Motor device, electric drive system and vehicle

Abstract

The present application relates to the field of vehicles, and more particularly to an electric machine arrangement comprising a stator core, a rotor core, a rotor shaft, and a winding having a neutral point, the electric machine arrangement further comprising: a common mode resonance conductor connected at a first end to the neutral point, and comprising at least an axial section extending inside a yoke portion of the stator core in an axial direction of the electric machine arrangement; a resonance network connected between a second end of the common mode resonance conductor and a reference potential terminal for generating a resonance current in the axial section in response to a jump in common mode voltage in the winding; the axial section being configured to cause the resonance current flowing therethrough to generate a circumferential toroidal magnetic field in the stator core in a direction opposite to a circumferential toroidal magnetic field generated in the stator core by a common mode current in the winding.

Description

Technical Field

[0001] This application relates to the field of vehicles, and more specifically to an electric motor, an electric drive system, and a vehicle. Background Technology

[0002] The common-mode current in the motor windings is coupled to the rotor through the magnetic circuit, generating a high-frequency potential difference at both ends of the rotor shaft, forming a magnetic field-coupled shaft voltage. This shaft voltage forms a high-frequency loop current through the bearing and tooth surface, generating Joule heat when flowing through the bearing and tooth surface. Long-term accumulation can lead to damage to the bearing raceway and tooth surface, causing vibration and noise in the electric drive system.

[0003] Currently, there are two main solutions to this problem: one is to use ceramic ball insulated bearings, but the ceramic rolling elements are sensitive to impact loads, posing a risk of breakage and are also costly; the other is to use common-mode filter magnetic rings, but this requires expensive nanocrystalline materials, and the cost increases with the size of the magnetic ring. Therefore, a lower-cost and more robust solution is needed.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this application, and the information described therein does not necessarily constitute prior art known to those skilled in the art. Summary of the Invention

[0005] In view of the above problems, this application aims to provide an electric motor device, an electric drive system, and a vehicle.

[0006] According to a first aspect of this application, an electric motor device is provided, including a stator core, a rotor core, a rotor shaft, and a winding having a neutral point. The electric motor device further includes: a common-mode resonant conductor, a first end of which is connected to the neutral point, and the common-mode resonant conductor includes at least an axial segment extending along the axial direction of the electric motor device inside the yoke of the stator core; a resonant network connected between a second end of the common-mode resonant conductor and a reference potential end, for generating a resonant current in the axial segment in response to a jump in the common-mode voltage in the winding; the axial segment is configured such that the direction of the circumferential annular magnetic field generated in the stator core by the resonant current flowing therethrough is opposite to the direction of the circumferential annular magnetic field generated in the stator core by the common-mode current in the winding.

[0007] As an alternative or supplement to the above solutions, in a motor device according to an embodiment of this application, the axial section is disposed in the stator slot of the stator core, or disposed in an axial channel opened on the stator core.

[0008] As an alternative or supplement to the above solution, in a motor device according to an embodiment of this application, after the common-mode resonant conductor is led out from the neutral point, it is routed through the outside of the stator core to one end of the motor device in the axial direction, enters the stator core from the one end, and is routed along the axial direction to the other end of the motor device in the axial direction.

[0009] As an alternative or supplement to the above solutions, in a motor device according to an embodiment of this application, the common-mode resonant conductor is a single-turn conductor or a multi-turn parallel conductor composed of multiple turns of conductors connected in parallel.

[0010] As an alternative or supplement to the above solutions, in a motor device according to an embodiment of this application, the resonant network includes one or more of the following elements: a resistive element, an inductive element, and a capacitive element.

[0011] As an alternative or supplement to the above solutions, in a motor device according to an embodiment of this application, the element parameters of the resonant network are configured such that the resonant frequency of the resonant current is the same as the oscillation frequency of the common-mode current, and the decay time constant of the resonant current is equal to the decay time constant of the common-mode current.

[0012] According to a second aspect of this application, a motor device is provided, including a stator core, a rotor core, a rotor shaft, and a winding having a neutral point. The motor device further includes a common-mode resonant conductor; a first end of the common-mode resonant conductor is connected to the neutral point, a second end is connected to a reference potential terminal, and the common-mode resonant conductor includes at least an axial segment extending along the axial direction of the motor device inside the yoke of the stator core; the common-mode resonant conductor is configured to generate a resonant current in the axial segment in response to a jump in the common-mode voltage in the winding, based on a preset parasitic parameter of the reference potential terminal; the axial segment is configured such that the direction of the circumferential annular magnetic field generated in the stator core by the resonant current flowing therethrough is opposite to the direction of the circumferential annular magnetic field generated in the stator core by the common-mode current in the winding.

