Electrical machinery

Abstract

AC electric machines have capacitive windings or connections, represented in circuit diagrams by capacitors, such as wire wound into electromagnetic coils, capacitively coupled and separated by a dielectric, which replace traditional coils in machines such as motors, generators, transformers, coils, and antennas.

Description

[Technical Field]

[0001] The present invention relates to electric machines, in particular to electric machines comprising one or more windings. [Background technology]

[0002] The terms "electric machine" and "motor" are commonly used to refer to machines that use electromagnetic power, such as electric motors, generators, and transformers. They can convert electromagnetic energy into mechanical energy, vice versa, or transmit magnetic energy from one winding to another separated by electrical or galvanic isolation. For example, electric motors convert electricity into mechanical power, and generators convert mechanical power into electricity. Another example is a transformer, which converts alternating current voltage levels. Developing more efficient electric machines has uses and benefits in many electromagnetic applications.

[0003] No. 7,154,364 discloses an electric machine with high voltage windings that use conventional electrical wire. Other known machines have similar electrical windings of various shapes and configurations. Summary of the Invention [Problem to be solved by the invention]

[0004] It is an object of the present invention to provide alternative electric machines having different wiring and / or winding arrangements, and an object of certain embodiments to provide improved electric machines, for example, electric machines that may be smaller and / or lighter. [Means for solving the problem]

[0005] According to the invention, there is provided an electric machine comprising a capacitive winding (or capacitive connection), which may for example be two or more windings that are capacitively connected.

[0006] The present invention also provides an electric machine comprising a conductor wound in the form of an electromagnetic coil, the conductor being a capacitive conductor represented by a capacitor in a circuit diagram.

[0007] The present invention further provides an electric machine having a capacitive winding which is a coiled capacitive wire, the capacitive wire being any wire having capacitive coupling within the conductor / conductor element of the wire and represented by a capacitor in a circuit diagram.

[0008] There is also provided a method of manufacturing a machine of the invention, for example as described above, comprising: Providing a capacitive conductor (e.g., a wire, cable, or conductor); and · Forming or fabricating this capacitive conductor into a winding.

[0009] The use of capacitive connections to the windings of electric machines offers new machines and new machine options with significant potential advantages.

[0010] To facilitate an understanding of the invention, embodiments thereof are described above and below by way of example with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of an induction motor with a delta-connected capacitive winding according to the present invention. [Figure 2] FIG. 2 is a schematic diagram of an induction motor with star-connected capacitive windings according to the present invention. [Figure 3] FIG. 3 illustrates in generalized form the circuit diagram of the capacitive winding of the present invention. [Figure 4] FIG. 4 is a schematic diagram of a first transformer of the present invention. [Figure 5] FIG. 5 is a schematic diagram of a second transformer of the present invention. [Figure 6] FIG. 6 is a schematic diagram of a third transformer of the present invention. [Figure 7] FIG. 7 is a schematic diagram of a conventional transformer (not part of the present invention). [Figure 8] FIG. 8 shows the operational performance of the transformer of FIG. [Figure 9] FIG. 9 shows a schematic diagram of a transformer of the present invention designed to replace the transformer of FIG. [Figure 10] FIG. 10 shows the operational performance of the transformer of FIG. [Figure 11] FIG. 11 shows the transformer of the present invention (left) and a conventional transformer (right) with equivalent performance, and indicates their respective sizes. [Figure 12] FIG. 12 shows the increase in dielectric strength as a function of voltage for selected dielectric materials. [Figure 13] FIG. 13 shows the relationship between applied voltage and required capacitance for selected dielectric materials. [Figure 14] FIG. 14 shows a circuit diagram of an induction motor with conventional windings (not part of the present invention). [Figure 15] FIG. 15 shows a circuit diagram of an electric machine of the invention with a capacitive winding. [Figure 16] FIG. 16 shows a circuit diagram of an electric machine of the invention with a capacitive winding. [Figure 17] FIG. 17 shows a circuit diagram of an electric vehicle charge plate incorporating the capacitive coil of the present invention. [Figure 18] FIG. 18 shows a circuit diagram of a transformer of the present invention that uses high frequency CTS cables as both the feed cable and the windings. DETAILED DESCRIPTION OF THE INVENTION

[0012] The electric machine of an embodiment of the present invention comprises a capacitive winding, preferably a capacitive connection (e.g. a winding or coil) that is represented in a circuit diagram by a capacitor.

[0013] The electric machine of the present invention comprises a conductor wound into an electromagnetic coil, which is a capacitive conductor represented by a capacitor in a circuit diagram.

[0014] An electric machine may comprise a capacitive winding, which is a coiled piece of capacitive wire, any wire that has capacitive coupling within the conductor / conductor element of the wire and is represented in a circuit diagram by a capacitor.

[0015] Typically, as shown in more detail in the examples below, a capacitive conductor, capacitive wire, or capacitive winding includes two conductors coupled together through a capacitive coupling. The two conductors may be electrically separated from each other by a dielectric material, or the dielectric material and the conductors may together form the capacitive coupling.

[0016] In use of the present invention, machines with capacitive windings operate using alternating current (AC) and provide an alternative or replacement for known machines with conventional conductors in the windings.

