Motor

Abstract

The AC machine includes capacitive windings or capacitive connections such as wires capacitively coupled and separated by dielectric material and wound into electromagnetic coils, the capacitive windings or capacitive connections being represented in a circuit diagram by capacitors. This replaces conventional coils in electrical machines such as motors, generators, transformers, coils, antennas, etc.

Description

Technical Field

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

[0002] "Electric machine," "motor," and similar terms are often used to refer to machines that use electromagnetic forces, such as electric motors, generators, transformers, and similar machines. These machines can convert electromagnetic energy into mechanical energy, or mechanical energy into electromagnetic energy, or transfer magnetic energy from one winding to another separated by electrical or galvanic isolation. For example, an electric motor converts electricity into mechanical power, and a generator converts mechanical power into electricity. Another example is a transformer, which changes the voltage level of alternating current. Developing more efficient electric motors has uses and advantages in many electromagnetic applications.

[0003] US 7,154,364 discloses an electric machine having a high voltage winding using conventional wires.Other known machines include similar electrical windings in various shapes and forms.

[0004] It is an object of the invention to provide an alternative electric machine with a different wiring arrangement and / or winding arrangement; it is an object of a particular embodiment to provide an improved electric machine, for example one that can be made smaller and / or lighter. Summary of the invention

[0005] According to the present invention, there is provided an electric machine comprising a capacitive winding (or a capacitive connection). The capacitive winding may be, for example, 2 or more windings that are capacitively connected.

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

[0007] The present invention also provides an electric machine comprising a capacitive winding, which is a capacitive wire wound into a coil, wherein the capacitive wire is any wire having capacitive coupling within its conductor / conductive element and is represented by a capacitor in a circuit diagram.

[0008] There is also provided a method of manufacturing a machine of the invention (such as the one described above), the method comprising

[0009] providing a capacitive conductor (e.g., a wire or cable or conductor), and

[0010] - Forming or making the capacitive conductor into a winding.

[0011] The use of capacitive connections in the windings of an electric machine provides new machines and offers new options for machines with significant potential benefits.

[0012] Details of the Invention

[0013] The electric machine of an embodiment of the invention comprises a capacitive winding. Suitably, the machine comprises a capacitive connection (eg a winding or coil) which is represented in the circuit diagram by a capacitor.

[0014] The electric machine of the present invention may comprise a conductor wound into an electromagnetic coil, wherein the conductor is a capacitive conductor which is represented by a capacitor in the circuit diagram.

[0015] The motor may include a capacitive winding, which is a capacitive wire wound into a coil, where a capacitive wire is any wire that has capacitive coupling within its conductors / conductive elements and is represented in circuit diagrams by a capacitor.

[0016] Typically, and as shown in more detail in the following examples, a capacitive conductor or capacitive wire or capacitive winding comprises two conductors coupled to each other via capacitive coupling. The two conductors may be electrically isolated from each other by a dielectric material, the dielectric material and the two conductors together forming the capacitive coupling.

[0017] In one application of the invention, a machine including a capacitive winding operates using alternating current (AC) and provides an alternative or replacement for known machines including conventional conductors in their windings.

[0018] The conductor may include a wire and / or cable (e.g., typically having an electrical insulation or sheath or insulator). Thus, the 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 printed circuit board. The conductor is typically an insulated wire, such as used in the examples below.

[0019] In this article, references to windings are considered conventional and refer, for example, to a wire or cable (more generally, a conductor) that forms one or more turns of a continuous coil (such as an electromagnetic coil). A winding can be an electrical conductor formed or wound in the shape of a coil, spiral or helix. Electromagnetic windings / coils are used in electrical machines, such as electric motors, generators, inductors, electromagnets, transformers, chargers, wireless chargers, and sensor coils. An alternating current can pass through the coil to generate a magnetic field, or conversely, an external time-varying magnetic field can pass through the interior of the coil to generate an electromagnetic force (EMF) or voltage in the conductor. The coil or winding can be wound around a coil former. The coil or winding may also include a core, which is suitably a ferromagnetic material or a ferrimagnetic material, in one example iron, which is typically used to guide and increase the magnetic field generated during use.

[0020] Although we consider "capacitive wire" to be conventional, a "capacitive wire" in this article is any wire or cable having capacitive coupling within its conductor / conductive element. Similarly, a "capacitive conductor" in this article is any conductor having capacitive coupling within its conductor / conductive element. The term "capacitive" does not refer to the cable capacitance characteristics of conventional conductors (such as conventional transmission lines). The term "capacitive" does not refer to the capacitance between two isolated conductors in a conventional transmission line. Instead, the term "capacitive" refers to a wire or cable or conductor that is part of a capacitive transmission system and the wire or cable or conductor is represented by a capacitor in a circuit diagram. Examples are described, for example, in WO 2010 / 026380, WO 2019 / 234449, WO 2021 / 094783, WO 2021 / 094782, and WO 2020 / 120932. In these disclosures, capacitive wires are sometimes referred to as capacitive transmission system (CTS) connections or CTS cables. Thus, embodiments of the present invention use a CTS connection or CTS cable or conductor that is wound into a "capacitive winding" and used for one or more windings in an electric machine. In one use, as further described below, the capacitive properties of the CTS connection can control the current in the coils of an AC motor.

