MXPA06002382A - Selective alignment of stators in axial airgap electric devices comprising low-loss materials - Google Patents

Abstract

An axial gap dynamoelecic machine comprises first and second stators (42/44) disposed coaxially with an intermediate rotor (40). The stators (42/44) are selectively aligned with an axial offset between the positions of their respective teeth and slots. The stators comprise toroidal cores having laminated layers composed of a material selected from the group consisting of amorphous and nanocrystalline metals and optimized Fe-bmsed alloy. Optionally, the machine further comprises misalignment means (46/48) for adjusting the offset of the stators. Adaptive adjustment permits the machine to be operated to in a mode that reduces the back EMF of the motor, allowing constant voltage to be maintained as speed is increased. Reducing back EMF also allows a wider range of operating speed, especially in combination with use of high pole counts. Alternatively, the machine can be operated, e.g. at lower speed, in a constant torque mode.

Description

For two-letter codes and other abbreviations, referto the "Guidance Notes on Codes and Abbreviations" appearing at the beginning of the regular issue of the PCT Gazette.

SELECTIVE ALIGNMENT OF STATORS IN ELECTRICAL DEVICES OF AXIAL ENTREHIERRO COMPRISING LOW LOST MATERIALS FIELD OF THE INVENTION The invention relates to a dynamo-electric, rotating machine; and more particularly, to an axial air gap machine comprising two or more stators, wherein the EMF generated in the machine is controlled through the selective rotational alignment of one or more stators in relation to a reference 1 of the stators. BACKGROUND OF THE INVENTION The electric motor and generator industry is continually looking for ways to provide dynamo-electric rotating machines with increased efficiencies and increased energy densities. As used herein, the term "engine" refers to all classes of motor and generating machines that convert electrical energy to rotational movement and vice versa. Such machines include devices that can alternatively be called motors, generators and regenerative motors. The term "regenerative motor" is used herein to refer to a device that can be operated either as an electric motor or as a generator.

Ref.:170676 A wide variety of motors are known, including the types of permanent magnet, coil field, induction, variable reluctance, switched reluctance, and brush type and brushless. These can be energized directly from a direct or alternating current source provided by the utility grid, batteries or other alternative sources. Alternatively, these can be supplied by current having the required waveform that is synthesized using the electronic drive circuitry. The rotational energy derived from any mechanical source can drive a generator. The output of the generator can be connected directly to a load or conditioned using the set of electronic energy circuits. Optionally, a given machine is connected to a mechanical source that functions either as a source or mechanical energy dissipator during different periods in its operation. The machine can thus act as a regenerative motor, for example, by connecting through the set of power conditioning circuits capable of performing the operation in four quadrants. Rotating machines ordinarily include a stationary component known as a stator and rotating component known as a rotor. The adjacent faces of the rotor and stator are separated by a small air gap traversed by the magnetic flux that connects the rotor and the stator. It will be understood by those skilled in the art that a rotating machine may comprise multiple mechanically connected rotors and multiple stators. Virtually all rotating machines are conventionally classifiable either as radial or axial air-gap types. A type of radial gap is one in which the stator rotor is radially separated and the through-flow is directed predominantly perpendicular to the axis of rotation of the rotor. In an axial air gap device, the rotor and stator are axially separated, and the flow crossing is predominantly parallel to the rotational axis. Except for certain specialized types, motors and generators generally employ soft magnetic materials of one or more types. By "soft magnetic material" is meant one that is easily and efficiently magnetized and demagnetized. The energy that is inevitably dissipated in a magnetic material during each magnetization cycle is called hysteresis loss or core loss. The magnitude and loss of hysteresis is a function of the amplitude and frequency of excitation. A soft magnetic material also shows high permeability and low magnetic coercivity. Motors and generators also include a magnetomotive force source, which can be provided either by one or more permanent magnets or by an additional soft magnetic material, surrounded and circularly by windings carrying current. By "permanent magnet material" also called "hard magnetic material" is meant a magnetic material that has a high magnetic coercivity and strongly retains its magnetization and resists being demagnetized. Depending on the type of motor, the permanent and soft magnetic materials can be placed on either the rotor or the stator. Until now, the preponderance of currently produced engines uses as a soft magnetic material various grades of electric or motor steels, which are iron alloys with one or more alloying elements, including especially silicon, phosphorus, carbon and aluminum. More commonly silicon is an element of "dominant alloy. While it is generally believed that motors and generators having rotors constructed with material advanced permanent magnet and stators having cores made with soft materials of low loss, advanced, such as amorphous metal, they have the potential to provide efficiencies and densities substantially higher energy compared to engines and conventional generators radial gap, there has been little success in building such machines of either the radial gap type or axial gap. Various attempts to incorporate the amorphous material into conventional machines radial or axial airgap have largely been commercially unsuccessful. early designs mainly involved substituting the stator and / or rotor with coils or circular laminations of amorphous metal, typically cut with teeth through of the internal or external surface. Amorphous metal has unique magnetic and mechanical properties that make it difficult or impossible to directly replace ordinary steels in conventionally designed engines. Many applications in the industry - electric motors and generators require a machine capable of operating significantly beyond a certain rotational base speed during at least part of its ordinary use. The base speed is the highest value achievable when an electrical device is operated in a constant torque mode. Above the base velocity, the posterior electromotive force ordinarily exceeds a nominal supply voltage. However, design optimization is challenging many applications in which the machine must operate at a wide range of speeds. The problem is especially acute for systems that do not incorporate a proportional or variable speed gearbox or other speed adjustment device. For example, low-speed operation in an electric vehicle often requires constant torque operation to move heavy loads or traverse rough or steep terrain, such as mountain roads that are normally performed at much less than a base speed. However, high-speed operation, for example, to cross level roads or industrially developed sites, may require double or triple the base speed. For high-speed operation, the torque requirements are generally low, and operation at constant power, where the available torque is inversely proportional to the speed, could provide significant advantages. A recognized disadvantage of typical permanent magnet machines is that the electromotive force (EMF) generated from the machine is a direct linear function of the rotational speed of the machine. The EMF generated is also directly proportional to the energy output for a given current. Although greater potential can be obtained at higher speeds, higher voltages are concomitantly produced during generation applications. Similarly, in motor applications, the power supply voltage must be increased to go above the voltage requirement at the base speed. In any case, construction techniques and materials, particularly including insulation and semiconductor and electronic elements in the control circuitry, must be selected accordingly. As a result, higher voltages are difficult and not that impossible to control at low cost. In this way, a controlled or controllable generated EMF is a desirable feature in a machine, since speed limitations can be relaxed. The references of the prior art have firm methods of maintaining a constant terminal voltage during the operation of electrical devices, based on the manipulation of the air gap between the rotor and the stator. A small decrease in the air gap results in an increase in the voltage (EMF) generated in the stator windings, and vice versa. U.S. Patent Nos. 2,892,144 and 2,824,275 describe a generator comprising a simple stator placed opposite a rotor, wherein the stator is mounted such that an increase in the torque during the operation ultimately causes the movement of the stator. towards the rotor, for example, tending to reduce the air gap. An increased load (torque) that could ordinarily result in a drop in output voltage also causes a reduction in the air gap, which results in an increase in voltage.

In an alternative embodiment, U.S. Patent No. 2,824,275 discloses a generator comprising a fixed stator positioned opposite a rotor, wherein the rotor is mounted such that an increase in speed during the operation ultimately causes the movement of the rotor. rotor away from the stator, for example, tending to increase the air gap. Since the output voltage is proportional to the speed, the increase in speed could result in the increase in voltage. However, an increase in the air gap acts to reduce the voltage. As yet another example of an air gap manipulation of a different type of electrical device, U.S. Patent No. 5,627,419 discloses a modified radial air gap flywheel with auto-coupling means to automatically decrease the adjustable air gap between the stator and the steering wheel in response to the electromagnetic torques exerted on the stator during the moment of rotation or decrease in rotation, as well as to increase the adjustable air gap during freewheeling operation. Other methods are known to control the output parameters of the electrical devices during operation by manipulating the overlap between the rotor and the stator in the radial air gap machines.

As a method of maintaining constant speed during operation, U.S. Patent No. 403,017 describes the use of centrifugal force on the governors coupled to the rotor of a radial air gap motor, to reduce the axial overlap between the rotor and the rotor. the stator. A reduction of the load on the motor would normally result in an increase in speed, but the increase in speed increases the centrifugal force on the governors, which causes an axial exploitation of the rotor relative to the stator, thereby reducing the overlap between the rotor and the stator. The reduced overlap between the rotor and the stator results in a reduced torque, which then counterattacks the tendency for the speed increase. More recently, the United States patent No. 6,555,941 discloses a method for reducing the posterior EMF of a radial air gap motor, by axially displacing the rotor relative to the stator, thereby reducing overlap. As the rotor is displaced in greater axial misalignment with the stator, the flow of the magnet over the stator field coils is reduced, thereby reducing the subsequent EMF which limits the speed. With the rotor aligned, the motor operates in the constant energy mode, where the available torque is inversely proportional to the speed.

