US20150015354A1

US20150015354A1 - Halbach array electromagnet with substantially contiguous vertical and horizontal cores

Info

Publication number: US20150015354A1
Application number: US13/941,833
Authority: US
Inventors: Roberto Sanchez Catalan
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-07-15
Filing date: 2013-07-15
Publication date: 2015-01-15
Also published as: US9558876B2; US20160225507A1

Abstract

Electromagnetic Halbach array device with substantially contiguous vertical and horizontal cores, comprised of a plurality of horizontal and vertical electromagnets arranged in a Halbach array sequence, where each individual core of every horizontal electromagnet in said Halbach array is equipped with a plurality of fork-like prongs at each end, and where the magnetic coils that surround each individual core of every vertical electromagnet in said Halbach array have gaps where said fork-like prongs are positioned to provide direct physical contact between cores.

Description

FEDERALLY SPONSORED RESEARCH

Not applicable

SEQUENCE LISTING OR PROGRAM

Not applicable

BACKGROUND

1. Field of Invention
This invention relates to a novel Halbach array electromagnet with substantially contiguous vertical and horizontal cores. In very simplified terms, a Halbach array effect can be visualized as elastic looping streams of magnetic force emanating like fountains from the poles of the magnets in the array, where sets of three adjacent, similar poles magnify the fountains of magnetic force on one side of the array while elastically decreasing or cancelling the fountains on the opposite side of the array, which only have alternating north and south poles.
Permanent magnets are singular, inherently magnetized polar structures, as such they are relatively easy to orient and assemble in the prescribed sequence to enable the Halbach array effect. Electromagnets however, are structurally and functionally different from permanent magnets since they are comprised of two elements, an energized magnetic coil and an artificially magnetized core segment or tooth (hereinafter referred to as vertical or horizontal core or cores for simplicity).
Merely orienting and assembling electromagnets in a Halbach array sequence does not generally enable a useful Halbach array effect, since the magnetic coils surrounding the vertical core acts as a physical and energized barrier that prevents direct contact with the horizontal core.
Without substantial contiguity between cores, the Halbach array effect can be diminished or even negated, resulting in an ordinary, unenhanced electromagnet.
2. Description of Prior Art
In prior art most closely resembling but fundamentally different from the present invention, the electromagnets used are merely oriented and arranged as Halbach arrays, but there is no provision for establishing direct physical connectivity between the vertical and horizontal cores. The magnetic coils act as a barrier that isolates the two cores, which severely decreases or even negates the Halbach array effect to the point that it generally results in an ordinary unenhanced electromagnet. This is similar to U.S. Pat. No. 7,598,646 which presents electromagnets merely arranged in Halbach array sequence but whose vertical and horizontal cores are clearly isolated by the magnetic coils in the drawings and the description. As such it does not offer substantial contiguity between cores to ensure the direct transfer of flux necessary to guarantee the proper generation of the Halbach array effect, in sharp contrast to the present invention. As such it is fundamentally different and likely far less effective, less efficient and less controllable than the present invention. Likewise, U.S. Pat. No. 7,541,813 is an application for oil drilling, where the cylindrical electromagnets used do not provide contiguous cores, as indicated by the drawings provided. This is also the case of U.S. Pat. No. 5,705,902 which uses Halbach arrays within a generator but there is clearly no contiguity between its octagonal cores.
Most prior art that supposedly offer Halbach array electric motors only have permanent magnets arranged as Halbach arrays, however the electromagnets used are ordinary, standard, non-Halbach configurations. This is the case of U.S. Pat. No. 7,352,096 where two permanent magnet Halbach arrays on two backing plates sandwich a three phase non-Halbach array stator that uses Litz wire winding, and is thus fundamentally different from the present invention. This is also the case for U.S. Pat. No. 8,183,731 discloses a generator that uses permanent magnets mounted on discs and spaced so far apart that it is unlikely to have a strong Halbach array effect. The single reversing electromagnet detail drawing provided clearly does not pertain to a Halbach array and is thus different from the present invention. Likewise, U.S. Pat. Nos. 7,540,004, 7,031,116, 6,906,446, 6,841,910 and 6,858,962 discloses permanent magnet Halbach arrays on the rotor, but the electromagnetic stator is also non-Halbach, or not an electromagnet, and requiring a separate non-Halbach commercially available drive motor. As such, they are all fundamentally different from the present invention.
U.S. Pat. No. 8,264,314 discloses how to arrange a set of permanent magnets to increase magnetic flux. The same is true with U.S. Pat. No. 8,009,001 which discloses ‘hyper’ Halbach permanent magnet arrays. Both do not disclose Halbach array electromagnets and is thus a different category from the present invention.

