Electric drive system and electric vehicle

Abstract

The present application discloses an electric drive system and an electric vehicle in the technical field of new energy vehicles. This electric drive system includes a motor and a bearing electric erosion suppression device. The motor includes a motor case, a bearing provided in the motor case, and a rotating shaft. The bearing electric erosion suppression device includes a capacitor module connected in series and a first resistance module. The input end of the bearing electric erosion suppression device is electrically connected to the rotating shaft, and the output end of the bearing electric erosion suppression device is grounded. The electric vehicle includes this electric drive system.

Description

Technical Field

[0001] (Related Application) This application claims the priority of Chinese patent applications with application numbers 202210763512.8 filed on June 30, 2022, and 202310483862.3 filed on April 28, 2023, and all of their contents are incorporated herein by reference.

[0002] This application relates to the technical field of new energy vehicles, and particularly to an electric drive system and an electric vehicle.

Background Art

[0003] The electric drive system of a new energy vehicle includes at least a drive motor and a motor controller. During the operation of the electric drive system, a common mode voltage and a high-frequency loop current are generated. Due to the voltage division effect of the floating capacitor in the electric drive system, the common mode voltage causes a voltage drop between the inner ring and the outer ring of the bearing. When the common mode shaft voltage exceeds the bearing oil film threshold voltage, the oil film is destroyed, and an EDM (Electrical Discharge Machining) discharge phenomenon appears, resulting in erosion on the surfaces of the inner and outer rings and the steel balls of the bearing, and spots appear. If EDM discharge is frequently performed for a long time, a distinct washboard pattern, that is, bearing electrical erosion, will appear on the surfaces of the inner and outer rings and the steel balls of the bearing, causing vibration and noise in the motor and affecting the operation of the motor.

[0004] In related technologies, in order to avoid the occurrence of bearing electrical erosion, a conductive ring or a conductive carbon brush is installed on the drive motor to form a conductive bypass. However, the problems existing in the currently adopted solutions are that the high-frequency loop currents of the motor end bearing and the reducer end bearing are relatively large, the high-frequency loop voltage generated at the reducer end bearing is relatively high, and the bearing electrical erosion phenomenon still exists.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The main object of the present application is to provide an electric drive system and an electric vehicle for solving the technical problem in the prior art that there is an electric erosion phenomenon of bearings in the motor of the electric drive system.

Means for Solving the Problem

[0006] To achieve the above object, the present application adopts the following technical solutions. According to a first aspect, the present application provides an electric drive system, which includes a motor case, a motor including a bearing and a rotating shaft provided in the motor case, a capacitor module connected in series, and a bearing electric erosion suppression device including a first resistance module. Here, the input end of the bearing electric erosion suppression device is electrically connected to the rotating shaft, and the output end of the bearing electric erosion suppression device is grounded.

[0007] In one embodiment, in the above electric drive system, the bearing electric erosion suppression device further includes a reactance module whose input end is connected to the first resistance module and whose output end is grounded.

[0008] In one embodiment, in the above electric drive system, the bearing electric erosion suppression device further includes a second resistance module connected in parallel to the capacitor module and the first resistance module connected in series, or connected in parallel to the capacitor module, the first resistance module and the reactance module connected in series.

[0009] In one embodiment, in the above electric drive system, the capacitor module includes a plurality of capacitors that are electrically connected, the first resistance module includes a plurality of resistors that are electrically connected, the reactance module includes a plurality of ferrite beads that are electrically connected and / or a plurality of inductances that are electrically connected, and the second resistance module includes a plurality of resistors that are electrically connected.

[0010] In one embodiment, in the above electric drive system, the electric drive system further includes a motor controller and a speed reducer that are electrically connected to the motor, wherein the bearing electric erosion suppression device is provided on the motor, the motor controller or the speed reducer.

[0011] In one embodiment, in the above electric drive system, the electric drive system further includes an insulating member, wherein the bearing is provided in the motor case, the bearing is fitted outside the rotating shaft, and the insulating member is provided between the bearing and the end cover of the motor.

[0012] In one embodiment, in the above electric drive system, the input end of the bearing electric erosion suppression device is electrically connected to the rotating shaft via a conductive bypass part.

[0013] In one embodiment, in the above electric drive system, the electric drive system further includes a speed reducer that is electrically connected to the motor, and the speed reducer includes a speed reducer shaft that is connected to the rotating shaft, wherein the input end of the bearing electric erosion suppression device is electrically connected to the speed reducer shaft via a conductive bypass part.