U.S. Patent No. 6,194,802 also discloses a method for reducing subsequent EMF by reducing the overlap between the rotor and the stator in an axial air gap motor. The magnet blocks of the rotor are mounted on the rotor, such that an increase in speed during operation results in an increase in centrifugal force on the blocks of the magnet, causing them to move out of the center of the motor. This outward movement results in a reduction in the overlap between the magnet block and the stator, thereby reducing the flow link and the subsequent generated EMF. As a result, the machine can spin at higher speeds. High-speed electric machines (for example, high rpm) are almost always manufactured with low polar counts, for fear that the magnetic materials in electrical machines operating at higher frequencies, experience excessive core losses that contribute to the inefficient engine design. This is mainly due to the fact that the soft material used in the vast majority of current engines is a silicon-iron alloy (Si-Fe). It is well known that the losses resulting from the change of a magnetic field at frequencies greater than about 400 Hz in conventional materials based on Si-Fe cause the material to heat up, sometimes at the point where the device can not be cooled by any acceptable means. A number of applications in current technology, including widely diverse areas such as high-speed machines and tools, aerospace motors and actuators, and compressor drives, require electric motors operable at high speeds, often greater than 15,000-20,000 rpm, and in some cases up to 100,000 rpm. To date, it has proven very difficult to provide easily manufactured electrical devices at low cost, which take advantage of low loss materials. Previous attempts to incorporate low loss materials into conventional machines failed in general, since early designs typically relied merely on replacing the new soft magnetic materials, such as amorphous metal, with conventional alloys, such as silicon-iron, in the Magnetic cores of the machines. The resulting electrical machines have sometimes provided increased efficiencies with less loss, but these in general suffer from an unacceptable reduction in energy output, and significant increases in cost, associated with the handling and formation of the amorphous metal. As a result, they have not achieved commercial success or market penetration. Thus, there remains a need in the art for highly efficient axial air gap electrical devices, which take full advantage of the specific characteristics with the low loss material, thereby eliminating the disadvantages associated with conventional air gap machines. Ideally, an improved machine would provide higher conversion efficiency between mechanical and electrical energy forms. Improved efficiency in the generation of machines powered by fossil fuels would concomitantly reduce air pollution. The machine would be smaller or lighter and would satisfy more demanding requirements of torque, energy and speed. The cooling requirements could be reduced. Motors that operate from battery power, would operate for longer. In addition, there is still a need for devices that can operate efficiently either in the constant torque mode or, with proper post EMF control, in the constant energy mode. In addition, machines in which the torque ripple and plugging, and the concomitant electrical ripple, are reduced, for example, by the increased polar count, are desired. BRIEF DESCRIPTION OF THE INVENTION The present invention provides a dynamoelectric axial air gap machine, comprising a first stator and a second stator, and a rotor positioned axially between the stators, and supported for rotation about an axis. The stators have first and second respective groups of windings placed on them. The second stator is selectively miner with respect to the first stator such that the second stator is displaced from the first stator. The stators comprise toroidal cores comprising laminated layers composed of a material selected from the group consisting of amorphous and nanocrystalline metals and optimized iron-based alloy. In some embodiments, the alignment of the stators is adjustable by the misalignment means. The use of soft magnetic materials, advanced low loss in the core, provides significant flexibility in the design, since a wider range of polar counts, and switching frequencies are possible, while maintaining a wide range of possible speeds of operation, high operating efficiency and high energy density. In a further aspect, the windings of the stators are separately connected to the first and second respective full-wave diode bridges. As a result of the displacement of the stators, the waveforms of the individual windings are relatively shifted in phase. The bridge outputs are connected to each other to provide the collective bus voltage of direct current (DC). The resulting waveform has reduced electrical current ripple compared to the waveform obtained without displacement, and with multiple stator waveforms connected in series, allowing the filtering circuitry to be simplified. The displacement of the stators also allows the motor to be operated in a manner that allows the rear EMF of the motor and / or that the undulation of the torque produced within the operation is reduced. The invention also provides techniques for reducing the elimination of the undulation of the torque during the operation of the electrical device, by controllably misaligning one or more stators of the device relative to a reference stator. In addition, a double full-wave diode bridge array is described to help reduce current ripple on the collective direct current bus of the electrical machine. In the prior art, a transmission with selectable or adjustable gear ratio has been employed to provide an output shaft speed greater than the maximum motor speed, which is generally limited by the counter electromotive force (EMF force). A reduction in the gear. A gear reduction allows a higher output speed to be exchanged for a lower, available torque. On the other hand, the frictional losses inherent in the transmission system, the mechanical simplification, the reliability considerations, provide a strong impetus for machines that avoid transmission among themselves. The method of misalignment of the stators according to the present invention provides a motor that is capable of changing from a constant torque mode to a constant energy mode, for example, operating at constant voltage, thereby providing speeds that go beyond a base speed without any transmission or gear. In still another aspect, there is provided an axial air gap machine comprising a dynamoelectric axial air gap machine and electronic power means for interconnecting and controlling the machine and which are operably connected thereto. Examples of electrical machines that have to be produced and operated in accordance with the invention include, but are not limited to, electric motors, generators and generative motors. One or more of the electrical devices could be a component in a composite device or system. An example of such a composite device is a compressor comprising one or more electric motors, where one or more electric motors can be integral with the fan. BRIEF DESCRIPTION OF THE FIGURES The invention will be more fully understood, and the additional advantages will become apparent when reference is made to the following detailed description of the preferred embodiments of the invention and of the appended figures, in which like reference numerals denote elements of the invention. similar throughout the various views and in which: Figure 1 illustrates a view of a face of an axial air gap type stator; Figure 2 illustrates a view of a face of an axial air gap type rotor; From figures 3 to 9 illustrate the results of the superposition of sinusoidal waveforms from two stators connected in series in the rotor position, for different degrees of misalignment between the two stators; Figure 10 illustrates the result of the superposition of two types of trapezoidal waveforms from two stators connected in series and misaligned by half complete pole separation; Figures 11 and 12 illustrate the disturbance of the torque, at zero electric current for misaligned stators with% slot separation; Figure 13 illustrates a top view and side view of one embodiment of an electrical device comprising a simple motor and two stators; Figures 14 and 15 illustrate two different positions of an external control system for controlling the rotational misalignment of one of the stators; Figures 16, 17 and 18 illustrate the operation of a speed-dependent control, mechanical governor style for the rotational misalignment of a stator; Figures 19 and 20 illustrate a stator that is mounted on springs, for the control of rotational misalignment; Figures 21 and 22 illustrate a stator mounted on a shaping material for the control of rotational misalignment; Figure 23 shows a graph of the parameters of a generator during the operation according to the invention; Figure 24 shows a comparison of a typical single-phase alternating current (AC) voltage, generated from an electric machine, including rectified voltage, and rectified three-phase voltage, including ripple; Figure 25 shows a full-wave diode bridge, of the prior art, typical used for connection in an electrical machine; Figure 26 shows a rectified three-phase voltage, of the prior art, typical from the arrangement of Figure 25; Figure 27 shows a detail of the typical direct current voltage ripple associated with the waveform of Figure 26; Figure 28 shows the typical average direct current energy in association with an electrical machine arrangement such as that shown in Figure 25; Figure 29 shows the double full-wave diode bridges, in association with double stators of an electrical machine; Figure 30 shows the rectified three phase voltage from the arrangement of Figure 29; Figure 31 shows a detail of the direct current voltage ripple, associated with the waveform of Figure 30; and Figure 32 shows the average direct current energy associated with the electrical machine arrangement of Figure 29. DETAILED DESCRIPTION OF THE INVENTION Preferred embodiments of the present invention will be explained in more detail hereafter with reference to the accompanying figures. . In one aspect, the present invention relates to an electrical axial gap device, such as a brushless motor, having one or more rotors and two or more stators, the stators having magnetic cores made of a soft, low magnetic material. loss, capable of high frequency operation. Preferably, the magnetic cores of the stators are made using a material in the form of a thin strip or strip consisting essentially of an amorphous metal or nanocrystalline flax, or an optimized soft magnetic alloy based on iron. Iron-based, grain-oriented and non-grain-oriented materials, which have lower core losses than iron-based, crystalline, electric-based steel materials conventionally used in dynamo-electric machines, and which are often higher Saturation induction that amorphous or nanocrystalline materials are collectively referred to herein as "magnetic materials based on iron, optimized. "The inclusion of amorphous, nanocrystalline or optimized magnetic materials based on iron in the present electrical device makes it possible for the frequency of the machine to be increased without a corresponding increase in the loss of the core, thus producing an electrical device. In addition, this ability to increase the switching frequency allows for higher pole count designs without reducing the maximum allowable machine speed.One or more rotors can be permanent magnet type rotors. However, another type of rotor known in the art is also applicable in the practice of the present invention.

Amorphous metals Amorphous metals, which are also known as metallic glasses, exist in many different compositions, suitable for use in the present engine. The metallic glasses are typically formed of a molten alloy of the required composition, which is rapidly quenched from the melt, for example, by cooling at a rate of at least about 10 ° C / sec. These do not show wide-range atomic order, and they have X-ray diffraction patterns that show only diffuse haloes, similar to those observed for inorganic oxide glasses. A number of compositions having suitable magnetic properties are described in U.S. Patent No. RE32,925 to Chen et al. The amorphous metal is typically supplied in the form of extended lengths of thin ribbon (e.g., a thickness of at most about 50 μm) of width of 20 cm or more. A useful process for forming metal strips of indefinite length is described in U.S. Patent No. 4,142,571 to Narasimhan. An exemplary amorphous metal material suitable for use in the present invention is METGLAS® 2605 SAI, sold by Metglas, Inc., Conway, SC in ribbon form of indefinite length and up to about 20 cm in width and 20-25 μm in width. thickness (see http: //www.metglas.com / products / page5_l_2_4. htm). Other amorphous materials with the required properties can also be used. Amorphous metals have a number of characteristics that must be taken into account in the manufacture and use of magnetic implements. Contrary to most soft magnetic materials, metallic glasses are hard and brittle, especially after the heat treatment typically used to optimize their soft magnetic properties. As a result, many of the mechanical operations commonly used to process soft magnetic materials, conventional, for engines, are difficult or impossible to perform on amorphous metals. The material produced by stamping, pung or cutting in general results in unacceptable wear of the tool, and is virtually impossible on the heat-treated brittle material. Conventional drilling and welding, which are often performed with conventional steels, are also usually excluded. In addition, amorphous metals exhibit a lower saturation flux density (or induction) than conventional Si-Fe alloys. The lower density of flow ordinarily results in lower energy densities in engines designed according to conventional methods. Amorphous metals also have lower thermal conductivities than silicon and iron alloys. Since thermal conductivity determines how heat can be easily conducted through a material from a hot site to a cold site, the lower value of thermal conductivity needs careful engine design to ensure proper disposal of waste heat that arises of the losses in the core of the magnetic materials, the ohmic losses in the windings, friction, winding and other sources of loss. Improper disposal of the waste heat, in turn, could cause the engine temperature to rise unacceptably. It is likely that excessive temperature causes primary failure of the electrical insulation or other components of the motor. In some cases, overheating could cause a shock hazard or a catastrophic fire or other serious danger to health and safety. Amorphous metals also show a higher magnetostriction coefficient than certain conventional materials. A material with a lower magnetostriction coefficient undergoes smaller dimensional change under the influence of a magnetic change, which in turn could probably reduce the audible noise coming from a mae, as well as making the motor more susceptible to the degradation of its magnetic properties as a result of the stresses induced during the manufacture or operation of the machine. Despite these challenges, an aspect of the present invention provides an engine that successfully incorporates soft, advanced magnetic materials and allows the operation of the motor with high frequency excitation, for example, a switching frequency greater than about 400 Hz. The construction techniques for the manufacture of the engine are also provided. As a result of the configuration and use of advanced materials, especially amorphous metals, the present invention successfully provides a motor that operates at high frequencies (defined as switching frequencies greater than about 400 Hz) with a high polar count. Amorphous metals show much less hysteresis losses at high frequencies, which result in much lower core losses. Compared to Si-Fe alloys, amorphous metals have much lower electrical conductivity and are typically much thinner than ordinary Si-Fe alloys, which are often 200 μm thick or more. These two characteristics promote lower parasitic current core losses. The invention successfully provides an engine that benefits from one or more of these favorable attributes and thereby operates efficiently at high frequencies, using a configuration that allows advantageous qualities of the amorphous metal to be obtained, such as reduced core loss, time that the challenges faced in previous attempts to use advanced materials are avoided. Nanocrystalline Metals Nanocrystalline materials are polycrystalline materials with average grain sizes of approximately 100 nanometers or less. Attributes of nanocrystalline metals compared to conventional coarse-grained metals generally include increased strength and hardness, increased diffusivity, improved ductility and firmness, reduced density, reduced modulus, higher electrical resistance, increased specific heat, higher coefficients of thermal expansion, lower thermal conductivity, and superior soft magnetic properties. The nanocrystalline metals also have a saturation induction in general somewhat higher than most amorphous metals based on iron. The nanocrystalline metals can be formed by a number of techniques. A preferred method comprises initially emptying the required composition as an indefinite-length metal glass strip, using techniques such as those shown hereinabove, and forming the ribbon into a desired configuration, such as a rolled shape. After this, the amorphous material is initially heat treated to form a nanocrystalline microstructure therein, this microstructure is characterized by the presence of a high density of grains having an average size of less than about 100 nm, preferably less than about 50 nm, and more preferably about 10-20 nm. The grains preferably occupy at least 50% of the volume of the iron-based alloy. These preferred materials have low core loss and low magnetostriction. The latter property also makes the material less vulnerable to the degradation of the magnetic properties by the stresses resulting from the manufacture and / or operation of a device comprising the component. The heat treatment necessary to produce the nanocrystalline structure in a given alloy should be carried out at a higher temperature, or for a longer time than would be necessary for a heat treatment designed to preserve a microstructure therein. substantially completely crystalline. The representative nanocrystalline alloys, suitable for use in the construction of magnetic elements for the present device, are known, for example the alloys described in U.S. Patent No. 4,881,989 to Yoshizawa and U.S. Patent No. 5,935,347 to Suzuki et al. Such materials are available from Hitachi Metals and Alps Electric.

