Hybrid alternator

• US 5,753,989 A
• Filed: 03/31/1995
• Issued: 05/19/1998
• Est. Priority Date: 06/14/1993
• Status: Expired due to Fees

• Current Assignee: Ecoair Corp.
• Original Assignee: Ecoair Corp.
• Inventors: Syverson, Charles D., Curtiss, William P.
• Primary Examiner(s): Stephan, Steven L.
• Assistant Examiner(s): WALLACE, MICHAEL J
• Application Number:
  US08/414,350
• Time in Patent Office: 1,145 Days
• Field of Search: 310/114, 310/263, 310/261, 310/181, 310/156, 310/42, 310/15, 322/28, 322/29, 322/46
• US Class Current: 310/114
• CPC Class Codes: B60L 50/15 with additional electric power supply with capacitors charged by engine-driven generators B60L50/40; with batteries charged by engine-driven generators B60L50/61
• CPC Class Codes: H02H 5/042 using temperature dependent resistors
• CPC Class Codes: H02H 7/06 for dynamo-electric generators; for synchronous capacitors
• CPC Class Codes: H02H 7/067 on occurrence of a load dump control on sudden change of load H02P9/10
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H02J 7/1423 with multiple batteries
• CPC Class Codes: H02J 7/1438 in combination with power supplies for loads other than batteries
• CPC Class Codes: H02J 7/163 with special means for initiating or limiting the excitation current
• CPC Class Codes: H02J 7/28 using magnetic devices with controllable degree of saturation in combination with controlled discharge tube or controlled semiconductor device
• CPC Class Codes: H02K 1/24 Rotor cores with salient poles ; Variable reluctance rotors
• CPC Class Codes: H02K 1/2713 the magnetisation axis of the magnets being axial, e.g. claw-pole type
• CPC Class Codes: H02K 1/276 Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]
• CPC Class Codes: H02K 1/2773 consisting of tangentially magnetized radial magnets
• CPC Class Codes: H02K 16/00 Machines with more than one rotor or stator machines for transmitting mechanical power from a driving shaft to a driven shaft and comprising structurally interrelated motor and generator parts H02K51/00; permanent magnet machines with multiple rotors or stators relatively rotated for vectorially combining the excitation fields or the armature voltages H02K21/029
• CPC Class Codes: H02K 19/103 Motors having windings on the stator and a variable reluctance soft-iron rotor without windings
• CPC Class Codes: H02K 19/28 for self-excitation
• CPC Class Codes: H02K 19/36 Structural association of synchronous generators with auxiliary electric devices influencing the characteristic of the generator or controlling the generator, e.g. with impedances or switches
• CPC Class Codes: H02K 19/365 with a voltage regulator
• CPC Class Codes: H02K 21/042 : with permanent magnets and field winding both rotating
• CPC Class Codes: H02K 3/51 : applicable to rotors only
• CPC Class Codes: H02K 9/06 : with fans or impellers driven by the machine shaft
• CPC Class Codes: H02P 2101/45 : for motor vehicles, e.g. car alternators
• CPC Class Codes: H02P 9/006 : Means for protecting the generator by using control H02H7/06 takes precedence; control effected upon generator excitation circuit to reduce harmful effects of overloads or transients H02P9/10
• CPC Class Codes: H02P 9/305 : controlling voltage H02P9/302 takes precedence
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors

Abstract

A hybrid alternator comprising a stator, and a rotor mounted for rotation within the stator and separated therefrom by an air gap, said rotor having a rotor core defining a plurality of magnetic poles, adjacent ones of the magnetic poles having alternating north and south magnetic fields, the plurality of magnetic poles comprising at least one permanent magnetic pole defined by a permanent magnet, and a plurality of electromagnetic poles, each of which is defined by a wound field.