[0021] The capacitive winding may comprise a conductor and / or there may be a capacitive coupling within the conductor.The conductor of the capacitive winding preferably comprises two or more conductors, which are preferably coupled to each other, suitably via a capacitive coupling.

[0022] Alternatively or additionally, the conductor may comprise two conductors, such as wires, and these conductors may be electrically isolated from each other, for example, by any dielectric material and / or insulating medium (or insulator); in some embodiments, the any dielectric material and / or insulating medium (or insulator) may be air. The dielectric material and the wires then together form a capacitive coupling. Suitably, the capacitive winding comprises an electrical conductor, and the electrical conductor may be in the form of a coil, a spiral, a helix or any other suitable geometry.

[0023] Thus, as an example of the present invention, the motor winding comprises two capacitive wires (a first wire and a second wire), which are electrically insulated from each other by a dielectric material, thereby forming a capacitive coupling, wherein one end of the first wire can be connected to the positive power supply side and one end of the second wire can be connected to the negative power supply side; the two wires are wound into a coil or winding and used as an alternative or replacement for a conventional winding or winding (see, for example, Figure 3 , the figure roughly shows such a winding).

[0024] The corresponding method of the present invention for manufacturing a machine comprises

[0025] providing a conductor comprising two or more conductors (e.g., wires) separated by a dielectric material or insulating medium and forming a capacitive coupling between the two conductors, and

[0026] The conductor is wound or made or formed into a coil.

[0027] In one embodiment of the invention, a capacitive cable comprises an interwoven first conductor and a second conductor, the proximal end of the first conductor being connected to the positive terminal of a power source (or being prepared to be so connected), the distal end of the second conductor being connected to the negative terminal of the power source (or being prepared to be so connected), the capacitive cable being wound into a coil, in one example into a coil of about 100 turns. This forms the primary coil of a transformer. The second coil of the transformer may be conventional, or may also be made using a capacitive cable. If the primary coil is conventional, as defined herein, then the second coil is capacitive (as defined herein).

[0028] Suitably, each or all of the capacitive windings have a capacitive reactance. The motor may preferably have both an inductive element and a capacitive element. The or each capacitive winding may generate both a magnetic field and / or an electric field. Alternatively, the capacitive winding may use a magnetic field and / or an electric field to transfer energy.

[0029] Electric machines comprising windings are common. The present invention replaces conventional windings with capacitive windings. Therefore, the present invention is considered to have a wide range of applications. The electric machine is suitably a transformer, a motor, a generator, a solenoid, an electromagnet, an antenna, a filter (e.g. a filter in a hi-fi), a stove, a heater, a charger, a wireless power transmission system (e.g. a wireless charger) and / or a DC generator. If the electric machine is a filter, the electric machine (or the winding) may have resistance, inductance and capacitance. The transformer or AC motor may be coreless, such as a wireless energy transformer, a coreless transformer or a coreless motor.

[0030] In a particular embodiment, the electric machine is a transformer. The transformer may also have a capacitor connected to the primary coil and / or integrated with the primary coil. Suitably, 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.

[0031] In certain embodiments, the electrical machine is a motor or a generator. The motor may be an induction motor, and specific embodiments of the invention in the form of a motor are provided in the following examples.

[0032] In a particular embodiment, the motor is a wireless pad, such as a charging pad, sometimes also referred to as a grounding pad or even a transmitter pad. The charging pad interacts with another wireless pad (sometimes referred to as a vehicle pad or receiving pad) in use to wirelessly transmit power. Either or both may include the capacitive winding of the present invention. A preferred use is to charge an electric vehicle. The present invention provides a wireless charging station including the capacitive winding of the present invention and / or an electric vehicle including the capacitive winding of the present invention.

[0033] Another use is to charge mobile phones, smart phones and other handheld electrical devices. The present invention provides a charging station for handheld electrical devices, the charging station comprising the capacitive winding of the present invention. The present invention also provides a mobile phone or other handheld electrical device comprising the capacitive winding of the present invention.

[0034] The motor of the present invention may include a secondary capacitive coil or capacitive winding, which is optionally connected to a capacitor. In the following examples, both the primary transformer winding and the secondary transformer winding 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.

[0035] The number of turns in the winding of the present invention varies with the expected winding characteristics and uses. For conventional windings, the winding of the present invention typically includes at least 5 turns, at least 20 turns, or at least 50 turns. Other windings of the present invention include at least 100 turns, at least 300 turns, at least 500 turns, and more turns.

[0036] In the use of the present invention, it has been found that it is possible to manufacture and use electric motors that are smaller and lighter than known electric motors and still provide comparable or even improved performance. As a specific example, described in more detail below, a transformer was manufactured using the capacitive windings of the present invention and was shown to perform as well as a transformer manufactured using conventional windings and having approximately twice the size and weight of the transformer of the present invention.

[0037] This means that in certain situations, where weight and / or space is an issue, or even where weight and / or space is very limited, the motor of the present invention may be advantageous, such as in the aircraft industry, and in particular in motors on or in aircraft. This may be independent of the frequency used, so that during use the weight savings may apply to low frequencies (e.g. about 50 Hz) as well as high frequencies.

