Multi-channel capacitive coupler and multi-channel isop-cpt excitation system

Abstract

The application discloses a multi-channel capacitive coupler and a multi-channel ISOP-CPT excitation system, the multi-channel capacitive coupler comprises multiple channels, each channel comprises a pair of emitter plates and a pair of receiver plates, each emitter plate and each receiver plate comprises two sub-plates, the two sub-plates belonging to the same plate are electrically connected through a wire, and the two sub-plates belonging to the same plate are located on the two sides of a baseline perpendicular to a rotation shaft. By setting the arrangement position and distance of the sub-plates, the application can eliminate the coupling influence between the channels and ensure the excitation performance of the excitation system.

Description

Technical Field

[0001] This invention belongs to the field of wireless power transmission, and more specifically, relates to a multi-channel capacitive coupler and a multi-channel ISOP-CPT excitation system. Background Technology

[0002] In the field of electrically excited motors, especially in applications of electrically excited synchronous motors (EESMs), the performance of the excitation system has a decisive impact on the overall operating efficiency and reliability of the motor. Traditional EESMs employ a brushed excitation scheme with carbon brushes and slip rings. During motor operation, mechanical friction exists between the carbon brushes and slip rings, leading to numerous problems. For example, mechanical wear increases excitation losses, raises maintenance requirements, and increases the failure rate, significantly impacting the motor's reliability and lifespan. In applications with extremely stringent stability requirements, such as new energy vehicles and marine electric propulsion, the limitations of this brushed excitation method are particularly pronounced.

[0003] With the continuous development of Capacitive Power Transfer (CPT) technology, CPT wireless excitation technology, which applies CPT technology to motor excitation systems, has gradually become a key path to solve the aforementioned problems. In a CPT wireless excitation system, the transmitting-side plate remains stationary while the receiving-side plate rotates together with the motor shaft. Without axial displacement, the electric field between the plates remains constant, thus enabling efficient energy transfer from the transmitting end to the receiving end using the electric field generated by the plates. This frees the power supply end and rotor windings from the constraints of physical wires. However, existing single-channel CPT wireless excitation systems are limited by the constraints of power electronic devices. The voltage withstand rating of individual inverters in the system is limited, making it impossible to directly draw power from the medium-voltage DC grid to provide excitation current for the EESM (Electrical Excitation System). This significantly restricts the widespread application of CPT wireless excitation technology in EESM excitation systems, thus necessitating the development of new technologies and structures to address these challenges. In the field of Wireless Power Transfer (WPT), a multi-channel technology based on input series and output parallel (ISOP) increases the number of transmission channels and changes the connection method of the channels to achieve parallel transmission of electrical energy, demonstrating a performance improvement that traditional single-channel systems cannot match, and can effectively solve the above problems.

[0004] In an ISOP multi-channel system, the inverters for each channel are connected in series on the DC side. Compared to the traditional single-channel system, which requires a DC-DC step-down to reduce the inverter's voltage to its withstand range, the ISOP multi-channel system allows each inverter to withstand a voltage drop of 1 / N of the bus voltage (where N is the number of channels). The rectifiers for each channel are connected in parallel on the DC side, distributing the single-channel current across multiple channels while maintaining a constant total power. The current in a single channel is only 1 / N of that in a traditional single-channel system, significantly reducing conductor losses and device overheating. Therefore, there is an urgent need to apply ISOP multi-channel technology to the CPT wireless excitation field and develop a multi-channel ISOP-CPT wireless excitation system suitable for EESM.

[0005] Meanwhile, in the actual operation of a multi-channel CPT system, the plates of different channels of the coupler will couple with each other to generate coupling capacitance, causing the voltage, current, phase and other parameters of each channel to be related to each other, forming a strongly coupled nonlinear system. This makes the stable operation conditions of the multi-channel system more complex than those of the single-channel system, and the resonance condition and output characteristics of the system will also be affected. Therefore, achieving decoupling between coupler channels is a problem that must be solved for multi-channel CPT systems. Summary of the Invention

[0006] In view of the above-mentioned defects or improvement needs of the prior art, the present invention provides a multi-channel capacitive coupler and a multi-channel ISOP-CPT excitation system, which can eliminate the coupling effect between channels and ensure the excitation performance of the excitation system.