Claims

1. A hybrid alternator comprising:

a stator; and

a rotor mounted for rotation within the stator and separated therefrom by an air gap, said rotor having a rotor core defining a plurality of magnetic poles, adjacent ones of the magnetic poles having alternating north and south magnetic fields, the plurality of magnetic poles being consecutively arranged in a direction that is circumferential of the rotor core at least one of the magnetic poles being a permanent magnetic pole including a permanent magnet, the remaining magnetic poles comprising a plurality of electromagnetic poles, each electromagnetic pole including a winding, the permanent magnet of the permanent magnetic pole being physically remote from each of the windings of the electromagnetic poles.

2. The hybrid alternator of claim 1 wherein said rotor core defines a plurality of rotor field poles, each of which being associated with a corresponding magnetic pole.

3. The hybrid alternator of claim 2 wherein said permanent magnet is attached to a corresponding rotor field pole to form the permanent magnetic pole.

4. The hybrid alternator of claim 3 wherein said magnet is attached to the rotor field pole in a manner such that said magnet forms a portion of the rotor perimeter.

5. The hybrid alternator of claim 3 wherein the rotor field pole associated with said permanent magnetic pole includes a rotor field pole shoe, said magnet being positioned between said rotor core and said rotor field pole shoe.

6. The hybrid alternator of claim 2 further including at least one permanent magnet, said magnet being positioned within the rotor perimeter and associated with a pair of adjacent rotor field poles to form adjacent permanent magnet poles, said magnet being magnetically isolated from said rotor core.

7. The hybrid alternator of claim 6 wherein said magnet is formed from a magnetic material chosen from ferrite, neodymium, ceramic and samarium-cobalt.

8. The hybrid alternator of claim 2 wherein each rotor field pole has a longitudinal axis substantially parallel to the rotor rotationial axis, each of said rotor field poles radially extending from said rotor core, said rotor field pole comprising:

a body portion radially extending from said core to an end surface and having a first longitudinal length, and

an end portion attached to said end surface and having a second longitudinal length that is greater than said first longitudinal length.

9. The hybrid alternator of claim 1 wherein the permanent magnet is arranged in a manner such that the direction of magnetization is oriented radially relative to the rotor core rotational axis.

10. The hybrid alternator of claim 6 wherein the permanent magnet is arranged in a manner such that the direction of magnetization is oriented circumferentially relative to the rotor core rotational axis.

11. The hybrid alternator of claim 2 wherein the rotor core is a salient pole rotor core.

12. The hybrid alternator of claim 11 wherein the salient pole rotor core is comprised of a plurality of laminations stacked together and arranged perpendicular to the rotor core rotational axis.

13. The hybrid alternator of claim 12 wherein the plurality of laminations define a plurality of radially extending projections that form the plurality of rotor field poles.

14. The hybrid of alternator of claim 1 wherein the plurality of magnetic poles comprises ten (10) magnetic poles.

15. The hybrid of alternator of claim 14 wherein two (2) of the magnetic poles are permanent magnetic poles and the remaining magnetic poles are electromagnetic poles.

16. The hybrid alternator of claim 15 wherein the two (2) of the permanent magnet poles are diametrically positioned with respect to one another.

17. The hybrid alternator according to claim 1 further comprising a rotor excitation circuit connected to the rotor winding in the wound field rotor portion for producing a forward excitation current through the rotor winding to increase output from the alternator in a boosting mode and a reverse excitation current through the rotor winding to decrease output from the alternator in a bucking mode.

18. The hybrid alternator according to claim 17 wherein the rotor excitation circuit controls the forward and reverse excitation currents by pulse width modulation.

19. The hybrid alternator according to claim 17 wherein the rotor excitation circuit is connected to monitor an output voltage from the stator winding and produces the forward excitation current in the rotor winding when the output voltage is below a desired level and produces the reverse excitation current in the rotor winding when the output voltage is above the desired level.

20. The hybrid alternator according to claim 17 in combination with a voltage converter circuit, the voltage converter circuit having an input receiving a generated voltage from the stator winding and an output producing a voltage less than the generated voltage from the stator winding.