OBJECTS AND ADVANTAGES

Several objects and advantages of the present invention are:

- a) to provide a Halbach array electromagnet with substantially contiguous vertical and horizontal cores that closely replicates permanent magnet Halbach arrays to maximize its effectiveness;
- b.) to harness the magnified and directed nature of Halbach array forces to increase the efficiency of electric motors that utilizes Halbach array electromagnets as one of its components, potentially enabling more powerful motors of the same size or smaller motors with the same power;
- c.) to reduce the weight of an electric motor that utilizes Halbach array electromagnets by harnessing the magnified magnetic forces inherent in Halbach arrays, and by removing the need for metal back plates that would normally be required to complete the non-Halbach electromagnet's circuit;
- d.) to enable the opportunity to switch or use both sides of a Halbach array electromagnet for various applications such as pumps, actuators, transmissions, rechargers, etc; and
- e.) to provide more efficient and controllable Halbach array electromagnets equipped with substantially contiguous cores, to replace permanent magnets in various applications or devices.

Further objects and advantages shall become apparent after considering the ensuing descriptions and drawings.

SUMMARY

The present invention solves a long existing and yet long unresolved need for substantial contiguity between the horizontal and vertical cores of a Halbach array electromagnet to maximize the efficiency of electric motors and other electromagnetic applications that aim to harness the magnified and directed magnetic forces generated by the Halbach array effect. Newer electric motors and other devices designed to integrate the present invention can either generate more power for the same amount of energy consumed, or provide the same amount of power while consuming significantly less energy. The present invention also enables a finer degree of control than prior art.

DRAWINGS Drawing Figures

In the drawings, closely related figures have the same number but different alphabetic suffixes.

FIG. 1A is a close up view of an axial Halbach array electromagnet with substantially contiguous cores. It highlights how the fork-like prongs of the horizontal electromagnet's core slips through gaps in the vertical electromagnet's magnetic coils to achieve direct and maximal flux transfer between vertical and horizontal cores to generate a strongest possible Halbach array effect.

FIG. 1B shows an overview of the sequence and orientation of vertical and horizontal electromagnets in an inner axial Halbach array used as a stator mounted on a central hub. It also shows the origin of the close up view in FIG. 1A. Note that the outer ring is likewise a Halbach array, but it is comprised of permanent magnets that are embedded into the alloy wheel of a car (not shown) to serve as a rotor. The permanent magnets and the central hub are not part of the present invention. It is only included to illustrate one possible application for the present invention, in this case as a component of an electric motor.

FIG. 2 shows a sample wiring layout for an inner axial Halbach array electromagnet in FIG. 1B, which will be used for both vertical and horizontal electromagnetic cores.

FIG. 3A shows permanent magnets arranged as Halbach arrays, with an approximation of the contrasting height of magnetic flux it produces. The drawing highlights the ‘flux aperture’ of each set of three adjacent similar magnetic poles which combine to magnify flux on one side while elastically decreasing or cancelling the magnetic flux on the other side of the Halbach array, which only has alternating north and south poles. This figure does not include any part of the present invention and is thus provided only for completeness. Straight lines were chosen to identify the flux aperture for clarity. This drawing is directly comparable to the next two figures, to emphasize significant differences between permanent magnets, prior art non-contiguous electromagnets merely arranged in Halbach sequence, and true contiguous core Halbach array electromagnets of the present invention.

FIG. 3B is oriented for direct comparison with FIG. 3A, but now showing a cut-away view of electromagnets that are merely arranged in a Halbach array sequence, with magnetic coils acting as a physical and active barrier preventing contiguity between cores. It also shows that there is no ‘flux aperture’ whatsoever to connect the sets of similar poles (in a manner similar to FIG. 3A), significantly diminishing the transfer of flux needed to generate the Halbach array effect. This figure is does not embody the present invention and is only provided for completeness, to discuss the shortcomings of prior art.

FIG. 4 shows a cut-away, close-up view of a linear, dual-sided Halbach array electromagnet, as another embodiment of the present invention, still oriented for direct comparison with FIG. 3A and FIG. 3B. It shows how the fork-like prongs re-establish the required ‘flux aperture’, penetrating the vertical core's magnetic coils to achieve substantial contiguity between cores, maximizing flux transfer to generate the strongest possible Halbach array effect in electromagnets. The octagonal shapes represent just one example for the location of attachment points, but for the sake of clarity, other attachment locations or attachment structures were not shown.