[0007] To achieve the above objectives, according to one aspect of the present invention, a multi-channel capacitive coupler is provided, comprising: Multiple channels are arranged along the axial direction of the rotor shaft of the synchronous motor. The middle channel is designated as the first channel, and the channels from the middle to both sides are designated as the first channel, the second channel, ..., the Nth channel, where N is the total number of channels. Each channel includes a pair of transmitting plates and a pair of receiving plates. Each transmitting plate is fixedly connected to the stator of the synchronous motor, and each receiving plate is fixedly connected to the rotating shaft. The rotation of the rotating shaft drives the receiving plates to rotate. Each emitting electrode and each receiving electrode includes two sub-electrodes. The two sub-electrodes belonging to the same electrode are electrically connected by a wire. The two sub-electrodes belonging to the same electrode are located on both sides of a baseline perpendicular to the rotating shaft. In odd-numbered channels, the two sub-electrodes belonging to the same electrode are symmetrically distributed along the baseline axis. In even-numbered channels, the sub-electrodes belonging to the emitting electrode and the sub-electrodes belonging to another emitting electrode in the same channel are symmetrically distributed along the baseline axis. The sub-electrodes belonging to the receiving electrode and the sub-electrodes belonging to another receiving electrode in the same channel are symmetrically distributed along the baseline axis. Four sub-electrodes located on the same side of the baseline in the same channel form a sub-coupling mechanism. In each sub-coupling mechanism, the sub-electrodes belonging to the emitting electrode and the sub-electrodes belonging to the receiving electrode are coupled face-to-face. The spacing between any two adjacent sub-electrodes in each sub-coupling mechanism is equal. The spacing between adjacent sets of sub-coupled mechanisms is equal.

[0008] Preferably, in each set of sub-coupling mechanisms, the two sub-plates belonging to the receiving plate are located inside the two sub-plates belonging to the transmitting plate.

[0009] Preferably, in each set of sub-coupling mechanisms, the two sub-plates belonging to the receiving plate are located outside the two sub-plates belonging to the transmitting plate.

[0010] Preferably, the wires connecting the two sub-plates of the receiving plate are located inside the rotating shaft.

[0011] Preferably, the wires connecting the two sub-plates of the emitting electrode are located outside the rotating shaft.

[0012] Preferably, both the transmitting electrode and the receiving electrode have holes in the middle. The transmitting electrode is sleeved on the rotating shaft through the hole without contacting the rotating shaft, and the receiving electrode is sleeved on the rotating shaft through the hole and is insulated from and fixedly connected to the rotating shaft.

[0013] Preferably, both the emitting electrode and the receiving electrode are disc-shaped, with their centers facing each other and having the same shape and size.

[0014] Preferably, all sub-electrodes are parallel to the baseline.

[0015] According to another aspect of the present invention, a multi-channel ISOP-CPT excitation system is provided, including a multi-channel capacitive coupler, the multi-channel capacitive coupler comprising: Multiple channels are arranged along the axial direction of the rotor shaft of the synchronous motor. The middle channel is designated as the first channel, and the channels from the middle to both sides are designated as the first channel, the second channel, ..., the Nth channel, where N is the total number of channels. Each channel includes a pair of transmitting plates and a pair of receiving plates. Each transmitting plate is fixedly connected to the stator of the synchronous motor, and each receiving plate is fixedly connected to the rotating shaft. The rotation of the rotating shaft drives the receiving plates to rotate. Each emitting electrode and each receiving electrode includes two sub-electrodes. The two sub-electrodes belonging to the same electrode are electrically connected by a wire. The two sub-electrodes belonging to the same electrode are located on both sides of a baseline perpendicular to the rotating shaft. In odd-numbered channels, the two sub-electrodes belonging to the same electrode are symmetrically distributed along the baseline axis. In even-numbered channels, the sub-electrodes belonging to the emitting electrode and the sub-electrodes belonging to another emitting electrode in the same channel are symmetrically distributed along the baseline axis. The sub-electrodes belonging to the receiving electrode and the sub-electrodes belonging to another receiving electrode in the same channel are symmetrically distributed along the baseline axis. Four sub-electrodes located on the same side of the baseline in the same channel form a sub-coupling mechanism. In each sub-coupling mechanism, the sub-electrodes belonging to the emitting electrode and the sub-electrodes belonging to the receiving electrode are coupled face-to-face. The spacing between any two adjacent sub-electrodes in each sub-coupling mechanism is equal. The spacing between adjacent sets of sub-coupled mechanisms is equal.