[0013] As an alternative or supplement to the above solutions, in a motor device according to an embodiment of this application, the preset parasitic parameters correspond to the physical parameters of the common-mode resonant conductor, wherein the physical parameters include one or more of the following: material, cross-sectional dimensions, number of parallel turns, and insulation layer thickness.

[0014] As an alternative or supplement to the above solutions, in a motor device according to an embodiment of this application, the preset parasitic parameters include one or more of the following: parasitic capacitance, parasitic inductance, and parasitic resistance.

[0015] According to a third aspect of this application, an electric drive system is provided, which includes the motor device described in the first or second aspect of this application.

[0016] According to a fourth aspect of this application, a vehicle is provided that includes the electric drive system described in a third aspect of this application. Attached Figure Description

[0017] The above and / or other aspects and advantages of this application will become clearer and more readily understood from the following description taken in conjunction with the accompanying drawings, in which the same or similar elements are denoted by the same reference numerals. The drawings include: Figure 1 A schematic diagram is shown of the magnetic field generated by the common-mode current and its induced shaft voltage; Figure 2 A structural block diagram of a motor device for suppressing high-frequency loop current according to some embodiments of this application is shown; Figure 3 An exemplary circuit diagram of a resonant network according to some embodiments of this application is shown; Figure 4 A schematic diagram illustrating the principle of how a resonant current generates a reverse circumferential ring magnetic field in the stator core and cancels out the shaft voltage according to some embodiments of this application is shown. Detailed Implementation

[0018] The following are some embodiments of this application, intended to provide a basic understanding of the application. They are not intended to identify key or decisive elements of the application or to limit the scope of protection sought.

[0019] For purposes of brevity and illustrativeness, the principles of this application are described herein primarily with reference to exemplary embodiments thereof. However, those skilled in the art will readily recognize that the same principles are equivalently applicable to all types of motor devices, electric drive systems, and vehicles, and that these same principles can be implemented therein, and that any such variations do not depart from the true spirit and scope of this patent application.

[0020] Furthermore, reference is made in the accompanying drawings, which illustrate specific exemplary embodiments. Electrical, mechanical, logical, and structural modifications may be made to these embodiments without departing from the spirit and scope of this application. Moreover, while features of this application are disclosed in conjunction with only one of several embodiments, such features may be combined with one or more other features of other embodiments if desired and / or advantageous for any given or identifiable function. Therefore, the following description should not be construed as limiting, and the scope of this application is defined by the appended claims and their equivalents.

[0021] Terms such as "possessing" and "comprising" indicate that, in addition to the units (modules) and steps directly and explicitly stated in the specification and claims, the technical solution of this application does not exclude the presence of other units (modules) and steps not directly or explicitly stated. Terms such as "first" and "second" do not indicate the order of the units in terms of time, space, size, etc., but are merely used to distinguish the units. Furthermore, the steps in this document are not limited to being performed in the order they are written; a step written later may be performed simultaneously with or before a step written earlier.

[0022] In this application, the term "high-frequency loop current" refers to the high-frequency interference current generated in the motor components of an electric drive system due to the high-frequency switching action of power devices. This high-frequency loop current can form a closed loop through contact points such as bearing raceways and gear tooth surfaces, and can generate Joule heating at the contact points, causing electro-corrosion and vibration noise. The typical frequency range of high-frequency loop current can be from hundreds of kHz to several MHz, but this application is not limited to this.

[0023] In this application, the term "common-mode current" refers to high-frequency interference current components with the same direction and waveform on the three-phase windings of an electric drive system. This common-mode current can be excited by the high-frequency common-mode voltage (i.e., the zero-sequence component of the three-phase voltage) output by the frequency converter and can form a common-mode circuit through the parasitic capacitance inside the motor. When the common-mode current flows through the stator core, it can generate a circumferential ring magnetic field, which can further induce a shaft voltage on the rotor shaft.

[0024] In this application, the term "common-mode voltage jump" can refer to the step change in common-mode voltage generated by inverter power devices (such as IGBTs or SiCMOSFETs) during switching operations. This jump is the main excitation source for common-mode current and resonant current.