Preferably, the nanocrystalline metal is an iron-based material. However, the nanocrystalline metal could also be based on or include other ferromagnetic materials, such as cobalt or nickel. • Optimized Iron-Based Alloys The present machines can also be built with low loss, optimized iron based crystalline alloy material. Preferably, such material is in the form of a strip having a thickness of less than about 125 μm, much thinner than steels conventionally used in engines, having thicknesses of 200 μm or more, and sometimes as much as 400 μm or more . Grain-oriented and non-oriented materials can be used. As used herein, an oriented material is one in which the major crystallographic axes of the constituent crystallite grains are not randomly oriented, but are predominantly correlated along one or more preferred directions. As a result of the above microstructure, an oriented strip material responds differently to the magnetic excitation along different directions, while an unoriented material responds isotropically, for example, substantially with the same response to excitation throughout. any direction in the plane of the strip. The grain oriented material is preferably placed in the present motor with its magnetization direction substantially coincident with the predominant direction of the magnetic flux. As used herein, conventional Si-Fe refers to silica-iron alloys with a silicon content of about 3.5% or less by weight. The limit of 3.5% by weight of silicon is imposed by the industry due to the poor properties of the metallic work material of Si-Fe alloys with higher silicon contents. The core losses of conventional Si-Fe alloy grades resulting from operation in a magnetic field with frequencies greater than about 400 Hz are substantially higher than those of the low loss material. For example, in some cases the conventional SiFe losses can be as many as 10 times those of the amorphous metal appropriate to the frequencies and flow levels found in the machines operating under the frequency and flow levels of the present machines. As a result, conventional material, under high frequency operation, could be heated to a point at which the conventional machine could not be employed by any acceptable means. However, some grades of silicon-iron alloys, referred to herein as Si-Fe, could be directly applicable to the production of a high-frequency machine. The iron-based optimized alloys useful in the practice of the present invention include silicon-iron alloys of grades comprising more than 3.5% silicon by weight, and preferably more than 4%. The non-oriented iron-based material used in the construction of machines according to the invention preferably consists essentially of an iron-silicon alloy in an amount in the range of about 4 to 7.5% by weight of silicon. These preferred alloys have more silicon than conventional Si-Fe alloys. Also useful are Fe-Si-Al alloys such as Sendust. The most preferred non-oriented optimized alloys have a composition consisting essentially of iron with about 6.5 ± 1% by weight of silicon. More preferably, alloys having approximately 6.5% silicon show near zero values of the saturation magnetostriction, making them less susceptible to degradation of the damaging magnetic property due to the stresses encountered during the construction or operation of a device containing the material . The objective of the optimization is to obtain an alloy with improved magnetic properties, including reduced magnetostriction and especially core losses. These beneficial qualities are obtainable in certain alloys with increased content of silicon, prepared by suitable manufacturing methods. In some cases, these optimized silicon-iron alloys are characterized by core loss and magnetic saturation similar to those of the amorphous metal. However, alloys containing more than about 4% by weight of silicon, are difficult to produce by conventional means, due to their fragility due to the short interval ordering. In particular, the conventional rolling techniques used to make the conventional Si-Fe are, in general, incapable of making optimized Si-Fe. However, other known techniques are used to produce optimized Si-Fe. For example, a suitable form of Fe-6 .5 Si alloy is supplied as magnetic strips of 50 and 100 μm thickness by JFE Steel Corporation, Tokyo, Japan (see also http: // www. Jf e-steel. . jp / en / products / electrical / supercore / index. html). The Fe-6. 5% If produced by rapid solidification processing, as described in U.S. Patent No. 4, 865, 657 to Das et al. and U.S. Pat. No. 4, 265, 682 to Tsuya et al. It can be 'also used. The fast solidification processing is also known for the preparation of Sendust and related Fe-Si-Al alloys.

Rotor materials The rotor of the present machine can comprise any type of permanent magnet. Rare earth transition metal alloy magnets, such as samarium-cobalt magnets, other cobalt-rare earth magnets, or rare earth-transition metal-metalloid magnets, eg, NdFeB magnets, are suitable . Alternatively, the magnet structure of the rotor comprises any other sintered permanent magnet material, bonded with plastic or ceramic. Preferably, the magnets have a product of high maximum BH energy, high coercivity, and high saturation magnetization, together with a linear, second quadrant normal magnetization curve. More preferably, transition metal alloy magnets of the rare earth, oriented and sintered earth alloys are used, since their higher energy product increases the flow and therefore the torque, while allowing the volume of the material of expensive permanent magnet, be reduced to a minimum. In alternative embodiments, the rotor includes one or more electromagnets. Axial Air Gap Electrical Device Comprising Low Loss Materials The methods of the invention apply to electrical devices comprising two or more stator structures axially positioned adjacent to one or more rotor structures. In an illustrative embodiment comprising a single rotor and two stators, the stators are placed on opposite sides of the rotor on a common axis. In preferred embodiments, the two or more stators comprise high frequency, low loss materials, such as amorphous or nanocrystalline metals, or optimized iron-based alloy, grain-oriented iron-based material, or non-oriented iron-based material. grain. The stator preferably includes a metal core formed by spirally winding the high frequency, low loss strip material in a toroid. This toroid has the form of a circular cylindrical shield, generally straight, having an internal diameter and an external diameter, when observed in the axial direction. The region of the annular end surface extending radially from the inside to the outside diameter, and circumferentially around the entire toroid, defines a surface area. The metal core extends axially, defining a toroid height. The coiled core is thereafter machined with grooves, which are generally radially directed, to form the stator. The depth of the groove is axially extended only by a partial path through the height of the toroid. The grooves reduce the total surface area of the metal core. Figure 1 illustrates a view of a face of the stator 10, showing the internal diameter (d) and the external diameter (D) of the stator. Also illustrated are slots 12 of the outer width stator (w) which are machined into the metal core to form the stator. The portion of the annular region left after the elimination of the grooves, is the total area (TA), also referred to as the amorphous metal area (AMA) for the modalities in which the high frequency low loss material is a amorphous metal. Because the grooves extend from the inner diameter d to the outer diameter D, the internal diameter d of the stator core in the grooved portion of the toroid is not continuous. After the spaces in the groove have been removed, the remaining part of the annular region of the core extending to the depth of the groove is called a tooth 14. There is an equal number of teeth and grooves. The slots 12 are wound with windings of conductive stators (not shown in Figure 1) according to a preselected winding pattern for a given electrical device design. A preferred winding scheme involves one coil per prong 14. Each coil ordinarily comprises multiple turns of the conductor cable. This configuration provides the least amount of stator misalignment, required to achieve the maximum benefit according to the methods of the present invention. However, any winding arrangement known in the art is applicable. Stator constructions suitable for use in the practice of the present invention are also provided by commonly assigned United States Patent Application Serial No. 10 / 769,094, filed January 30, 2004, the application of which is incorporated in the present in its entirety, by reference. Figure 2 illustrates a one-sided view of an axial-type rotor structure that is positioned for rotation between two or more stators of the electrical device.

The rotor and the stators are substantially coaxial. In the preferred embodiment, the rotor 20 comprises a plurality of magnets 22, which have alternating polarity and placed and spaced circumferentially around the rotor. The different parameters of the rotor magnets, such as position, angle, inclination, shape, etc., could be varied as is known in the art. However, the methods of the present invention also apply to the resulting electrical device. In a preferred embodiment, the rotor comprises a plurality of permanent magnets. In some embodiments, the images of the rotor extend through the thickness of the rotor, while in others they do not. Preferably, the rotor arrangement is a disc or axial type rotor that includes circumferentially spaced high energy product permanent magnets, for example, rare earth-transition or rare earth metal-transition metal-metal magnets, such such as SmCo, iron with rare earths (NdFeB), or iron-cobalt-rare earth magnets (NdFe, CoB), each having opposite ends that define the north and south poles. The rotor 20 and its magnets 22 are supported for rotation about an axis of the motor, for example, on an axis or any other suitable arrangement such that the poles of the magnets are accessible along a predetermined path adjacent to two or more stators. Ordinarily, the shaft is supported by bearings of any known type, suitable, for rotating machines. The area of the magnet on the rotor has an outer diameter and an internal diameter. In a preferred embodiment, for an axial air gap type rotor, the external diameter and the internal diameter of the magnets 22 are substantially identical to those of the stators 10. If the external diameter of the magnets 22 is greater than that of the stators 10, then the outer portion of the rotor does not contribute appreciably to the operation. If the outer diameter of the rotor 20 is smaller than that of the stators 10, the result is a reduction in the operation of the electrical device. In any case, some of the hard or soft magnetic material present in the machine, which increases the cost and weight, but without improving the operation. In some cases, the extra material even decreases the operation of the machine.