[0016] Preferably, each channel further includes a transmitter-side circuit and a receiver-side circuit. The transmitter-side circuit is electrically connected to the transmitter plate of the channel and includes an inverter and a transmitter-side compensation network. The receiver-side circuit is electrically connected to the receiver plate of the channel and includes a rectifier and a receiver-side compensation network.

[0017] Overall, the technical solutions conceived in this invention have beneficial effects compared with the prior art: (1) The present invention proposes a multi-channel capacitive coupler that can eliminate the coupling effect between channels in a multi-channel CPT system and ensure the stability of the system's resonance and output characteristics.

[0018] (2) This invention proposes a multi-channel ISOP-CPT excitation system, which is suitable for synchronous motors. This system can make up for the defect of the traditional single-channel CPT wireless excitation system that requires DC-DC step-down to the inverter's withstand voltage range. Under the same input voltage, the voltage drop of each inverter in the multi-channel system is 1 / N of that in the single-channel system, where N is the number of channels. Under the premise of maintaining the total power unchanged, the excitation current of the single channel is distributed to multiple channels, and the excitation current of a single channel is only 1 / N of that in the traditional single-channel system, which significantly reduces the problems of conductor loss and excitation loss. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall multi-channel ISOP-CPT excitation system according to an embodiment of the present invention; Figure 2 This is a circuit diagram of the multi-channel ISOP-CPT excitation system according to an embodiment of the present invention; Figure 3 This is the AC equivalent circuit diagram of the multi-channel ISOP-CPT excitation system according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the electrode arrangement of a multi-channel capacitive coupler containing two channels according to an embodiment of the present invention; Figure 5 This is a transformation diagram of the three equivalent models of CPT couplers in embodiments of the present invention; Figure 6 This is an exploded view of the assembly of a multi-channel capacitive coupler containing two channels according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the wire connection of a multi-channel capacitive coupler according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the electrode arrangement of a multi-channel capacitive coupler containing three channels according to an embodiment of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0021] In the description of the embodiments of this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly specified. The terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.

[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0023] This invention provides a multi-channel capacitive coupler and a multi-channel ISOP-CPT excitation system. The ISOP-CPT excitation system refers to a capacitive power transfer excitation system with input series connection and output parallel connection, which will be described separately below.

[0024] Figure 1 This invention provides a multi-channel ISOP-CPT excitation system suitable for synchronous motors. It includes N channels, each comprising a transmitting side and a receiving side. The transmitting side is fixedly connected to the motor housing and remains stationary throughout motor operation. The transmitting side includes a transmitting side circuit and a transmitting electrode plate 4. The transmitting side circuit includes an inverter 2 and a transmitting side compensation network 3. The receiving side is fixed to the rotating shaft and rotates coaxially with the motor rotor. The receiving side includes a receiving side circuit and a receiving electrode plate 5. The receiving side circuit includes a receiving side compensation network 6 and a rectifier 7. The inverters 1 of each channel are connected in series on the DC side, and the rectifiers 5 of each channel are connected in parallel on the DC side.

[0025] The transmitting side obtains constant DC power from DC power supply facilities 1 such as medium-voltage DC grid. After multi-channel series voltage division, the voltage of each channel inverter 2 is reduced to 1 / N of the bus voltage. Then, the inverter 2 converts the divided DC power into a high-frequency AC square wave and injects it into the transmitting side compensation network 3. After the harmonic components are filtered out by the transmitting side compensation network, it becomes a high-frequency sinusoidal voltage / current and is connected to the transmitting plate 4.