[0025] In this application, the term "magnetically coupled shaft voltage" refers to the potential difference induced at both ends of the rotor shaft by a circumferential ring magnetic field in the stator core coupled through a magnetic circuit. The generation mechanism of this shaft voltage is as follows: a common-mode current generates a circumferential ring magnetic field in the yoke of the stator core. This magnetic field links to the rotor shaft. Due to the different magnetic reluctances at both ends of the rotor shaft within the magnetic circuit, a potential difference is formed at both ends of the rotor shaft. This shaft voltage is the voltage source for the subsequent formation of high-frequency loop currents.

[0026] In this application, the term "reference potential terminal" can refer to a low-potential terminal in an electric motor assembly that serves as a potential reference point. This reference potential terminal can be a motor housing (e.g., motor casing, end cover), system ground (e.g., grounding busbar of an electric drive system, vehicle body ground), or other potential terminal that can provide a low-impedance grounding path.

[0027] In this application, the term "resonant network" can refer to a circuit or combination of circuits used to generate a resonant current in a common-mode resonant conductor during a common-mode voltage transition. The resonant network may include at least one of resistive, inductive, and capacitive elements, and may have a series, parallel, or series-parallel combination topology. One end of the resonant network may be coupled to a second end of the common-mode resonant conductor, and the other end may be coupled to a reference potential terminal. The impedance characteristics of the resonant network (including resonant frequency and damping characteristics) can be configured to match the signal characteristics of the common-mode current.

[0028] In this application, the term "inner side of the stator core yoke" refers to the radially inner region of the body extending within the annular space enclosed by the stator core yoke. This region may include the bottom region of the stator slot or an axial channel specifically created inside the stator core yoke. When the common-mode resonant conductor extends along the motor axial direction within this region, its energizing current can induce a circumferential annular magnetic field in the stator core.

[0029] The following is combined with Figures 1 to 4 The electric motor device provided in this application will be further described below.

[0030] Figure 1 A schematic diagram is shown of the magnetic field generated by the common-mode current and its induced shaft voltage. (See diagram for example.) Figure 1 As shown, when the inverter outputs a high-frequency switching voltage, a common-mode current is induced in the windings. This common-mode current flows into the motor unit from the winding input terminal, and returns through the parasitic capacitance between the stator core and the housing. When the common-mode current flows through the stator core, it generates a circumferential ring magnetic field (denoted as the second circumferential ring magnetic field) in the yoke of the stator core. This second circumferential ring magnetic field passes through the stator yoke, air gap, and rotor core to form a closed magnetic circuit and links to the rotor shaft. Due to the different magnetic circuit positions and magnetic reluctances at the two ends of the rotor shaft in the magnetic field, this alternating second circumferential ring magnetic field induces a potential difference at the two ends of the rotor shaft, forming a magnetic field-coupled shaft voltage. Once this shaft voltage exceeds the insulation withstand voltage of the bearing oil film or the gear meshing surface contact point, it will break down the oil film, forming a high-frequency loop current, leading to electrolytic corrosion of the bearing raceway and gear surface.

[0031] Figure 2 A structural block diagram of a motor device for suppressing high-frequency loop currents according to some embodiments of this application is shown. The motor device may include a stator core, a rotor core, a rotor shaft, and windings. The windings are disposed on the stator core and have a neutral point. The motor device may also include a common-mode resonant conductor and a resonant network.

[0032] like Figure 2As shown, the first end of the common-mode resonant conductor is connected to the neutral point of the winding. The second end of the common-mode resonant conductor is connected to the reference potential terminal via a resonant network. The common-mode resonant conductor includes at least an axial segment extending along the axial direction of the motor assembly inside the stator core yoke. The resonant network is connected between the second end of the common-mode resonant conductor and the reference potential terminal.

[0033] The stator core may include a stator yoke and stator teeth. The rotor core is located radially inside the stator core, forming an air gap with it. The rotor shaft passes through the center of the rotor core and can rotate with it. The windings can be three-phase star windings, with the ends of the three phase windings connected to the neutral point. The input terminals of the windings (i.e., the beginning ends of the three phase windings) can be electrically connected to the three-phase output terminals of an external frequency converter.