[0038] Generally, the motor of the present invention can operate over a wide range of AC frequencies. Embodiments of the present invention operate using high frequency AC, such as 350 Hz or higher, or 400 Hz or higher, up to 2.8 MHz respectively. In these embodiments, cables are suitably used, wherein each cable comprises:

[0039] (a) a first plurality of conductors for connection to a power source,

[0040] (b) a second plurality of conductors for connection to a load, and

[0041] (c) a dielectric material between the first plurality of conductors and the second plurality of conductors,

[0042] Each conductor is individually insulated and

[0043] Wherein, at least one conductor of the first plurality of conductors and at least one conductor of the second plurality of conductors are braided or wound into one or more bundles such that each individual conductor repeatedly transitions between the outside of the one or more bundles and the inside of the one or more bundles along the length of the one or more bundles.

[0044] For this high frequency embodiment of the invention, the motor is suitably manufactured using the cabling described in co-pending European Patent Application Nos. 22209216.5 and 23175297.3. In a preferred embodiment, the motor is manufactured using Litz wire.

[0045] Hitherto, if too much current flows through the windings in conventional motors, the wires may burn out. In conventional transformers, in order to solve this problem, more turns are provided in the windings. However, this increases the size and / or weight of the transformer. In contrast, in the motor of the present invention, more turns can be provided without this disadvantage. Therefore, the increase in reactance can be achieved by having or including additional capacitors or by changing their capacitance, rather than including more turns to increase the reactance. In particular, this can be achieved if capacitive wires are used. Therefore, it is not necessary to increase the number of turns of the primary coil to increase the voltage in the primary coil, which means that a smaller core can be used.

[0046] In some embodiments, the capacitive winding itself may not have sufficient capacitance. One or more additional capacitors may supplement this. However, these capacitors should be considered as part of the capacitive wire (or cable) and are not generally considered to be connected in series or in parallel. Instead, these capacitors are best considered to form part of the CTS connection.

[0047] In some embodiments, the use of capacitive wires (or cables) may mean that the voltage ratio of the motor windings no longer depends on the turns ratio of the windings. Instead, the capacitance ratio of the two coils may be used to determine the voltage ratio. Thus, for example, in a transformer, the primary winding advantageously has the same number of turns as the secondary winding, but the capacitance ratio between the two windings may determine whether the transformer will be a step-up transformer or a step-down transformer.

[0048] In an embodiment of the present invention, the motor includes two or more capacitive windings and a capacitive controller for changing a capacitance ratio between the two or more capacitive windings, such as in a transformer.

[0049] The motor may also include a dynamic arrangement. For example, if the capacitance of the circuit on either side of the transformer can be adjusted, then the power distribution (e.g., the voltage in the two windings) may also be adjustable (usually without changing the number of turns of either winding).

[0050] In an embodiment of the invention, the electric machine comprises a capacitive power transmission line comprising:

[0051] at least two groups of electrically conductive strands, the groups being distributed in the cross section of the winding such that the groups are in a capacitive relationship to each other, and

[0052] Wherein all the strands of at least one of these groups have:

[0053] • A corresponding insulating coating with a certain dielectric strength to enable the groups of conductive strands to remain isolated from each other.

[0054] In these embodiments, at least a portion of the power transmission conductor is in the form of a winding.

[0055] The conductors or strands typically comprise copper and / or other conductive material. Typically there are two or more sets of strands in a winding, and these strands preferably alternate in their layers.

[0056] Although one of the groups of conductive strands may be uninsulated, such as with insulation of the other group of strands providing isolation, preferably both or all groups of strands have their own insulation. The insulation may be extruded, wound and / or braided, but preferably comprises an insulating varnish of the type commonly used for so-called "electromagnetic wire".

[0057] The electric machine may include soft polymer insulation, such as between each layer, for example to fill the gaps between the individual strands.

[0058] Preferably, the respective insulation of these groups will be of different colours, for example to allow them to be spaced apart for connection at opposite ends of the winding.Where more than two groups of strands are provided, the more than two groups of strands may each have a respective colour.

[0059] When two sets of electrode conductors have the same insulating varnish insulation, the two sets of electrode conductors are usually visually indistinguishable. However, it is conceivable that the two sets of electrode conductors can be individually identified at one end by applying an electrical signal to the two sets of electrode conductors at the other end of the two sets of electrode conductors. Conveniently, these conductors will be grouped together at the other end to form an electrode group, and in fact these conductors will preferably be connected together at the other end, the signal applied, and then sorted at one end according to the presence or absence of the signal on each conductor to identify the other electrode.

[0060] The present invention may use a capacitive power transmission cable comprising:

[0061] At least two sets of conductive strands, the conductive strands

[0062] · laid in multiple layers running in opposite directions, where

[0063] The strands of one or more adjacent layers are each a group, and then in the radially outward direction, the strands of one or more adjacent layers are each another group, and

[0064] - Different groups of layers are insulated from each other, whereby at least two groups are in capacitive relationship with each other.

[0065] The invention is not limited to the details of the above embodiments. For example, more or fewer conductive layers may be provided. These conductive layers may be provided as an even number (as described above) of conductive cylinders or an odd number of conductive cylinders, wherein the innermost and outermost sides are connected to each other.

[0066] In order to connect the first capacitive winding conductor to the second capacitive winding conductor, a connector block may be provided, the connector block being provided with terminals for the first set of conductors and the second set of conductors. The block facilitates connecting the wires as capacitive wires, wherein one set of conductors is connected in use to a first set in a connecting winding and the second set of conductors is connected to a second set in a connecting winding.

