A multi-phase winding, a stator assembly and a motor

Abstract

The present invention discloses a multi-phase winding, a stator assembly and a motor. Each phase winding is formed by connecting one or more unit windings, and each unit winding includes: a double-layer conductor module at the head end, a plurality of middle double-layer conductor modules and a single-layer conductor module at the end, and an end conductor connecting each module. The upper and lower conductors of all double-layer conductor modules are connected by the end conductors to form upper and lower wave-shaped semi-windings. The upper and lower wave-shaped semi-windings are connected in series by the single-layer conductor at the end, and all conductors are insulated. The multi-phase winding has a special electromagnetic effect in an alternating magnetic field. The stator assembly and the permanent magnet rotor form a motor. Under the excitation of an alternating magnetic field containing a high-frequency pulse component, a special electromagnetic effect is excited in the double-layer conductor module, and the electromagnetic energy entering the conductor during the electromagnetic energy transmission process is greatly reduced. The winding of the present invention has the advantages of small leakage reactance and small heat loss, which is of great significance to improving the electromechanical energy conversion efficiency and the power density of the motor.

Description

Technical Field

[0001] The present invention relates to the field of electromechanical energy conversion, in particular to the field of electric motors, and specifically to a multi-phase winding, a stator assembly thereof and a motor. Background Art

[0002] Conductors are carriers of electrical energy. In the power transmission and distribution system of the electric power system, resistance loss leads to reduced efficiency of electrical energy transmission. In the field of motors, wires are carriers of energy changes (mechanical energy-electrical energy). The greater the resistance loss of the wires, the lower the power generation efficiency, the greater the heat generated inside the motor, and the larger the volume of the corresponding heat dissipation material.

[0003] The losses of the motor mainly include the resistance heating loss when the winding transmits the current, the core loss caused by the change of the magnetic field in the magnetic circuit, and other stray losses. The pursuit of low loss and high efficiency is the long-term goal of the development of the motor (generator, motor). To this end, researchers have carried out many studies, including new structures that increase magnetic load and electric load (such as transverse flux motors), optimize the magnetic field distribution inside the motor, use low-loss conductive materials and magnetic conductive materials, improve the power factor of the motor, etc.

[0004] In essence, the size of the motor is closely related to the heat loss of the motor. The loss is composed of the core loss and the copper loss of the armature winding. The power (torque) density of the motor is related to the air gap magnetic density of the motor and the heat loss of the motor. The heating of the motor current carrier (coil conductor) and the heat dissipation of the motor have an important influence on the power density of the motor. Improving the power density of the motor is of great significance to the miniaturization of equipment, while reducing the loss of the motor can improve the power density of the motor on the one hand, and greatly improve the energy utilization rate on the other hand. Therefore, the high-efficiency and low-loss technology of the motor has always been a research hotspot in the field of motors. However, the current structure of conventional motors or generators seriously restricts its improvement in efficiency improvement and miniaturization. Therefore, developing a new low-loss motor winding technology to effectively improve the efficiency of electromechanical energy conversion in the power generation system has important practical significance for improving the power density of the motor and miniaturization of equipment, and will have a huge driving effect on the development of the industrial and energy fields. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a new type of multi-phase winding, stator assembly and corresponding motor. The unit winding constituting the multi-phase winding adopts a special double-layer conductor structure, including the multi-phase winding and the stator assembly of the auxiliary excitation winding. High-frequency pulse current is passed to modulate the magnetic field of the motor, stimulate the electromagnetic effect inside the double-layer conductor, make full use of the coupling relationship between the electrical, magnetic and mechanical energy inside the motor, improve the electromagnetic energy of the stator assembly and the winding, improve the energy conversion rate of the motor, and reduce conductor losses.

[0006] The above-mentioned object of the present invention is achieved by the following technical solutions:

[0007] A multi-phase winding arranged on the stator of a motor, each phase winding is formed by connecting one or more unit windings, wherein:

[0008] Each of the unit windings comprises: a head-end module, a plurality of intermediate modules and a terminal module and an end conductor connecting the modules, wherein the intermediate module is located between the head-end module and the terminal module;

[0009] The head-end module and the middle module are both double-layer conductor modules, which are composed of an upper conductor and a lower conductor arranged in the same stator slot; the terminal module is a single-layer conductor module, which is composed of a terminal single-layer conductor arranged in a terminal stator slot;

[0010] The upper conductors in all double-layer conductor modules are connected through the end conductors to form an upper wavy half-winding, and the lower conductors in all double-layer conductor modules are connected through the end conductors to form a lower wavy half-winding. The upper wavy half-winding and the lower wavy half-winding are connected in series through the end single-layer conductor; all the conductors are covered with insulation.

[0011] In a specific example of the present invention, in the same stator slot, the upper and lower conductors in the same double-layer conductor module are stacked up and down along the slot depth direction, and the projections of the upper and lower conductors on the slot bottom surface at least partially overlap.

[0012] In a specific example of the present invention, each phase winding is formed by connecting a plurality of unit windings, and the plurality of unit windings are arranged in the same double-layer space to form a double-layer composite winding.

[0013] In a specific example of the present invention, among the multiple unit windings constituting the double-layer composite winding, there is at least one unit winding with non-equidistant spacing.