Proportions Slot Per Phase by Pole In the present invention, a pole refers to the non-time-varying magnetic field, also referred to herein as a DC field, which interacts with a changing magnetic field, for example, one that varies in magnitude and direction with time and position. Therefore, in the preferred embodiments, the permanent magnets mounted on the rotor provide the DC field, and therefore the number of magnetic poles non-variant in time, are referred to herein as DC poles. In other embodiments, a DC electromagnet can provide the DC field. The electromagnets of the stator windings provide the changing magnetic field, for example, one that varies with time and position. The slot value per phase per pole (SPP) of an electric machine is determined by dividing the number of slots 12 of the stator by the number of phases in the stator winding and the number of DC poles (SPP = slots / phases / poles). In calculating the SPP value, a pole refers to the DC field that interacts with a changing magnetic field. A slot refers to the spacing between the alternating teeth of the stator of the present machine. The techniques of the present invention are applicable to electrical devices with any SPP value. Beneficially, the design of the present machine provides considerable flexibility in the selection of an optimal SPP ratio. In preferred embodiments, the permanent magnets 22 provide the DC field, and therefore the number of DC poles. In other embodiments, a DC electromagnet structure provides the DC field. The electromagnets of the stator windings provide the changing magnetic field, for example, one that varies with time and position. Conventional machines are often designed to have an SPP ratio of 1 to 3 to obtain acceptable functionality and noise levels and to provide smoother output due to better distribution of the winding. However, designs with a lower SPP value, for example 0.5, have been sought to reduce the effect of extreme turns. The extreme turns are the portions of the cable in the stator that connect the windings between the slots. Although such a connection is, of course, required, the extreme turns do not contribute to the torque and to the energy output of the machine. In this sense these are undesirable, since they increase the amount of cable required, and contribute to ohmic losses to the machine, while not providing benefit. Therefore, one goal of the engine designer is to minimize extreme turns and provide a motor with manageable noise and rattle. On the other hand, preferred implementations of the present engine allow a reduced proportion of SPP, together with desirably low noise and rattling. Such benefit is obtained by operating with a high polar and slot count. These options were not feasible in the previous machines, because the required increase in the switching frequency is unacceptable without the use of advanced, low loss stator materials. For some applications, it is advantageous to build a motor with fractional value of SPP, since such motor can employ pre-formed coils placed around a single stator tooth. In different embodiments of the present machine, the SPP ratio is an integral ratio, such as 0.25, 0.33 or 0.5. SPP values of 1.0, or even greater than 1.0 are also possible. Preferably, the SPP values are in the range of 0.25 to 4.0. However, more preferred embodiments of the present machine are beneficially designed with an SPP ratio of 1 or less, and even more preferably 0.5 or less. It is possible to wire multiple slots in a common magnetic section, providing an SPP greater than 0.5. This is the result that there is a greater number of stator slots than the rotor poles, resulting in a distributed winding. An SPP value less than or equal to 0.5 indicates that there are no distributed windings. A convention in the industry is to include windings distributed in the stator. Ordinarily, prior art machines designed with distributed windings have many slots per pole, resulting in operation at a lower frequency. As a result, in conventional machines that have SPP of 0.5 or less, and operate at low frequency, there will also be a low pole count and a high rattle, difficult to control. On the other hand, the use of advanced magnetic materials in the present machine, allows the switching frequency to be high, so that low SPP values can be maintained, while also minimizing rattling and without reducing the speed of the machine. However, while the methods of the present invention are applicable to an electrical device with SPP values less than 0.5 (for example 0.25), practical considerations sometimes make such configuration less desirable, including increased reactance of the machine to a higher switching frequency required, increased leakage flow increased from the rotor magnets, and the mechanical support necessary to accommodate the rotor magnets, which are smaller and numerous, is often less advantageous for other important parameters of the electrical device. On the other hand, increasing the SPP value effectively increases the pole separation of the machine. For example, multiple stator slots 12 can be wired in a common magnetic section, which corresponds to a slot per phase per pole (SPP) value greater than 0.5. While such a configuration is applicable in the practice of the invention, the amount of stator movement that is desirable increases, which could be a disadvantage in some applications. Although the present machine can be designed and operated as a single-phase device, or a polyphase device with any number of phases and a commensurate number of windings on each of the stators, a three-phase machine with three-phase windings is preferred according to the industry convention, and provides efficient use of hard and soft magnet materials, together with a good energy density. Modes with SPP ratios of 0.5 are particularly suitable for three phase applications. For example, in a three-phase machine, with a slot / well / phase ratio = 0.5, the number of rotor poles is two thirds the number of stator slots, with the number of slots being a multiple of the number of phases. While the machine is usually wired in a three-way configuration according to industry convention, a delta configuration can also be employed.

High Count Polo Design, High Frequency Utilizing Low Loss Materials In specific embodiments, the present invention also provides an axial electrical air gap device with a high pole count operating at high frequencies, for example, a switching frequency greater than about 400 Hz. In some cases, the device is operable at a switching frequency in the range of about 500 Hz to 3 kHz or more. Designers have ordinarily avoided high pole counts for high-speed motors, since conventional stator core materials, such as Si-Fe, can not operate at proportionally higher frequencies, necessitated by high pole counts. In particular, known devices using Si-Fe can not be changed at magnetic frequencies significantly above 400 Hz due to the core losses resulting from the changing magnetic flux within the material. Above that limit, core losses cause the material to heat up to the point where the device can not be cooled by any acceptable means. Under certain conditions, the heating of the Si-Fe material can even be severe enough so that the machine can not be cooled in any way, and will self-destruct. However, it has been determined that the low loss characteristics of amorphous, nanocrystalline and non-grain oriented metals allow much higher switching ratios than conventional Si-Fe materials. While, in a preferred embodiment, the choice of the amorphous metal alloy, such as the METGLAS® 2605SA1 alloy, eliminated the limitation of the system because the heating to high-frequency operation, the design of the rotor and the complete configuration of the motor have also been improved for better exploitation of the properties of the amorphous material. The ability to use much higher excitation frequencies allows the present machines to be designed with a much wider range of possible pole counts. The number of poles in the present devices is a variable based on the allowable size of the machine (a physical constraint) and on the expected operating range. Subject to allowable excitation frequency limits, the number can be increased until the magnetic flux leak increases to an undesirable value, or operation begins to decrease. There is also a mechanical limit presented by the construction of the stator on the number of poles of the rotor, since the stator slots must coincide with the magnets of the rotor. In addition, there is a mechanical and electromagnetic limit in coincidence with the number of slots that can be made in the stator, which in turn is a function of the size of the structure of the machine. Some limits can be established to determine the upper limits of the number of slots for a given stator structure, with an adequate balance of copper and magnetic material, which can be used as a parameter in the elaboration of axial air gap machines, of good functioning. The present invention provides motors with approximately 4 or 5 larger numbers of poles than the industrial values for most machines. As an example, for a typical industrial motor having 6 to 8 poles, for motors at speeds of approximately 800 to 3600 rpm, the switching frequency is approximately 100 to 400 Hz. The switching frequency (CF) is the rotating speed multiplied by the number of pole pairs, where the pole pairs is the number of poles divided by two, and the rotation speed is in units of revolutions per second (CF = rpm / 60 x pole / 2). Also available in the industry are devices with 16 or more poles, but with speeds of less than 1000 rpm, which still corresponds to a frequency less than 40 Hz. Alternatively, motors with a relatively low pole count (for example less than 6 poles) are also available, and with speeds up to 30,000 rpm, which still have a switching frequency of less than about 400 Hz. In representative embodiments, the present invention provides the machines that are 96 poles, 1250 rpm, at 1000 Hz; 54 poles, 3600 rpm, at 1080 Hz; 4 poles, 3000 rpm, at 1000 Hz; and 2 poles, 60000 rpm, at 1000 Hz. The high frequency motors of the invention can operate at frequencies of approximately 4 to 5 times higher than known axial air gap motors, made with conventional materials and designs. The present engines are more efficient than typical engines in the industry when operated in the same speed range, and as a result provide greater speed options. The present configuration is particularly attractive for the construction of very large motors. By using a combination of a high pole count (for example at least 32 poles) and a high switching frequency (for example, a frequency of 500 to 2000 Hz), very large machines can be constructed according to the invention, from a way that combines high energy efficiency, high energy density, ease of assembly, and efficient use of soft and hard magnetic materials, expensive.

Thermal Properties One of the features that limits the output efficiency of the device in all electrical machines, including those that use conventional Si-Fe alloys, and those that use optimized Si-Fe alloy, nanocrystalline, amorphous, Fe-based metals grain-oriented or non-grain-oriented Fe, is the loss of energy for waste heat. This waste heat comes from a number of sources, but predominantly from the ohmic losses, the losses of film effect and proximity in the windings, the rotor losses from eddy currents in the magnets and other components of the rotor, and the loss of the core from the stator core. Due to the large amounts of waste heat generated, conventional machines soon reach the limit of their ability to discard waste heat. The "continuous energy limit" of conventional machines is often determined by the maximum speed at which the machine can operate continuously, while still dissipating all the waste heat that is generated. The limit of continuous energy is a function of the current. In high-frequency, high-frequency electrical pole devices, optimally applicable in the practice of the present invention, less waste heat is generated due to the optimized Si-Fe alloy, nanocrystalline, amorphous, to the materials Iron-based grain-oriented, or non-grain-oriented iron-based materials, which have lower losses than conventional Si-Fe. The designer can exploit the low loss characteristics of these materials by increasing the frequency, speed and energy, and then correctly balancing and "bartering" the low core loss versus the ohmic loss. In general, for the same energy as conventional machines, high-frequency, high-frequency electric devices, optimally applicable in the present invention, show lower loss, and therefore higher torques and speeds, and can This mode achieves higher continuous speed limits than conventional machines.

Improved Efficiency One of the advantages of high pole count, high frequency electric devices, optimally applicable in the present invention is the ability to maximize device efficiency, while maintaining cost effectiveness. Efficiency is defined as the useful energy output of the device divided by the energy input. The high-frequency, high-frequency pole-counting devices optimally applicable in the present invention operate simultaneously at higher switching frequencies, with high pole counting, resulting in a more efficient device having low core losses and high energy density. The high frequency limit of 400 Hz is an industrial standard beyond which there are few, if any, practical applications. The operation and increased efficiency of the high-frequency, high-frequency, pole-counting electrical devices optimally applicable in the present invention is not simply one. inherent characteristic of the replacement of conventional Si-Fe with amorphous metal. A number of designs have been proposed, but they have encountered some malfunction (including overheating and lower output power). It is believed that this feature has arisen largely as a result of the mere application of new materials (eg, amorphous metals) and production methods in the ways they were designed for, and suitable for, conventional material (Si -Fe that contains 3.5% or less of Si by weight). Early operational failure, combined with the perceived cost of amorphous metal processing in engines, caused all companies in the industry to abandon research. The high-frequency, high frequency, pole-counting electric devices optimally applicable in the present invention overcome the malfunctions of the prior art, through the design of a rotating electrical device that exploits the properties of the Si alloying materials. -Fe, faith-based or grain-based Fe non-grain oriented, amorphous, nanocrystalline, optimized. They also provide construction methods compatible with the physical and mechanical characteristics of the various improved materials. These designs and methods provide machines that possess some or all of the various advantageous qualities, including operation at switching frequencies greater than 400 Hz, with a high pole count, at high efficiency and with a high energy density. While other conventional methods have been able to provide motors with at most one or two of the four qualities, among the modalities provided herein, are the high-frequency, high-frequency pole-counting devices, which show some, and preferably all, the four qualities simultaneously. In many modalities, the current high-frequency, high-frequency electric pole machines show good efficiency losses. A greater contribution to improvement results from significantly reduced hysteresis losses. As is known in the art, the hysteresis losses result from the impeded motion of the domain wall during the magnetization of all soft magnetic materials. Such losses are generally higher in conventionally used materials, such as grain-oriented, conventional Si-Fe alloys and non-oriented electric and motor steels, the improved materials preferably used in the present machines. The high losses, in turn, can contribute to the overheating of the core. As a result of the increased efficiency, the high-frequency, high frequency, pole-counting electric devices, optimally applicable in the present invention, are capable of achieving a larger continuous speed range. Conventional motors are limited in that they can provide either low torque for high speed (low energy) intervals, or high torque for low speed intervals. High frequency, high frequency pole counting devices, optimally applicable in the present invention, successfully provide electrical devices with high torque for high speed intervals.