FIG. 5 shows how an inner axial Halbach array electromagnet with contiguous cores (originally shown in FIG. 1B) is used as a stator mounted to a central hub, for use in an electric motor. The outer Halbach array is the rotor that utilizes permanent magnets, which are affixed on the inner rim of a car's alloy wheel (not shown). The two sets of integrated three-phase wires that result from winding in FIG. 2 (detail not shown, but seen clearly in FIG. 1A) is connected to a three-phase DC controller (shown), which is then connected to other similarly off-the-shelf components for powering an electric vehicle. This simplified, sample diagram contains various items which are not part of the present invention and is thus only provided for completeness.

REFERENCE NUMERALS IN DRAWINGS

101 Vertical electromagnets of a Halbach array
102 Horizontal electromagnets of a Halbach array
103 Vertical electromagnet core or tooth
104 Horizontal electromagnet core or tooth
105 Magnetic coil surrounding vertical electromagnets
106 Magnetic coil surrounding horizontal electromagnets
107 Fork like prongs at the ends of each core or tooth of every horizontal electromagnet
108 Three-phase wires from magnetic coils for connection to the controller
109 Flux aperture between similar adjacent magnetic poles in a Halbach array

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The preferred embodiment of the present invention is achieved by integrating a set of horizontal electromagnets 102 between a set of vertical electromagnets 101, and arranging both in the prescribed Halbach array sequence, an example of which is shown in FIG. 1B, but ensuring that the individual cores of both horizontal 104 and vertical electromagnets 103 must be substantially contiguous as described in the next paragraph. This novel Halbach array electromagnet with substantially contiguous vertical and horizontal cores can be implemented as axial, linear, or other configurations for a multitude of applications, such as stators or rotors for electric motors.
The Halbach array sequence and orientation causes the magnetic coils surrounding the vertical electromagnets 105 to ordinarily become physical and active barriers that separate the individual cores or teeth of the horizontal 104 and vertical electromagnets 103. The present invention overcomes this barrier by introducing fork like prongs at the ends of each core or tooth of every horizontal electromagnet 107 through gaps made during the winding of aforementioned magnetic coil. Examples of contiguous core Halbach array electromagnets are in FIG. 1A (axial configuration) and FIG. 4 (linear dual-sided configuration).
Because the process of winding may damage the film of insulation covering the magnetic coil surrounding the vertical electromagnets 105, the use of optional insulating slot paper (not shown) such as that made from Nomex ™ and Mylar ™ is recommended. Since the magnetic coil surrounding the horizontal electromagnet 106 generally does not interfere with assembly, it can be wound prior to, or after insertion.

Alternative Embodiments

One alternative embodiment of form rather than function is driven by convenience in manufacturing and assembly. It primarily uses modular stator or rotor core segments to facilitate automated winding, which are pre-configured to embed insulation and gaps in the magnetic coils. This will be mated to a similarly modularized pre-wound horizontal core that is equipped with fork like prongs at each end to provide substantial contiguity between vertical and horizontal cores. This strategy will likely yield the quickest assembly times compared to other options.
With 3D metal deposition printing, it is possible to create a mesh of embedded electromagnets whereby each element of the core and coil can be multiplied, miniaturized and meshed into Halbach arrays with contiguous cores. One exciting aspect would be spherical, helical or octagonal Halbach arrays with contiguous cores for experiments in energy and other applications, which was heretofore impossible before the advent of 3D printing. Possible variations of the present invention have thus broadened considerably.