[0014] In a specific example of the present invention, the plurality of unit windings constituting the double-layer composite winding include an equally spaced unit winding and an even number of non-equally spaced unit windings.

[0015] The invention also discloses a stator assembly, comprising the multi-phase winding.

[0016] The present invention also discloses a motor, comprising the above-mentioned stator assembly and a permanent magnet rotor. In a single unit winding, two adjacent conductor modules correspond to two adjacent magnets of the rotor respectively, and the magnets on the rotor are arranged in sequence in alternating north and south poles.

[0017] In a specific example of the present invention, in the motor, permanent magnets with the same width are sequentially mounted on the permanent magnet rotor, and the gaps between two adjacent magnets are equal, and the gaps are equivalent to the width of the stator slots.

[0018] The invention also discloses another stator assembly, comprising the multi-phase winding and an auxiliary excitation winding.

[0019] The present invention also discloses another motor, comprising the above-mentioned another stator assembly, a permanent magnet rotor and a magnetic field modulation control module, wherein the modulation control module is used for regulating the excitation pulse current applied to the auxiliary excitation winding.

[0020] In the present invention, the double-layer conductor module constituting the unit winding has at least partially overlapped upper and lower conductors in the same stator slot, forming a special internal electric field and capacitance effect. By reasonably designing the distance between the rotor magnetic steels (gap) and the width of the stator slot, or by setting an auxiliary winding and controlling the pulse current excitation, a high-frequency potential pulse is induced on the double-layer conductor module, exciting the traveling wave current on the conductor, and exciting the charge "gathering-dissipation" oscillation pattern on the upper and lower conductors of the double-layer conductor module, further ensuring and intensifying the internal capacitance effect between the double-layer conductors, so that the surface tangential electric field of the upper and lower conductors on the inner side of the double-layer conductor is greatly reduced, which is smaller than the surface tangential electric field of a general single conductor or parallel transmission line. The electromagnetic energy entering the conductor from the surface of the conductor is greatly reduced, thereby greatly reducing the internal heat loss of the conductor in the slot and improving the energy transfer efficiency.

[0021] In addition, all conductors that make up the unit winding are insulated, and the two sides of the winding conductor are directly in contact with the two sides of the slot through insulation, which greatly improves the heat dissipation capacity of the winding conductor; the conductors in the same slot are insulated from each other, and parasitic capacitance is formed between the upper and lower conductors. Since the distance between the upper and lower conductors is close, the corresponding capacitance can compensate for the inductance of the winding conductor and improve the power factor of the generator; moreover, in each unit winding that makes up each phase winding, the distance between the end conductors on both sides of the stator is short, so the winding conductor has a small resistance and leakage reactance. In the stator slot where each double-layer conductor module is located, the current flowing through the upper and lower conductors is in the same direction, and the conductors of each layer in the same unit winding are in a series relationship, and the conductors of each layer are in a series relationship, so the unit winding voltage is easy to adjust.

[0022] Therefore, the winding, stator assembly and motor of the present invention fully utilize the coupling relationship between the electrical, magnetic and mechanical energy inside the motor, improve the energy conversion rate of the motor, reduce losses, and efficiently convert electrical energy into mechanical energy through magnetic field energy, or convert mechanical energy into electrical energy with high efficiency and low loss.

[0023] Compared with the prior art, the present invention has the following beneficial technical effects:

[0024] (1) The winding voltage of the present invention is easy to adjust and can be easily matched with a multi-pole motor, and is particularly suitable for use as a stator component of a multi-pole multi-phase motor;

[0025] (2) The winding end of the present invention is small in size, which saves materials and reduces winding leakage reactance and resistance.

[0026] (3) The conductor of the winding of the present invention has a large contact area with the stator slot, a large heat dissipation area, and a good heat dissipation effect; it is suitable for hard winding production, and the winding of the present invention rarely has continuous bending in the same direction during the production process.

[0027] (4) The winding of the present invention includes a double-layer conductor module, which has a special capacitance effect. On the one hand, it is beneficial to compensate for the inductance of the motor winding and improve the motor power factor. On the other hand, it greatly reduces the electromagnetic energy entering the conductor and the heat loss inside the conductor, and the electromechanical energy conversion efficiency is high.

[0028] (5) The winding structure of the present invention is compact and easy to manufacture. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the structure of a typical unit winding.

[0030] Figure 2a A typical arrangement of a double-layer composite winding is given.

[0031] Figure 2b To constitute Figure 2a The schematic diagram of the arrangement of each unit winding in the double-layer composite winding is shown.

[0032] Figure 3 Another typical arrangement of a double-layer composite winding is given.

[0033] Figure 4a It is the electric field model formed between the upper and lower conductors in the double-layer conductor module.

[0034] Figure 4b Schematic diagram of the magnetic field (magnetic density wave) generated by the permanent magnet rotor in the air gap.

[0035] Figure 4c Schematic diagram of two types of potential waveforms induced by the permanent magnet rotor on the conductor.

[0036] Figure 4d Schematic diagram of the synthetic potential waveform generated by the permanent magnet rotor magnetic field on the conductor.

[0037] Figure 4e Schematic diagram of the charge distribution on the conductor surface in a double-layer conductor module at a certain moment.

[0038] Figure 5a Schematic diagram of the magnetic field distribution around a single conductor when current flows through it.