[0014] In one embodiment, in the above electric drive system, the electric drive system further includes a motor controller that is electrically connected to the motor, Here, the output end of the bearing electrolytic corrosion suppression device is electrically connected to the motor case, and the motor case is grounded, or the output end of the bearing electrolytic corrosion suppression device is electrically connected to the case of the motor controller, and the case of the motor controller is grounded.

[0015] According to a second aspect, the present application provides an electric vehicle, which includes a battery, and the electric drive system as described above, wherein the battery is used to provide electrical energy to the electric drive system.

Advantages of the Invention

[0016] One or more of the technical solutions according to the present application can have the following advantages, or at least achieve the following technical effects, that is, According to the electric drive system and the electric vehicle according to the present application, the electric drive system includes a motor and a bearing electrolytic corrosion suppression device, the rotating shaft of the motor is grounded through the bearing electrolytic corrosion suppression device, and the bearing electrolytic corrosion suppression device in which the capacitor module and the first resistance module are configured in series can reduce the common mode voltage of the inner and outer rings of the bearing, avoid the oil film being destroyed and EDM discharge occurring when the voltage of the inner and outer rings is too high, and have the effect of suppressing the electrolytic corrosion of the bearing. In addition, the capacitor module and the first resistance module connected in series can suppress the high-frequency loop current, avoid the influence of the shaft current on the bearing, and have the effect of extending the service life of the bearing.

[0017] To more clearly explain the technical solutions in the embodiments of the present application or the prior art, the drawings required to be used in the description of the embodiments or the prior art are briefly introduced below. The drawings in the following description are only some embodiments of the present application, and it is obvious that those skilled in the art can obtain other drawings based on these provided drawings without creative labor.

Brief Description of the Drawings

[0018]

Figure 1

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Figure 13

Embodiments for Carrying Out the Invention

[0019] Regarding the realization of the object, functional features and advantages of the present application, further description will be given with reference to the drawings in combination with the embodiments.

[0020] To make the objectives, technical solutions and advantages of the present application clearer, the following provides a clear and complete description of the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. It is obvious that the described embodiments are only a part of the embodiments of the present application, not all of them. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present invention.

[0021] It should be noted that in the embodiments of the present application, all directional indications (such as up, down, left, right, front, back, etc.) are only used for the interpretation of the relative positional relationship and movement status between various components in a specific posture (as shown in the drawings). When this specific posture changes, the directional indications will change accordingly. In the present application, the terms "include", "comprise" or any other arbitrary variations are intended to cover non-exclusive "inclusion". A process, method, article or system that includes a series of elements not only includes those elements, but also includes other elements that are not explicitly listed, or further includes elements specific to such a process, method, article or system. In the case of no further limitations, the presence of other same elements in the process, method, article or system that includes the element limited by the phrase "comprising..." is not excluded. In the present application, unless there are separate clear regulations and limitations, terms such as "connection" and "fixation" should be understood in a broad sense. For example, "connection" may be a fixed connection, a removable connection, or an integral one, and may be a mechanical connection, an electrical connection, a direct connection, an indirect connection through an intermediate medium, or a communication inside two elements or an interaction relationship between two elements. In the present application, if there are descriptions regarding "first", "second", etc., these descriptions of "first", "second", etc. should only be used for the purpose of the description, and should not be understood as indicating or implying their relative importance, or implicitly indicating the number of the indicated technical features. Thus, the features limited by "first" and "second" can explicitly or implicitly include at least one such feature. In the present application, the use of suffixes such as "module", "component", or "unit" to represent elements is only for the convenience of the description of the present application and has no specific meaning in itself. Therefore, "module", "component", or "unit" can be used in combination.

[0022] Those skilled in the art can understand the specific meanings of the above terms in this application according to specific circumstances. In addition, the technical solutions of each embodiment may be combined with each other, but based on what can be realized by those skilled in the art, if the combination of technical solutions conflicts with each other or cannot be realized, such a combination of technical solutions does not exist and should be regarded as outside the protection scope required by this application.