[0067] The above windings (including variants) are connected in essentially the same manner, with one group (usually the red group) of strands being bundled at both ends and the other group of strands being bundled in a similar manner. After being separated into respective bundles, the insulating varnish is stripped from both ends of the strands. The stripped strands are welded or inserted into respective terminal blocks and are clamped tightly together, providing mechanical and, more importantly, electrical connections.

[0068] When the winding is used as a single length between the positive and negative or neutral portions of a power supply, the electrical connection of the winding is between the first and second sets of conductors as a long capacitor 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 supply. At the end of the winding, the second set of conductors is permanently connected to the negative or neutral side of the power supply. The remaining sets are terminated in isolated terminals on the respective sides of the winding. Alternatively or additionally, a separate set of conductors may be connected at both ends to provide a through connection.

[0069] A cable having three or more groups of conductors may be used to further select the capacitance of the cable, such as by adding a third group of conductors in parallel with the first group of conductors and a fourth group of conductors in parallel with the first group of conductors, the third group of conductors and the fourth group of conductors being capacitively connected.

[0070] To select the capacitance of the winding, the inductance of the winding and the inductance of other components of the electrical system of which the motor is a part are taken into account, with a view to balancing or varying this inductance with the capacitance of the winding. More specifically, the following steps may be used:

[0071] 1. Selecting the initial winding dimensions based on: the voltage and current to be carried by the winding, in particular the cross-sectional area of ​​the metal or insulating filler to be included instead of the core; and, in a first iteration, the number of enameled wires and / or the number of layers;

[0072] 2. Use computer simulation and modeling to calculate the design inductance (L D ) and the resistance of the winding wire (R), and in particular includes the inherent inductance of the winding and any mutual inductance that may be caused by the winding being included in the motor system,

[0073] 3. Note that L D The resulting inductive reactance of the winding is given by the inductive reactance equation:

[0074] X L =2πfL D

[0075] Where f equals the operating frequency in Hz;

[0076] 4. Note that the capacitive reactance of the winding, capacitance C, is given by the capacitive reactance equation:

[0077] X C =1 / 2πfC

[0078] Where f equals the operating frequency in Hz;

[0079] 5. If you want to balance other components of the motor inductance, you can modify L D The value of X is modified accordingly L to take this into account; and

[0080] 6. The resulting design is then modeled during simulation to verify the original inductance calculation value L D And the resulting X L and X C , which may suggest modifications to the design. One or more further iterations may be required.

[0081] The above steps take into account the fact that even for electromagnetic wire insulation varnishes, the withstand strength of the dielectric material does not increase linearly with voltage, e.g. Fig.12 As shown in for selected but not exclusive dielectric materials.

[0082] It should be noted that the choice of dielectric material is determined by the applied voltage and the desired capacitance. To understand the relative values ​​of applied voltage and desired capacitance, one can observe that Fig.13 Relationships shown for selected, but not exclusive, dielectric materials.

[0083] If the capacitance of the combined length needs to be smaller, the connector can be a series connector. By connecting the first set (winding A) to the second set (winding B) between the two windings, the free end capacitance is between the first set of wires of winding A and the second set of wires of winding B. The capacitance is actually a single length that is twice the gap in the dielectric material. This capacitance is given by the formula for series capacitance:

[0084] Series Capacitor

[0085]

[0086] In the case where both lengths are the same, the total winding capacitance is halved.

[0087] A characteristic of series capacitors is the voltage across the individual capacitors divided by the number of capacitors. This is useful to enable a high voltage line to consist of three sections, each carrying 1 / 3 of the high voltage. This has the additional advantage of reducing the thickness of the dielectric coating or tape / paper between the conductors. Thus, the capacitive losses caused by the series connection can be offset first by a higher capacitance per unit length.

[0088] Various types of wires, cables, and conductors may be used in the present invention.

[0089] 1. IEC 60317 (Specifications for special types of winding wires)

[0090] The following IEC standards specify various forms of "enameled" wire for winding applications. This form is divided into the conductive material (copper, aluminum or conductive spray, etc.) and the shape of the conductor (tape, rectangular wire, round wire, etc.) and the insulating enamel material.

[0091] This standard is an example of how thin / thick the enamel wire can be so that it may actually be more suitable for a given embodiment or winding application. Variations of enamel wire include strand sizes ranging from 0.01 mm to 0.5 mm.

[0092] This standard is used to give the type of wires / conductors that can be effectively used to form capacitive windings / conductors depending on the size of the machine, the environment, etc. The present invention can use any suitable form of conductors and dielectric materials to establish the capacitive connection.

[0093] 2. Two / multiple embodiments in one product (cable / wire + motor winding)

[0094] The concept is to provide a way whereby the wire / connection can be used as both feeder cable / wire and motor winding, ie using one product for two (or more) applications simultaneously.The cable can have very thin insulation (tape wrap) on the conductor bundle.

[0095] The cables / wires can be connected to a conventional AC motor or to a motor with a capacitive winding or one wiring can be used to suit both applications.