[0039] Figure 5b Schematic diagram of the magnetic field distribution around two conductors when current flows through them.

[0040] Figure 6 Schematic diagram of the electric field, magnetic field and Poynting vector on the surface of a single conductor and its surroundings.

[0041] Figure 7 Schematic diagram of the distribution of conductor surface charge and surrounding magnetic field in a double-layer conductor module. In the figure, ▲ and ▼ represent the charge and current direction, · and ╳ represent the magnetic field direction, and S represents the Poynting vector.

[0042] Figure 8 A schematic diagram of a motor system with an auxiliary excitation winding and excitation control.

[0043] Fig. 9 It is a schematic diagram of the induced potential generated on the conductor by the permanent magnet magnetic field and the pulse magnetic field generated by the auxiliary excitation current. DETAILED DESCRIPTION

[0044] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings and examples, so as to more clearly understand the technical content of the present invention. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0045] Embodiment 1

[0046] In a specific embodiment of the present invention, a multi-phase winding is provided on a stator, each phase of which is formed by one or more unit windings connected in series or in parallel.

[0047] Each unit winding, such as Figure 1 As shown, it includes: a head end module 11, a plurality of intermediate modules 12 and an end module 13 and an end conductor connecting the modules, wherein the intermediate module 12 is located between the head end module 11 and the end module 13, wherein the head end module 11 and the intermediate module 12 are both double-layer conductor modules, the double-layer conductor modules are composed of an upper conductor and a lower conductor arranged in the same stator slot, and the end module 13 is a single-layer conductor module, the single-layer conductor module is composed of a single-layer conductor (also called a terminal single-layer conductor) arranged in the terminal stator slot; the upper conductors in all double-layer conductor modules pass through the end The conductors are connected to form an upper wavy semi-winding 14, which moves forward like a wave in the winding direction. The lower conductors in all double-layer conductor modules are connected through the end conductors to form a lower wavy semi-winding 15, which moves forward like a wave in the winding direction. The upper wavy semi-winding 14 and the lower wavy semi-winding 15 are connected in series through the end single-layer conductor (the end where the end single-layer conductor is located is also called the connection end 16); all conductors (including all upper conductors, lower conductors, end single-layer conductors and end conductors) are covered with insulation.

[0048] The connection method of the above unit windings is specifically described as follows:

[0049] Starting from the head end module 11, the upper conductors in all double-layer conductor modules (i.e., the head end module 11 and all the intermediate modules 12) are connected in sequence through the end conductors, and the incoming lines are connected to the single-layer conductor modules (i.e., the end module 13). At the same time, the outgoing lines of the single-layer conductor modules are connected to the lower conductors in the adjacent double-layer conductor modules, and the lower conductors in all the double-layer conductor modules are connected in turn through the end conductors, and finally connected to the lower conductor of the head end module 11, that is, the starting conductor and the outgoing conductor of each unit winding are the upper conductor and the lower conductor of the head end module 11, respectively, and the upper and lower conductors in the head end module 11 correspond to the unit windings, respectively. The input port and output port of the winding; or, the lower conductor in the head-end module 11 may correspond to the input port of the unit winding, and the upper conductor may correspond to the output port of the unit winding, that is: starting from the head-end module 11, the lower conductors in all double-layer conductor modules (that is, the head-end module 11 and all intermediate modules 12) are connected in sequence through the end conductors, and the incoming lines are connected to the single-layer conductor modules (that is, the end module 13). At the same time, the outgoing lines of the single-layer conductor modules are connected to the upper conductors in the adjacent double-layer conductor modules, and are connected in reverse order to the upper conductors in all double-layer conductor modules through the end conductors, and finally connected to the upper conductor of the head-end module 11.

[0050] When in use, current is introduced from a layer of conductors (upper or lower conductors) of the head-end module 11 (this is the input port of the unit winding), passes through the upper (or lower) conductors of all the intermediate modules 12 in sequence, reaches the end module 13 (single-layer conductor), and then passes through the lower (or upper) conductors of all the intermediate modules 12 in reverse order, and finally the current flows out from another layer of conductors (lower or upper conductors) of the head-end module 11 (this is the output port of the unit winding).

[0051] It can be found that in a unit winding, the direction of the current flowing through the upper and lower conductors of each double-layer conductor module located in the same stator slot is consistent, the conductors in each slot of each layer are in series, and the upper and lower conductors are in series with the single-layer conductor. The potential of the unit winding is related to the number of double-layer conductor modules possessed by the winding, and it is very convenient to adjust the voltage as needed; moreover, the starting conductor (input port) and the end conductor (output port) of each unit winding are both located in the same slot corresponding to the head-end module 11, so that the distance between the end conductors of the unit winding on both sides of the stator is short, and the winding leakage reactance is small; in addition, since the stator slot is arranged on the inner surface of the circumference of the stator core along the axial direction of the stator core, when the conductor in the slot is coated with insulating material, the two sides of the conductor in the slot are in direct contact with the two sides of the stator slot through the insulating material, and the heat dissipation effect of the conductor is very good.