[0017] A conductor may include a wire and / or a cable (e.g., typically with an electrical insulator, sheath, or insulation). Thus, a conductor may include a wire, a plate, graphene, a metal (e.g., aluminum or copper), a ferromagnetic material, or a trace or line on a PCB. A conductor, as used in the examples below, is typically an insulated wire.

[0018] Here, the term "winding" is used in the conventional sense to refer to one or more turns of wire or cable (more generally, a conductor) forming a continuous coil, such as an electromagnetic coil. A winding is an electrical conductor formed or wound in a coiled, spiral, or helical shape. Electromagnetic windings and / or coils are used in electric machines such as electric motors, generators, inductors, electromagnets, transformers, chargers, wireless chargers, and sensor coils. A magnetic field may be generated by passing an alternating current through the coil, or conversely, an external, time-varying magnetic field may be passed through the coil to generate an electromagnetic force (EMF) or voltage in the conductor. The coil or winding may be wound around a coil former. The coil or winding may further include a core, preferably a ferromagnetic or ferrimagnetic material, such as iron, to guide and increase the magnetic field generated during use.

[0019] While the term is conventional, a "capacitive wire" herein refers to any wire or cable that has capacitive coupling within its conductors / conductive elements. Similarly, a "capacitive conductor" herein refers to any conductor that has capacitive coupling within its conductors / conductive elements. The term "capacitive" does not refer to the cable capacitance characteristics of conventional conductors, such as conventional power transmission lines. Nor does it refer to the capacitance between two insulated conductors within a conventional power transmission line. Instead, the term "capacitive" refers to a wire, cable, or conductor that is part of a capacitive transmission system and is represented by a capacitor in a circuit diagram. Examples include WO2010 / 026380, WO2019 / 234449, WO2021 / 094783, WO2021 / 094782, and WO2020 / 120932. In these documents, capacitive wires are sometimes referred to as capacitive transmission system (CTS) connections or CTS cables. Thus, embodiments of the present invention use CTS connections, CTS cables, or conductors wound in a "capacitive winding" and used in one or more windings in an electric machine. In one application, the capacitive nature of the CTS connection may control the current in the coils of an AC machine, as described further below.

[0020] The capacitive winding may include a conductor and / or there may be capacitive coupling within the conductor, and preferably the conductor of the capacitive winding includes two or more conductors appropriately coupled to each other via capacitive coupling.

[0021] Alternatively, or in addition, the conductor may include two conductors, such as wires, which may be electrically separated from each other, for example, by any dielectric and / or insulating medium (or insulator), which may be air in some embodiments. The dielectric material and the wire together then form a capacitive coupling. Preferably, the capacitive winding includes a conductor, which may be coiled, spiral, helical, or any other suitable geometric shape.

[0022] Thus, as one example of the present invention, a winding of an electric machine includes two capacitive wires (a first wire and a second wire) that are electrically insulated from each other by a dielectric and thus form a capacitive coupling, with an end of the first wire connectable to a positive power supply side and an end of the second wire connectable to a negative power supply side, and these two wires are wound into a coil or winding and used as a replacement or substitute for a conventional winding or coil (see, for example, Figure 3 of the drawings which generally shows such a winding).

[0023] A corresponding method of the invention for manufacturing a machine comprises: providing a conductor comprising two or more conductors (e.g., wires) separated by a dielectric or insulating medium and forming a capacitive coupling between the two conductors; and The process of winding, making, or forming a conductor into a coil Includes.

[0024] In one embodiment of the present invention, a capacitive cable including twisted first and second wires is wound into a coil, with the proximal end of the first wire connected (or ready to be connected) to the positive terminal of a power source and the distal end of the second wire connected (or ready to be connected) to the negative terminal of the power source, in one example having approximately 100 turns. This forms the primary coil of a transformer. The secondary coil of the transformer can be conventional or can be made using capacitive cable. If the primary coil is conventional as defined herein, the secondary coil is capacitive (as defined herein).

[0025] Preferably, each or all of the capacitive windings have capacitive reactance. The electric machine may preferably include both inductive and capacitive elements. The capacitive windings may generate both magnetic and / or electric fields. Alternatively, the capacitive windings may transmit energy using magnetic and / or electric fields.

[0026] Electric machines with windings are widespread. The present invention replaces conventional windings with capacitive windings. Therefore, it is believed that the present invention has a wide range of applications. The electric machine is preferably a transformer, a motor, a generator, a solenoid, an electromagnet, an antenna, a filter (such as a HiFi), a furnace, a heater, a charger, a wireless power transmission system (e.g., a wireless charger), and / or a dynamo. If the electric machine is a filter, the machine (or the windings) may have resistance, inductance, and capacitance. The transformer or AC machine may be coreless, such as a wireless energy transformer, a coreless transformer, or a coreless motor.

[0027] In certain embodiments, the electric machine is a transformer. The transformer may further include a capacitor connected to the primary coil and / or integrated with the primary coil. Preferably, there is no galvanic connection between the coil and the ferromagnetic core. The transformer may be a step-up transformer, a step-down transformer, or an isolation transformer.

[0028] In particular embodiments, the electric machine is a motor or a generator. The motor may be an induction motor, and specific embodiments of the invention are exemplified below in the form of a motor.