[0026] There is electric field coupling between the transmitting plate 4 and the receiving plate 5, which can be regarded as a capacitor, allowing high-frequency sinusoidal voltage / current to flow normally, thus completing the energy transfer from the transmitting side to the receiving side. The high-frequency sinusoidal voltage / current flowing into the receiving side is conditioned by the receiving side compensation network 6 and then enters the rectifier 7, where it is converted into DC current. After being connected in parallel, the total output current is supplied to the excitation winding 8 on the rotor of the electrically excited motor.

[0027] Figure 2 This is a specific circuit diagram of a multi-channel ISOP-CPT excitation system according to an embodiment of the present invention. The DC power supply facility 1 is a DC power source, which, after being divided in series by multiple channels, supplies DC power to each channel. The system has two channels with identical configurations, both employing an LCLC-CLC compensation network. In the first channel, the inverter 2 uses a full-bridge topology, and a voltage-regulating capacitor is connected in parallel at its input port. C i1 The transmitter-side compensation network 3 includes series inductors. L f1 Parallel capacitors C f1 Series inductor L 1 and parallel capacitor C e1Two transmitting plates 4 are connected to the two outgoing lines of the transmitting-side compensation network 3, respectively; two receiving plates 5 are connected to the two outgoing lines of the receiving-side compensation network 6; the receiving-side compensation network 6 includes parallel capacitors. C e3 Parallel inductors L 3 and parallel capacitors C f3 Rectifier 7 adopts a full-bridge topology, with a filter capacitor connected in parallel at the rear end. C o3 In the second channel, inverter 2 adopts a full-bridge topology, and a voltage-regulating capacitor is connected in parallel at the input port. C i2 The transmitter-side compensation network 3 includes series inductors. L f2 Parallel capacitors C f2 Series inductor L 2 and parallel capacitors C e2 Two transmitting plates 4 are connected to the two outgoing lines of the transmitting-side compensation network 3, respectively; two receiving plates 5 are connected to the two outgoing lines of the receiving-side compensation network 6; the receiving-side compensation network 6 includes parallel capacitors. C e4 Parallel inductors L 4 and parallel capacitors C f4 Rectifier 7 adopts a full-bridge topology, with a filter capacitor connected in parallel at the rear end. C o4 The outputs of the two channels are connected in parallel and then connected to the excitation winding 8; the excitation winding 8 is composed of a resistor. R o express.

[0028] Based on the fundamental frequency analysis method and the equivalent modeling method for multi-channel CPT couplers, the AC equivalent circuit of this embodiment is obtained, wherein the compensation capacitor connected in parallel with the coupler is... C e1 , C e2 , C e3 , C e4 This is considered part of the coupler port self-capacitance and will not be considered separately in subsequent analyses. For example... Figure 3 As shown, where U 1 and U 2 represents the AC voltage obtained after the DC power from each input channel is converted by inverter 1. I f1 , I f2 This refers to the AC current output by inverter 1 in each channel. I f3 ,I f4 To input the AC current to each channel rectifier 7, R 3 and R 4 represents the equivalent DC resistance of each channel's output side. I 1. I 2. I 3. I 4 represents the current at each port of the coupler. C 1. C 2. C 3. C 4 represents the self-capacitance of each port of the coupler. U 12 , U 13 , U 14 , U 21 , U 23 , U 24 , U 31 , U 32 , U 34 , U 41 , U 42 , U 43 The controlled voltage sources at each port of the coupler are represented by the mutual capacitance between the coupler ports, and the controlled voltage sources at ports a and b are expressed as follows: , ; in I b For the current at coupler port b, C VMab Let be the mutual capacitance between coupler ports a and b, where 'a' represents the port number where the controlled voltage source is located, 'b' represents the port numbers of the remaining ports, and 'j' represents a complex number. ω This refers to the system's operating angular frequency. During system operation, the operating frequency is typically kept consistent with the system's resonant frequency. The system's parameter configuration method is as follows: ; ; in f This is the system resonant frequency. Under this resonant condition, the LCLC-CLC single-channel CPT system can achieve both constant current output and zero voltage switching (ZVS) characteristics.