[0023] The electric drive system of a new energy vehicle includes at least a driving motor and a motor controller. During the operation of the electric drive system, the PWM signal wave output by the motor controller generates a common-mode voltage between the midpoint of the DC bus and the midpoint of the three-phase windings of the driving motor, and at the same time, due to the high-speed on-off characteristics of the switch device in the motor controller, a high dv / dt value is generated. This dv / dt value and the coupling capacitor between the stator winding and the housing jointly cause a high-frequency common-mode current. This high-frequency common-mode current excites a circular common-mode magnetic flux in the core, induces an axial voltage on the rotating shaft, and generates a high-frequency loop current. Under the combined action of the common-mode voltage and the high-frequency loop current, the bearings at the motor end, the bearings at the non-driving end of the reducer, and the bearings at the driving end of the reducer are all easily damaged.

[0024] Due to the voltage division effect of the floating capacitor in the electric drive system, the common-mode voltage causes a voltage drop between the inner ring and the outer ring of the bearing. When the common-mode axial voltage exceeds the bearing oil film threshold voltage, the oil film is destroyed, an EDM discharge phenomenon appears, and erosion occurs on the surfaces of the inner and outer rings of the bearing and the steel balls, resulting in spots. If EDM discharge is frequently performed for a long time, a distinct washboard pattern, that is, bearing electrical erosion, will appear on the surfaces of the inner and outer rings of the bearing and the steel balls, causing vibration and noise in the motor and affecting the operation of the motor.

[0025] In related technologies, in order to avoid the occurrence of bearing electrical erosion, a conductive ring or a conductive carbon brush is installed on the driving motor to form a conductive bypass. Generally, there are the following solutions: 1. Install an insulated bearing at the motor end and make the driving end of the reducer conduct electricity at one end. 2. Install insulated bearings at the non-driving end and the driving end of the reducer respectively, and make the motor end conduct electricity at one end. 3. Install insulated bearings at the motor end and the non-driving end of the reducer respectively, and make the motor end conduct electricity at one end.

[0026] The above solutions mainly relate to the suppression of bearing electrolytic corrosion of 400V high-voltage silicon (Si) products. With the progress and application of silicon carbide (SiC) technology, the dv / dt value becomes higher, and the generated high-frequency loop current also becomes larger accordingly. The problems existing in the above solutions are that the high-frequency loop currents of the motor-end bearing and the reducer-end bearing are relatively large, the high-frequency loop voltage generated at the reducer-end bearing is relatively high, and the phenomenon of bearing electrolytic corrosion still exists. Moreover, here, it is difficult to ensure the sealing performance of the conductive ring that realizes conduction at one end, which also affects the conduction effect. In related technologies, there is currently no effective solution for suppressing bearing electrolytic corrosion of 800V silicon carbide (SiC) products.

[0027] In the prior art, there is a phenomenon of bearing electrolytic corrosion in the motor. In view of the technical problem that the current technology cannot effectively suppress bearing electrolytic corrosion, the present application provides an electric drive system and an electric vehicle. Hereinafter, in combination with the drawings, the electric drive system according to the present application will be described in detail by specific examples and embodiments.

[0028] Embodiment 1 Referring to FIG. 2, a first embodiment of the electric drive system of the present application is proposed. This electric drive system may include a motor and a bearing electrolytic corrosion suppression device.

[0029] The motor may include a motor case, a bearing provided within the motor case, and a rotating shaft. The inner ring of the bearing is connected to the rotating shaft, and the outer ring of the bearing is connected to the motor case. The motor may further include a rotor and a stator. The stator includes components and parts such as a stator core and a stator winding. Additionally, the motor may include components and parts such as, for example, a spline and a position sensor. Since the structure of the motor is a technical solution known in this field, it will not be described further herein.

[0030] As shown in FIG. 1, it is a common-mode equivalent circuit of an electric drive system in the prior art. Specifically, there is a floating capacitor C in the bearing of the motor b and there is a coupling capacitor C sr between the stator core and the rotor, there is a coupling capacitor C wr between the stator winding and the rotor, there is a coupling capacitor C wf between the stator winding and the stator, and there is a floating capacitor C g between the bearing on the speed reducer side and the spline.

[0031] At the moment of the high-speed opening and closing of the switch device in the motor controller, the generated high dv / dt value and the coupling capacitor jointly cause a high-frequency common-mode current. This high-frequency common-mode current excites an annular common-mode magnetic flux in the core, induces a common-mode shaft voltage on the rotating shaft, and generates a high-frequency loop current.

