WO2009021308A1

WO2009021308A1 - Magnetoelectric generator within double coaxial halbach cylinder

Info

Publication number: WO2009021308A1
Application number: PCT/CA2007/001403
Authority: WO
Inventors: Sophie Hofbauer; Satishchandra R. Hassan
Original assignee: Hybrid Strategies Corporation
Priority date: 2007-08-15
Filing date: 2007-08-15
Publication date: 2009-02-19

Abstract

A compact AC magnetoelectric power generator (MEG) is provided to optimize electrical power supply. The outer shell of MEG is composed of polypropylene gas-proof jacket encasing a cylindrical magnetic flux source with a cylindrical axis and a hollow central cavity, (Halbach cylinder). The ends of the cylindrical magnetic flux source are capped by Leupold hemispheres. Inside MEG's permanent magnet shell is a polypropylene structure supporting a ring of permanent magnets, and an air core rotor with external-field Halbach magnetization distribution on a single ring magnet or individual magnets. MEG is cooled with helium at zero degrees C. The motion of the rotor is supplied by external servomotor. The relationship between the rotor, the magnetic flux and individual magnets within the generator ring generates a power output that is exponentially greater than the power supplied to the servomotor providing the rotor motion. 38 claims, 4 Drawing Sheets.

Description

MAGNETOELECTRIC GENERATOR WITHIN DOUBLE COAXIAL HALBACH CYLINDER

TECHNICAL FIELD

This invention relates to permanent magnet devices. More particularly, this invention relates to ironless electric generators designed using the hollow cylindrical flux source (¹HCFS¹) in the form of a cylinder, sphere or hemisphere and their polygonal and polyhedral approximations to said cylinders spheres respectively; and permanent magnets of any type or alloys or rare earth magnets as well as nanomagnets, superconducting magnets or any other type of magnets as yet not identified within ambient or cryogenic environment

BACKGROUND ART

The current demand for electrical power supply that is environmentally friendly and reliable, led to imaginative examination of various resources pertaining to generation of electricity. This invention was inspired by the old Hindu Vedas. An electrical engineer specializing in power generation and a Vedic scholar, Satishchandra R. Hassan from Bangalore India, built a working prototype of an alternator based on the Purusha Sookta, which can be translated as 'formulas for energy generation'.

The present invention we named MEG (MAGNETOELECTRIC

GENERATOR) combines these alternator principles with compact, strong, static magnetic field sources requiring no electrical power supplies, such as permanent magnet structures of unusual form that provide a relatively high uniform magnetic field and flux and have embodied the principles of a Ηalbach Cylinder¹. These configurations are based on the hollow cylindrical flux source (¹HCFS¹), which is a cylindrical permanent magnet shell offering a magnetization vector that is primarily constant in magnitude and produces a field greater than the remanence of the magnetic material from which it is made. The principles of this design are embodied in Klaus Halbach's paper Application of permanent magnets in accelerators and electron storage rings published in Journal of Applied Physics 57(1), 15 April 1985.

Methods for constructing a ¹HCFS sphere' or hollow spherical flux source are disclosed in Leupold, U.S. Pat. No. 4,835,506, entitled Hollow Substantially Hemispherical Permanent Magnet High Field Flux Source. Methods of making the HCFS Cylinder and HCFS sphere are also disclosed in Leupold, U.S. Pat. No. 5,337,472, entitled Method of Making Cylindrical and Spherical Permanent Magnet Structures, and Leupold, U.S. Pat. No. 5,319,339, entitled Tubular Structure Having Transverse Magnetic Field WUh Gradient - all of which are incorporated herein by reference.

Methods of production and magnetization of isotropic and anisotropic permanent magnets, specifically NdFeB, are employed by several suppliers of permanent magnets worldwide and we rely on their expertise in producing the magnets as designed. To understand these matters better, please see the following publications: Design of powder alignment system for anisotropic bonded NdFeB Halbach Cylinders - Zhu, Z.Q.; Xia, Z.P.; Atallah, K.; Jewell, G. W.; Howe, D. Paper presented at Magnetics Conference, 2000 and published in INTERMAG 2000 Digest of Technical Papers. 2000 DEEE International, Date: 4-8 April 2005, Pages: 643 - 643). Also see K. Atallah PCT patent # 6,154,352 Method of magnetizing a cylindrical body and New concept of permanent magnet excitation for electrical machines: analytical and numerical computation - Marinescu, M.; Marinescu, N., Magnetics, IEEE Transactions in Volume 28, Issue 2, Date: Mar 1992, Pages: 1390 - 1393., and The Application of Halbach Cylinders to Brushless AC Servo Motors by K. Atallah and D. Howe IEEE Transactions On Magnetics, Vol. 34, No. 4. July 1998).