[0029] Based on the above resonance condition, the inverter output current of each channel in the LCLC-CLC dual-channel CPT system is derived using the loop current method. I f1 , I f2 and rectifier input current I f3 , I f4 The expression is ; ; A, B, C, D, E, and F are intermediate auxiliary variables: ; In the formula Z Vab The mutual impedance between port a and port b can be expressed as: ; It can be seen that, due to the mutual coupling between different channel ports, the existing dual-channel ISOP-CPT wireless excitation system cannot be decoupled from the load to achieve constant current output; the inverter output current cannot keep in phase with the inverter output voltage, and the system cannot achieve ZPA characteristics.

[0030] Therefore, the multi-channel ISOP-CPT excitation system of this invention includes a multi-channel capacitive coupler. The multi-channel capacitive coupler includes multiple channels arranged along the axial direction of the rotating shaft, with the middle channel designated as the first channel, and the channels from the middle outwards sequentially designated as the first channel, second channel, ..., Nth channel, where N is the total number of channels. Each channel includes a pair of emitting plates and a pair of receiving plates. Each emitting plate is fixedly connected to the stator of the synchronous motor, and each receiving plate is fixedly connected to the rotating shaft of the synchronous motor rotor. The rotation of the rotating shaft drives the receiving plates to rotate. Each emitting plate and each receiving plate includes two sub-plates. The two sub-plates belonging to the same plate are electrically connected by wires. The plates are located on both sides of a baseline perpendicular to the rotating shaft. In odd-numbered channels, two sub-plates belonging to the same plate are symmetrically distributed along the baseline axis. In even-numbered channels, the sub-plate belonging to the emitting plate and the sub-plate belonging to another emitting plate in the same channel are symmetrically distributed along the baseline axis. The sub-plate belonging to the receiving plate and the sub-plate belonging to another receiving plate in the same channel are symmetrically distributed along the baseline axis. Four sub-plates located on the same side of the baseline in the same channel form a sub-coupling mechanism. In each sub-coupling mechanism, the sub-plate belonging to the emitting plate and the sub-plate belonging to the receiving plate are coupled face-to-face. The spacing between any two adjacent sub-plates in each sub-coupling mechanism is equal. The spacing between any two adjacent sub-coupling mechanisms is also equal.

[0031] Figure 4 This is a layout diagram of a multi-channel capacitive coupler with two channels according to an embodiment of the present invention, where N=2. As shown in the figure, the coupler includes two channels, each channel including two transmitting plates 4 and two receiving plates 5. The transmitting plates 4 of the first channel include a first transmitting plate 41 and a second transmitting plate 42, and the receiving plates 5 include a first receiving plate 51 and a second receiving plate 52. The transmitting plates 4 of the second channel include a third transmitting plate 43 and a fourth transmitting plate 44, and the receiving plates 5 include a third receiving plate 53 and a fourth receiving plate 54. Each plate actually contains two sub-plates. After being electrically connected by wires, the two sub-plates belonging to the same plate have the same potential. Therefore, in circuit equivalence, two sub-plates can be combined and regarded as one plate. A single channel has a total of eight sub-plates, which are divided into two groups of sub-coupling mechanisms according to the different plates they belong to, so that the four sub-plates contained in each group of sub-coupling mechanisms must belong to different plates. In one embodiment, in the sub-coupling mechanism, the two sub-plates belonging to the transmitting plate 4 are located on the outer side, and the two sub-plates belonging to the receiving plate 5 are located on the inner side. The four sub-plates are coupled to each other and are evenly distributed at equal distances, each d1.

[0032] It should be noted that, in each set of sub-coupling mechanisms, the two sub-plates belonging to the receiving plate can be located outside the two sub-plates belonging to the transmitting plate.