[0052] In each of the above-mentioned unit windings, in the same stator slot, the upper and lower conductors in the same double-layer conductor module are stacked up and down along the slot depth direction (i.e., the radial direction of the stator core), and the projections of the upper and lower conductors on the bottom surface of the slot completely overlap or mostly overlap (i.e., at least partially overlap). Moreover, in the double-layer conductor module, the upper and lower conductors in the same stator slot are insulated from each other, and parasitic capacitance is formed between the upper and lower conductors. Since there is an electric potential transmitted from the module connected to the upper and lower conductors, under the action of the electric field and the magnetic field, there is a large amount of free charge in the area between the upper conductor and the lower conductor, forming a special capacitance and electric field.

[0053] Each of the above-mentioned unit windings can be wound by a single conductor (generally a softer wire), or can be formed by welding the conductors in each slot (generally a hard conductor material) at the ends. In this way, in a stator slot, whether it is an upper conductor, a lower conductor or a single-layer conductor, they are all single conductors.

[0054] In the above-mentioned single unit winding, the number of stator slots spanned by each pair of adjacent modules (also called module spacing) may be the same (equal) or different (unequal).

[0055] For a single unit winding, if the spacing between modules is equal, it is called an equal-spacing unit winding; if the spacing between modules is unequal, it is called a non-equal-spacing unit winding.

[0056] For multiple unit windings, the structures of the unit windings with the same module spacing distribution are the same. Different starting positions are set for different unit windings. Multiple unit windings can be arranged in the same double-layer space to form a double-layer composite winding. In this case, the conductors in the slots of different unit windings are in the same double-layer space, but the end conductors will overlap in space. The structures of the unit windings with different module spacing distributions are different. By designing the adjacent module spacings in different unit windings and the starting positions of the unit windings, multiple unit windings with different structures can be arranged in the same double-layer space to form a double-layer composite winding. In this case, the end conductors belonging to different unit windings are in the same double-layer space, which is more compact in structure.

[0057] As an example, Figure 2a and Figure 2b A typical double-layer composite winding and the arrangement of multiple unit windings constituting the composite winding are given respectively. Figure 2a and Figure 2bIn the figure, the double-layer composite winding is composed of three unit windings 24, 25, and 26 connected in series, wherein the first unit winding 25 and the third unit winding 26 are both non-equally spaced unit windings, and the second unit winding 24 is an equally spaced unit winding. The design of the module spacing and starting position of the three unit windings can make each module be placed in a different stator slot, so that the three unit windings with different structures can be arranged in the same double-layer space (composed of an upper wavy half winding 21 and a lower wavy half winding 22) to form a double-layer composite winding 23, which has a compact structure, saves winding conductor materials, and reduces the leakage reactance of the winding at the end, the resistance of the winding and the loss caused by it.

[0058] As an example, Figure 3 Another typical structural schematic diagram of a double-layer composite winding is given. Figure 3 In the figure, the double-layer composite winding is composed of three unit windings connected (in series or in parallel), and the spacing between each module in the three unit windings is equal. Among them, 61 is the same stator tooth, and 62 is the same stator slot. 63 is the upper conductor of the first unit winding head module, 64 is the lower conductor of the first unit winding head module, 65 is the conductor of the first unit winding end module (single layer), and 65 refers to the same conductor. 66 is the upper conductor of the second unit winding head module, 67 is the lower conductor of the second unit winding head module, 68 is the conductor of the second unit winding end module (single layer), and 68 refers to the same conductor. 69 is the upper conductor of the third unit winding head module, 70 is the lower conductor of the third unit winding head module, 71 is the conductor of the third unit winding end module (single layer), and 71 refers to the same conductor.

[0059] Figure 3 The figure shows a schematic diagram of a double-layer composite winding composed of three identical equally spaced unit windings. The upper and lower conductors are spread out on the same plane, that is, the three unit windings are arranged in the same double-layer space to form a double-layer composite winding. However, due to the overlap between the end conductors of each unit winding, there are some requirements for the manufacturing process.

[0060] In comparison, Figure 2a and Figure 2b The double-layer composite winding shown in has more advantages in manufacturing. That is, when there is at least one non-equidistant unit winding, the end conductors of multiple unit windings arranged in the same double-layer space do not overlap, which is more convenient in the manufacturing process.

[0061] Multiple unit windings in the same or different double-layer spaces are connected in series or in parallel to form a multi-phase winding of the motor.

[0062] Will Figure 2a , Figure 2b or Figure 3The double-layer composite winding shown is used as a stator winding, which is assembled on the stator core to form a stator assembly. Each conductor module (in upper and lower layers) is placed in a slot, and each pair of adjacent conductor modules in each unit winding corresponds to two adjacent magnets of the rotor. Further, the above-mentioned stator assembly and permanent magnet rotor can form a motor system. For a permanent magnet motor, magnets are sequentially assembled on the permanent magnet rotor to form a distribution of N, S, N, S (that is, each magnet is arranged in sequence in the order of alternating north and south poles). In the gap area between the magnets, the magnetic field in the air gap appears as an alternating magnetic field (such as changing from an N-direction magnetic field to an S-direction magnetic field).

[0063] In the above motor system, permanent magnets of the same width are sequentially mounted on the permanent magnet rotor, and the gaps between adjacent magnets are equal, and the number of stator slots is an integer multiple M of the number of magnets contained in the permanent magnet rotor. When the gap between the rotor magnets is equivalent to the width of the stator slot, the alternating degree of the magnetic field will also increase, and the potential induced on the unit winding and the double-layer conductor module will contain high-frequency pulse components, and the frequency contained in the pulse can be set according to the magnet spacing and the stator slot size.