The present invention relies on the future replacement of permanent magnets made of rare earth elements with specifically oriented nanomagnets or other suitable materials.

DISCLOSURE OF INVENTION Technical Problem

MEG addresses the global need for the optimization of existing electrical power resources and replacement of expensive to build or polluting sources of power generation and expensive and unreliable power distribution grids with powerful but compact environmentally safe generators that can be placed wherever required and connected in a mesh distribution system that would eliminate the need for lengthy and expensive approvals and construction processes for power generation plants and high voltage transmission lines. An interconnected distribution system also eliminates the need for alternative sources of emergency power. Furthermore, when compared with other power generation sources, MEG is by several magnitudes safer, more convenient, compact, less expensive in terms of capital costs and completely independent of the availability of any of the wind, solar, wave, hydro, hydrocarbons and other presently employed power generation resources.

While there are many patents describing power generation with magnetic structures, none is flexible enough to be employed on a massive scale in terms of continuous viable output, manufacturing, safety, compactness, sturdiness, and 'plug- in' maintenance simplicity. The limiting factor that exists today for this invention is the availability of the rare earth magnetic material which, being a commodity, is increasing in price as the demand is increasing. Therefore all efforts are made by the inventors of MEG to replace these magnets with specifically oriented nanomagnets of equal or better magnetic properties, while preserving the manufacturing and operational simplicity of the invention. However, even with a tripling of the price for rare earth magnetic materials, the total installed and operating cost per MWhr (1 ,000,000 KW/hr) will remain below any other form of power generation.

Technical Solution

We are interested in the amplification and disturbance of the magnetic flux created by the influence of the magnetic elements in MEG's magnetic shell and inner magnetic ring ('generator ring'), thus causing the EMF to flow into the generator ring magnetic elements which also act as conductors. This is accomplished with the movement of air core rotor with the Halbach magnetization distribution (Fig. 1) which at the same time 'writes' the sine wave on the generator ring which creates multiple phases if such are desired, or with the output of multiple magnets contributing to each phase in case of 3 phase design.

Although we are showing here the Halbach Cylinder capped with a parametric

Leupold cap, similar results can be obtained with Leupold geometric cap or without the end caps, using only the Halbach Cylinder of length approximating the outside diameter added to both ends of the portion used for the generator ring. Because the magnetic field drops off towards the ends of the ring, the ring can also contain some of the elements not possible to insert in the capped configuration shown in Fig.6. This is much simpler and less expensive solution for smaller applications. However, several design considerations must be examined before the correct choice is made. The techniques for enclosing the MEG's internal ring of magnetic elements (which, in combination with the rotor, is the actual generator) with Halbach Cylinder and Leupold's top and bottom hemispheres are employed in MEG with specific purposes, namely:

1. Safety - where it is important to minimize the influence of magnetic fields on the surrounding environment that may be affected by them, such as in the hospital, laboratories, computer rooms or airplanes. The Halbach Cylinder concept and its polygonal approximations have been particularly useful as a common permanent magnet configuration to confine transverse magnetic fields to cylindrical magnets and near cancellation of the magnetic field outside the structure, making this device safe for all other devices prone to magnetic disturbances. This is also true for the straight ring version, but to a slightly lesser extent due to the unprotected ends. For example, see H. A. Leupold and E. Potenziani, An Overview of Permanent

Magnet Design U.S. Army T.R. SLCET-TR-90-6, August 60 1990.

2. Magnification of magnetic field, and therefore flux, to increase efficiency of the generator. The magnetic field and flux created by the above structure will pass through the internal magnetic elements of the internal ring and the rotor described further herein, up to some magnitude greater than the remanence of these magnetic elements without affecting their magnetic orientation, thus contributing to the vector sum of the internal field of the Halbach Cylinder and the field sustained by the internal magnetic elements (also noted by Herbert Leupold in patent US 5,349,258). However, care should be taken that the contribution of internal magnets to the internal magnetic field is not greater than the shielding effect of the magnets in Halbach Cylinder. Otherwise an additional magnetic shield around the device is required.