[0032] Regarding the problem of electric erosion of the bearing of the motor, based on the principle of the generation of the common-mode shaft voltage and the high-frequency loop current, this embodiment provides an electric drive system including a bearing electric erosion suppression device. The input end of this bearing electric erosion suppression device is electrically connected to the rotating shaft of the motor in the electric drive system. The output end of this bearing electric erosion suppression device is grounded. This bearing electric erosion suppression device may be connected in parallel to the bearing in the motor. Specifically, it may be connected in parallel to the floating capacitor C b of the bearing. This bearing electrolytic corrosion suppression device is used to suppress the high-frequency loop current generated in the bearing. This bearing electrolytic corrosion suppression device may include a capacitor module connected in series and a first resistance module.

[0033] In the electric drive system of this embodiment, the input end of the bearing electrolytic corrosion suppression device is electrically connected to the rotating shaft of the motor, and the output end is grounded. That is, the rotating shaft of the motor realizes grounding through this bearing electrolytic corrosion suppression device. Specifically, the input end of the capacitor module is electrically connected to the rotating shaft of the motor, the output end of the capacitor module is connected to the input end of the first resistance module, and the output end of the first resistance module is grounded as the output end of the bearing electrolytic corrosion suppression device.

[0034] When this bearing electrolytic corrosion suppression device is applied to the electric drive system according to this embodiment, the equivalent circuit diagram of the electric drive system is composed of a capacitor module and a first resistance module connected in series to form this bearing electrolytic corrosion suppression device as shown in FIG. 2. It should be noted that the capacitor module may be realized by one capacitor, or may be realized by a plurality of capacitors connected in series and / or in parallel. The first resistance module may be realized by one resistor, or may be realized by a plurality of resistors connected in series and / or in parallel. For example, in this embodiment, the capacitor module is realized by one capacitor C d and the first resistance module is realized by one resistor R d and the capacitor C d connected in series and the resistor R d constitute this bearing electrolytic corrosion suppression device. In specific applications, it can be selected according to actual needs and is not limited here.

[0035] As shown in FIG. 2, the capacitor C d connected in series and the resistor R d are the floating capacitor C bis connected in parallel, divides the voltages of the inner and outer rings of the bearing, reduces the common-mode voltage of the inner and outer rings of the bearing, and avoids causing electric corrosion to the bearing by preventing the oil film from being destroyed and EDM discharge from occurring when the voltages of the inner and outer rings are too high.

[0036] According to the following formula,

Equation

Equation

Equation

Equation

[0037] of the inner and outer rings of the bearing also decreases. d In this embodiment, the capacitor C b of the bearing electric corrosion suppression device is connected in parallel to the bearing of the motor, so as to perform voltage division on the voltage between the inner ring and the outer ring of the bearing, adjust the voltage division ratio, and reduce the common-mode voltage V d of the inner and outer rings of the bearing, and avoid causing electric corrosion to the bearing by preventing the oil film from being destroyed and EDM discharge from occurring when the voltages of the inner and outer rings are too high. The resistor R dBy being connected in series, the loop current can be reduced, and the influence of the differential mode voltage on the bearing can be avoided. In an electric drive system, the capacitor module and the first resistance module in the bearing electrolytic corrosion suppression device are connected in series, and electromagnetic interference generated by exceeding the EMI standard due to instantaneous high-frequency radio waves during charging and discharging can be avoided.

[0038] In the electric drive system according to this embodiment, the rotating shaft of the motor is grounded through the bearing electrolytic corrosion suppression device, and the bearing electrolytic corrosion suppression device configured by being connected in series by the capacitor module and the first resistance module can reduce the common mode voltage of the inner and outer rings of the bearing, and avoid the oil film being destroyed and EDM discharge occurring when the voltage of the inner and outer rings is too high, so as to have the effect of suppressing the electrolytic corrosion of the bearing. In addition, the capacitor module and the first resistance module connected in series can suppress the high-frequency loop current, avoid the influence of the shaft current on the bearing, and can have the effect of extending the service life of the bearing.

[0039] Embodiment Two Based on the same inventive concept, referring to FIG. 3 and based on Embodiment One, a second embodiment of the electric drive system of the present application is proposed.

[0040] Furthermore, in this electric drive system, the bearing electrolytic corrosion suppression device may further include a reactance module whose input end is connected to the first resistance module and whose output end is grounded.

[0041] That is, the bearing electrolytic corrosion suppression device in this embodiment is a capacitor module, a first resistance module and a reactance module connected in series.