[0064] The present invention also discloses a motor, comprising the above-mentioned stator assembly and a permanent magnet rotor, wherein in each of the unit windings, two adjacent conductor modules correspond to two adjacent magnets of the rotor respectively, and the magnets on the rotor are arranged in sequence in alternating north and south poles.

[0065] For better understanding, the principles of the above windings, stator components and motors will be described below.

[0066] Figure 4a The electric field model formed between the upper and lower conductors of the double-layer conductor module in the present invention is given. Figure 4a In the figure, ab is the upper conductor, cd is the lower conductor, J1 and J2 are the current per unit length in the upper and lower conductors, ε1 and ε2 are the potential per unit length in the upper and lower conductors, z represents the coordinate of a certain position in the axial direction, and △ represents a position interval in the axial direction z. Figure 4a In the figure, the current flowing through the upper and lower conductors has the same direction, the upper and lower conductors form a series connection, the instantaneous values ​​of the upper current input port (end a) and the lower current output port (end d) are the same, and the currents at ends b and c are equal.

[0067] The permanent magnets are distributed alternately in N and S on the rotor. Figure 4b A schematic diagram of the magnetic field (magnetic flux density wave) generated by the permanent magnet rotor in the air gap is given. This schematic diagram is based on the assumption that the stator surface is smooth (no slots) and the magnetic potential distribution generated by the magnetic steel is sinusoidal. Figure 4b It can be seen that in the axial direction of the stator and rotor, the air gap flux distribution is basically the same; in the radial direction of the rotor, the magnetic flux distribution is approximately a sine wave.

[0068] In fact, the size of permanent magnets (especially the magnet gap) and the size of stator slots have an important influence on the magnetic flux density distribution. For example, when the rotor magnet spacing is equal to the stator slot width, the alternating degree of the magnetic field at the slot (conductor) will also increase when the magnetic poles alternate during the movement of the rotor magnets. The potential induced by the permanent magnet magnetic field in the motor on the conductor of the double-layer conductor module will contain high-frequency pulse components, such as Figure 4c As shown, it is obviously different from the approximately sinusoidal induced potential generated by the permanent magnet magnetic field in a normal motor. Figure 4c In the figure, the dotted line is the induced potential on the conductor when the stator slot is not considered (assuming that the stator surface is smooth and has no slots), which is approximately a sine wave. The solid line is the pulse potential added to the conductor when the slot width is equivalent to the gap between the magnetic poles. This pulse potential contains a higher frequency component. Figure 4d It is the synthetic potential waveform generated on the conductor by the permanent magnet rotor magnetic field (the slot width is equivalent to the gap between the magnetic poles).

[0069] Due to the capacitive effect between the upper and lower conductors, the high-frequency pulse potential induced by the magnetic field on the conductor also acts on both ends of the double-layer conductor, corresponding to the end positions of the axial magnetic field, making the charge distribution on the double-layer conductor capacitor seriously uneven. The charge in the double-layer conductor shows a "rapid accumulation-dissipation" phenomenon, and the current in the conductor of the double-layer conductor module along the axis z direction is a traveling wave (see the attached file for the specific analysis process). The charge distribution diagram on the conductor surface of the double-layer conductor module at a certain moment is as follows: Figure 4e shown. Figure 4e In the double-layer conductor module, there is an oscillating pattern of charge alternation on the conductor surface.

[0070] When the double-layer conductor module passes current, there is a magnetic field generated by the current around the conductor. Figure 5a A schematic diagram of the magnetic field distribution around a single wire (conductor) when current flows through it is given. Figure 5b A schematic diagram of the magnetic field distribution around a double-wire (conductor) when current flows through it is given. It can be seen that the inside of the double-layer conductor module is an area where the electric field and the magnetic field act together. Under the influence of the magnetic field, the capacitance between the upper and lower conductors of the double-layer conductor module is not only related to the shape and size of the conductors, the insulating material of the conductors, and the gap between the conductors, but also to the magnetic field distribution between the conductors.

[0071] Figure 6A schematic diagram of the electric field, magnetic field and Poynting vector on and around the conductor surface at a certain moment when a single conductor is flowing with current is given. The Poynting vector S is defined as: S = E × H, where E is the electric field intensity and H is the magnetic induction intensity. In the electromagnetic field, when the electric field and magnetic field are determined, the Poynting vector S can be used to express the power density (or energy flow density) of each point in the field and explain the loss and transmission phenomenon of electromagnetic energy. In the case of wires transmitting electrical energy, when the Poynting vector S is used to describe energy, the energy entering the conductor is not used to transmit energy, but is the energy consumed by the conductor.

[0072] The magnetic lines of force generated by the current in a single conductor are concentric circles with the intersection of the axis and the cross section as the center. Obviously, the deeper the Poynting vector S goes into the conductor, the smaller its value becomes, indicating that the energy gradually disappears. Since the conductor has resistance, it also consumes energy. Figure 6 The Poynting vector S outside the conductor is slightly inclined, and part of the energy flows into the conductor to compensate for the loss; only around an ideal (complete) conductor or superconductor, when the conductor does not consume energy, the Poynting vector S is completely parallel to the conductor surface.