[0034] In some implementations, the common-mode resonant conductor can be a single-turn conductor or a multi-turn parallel conductor composed of multiple turns of wire connected in parallel. The material of the common-mode resonant conductor can include copper, aluminum, or their alloys, or other conductive materials. The common-mode resonant conductor can have a circular, rectangular, or other shaped cross-section. An insulating layer can be provided on the outside of the common-mode resonant conductor to maintain electrical insulation between the common-mode resonant conductor and the stator core and windings.

[0035] In some implementations, the common-mode resonant conductor is led out from the neutral point of the winding, routed along the outside of the stator core to one axial end of the motor (e.g., the non-inlet end), enters the interior of the stator core from this end, and then runs axially within the stator core to the other axial end of the motor (e.g., the inlet end), where it is subsequently connected to the resonant network. This routing method avoids electrical interference between the common-mode resonant conductor and the inlet end of the winding, and facilitates access to the resonant network from outside the stator core.

[0036] In some embodiments, the portion of the common-mode resonant conductor extending axially within the stator core can be located inside the yoke of the stator core. Specifically, this inner side refers to the radially inner region of the annular space enclosed by the yoke of the stator core. Within this region, the common-mode resonant conductor can be arranged in several ways: one method is to place the common-mode resonant conductor within the stator slot of the stator core (in the same slot as the winding, ensuring sufficient insulation distance); another method is to specifically create an axial channel (e.g., an axial bore) inside the yoke of the stator core and pass the common-mode resonant conductor through this axial channel. Both methods ensure that the axial segment of the common-mode resonant conductor extends axially inside the yoke, thereby generating a circumferential annular magnetic field in the stator core when energized.

[0037] Figure 3 An exemplary circuit diagram of a resonant network according to some embodiments of this application is shown. Figure 3As shown, the resonant network can be an RLC series resonant circuit composed of a resistor, inductor, and capacitor. After the resistor, inductor, and capacitor are connected in series, one end is connected to the second end of the common-mode resonant conductor, and the other end is connected to the reference potential terminal. Figure 3 The diagram also shows a common-mode voltage jump source, which is the common-mode voltage excitation obtained by the common-mode resonant conductor from the neutral point.

[0038] When the common-mode voltage undergoes a step change in amplitude, the time-domain expression of the zero-state response current (i.e., resonant current) of the RLC series resonant circuit under step voltage excitation is: in, For time, The damping coefficient is... Let be the damped resonant angular frequency. Further, give... and The expression: , .

[0039] From the above expression, we can see that the oscillation angular frequency of the resonant current is... The decay time constant 1 / α (i.e., 2L / R) is determined by the inductance and capacitance, and is also determined by the resistance and inductance. Therefore, by configuring the inductance and capacitance values ​​of the resonant network, the following can be achieved: Even if the oscillation period of the resonant current is the same as the oscillation period of the common-mode current Equal; simultaneously, by configuring the resistance value of the resonant network, so that Even if the decay time constant of the resonant current is the same as the decay time constant of the common-mode current Equal. When the above two conditions are met simultaneously, the time-domain waveform of the resonant current and the time-domain waveform of the common-mode current are matched in terms of oscillation frequency and attenuation characteristics, thereby ensuring that the shaft voltage components induced at both ends of the rotor shaft can be precisely canceled at every moment, achieving the best suppression effect on high-frequency loop current.

[0040] It should be noted that the RLC series resonant circuit is only one exemplary implementation of the resonant network. The resonant network is not limited to the RLC series form and can also adopt other topologies composed of resistors, inductors, and capacitors (such as RLC in parallel, RL in series, RC in series, etc.). As long as the resonant network can generate a resonant current in the common-mode resonant conductor when the common-mode voltage changes, and the oscillation frequency and attenuation characteristics of the resonant current can match the common-mode current, it falls within the protection scope of this application.

[0041] Figure 4 A schematic diagram illustrating the principle of resonant current generating a reverse circumferential ring magnetic field in the stator core according to some embodiments of this application is shown. Figure 4As shown, when the common-mode voltage jumps, this jump voltage acts simultaneously on the circuit formed by the common-mode resonant conductor and the resonant network. The resonant network is excited by this jump voltage, generating a resonant current in the common-mode resonant conductor.