Operation—Preferred Embodiment

Since there are a multitude of applications that can benefit from Halbach array electromagnets that offer substantially contiguous cores, it would be impossible to cover all of the possible permutations with regard to wiring and control, thus there is a need to provide a specific example for the operation of the preferred embodiment. For the sake of completeness, FIG. 2 provides a wiring pattern that can be used specifically with FIG. 1B to create an electric motor that uses the present invention as the inner stator mounted on a central hub, with an outer set of permanent magnets likewise arranged as a Halbach array, that can be affixed to an automobile's alloy wheel (not shown) as a rotor.
In the wiring example in FIG. 2, there are three separate wiring phases, A, B, and C and is the same pattern is used for both horizontal and vertical electromagnets as separate sets. Winding is clockwise if the letter is capitalized, and counter clockwise if the letter is in lower case in the diagram. Once this sample electric motor with its alloy rotor wheel is completed, tested and properly mounted, the two pairs of vertical and horizontal stator cores can be physically hardwired and simultaneously commutated by connecting each of the three-phase wires to the appropriate contact points on commercially available single three-phase electric motor controller as shown in FIG. 5. Alternatively, the vertical and horizontal cores can be wired separately but still be electronically interlocked and commutated simultaneously by connecting each phase wire of each core to the appropriate contact points on a dual three-phase electric motor controller, which would be perfect for the dual-sided configuration in FIG. 4. These electric motor controllers can be procured from Kelly Controls ™, Roboteq ™, Azure Dynamics ™, Texas Instruments ™ and other manufacturers.
Once the present invention is connected as shown in the simplified diagram in FIG. 5, force applied to the pedals (not shown) attached to the throttle and regenerative braking potentiometer boxes (labeled as ‘pot’ box in the drawing) would be analogous to stepping on the gas pedal and brake pedal respectively, in a conventional car since this ultimately commands the three-phase electric motor controller to power and commutate the inner stator (that embodies the present invention in this particular example) to drive the rotor's permanent magnets (the outer Halbach array ring).
The diagram in FIG. 5 also shows the converted ‘ignition’ key switch, the subsystems for monitoring, charging and converting power from the batteries, as well as the twelve volt circuitry and controller needed to power auxiliary system in the vehicle such as signal lights, wipers, etc. Most importantly the diagram also shows how contactors, fuses, diodes, current sensors and emergency shutoff switch are applied to ensure safe operation. Again, this simplified diagram contains various items which are not part of the present invention and is thus only provided as an example for completeness.

CONCLUSION, RAMIFICATIONS AND SCOPE

Generally the primary goal of any Halbach array implementation is to maximize efficiency by harnessing the magnified and directed electromagnetic forces produced; otherwise an ordinary, unenhanced electromagnet would be used instead. The stack of coated thin sheets of high-silicon electrical steel that comprise the vertical and horizontal cores have a magnetic resistance that is a thousand times less than empty air. This means that core to core contiguity (measured by the flux aperture 109 shown in FIG. 3A and FIG. 4) maximizes the flow of magnetic flux, whereas relying upon empty air to transmit the magnetic flux between isolated polar cores is massively inefficient (thus counter to the original goal), substantially diminishing or even negating the Halbach array effect.
Moreover, magnetic coils are made of copper, different in composition and intended function to the laminations of high-silicon electrical steel which comprises the core. Thus when the magnetic coils surrounding the vertical core obstructs the path of the magnetic flux produced by the horizontal core (as shown in FIG. 3B) it has no flux aperture 109 needed to enable a strong Halbach array effect. The magnetic flux will follow a path of lesser magnetic resistance, however the magnetic coils are energized wires and its energy is traveling at right angles of the horizontal core's magnetic flux path. Since energized copper is not the same as non-energized, absorbent high-silicon electrical steel of the core, significant dispersion and misdirection of magnetic flux results, which is again massively inefficient, substantially diminishing or even negating the Halbach array effect.
Thus the reader will see that the Halbach array electromagnet with substantially contiguous cores of the present invention provides a fundamental solution a long existing and yet long unresolved need. It is likely the simplest and closest functional equivalent of permanent magnet Halbach arrays as applied to electromagnets.
While the above description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of one preferred embodiment thereof.
Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents.

Claims

I claim:

1. Electromagnetic Halbach array device with substantially contiguous vertical and horizontal cores, comprising:

a) a plurality horizontal and vertical electromagnets arranged in a Halbach array sequence,

b) a plurality of fork-like prongs at the ends of each individual core of every horizontal electromagnet in said Halbach array, and

c) gaps in the magnetic coils that surround each individual core of every vertical electromagnet in said Halbach array, where said fork-like prongs are positioned to provide direct physical contact between cores.

2. Halbach array electromagnetic device with conduits for directly transmitting flux between vertical and horizontal cores, comprising:

3. Method for creating an electromagnetic Halbach array device with substantially contiguous vertical and horizontal cores, comprising:

a) arranging a plurality horizontal and vertical electromagnets in a Halbach array sequence,

b) providing the ends of each individual core of every horizontal electromagnet in said Halbach array with a plurality of fork-like prongs, and

c) creating gaps in the magnetic coils that surround each individual core of every vertical electromagnet in said Halbach array, so that said fork-like prongs can be inserted to provide physical contact between cores.