[0029] In certain embodiments, the electric machine is a wireless pad, e.g., a charging pad, which may also be referred to as a grounding pad or a transmitting pad. In use, the charging pad interacts with another wireless pad, which may be referred to as a vehicle pad or a receiving pad, to wirelessly transmit power. Either or both pads may include a capacitive winding of the present invention. One preferred application is charging electric vehicles. The present invention provides a wireless charging station including a capacitive winding of the present invention and / or an electric vehicle including a capacitive winding of the present invention.

[0030] Other applications include charging mobile phones, smartphones, and other portable electrical devices. The present invention provides a charging station for a portable electrical device comprising the capacitive winding of the present invention. The present invention also provides a mobile phone or other portable electrical device comprising the capacitive winding of the present invention.

[0031] The electric machine of the present invention may optionally include a secondary capacitive coil or winding connected to a capacitor. In the examples below, both the primary and secondary transformer windings are capacitive windings. In some embodiments, the primary coil is connected in series with the capacitor and / or the secondary coil is connected in parallel with the capacitor.

[0032] The number of turns of the windings of the present invention will vary depending on the intended winding characteristics and application. Like conventional windings, windings of the present invention generally contain at least 5 turns, at least 20 turns, or at least 50 turns. Additional windings of the present invention contain at least 100 turns, at least 300 turns, at least 500 turns, and even more turns.

[0033] It has been found that the present invention can be used to make and use electric machines that are smaller and lighter than known machines, yet have the same or better performance. As a specific example, described in more detail below, transformers have been made using the capacitive windings of the present invention and have been found to perform equivalently to transformers about twice the size and weight made using conventional windings.

[0034] This means that the electric machine of the present invention may also be advantageous in situations where weight and / or space are an issue, or in certain situations such as, for example, in the aviation industry, and in particular for electric machines on or in aircraft, which is independent of the frequency used, with the weight reduction likely to apply to low frequencies (for example around 50 Hz) and high frequencies in use.

[0035] In general, the machine of the present invention can operate over a wide range of AC frequencies. Embodiments of the present invention operate using high frequency AC, for example, above 350 Hz, or above 400 Hz, and alternatively up to 2.8 MHz. In these embodiments, cables are suitably used, each cable being (a) a first plurality of conductors for connecting to a power source; (b) a second plurality of conductors for connection to a load; and (c) a dielectric material between the first plurality of conductors and the second plurality of conductors. Including, Each conductor is individually insulated, At least one conductor of the first plurality of conductors and at least one conductor of the second plurality of conductors are woven or wound into one or more bundles, with each individual conductor repeatedly transitioning between the outside of one or more bundles and the inside of one or more bundles along the length of the one or more bundles.

[0036] In such high frequency embodiments of the invention, the electric machine is suitably constructed using the cables described in co-pending European Patent Applications Nos. 22209216.5 and 23175297.3. In a preferred embodiment, the electric machine is constructed using Litz wire.

[0037] In conventional electric machines, excessive current flowing through the windings can cause the wires to burn out. Conventional transformers have solved this problem by increasing the number of turns in the windings. However, this increases both the size and weight of the transformer. In contrast, the electric machine of the present invention allows for an increase in the number of turns without the drawbacks. Therefore, instead of increasing the number of turns to increase the reactance, an increase in reactance can be achieved by adding an additional capacitor or by changing the capacitance of that capacitor. This is particularly true when capacitive wire is used. As a result, it may not be necessary to increase the number of turns in the primary coil to increase the voltage across it, which means that a smaller core can be used.

[0038] In some embodiments, the capacitive winding alone may not provide enough capacitance. One or more additional capacitors can compensate for this. However, these capacitors should be considered part of the capacitive wire (or cable) and are not typically considered to be connected in series or parallel. Instead, they are best considered to form part of the CTS connection.

[0039] In certain embodiments, the use of capacitive wire (or cable) can mean that the voltage ratio of a machine winding is no longer dependent on the ratio of the winding's turns. Instead, the capacitance ratio of the two coils can be used to determine the voltage ratio. So, for example, in a transformer, it is advantageous for the primary winding to have the same number of turns as the secondary winding, but the capacitance ratio between the two windings can determine whether the transformer is a step-up or step-down transformer.

[0040] In an embodiment of the invention, for example a transformer, an electric machine includes two or more capacitive windings and a capacitance control that varies the capacitance ratio between the two or more capacitive windings.

[0041] Machines can also include dynamic configurations: for example, if the capacitance of the circuits on either side of a transformer can be adjusted, the power profile (e.g., voltage on both windings) can also be adjusted (often without having to change the number of turns on either winding).

[0042] In an embodiment of the invention, the electric machine comprises a capacitive power transmission wire comprising: At least two sets of conductive strands distributed within the cross section of the winding and in a capacitive relationship with each other wherein all strands of at least one set have: ·Insulating coatings on each of the sets of conductive strands with dielectric strength that keep them separated from each other.

[0043] In these embodiments, at least a portion of the power transmission wire is in the form of a winding.

[0044] The conductors or strands typically comprise copper and / or other conductive material. Typically, there are two or more sets of strands in a winding, which preferably alternate within a layer.