3. Equalization of the magnetic field and therefore flux throughout the MEG to correct the inherent weakness of the Halbach Cylinder mat the magnetic field begins to drop near the ends of the ring until the field is only about a half as strong as the field at the centre of the cavity's cylindrical axis. This has been addressed by Herbert Leupold's patent US 6,856,224 End Caps on Hollow Magnets. In order to control the magnetic field dropping off near the ends of the ring, a half of Leupold's HCFS sphere

(Fig.3 and 4) is utilized at both ends of the ring. Each half contributes the missing part of the transverse magnetic field in the ring, thus equalizing the field throughout the length of the ring and into the half spheres. The Halbach

Cylinder with the caps enclosing both ends and having the same cavity diameter and shell axis produce a transverse, undistorted, biasing magnetic field and achieves uniform magnetic flux source within the structure's hollow cavity.

This is important where the diameter of the Halbach Cylinder is large and therefore the extensions to the length would add considerable bulk.

Design parameters

It is a primary objective of this invention to create an electrical generator by locating within the Halbach Cylinder that contributes and contains the magnetic flux, another ring of anisotropic or isotropic bonded NdFeB permanent dipole magnets that act as contributors of magnetic flux, as windings and as conductors; and inserting in the circle formed by said magnets an air core rotor with a single ring isotropic bonded NdFeB magnet with external field Halbach magnetization distribution (Fig.l). Although other magnetic materials can be used, for the optimal ratio of the size, price and efficiency of MEG, we are considering the magnetic material with the highest Maximum Energy Product (BH)^ and compensating for its low operating temperatures with cooling the MEG interior.

The relationship between the rotor and each internal ring magnetic element creates EMF that is the product of the total disturbed magnetic flux by the rotor at the air gap. Similar relationships have been also noted by others, most notably, in H. Leupold's patent US 5^49,258 and R.F. Post's patent US 6,906,466 B2.

At this point is important to note that only the relative motion between the combined magnetic field of MEG shell and the rotor with Halbach array is required. Since the only mechanical energy is supplied by the rotor connected to a small servomotor located on the outside of the capped Halbach Cylinder assembly, it is interesting to note that the total output of the whole generator is the sum of the output from the individual internal ring magnetic elements which act as individual generators and also as conductors. In other words, as a complete device, MEG exhibits overunity - an apparently much greater energy output then input. However, this overunity is illusionary, because, as we said, the relationship is between the rotor and the individual magnet, and at this level the laws of energy conservation are respected. We simply add the individual outputs to describe the total energy generated from the MEG.

In the following equations we rely on the knowledge inherent in the previous art incorporated herein by reference to a patent or a publication or, if such reference was previously made, to the name of the author, which allows us to shortcut the lengthy evolution of equations and associated logic, and adapt the equations where applicable to this invention.

The total magnetic induction in air gap between the MEG's generator ring and the rotor is composed of three sources of magnetic flux

where Bn_c is the induction of the Halbach Cylinder, Bg is the air gap flux of the generator ring, and Br_g (0) is the air gap flux of the rotor at a given rotor magnet magnetization angle.

Since the half spheres on the Halbach Cylinder are equalizing the magnetic field in the Halbach Cylinder, it follows that their magnetic field is the same as in the Halbach Cylinder and we can ignore their contribution for the purpose of equation [2]. The dipole magnetic induction inside the Halbach Cylinder of infinite length is given by the expression derived by Klaus Halbach, which in our example as per FIG. 5, we can express as

where CN value for 8 magnets is 0.90 and for 16 magnets is 0.96.

In the publication Trapped-flux internal-dipole superconducting motor/generator Hull, J.R.; SenGupta, S.; Gaines, J.R. Applied Superconductivity, IEEE Transactions on Volume 9, Issue 2, Jun 1999 Page(s):1229 - 1232 the authors stipulate the optimal value for Ri /R₀) is in the range of 0.7 to 0.75 for the motor- generator application, although this observation applies to a rotating shell.

The flux density for the air gap between the rotor and the generator ring, without the influence of the flux generated by the Halbach Cylinder is given by the sum of the flux created by the generator ring magnets (which for all intents and purposes is the same as the coils and armature in the field winding type of generator) plus the rotor with Halbach magnetization distribution.