[0042] In a specific embodiment, the bearing electrolytic corrosion suppression device has an input end electrically connected to the rotating shaft of the motor and an output end grounded. That is, the input end of the capacitor module is electrically connected to the rotating shaft of the motor, the output end of the capacitor module is connected to the input end of the reactance module via the first resistance module, and the output end of the reactance module is grounded as the output end of the bearing electrolytic corrosion suppression device.

[0043] When this bearing electrolytic corrosion suppression device is applied to the electric drive system according to this embodiment, as shown in FIG. 3, the equivalent circuit diagram of the electric drive system shows that the capacitor module, the first resistance module, and the reactance module connected in series constitute this bearing electrolytic corrosion suppression device. It should be noted that the reactance module may include inductance and / or ferrite beads. The reactance module may be realized by one inductance, or may be realized by a plurality of inductances connected in series and / or in parallel. It may be realized by one ferrite bead, or may be realized by a plurality of ferrite beads connected in series and / or in parallel. Furthermore, the reactance module may be realized by connecting one or more inductances and one or more ferrite beads in series and / or in parallel. For example, the reactance module in this embodiment is realized by one ferrite bead FB d and the capacitor C connected in series d , resistance R d and ferrite bead FB d constitute this bearing electrolytic corrosion suppression device. In specific applications, it can be selected according to actual needs and is not limited here.

[0044] As shown in FIG. 3, the capacitor C connected in series d , resistance R d and ferrite bead FB d are the floating capacitor C of the bearing bis connected in parallel, divides the voltages of the inner and outer rings of the bearing, and can avoid causing electrolytic corrosion to the bearing by preventing the oil film from being destroyed and EDM discharge from occurring when the voltages of the inner and outer rings are too high. The ferrite bead FB d is the resistor R d and the capacitor C d are connected in series. By utilizing the characteristics of low-frequency and low-resistance, and high-frequency and high-resistance of the ferrite bead, the high-frequency loop current can be effectively reduced. At the same time, when the frequency is low, it does not affect the increase of the common-mode voltage V b between the inner and outer rings of the bearing, and when the frequency is high, the influence of the differential-mode voltage on the bearing can be avoided.

[0045] The electric drive system according to this embodiment not only has the beneficial effects of the electric drive system according to the first embodiment, but also can effectively reduce the high-frequency loop current due to the high-frequency and high-impedance characteristics of the reactance module. At the same time, it can enable the electric drive system to cope with the influence caused by generating a larger high-frequency loop current due to the characteristic of the high dv / dt value of the silicon carbide switch device.

[0046] Embodiment Three Based on the same inventive concept, referring to FIG. 4 and based on the first embodiment, a third embodiment of the electric drive system of the present application is proposed.

[0047] In order to further discharge the charge of the motor's rotating shaft to the ground, in this electric drive system, the bearing electrolytic corrosion suppression device may further include a capacitor module connected in series and a second resistor module connected in parallel with the first resistor module.

[0048] That is, the bearing electrolytic corrosion suppression device in this embodiment has two circuits. One circuit is a capacitor module and a first resistor module connected in series, and the other circuit is a single second resistor module.

[0049] In a specific embodiment, the bearing electrolytic corrosion suppression device has an input end electrically connected to the rotating shaft of the motor and an output end grounded. That is, both the input end of the capacitor module and the input end of the second resistor module are electrically connected to the rotating shaft of the motor. The output end of the capacitor module is connected to the input end of the first resistor module, and the output ends of the first resistor module and the second resistor module are connected in parallel and grounded as the output end of the bearing electrolytic corrosion suppression device.

[0050] When this bearing electrolytic corrosion suppression device is applied to the electric drive system according to this embodiment, the equivalent circuit diagram of the electric drive system is as shown in FIG. 4. When the second resistor module is connected in parallel to the capacitor module and the first resistor module connected in series, this bearing electrolytic corrosion suppression device is constituted.

[0051] In this embodiment, by connecting the second resistor module in parallel to the capacitor module and the first resistor module connected in series, the charge to the ground of the rotating shaft of the motor can be further discharged to assist in reducing the shaft voltage.

[0052] Specifically, the capacitor module may be realized by one capacitor, or may be realized by a plurality of capacitors connected in series and / or in parallel. The first resistor module may be realized by one resistor, or may be realized by a plurality of resistors connected in series and / or in parallel. The second resistor module may also be realized by one resistor, or may be realized by a plurality of resistors connected in series and / or in parallel. In specific applications, the number of each electronic component can be adjusted according to actual needs and is not limited here.