[0096] Brief description of the attached figure

[0097] To facilitate understanding of the present invention, embodiments of the present invention are described above and below by way of example with reference to the accompanying drawings, in which:

[0098] Figure 1 is a schematic diagram of an induction motor with a delta-connected capacitive winding according to the present invention;

[0099] Figure 2 is a schematic diagram of an induction motor with a capacitive winding of a star connection according to the present invention;

[0100] Figure 3 A schematic circuit diagram showing a generalized form of a capacitive winding of the present invention;

[0101] Figure 4 A schematic diagram of a first transformer of the present invention is shown;

[0102] Figure 5 shows a schematic diagram of a second transformer of the present invention;

[0103] Figure 6 shows a schematic diagram of a third transformer of the present invention;

[0104] Figure 7 A schematic diagram of a conventional transformer (not part of the present invention) is shown;

[0105] Figure 8 Shows Figure 7The operating performance of the transformer;

[0106] Fig. 9 shows a design that replaces Figure 7 A schematic diagram of a transformer of the present invention;

[0107] Fig.10 Shows Fig. 9 The operating performance of the transformer;

[0108] Fig.11 A transformer according to the invention (left-hand side) and a conventional transformer with equivalent performance (right-hand side) are shown, showing their respective dimensions;

[0109] Fig.12 shows the withstand strength of the dielectric material as the voltage increases for selected dielectric materials;

[0110] Fig.13 shows the relationship between applied voltage and desired capacitive properties for selected dielectric materials;

[0111] Fig.14 A circuit diagram showing an induction motor with conventional windings (not part of the present invention);

[0112] Fig.15 and Fig.16 A circuit diagram of a motor with a capacitive winding according to the present invention is shown;

[0113] Fig.17 a circuit diagram showing an electric vehicle charging pad incorporating the capacitive coil of the present invention; and

[0114] Fig.18 A circuit diagram of the transformer of the present invention using a high frequency CTS cable both as a feed cable and for the windings is shown. DETAILED DESCRIPTION

[0115] Generally with reference to examples, embodiments of the invention are shown in which an electric machine comprises a capacitive winding, which is represented as a capacitor in the circuit diagram.

[0116] Figure 3 The circuit diagram of the motor of the present invention is schematically shown. A capacitive cable in the form of two conductors separated by a dielectric material is wound into a coil. One conductor is connected to the positive side of the power supply and the other conductor is connected to the negative side.

[0117] The electrical connection between the two conductors is capacitive, which is illustrated in the circuit diagram by a capacitor.

[0118] Example 1 - Transformer

[0119] Model 1 (step-down), if the number of turns is the same

[0120] Figure 4 A first transformer of the present invention is schematically shown.

[0121] The transformer has a capacitive winding on each side of the ferrite core. Capacitive reactance is incorporated into the primary winding, which limits the current used to excite the core, i.e., to create the magnetic flux connecting the primary and secondary windings. Therefore, compared to conventional transformers, for example at 50Hz, the increase in primary voltage may exceed the point where a current that saturates the current is generated. On the other hand, since the primary current is reduced, the reduced current will reduce the voltage induced in the secondary winding.

[0122] Model 2 (same level), if the number of turns is the same

[0123] Figure 5 A second transformer of the invention is schematically shown.

[0124] This model 2 is a transformer where the capacitance of both unit coils is the same. This means that the voltage of both coils will also be the same. A 12V input at the primary coil induces a 12V output in the secondary coil. This can be useful if the circuit is designed and it is beneficial to keep the two parts of the circuit electrically isolated from each other.

[0125] Model 3 (Boost), if the number of turns is the same

[0126] Figure 6 A third transformer of the present invention is schematically shown.

[0127] Model 3 is the inverse of model 1; the capacitors are connected differently in the circuit. This system can also be applied to motors involving transformers. This is because developing smaller transformers for motors is beneficial as this allows for the production of smaller motors or the same size motor with more power. This is particularly useful for electric vehicles and / or drones.

[0128] Model 4 (not shown) is a transformer in which the core is in the form of laminations to reduce the formation of eddy currents. Prior art transformers usually use only magnetic fields to transmit electricity. However, by connecting the laminations to the circuit, this makes it possible to also use the growing and decaying electric fields.

[0129] In a conventional transformer, if the coating of the laminations is damaged, this may have little effect because the laminations do not form part of the circuit. However, in the present invention, it is preferred that the different laminations remain dielectrically isolated from each other in their CTS transformers because the laminations form part of the circuit.

[0130] Model 5 (not shown) is similar to the arrangement of Model 4, but in which both laminations are connected to the circuit on one side of the transformer. This is in contrast to Model 4, which shows one set of laminations connected to the circuit on the primary side of the transformer, and the other lamination connected to the circuit on the secondary side of the transformer.

[0131] A problem often encountered in the prior art is that there is a limit to the size of the magnetic field that can be induced in a ferromagnetic core. This is because the core includes many microscopic regions called magnetic domains, and there are a fixed number of magnetic domains in a core of a given size. The magnetic field of each of these magnetic domains is randomly oriented until the current in the primary coil induces a magnetic field in the core, at which time the magnetic fields of the magnetic domains in the core become aligned. As the magnetic domains become more closely aligned, a stronger magnetic field is induced in the core. However, this means that there is a limit to the size of the magnetic field that can be formed around the core, and this maximum value corresponds to a state where the magnetic domains of the core are fully aligned. At this point, any further increase in the number of turns of the primary coil will not result in an increase in the strength of the magnetic field generated around the core, which means that no additional power will be transferred to the secondary coil. At this point, the ferromagnetic core is considered to be saturated.