[0033] The two sets of sub-coupling mechanisms in the first channel are symmetrically arranged along the motor shaft 9. The two sets of sub-coupling mechanisms in the second channel are arranged in the same direction along the motor shaft 9. Taking the axis of symmetry of the two sets of sub-coupling mechanisms in the first channel as the baseline, the two sets of sub-coupling mechanisms in the same channel are located on both sides of the baseline. All sub-coupling mechanisms are arranged sequentially from the baseline to both ends of the motor shaft 9 in ascending order of channel number along the motor axis. The spacing between the sub-coupling mechanisms is equal, all being d2. In the first channel, the two sub-electrodes belonging to the same electrode plate are symmetrically distributed along the baseline axis. In the second channel, the sub-electrodes belonging to the third emitting electrode plate 43 and the sub-electrodes belonging to the fourth emitting electrode plate 44 in the same channel are symmetrically distributed along the baseline axis. The sub-electrodes belonging to the third receiving electrode plate 53 and the sub-electrodes belonging to the fourth receiving electrode plate 54 in the same channel are symmetrically distributed along the baseline axis.

[0034] The spacing d2 between two adjacent sets of sub-coupling mechanisms is preferably 20 mm, and the spacing d1 between the four sub-plates of a set of sub-coupling mechanisms is preferably 10 mm.

[0035] Preferably, all sub-electrodes are parallel to the baseline.

[0036] Taking the four plates at ports a (a=1) and b (b=2) as an example, as follows: Figure 5As shown, according to the mechanism of capacitance generation, an equivalent capacitance is generated between every two plates. The capacitance between the first emitter plate 41 and the second emitter plate 42 is C. 41,42 The capacitance between the first emitter plate 41 and the third emitter plate 43 is C. 41,43 The capacitance between the first emitter plate 41 and the fourth emitter plate 44 is C. 41,44 The capacitance between the second emitter plate 42 and the third emitter plate 43 is C. 42,43 The capacitance between the second emitter plate 42 and the fourth emitter plate 44 is C. 42,44 The capacitance between the third emitter plate 43 and the fourth emitter plate 44 is C. 43,44 Therefore, a total of 6 equivalent capacitances are generated between the four plates. Based on the series and parallel relationship of these 6 capacitors, they can be further equivalent to 3 series-parallel capacitors in the circuit, namely 2 parallel capacitors C. P C S and a series capacitor C M12 The calculation principle for equivalent capacitance is as follows: ; In the formula, C P12 C represents the emitter-side self-capacitance of the coupler. S12 C represents the self-capacitance on the receiving side of the coupler. M12 This represents the mutual capacitance between the transmitting and receiving sides of the coupler.

[0037] Based on circuit principles, the three series-parallel capacitors mentioned above can be further represented as a coupler-controlled voltage source model, C VP12 C represents the equivalent resonant capacitance on the emitter side of the coupler. VS12 C represents the equivalent resonant capacitance on the receiving side of the coupler. VM12 The equivalent mutual capacitance between the transmitting and receiving sides of the coupler is represented by the following calculation principle: ; According to the structural design and positional arrangement of the coupler in the embodiment of the present invention, the relative positions and distances between the first emitting plate 41 and the third emitting plate 43 and the fourth emitting plate 44 are the same, and the relative positions and distances between the second emitting plate 42 and the third emitting plate 43 and the fourth emitting plate 44 are the same. According to the mechanism of capacitance generation, the capacitance between the four plates satisfies the following relationship. ; According to the equivalence principle, series capacitors C M12 The equivalent mutual capacitance between port a (a=1) and port b (b=2) is equal to zero. C VM12 The mutual impedance between port a (a=1) and port b (b=2) tends towards infinity.Z V12 The impedance is equal to zero, thus decoupling port a (a=1) from port b (b=2). Similarly, based on the above derivation, the mutual impedance between port a (a=1) and port b (b=4) can be derived. Z V14 The mutual impedance between port a (a=2) and port b (b=3) Z V23 The mutual impedance between port a (a=3) and port b (b=4) Z V34 If all values ​​are zero, it means that the coupler can decouple different channel ports.