[0045] One set of conductive strands may be uninsulated, for example, if the other set of strands is insulated, but it is preferred that both or all of the strands have insulation. The insulation can be extruded, wrapped, and / or braided, but preferably includes an enamel of the type typically used in so-called "magnet wire."

[0046] The machine may also include soft polymer insulation, for example between each layer, to fill gaps between the individual strands.

[0047] Preferably, the respective insulation of each set is colored a different color so that it can be separated, for example, for connection at opposite ends of the winding. If more than one set of strands is provided, each may be colored individually.

[0048] If both sets of electrodes on a conductor have identical enamel insulation, they are usually visually indistinguishable, although it is envisaged that applying an electrical signal at one end will allow them to be individually identified at the other end. Conveniently, the conductors are grouped into a single set of electrodes at the other end, and in fact are preferably connected together, and after a signal is applied, they are sorted at one end, and the other electrode is identified depending on whether a signal is present on the individual conductor.

[0049] The present invention may use a capacitive power transmission cable that includes: At least two sets of conductive strands (these conductive strands must be Laid in layers of opposite twist, All the strands in one or more adjacent layers are one set, and all the strands in one or more adjacent layers going radially outward are another set. Insulation between layers of different sets, so that at least two of the sets are in a capacitive relationship with each other.

[0050] The invention is not limited to the details of the above-described embodiments. For example, more or fewer conductive layers may be provided. As described above, there may be an even number of conductive layers, or an odd number of conductive cylinders with the innermost and outermost interconnected.

[0051] To connect the first capacitive winding to the second capacitive winding conductors, a connector block may be provided with terminals for the first and second sets of conductors, which facilitate connecting the wires as capacitive wires such that, in use, one set of conductors is connected to the first set of connecting windings and the second set of conductors is connected to the second set of connecting windings.

[0052] All of the above windings, including variations, are connected in essentially the same way: one set of strands (usually the red set) is bundled at both ends, and the other strands are similarly bundled. After separating the strands into their respective bundles, the enamel is stripped from the ends of the strands. The stripped strands are then soldered or inserted into their respective terminal blocks and tightly clamped together to establish the mechanical and, more importantly, electrical connection.

[0053] When a winding is used as a single length between the positive and negative or neutral terminals of a power source, the electrical connection of the winding is made between the first set of wires and the second set of wires as a strip or distributed capacitor. At the beginning of the winding, the first set of conductors is permanently connected to the positive, or supply, side of the power source. At the end of the winding, the second set of conductors is permanently connected to the negative, or neutral, side of the power source. The remaining sets are terminated in separate terminals on each side of the winding. Alternatively, or in addition, another set of conductors can be connected to both ends to provide a straight-through connection.

[0054] The capacitance of the cable can be further selected by using three or more sets of cable, for example by adding a third set of conductors in parallel to the conductors of the first set and a fourth set of conductors in parallel to the conductors of the first set, so that the conductors of the third and fourth sets are capacitively connected.

[0055] When selecting the winding capacitance, the inductance of the winding and the inductance of other components of the electrical system to which the electric machine belongs must be taken into account, and this inductance must be balanced or modified with the winding capacitance. More specifically, the following procedure can be used: 1. Select the initial size of the winding depending on the voltage and current it will carry, especially the cross-sectional area of ​​any metal or insulating filler you will include in place of the core, and the number of enamelled wires and / or layers in the first iteration; 2. Use computer simulation and modeling to determine the design inductance (L) of the windings, particularly including their intrinsic inductance and any mutual inductance that may result from their inclusion in the electromechanical system. D ) and the resistance of the winding wire (R), 3.L D Note that the inductive reactance of the winding resulting from is given by the inductive reactance equation below: X L =2πfL D where f is equal to the operating frequency (Hz), 4. For the capacitive reactance of the winding, note that the capacitance C is given by the capacitive reactance equation below, X C =1 / 2πfC where f is equal to the operating frequency (Hz), 5. If there is a need to balance other elements of the machine inductance, this can be done by adding L D That is, X L This can be taken into account by changing the value of 6. The resulting design is modeled in simulation and compared to the original inductance calculation L D and the resulting X L and X C is verified and the design may need to be modified. One or more further iterations may be required.

[0056] The above procedure takes into account the fact that for selected, but not all, dielectric materials, even in the case of magnetic wire enamel, the dielectric strength does not increase linearly with voltage, as shown in Figure 12.

[0057] Note that the choice of dielectric is determined by the applied voltage and the required capacitance. To understand their relative values, this relationship can be observed for a selection of, but not exhaustive, dielectric materials, as shown in Figure 13.

[0058] If the capacitance of the combined length needs to be small, the connector can be a series connector. If there is a connection between two windings from the first set (winding A) to the second set (winding B), the capacitance of the free end is the capacitance between the first set of wires in winding A and the second set of wires in winding B. The capacitance is effectively a single length with twice the dielectric gap. This is expressed by the formula for series capacitance below:

[0059]

number

[0060] Now, if the two lengths are the same, the total capacitance of the windings will be halved.

