BROAD-SPEED-RANGE GENERATOR VARIATIONS

• US 20120256422A1
• Filed: 04/05/2011
• Published: 10/11/2012
• Est. Priority Date: 04/05/2011
• Status: Abandoned Application

• Current Assignee: Richard B. Fradella
• Original Assignee: Richard B. Fradella
• Inventors: Fradella, Richard B.
• Application Number:
  US13/080,488
• Publication Number:
  US 20120256422A1
• Time in Patent Office: Days
• US Class Current: 290/55
• CPC Class Codes: H02K 1/2796 where both axial sides of the rotor face a stator
• CPC Class Codes: H02K 21/24 with magnets axially facing the armatures, e.g. hub-type cycle dynamos
• CPC Class Codes: H02K 3/47 Air-gap windings, i.e. iron-free windings
• CPC Class Codes: H02K 7/183 wherein the turbine is a wind turbine adaptation of a wind turbine to an electric generator F03D9/25
• CPC Class Codes: H02K 7/1838 Generators mounted in a nacelle or similar structure of a horizontal axis wind turbine
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction

Abstract

A brushless generator with permanent-magnet multi-pole rotor disks and stator winding disks in their axial magnetic field includes integral electronics to efficiently generate regulated DC current and voltage from mechanical input power over a broad speed range. All power for the electronics is provided by rectifier diodes from its stator windings. Differential amplifiers provide stator voltage feedback signals. Its power rating is scalable, depending on the number of its disks. Having no iron cores and no gears, it incurs no cogging torque, and no gear friction. Integral power control electronics includes high-frequency pulse-width-modulated boost regulation, which provides regulated current at requisite voltage over its broad speed range. A main wind-powered embodiment to produce DC power for a constant voltage DC load over a broad speed range includes signal processing so output power varies according to the third power of speed. Combined boost-regulation, zero cogging torque, and no gearing, enable a wide speed range, for better power quality and higher wind energy yields.

Claims

1. A generator, including a coreless stator and rotor assembly, and integral power control electronics, for producing regulated DC current and voltage, from mechanical input power, over a broad range of shaft speeds, comprising:

stator disks holding poly-phase stator windings in a non-conductive non-magnetic matrix, axially juxtaposed with abutting conductor insulation, said windings angularly juxtaposed relative to each other 180°

divided by the number of poles, said disks angularly aligned with a selectable number of like disks, that each produce across their windings a substantially sinusoidal voltage having amplitude and frequency proportional to rotational speed;

rotor disks holding a plurality of axially-magnetized alternating pole permanent-magnets, attached therein in a symmetrical circular array around an axis of rotation, said rotor disks angularly aligned with a selectable number of like disks numbering one more than the number of stator disks, the axial magnetic field from the rotor disks at the stator varying substantially sinusoidally with rotor angle;

differential amplifiers, responsive to the voltage across respective stator windings, to provide respective feedback of stator voltage for integral power control electronics; and

integral power control electronics, supplied by rectifier diodes from the stator windings, the electronics responsive to the stator voltage feedback signals from the differential amplifiers, and to a DC output voltage feedback signal, and to user settings, and to stator winding current feedback signals, for controlling current through the stator windings by high-frequency pulse-width-modulation, to provide DC power by filtered high-frequency boost-regulation, having regulated current and voltage, for a DC load, from mechanical power, over a broad range of speeds.

2. The generator of claim 1, wherein said integral power electronics in a generator embodiment intended to produce regulated DC current and voltage from wind turbines, with output power proportional to the third power of speed, over a broad speed range, further comprises:

means to compare a reference voltage setting with rectified DC voltage equal to DC output load voltage, and to provide a corrective signal if the reference setting is exceeded;

means to provide from sinusoidal and cosinusoidal stator voltage feedback signals, a signal having average amplitude proportional to rotor speed;

means to process the sinusoidal and cosinusoidal stator voltage feedback signals to provide their absolute values, and to multiply the respective absolute values by the average amplitude signal, for providing respective stator current command signals;

means to sense and process over a wide dynamic range, respective stator winding currents, to obtain respective stator winding current absolute values;

means to compare the respective stator current command signals, with the stator winding current signals, to provide respective PWM stator current control; and

over-voltage protection means, to inhibit PWM stator current output if DC output voltage exceeds a prescribed level.