[0132] In order to solve the saturation problem and transmit additional power, a larger ferromagnetic core can be used. This provides a greater number of magnetic domains, which allows a stronger magnetic field to be induced before saturation is reached. However, for this reason, prior art transformers tend to be physically large.

[0133] It would therefore be desirable to develop a system by which the power transmitted through a transformer could be increased without requiring a larger ferromagnetic core to prevent core saturation.

[0134] By making the primary and secondary cables from capacitive cables, it may not be necessary to increase the frequency of the input AC current to increase the inductive reactance of the cables. It may also not be necessary to increase the number of turns of the coil. As a result, more power can be transmitted through the transformer without increasing the size of the ferromagnetic core. Therefore, the present invention allows the production of smaller transformers.

[0135] One of the benefits of the present invention using high frequency power transmission is that it allows smaller electrical components to be used. This is possible because the magnetic field used (such as that used in a transformer) grows and decays more times per second. For example, in aircraft, a frequency of 400 Hz is used. This allows components to be eight times smaller than when 50 Hz is used.

[0136] When the plane arrives at the gate, it usually needs to be connected to the airport's power supply. Assuming the airport's power frequency is 50Hz, a converter is required at both ends to convert it to 400Hz.

[0137] The converter works by receiving an AC input, converting the AC to DC, and then running the DC through a second stage of the converter, called an "inverter", which converts the DC to AC (but at a different frequency than the incoming AC). In a high frequency power distribution network, one advantage of the present invention is that a converter need not be provided at each gate. Instead, a network can be provided in which a single converter is provided at the airport and the power cables at each gate are connected to that converter.

[0138] In the present invention, there may 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 may be in opposite vector directions. Since the capacitance is much larger, the net capacitance increases. In the transformer of the present invention, the core laminations (layers or stacks) also act as capacitors. This enables both magnetic and electric fields to be utilized. There may be benefits here, such as for wireless charging.

[0139] The number of turns shown in each coil is the same in both Model 1 and Model 2. In Model 1, it can be thought of as comprising four wires arranged into two coils. The primary coil comprises two of these wires and the secondary coil comprises the other two.

[0140] In the primary coil of Model 1 (left), the red and green wires are connected in series, with capacitor C1 connected between them. Both wires are coiled around one of the cores to create the primary coil. However, in the secondary coil, the red and green wires are connected in parallel, with a capacitor between them as well. Just like the primary coil, the two wires of the secondary coil are coiled around one side of the core to create the secondary coil.

[0141] The result of having a primary coil in which two of the wires are connected in series and a secondary coil in which two of the wires are connected in parallel is that the primary coil is actually twice as long as the secondary coil (assuming all four wires are the same length). This means that the primary coil actually contains twice as many turns as the secondary coil (again, assuming all 4 wires have the same number of turns). The result of this 2:1 turns ratio between the primary and secondary coils is a 2:1 voltage ratio between the primary and secondary coils. Thus, Model 1 depicts a step-down transformer in which the voltage across the transformer is reduced by 50%.

[0142] Model 3 is essentially the inverse of Model 1. In this case, the two wires of the primary coil are connected in parallel, while the two wires of the secondary coil are connected in series. Therefore, Model 3 depicts a step-up transformer in which the voltage across the transformer is doubled.

[0143] In the present invention, different turns ratios between the two coils can be used, for example not 2:1 or 1:2. The fact that the voltage variation across the transformer is determined (ie the capacitance of each coil) does not affect this.

[0144] While the amount of capacitance in each coil may not affect the change in voltage across the transformer, this may serve another important purpose, which is to limit the flow of current. If the reactance of the coil is too low, then the current flowing through it will be too high and the wires will burn out. In a conventional transformer, this is solved by increasing the number of turns in each coil. However, if a capacitor is included, then it may not be necessary to add extra turns to increase the reactance. The capacitor will perform this role instead. If no extra turns are needed, then the coils can therefore be made shorter, which means that the transformer as a whole can be made smaller.

[0145] In prior art transformers, these transformers are typically configured to operate at a specific input voltage (e.g., 100 volts). Voltage is of course proportional to current (V=IR). Assuming the resistance is fixed (because the number of turns in the coil is fixed), if the transformer is operated with an input voltage of 100 volts, the current will increase to compensate, which may cause the wire to burn out. This may not be a problem for the present invention because, while it is equally impractical to modify the number of turns, the capacitance can be changed to make up for the difference. This can make it easier to change the voltage transmitted through the transformer than using a conventional transformer. This is what is called a dynamic arrangement in the present invention.

[0146] It should be noted that this does not change the voltage ratio between the coils (2:1, 5:1, etc.) This ratio is only affected by the number of turns in each of the respective primary and secondary coils.

[0147] In most embodiments, when the voltage is known, the required capacitance can be determined. The same applies to wireless charging of electric motors and electric vehicles. In the case of wireless charging, the transmitter can be considered to be similar to the setup of a transformer, but without the presence of ferromagnetic coils, i.e. two coils with a magnetic field between them. In this case, the absence of a core means that the energy transfer may not be as efficient as in a transformer, where the core is used to guide the magnetic field.

[0148] In the above case, the red and blue laminations represent the laminations electrically connected to the red and blue wires in the primary and secondary coils, respectively. Because the laminations are dielectrically isolated from each other by the insulating layer, the laminations act as capacitors. Therefore, the energy in the eddy currents generated in the laminations can be utilized and used for energy transmitted through the transformer. In the transformer of the prior art, these eddy currents only cause energy loss.