[0053] For example, the capacitor module in this embodiment adopts one capacitor C b and the first resistor module adopts one resistor R d and the second resistor module adopts one resistor R e As shown in FIG. 4, the resistor R e is connected in parallel to the capacitor C dand resistor R d By being connected in parallel thereto, a bearing electrolytic corrosion suppression device for the electric drive system in the present embodiment is configured.

[0054] In one embodiment, the capacitor module may include a plurality of capacitors that are electrically connected, the first resistor module may include a plurality of resistors that are electrically connected, and the second resistor module may include a plurality of resistors that are electrically connected.

[0055] Here, the above electrical connection may include a series and / or parallel connection. Specifically, it includes that a plurality of electronic components are connected in series, a plurality of electronic components are connected in parallel, a plurality of groups of electronic components are connected in series or a plurality of groups of electronic components are connected in parallel, but is not limited thereto. Here, a group of electronic components is a plurality of electronic components connected in series or a plurality of electronic components connected in parallel, and specifically, it can be provided according to the actual situation and is not limited here.

[0056] By the above installation, by freely adjusting the magnitude of the capacitance value of the capacitor module or the magnitude of the resistance values of the first resistor module and the second resistor module, the needs of different model products can be satisfied and a wide adaptability can be enhanced. Also, so that this bearing electrolytic corrosion suppression device achieves an optimal suppression effect, an electrical connection method can be selected according to the actual needs, the number of electronic components can be provided according to the actual needs, and the parameters of the device can be adjusted according to the actual needs.

[0057] In one embodiment, as shown in FIG. 5, it is an equivalent circuit diagram of the bearing electrolytic corrosion suppression device in the present embodiment, and a resistor R e is the second resistor module in the bearing electrolytic corrosion suppression device, and a resistor R d is the first resistor module, and the capacitor module C d may be composed of a capacitor C1 and a capacitor C2 connected in parallel. This resistor R e resistor R dThe electric circuit composed of capacitor C1 and capacitor C2 can achieve grounding by connecting one side to the rotating shaft and the other side to the motor housing.

[0058] In this embodiment, resistor R d One electric circuit of the circuit composed of capacitor C1 and capacitor C2 can be used to suppress the common-mode voltage acting on the inner and outer rings of the bearing and reduce the fluctuation amplitude of the differential-mode voltage. Here, the two capacitors C1 and C2 connected in parallel can adjust the phase and amplitude of the differential-mode voltage to assist in reducing the shaft voltage. On the other hand, resistor R e The other electric circuit composed of can achieve the discharge of the charge of the rotating shaft of the motor to the ground.

[0059] The electric drive system according to this embodiment not only has the beneficial effects of the electric drive system according to the first embodiment, but also can discharge the common-mode charge and reduce the electromagnetic interference caused by high-frequency radio waves during charging and discharging. At the same time, by connecting a plurality of capacitors in series / parallel to form a capacitor module and connecting a plurality of resistors in series / parallel to form a first resistor module and a second resistor module, the magnitude of the capacitance value of the capacitor module and the magnitude of the resistance values of the first resistor module and the second resistor module can be freely adjusted, having higher adaptability and enabling the bearing electric erosion suppression device to achieve an optimal suppression effect.

[0060] Embodiment Four Based on the same inventive concept, referring to FIG. 6 and based on Embodiment Two, a fourth embodiment of the electric drive system of the present application is proposed.

[0061] In order to further discharge the charge of the rotating shaft of the motor to the ground, the bearing electric erosion suppression device in this electric drive system It may further include a capacitor module connected in series, a first resistance module, and a second resistance module connected in parallel with the reactance module.

[0062] That is, the bearing electrolytic corrosion suppression device in this embodiment has two circuits. One circuit is a capacitor module, a first resistance module, and a reactance module connected in series, and the other circuit is a single second resistance module.

[0063] In a specific embodiment, the input end of the bearing electrolytic corrosion suppression device is electrically connected to the rotating shaft of the motor, and the output end is grounded. That is, both the input end of the capacitor module and the input end of the second resistance module are electrically connected to the rotating shaft of the motor. The output end of the capacitor module is connected to the input end of the reactance module through the first resistance module. The output end of the reactance module and the output end of the second resistance module are connected in parallel and grounded as the output end of the bearing electrolytic corrosion suppression device.