[0038] Figure 6 This is a schematic diagram of the coupler assembly according to an embodiment of the present invention. Figure 6 As shown, the coupler includes two channels, each consisting of two emitting plates 4 and two receiving plates 5. The emitting plates 4 of the first channel include a first emitting plate 41 and a second emitting plate 42, and the receiving plates 5 include a first receiving plate 51 and a second receiving plate 52. The emitting plates 4 of the second channel include a third emitting plate 43 and a fourth emitting plate 44, and the receiving plates 5 include a third receiving plate 53 and a fourth receiving plate 54. Each plate can actually contain two sub-plates. After being electrically connected by wires, the two sub-plates belonging to the same plate have the same potential. Therefore, in circuit equivalence, two sub-plates can be combined and considered as one plate. Figure 7 As shown, the wires connecting the sub-electrode of the transmitting electrode 4 are located outside the rotating shaft, while the wires connecting the sub-electrode of the receiving electrode 5 are located inside the motor rotating shaft 9, enabling them to rotate synchronously with the motor rotating shaft 9. A single channel has eight sub-electrodes, which are divided into two groups of sub-coupling mechanisms according to their respective electrode plates, ensuring that each group of sub-coupling mechanisms contains four sub-electrodes belonging to different electrode plates. In the sub-coupling mechanism, the two sub-electrodes belonging to the transmitting electrode 4 are located on the outer side, and the two sub-electrodes belonging to the receiving electrode 5 are located on the inner side. The four sub-electrodes are coupled facing each other and evenly distributed at equal distances.

[0039] The two sets of sub-coupling mechanisms in the first channel are arranged symmetrically along the motor shaft 9. The two sets of sub-coupling mechanisms in the second channel are arranged in the same direction along the motor shaft 9. Taking the axis of symmetry of the two sets of sub-coupling mechanisms in the first channel as the baseline, the two sets of sub-coupling mechanisms in the same channel are located on both sides of the baseline. All sub-coupling mechanisms are arranged sequentially from the baseline to both ends of the motor shaft 9 in the motor axis according to the channel number from small to large. The spacing between the sub-coupling mechanisms is equal.

[0040] The transmitting plate 4 is fixed to the motor housing and remains stationary throughout the motor's operation; the receiving plate 5 is fixed to the motor shaft 9 and rotates coaxially with the motor rotor.

[0041] Both the transmitting electrode 4 and the receiving electrode 5 are disc-shaped with a circular through hole in the center. They are made of a single piece of metal with good conductivity (such as aluminum or copper). The transmitting electrode 4 is sleeved on the motor shaft 9 through the circular hole without contacting the motor shaft 9. The receiving electrode 5 is sleeved on the motor shaft 9 through the circular hole and is insulated from the motor shaft 9 and fixedly connected.

[0042] Figure 8 This is a schematic diagram of the sub-electrode arrangement of a three-channel multi-channel capacitive coupler according to an embodiment of the present invention. The third channel includes a fifth transmitting electrode 45, a sixth transmitting electrode 46, a fifth receiving electrode 55, and a sixth receiving electrode 56.

[0043] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-channel capacitive coupler, characterized in that, include: Multiple channels are arranged along the axial direction of the rotor shaft of the synchronous motor. The middle channel is designated as the first channel, and the channels from the middle to both sides are designated as the first channel, the second channel, ..., the Nth channel, where N is the total number of channels. Each channel includes a pair of transmitting plates and a pair of receiving plates. Each transmitting plate is fixedly connected to the stator of the synchronous motor, and each receiving plate is fixedly connected to the rotating shaft. The rotation of the rotating shaft drives the receiving plates to rotate. Each emitting electrode and each receiving electrode includes two sub-electrodes. The two sub-electrodes belonging to the same electrode are electrically connected by a wire. The two sub-electrodes belonging to the same electrode are located on both sides of a baseline perpendicular to the rotating shaft. In odd-numbered channels, the two sub-electrodes belonging to the same electrode are symmetrically distributed along the baseline axis. In even-numbered channels, the sub-electrodes belonging to the emitting electrode and the sub-electrodes belonging to another emitting electrode in the same channel are symmetrically distributed along the baseline axis. The sub-electrodes belonging to the receiving electrode and the sub-electrodes belonging to another receiving electrode in the same channel are symmetrically distributed along the baseline axis. Four sub-electrodes located on the same side of the baseline in the same channel form a sub-coupling mechanism. In each sub-coupling mechanism, the sub-electrodes belonging to the emitting electrode and the sub-electrodes belonging to the receiving electrode are coupled face-to-face. The spacing between any two adjacent sub-electrodes in each sub-coupling mechanism is equal. The spacing between adjacent sets of sub-coupled mechanisms is equal.