[0042] The resonant current flows from the neutral point of the winding, through the first end of the common-mode resonant conductor to the second end, and then through the resonant network to the reference potential end. When this resonant current flows in the axial section of the common-mode resonant conductor (located inside the yoke of the stator core), it generates a circumferential ring magnetic field in the stator core (denoted as the first circumferential ring magnetic field).

[0043] The direction of the first circumferential ring magnetic field is... Figure 1 The direction of the second circumferential ring magnetic field generated in the rotor is opposite. Specifically, since the axial segment of the common-mode resonant conductor is located inside the yoke of the stator core, its current direction is opposite to the direction of the equivalent axial component of the common-mode current in the winding. Therefore, according to the right-hand screw rule, the direction of the first circumferential ring magnetic field is opposite to the direction of the second circumferential ring magnetic field. This first circumferential ring magnetic field, with its opposite direction, also links to the rotor shaft and induces a shaft voltage component at both ends of the rotor shaft. This shaft voltage component is out of phase with the magnetic field-coupled shaft voltage induced by the common-mode current. The two components superimpose at both ends of the rotor shaft and cancel each other out, thereby significantly reducing the total shaft voltage at both ends of the rotor shaft and suppressing high-frequency loop current.

[0044] In some implementations, the axial section of the common-mode resonant conductor extends axially inside the yoke of the stator core in a specific routing direction from the non-inlet end of the motor assembly to the inlet end. This routing direction is opposite to the equivalent axial direction of the common-mode current in the winding (flowing from the inlet end to the non-inlet end), thereby ensuring that the directions of the first circumferential ring magnetic field and the second circumferential ring magnetic field are opposite.

[0045] In some embodiments, the motor may not require a separate external resonant network. A first end of the common-mode resonant conductor is connected to the neutral point of the winding, and a second end is directly connected to a reference potential terminal. The common-mode resonant conductor includes at least an axial segment extending along the axial direction of the motor assembly inside the stator core yoke. The parasitic capacitance, parasitic inductance, and parasitic resistance of the common-mode resonant conductor to the reference potential terminal are set to predetermined values, so that the common-mode resonant conductor generates a resonant current in the axial segment in response to a jump in the common-mode voltage in the winding, based on these predetermined parasitic parameters.

[0046] The preset parasitic parameters correspond to the physical parameters of the common-mode resonant conductor, which include one or more of the following: material, cross-sectional dimensions, number of parallel turns, and insulation layer thickness. The preset parasitic parameters also include one or more of the following: parasitic capacitance, parasitic inductance, and parasitic resistance. By adjusting these physical parameters, the parasitic parameters of the common-mode resonant conductor relative to the reference potential terminal can be configured to predetermined values, thereby enabling the common-mode resonant conductor to directly generate a resonant current when the common-mode voltage changes, without the need for external independent resistors, inductors, or capacitors.

[0047] In some embodiments, the axial segment is also configured such that the direction of the circumferential ring magnetic field generated in the stator core by the resonant current flowing through it is opposite to the direction of the circumferential ring magnetic field generated in the stator core by the common-mode current in the winding. Its working principle is the same as that of the embodiment with an independent resonant network, i.e., the resonant current flows axially in the axial segment, generating a reverse circumferential ring magnetic field in the stator core yoke, thereby canceling the magnetic field-coupled shaft voltage generated by the common-mode current. In some embodiments, the resonant frequency of the resonant network can be the same as the oscillation frequency of the common-mode current in the winding. In some embodiments, the decay time constant of the resonant network can be equal to the decay time constant of the common-mode current. The specific values ​​of the resistance, inductance, and capacitance of the resonant network can be theoretically calculated according to the formulas described above, or optimized through experimental tuning. For example, the values ​​can be obtained first from the measured waveform of the common-mode current. and Then select the one that satisfies and A combination of inductance, capacitance, and resistance. During experimental tuning, adjustable resistors, adjustable inductors, or adjustable capacitors can be used in the resonant network. By observing the change in the shaft voltage amplitude at both ends of the rotor shaft, the component parameters are gradually adjusted until the shaft voltage is suppressed to the lowest level.

[0048] In some implementations, the common-mode resonant conductor may include multiple conductor segments. For example, the common-mode resonant conductor may include a lead-out segment extending from the neutral point, an outer segment extending outside the stator core, an axial segment extending axially inside the stator core, and a lead-out segment extending from the stator core to the resonant network. The axial segment is the effective segment for generating the first circumferential ring magnetic field, while the remaining segments are primarily used for electrical connections. The length of the axial segment may be approximately equal to or slightly greater than the axial length of the stator core to fully utilize the yoke space of the stator core to generate the ring magnetic field.