According to K. Atallah and D.Howe in The Application of Halbach Cylinders to Brushless AC Servo Motors, the flux density of any point on the rotor with Halbach magnetization distribution is expressed as

Brg(θ)=Bmsin(NΘ)=^^\l-(Rr/Rr_of^ [3]

where B_m is the peak airgap flux density delivered only by the rotor magnets, B_r is the remanence, Rg_1n is the generator ring inner radius, Rr i and Rr₀ are the inner and outer radii of the rotor magnets, θ is the angle of magnetization of the individual segment of the rotor magnetic element (Preferably this is a single isotropic bonded ring with Halbach magnetization distribution equal to the number of magnetic elements required in a wavelength (suggested 4), multiplied by the number of poles). For an air cored rotor K=I and for simplicity, we neglect the slotting effects and assume the relative recoil permeability of the permanent magnet to be 1.0 (substitute real values in the design).

The number of poles in the rotor and the number of magnets in the generator ring must match (M_g=P). Such design will produce a continuous torque in the same direction (see PCT patent WO 00/46906), thereby lessening the demand on the servomotor. The number of poles denotes the number of wavelengths around the rotor's surface as per equation [3]. Their azimuthal length X₀ relative to the Ri of the generator ring is

where M_g* is the width of the generator magnet perpendicular to lines of flux. M_gι s the width of the air gap between the magnets and l_g is the length of the air gap perpendicular to the lines of flux between the rotor and generator ring. The width of the individual segment of magnetization is % of λ_o. The optimum thickness for Halbach array on the rotor corresponds to that thickness which maximizes the ratio of the generating capacity to the mass of Halbach array. The generating capacity is proportional to [Br_g (θ)] which in turn is a function of the thickness of the Halbach array- see equation [6]. According to R.F. Post the optimum magnet thickness for p»l turns out to be 0.2Q/L

The air gap flux density in the generator ring can be established with this equation:

s

where [6]

Electromagnetic torque

Although here the MEG's Halbach array rotor torque is the servomotor's load, in order to select the proper servomotor we need to assure that it is capable of providing the necessary torque. The electromagnetic torque of a surface mounted magnet rotor is given by K. Atallah and D. Howe as:

Tac = ≡LkvBmRginHaQrms [7]

Rgin is the radius of the generator ring l_a is the active length, β_/m_s is the rms electric loading and A*, is the winding factor which we can assume here as 1.0. The weight of the rotor magnet ring must be added to the load of the servomotor.

Magnet size in generator ring

The physical size of MEG is directly related to the required magnet volume. Since we mentioned earlier that due to permanent magnet "transparency" care should be taken not to exceed the magnetic field and flux of the external shell of MEG with the contribution of internal magnets, the good combination of contributions should be 50% for the shell, 45% for the generator ring and 5% for the rotor. The size of the particular magnets can be determined from the manufacturer's specifications which usually carry the equations needed.

Calculation of power output and physical size of MEG

To obtain the optimal combination of power output and size for MEG and therefore use it for scaling for different applications, we need to analyze these values relative to the design parameters outlined above. We know what output power and voltage we need to obtain. The constraint therefore is the frequency which dictates the voltage. The total power output of MEG is the sum of the power delivered by each of its magnets in the generator ring.

Owing to the convergence of three flux sources with one of them rotating with wave distribution which in itself is complex, the actual magnetic flux distribution at a particular location in the air gap and calculation thereof is fairly complicated and best done with a computer model. However, the design with multiple magnets, four of which contribute to each phase (in 3 phase design), averages the different pulses of energy through each magnet, so for general calculation purposes we can ignore the localized differences.

Voltage

This is the most important variant dictating the size of MEG. In a single generator magnet, voltage is derived from the time varying azimuthal flux through the air gap produced by the azimuthal component of the magnetic fields of the

Halbach array on the rotor. Integrating this field over the area enclosed by the magnet results in an expression for the induced voltage as a function of time:

V, = BRr_ohω, [8]

where Rr₀ is the outer radius of the rotor, h is the height of the generator magnet lying in a radial plane, (O₀ is the angular velocity of rotor in radians, Rgι_H and Rg_ou_t being the inner and outer radius of ring magnet respectively and measured at the axis, and / being time in seconds. Then the output power of each phase into a resistive load with resistance R_L , inductance L_Ot and magnet resistance R₀ is given by the equation:

- watts/magnet [9]

where the inducta

nce (self plus mutual) Lo = [ 10] lkdc

with /*c(m) is the distance around the perimeter of one of the generator magnets measured in the direction of magnetization, k=27l/X (azimuthal wavelength of Halbach array on the rotor), μ_o is the permeability of free space=4πxl(T (henrys/meter), and d_c (m) is the center to center spacing of generator magnets. In practice, resistance R₀ of the magnet «RL can be neglected in comparison with other quantities. In this case the maximum power that can be delivered occurs for a load resistance equal to the inductive impedance of generator magnets (oL_o and is given by the equation

The efficiency is given by the expression

The absence of iron in the magnetic circuit means that only simple air core inductances and winding (magnet) resistances must be taken into account to calculate these quantities because there is no conventional core loss or eddy current loss.