[0064] When this bearing electrolytic corrosion suppression device is applied to the electric drive system according to this embodiment, the equivalent circuit diagram of the electric drive system is as shown in FIG. 6. When the second resistance module is connected in parallel with the capacitor module, the first resistance module, and the reactance module connected in series, this bearing electrolytic corrosion suppression device is constituted.

[0065] In this embodiment, by connecting the second resistance module in parallel with the capacitor module, the first resistance module, and the reactance module connected in series, the charge to the ground of the rotating shaft of the motor can be further discharged to assist in reducing the shaft voltage.

[0066] Specifically, the capacitor module may be realized by one capacitor, or may be realized by a plurality of capacitors connected in series and / or in parallel. The first resistor module may be realized by one resistor, or may be realized by a plurality of resistors connected in series and / or in parallel. The second resistor module may also be realized by one resistor, or may be realized by a plurality of resistors connected in series and / or in parallel. The reactance module may be realized by one inductance, or may be realized by a plurality of inductances connected in series and / or in parallel. The reactance module may also be realized by one ferrite bead, or may be realized by a plurality of ferrite beads connected in series and / or in parallel. Furthermore, the reactance module may be realized by connecting one or more inductances and one or more ferrite beads in series and / or in parallel. In specific applications, the number of each electronic component can be adjusted according to actual needs and is not limited here.

[0067] For example, the capacitor module in this embodiment adopts one capacitor C d The first resistor module adopts one resistor R d The reactance module adopts one ferrite bead FB d The second resistor module adopts one resistor R e As shown in FIG. 6, the resistor R e is connected in parallel to the capacitor C d connected in series, the resistor R d and the ferrite bead FB d to constitute the bearing electrolytic corrosion suppression device of the electric drive system in this embodiment.

[0068] In one embodiment, the capacitor module may include several capacitors that are electrically connected, the first resistance module may include several resistances that are electrically connected, the reactance module may include several ferrite beads that are electrically connected and / or several inductances that are electrically connected, and the second resistance module may include several resistances that are electrically connected.

[0069] Here, the above electrical connection may include series and / or parallel connections. Specifically, it includes that several electronic components are connected in series, several electronic components are connected in parallel, several groups of electronic components are connected in series or several groups of electronic components are connected in parallel, but is not limited thereto. Here, a group of electronic components is several electronic components connected in series or several electronic components connected in parallel. The specific connection method can be provided according to the actual situation and is not limited here.

[0070] By the above installation, by freely adjusting the magnitude of the capacitance value of the capacitor module, the characteristics of the reactance module or the magnitude of the resistance values of the first resistance module and the second resistance module, the needs of different model products can be met and a wide adaptability can be enhanced. Also, in order for this bearing electrolytic corrosion suppression device to achieve an optimal suppression effect, an electrical connection method can be selected according to actual needs, the number of electronic components can be provided according to actual needs, and the parameters of the device can be adjusted according to actual needs.

[0071] In one embodiment, as shown in FIG. 7, it is an equivalent circuit diagram of the bearing electrolytic corrosion suppression device in this embodiment, and a resistance R e is the second resistance module in the bearing electrolytic corrosion suppression device, and a resistance R d is the first resistance module, and one ferrite bead FB d is the reactance module in the bearing electrolytic corrosion suppression device, and the capacitor module C d may be composed of a capacitor C1 and a capacitor C2 connected in parallel. This resistance R e resistance Rd , Ferrite bead FB d The electric circuit composed of capacitor C1 and capacitor C2 can achieve grounding by connecting one side to the rotating shaft and the other side to the motor housing.

[0072] In this embodiment, resistor R d , Ferrite bead FB d The electric circuit of one circuit composed of capacitor C1 and capacitor C2 may be used to suppress the common-mode voltage acting on the inner and outer rings of the bearing and reduce the fluctuation amplitude of the differential-mode voltage. Here, the two capacitors C1 and C2 connected in parallel can adjust the phase and amplitude of the differential-mode voltage to assist in reducing the shaft voltage. Resistor R e The electric circuit of the other circuit composed of can achieve the discharge of the charge of the rotating shaft of the motor to the ground.