[0073] Figure 7 A schematic diagram of the conductor surface charge and surrounding magnetic field distribution in a double-layer conductor module is given. Figure 7 Double conductor refers to a double-layer conductor module. Figure 7 In the figure, the current on the conductor in the double-layer conductor module is a traveling wave along the axis z direction, and the charge on the conductor surface is unevenly distributed along the conductor axis direction (z). At a certain position (z), the charge quantity of the upper and lower conductors is the same but the sign is opposite, and the charge quantity changes approximately as a sine function. The electric field on the conductor surface is mainly in the normal direction, and the tangential direction is very small. Since the current on the conductor is a traveling wave, the distribution of the magnetic field generated around the conductor in the axial direction of the conductor is also an alternating magnetic field; in addition, since the upper and lower currents belonging to the same group (i.e., the same double-layer conductor module) have a phase difference of 180 degrees at the same position, the magnetic fields between the double-layer conductors (upper and lower conductors) are superimposed on each other. It can be seen that compared with a single conductor, the Poynting vector S entering the double-layer conductor module is very small, so its heat loss is much smaller than that of a general transmission line.

[0074] The following is the analysis process of the current traveling wave solution:

[0075] refer to Figure 4a The electric field model between the upper and lower conductors of the double-layer conductor module is given. Figure 4a In the equation, ab is the upper conductor, and cd is the lower conductor. z is the axial direction of the upper and lower conductors (it can also refer to the coordinates of a certain position in the axial direction), and △ represents a position interval in the axial direction. J1 and J2 are the current per unit length in the upper and lower conductors, respectively, and ε1 and ε2 are the potential per unit length in the upper and lower conductors, respectively. Figure 4aIn the figure, the current flowing through the upper and lower conductors has the same direction, the upper and lower conductors form a series connection, the instantaneous values ​​of the upper current input port (end a) and the lower current output port (end d) are the same, and the currents at ends b and c are equal.

[0076] For the convenience of analysis, the influence of the magnetic field on the capacitor is equivalent to the correction of the capacitance value, and the current behavior on the upper and lower conductors of the double-layer conductor module complies with the "wave equation".

[0077] Suppose the charge per unit length in the double-layer conductor is Q, the capacitance per unit length is C0, the induced potential per unit length on the conductor due to the external alternating magnetic field is ε, and the current, resistance and reactance per unit length of the conductor are J, R, and L respectively.

[0078] The direction of the current is consistent with the direction of the potential according to the definition of the generator. The voltage difference between the upper and lower conductors (at the same axial coordinate z) is defined as the "transverse voltage", represented by U. The transverse voltage difference per unit length of the upper and lower conductors can be expressed as: Where α is a coefficient. Without loss of generality, J and ε are the current and induced potential per unit length of the upper conductor.

[0079] exist Figure 4a At the spatial position z shown in , there is a current equation:

[0080]

[0081] exist Figure 4a At the spatial position z shown in , the transverse voltage difference between the upper and lower layers of conductors is

[0082] U(z)=Q / C0 (2)

[0083] The relationship between the charge Q per unit length in a double-layer conductor and the current J flowing on the surface of the conductor is:

[0084]

[0085] Let C = αC0, C is the corrected capacitance value, the above formula (3) can be further written as formula (4)

[0086]

[0087] Taking partial derivatives of both sides of equation (4) with respect to time t, combined with the current equation (1), we get

[0088]

[0089] The wave conduction equation is obtained

[0090]

[0091] because R≠0. If the electric potential in the axial direction of the double-layer conductor changes greatly (such as the magnetic field at the end of the conductor changes greatly, which is approximately a pulse change), considering that the currents at ends a and d (and ends b and c) are equal, the current of the wave equation (5) has the following traveling wave solution form.

[0092] J(z,t)=Je j(kz+ωt+φ) (6)

[0093] Among them, k is the propagation coefficient; ω is the current angular frequency, and φ represents the current phase angle.

[0094] according to Figure 4a In the series model shown, the z-direction coordinate is redefined. On the z-axis, the z-direction coordinate interval of the lower conductor is [0, l], and the z-direction coordinate interval of the upper conductor is [l, 2l]. In view of the special connection structure of the double-layer conductor module, the currents at ends a and d are equal, and the currents at ends b and c are equal. The current J in the interval [0, 2l] is a periodic function with l as the center point, and the Fourier series expansion

[0095]

[0096] And there is

[0097]

[0098] According to the above analysis, the current in the conductor of the double-layer conductor module is a traveling wave along the axis z direction, and the charge oscillates in the z direction. At the same spatial position z, when the phase difference between the upper and lower conductor currents is 180 degrees, the electric field between the conductors is basically perpendicular to the conductor surface. In this case, the charge on the upper and lower conductors of the double-layer conductor module is in an oscillation form of "gathering-dissipation". The electromagnetic energy entering the conductor is greatly reduced, so the conductor loss is reduced.