[0049] In some implementations, the resonant network can be installed inside the motor junction box, outside the motor housing, or in a control cabinet adjacent to the motor. The second end of the common-mode resonant conductor is led out from inside the motor assembly and connected to the input terminal of the resonant network via an insulated wire. The reference potential terminal of the resonant network is connected to the motor housing or system ground via a grounding wire.

[0050] In some embodiments, the motor device can be a three-phase motor. In other embodiments, the motor device can also be a single-phase motor or a multi-phase motor (e.g., a six-phase or nine-phase motor). As long as the motor has a stator core, a rotor core, a rotor shaft, and windings with a neutral point (or a neutral point that can be artificially constructed), the technical solution of this application can be adopted.

[0051] In some embodiments, the motor can be a permanent magnet synchronous motor. In other embodiments, the motor can be an asynchronous motor (e.g., an induction motor) or a reluctance motor (e.g., a switched reluctance motor, a synchronous reluctance motor). Although the structural shapes and magnetic circuit characteristics of the stator core and rotor core differ for different types of motors, they all exhibit the physical phenomenon of common-mode current coupling to the rotor shaft through the stator core to generate shaft voltage. This application utilizes the core principle of generating a reverse ring magnetic field inside the yoke of the stator core using a common-mode resonant conductor to cancel the shaft voltage, which can be implemented in all the aforementioned types of motors.

[0052] In some implementations, the resonant network may include multiple switchable resistor, inductor, or capacitor branches to accommodate different common-mode current frequency ranges. For example, the oscillation frequency and decay time constant of the common-mode current may differ for different motor models or inverters with different switching frequencies. By setting switchable component branches, the same motor device can be adapted to various operating conditions, improving versatility.

[0053] In some implementations, the axial segment of the common-mode resonant conductor can be arranged as a multi-turn winding inside the yoke of the stator core. For example, the common-mode resonant conductor can be routed back and forth axially multiple times inside the yoke of the stator core to form a multi-turn structure. A multi-turn structure can generate a stronger first circumferential toroidal magnetic field at the same resonant current amplitude, thereby enhancing the cancellation effect on the shaft voltage. However, the multi-turn structure also increases the inductance and capacitance to ground of the common-mode resonant conductor, and its impact on the resonant frequency needs to be comprehensively considered during design.

[0054] In some implementations, multiple common-mode resonant conductors can be arranged circumferentially at intervals inside the yoke of the stator core. Each common-mode resonant conductor is led out from the neutral point of the winding and connected to a reference potential terminal via its respective resonant network. The multiple common-mode resonant conductors can be evenly distributed circumferentially to generate a more uniform first circumferential ring magnetic field distribution in the stator core. This implementation is particularly suitable for high-power motors or applications with strong common-mode interference.

[0055] This application also provides an electric drive system including the motor device described in any of the above embodiments. The electric drive system may include a frequency converter (e.g., an inverter) and a motor device, with the three-phase output terminals of the frequency converter electrically connected to the winding input terminals of the motor device. Because the motor device possesses a common-mode resonant conductor and a resonant network (or resonant conditions formed by the parasitic parameters of the common-mode resonant conductor itself), this electric drive system can effectively suppress high-frequency loop currents during operation, reduce the risk of bearing and tooth surface electro-corrosion, and improve system reliability and lifespan.

[0056] This application also provides a vehicle including the aforementioned electric drive system. The vehicle can be a pure electric vehicle, a hybrid electric vehicle, or other types of electric vehicles.

[0057] The aforementioned motor device, electric drive system, and vehicle have at least the following technical advantages: First, compared to existing technologies that use ceramic ball insulated bearings or common-mode filter magnetic rings, this application uses conventional electronic components such as resistors, capacitors, inductors, and wires, significantly reducing material costs. Second, this application avoids the use of ceramic ball bearings, eliminating the risk of ceramic rolling elements breaking under impact loads, thus providing greater robustness. Third, this application, through the special arrangement of common-mode resonant conductors on the motor stator, generates a resonant voltage at both ends of the motor shaft that is opposite in direction to the magnetic field-coupled shaft voltage, canceling the shaft voltage at its source. This effectively suppresses high-frequency loop currents, reduces electro-corrosion damage to the bearing raceways and tooth surfaces, lowers vibration and noise in the electric drive system, and extends the service life of the electric drive system.