Misalignment of the Stators In one aspect of the present invention, methods are provided for selectively controlling one or more rotating stators of the electrical machine, relative to one or more reference stators. By "selective alignment" or misalignment "is meant an angular displacement or misalignment of the teeth and grooves of one or more rotating stators of the present machine, with respect to the corresponding teeth and slots of one or more reference stators, with the Rotating reference stators and the associated rotors are all coaxially positioned In some embodiments, one or more reference stators of a machine are placed in a fixed position relative to the machine housing, which in turn is ordinarily secured to the additional elements of the mechanical system to which the machine is connected Alternatively, the reference and rotary stators can be made angularly rotatable with respect to the housing, to effect the desired misalignment - In any alternative, it is understood that the misalignment is measured relatively between the stators, and not with reference to the structure or housing of the engine. The present methods of selective alignment are particularly applicable to axial air gap motors and generators. The controlled misalignment of one or more rotating stators of the electric machine, results in the regulation of different parameters of the electric machine. For example, the consideration of the stator can be adaptively adjusted to maintain a substantially constant advantage characteristic, or to reduce or substantially eliminate the ripple of the torque. In the methods of the invention, at least one of the stators in an axial air gap machine is intentionally driven to rotate axially relative to a reference stator about its axis, resulting in rotational misalignment (eg, a stator). it is azimuthly "displaced" with respect to the other stator). As a result, the sinusoidal waveforms (eg, sine or near sine) of the field pattern of the intentionally misaligned stators are not synchronized (eg, they are not in electric phase, optimal, substantially coincident), in the position of the rotor. Since the generated electromotive force is a function of the superposition of the sinusoidal waveforms generated by the stators, any change in the generated, superimposed waveforms leads to a change in the characteristics of the generated EMF, of the electrical device. Although many embodiments of the invention are illustrated by an electrical device comprising a rotor and two stators, the methods of the invention are applicable to electrical devices that comprise any number of stators and that share any number of rotors. For example, the machine may comprise two rotors on a common axis, each located between axially adjacent stators, with their teeth facing the respective opposite sides of the rotor between them. In some of these modalities, the rotors are joined in a common axis.

Rotor Pole Separation and Stator Slot Separation The desired degree of misalignment of the stators in various embodiments of the methods of the invention is defined in relation to either a rotor pole spacing or a stator slot spacing. . A slot separation is defined as the rotational distance between the centers of the adjacent stator electrical slots. Figure 1 illustrates a slot separation for a stator with 18 electrical slots. A slot separation is conventionally measured in degrees, however, radians or other desired units of angular measurement, known in the art, are also applicable. A pole separation is defined as the rotational distance measured between the centers of the rotor magnetic poles, adjacent. Figure 2 illustrates a pole spacing for a rotor comprising 12 rotor magnets. While a pole spacing is also conventionally expressed in the units of degrees, radians or other desired, angular measuring units known in the art are also applicable. The separation of the pole and the stator separation can be specified in mechanical or electrical angular units, such as degrees. Electrical ratings are measured in relation to the period of each switching cycle, during which the machine axis (in synchronous operation) rotates through a complete revolution in a two-pole machine, or in a fraction thereof in machines that They have more than 2 poles. More commonly, misalignment in applications where the undulation of torque and rattle will be minimized, are measured in mechanical degrees based on slot separation. Applications where the counter electromotive force is to be controlled, employ mechanical degrees based on pole separation to measure the misalignment drive of the stator, but electrical ratings for the desired electrical response. The applications of minimization of undulations of the collective bar of DC are ordinarily specified in electric grains in relation to the pole separation, based on half of the natural 6: 1 ratio of the ripple frequency of the collective bar DC to the switching frequency. In the practice of the invention, at least one stator is designated a reference stator. That is, the degree of misalignment of one or more rotating stators is measured relative to the reference stator. In some embodiments of the invention, one or more reference stators are held fixed, while one or more rotating stators are allowed to rotate by a desired amount relative to one or more reference stators. The amount of this relative ratio can be from 0 degrees (minimum) to full pole separation (maximum), or a full slot separation (maximum), depending on the desired degree of misalignment. The embodiments are also provided in which one or more reference stators and one or more rotating stators move to achieve the desired amount of rotational misalignment, eg, relative phase differences. Some embodiments of the present dynamo-electric machine employ more than two stators and one rotor. In such machines, at least one stator is designated as the reference stator, and the other stators are rotating stators that can not be commonly aligned but displaced from the reference stator. More preferably, the rotating stators are independently alignable.

Although a means of alignment in such a mode would require separate drive systems for each adjustable stator, additional flexibility would be presented. For example, in a four-stator, two-rotor mode, three stators could be replaced from the reference by a common preferred amount to reduce the rattle of the torque. To control the counter electromotive force, the rotating stators could be adaptively controlled to achieve the best reduction consistent with the desired acceleration response, as may be desirable in a traction motor or regenerative motor application. In a machine where the electrical ripple of the collective bar DC is to be reduced to a minimum, the additional degrees of freedom allow the selection of a misalignment pattern that results in greater destructive interference between the contributions of the direct current coming from the different stators than what is possible in an optimized implementation of two stators and one rotor.

Constant Maintenance of Terminal Voltage The parallel electrical connections of the stator windings are possible, but ordinarily they are not preferred to practice the present invention. One waveform, for example, waveform 30, generally has a different voltage (higher or lower) than the other waveform 32, at any instant in time. Therefore, there is a high probability that a significant current could flow in a parallel connection from one stator to the other. Such a current is known as a circulating current. Its presence causes energy losses and internal heating. Circulating currents do not provide any useful torque and in some cases can be dangerous for an electrical device. However, the parallel connection of the stator windings is not prohibited according to the present invention. In the preferred embodiments of the invention, the windings of two or more stators are electrically connected in series, and as a result, their electric waveforms are mathematically additive. As illustrated in Figs. 3-9, in which the waveforms 30 and 32 corresponding to two stator windings are connected in series, the resulting voltage at any instant in time (e.g., waveform 34) is the sum of the instantaneous voltages of the two respective waveforms at that instant. As is known in the art, the addition of two exactly sinusoidal curve waveforms, which have the same frequency but different phase, results in another sinusoidal curve of the same frequency, but shifted in phase of the constituent waveforms.

In one aspect, the invention provides the techniques for operating an electrical machine, so that the constant terminal voltage is maintained. An implementation of these techniques is illustrated in terms of an electrical device comprising two stators positioned opposite a single rotor. The graphs of Figures 3 to 9 illustrate the results of the superposition of the waveforms from the two stators, which are misaligned by different amounts of displacement. In the illustration, a stator is taken to be fixed (stator A) w the other is rotating (stator B). In each of Figures 3 through 9, the waveform of the stator A is marked 30, while the waveform coming from the stator B is marked 32. The superposition (addition) of the two waveforms is marked 34. During the operation at constant voltage, the force Electromotive generated is in the intervals with increasing speeds between 100% of base voltage for 0% misalignment of pole separation, and 0% of the base voltage to 100% misalignment of the pole separation. Thus, for convenience, the degree of misalignment is expressed in terms of pole separation for one or more stators. The degree of misalignment is expressed in fractions of a complete pole separation, varying from non-misalignment (Figure 3) to a misalignment of full pole separation (Figure 9). Intermediate values of the misalignment result in the waveforms of Figures 4-8, for electrical misalignments of 30, 60, 90, 120, 150 and 180 °, respectively. Figure 3 illustrates a representative example of the superposition of the substantially identical waveforms 30, 32 for each stator, when there is minimal or no misalignment. Because the relative rotation of the stators is zero, both stators are 100% in phase. The waveforms 30 and 32 of the contribution of each of the two stators are substantially coincident and are constructively added to produce the waveform 34. The electromotive force generated by the machine is therefore also at a maximum, since the waveforms from the stators are added constructively to produce the sinusoidal waveform 34, synchronized, in phase, with maximum amplitude (approximately doubled), indicating the maximum flow contribution of the stators in the rotor position. As the rotating stator (stator B) is rotated out of phase relative to the reference stator, the superposition and the waveforms from the two stators are added to less than the maximum value of Figure 3. In the system of the electrical device, this indicates that the magnetic flux from the two stators in the rotor position is less than the maximum amplitude. As a result, the total electromotive force generated decreases as a function of the degree of misalignment of the stators, resulting in different values of the superposition of the two out-of-phase waveforms. For example, Figure 7 illustrates that to reduce the electromotive force generated at 1/2 of the initial value, the stators must be misaligned by 2/3 of a pole separation phase difference. In this way, the combined synchronous electromotive force is reduced in amplitude to zero as the rotating stator is misaligned in relation to the reference stator, with zero amplitude that occurs when the rotating stator has been misaligned by a full pole separation ( see Figure 9). The waveforms in Figures 3 through 9 are illustrated as pure sinusoidal functions. The superposition of the various periodic waveforms, such as square, trapezoidal, triangular, etc., can be modeled as sinusoidal waveforms. Such waveforms are produced, for example, by electronic energy controllers of the types frequently used in variable speed drive applications. While pure sine waves are preferred, almost pure sinusoidal waves also produce good results. Figure 10 illustrates the result of an overlap of two types of trapezoidal waveforms 35, 36 from two stators connected in series and misaligned by 1/2 full-pole separation. Although, as illustrated, the invention can be practiced with the two trapezoidal waveforms, the resulting triangular waveform 37 is distorted from the original trapezoidal waveforms. Practicing the invention with almost sinusoidal shapes will produce amplitude changes at the output with less distortion in the conformation of the waveform. The use of almost sinusoidal waveforms ordinarily allows simpler electronic energy components to be used, in conjunction with the preferred embodiments of the present machine. As a result of the misalignment, one or more tapped stators can be called "out of phase" with the reference stator. In the above description, the amount of rotational misalignment is defined as a function of pole separation. The degree of rotation of stator B can be directly related to a reduction in the electromotive force generated. However, the reduction is sinusoidally related to the rotation, instead of being linearly proportional. Even so, a direct relation between the separation of the pole and the reduction in the generated electromotive force can be established in the modalities that involve a connection in series.

Ideally, misalignment is achieved with as little rotational movement as possible, while still obtaining the desired reduction in the electromotive force generated. By minimizing the required rotational movement, the design and components (eg, bearings, mating surfaces, rotating devices and the like) used to handle the rotation can be simplified. As discussed hereinabove, low pole count machines with high pole spacing values found in the conventional art are generally not preferred for the practice of this invention. With high pole separation machines, the amount of physical rotation required to achieve sufficient misalignment, even a small reduction in the EMF generated, is sometimes too great to be mechanically practical. The length of the rotation arc of the misalignment for machines with low pole count, is larger and less controllable. As a result, the prior art has ordinarily sought to reduce EMF in axial air gap machines by other means, such as by reducing the length of the air gap (e.g., U.S. Patent Nos. 2,892,144 and 2,824,275) or by reducing of the overlap between the rotor and the stator (U.S. Patent Nos. 403,017 and 6,555,941). However, the implementation of rotational misalignment is much easier in machines with high pole counts, which inherently have a smaller pole spacing. The length of the arc of the rotational misalignment to produce large reductions in the EMF generated, is therefore much smaller in high frequency machines, high pole count, and in conventional machines. The present methods are advantageously applied to electric devices with axial gap, low pole separation, high pole count, high frequency, using advanced magnetic sides, including amorphous and nanocrystalline metals mentioned above, and metals based in iron, oriented in grain and not oriented in grain. The present invention therefore provides a method for reducing the EMF generated without the need to reduce the axial length of the air gap, and reducing the overlap between the rotor and the stator. However, the present method of rotational misalignment is optionally practiced in conjunction with methods involving the reduction of air space, or the change of physical overlap between the rotor and the stator.