21. The hybrid alternator according to claim 20 wherein the input of the voltage converter circuit is connected directly to the stator winding.

22. The hybrid alternator according to claim 20 wherein the input of the voltage converter circuit is connected to a rectified output voltage from the stator winding.

23. The hybrid alternator of claim 1 wherein the wound fields include a rotor winding, the hybrid alternator further includes a voltage regulator for controlling bidirectional current flow through a winding of an alternator to control an output voltage of the alternator, the voltage regulator comprising:

a voltage monitoring circuit connected to monitor the output voltage of the alternator, the voltage monitoring circuit producing an error signal indicating that the output voltage of the alternator should be increased or decreased;

a switching circuit connected to the winding and arranged to connect the winding in multiple modes, including;

a forward polarity mode in which a forward polarity voltage is applied to the winding,

a reverse polarity mode in which a reverse polarity voltage is applied to the winding, and

a decay mode in which current induced in the winding when connected in the forward or reverse polarity mode is permitted to decay without inducing damaging voltages in the voltage regulator; and

a control circuit connected to the switching circuit responsive to the error signal of the monitoring circuit, the control circuit controlling the switching circuit to enter the forward polarity mode to increase the output voltage of the alternator, to enter the reverse polarity mode to decrease the output voltage of the alternator and to enter the decay mode whenever switching away from the forward or reverse polarity mode.

24. The hybrid alternator of claim 1 wherein said permanent magnetic pole defines a permanent magnetic flux field, said stator includes a stator winding having a neutral point voltage, and said wound field includes a rotor winding having a first end connected to the neutral point on the stator winding and a second end adapted for connection to a switching circuit in a voltage regulator, the wound fields producing a rotor wound magnetic flux field that additively combines with the permanent magnetic flux field when the switching circuit connects the second end to a voltage greater than the neutral point voltage and producing a rotor magnetic flux field that subtractively combines with the permanent magnetic flux field when the switching circuit connects the second end to a voltage less than the neutral point voltage.

25. A hybrid alternator comprising:

a stator having a stator winding;

a rotor mounted for rotation within the stator and separated therefrom by an air gap,

the rotor including;

a rotor core defining a plurality of rotor field poles,

at least one permanent magnet, the magnet being attached to a corresponding rotor field pole to define a permanent magnetic pole, the magnet being attached in a manner such that it forms a portion of the rotor perimeter, and

a rotor winding wound only around the remaining rotor field poles to define a plurality of electromagnetic poles, the permanent magnetic pole being physically remote from the rotor winding on the remaining rotor field poles, the electromagnetic and permanent magnetic poles being consecutively arranged in a direction that is circumferential of the rotor core, adjacent ones of the magnetic poles having alternating north and south magnetic fields.

26. A hybrid alternator comprising:

a stator having a stator winding;

a rotor mounted for rotation within the stator and separated therefrom by an air gap,

the rotor including;

a rotor core defining a plurality of rotor field poles,

at least one permanent magnet, the magnet being positioned within the rotor perimeter and associated with a pair of adjacent rotor field poles to form adjacent permanent magnetic poles, and

a rotor winding wound only around the remaining rotor field poles to define a plurality of electromagnetic poles, the permanent magnetic being physically remote from the rotor winding on the remaining rotor field poles, the electromagnetic and permanent magnetic poles being consecutively arranged in a direction that is circumferential of the rotor core, adjacent ones of the magnetic poles having alternating north and south magnetic fields.

27. A hybrid alternator comprising:

a stator having a stator winding;

a rotor mounted for rotation within the stator and separated therefrom by an air gap,

the rotor including;

a rotor core defining a plurality of rotor field poles, each of which having a pole shoe,

at least one permanent magnet, the magnet being mounted between the rotor core and said pole shoe to form a permanent magnetic pole, and

a rotor winding wound only around the remaining rotor field poles to define a plurality of electromagnetic poles, the permanent magnetic being physically remote from the rotor winding on the remaining rotor field poles, the electromagnetic and permanent magnetic poles being consecutively arranged in a direction that is circumferential of the rotor core, adjacent ones of the magnetic poles having alternating north and south magnetic fields.