[0058] Where applicable, the various embodiments provided in this application may be implemented using hardware, software, or a combination of hardware and software. Furthermore, where applicable, without departing from the scope of this application, the various hardware and / or software components described herein may be combined into composite components comprising software, hardware, and / or both. Where applicable, without departing from the scope of this application, the various hardware and / or software components described herein may be divided into sub-components comprising software, hardware, or both. Additionally, where applicable, it is contemplated that software components may be implemented as hardware components, and vice versa.

[0059] The software (such as program code and / or data) according to this application can be stored on one or more computer storage media. It is also contemplated that the software identified herein can be implemented using one or more networked and / or otherwise general-purpose or special-purpose computers and / or computer systems. Where applicable, the order of the various steps described herein can be changed, combined into compound steps, and / or divided into sub-steps to provide the features described herein.

[0060] The embodiments and examples presented herein are provided to best illustrate embodiments of this application and its particular applications, thereby enabling those skilled in the art to implement and use this application. However, those skilled in the art will understand that the above description and examples are provided for ease of illustration and example only. The descriptions presented are not intended to cover all aspects of this application or to limit this application to the precise forms disclosed.

Claims

1. A motor device, comprising a stator core, a rotor core, a rotor shaft, and a winding having a neutral point, characterized in that, The motor device also includes: A common-mode resonant conductor, the first end of which is connected to the neutral point, and the common-mode resonant conductor includes at least an axial segment extending along the axial direction of the motor device inside the stator core yoke. A resonant network, connected between the second end of the common-mode resonant conductor and the reference potential end, is used to generate a resonant current in the axial segment in response to a jump in the common-mode voltage in the winding; The axial segment is configured such that the direction of the circumferential annular magnetic field generated in the stator core by the resonant current flowing through it is opposite to the direction of the circumferential annular magnetic field generated in the stator core by the common-mode current in the winding.

2. The motor device according to claim 1, characterized in that, The axial section is disposed in the stator slot of the stator core, or in an axial channel opened on the stator core.

3. The motor device according to claim 1, characterized in that, After the common-mode resonant conductor is led out from the neutral point, it runs through the outside of the stator core to one end of the motor device in the axial direction, enters the stator core from the one end, and runs along the axial direction to the other end of the motor device in the axial direction.

4. The motor device according to claim 1, characterized in that, The common-mode resonant conductor is a single-turn conductor or a multi-turn parallel conductor composed of multiple turns of conductors connected in parallel.

5. The motor device according to claim 1, characterized in that, The resonant network includes one or more of the following elements: resistive elements, inductive elements, and capacitive elements.

6. The motor device according to claim 5, characterized in that, The component parameters of the resonant network are configured such that the resonant frequency of the resonant current is the same as the oscillation frequency of the common-mode current, and the decay time constant of the resonant current is equal to the decay time constant of the common-mode current.

7. A motor device comprising a stator core, a rotor core, a rotor shaft, and a winding having a neutral point, characterized in that, The motor device also includes a common-mode resonant conductor; The first end of the common-mode resonant conductor is connected to the neutral point, the second end is connected to the reference potential terminal, and the common-mode resonant conductor includes at least an axial segment extending along the axial direction of the motor device inside the stator core yoke. The common-mode resonant conductor is configured to generate a resonant current in the axial segment in response to a jump in the common-mode voltage in the winding, based on a preset parasitic parameter for the reference potential terminal. The axial segment is configured such that the direction of the circumferential annular magnetic field generated in the stator core by the resonant current flowing through it is opposite to the direction of the circumferential annular magnetic field generated in the stator core by the common-mode current in the winding.

8. The motor device according to claim 7, characterized in that, The preset parasitic parameters correspond to the physical parameters of the common-mode resonant conductor, wherein the physical parameters include one or more of the following: material, cross-sectional dimensions, number of parallel turns, and insulation layer thickness.

9. The motor device according to claim 8, characterized in that, The preset parasitic parameters include one or more of the following: parasitic capacitance, parasitic inductance, and parasitic resistance.

10. An electric drive system, characterized in that, Includes the motor device according to any one of claims 1 to 9.

11. A vehicle, characterized in that, Including the electric drive system according to claim 10.

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