Once we have all the components of MEG evaluated, we can refine the design. At this point we refer to an orthogonal per phase impedance model presented by Ozdemir GoI and Bijan Sobhi-Najafabadi in the their paper Use of Impedance

Models in Permanent Magnet Synchronous Generator Design published in

Electrical Machines and systems, 2003. ICEMS 2003. Sixth International Conference

Date: 9-11 Nov. 2003, Pages: 112 - 115 vol.1. The equations presented there should be considered in conjunction with the equations suggested here, as they allow for more accurate modeling of steady state performance of MEG regardless whether it is operating in synchronous mode or through frequency transformer (i.e.: from 400 Hz to 60 or 50 Hz). Other design considerations

For 400Mz frequency operation, the rotor magnet and its holding rings must be designed with high strength composite material such as carbon fibers bonded with epoxy resins.

It is important to keep NdFeB magnets reasonably cool to prevent demagnetization, especially that MEG is an enclosed space. A space of minimum 2 cm wide is needed between the outer shell and the generator ring magnets for the circulation of cooling gas and for the polypropylene structure (Fig.6) that will support all the elements of MEG. MEG interior should be kept at 0 degrees Celsius, although a small variation of this temperature does not make much difference. This requires cooling with an inert gas (in our example, helium) which also preserves the magnets which are prone to oxidation. The cooling coil can be inserted into the polypropylene duct loop connecting MEG's both ends close to one end and inline fan can be inserted close to the other end. The refrigerant piping, power and control wiring from MEG wiring will exit through the gastight sealed tee in the cooling duct.

The entire MEG device, including the duct is wrapped in sheet insulation and sealed with foam insulation in a cold section of the enclosure containing MEG. The refrigerant compressor, small helium tank to top off any lost helium, battery, other power conditioning devices and power and control panels are located in the ambient sections of the enclosure containing the MEG. MEG will be remotely monitored by a proprietary autonomous monitoring system via wired and wireless communications.

Advantageous Effects

MEG can be installed anywhere in new installations or where additional power is needed in existing power distribution systems. Its starting power to the servomotor can be supplied from the battery or from external source. Furthermore, the redundant power can be sold to the utilities or to neighboring customers interconnected so everyone has at least three suppliers via different routes thus eliminating the need for emergency generators. There is no need for large generation stations and high voltage distribution system. We suggest the largest MEG size to be 300kWhr, which requires an enclosure approximately 1.5mxl.5mx2m in volume for all factory assembled

MEG components including power and control panels and allows for easy plug-in installation. Power conditioning equipment is separate.

Description of Drawings

FIG. 1 depicts Halbach magnetic excitation concept on a rotor; FIG. 2 depicts ideal and actual Halbach Cylinder structure;

FIG. 3 depicts parametric capped Halbach Cylinder FIG. 4 depicts geometric capped Halbach Cylinder

FIG. 5 illustrates the Magneto-Electric Generator (MEG) in present invention; FIG. 6 is a cross-section of the Fig.5 for greater clarity of illustration; FIG. 7 shows the power and control schematic.

Note: Other than indicated, all descriptions refer to Fig 6.

A Halbach ring / is magnetized as shown ii,with top and bottom Leupold half spheres 2, create an enclosed space with a uniform transverse magnetic field 16. Within this space is inserted a polypropylene structure on friction-fit support 13. The internal polypropylene structure has a neck 20 protruding through the top and bottom of the Leupold half spheres and terminating in the flange 21 joining the outer gas-proof casing 7 over the generator.

The generator ring of cubic magnetic elements 6 with alternating polarity is inserted into the polypropylene structure 13, with each magnetic element 6 separated by a 3 mm air gap 29 (Fig. 5) at the interior ring circle widening toward the back of the magnetic element to allow for maximum coolant circulation. The air gap is filled with a trapezoid pouch containing castor oil or other dielectric fluid enclosed in a thin, flexible, oil resistant material. The pouch should be 3mm wide at the air gap x 50mm long x width of the space between the magnets. The pouch is friction fitted between the magnets and extends over the entire length of the magnetic element

Each magnetic element 6 serves as a source of magnetomotive force which sustains the magnetic fields that extend to and from its poles or pole faces. At the back of each magnetic element a copper conductor 5 gathers the electric charge.