Reduction of the Torsor Moment Ripple In some embodiments, the technique of selective alignment of one or more stators with respect to one or more reference stators of the present machine, can also be practiced to reduce the ripple of the torque. A designer of electrical machines preferably attempts to eliminate the variations of the torque to produce a smooth output with substantially constant torque. Desirably, a machine operates with a torque that does not vary with the angular position of the rotor. However, in a given electrical device, there are almost inevitably some rotor positions in which the permeability of the magnetic circuit is higher than for other positions. These are natural positions for the rotor to have an increased torque, for conditions of zero current and applied current. In the technique of dynamo-electric machines, a distinction is often made between the rattle of the torque and the undulation of the torque. The first one refers to the disturbances or variation of the torsional moment with the rotational position without input / output of current to the machine, while the latter refers to the variation of the torque during the operation, for example under load of energy. However, undulation and rattle are physically related phenomena, and are sometimes considered interchangeable. The ripple of the torque is affected by the design of the electrical device and by the operation of the electronic energy components. The rattle of the torsional moment is dependent to a great extent on the parameters of the design of the machine. Since the present invention is primarily related to the design of the electrical device, however, the rattle of the torque and the undulation of the torque can be considered together. The magnets in the rotor provide the largest magnetic flux link to the stator, when a magnet is directly in line with the tooth of a stator. Therefore, in the present machine, when changing the positions of this physical alignment, for example, by rotationally misaligning a stator relative to a reference stator, the angular positions at which the respective stators show their highest flow connections instantaneous, they do not match. For example, stators can be misaligned such that one stator experiences the highest magnetic flux junction in the position at which the other stator shows its minimum flux link. The suitably chosen selective alignment, therefore, substantially reduces the amplitude of the undulation of the torque, although the frequency of the undulation is increased. Regardless of the speed, the ripple of the torque varies from its maximum value (100%) to 0% of slot separation misalignment, and its lowest value to 50% of the slot separation movement. In this way, the degree of misalignment or displacement amounts to reduce the ripple of the torque can be expressed in terms of the slot spacing. The optimum rotational degree of misalignment to minimize the ripple of the torque is to have the rotating stator displaced by exactly 1/2 groove gap relative to the reference stator. Figures 11 and 12 illustrate the perturbations of the torque, at zero electric current, for stators misaligned by 1/2 slot separation (sinusoidal waveform 70), normalized in relation to the disturbances produced when the stators are aligned ( sinusoidal waveform 72). The magnetic flux from the rotor magnets is represented by the sinusoidal waveform 74. While the illustration described in Figures 11 and 12 is for an electrical device with an SPP value of 0.5, the method applies equally well to machines with other values of SPP. With the rotating stator misaligned relative to the reference stator by the amount of 1/2 slot separation, the ripple amplitude of the torque is generally reduced by 1/2, while the ripple frequency of the torque is increased by a factor 2. The natural frequency of the ripple of the torque varies for different values of SPP. For example, the ripple of the torque for an electrical device with an SPP value of 0.5 has a characteristic natural frequency that is 6 times the swing frequency of the electrical device. As previously described, the misalignment of the two stators relative to each other also causes the EMF generated to be reduced. The amount of reduction of the EMF generated for an SPP value of 0.5, is approximately 3.5%, if the stators are misaligned by 1/2 slot separation. A rotation greater than the 1/2 rotation slot separation for the non-reference stator, in fact causes the ripple of the torque to increase again, since the slots become more in line and cause magnetic flux junction every greater time. In the case of 1/2 slot separation rotation, the designer accepts a 3.5% reduction in energy, for a 50% reduction in the ripple of the torque. The ripple behavior of the torque for other proportions of SPP can be similarly determined. Elimination of Torsor Moment Ripples in Multiple Rotor Machines In yet another aspect of the present invention, the selective alignment technique can also be applied to reduce, or preferably eliminate substantially the undulation of the torque and rattle. In embodiments for electrical devices two or more rotors are comprised, the optimum rotational misalignment of the rotors as well as the stators relative to a reference rotor, can result in substantial elimination of the ripple of the torque. While one embodiment of an electrical device comprising a rotor is used for illustration, the techniques of the invention can be practiced in embodiments comprising more than one rotor. For a design comprising two rotors, with the rotors on a common axis, each rotor can be driven by one or more respective stators. There is also some flexibility in the configuration of the stators. For example, in an electrical device with 2 rotors and 4 stators, the stators that are physically closer to each other could be joined in a common stator, giving rise to an effective and efficient machine of 2 rotors and 3 stators.

In such modality, the two rotors are mounted on a common axis. In a conventional design, the two rotors are mounted such that the magnetic poles are aligned circumferentially. However, to practice the selective alignment technique of the present invention for the elimination of the ripple of the torque, the two rotors are misaligned such that one rotor is rotated by 1/2 slot separation relative to the other rotor, while their respective stators are also misaligned to fit the rotors. As a result, the disturbances of the torsion moment are 180 degrees out of phase, and effectively cancel each other out. The technique of selective alignment of the rotors as well as the stators, may not eliminate the contributions of harmonic variations of higher order for the undulation of the torque. In fact, some of these higher harmonics can be constructively increased with misalignment. However, these higher order terms are generally much smaller in magnitude than first order terms, and therefore can be ignored in more electrical device applications. There is also the probability that the ripple waveforms of the torque moment are not perfect sinusoidal waves, and this also results in the superposition that contains some distortion.

Use of Double Full Wave Rectifiers to Reduce Electrical Ripple The ripple is also used in the technique of dynamoelectric machines to refer to certain aspects of alternating current (AC) of the electrical characteristics of a machine. Rectifying means, such as full-wave rectifiers, are used in many prior art power generating devices, and particularly alternators, to take the AC output from multiphase from the windings, and convert it to the relatively soft DC output. . For three-phase applications, this rectification is performed via an array of six diodes conventionally known as a "full wave bridge" or a "diode bridge". Other diode bridge arrays are also known for single-phase and polyphase systems, with others different from three-phase connections. The input to the bridge is the voltage / sinusoidal current generated in the windings; the output is a DC level, known as a DC collective bar. Figure 24 shows a simple graph showing a simple phase, the sinusoidal AC output of amplitude 0.5 (arbitrary units), together with the output of single-phase AC, rectified full-wave, corresponding, and combined three-phase output on the DC collective bar. Although the voltage over the collective bar DC is often considered as a constant (for example, Vdc = Vrmsline * (~ 1.35)), in reality the waveform of the collective bar DC is an overlap of an average DC level but strictly constant , and a smaller AC component. A typical variation of the collective bar voltage DC nominally in a full-wave diode bridge configuration is shown in Figure 24. The AC component, for example, the variation of the average DC level over the collective bar, is known as the electric ripple. Electrical undulation is generally expressed as a percentage (error) of the average DC level. For an ideal three-phase complete wave bridge, this ripple occurs at a frequency that is six times the frequency of any of the original sinusoidal phase voltages. Electric ripple is undesirable for many reasons. These reasons are well known, including the poor characteristics of battery charge in automotive applications, increased harmonic losses in all devices, difficulty in converting the DC level to sine wave voltages free of errors, etc. Therefore, it is desirable to reduce and preferably eliminate the electrical undulation on the collective bar DC. The conventional method for reducing the ripple on the collective bar DC has been to provide one or more capacitors connected in parallel to the DC load. These capacitors act to reduce the amount of ripple to an acceptable level. However, capacitors are expensive and bulky, especially larger capacitors. Therefore, capacitors add cost to the electrical machine and are difficult to place on the machine, especially as size becomes a consideration. In some cases, capacitors also present a reliability problem. Figure 25 schematically shows such a capacitor connected through the DC load in a typical electrical machine of the prior art. This addition of capacitance is known as filtering, since the unwanted undulation is removed, for example, filtered from the pure DC level. Figure 26 shows a typical three-phase rectified rectified voltage produced by the arrangement of Figure 25. A small amount of undulation can be observed on the collective bar DC. Figure 27 shows this ripple in greater detail. Figure 28 shows the average DC energy with the superimposed ripple, typical in association with an electrical machine arrangement such as that shown in Figure 25. Referring now to Figure 29, an electric machine with diode bridges is shown full double wave of the three-phase type, and double stators with three-phase windings. One of the bridges is associated with each respective stator and is connected to the windings of that stator. By contrast, in typical arrangements of the prior art the stator outputs were combined before being connected to a single full-wave bridge. The double full-wave diode bridge array shown in Figure 29 is particularly useful with double stators that are selectively aligned (or "misaligned") such that the stators are rotationally offset with respect to each other as described above. In one embodiment, a stator is physically rotated with respect to the other in a selected alignment that is 30 ° electrically displaced. The outputs of these double diode bridge rectifiers are connected in parallel. The undulation created on the attached DC collective bar has peaks of one bridge that are displaced by the valleys of the other bridge, as a result of the aforementioned 30 ° displacement. Due to the imperfect nature of the sinusoidal shape of the ripple, the reduction of the ripple will not be zero. However, the new combined wave has a waveform nominally with 1/4 of the amplitude and twice the frequency. That is, the peak-to-peak interval in the combined signal is 1/2 of the peak-to-peak range of the constituent waveforms. For an ideal case, the new DC ripple will be about 1/4 of the amplitude of the prior art ripple, and will now occur at twice the ripple frequency of the prior art. Further, as shown in Figure 32, the average DC power of the electric machine array using the double diode bridges completely, and a smaller capacitor, is approximately the same as the prior art array shown with only a full-wave diode bridge (for example, 11 KW for particular simulation shown). Although a double-wave full-diode bridge array, for example the arrangement described in Figure 29, adds cost to an additional diode bridge, it provides substantial savings through the reduced cost of the smaller capacitor, and less space required for the smallest capacitor. In addition, each diode bridge, and the individual diodes thereof, carry only half the current carried in a conventional single bridge, used with a machine of the same energy classification, allowing the use of less expensive diodes. As a further consequence of the increased ripple frequency and the decreased ripple amplitude, a much smaller capacitance is sufficient to reduce the ripple to an acceptable level. As shown in Figure 29, as little as about 1/8 of the previously required capacitance, can be used, and still the ripple on the collective bar DC is approximately the same as that of the typical prior art device having a larger capacitor and only one arrangement of full-wave diode bridge, as shown in Figures 30 and 31. As previously discussed, a physical change in the alignment of the distinctly separate stators results in a change in the resulting EMF, produced from the electric machine. In fact, it has been found that selective alignment of separate stators (eg, a first stator and a second stator) can reduce unwanted DC ripple. In particular, instead of being directly aligned, the first stator and the second stator are selectively aligned to be out of direct alignment by a means of the fundamental frequency (e.g., the synchronous frequency). In physical terms it can be said that this is 1/12 of a magnetic pole pair angle (eg, 1/6 of the pole gap). The explanation of this is that for the most common application (for example, a three-phase machine that works with a full-wave diode bridge), the ripple frequency on the collective DC bus (for example, the output of the diode bridge) is 6 times the frequency of the synchronous frequency of the three-phase machine. In other words, the time interval between the peaks in the ripple frequency is 1/6 of the time interval between peaks of the synchronous frequency. Thus, in order to cancel this ripple frequency as much as possible, the selectively aligned stator must be rotated 1/2 of the ripple time interval, or 1/12 of the synchronous time interval. An additional advantage to the previously described arrangement of selectively aligned stators, with double-full-wave rectifiers, is that the size and cost of the capacitor used through the DC load is directly related to the amplitude of the ripple, and to the inverse of the frequency of the ripple. Thus, this invention has an advantage in reducing the size and cost of the capacitor, which can be used through the DC load compared to the capacitors in the prior art solutions. Typically, a capacitor of 1/8 the size of the capacitor that could have been required under the prior art arrangement, is all that is required. In some applications, the ripple may even be low enough that no capacitance is necessary. Mechanisms for the Rotational Misalignment of the Stators The present machine can be implemented with the stators that are placed with either a fixed or adjustable degree of relative displacement. In modes with adjustable displacement, a misalignment means of any suitable type allows adjustment between a minimum and a maximum displacement amount. Preferably, the displacement is adjustable between the substantially complete alignment of the corresponding teeth and the grooves of each stator and the misalignment by up to one half of the slot separation or the complete pole separation. Modes with either manual or automatically adaptive adjustment are within the scope of the present invention. A number of misalignment means are suitable, including those used in the three different kinds of systems discussed hereinafter, each having different input parameters. The first system involves the active control of the EMF through the movement control of a rotating stator via an external source. The second system involves control via a speed-dependent mechanism. The third system involves control via a mechanism dependent on the torsion moment. Any of the three systems described or other similar systems can be practiced in a simple manner or in a given electrical device, or in any combination. While the systems are described in connection with the reduction of the EMF generated, a person of ordinary skill in the art could employ any of the above systems to reduce or substantially eliminate the ripple of the torque according to the above teachings.