[0061] A feature of series connected capacitance is that the voltage across each individual capacitance is divided by the number of capacitances. This makes it convenient to configure a high voltage line in three sections, with each section carrying one-third of the high voltage. This has the added benefit of reducing the thickness of the dielectric coating (tape / paper) between the conductors. This allows the capacitance loss due to the series connection to be offset by the higher capacitance per unit length in the first place.

[0062] Various types of wires, cables, and conductors may be used with the present invention.

[0063] 1. IEC 60317 (Specifications for certain types of winding wire) The following IEC standards specify various forms of "enameled" conductive wire used in winding applications, divided into conductive material (e.g., Cu, Al, or conductive spray), conductor shape (e.g., tape, rectangular wire, round wire), and enamel material:

[0064] This standard is an example of how thin or thick enameled stranded wire can be made to better suit a particular implementation or winding application. Variations in enameled wire include strand sizes ranging from 0.01 mm to 0.5 mm.

[0065] This standard is used to indicate the types of wire / conductors that can be effectively used to create capacitive windings / wires depending on the size of the machine, the environment, etc. The present invention can use any suitable form of conductor and dielectric to establish the capacitive link.

[0066] 2. Dual / multiple implementations in one product (cable / wire + electromechanical windings) The concept is to provide a means by which a wire / connection can be used as both a feeder cable / wire and an electromachine winding, i.e. one product can be used for two (or more) applications simultaneously. The cable can have a very thin insulation (tape wrapping) over the conductor bundle.

[0067] This cable / wire can be connected to a conventional AC electric machine or to an electric machine with a capacitive winding, or both applications can be served using one wire. [Example]

[0068] Referring generally to the examples, there is shown an embodiment of the invention of a machine with a capacitive winding, represented in the circuit diagram as a capacitor.

[0069] The circuit diagram of the machine of the present invention is shown diagrammatically in Figure 3. A capacitive cable in the form of two wires separated by a dielectric is wound into a coil. One wire is connected to the positive side of a power supply, the other to the negative side.

[0070] The electrical connection between the two wires is capacitive and is represented in the circuit diagram by a capacitor.

[0071] (Example 1 - Transformer) (Model 1 (step-down) with the same number of turns) A first transformer of the present invention is shown schematically in FIG.

[0072] A transformer has capacitive windings on both sides of a ferrite core. The incorporation of capacitive reactance in the primary winding limits the current available to excite the core, and thus generate the magnetic flux connecting the primary and secondary windings. As a result, the primary voltage can rise above the point where it would generate a saturating current at, say, 50 Hz, compared to a conventional equivalent. Meanwhile, as the current decreases, the voltage induced in the secondary winding also decreases due to the decrease in primary current.

[0073] (Model 2 (same voltage level) same number of turns) A second transformer of the present invention is shown schematically in FIG.

[0074] This Model 2 is a transformer where both cell coils have the same capacitance. This means that the voltage across both coils will be the same. A 12V input to the primary coil will produce a 12V output at the secondary coil. This is useful when the circuit is designed such that it is beneficial to keep the two parts of the circuit electrically isolated from each other.

[0075] (Model 3 (Boost) with the same number of turns) A third transformer of the present invention is shown schematically in FIG.

[0076] Model 3 is the inverse of Model 1, differing in the way the capacitors are connected in the circuit. This system can also be applied to motors that include transformers. This is because developing smaller transformers for motors is advantageous, as it allows for the production of smaller motors or motors with greater power output for the same size. This is particularly useful for electric vehicles and / or drones.

[0077] Model 4 (not shown) is a transformer with a laminated core to reduce the formation of eddy currents. Prior art transformers typically use only magnetic fields to transmit power. However, by connecting this lamination to a circuit, the increase and decrease of the electric field can also be utilized.

[0078] In conventional transformers, loss of lamination coating is of little concern because the laminations do not form part of the electrical circuit, however, in the present invention, the laminations do form part of the circuit and therefore it is preferred that the different laminations in the CTS transformer are dielectrically isolated from each other.

[0079] Model 5 (not shown) has a similar setup to Model 4, but both laminations are connected to one side of the transformer circuit. This contrasts with Model 4, in which one set of laminations is connected to the primary side of the transformer circuit and the other set of laminations is connected to the secondary side of the transformer circuit.

[0080] A common problem encountered in the prior art is the limited magnetic field that can be induced in a ferromagnetic core. This is because the core is composed of many tiny regions called magnetic domains, and a given core size has a finite number of magnetic domains. The magnetic field of each of these domains is randomly oriented until the current in the primary coil induces a magnetic field in the core, at which point the magnetic fields of the magnetic domains in the core align. The more closely the magnetic domains align, the stronger the magnetic field induced in the core. However, this means that there is a limit to the size of the magnetic field that can be created around the core, and this maximum value corresponds to the state where the magnetic domains in the core are perfectly aligned. At this point, further increasing the number of turns in the primary coil does not increase the strength of the magnetic field created around the core, meaning no additional power can be transferred to the secondary coil. At this point, the ferromagnetic core is said to be saturated.

[0081] To address the saturation issue and transfer additional power, a larger ferromagnetic core can be used, providing more magnetic domains and allowing for a stronger magnetic field to be induced before saturation is reached. However, this tends to make conventional transformers physically larger.