[0149] Model 5 is similar to the setup of Mode 4, but where the two sets of laminations are aligned to wire in the same coil, rather than in opposing coils.

[0150] Capacitive transformers and conventional transformers

[0151] The invention is illustrated by disassembling and reconfiguring the primary / secondary windings of a conventional transformer using capacitive windings.

[0152] Conventional transformers have the following characteristics:

[0153]

[0154]

[0155] A conventional transformer is operated over a range of frequencies to demonstrate the characteristics of the turns ratio and the opportunities that arise when a CTS connection is incorporated in the windings.

[0156] In a conventional transformer, two primary windings are connected in parallel (P1 / / P2), followed by two secondary windings connected in series (S1+S2). This setup sets the turns ratio in the transformer windings to 1:2 (N p :N s ), so a step-up transformer topology is established, and Figure 7 A conventional transformer equivalent circuit is schematically shown in FIG.

[0157] The transformer operation was tested experimentally (connected to a 66Ω load). During the experiment, when Vp was increased to 115 volts at 50Hz, the transformer core saturated due to the primary current exceeding the magnetic field strength threshold for a given core. When increasing the supply frequency, for a given primary voltage and turns ratio, the secondary voltage undergoes minimal change and the transformer winding relationships remain applicable, i.e., continue to operate as a step-up transformer. Operational performance is shown in Figure 8 shown.

[0158] However, when converting the winding topology from a conventional transformer to the transformer of the present invention, i.e., introducing a capacitive element into the transformer winding as explained in the present invention, the turns ratio relationship is no longer the main factor defining the winding parameters such as voltage and current. Instead, the reactance (capacitive and inductive) of the winding and its accompanying parameters (such as frequency) will contribute to the mode / topology (buck, isolation or boost) of the transformer.

[0159] We designed and manufactured a transformer of the present invention with the same rating (and number of turns) as the conventional transformer described above, but using the capacitive winding of the present invention in both windings. The primary winding and the secondary winding are connected in series and in parallel, respectively, to establish a step-down transformer according to the transformer turns ratio rule.

[0160] Fig. 9 The equivalent circuit of the transformer (step-down) according to the invention incorporating capacitive windings on both windings is shown.

[0161] Capacitive reactance is incorporated into the primary winding, which limits the current used to excite the core (i.e., to generate the magnetic flux connecting the primary and secondary windings). Therefore, compared to conventional transformers, for example at 50 Hz, the primary voltage can be increased beyond the point where a current that saturates the current will be generated. On the other hand, since the primary current is reduced, the reduced current reduces the voltage induced in the secondary winding.

[0162] Furthermore, due to the presence of inductive and capacitive elements in the windings, the resulting reactance will vary with changes in the power supply frequency. One of the changes observed is a variable voltage ratio (Vp:Vs) that is independent of the winding turns ratio. At approximately 100Hz, the transformer operates in step-down mode. As the frequency increases, the inductive reactance increases, while the capacitive reactance decreases.

[0163] Conversely, for the same primary voltage, the voltage induced in the secondary winding increases due to the change in current distribution between the inductive and capacitive elements. At approximately 600 Hz, the reactance has been substantially minimized (as shown by the increase in power factor) and the transformer now behaves as an isolation transformer. Further increases in frequency will result in an increase in X L Greater than X C and changes the operation to a step-up transformer. Minimization of reactance in the windings allows for greater power capacity.

[0164] As shown in the above operation, when the frequency is below 600Hz, the transformer operates in CTS mode (X L <X C ), but when the frequency reaches and increases above 600Hz, the transformer reverts to normal deformation because X L It is the main reactance in the winding (X L >X C ).

[0165] The increase in supply frequency enables the reactive elements in the windings to charge and discharge at a faster rate than the conventional 50Hz, which enables higher power to be transmitted in both conventional and CTS models while avoiding saturation. This also demonstrates the compatibility of the CTS connection for higher frequency operation. However, it should be noted that an additional increase in frequency beyond a certain threshold will increase eddy currents and result in power losses in the core (core frequency compatibility becomes critical).

[0166] After manufacturing the transformer of the present invention, we tested it to compare it with a conventional version. Fig.10 shown.

[0167] One of the main design results is that the size of the CTS transformer core is reduced while transmitting the same power as a conventional transformer relying on a large core - see Fig.11 , Fig.11 A conventional transformer and an equivalent transformer constructed in accordance with the present invention are shown side by side.

[0168] Example 2 - Motor

[0169] Figure 1 and Figure 2 A schematic diagram of a motor including a capacitive winding according to the present invention is shown ( Figure 1 The general winding and Figure 2 The star connection in the figure).