External Control The controlled selective alignment technique of one or more stators in relation to one or more reference stators can be achieved through the use of an external control source to control the value of the EMF generated. In preferred embodiments, the external control source has a power source that is independent of the electrical device being controlled. Through the choice of the appropriate position of the rotating stator, the desired EMF can be achieved. Many different means to achieve proper positioning are available in the art. In some embodiments, the misalignment of the stator is adjustable in two or more discrete steps of misalignment, one of which may be substantially substantially complete alignment. Other embodiments contemplate a continuously variable misalignment in the range from a minimum to a maximum displacement. The misalignment must be driven by any suitable source of mechanical movement, including pneumatic, hydraulic, piezoelectric, electric or magnetic actuators, or the like. The misalignment means comprises appropriate positioning devices, which may include not exclusively any one or more of a two-position solenoid; a voice coil motor; a piezoelectric actuator; a stepper motor or other motor with a gear, guide screw, or the like; a vacuum cylinder; an air pressure cylinder; a hydraulic cylinder; and a linear motor. The gradual speed motor with guide ignition is preferred for its reliability, mechanical stability, and ease of implementation and precise control. In addition, an elastically deformable return member, such as a spring, may be provided. Alternatively, some or all of the misalignment can be manually triggered. Figure 13 illustrates a top view and a side view of one embodiment of an electrical device comprising a single rotor 40 and two stators 42, 44. One stator is taken as a fixed reference stator 44, while the other stator is a stator. rotary stator 42. A stator alignment control 46 is connected to the reference stator 44. An external control system 48 provides the means for rotating the rotary stator 42 from the zero misalignment position to the desired degree of misalignment. Figures 14 and 15 illustrate two different positions of the external control system 48 for controlling the misalignment of the rotating stator 42. The position of the external control system 48 could be correlated with the desired degree of misalignment to produce, for example, the desired reduction in the EMF generated. In one embodiment, a solenoid is coupled to the rotating stator. This solenoid positions the rotating stator to achieve the desired EMF generated. A control signal comes from the demand for the generated EMF. The solenoid positions the rotatable stator in one of two rotation positions, as required. It is also possible, and especially preferred, to position the stator using a motor and guide screw assembly. This provides a number of positions larger than a simpler two-position solenoid. It is also possible to place the rotating stator with any combination of electrical, pneumatic, hydraulic, piezoelectric or other mechanical devices. In machines incorporating any of the aforementioned means, one or more counterweights (not shown) are optionally provided to compensate for any problematic imbalance of the stators, caused by the mass of the positioning mounts.

Speed Dependent Control A mode that involves a speed dependent control of rotational misalignment does not require general feedback from the machine's EMF. Rather, the generated EMF is designed to be in a range that can be controlled by a speed-dependent device. A speed dependent device is one that causes the rotating stator to move from a base position (generally approximately zero misalignment) to the desired degree of misalignment as the speed increases. The rotational speed of misalignment of one or more rotating stators, is prescribed according to the desired rate or rate of reduction of the EMF generated. The misalignment is reversible. That is, as the speed decreases, the misalignment of one plus rotating stators decreases, returning to the base position of zero misalignment at a specified minimum speed (which may be zero). One embodiment of a machine that incorporates speed-dependent control is described by Figures 16 through 18, which illustrate the operation of a speed-dependent control, mechanical governor style for rotational misalignment in a mode of an electrical device. , which comprises a simple rotor 40 and two stators 42, 44. The centrifugal assembly 55 comprises the weights 50, which are connected to a flange which is mounted to the rotary shaft 52. The weights 50 are allowed to oscillate at a further radial working distance. large (from the center of the rotation) as the speed increases. The centrifugal assembly also comprises a spring system for returning the weights 50 to the radial radial working distance retracted at very low speeds. In the illustration of Figures 16 to 18, the weights 50 also have rounded triangular cams that interact with a cup 54. As the speed increases during operation, the centrifugal forces provide more and more force to overcome the spring force that it acts on the 50 weights, and causes them to oscillate at the ever increasing radial distance (Figure 18). As a result, the rounded triangular cams cause the cup 54 to move to the right in the illustration, for example, to be pressed towards the stationary stator 44. The cup 54 rests on a thrust bearing 56, which is coupled to a screw 58 low separation, which is connected to the rotating stator 42. The depression of the cup results in the end the misalignment rotation of the rotating stator 42 relative to the fixed stator 44. The low-clearance screw 58 moves on straight tabs on its internal diameter. The low-clearance screw 58 is constrained not to rotate, since it is held by the axially parallel internal tabs. As the low-clearance screw 58 is moved axially, it in turn rotates the rotating stator 42 to the desired angular position. These straight tabs are at the end coupled to the reference stator 44 by means of support rays. At low speeds, and thus at lower centrifugal force, the weights are retracted by the spring force at their smallest radial working distance, as illustrated in Figures 16 and 17. As a result, the cup 54 and the screw 58 of low separation move to the left of the drawing. Since the low-clearance screw 58 is constrained to rotate on its own, it forces the rotating stator 42 to rotate. To achieve this, the rotating stator 42 needs a bearing system capable of a small degree of rotation. The exact design of the rotation system, including the selection of features such as screw clearance, screw length, weight mass, weight length, cam and cup design, etc., for a system of given machine, it is optimized to provide the desired change in the EMF. All these parameters can be selected or optimized as a function of the degree of rotation of pole separation. Dependent Control of the Torque Moment The modalities that involve the torque-dependent control of the rotational misalignment, can provide either torque control only or torque speed. A mode that involves control only of the torque generated by the EMF is based on the principle that at a constant speed, as the current increases, the power or energy increases. Since energy = velocity x torsional moment, as the energy increases for a constant velocity, then the torsional moment must also increase. If the rotating stator is mounted on variable points, then it can rotate in the direction of the torque from the rotor. This rotation changes the EMF generated, and thus the demand for current. In this embodiment of the invention, the amount of rotational deflection is a function of the current demand. A mode that involves control dependent on the torque of the speed is such that, as the energy output of the electrical device is increased, the speed of the rotor axis is also increased. The proportion of the increase in speed should not be as great as the proportion of the increase in energy. Since energy = speed x torque, the torque on the machine must also increase. The increase of the torque is used to position the rotating stator, and therefore to control the generated EMF.

Regardless of whether the electrical device is allowed to change speed, the rotating stator 42 may be connected to the reference stator by one or more variable points. At the variable points in the stator alignment control 46 shown in Figures 19 through 22, there is an elastic material or device mounted between the variable point and the rotating stator 42. In Figures 19 to 22 only a variable point and only a stator alignment control 46 is shown for demonstration ease. However, in different embodiments there may be more than one control 46 of stator alignment or variable point. In the embodiment of Figures 19 and 20, the rotating stator 42 is mounted on one or more elastically deformable members, such as the springs 47. The springs 47 allow the rotating stator 42 to move through a limited angle of rotation with the changing torque The springs could preferably be compression springs. However, other options that are easily applicable include tension springs, coil springs, sheet springs, etc. A variation on springs 47 could be rubber or another organic assembly. In the embodiment of Figures 21 and 22, the rotating stator 42 is mounted on a shaping material 49. The forming material 49 could preferably be some form of urethane. However, other options for the shaping material include, but are not limited to, rubber, latex, silicone, oil-filled shocks, air pressure, or the like.

