a sensor assembly operatively coupled to the switching arrangement for s