28. A hybrid alternator comprising:

a rotor core mounted for rotation within the stator and separated therefrom by a radial air gap, the rotor including;

a shaft mounted for rotation within the stator,

a wound field rotor portion mounted on the shaft for rotation within a first longitudinal region of the stator, the wound field rotor portion having a rotor winding and multiple electromagnet poles, each of said electromagnetic poles includes a rotor field pole having a longitudinal axis substantially parallel to said shaft, said rotor field pole includes;

a body portion radially extending from said rotor core to an end surface and having a first longitudinal length, and

an end portion attached to said end surface and having a second longitudinal length that is greater than said first longitudinal length and

a permanent magnet rotor portion mounted on the shaft in longitudinally spaced relation to the wound field rotor portion for rotation within a second longitudinal region of the stator, the permanent magnet rotor portion having multiple permanent magnetic poles.

29. A hybrid alternator comprising:

a stator; and

a rotor mounted for rotation within the stator and separated therefrom by an air gap, said rotor having a rotor core having a plurality of rotor field poles that define a rotor perimeter, each rotor field pole defining a corresponding magnetic pole, adjacent ones of the magnetic poles having alternating north and south magnetic fields, the magnetic poles being consecutively arranged in a direction that is circumferential of the rotor core, at least one of the magnetic poles being a permanent magnetic pole comprising a permanent magnet positioned on the rotor and within the rotor perimeter, the remaining magnetic poles comprising a plurality of electromagnetic poles, each electromagnetic pole including a winding, the permanent magnet of the permanent magnetic pole being physically remote from each of the windings of the electromagnetic poles.

30. A hybrid alternator comprising:

a stator; and

a rotor mounted for rotation within the stator and separated therefrom by an air gap, said rotor having a rotor core having a plurality of rotor field poles that define a rotor perimeter, each rotor field pole defining a corresponding magnetic pole, adjacent ones of the magnetic poles having alternating north and south magnetic fields, the magnetic poles being consecutively arranged in a direction that is circumferential of the rotor core, at least one of the magnetic poles being a permanent magnetic pole comprising a permanent magnet that is attached to one of the rotor field poles and forms a portion of the rotor perimeter, the remaining magnetic poles comprising a plurality of electromagnetic poles, each electromagnetic pole including a winding, substantially all of the flux of at least one magnetic pole being derived from the permanent magnet, the flux of at least one of the remaining magnetic poles being derived from the windings of the electromagnetic poles, the permanent magnet of the permanent magnetic pole being physically remote from each of the windings of the electromagnetic poles.

31. A hybrid alternator comprising:

a stator; and

a rotor mounted for rotation within the stator and separated therefrom by an air gap, said rotor having a rotor core having a plurality of rotor field poles that define a rotor perimeter, each rotor field pole defining a corresponding magnetic pole, adjacent ones of the magnetic poles having alternating north and south magnetic fields, the magnetic poles being consecutively arranged in a direction that is circumferential of the rotor core, at least one of the magnetic poles being a permanent magnetic pole comprising a permanent magnet that is positioned within the rotor perimeter and associated with a pair of adjacent rotor field poles to form adjacent permanent magnet poles, the remaining magnetic poles comprising a plurality of electromagnetic poles, each electromagnetic pole including a winding, at least two of the magnetic poles having a flux derived from the permanent magnet and the winding of an adjacent magnetic pole, substantially all of the flux of each remaining magnetic pole being derived from the windings of the electromagnetic poles, the permanent magnetic of the permanent magnetic pole being physically remote from each of the windings of the electromagnetic poles.