Machine System and Electronic Power Control In yet another aspect, a dynamo-electric machine system comprising an axial electric air gap machine, and electronic energy means for interconnecting and controlling the machine is provided. The system can contain as a motor or generator or a combination thereof. The motor machines must be supplied with AC power, either directly or by DC power switching. Although mechanical switching with brush-type machines have been used for a long time, the availability of high-energy semiconductor devices has made possible the design of brushless electronic switching means, which are used with many modern permanent magnet motors. In generation mode, a machine (unless mechanically switched) inherently produces AC. It is said that a large proportion of machines operate synchronously, which is why it is understood that the AC input or output energy has a frequency commensurate with the rotational frequency and the number of poles. Synchronous motors connected directly to an energy grid, for example, the 50 or 60 Hz grid commonly used by electrical installations or the 400 Hz grid frequently used in on-board and aerospace systems, therefore operate at particular speeds, with variations obtainable only when changing the pole account. For synchronous generation, the rotational frequency of the main motor must be controlled to provide a stable frequency. In some cases, the main motor inherently produces a rotational frequency that is too high or too low to be accommodated by motors that have pole counts within practical limits for the design of known machines. In such cases, the rotation machine can not be connected directly to a mechanical axis, so a gearbox must be used frequently, despite the expected aggregate complexity and loss in efficiency. For example, wind turbines rotate so slowly that an excessively large pole count would be required in a conventional engine. On the other hand, to obtain the proper operation with the desired mechanical efficiency, typical gas turbine engines rotate so rapidly that even with a low pole source, the frequency generated is unacceptably high. The alternative for motion and generation applications is the conversion of active energy. The embodiments of the present electric machine that includes misalignment means for back electromotive force control are beneficially employed with the conversion of active energy, especially in applications involving a wide range of speeds and / or energy requirements triggered. As used herein, the term "electronic energy components" is understood to mean a set of electronic circuits adapted to convert the electrical energy supplied as direct current (DC) or as alternating current (AC) of a particular frequency and a particular waveform, to electric power sent from DC or AC output, the output and the input differ by at least one of the voltage, frequency and waveform. The conversion is achieved by a set of electronic energy conversion circuits. For a different transformation from the simple voltage, AC power using an ordinary transformer that preserves the frequency and the simple bridge rectification of AC to provide DC, the modern conversion of energy usually employs non-linear semiconductor devices and other associated components that they provide active control. As discussed hereinabove in greater detail, machines constructed in accordance with the present invention are operable as motors or generators over a wider range of rotational speeds than conventional devices. In many cases, the gearboxes required to date in motor and generator applications can be eliminated. However, the resulting benefits also require the use of operable electronic components over a wider frequency range than those used with conventional machines. For applications in dynamo-electric machine system motors, the machine is interconnected to an electrical source, such as the electric power grid, the electrochemical batteries, fuel cells, solar cells or any other suitable source of electrical energy. A mechanical load of any required type can be connected to the machine shaft. In the generation mode, the machine shaft is mechanically connected to a main motor or mover and the system is connected to an electrical load, which can include the form of an electrical appliance or a store of electrical energy. The machine system can also be used as the regenerative motor system, for example as a system connected to the drive wheels of a vehicle, alternatively providing mechanical propulsion to the vehicle and converting the vehicle's kinetic energy back into electrical energy stored in a vehicle. battery to effect braking. The electronic energy means useful in the present axial air gap machine system, should ordinarily include active control with sufficient dynamic range to accommodate the expected variations in mechanical and electrical loading, while maintaining satisfactory electrochemical operation, regulation and the control . Any form of energy conversion topology can be used, including interruption or switching regulators that employ shake and reverse thrust converters and pulse width modulation. Preferably the voltage and current are independently controllable in phase, and the control of the electronic power components can operate with or without direct detection of the position of the shaft. In addition, it is preferred that four quadrant control be provided, allowing the machine to operate for clockwise or counter clockwise rotation in either the motor or generator mode. The current loop and the speed loop control circuitry is preferably included, whereby control can also be employed in the torque mode and control in the speed mode. For stable operation, the electronic energy means should preferably have a control loop frequency range at least about 10 times as large as the intended switching frequency. For the present system, the operation of the rotating machine of up to about 2 kHz switching frequency, thus requires a control loop frequency range of at least about 20 kHz. The controllers used in motor operations typically employ IGBT semiconductor switching elements. These devices show an increase in interruption or switching losses, often, so that it is ordinarily preferred to operate with switching frequencies of up to about 1000 Hz. The motor systems are thus advantageously designed with switching frequency in the range of 600 to 1000 Hz, allowing the use of less expensive IGBTs while retaining the benefits (e.g., increase in energy density) resulting from the Higher operating frequencies made possible by low loss materials. For generation applications, suitable rectifier bridges allow operation even at higher switching frequencies. In some preferred embodiments, the machine comprises the misalignment means driven by an externally imposed electrical signal, and the electronic power means further comprises the circuitry to provide a signal suitable for driving the misalignment means. Beneficially, the use of the means to control the counter electromotive force allows the complexity and the electrical classifications of the electronic means of energy to be reduced, which simplifies the manufacture and reduces the costs of the electronic means of energy. In particular, the misalignment can be selectively introduced during periods of high speed operation to limit the voltages that must be handled by the electronic means of energy. Preferably, the misalignment is controlled using a signal transmitted from the power means to the misalignment means. It is also preferred that the adjustment of the displacement amount be adaptive. That is, the quantity is adjusted commensurately with the speed of the machine. For example, the increase can be in proportion to the speed. The following examples are provided to more fully describe the present invention. The techniques, conditions, materials, proportions and specific reported data, described to illustrate the principles and practice of the invention are exemplary and should not be considered as limiting the scope of the invention.

Examples Variable Speed Generator In a generator, the torque is always in a constant direction, for example, resisting the rotation of the mover or main motor. The main engine is any device, for example, a gasoline or diesel engine, a turbine, a water wheel, or a similar source of rotational mechanical energy, which drives the generator. At low speed, the main motor typically has low energy, and the ability of the generator to distribute electrical power is therefore low. Main engines ordinarily produce more energy at higher speeds, and thus the generator must be designed to produce more energy at higher speeds. Ideally, the output of the generator should be adjusted to the output of the main motor at all speeds. Improvements in power semiconductors allow electronic power converters to receive large amounts of energy at a frequency range and efficiently and cheaply distribute the output power, either to DC or as a waveform synthesized at another frequency. Consequently, designers can optimize their designs to accommodate main engines operating at higher or variable speeds, rather than being limited to sources that rotate at a fixed speed coupled with a required output frequency, or that have to include a speed adjustment device such as a gearbox. It is also desired that at all speeds the output voltage be constant. These characteristics allow a much simpler and less expensive electronic energy control strategy. Therefore, for situations of variable speed and variable energy, the most desirable situation is that only the output current must change, or change minimally. If the rotating stator is mounted on variable points, the rotating stator is allowed to move a limited amount as a function of the applied torque. When the rotating stator is at rest in a position of zero misalignment, this produces the maximum generated EMF. The main engine speed profile, preferred, is to operate the main motor at high speed for high energy and low speed for low energy. At low speed, the energy is low and the current is low. The torque is a function of the generated output energy, divided by the speed, and therefore the torque is also low. Therefore, the speed of the main motor is typically increased to produce more power and current and torque. The increase of the torsional moment causes the rotating stator to move to a certain extent, the extension being determined by the spring force. By itself, the rotating stator causes the generated EMF to decrease, but simultaneously the increased speed increases the EMF generated. These at least partially displaced increases and decreases are carefully designed by the machine designer to produce the substantially constant, desired output assembly. Pious consideration should be given to: the spring force, the EMF generated at minimum misalignment, the nonlinear reduction of the EMF with the degree of rotation, the linear increase in the EMF generated due to the speed, and the complete electrical circuit, and the resulting phasor diagram allows a person of ordinary skill in the art to design a machine to produce the desired, constant voltage output. It is also possible to allow the torque produced on the stator to supply the force to move the stator. Figure 23 shows a graph of the parameters of the generator during the operation according to this embodiment of the invention. As the output energy of the generator increases, so does the current. The torque of the motor increases along with the increase in power output and current. The torque of the rotor, increasing, acting on the stators, eventually exceeds the voltage supplied by the springs coupled to the rotating stator, which causes the rotating stator to rotate. The rotation of the rotating stator causes the EMF generated to fall, limiting the voltage. Therefore, in this embodiment of the invention, the rotor produces a quantity of torque directly as a function of the current flowing in the coils in both stators. In this way, the invention provides a self-regulating machine that provides almost constant voltage. Although the present invention has been described above in further full detail, it will be understood that such detail should not be strictly followed to the letter, but that additional changes and modifications may be suggested to themselves by a person skilled in the art. For example, stators can be displaced by any number of different angles to provide different results. It is therefore intended that such modifications be encompassed by the scope of the invention, as defined by the appended claims. It is noted that in relation to this date, the best known method for carrying out the aforementioned invention is that which is clear from the present description of the invention.

Claims (20)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. An axial air gap electric machine, characterized in that it comprises: (a) a first stator having a plurality of teeth and a first group of windings placed thereon; (b) a second stator having a plurality of teeth and a second winding group placed thereon, the second stator is selectively aligned with respect to the first stator, such that the teeth of the second stator are displaced from the teeth of the first stator; and (c) a rotor positioned axially between the stators and supported for rotation about an axis, and wherein the stators comprise toroidal cores having laminated plates composed of a material selected from the group consisting of amorphous and nanocrystalline metals and an alloy Iron-based, optimized.

The axial air gap machine according to claim 1, characterized in that it further comprises: (d) a first complete wave diode bridge connected to the first winding group; and (e) a second full-wave diode bridge connected to the second group of windings.

3. The axial air gap machine according to claim 1, characterized in that the displacement between the first stator and the second stator is 1/12 of the fundamental frequency of the axial air gap machine.

4. The axial air gap machine according to claim 1, characterized in that it also comprises misalignment means for adjusting the displacement of the stators.

The axial air gap machine according to claim 3, characterized in that the displacement is adjustable by an amount of displacement in the substantially complete range of alignment up to misalignment, by an amount of displacement of one half of the separation of the slot and a full pole separation.

6. The axial air gap machine according to claim 3, characterized in that the misalignment means comprises at least one of a two-position solenoid; a voice coil motor; a piezoelectric actuator; a gradual motion motor or other motor with a gear or guide screw; a vacuum cylinder; an air pressure cylinder; a hydraulic cylinder and a linear motor.

7. The axial air gap machine according to claim 5, characterized in that the misalignment means comprises a stepper motor and the guide screw.

8. The air gap machine according to claim 1, characterized in that the laminated layers are composed of amorphous metal.

9. The axial air gap machine according to claim 1, characterized in that the rotor comprises a plurality of rotor magnets composed of a rare earth-transition metal alloy.

10. The axial air gap machine according to claim 1, characterized in that the ratio of groove per phase per pole is in the range of approximately 0.25 to 1.

11. The axial air gap machine according to claim 10, characterized in that the ratio of slot per phase per pole is 0.50.

12. The axial air gap machine according to claim 1, characterized in that it has at least 16 poles.

13. The axial air gap machine according to claim 1, characterized in that it is adapted to run with a switching frequency in the range of approximately 500 Hz to 3 kHz.

14. The axial air gap machine according to claim 1, characterized in that it also comprises electronic energy means for interconnecting and controlling the machine and for being operably connected to it.

A method for operating an axial air gap machine, characterized in that it comprises: (a) the provision of an electric axial air gap machine, comprising a first stator having a plurality of teeth and a first group of windings placed on it; a second stator having a plurality of teeth and a second group of windings placed thereon; and a rotor positioned for rotation about an axis, the rotor is placed axially between the stators, and wherein the stators comprise toroidal cores having laminated layers composed of a material selected from the group consisting of amorphous and nanocrystalline metals and optimized alloy based on iron; and (b) selectively aligning the second stator with respect to the first stator, such that the teeth of the second stator are displaced by an amount of displacement of the teeth of the first stator.

16. The method according to claim 15, characterized in that the displacement amount is selected to reduce the undulation of the machine torque.

17. The method of compliance with the claim 15, characterized in that the machine further comprises the misalignment means for adjusting the displacement of the stators by an amount in the range from a minimum displacement to a maximum displacement, and the method further comprises adjusting the amount of displacement using the misalignment means.

18. The method of compliance with the claim 17, characterized in that the amount of displacement is adjusted to maintain a substantially constant voltage characteristic.

19. The method according to the claim 18, characterized in that it further comprises adaptively controlling the adjustment of the displacement amount using a signal transmitted from the electronic energy means to the misalignment means.

20. The axial air gap machine according to claim 1, characterized in that it comprises a plurality of at least three stators, each of the stators has a plurality of teeth and a group of windings placed on them, the stators are placed coaxially around of the shaft and a plurality of rotors, the rotors being supported for rotation about the axis, and each of the rotors is positioned between the axially adjacent ones of the stators, and the axially adjacent ones of the stators are selectively aligned such that the the axially adjacent of the stators are displaced from each other.