2. The multi-channel capacitive coupler as described in claim 1, characterized in that, In each set of sub-coupling mechanisms, the two sub-plates belonging to the receiving plate are located inside the two sub-plates belonging to the transmitting plate.

3. A multi-channel capacitive coupler as described in claim 1, characterized in that, In each sub-coupling mechanism, the two sub-plates belonging to the receiving plate are located outside the two sub-plates belonging to the transmitting plate.

4. A multi-channel capacitive coupler as described in claim 1, characterized in that, The wires connecting the two sub-plates of the receiving plate are located inside the rotating shaft.

5. A multi-channel capacitive coupler as described in claim 1, characterized in that, The wires connecting the two sub-plates of the emitting electrode are located outside the rotating shaft.

6. A multi-channel capacitive coupler as described in claim 1, characterized in that, Both the transmitting electrode and the receiving electrode have holes in the middle. The transmitting electrode is sleeved on the rotating shaft through the hole but does not contact the rotating shaft. The receiving electrode is sleeved on the rotating shaft through the hole and is insulated from and fixedly connected to the rotating shaft.

7. A multi-channel capacitive coupler as described in claim 1, characterized in that, Both the emitting and receiving electrodes are disc-shaped, with their centers facing each other and having the same shape and size.

8. A multi-channel capacitive coupler as described in claim 1, characterized in that, All sub-electrodes are parallel to the baseline.

9. A multi-channel ISOP-CPT excitation system, characterized in that, Includes a multi-channel capacitive coupler, the multi-channel capacitive coupler comprising: Multiple channels are arranged along the axial direction of the rotor shaft of the synchronous motor. The middle channel is designated as the first channel, and the channels from the middle outwards are designated as the first channel, the second channel, ..., the Nth channel, where N is the total number of channels. Each channel includes a pair of transmitting plates and a pair of receiving plates. Each transmitting plate is fixedly connected to the stator of the synchronous motor, and each receiving plate is fixedly connected to the rotating shaft. The rotation of the rotating shaft drives the receiving plates to rotate. Each emitting electrode and each receiving electrode includes two sub-electrodes. The two sub-electrodes belonging to the same electrode are electrically connected by a wire. The two sub-electrodes belonging to the same electrode are located on both sides of a baseline perpendicular to the rotating shaft. In odd-numbered channels, the two sub-electrodes belonging to the same electrode are symmetrically distributed along the baseline axis. In even-numbered channels, the sub-electrodes belonging to the emitting electrode and the sub-electrodes belonging to another emitting electrode in the same channel are symmetrically distributed along the baseline axis. The sub-electrodes belonging to the receiving electrode and the sub-electrodes belonging to another receiving electrode in the same channel are symmetrically distributed along the baseline axis. Four sub-electrodes located on the same side of the baseline in the same channel form a sub-coupling mechanism. In each sub-coupling mechanism, the sub-electrodes belonging to the emitting electrode and the sub-electrodes belonging to the receiving electrode are coupled face-to-face. The spacing between any two adjacent sub-electrodes in each sub-coupling mechanism is equal. The spacing between adjacent sets of sub-coupled mechanisms is equal.

10. A multi-channel ISOP-CPT excitation system as described in claim 9, characterized in that, Each channel also includes a transmitter-side circuit and a receiver-side circuit. The transmitter-side circuit is electrically connected to the transmitter plate of the channel and includes an inverter and a transmitter-side compensation network. The receiver-side circuit is electrically connected to the receiver plate of the channel and includes a rectifier and a receiver-side compensation network.

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