3. The generator of claim 1, wherein said integral power control electronics in a generator embodiment intended to generate electric power from varied mechanical shaft power sources further comprises:

means to compare a reference setting level with DC voltage feedback, and to provide a corrective signal therefrom if the reference setting is exceeded;

means to compare said corrective signal with an effort level selection, to provide an effort level signal that optimizes generator output without exceeding the reference setting;

means to process the stator voltage sensor signals, to provide their respective absolute values, and to multiply the respective absolute values by the effort level signal, for providing respective stator current command signals;

means to sense and process over a wide dynamic range, respective stator winding feedback currents, to obtain respective stator winding current absolute value signals;

means to compare the respective stator current command signals, with the current absolute values, to provide respective PWM stator current control; and

over-voltage protection means, to inhibit PWM stator current output if DC output voltage exceeds a prescribed level.

4. The generator of claim 1, wherein said coreless stator and rotor generator assembly further comprises a vertical rotation axis and relatively large diameter, containing a plurality of rotor disks holding a relatively high number of poles intended to obviate speed-up gearing, to generate regulated DC current and voltage, over a wide speed range partly enabled by its zero cogging torque and absence of gear friction, from vertical-axis wind turbine shaft power.

5. The generator of claim 1, wherein said coreless stator and rotor generator assembly further comprises a horizontal rotation axis, to generate regulated DC current and voltage over a wide speed range partly enabled by its zero cogging torque and absence of gear friction, from horizontal-axis wind turbine shaft power.

6. The generator of claim 1, wherein said rotor disks further comprise axially magnetized permanent-magnets having contours to provide nearly sinusoidal flux variation with rotor angle, for the stator winding radial segments.

7. The generator of claim 1, wherein said coreless stator and rotor generator assembly further comprises stator disks having an electrically non-conducting matrix that is thermally conductive, to transfer heat from stator winding copper loss to the generator assembly outer diameter.

8. The generator of claim 1, including the electronics of claim 2, further comprising sliding brake surface means to limit shaft speed when otherwise not limited by a wind turbine coupled to its shaft, to provide continued regulated output power from the generator, during high winds that would otherwise result in shaft speeds beyond the generator regulated voltage range.

9. The generator of claim 1, further comprising at least one buck regulator in series with its DC output, to provide various regulated DC output voltages.

10. The generator of claim 1, further comprising a 3-phase inverter in series with its output, to provide regulated 3-phase power with minimal distortion and selectable phase.

11. The generator of claim 1, in further combination with a wind turbine having a shaft coupled to drive said generator, wherein a selectable number of rotor and stator disks is matched to said wind turbine, to optimize the wind turbine load for producing maximum generated electric power over a broad wind speed range.

12. The generator of claim 1, in further combination with a water turbine coupled to drive said generator, wherein said selectable number of rotor and stator disks is matched to said water turbine, to optimize the water turbine load for maximum generated power.

13. The generator of claim 1, in further combination with pedals to drive its shaft, installed in an electric vehicle, to provide a battery charger and recumbent cycling exercise option in the vehicle, that also extends the vehicle driving range.

14. The generator of claim 1, further comprising an iron disk at one end of the rotor disks and another iron disk at the opposite end, to provide return flux paths for the axial-field rotor magnets therebetween.

15. The generator of claim 1, further comprising a multi-pole magnetized disk at one end of the rotor disks and another multi-pole magnetized disk at the opposite end, to provide continuous axial and tangential flux path rotor magnets at each end, for an ironless generator embodiment.

16. The generator of claim 1, wherein its rotor disks are attached to a rotatable shaft coupled to its driver, the shaft supported by two ball bearings, its stator disks extending to its outer diameter from which its stator conductor terminals are accessed from a channel in its outer diameter.

17. The generator of claim 1, wherein its rotor disks extend to its outer diameter, and its stator disks are attached to a non-rotating tubular shaft from which the stator conductor terminals are accessed, the rotor assembly supported by a pair of ball bearings, one between the shaft at a first rotor end disk and the other between the shaft and the opposite end disk.