[0170] Fig.14 The equivalent circuit of a conventional induction motor with conventional windings is shown:

[0171] V1=Input voltage (source voltage)

[0172] R1 = resistance of stator winding, Ω

[0173] X1 = stator leakage reactance (winding), Ω

[0174] Xm=magnetizing reactance of stator, Ω

[0175] Rc = core losses (hysteresis and eddy currents)

[0176] I1, Is = stator current, A

[0177] I0=magnetizing current, A

[0178] E1 = stator induced electromotive force

[0179] S = Slip

[0180] E2 = electromotive force induced in the rotor

[0181] T = motor torque, Nm

[0182] I2 = rotor current, A

[0183] X2=rotor circuit reactance, Ω

[0184] R2=rotor circuit resistance, Ω

[0185] Fig.15 and Fig.16 An equivalent circuit diagram representing a motor having a capacitive winding of the present invention is shown:

[0186] V1=Input voltage (source voltage)

[0187] R1 = resistance of stator winding, Ω

[0188] Xcts = stator CTS reactance (winding), Ω

[0189] Xm=magnetizing reactance of stator, Ω

[0190] Rc = core losses (hysteresis and eddy currents)

[0191] I1, Is = stator current, A

[0192] I0=magnetizing current, A

[0193] E1 = stator induced electromotive force

[0194] S = Slip

[0195] E2 = electromotive force induced in the rotor

[0196] T = motor torque, Nm

[0197] I2 = rotor current, A

[0198] X2=rotor circuit reactance, Ω

[0199] R2=rotor circuit resistance, Ω

[0200] Example 3 - Wireless Charging Pad

[0201] We use capacitive cables and high frequency AC in the feed cable and primary electric vehicle (EV) wireless charging pad (also known as charging pad). In this example, when in self-compensation mode, the CTS cable is led out from the inverter, wound to form a coil and returned to the inverter to complete the circuit, i.e., the cable is an uninterrupted continuous loop passing through the coil and returning to the inverter. Therefore, in essence, the coiled cable (i.e., the primary pad) will contain capacitive characteristics and inductive characteristics (i.e., hybrid wireless power transfer (WPT) due to physical elements representing inductors (coils) and capacitors (CTS terminals)).

[0202] The CTS capacitors compensate for both the coil and cable reactance.

[0203] exist Fig.17 A plate incorporating a coil of the invention is schematically shown in FIG.

[0204] In section 1 there is capacitive coupling between a first cable connected to the power supply and a second cable (not connected to the power supply). The pair of cables continue to the pad.

[0205] In section 2 , the mat comprises two cables which are also capacitively coupled and wound into a mat coil and then exit towards section 3 .

[0206] In section 3, the cable leaving the pad remains capacitively coupled, and the second cable is connected back to the other side of the power supply, but the first cable is not, thus providing a capacitive winding in the coil of the charging pad.

[0207] Example 4

[0208] In the development of the transformer described in Example 1, Fig.18 In another transformer design of the present invention, schematically shown in , we use high frequency CTS cable both as feed cable and for the windings.

[0209] Therefore, capacitive conductors using insulated conductors or wires or cables are used in the electric machine in the form of windings.

Claims

1. An electric machine, comprising a conductor wound into an electromagnetic coil, wherein: The conductor is a capacitive conductor which is represented by a capacitor in the circuit diagram.

2. An electric machine, comprising a capacitive winding, wherein the capacitive winding is a capacitive wire wound into a coil, wherein: The capacitive wire is any wire that has capacitive coupling within its conductors / conductive elements and is represented in circuit diagrams by capacitors.

3. The motor according to claim 1 or 2, wherein: The capacitive conductor or capacitive wire comprises two conductors coupled to each other via capacitive coupling.

4. The motor according to claim 3, wherein: The two conductors are electrically isolated from each other by a dielectric material, which together with the two conductors form the capacitive coupling.

5. An electric machine as claimed in any preceding claim, comprising an electric conductor in the form of a coil, spiral or helix.

6. An electric machine according to claim 5, comprising two or more conductors wound in the form of a coil, spiral or helix.

7. An electric machine according to any one of the preceding claims, wherein: The electric machine is a transformer (optionally comprising a ferromagnetic core), a motor, a generator, a solenoid, an electromagnet, an antenna, a stove, a heater, a (wireless) charger or a dynamo.

8. The transformer according to claim 7, wherein: The transformer further comprises a capacitor connected to the primary coil and / or a capacitor integrated with the primary coil.

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

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

12. The motor according to claim 7.

13. The generator according to claim 7.

14. The electromagnet according to claim 7.

15. The antenna according to claim 7.

16. The furnace of claim 7.

17. The heater according to claim 7.

18. The charger according to claim 7.

19. The wireless charger according to claim 7.

20. The solenoid of claim 7.

21. A DC generator according to claim 7.

22. A method of manufacturing an electric machine according to any one of the preceding claims, comprising: providing a cable or a wire or a conductor, said cable or said wire or said conductor comprising two conductors separated by a dielectric material, forming a capacitive connection between the two conductors, and The cable, the wire or the conductor is wound into a coil or otherwise made into a coil.

23. An electric machine comprising a capacitive winding.

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

25. The electric machine according to claim 23, wherein The capacitive winding comprises a conductor, within which a capacitive coupling exists, the conductor being represented in the circuit diagram by a capacitor.

26. The electric machine according to claim 25, wherein The conductor of the capacitive winding includes two conductors coupled to each other via capacitive coupling.

27. An electric machine according to claim 25 or 26, wherein: The conductors include two conductors, such as conductive wires, electrically isolated from each other by a dielectric material, the dielectric material and the conductive wires together forming the capacitive coupling.

28. An electric machine according to any one of claims 23 to 27, wherein The capacitive winding comprises an electrical conductor in the form of a coil, spiral or helix.

29. An electric machine according to claim 28, comprising two or more capacitive windings, each capacitive winding comprising one or more electrical conductors wound in the form of a coil, spiral or helix.

Images