[0082] It is therefore desirable to develop a system that can increase the power transmitted through a transformer without requiring a larger ferromagnetic core to be used to prevent core saturation.

[0083] By constructing the primary and secondary cables from capacitive cables, it is possible to eliminate the need to increase the frequency of the input AC current to increase the inductive reaction in the cables. It is also possible to eliminate the need to increase the number of turns in the coil. As a result, the ferromagnetic core does not need to be increased in size, and more power can be transmitted through the transformer. Therefore, the present invention allows for the manufacture of smaller transformers.

[0084] One advantage of this invention is that the use of high-frequency power transmission allows for the use of smaller electrical components. This is due to the fact that the magnetic fields used in transformers, for example, increase and decrease many times per second. For example, aircraft use a frequency of 400 Hz. This allows for components that are eight times smaller than those that would be used at 50 Hz.

[0085] When an aircraft arrives at the gate, it often needs to connect to the airport's power supply, and if the airport's power supply frequency is 50Hz, a converter is needed at each end to convert this to 400Hz.

[0086] The converter takes an AC input, converts it to DC, and then passes this DC through a second stage of the converter (called an "inverter") to convert it back to AC (but at a different frequency than the input AC). One advantage of this invention over a high frequency power distribution network is that it eliminates the need to install a converter at each gate. Instead, the airport can install one converter and provide a network to which each gate's power cable connects.

[0087] In the present invention, there can be no ohmic, i.e. conductive, connection from one end of the coil to the other (e.g., in a CTS transformer). The reactance of the capacitor and the reactance of the inductor can have opposite vector directions. As a result, the capacitance becomes much larger, resulting in an increase in net capacitance. In the transformer of the present invention, the laminated core (layers or laminates) also functions as a capacitor. This allows the use of electric fields as well as magnetic fields. This could be advantageous, for example, in the case of wireless charging.

[0088] The number of turns in each coil is the same in Model 1 and Model 2. Model 1 is considered to consist of four wires arranged in two coils. The primary coil consists of two of these wires, and the secondary coil consists of the remaining two wires.

[0089] In the primary coil of Model 1 (left), the red and green wires are connected in series with a capacitor C1 between them. Both wires are wound around one of the cores to form the primary coil. However, in the secondary coil, the red and green wires are connected in parallel with a capacitor between them. Like the primary coil, both wires of the secondary coil are wound around the side of the core to form the secondary coil.

[0090] Having a primary coil with two wires connected in series and a secondary coil with two wires connected in parallel results in the primary coil being effectively twice as long as the secondary coil (assuming all four wires are the same length). This means that the primary coil effectively has twice as many turns as the secondary coil (again, assuming all four wires have the same number of turns). A 2:1 ratio of turns between the primary and secondary coils results in a 2:1 ratio of voltages across the primary and secondary coils. Model 1 therefore represents a step-down transformer where the voltage drops by 50% through the transformer.

[0091] Model 3 is essentially the inverse of Model 1. In this case, the two wires of the primary coil are connected in parallel, and the two wires of the secondary coil are connected in series. Model 3 therefore represents a step-up transformer, where the voltage is doubled through the transformer.

[0092] The present invention allows for the use of different turns ratios for the two coils, for example ratios other than 2:1 or 1:2. The fact that the voltage change through the transformer, which determines the capacitance of each coil, does not affect this.

[0093] While the amount of capacitance in each coil may not affect the voltage change through the transformer, it can serve another important purpose: limiting current flow. If the reactance of a coil is too low, the current through it will be too high and the wire will burn out. Traditional transformers address this problem by increasing the number of turns in each coil. However, if capacitors are included, it may not be necessary to increase the number of turns to increase the reactance; the capacitors perform this role instead. If more turns are not needed, the coils can be made shorter, meaning the overall transformer can be made smaller.

[0094] In prior art transformers, they are typically configured to operate at a specific input voltage, say 100 volts. Of course, voltage is proportional to current (V=IR). Operating a transformer at an input voltage of 100 volts, assuming a fixed number of turns in the coil and therefore a fixed resistance, would increase the current to compensate, potentially burning out the wire. While this would be equally impractical to change the number of turns, this may not be an issue with the present invention, since the amount of capacitance can be changed to account for this difference. This may make it easier to change the voltage transmitted through the transformer than with a conventional transformer. This is known as dynamic configuration in the present invention.

[0095] Note that this does not change the voltage ratio between the coils (2:1, 5:1, etc.), which is affected only by the number of turns in each primary and secondary coil.

[0096] In most implementations, the voltage is known, allowing the required capacitance to be determined. This applies equally to wireless charging of electric motors and electric vehicles. For wireless charging, the transmitter is considered a similar setup to this transformer, but without the ferromagnetic coil—two coils with a magnetic field between them. In this case, the absence of a core means that energy transmission may be less efficient than with a voltage transformer, since the core serves to direct the magnetic field.

[0097] In the above case, the red and blue laminations represent laminations electrically connected to the red and blue wires of the primary and secondary coils, respectively. These laminations are dielectrically separated from each other by an insulating layer, and therefore function as capacitors. As a result, the energy of eddy currents generated in these laminations can be harnessed and used to transmit energy through the transformer. In prior art transformers, these eddy currents only cause energy loss.