[0099] Embodiment 2

[0100] The only difference between this embodiment and the first embodiment is that an auxiliary excitation winding is further provided in the stator assembly. Accordingly, a magnetic field modulation control module is also provided on the motor using the stator assembly. The specific description is as follows:

[0101] A stator assembly comprises the above-mentioned multi-phase winding and auxiliary excitation winding, wherein each phase winding corresponds to an auxiliary excitation winding, and the auxiliary excitation winding (or conductor) is arranged in each stator slot where a unit winding of the phase winding is located and arranged in a single layer, and the connection method of the auxiliary excitation winding is the same as that of the wavy half winding of the unit winding.

[0102] In the stator assembly, an alternating pulse current with reference to the zero-crossing moment of the alternating main magnetic field is injected into the auxiliary excitation winding through an external excitation controller, that is, an alternating pulse current is injected into the auxiliary excitation winding near the moment when the main magnetic field alternates each time, so that the auxiliary excitation winding generates an alternating pulse magnetic field, thereby generating an induced alternating potential pulse on the double-layer conductor module in the same slot. By controlling the auxiliary excitation winding current pulse waveform, a high-frequency pulse potential is generated on the double-layer conductor module.

[0103] The stator assembly including the auxiliary excitation winding and the permanent magnet rotor can also form a motor system, and the motor system can also include: a magnetic field modulation control module.

[0104] like Figure 8 As shown, a motor system includes: a motor 89 and a magnetic field modulation control module 81 connected to the motor 89, the motor 89 includes a motor stator assembly 86 and a motor rotor 88 (permanent magnet rotor), the motor stator assembly 86 includes a stator core, a motor stator multi-phase winding 85 and a motor stator auxiliary excitation winding 87; the magnetic field modulation control module 81 includes an auxiliary excitation controller 82, an excitation power supply 83 and a rotor position sensor 84. Among them, the excitation controller 82 applies an excitation pulse current to the auxiliary excitation winding 87 according to the information provided by the permanent magnet rotor position sensor 84, so that the auxiliary excitation winding 87 generates an alternating pulse magnetic field, and the alternating magnetic pulse induces a high-frequency alternating pulse potential on the double-layer conductor module. The excitation power supply 83 provides a DC power supply controlled by the excitation current for the excitation controller 82. The permanent magnet rotor position sensor 84 is used to detect the position information of each permanent magnet (having two polarities, N pole and S pole) installed on the rotor 88 during its rotation, and provide it to the excitation controller 82. The permanent magnet rotor position sensor 84 may be a magnetic encoder or a rotary transformer.

[0105] In the above motor, the pulse magnetic field generated by the pulse current passing through the auxiliary excitation winding acts on the double-layer conductor module to generate an electric potential containing high-frequency pulse components, such as Fig. 9 shown. Fig. 9 In the figure, the solid line represents the potential induced on the conductor by the pulse magnetic field generated by the auxiliary excitation winding current pulse, and the dotted line represents the potential induced on the conductor by the permanent magnet magnetic field in the motor, which is consistent with the embodiment 1. Figure 4d It is the same, and also contains high-frequency pulse components. It can be seen that the application of the auxiliary excitation winding current pulse intensifies the high-frequency pulse component. In addition, the required frequency and corresponding amplitude can be obtained by controlling the auxiliary excitation winding current pulse waveform.

[0106] When a pulse potential repeated at the alternating frequency of the main magnetic field is applied to one side of the double-layer conductor module (the energy transmission entrance side), the electric field on the energy transmission entrance side of the double-layer conductor module is impacted because the peak value of the pulse potential is higher than the potential induced by the main magnetic field, and a large amount of charges gather. With the impact of the high-frequency potential and under the action of the conductor potential, the accumulated charges diffuse and transfer to the other side of the double-layer conductor module (the energy transmission exit side).

[0107] When the stator assembly and the permanent magnet rotor move relative to each other (motor or generator state), the main magnetic field corresponding to the permanent magnet rotor generates an alternating main electric field between the upper and lower conductors of the double-layer conductor module, and the pulse magnetic field corresponding to the excitation of the auxiliary excitation winding generates a pulse potential between the upper and lower conductors of the double-layer conductor module. Under the joint action of the two electric fields, the upper and lower conductors of the double-layer conductor module excite an oscillation pattern of "gathering-dissipation" of charges. The charges are unevenly distributed in the axial direction of the conductor, and the current and induced potential on the upper and lower conductors are traveling waves.

[0108] In this embodiment, the electric potential containing high-frequency pulse components is generated on the double-layer conductor module by exciting the auxiliary winding with pulse current. The principle is the same as that of obtaining the electric potential containing high-frequency pulse components by reasonably designing the rotor magnetic steel spacing and the stator slot width in the first embodiment. Both can excite the upper and lower conductors of the double-layer conductor module to produce an oscillation form of charge "aggregation-dissipation". The current and induced potential on the upper and lower conductors are traveling waves, and the loss is reduced. Moreover, by exciting the auxiliary winding with pulse current to generate the electric potential containing high-frequency pulse components on the double-layer conductor module, the required frequency and corresponding amplitude can be obtained by controlling the auxiliary excitation winding current pulse waveform. Therefore, using the auxiliary excitation winding alone to generate an electric potential containing high-frequency pulse components on the double-layer conductor module (without setting the rotor magnetic steel spacing to be equivalent to the stator slot width), or combining the auxiliary excitation winding with the motor physical structure (setting the rotor magnetic steel spacing to be equivalent to the stator slot width) to generate an electric potential containing high-frequency pulse components on the double-layer conductor module, both produce better effects than generating an electric potential containing high-frequency pulse components on the double-layer conductor module by setting the motor physical structure alone in Example 1.