An air core rotor 10 with a single ring 9 with isotropic Halbach magnetization and four magnets per pole, or with anisotropic individual magnets with said magnetization is separated from the generator ring with an air gap 8. The rotor is controlled with a servo-motor 39 (Fig.7) located outside of the structure. The shaft 19 of the servo-motor terminates inside the rotor with a polypropylene screw cap 11 and is controlled by a magnetic bearing 14.

The generator has a circulation space 3 around and at the top and bottom of generator ring of magnetic elements 6, for cooling with helium circulated by an inline fan 26 (Fig.7) inserted within a sealed polypropylene duct to prevent thermal destruction of permanent magnets. The generator and all the components within the cold section are wrapped in an insulation blanket and then the cold section is filled with foam insulation. A refrigerant piping leads from the helium cooling coil inserted in the helium circulating duct into the ambient section where the adequately sized cooling compressor 30 (Fig.7) is located. The same compressor also cools the ambient section with fan 24 (Fig.7) and a coil controlled by a temperature sensor.

The air gap, torque, helium pressure and temperature sensors 18a to 18c control the helium fan 26 (Fig.7) and the cooling coil, as well as the magnetic bearing 14 and the servo-motor 39 (Fig.7) which is the primary mover for the rotor, and also regulates the frequency and power output of the generator. Low voltage power panel 44 (Fig.7) - 120/208 V 30 4 W at 60Hz or any other international configuration, and control panel 43 (Fig.7) supply the power and controls inside MEG. A helium tank located in the ambient temperature section makes up for any lost helium via the check valve and solenoid 38 (Fig.7).

The wiring 5 from individual magnetic elements of the generator ring are extending through the neck 20 of the generator's casing 7 into the helium duct and through the cold section into the ambient section and high voltage power control panel 28 (Fig.7). The panel is vented with a fan 45 (Fig.7) controlled by the temperature sensor. Individual relay control 40 (Fig.7) on each conductor prevents the power rebound back into the generator.

Note: The following descriptions refer to Fig.7. The conductors are joined per phase as indicated 12, into a 3 phase supply further protected by a 3 pole breaker 41. MEG is connected to an outside disconnect switch 42 and to a distribution system 52 (or alternatively, to voltage/power conditioner as required). A 3 phase supply 45 is taken of the mains and protected with the breaker 49 through an internal transformer 50 to feed the motors and other equipment through power panel 44 within MEG. A stand-by rechargeable battery 54 and inverter 55 are used to start the servo-motor 39 initially and in case of MEG shut-down by the remote control system. The control panel 43 communicates wirelessly and through wired connection with a remote control server. MEG is monitored and controlled by the proprietary autonomous Hybrid Intelligent System.

It is to be noted that the results of this invention may also be accomplished through the use of polygonal and polyhedral approximations to the Halbach Cylinders and HCFS spheres respectively; straight section of Halbach Cylinder without caps; and permanent magnets of any type or alloys or rare earth magnets as well as nanomagnets, superconducting magnets or any other type of magnets as yet not identified, within ambient or cryogenic environment.

It is to be further understood that other features and modifications to the foregoing detailed description are within the contemplation of the present invention, which is not limited by this detailed description. Those skilled in the art will readily appreciate that any number of configurations of the present invention and numerous modifications and combinations of materials, components, geometries, arrangements and dimensions can achieve the results described herein, without departing from the spirit and scope of the invention. Accordingly, the present invention should not be limited by the foregoing description, but also by the appended claims.

Claims

1. A compact, alternating current generating device containing: a) A MAGNETOELECTRIC GENERATOR (MEG) comprising of an outer polypropylene jacket encasing a shell composed of Halbach ring of magnetic elements and Leupold geometric or parametric top and bottom caps of magnetic elements which generate transverse magnetic field to assist in producing uniform, biased magnetic field perpendicular to cylindrical axis, confined within the hollow central cavity of the device; b) A cooling system for the said generator; c) A control and power sections for the said generator.

2. For smaller MEG units the outer shell of the generator in claim 1 may also be constructed with Halbach ring only and without Leupold caps, with all the other items mentioned below still applicable. Such device may need an additional magnetic shield, which does not change the purpose and spirit of MEG.

3. Within the generator of claim Ia), there is an internal precision-made polypropylene structure to hold generator magnets, rotor, wiring and other assistive devices that are friction fitted into the polypropylene structure.