[0098] Model 5 has the same setup as Model 4, but both sets of laminations are connected to the same coil of wire instead of opposite coils.

[0099] (Comparison between capacitive transformers and conventional transformers) The present invention has been illustrated by disassembling and reconstructing the primary / secondary windings of a conventional transformer that uses capacitive windings.

[0100] This conventional transformer had the following features:

[0101] [Table 1]

[0102] This conventional transformer was operated within a range of frequencies to demonstrate the behavior of the turns ratio and the opportunity to incorporate CTS connections in the windings.

[0103] In this conventional transformer, two primary windings are connected in parallel (P1 / / P2), followed by two secondary windings connected in series (S1+S2). This configuration results in a 1:2 (N P :N S ), a step-up transformer topology is established, and the equivalent circuit of a conventional transformer is shown schematically in Figure 7.

[0104] The operation of the transformer (connected to a 66 Ω load) was experimentally tested. During the experiment, when Vp was increased to 115 volts at 50 Hz, the transformer core saturated because the primary current exceeded the magnetic field strength threshold for the given core. As the power frequency was increased, for a given primary voltage and turns ratio, the change in secondary voltage was minimal and the transformer winding relationships remained applicable, i.e., it continued to operate as a step-up transformer. Operational performance is shown in Figure 8.

[0105] However, when converting this winding topology from a conventional one to a transformer of the present invention, i.e., when introducing the capacitive elements described in this invention into the transformer winding, the turns ratio relationship is no longer the primary factor defining winding parameters such as voltage and current. Instead, winding reactance (capacitive and inductive) and associated parameters such as frequency contribute to the transformer mode / topology (step-down, isolation, or step-up).

[0106] A transformer of the present invention was designed and constructed with the same ratings (and number of turns) as the conventional equivalent described above, but using the capacitive winding of the present invention for both windings. The primary and secondary windings were connected in series and parallel, respectively, and the step-down transformer was installed according to the rules for transformer turns ratio.

[0107] FIG. 9 shows the equivalent circuit of this transformer incorporating capacitive windings on both windings (step-down) in accordance with the present invention.

[0108] The incorporation of capacitive reactance in the primary winding limits the current available to excite the core, i.e., to generate the magnetic flux linking the primary and secondary windings. As a result, the primary voltage can rise above the point where it would generate a current that saturates the current, say at 50 Hz, compared to a conventional equivalent. Meanwhile, as the current decreases, the voltage induced in the secondary winding also decreases due to the decrease in primary current.

[0109] Furthermore, because the windings have both inductive and capacitive elements, the resulting reactance changes as the power supply frequency changes. One observed change is a variable voltage ratio (Vp:Vs) that is independent of the winding turns ratio. At approximately 100 Hz, the transformer operates in step-down mode. As the frequency increases, the inductive reactance increases and the capacitive reactance decreases.

[0110] Instead, the change in current distribution between the inductive and capacitive elements increases the voltage induced in the secondary winding for the same primary voltage, and at about 600 Hz the reactance is effectively minimized (as indicated by a rise in the power factor) and the transformer behaves as an isolating transformer. As the frequency increases further, X L is X C It becomes larger and changes its operation to that of a step-up transformer. The reactance of the windings is minimized, allowing it to produce a larger power capacity.

[0111] As shown in the above operation, when the frequency is less than 600Hz, the transformer operates in CTS mode (X L <X C ) but when the frequency reaches and exceeds 600Hz, X L Since is the dominant reactance in the winding (X L >X C ), the transformer will revert to the conventional type.

[0112] The increase in power supply frequency allows the reactive elements in the windings to charge and discharge at a faster rate than the traditional 50Hz, allowing both conventional and CTS models to transmit higher power while avoiding saturation. This also demonstrates that CTS connections can operate at higher frequencies. However, it should be noted that further increasing the frequency beyond a certain threshold increases eddy currents, contributing to power losses in the core (making core frequency compatibility important).

[0113] A transformer according to the present invention was manufactured and subjected to a comparative test with a conventional transformer. The performance of the transformer according to the present invention is shown in Figure 10.

[0114] One of the key design achievements is the reduction in size of the CTS transformer core while transmitting the same power as a conventional transformer using a larger core; Figure 11 shows a side-by-side comparison of a conventional transformer and an equivalent transformer made in accordance with the present invention.

[0115] (Example 2 - Motor) 1 and 2 show schematic diagrams of a motor with a capacitive winding according to the invention (FIG. 1: conventional winding, FIG. 2: star connection).