[0109] In summary, the above-mentioned motor stator winding and its components make full use of the coupling relationship between the electric, magnetic and mechanical energy inside the motor, improve the electromagnetic energy of the stator and winding components, improve the motor energy conversion rate and reduce losses.

[0110] Those skilled in the art will appreciate that the above-mentioned conductor wrapped with insulating material may be electromagnetic wire (e.g., enameled wire) commonly used in general motors, which is composed of materials with high conductivity such as copper, aluminum, or alloy and an outer insulating film, and the outer insulating material should meet the corresponding insulation withstand voltage and corona resistance properties.

[0111] The above-mentioned motor stator winding, the winding of the present invention can be conveniently matched with a multi-pole motor, and is particularly suitable for use as a stator component of a multi-pole multi-phase motor. The winding end size of the present invention is small, which saves materials, reduces copper loss, and reduces motor leakage reactance; the two sides of the winding conductor are directly in contact with the stator slot, with a large heat dissipation area and good heat dissipation effect; the winding has a large capacitance effect, which is conducive to compensating the motor winding inductance and improving the motor power factor. It can also make full use of the winding harmonic electric field energy, which has great potential for further improving the motor energy conversion rate. Therefore, the winding of the present invention has the characteristics of small leakage reactance, small conductive loss, high power factor, and the advantage of electric field participating in energy conversion, which is of great significance to improving the power (torque) density and efficiency of the motor.

[0112] It can be seen that the purpose of the present invention has been completely and effectively achieved. The functional and structural principles of the present invention have been demonstrated and explained in the embodiments. Without departing from the principles, the implementation methods can be modified arbitrarily. The present invention includes all modified implementation methods based on the spirit and scope of the claims.

Claims

1. A multi-phase winding provided on a motor stator, each phase of which is formed by connecting one or more unit windings, characterized in that: Each of the unit windings comprises: a head-end module, a plurality of intermediate modules and a terminal module and an end conductor connecting the modules, wherein the intermediate module is located between the head-end module and the terminal module; The head-end module and the middle module are both double-layer conductor modules, which are composed of an upper conductor and a lower conductor arranged in the same stator slot; the terminal module is a single-layer conductor module, which is composed of a terminal single-layer conductor arranged in a terminal stator slot; The upper conductors in all double-layer conductor modules are connected through the end conductors to form an upper wavy half winding, and the lower conductors in all double-layer conductor modules are connected through the end conductors to form a lower wavy half winding, and the upper wavy half winding and the lower wavy half winding are connected in series through the terminal single-layer conductor; all the conductors are covered with insulation; Among them, starting from the head end module, the upper conductors in all the double-layer conductor modules are connected in sequence through the end conductors, and are connected to the end module by an incoming line. At the same time, the outgoing line of the end module is connected to the lower conductor in the adjacent double-layer conductor module, and is connected in turn to the lower conductors in all the double-layer conductor modules through the end conductors, and is finally connected to the lower conductor of the head end module; or, starting from the head end module, the lower conductors in all the double-layer conductor modules are connected in sequence through the end conductors, and are connected to the end module by an incoming line. At the same time, the outgoing line of the end module is connected to the upper conductor in the adjacent double-layer conductor module, and is connected in turn to the upper conductors in all the double-layer conductor modules through the end conductors, and is finally connected to the upper conductor of the head end module.

2. The multi-phase winding according to claim 1, characterized in that: In the same stator slot, the upper and lower conductors in the same double-layer conductor module are stacked up and down along the slot depth direction, and the projections of the upper and lower conductors on the slot bottom surface at least partially overlap.

3. The multi-phase winding according to claim 1 or 2, characterized in that: Each phase winding is formed by connecting a plurality of unit windings, and the plurality of unit windings are arranged in the same double-layer space to form a double-layer composite winding.

4. The multi-phase winding according to claim 3, characterized in that: Among the multiple unit windings constituting the double-layer composite winding, there is at least one unit winding with non-equidistant spacing.

5. The multi-phase winding according to claim 3, characterized in that: The multiple unit windings constituting the double-layer composite winding include an equidistant unit winding and an even number of non-equidistant unit windings.

6. A stator assembly comprising the multi-phase winding according to any one of claims 1 to 5.

7. The stator assembly of claim 6, further comprising: Auxiliary field winding.

8. A motor, comprising the stator assembly and permanent magnet rotor as claimed in claim 6, wherein in a single unit winding, two adjacent conductor modules correspond to two adjacent magnets of the rotor respectively, and the magnets on the rotor are arranged in sequence in alternating north and south poles.

9. The motor as claimed in claim 8, wherein permanent magnets with the same width are sequentially mounted on the permanent magnet rotor, and the gaps between two adjacent magnets are equal, and the gaps are equivalent to the width of the stator slots.

10. An electric motor, comprising the stator assembly according to claim 7, a permanent magnet rotor and a magnetic field modulation control module, wherein the magnetic field modulation control module is used to control the application of an excitation pulse current to the auxiliary excitation winding.

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