4. The polypropylene structure of claim 3 is of open form allowing for free circulation of cold helium or another inert gas, and forms two necks terminating in flanges protruding from the top and bottom of the outer shell. The necks seamlessly join the outer gas-proof polypropylene jacket over the outer magnetic shell. Said top and bottom necks channel the electrical conductors and helium cooling to and from the interior of the device in claim Ia.

5. The polypropylene structure described in claims 3 and 4 supports from inside the dipole (or any multiplication thereof) Halbach cylinder made of minimum 8 trapezoid anisotropic or isotropic bonded NdFeB dipole permanent magnets with Halbach magnetization pattern. The Halbach cylinder is capped by Leupold end caps with matching number of magnets and magnetization pattern; Leupold end caps being a hemispheric section of a Leupold magic sphere, and having a cavity diameter and shell axis equivalent to the Halbach cylinder. The Halbach cylinder achieves a highly effective and uniform magnetic field within a Halbach cylinder and on an axis of the Halbach cylinder's end, because the magic hemispheric caps produce a transverse, undistorted, biasing magnetic field.

6. The polypropylene structure in claims 3 and 4 may be made of other non- conductive materials that have similar or better properties similar in purpose to this invention, such as carbon fibers bonded with epoxy resins.

7. The magnetic elements used in construction of the outer shell in claim 1 may be permanent magnets, nanomagnets superconducting magnets, or any other type of magnets available or not yet available that can be magnetized or have inherent magnetization suitable for application similar in purpose to this invention.

8. The polypropylene structure described in claims 3 and 4 also supports cube shaped anisotropic or isotropic bonded NdFeB dipole permanent magnetic elements arranged with alternating polarity in an internal generator ring around an air core rotor.

9. The adjacent magnetic elements in claim 8 are separated from each other by an air gap, which should not be larger than 3 mm at the inner diameter of the generator ring. The air gap is filled with a pouch containing castor oil or other dielectric fluid enclosed in a thin, flexible oil resistant material. The pouch extends over the entire height of the magnetic element and about 2 cm in the magnet length.

10. The pole faces of each magnetic element in claim 8 are aligned along the cylindrical radius of the said generator ring.

11. The magnetic elements used in construction of the internal generator ring in claim 8 may be permanent magnets, nanomagnets, or any other type of magnets available or not yet available that can be magnetized or have inherent magnetization suitable for application similar in purpose to this invention.

12. Each magnetic element in claim 8 serves as a source of magnetomotive force which sustains the magnetic fields that extend to and from its poles or pole faces.

13. The magnetic elements of the generator ring in claim 8 also magnify the magnetic field and flux created by the MEG permanent magnet shell described in claim 5.

14. A bare copper bar is attached to the back of each magnet in the generator ring in claim 8 to collect the electrical charges from the ring magnet An insulated copper wire sized accordingly to the carried current from the magnet is attached to the bar to carry the electrical charge outside MEG in claim Ia. The copper bar and wiring can be replaced with any other type of conducting material similar in purpose.

15. Inside the generator ring in claim 8 is an air core rotor made of a plurality of anisotropic magnets or single isotropic bonded NdFeB magnetized ring with external-field Halbach magnetization distribution arranged in number of poles matching the number of magnets in generator ring, in alternating North and South orientation and each pole having four magnetization directions. The rotor is separated from the generator ring magnets with an air gap with width directly proportional to power output.

16. The magnetic elements used in construction of the rotor in claim 15 may be permanent magnets, nanomagnets magnets or any other type of magnets available or not yet available that can be magnetized or have inherent magnetization suitable for application similar in purpose to this invention.

17. The rotor in claim 15 is friction fitted into the polypropylene rotor holding form being part of the structure described in claim 3 and 4.

18. The rotor in claim 15 is mechanically powered by an external servo-motor which acts as a primary mover, voltage, frequency and torque regulator. The primary mover can be also any other type of rotation source such as wind, solar, wave, hydro, fossil fuel, and secondary functions of engines or motors suitable for application similar in purpose to this invention whether coupled directly or through motion conditioning devices.

19. The shaft of the rotor in claim 15 is held by a magnetic bearing which also keeps the air gap constant between the rotor and the generator magnets via sensor located at the top and bottom edge of the air gap.

20. The rotor in claim 15 disrupts the magnetic flux in claim 13 pushing the electric charges into the internal ring dipole magnetic elements in claim 8 which also act as electrical conductors in claim 14.