[0116] FIG. 14 shows the equivalent circuit of a conventional induction motor with conventional windings. V1 = input voltage (power supply voltage) R1 = resistance of stator winding, Ω X1 = stator leakage reactance (winding), Ω Xm = Stator magnetizing reactance, Ω Rc = core losses (hysteresis and eddy currents) I1,Is = stator current, A I0=magnetizing current, A E1 = stator induced EMF S = Slip E2 = EMF induced in the rotor T = motor torque, Nm I2 = rotor current, A X2 = rotor circuit reactance, Ω R2=rotor circuit resistance, Ω 15 and 16 show equivalent circuit diagrams representing an electric machine with a capacitive winding according to the present invention. V1 = input voltage (power supply voltage) R1 = resistance of stator winding, Ω X cts = Stator CTS reactance (winding), Ω Xm = Stator magnetizing reactance, Ω Rc = core losses (hysteresis and eddy currents) I1,Is = stator current, A I0=magnetizing current, A E1 = stator induced EMF S = Slip E2 = EMF induced in the rotor T = motor torque, Nm I2 = rotor current, A X2 = rotor circuit reactance, Ω R2=rotor circuit resistance, Ω

[0117] (Example 3 - Wireless Charging Plate) A capacitive cable and high-frequency AC were used for the feeder cable and primary electric vehicle (EV) wireless charging plate (also called a charging pad). In this example, during self-compensating mode, the CTS cable exits the inverter, is wound to form a coil, and returns to the inverter to complete a circuit; that is, the cable is an unbroken continuous loop through the coil and back to the inverter. Thus, essentially, the coiled cable, or primary pad, incorporates capacitive and inductive properties (i.e., hybrid wireless power transfer (WPT) with physical elements representing an inductor (coil) and a capacitor (CTS terminal)).

[0118] The CTS capacitance simultaneously compensates for the reactance of the coil and the cable.

[0119] A plate incorporating the coil of the present invention is shown diagrammatically in FIG.

[0120] In section 1, there is capacitive coupling between a first cable connected to a power source and a second cable (not connected to a power source). The pair of cables continues to a pad.

[0121] In section 2, the pad consists of two cables, again capacitively coupled and wrapped around the pad coil, exiting towards section 3.

[0122] In section 3, the cables leave the pad and remain capacitively coupled, and a second cable is connected to the other end of the power supply, but the first cable is not, so a capacitive winding is provided on the coil of the charging pad.

[0123] Example 4 In developing the transformer described in Example 1, a further transformer design of the present invention used high frequency CTS cables for both the feed cable and the windings, as shown schematically in FIG.

[0124] Thus, capacitive conductors using insulated conductors, wires or cables are used in the form of windings in electric machines.

Claims

1. An electric machine comprising a conductor wound into an electromagnetic coil, the conductor being a capacitive conductor represented in a circuit diagram by a capacitor.

2. An electric machine having a capacitive winding which is a coiled capacitive wire, the capacitive wire being any wire having capacitive coupling within the conductor / conductor element of the wire and represented by a capacitor in a circuit diagram.

3. The electric machine of claim 1 or 2, wherein the capacitive conductor or capacitive wire comprises two conductors coupled to each other via capacitive coupling.

4. The electric machine of claim 3 , wherein the two conductors are electrically separated from each other by a dielectric material, which together form the capacitive coupling.

5. 10. An electric machine according to any preceding claim, comprising a coiled, spiral or helical conductor.

6. The electric machine of claim 5 comprising two or more conductors wound in a coil, spiral, or helical configuration.

7. 10. An electric machine according to any preceding claim, wherein the electric machine is a transformer (optionally including a ferromagnetic core), a motor, a generator, a solenoid, an electromagnet, an antenna, a furnace, a heater, a (wireless) charger, or a dynamo.

8. 8. The transformer of claim 7, further comprising a capacitor connected to and / or integrated with the primary coil.

9. 9. The transformer according to claim 7 or 8, wherein the transformer is a step-up transformer, a step-down transformer, or an isolation transformer.

10. 10. A transformer as claimed in any one of claims 7 to 9, comprising a secondary coil (or winding) connected to a capacitor.

11. Transformer according to any one of claims 9 to 10, wherein the primary coil is connected in series with a capacitor and / or the secondary coil is connected in parallel with a capacitor.

12. The motor according to claim 7.

13. The generator of claim 7.

14. 8. The electromagnet according to claim 7.

15. 8. The antenna of claim 7.

16. 8. The furnace of claim 7.

17. The heater of claim 7.

18. The charger according to claim 7.

19. The wireless charger of claim 7.

20. 8. The solenoid of claim 7.

21. 8. A dynamo according to claim 7.

22. A method for manufacturing an electric machine according to the preceding claims, comprising the steps of: providing a cable, wire, or conductor comprising two conductors separated by a dielectric; forming a capacitive connection therebetween; and Coiling or otherwise coiling the cable, wire, or conductor. A method for manufacturing an electric machine, comprising:

23. An electric machine with a capacitive winding.

24. 24. An electric machine according to claim 23, comprising a capacitive connection (winding, coil or other means of inducing a magnetic field) represented in the circuit diagram by a capacitor.

25. 24. The electric machine of claim 23, wherein the capacitive winding includes a conductor within which there is capacitive coupling, represented in a circuit diagram by a capacitor.

26. 26. The electric machine of claim 25, wherein the conductor of the capacitive winding comprises two conductors coupled together via capacitive coupling.

27. 27. An electric machine according to claim 25 or 26, wherein the conductor comprises two conductors, such as wires, electrically separated from each other by a dielectric material, which together form the capacitive coupling.

28. 28. The electric machine of claim 23, wherein the capacitive winding comprises a coiled, spiral, or helical conductor.

29. 30. The electric machine of claim 28, comprising two or more capacitive windings, each including one or more conductors wound in a coil, spiral, or helical configuration.

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