21. The rotor's external-field Halbach magnetization distribution on individual anisotropic or isotropic bonded NdFeB magnetized ring magnet in claim 15, "writes" the sine wave on the generator ring in claim 8, allowing the pickup of multiple phases or 3 phases with plurality of magnets contributing to each phase.

22. In particular, the rotor's sinusoidal air gap field distribution in claim 21 maintains the low cogging torque and therefore minimizes the speed ripple and achieves a high positional accuracy. In addition to its torque capability, the induced EMF waveform has a very low harmonic content

23. It is the relative motion between the rotor in claim 15 and the magnified magnetic field in claims 5, 13 and 20 that generates EMF that is proportional to the total flux in claims 5,13and 20.

24. The charge from the EMF in claim 23 is pushed through each generator ring magnetic element in claim 8. The total output from all magnets produces multiple magnification of supplied power to the servo-motor in claim 18 which controls the motion of the rotor in claim 15.

25. Although the servo-motor in claim 18 controls the mechanical motion of the rotor in claim 15, the power output from the generator ring in claim 8 is not related to the power supplied to the said servo-motor, but directly related to the EMF of the sum of flux in claims 5,13 and 20 and mechanical motion of the rotor in claim 15 that disturbs it.

26. The said rotor's mechanical motion is assisted by the attraction and repulsion inherent in the alternating polarity of the magnets in generator ring in claim 8 and the alternating polarity of the rotor's poles in claim 15.

27. Furthermore, the relationship is between the said rotor, the said magnetic flux in claims 5, 13 and 20 and each individual magnetic element in the generator ring in claim 8. Each individual magnet is actually an individual generator. Therefore the laws of energy conservation are preserved at the individual rotor- generator magnet relationship which gives an output relative to the size and efficiency of the magnet and the MMF of magnetic flux in claims 5,13 and 20. Consequently, the power output of the MEG in claim Ia) is the sum of power output from all the magnets in the internal ring in claim 8.

28. The entire MEG structure in claim Ia) is cooled with low pressure helium in claim Ib) or another inert gas to prevent magnet destruction due to increase of operating temperature and oxidation of magnets.

29. The cooling in claim Ib) is delivered via sealed gas-tight polypropylene duct connected to the said MEG via the necks of its polypropylene casing in claim 4. The in-line squirrel cage circulating fan is located on the return path (warm side) from the MEG. The cooling coil is located inside the duct near the entry (cold side) to the MEG. The cooling coil is a standard freezer coil, with hydrocarbon or equal high efficiency refrigerant and compressor sized to keep the inside of the said MEG at zero degrees Celsius or lower. A cryogenic type of cooling device may also be used as per magnet specifications. The warm side of the cooling coil is vented in the ambient section of MEG where the compressor is located.

30. The MEG in claim Ia) and helium circulation system in claim Ib) are wrapped in a sheet insulation and encased in a cold compartment of the MEG enclosure which is then completely filled with foam insulation.

31. The controls and items not needing cooling in claim Ic) are encased in the ambient temperature compartment of the MEG enclosure.

32. The MEG in claim 1 is encased and sealed for safety in a locked metal enclosure with adequate venting of ambient sections, and equipped with monitoring and alarm systems remotely monitored and controlled by a proprietary autonomous monitoring system which monitor and control each element of MEG.

33. The said MEG is connected into the power distribution system directly or through a power conditioning transformer.

34. In addition to being continuously monitored for performance, MEG in claim 1 is inherently designed to safely stop when any element fails because the rise in temperature above the operating temperature of rare earth magnets destroys the magnetization, causing MEG to cease working. The rechargeable battery located in the cartridge is designed to power only the control panel which automatically breaks the connection with the external power source to the servomotor.

35. MEG can produce single or multiphase power of any frequency or voltage. Theoretically, indefinite number of magnets and indefinite size MEG is possible. However, considering the cost/benefit ratio and suitability of MEG for distributed system, for most applications 1 MW units are the maximum practical size, with 25 KW being the minimum.

36. A number of such cartridges can be grouped together or distributed close to the electrical load, thus eliminating the need for higher voltages than the load requires.

37. The cartridge allows for distributed power supply in a mesh distribution system that eliminates large power distribution lines, and assures uninterrupted power without a need for emergency generators. Within the mesh distribution system, a cartridge can be taken out of the system without noticeable impact on the power supply.

38. A proposed mesh distribution system consists of several interconnected power cartridges where each power cartridge is connected to at least three others. This assures a better load balance and redundancy. The mesh distribution system is suitable for localized or municipal applications.