[0073] The electric drive system according to this embodiment not only has the beneficial effects of the electric drive system according to the second embodiment, but also can discharge the common-mode charge and reduce the electromagnetic interference caused by high-frequency radio waves during charging and discharging. At the same time, a plurality of capacitors are connected in series / parallel to form a capacitor module, a plurality of inductances and / or ferrite beads are connected in series / parallel to form a reactance module, and a plurality of resistors are connected in series / parallel to form a first resistor module and a second resistor module. By doing so, the magnitude of the capacitance value of the capacitor module, the characteristics of the reactance module, and the magnitude of the resistance values of the first resistor module and the second resistor module can be freely adjusted, having higher adaptability, and enabling the bearing electric erosion suppression device to achieve an optimal suppression effect.

[0074] Embodiment Five Based on the same inventive concept, referring to FIG. 8, a fifth embodiment of the electric drive system of the present application is proposed based on any one of Embodiments One to Four.

[0075] Furthermore, as shown in FIG. 8, it is a schematic diagram of the structure of the bearing electrolytic corrosion suppression device. The bearing electrolytic corrosion suppression device of the electric drive system is It may further include a PCB board 60 (Printed Circuit Board), and the capacitor module, the first resistance module, the reactance module, and the second resistance module may all be provided on the PCB board 60.

[0076] Specifically, the capacitor module, the first resistance module, the reactance module, and the second resistance module may form the structures of different electric circuits adopted in any of the above-mentioned first to fourth embodiments, and correspondingly, they are provided in the electronic component module 10. When the bearing electrolytic corrosion suppression device includes a capacitor module and a first resistance module, the electronic component module 10, that is, the capacitor module and the first resistance module, will be provided on the PCB board 60. When the bearing electrolytic corrosion suppression device includes a capacitor module, a first resistance module, and a reactance module, the electronic component module 10, that is, the capacitor module, the first resistance module, and the reactance module, will be provided on the PCB board 60. When the bearing electrolytic corrosion suppression device includes a capacitor module, a first resistance module, and a second resistance module, the electronic component module 10, that is, the capacitor module, the first resistance module, and the second resistance module, are all provided on the PCB board 60, or the capacitor module and the first resistance module are provided on the PCB board 60, but the second resistance module is provided at a position other than the PCB board 60. When the bearing electrolytic corrosion suppression device includes a capacitor module, a first resistance module, a reactance module, and a second resistance module, the electronic component module 10, that is, the capacitor module, the first resistance module, the reactance module, and the second resistance module, are all provided on the PCB board 60, or the capacitor module, the first resistance module, and the reactance module are provided on the PCB board 60, but the second resistance module is provided at a position other than the PCB board 60. In specific applications, it can also be provided according to actual needs.

[0077] Furthermore, as shown in FIG. 8, the bearing electrolytic corrosion suppression device for an electric drive system includes: The electronic device may further include a support 90 provided below the PCB board 60 in which the electrical connection fixing holes 61 are provided.

[0078] Specifically, the support 90 may be a member made of a plastic material and plays an insulating role. The conductive bypass part 70 may be fixed to the support 90 through an electrical connection fixing hole 61 in the PCB board 60 via a screw, so as to realize an electrical connection between the conductive bypass part 70 and each device in the electronic component module 10 in the bearing electrolytic corrosion suppression device. The PCB board 60 may be grounded, for example, through another electrical connection fixing hole 61 in the PCB board 60 via a screw, and connected to a rotary transformer cover plate, case, etc. of a motor. When the input end of the bearing electrolytic corrosion suppression device is electrically connected to the rotating shaft 30 of the motor in the electric drive system, the rotor current is guided to the PCB board 60 via the conductive bypass part 70, and the current flows through the electronic component module 10 in the bearing electrolytic corrosion suppression device to the ground end or case.

[0079] Furthermore, as shown in FIG. 9, which is a structural schematic diagram of the electric drive system in this embodiment, the electric drive system includes: The motor controller and the reducer may be electrically connected to the motor. Here, the bearing electrical corrosion suppression device may be provided in a motor, a motor controller, or a reducer.

[0080] Specifically, the bearing electrolytic corrosion suppression device may be mounted on the non-driving end of the motor, or may be mounted inside the motor controller or reducer, and is integrated with the conductor of the position sensor 80 to guide the current to the motor controller case. In this embodiment, the mounting position of the bearing electrolytic corrosion suppression device is not limited.

[0081] Furthermore, the reducer may further include a reducer shaft connected to the rotating shaft 30.

[0082] During specific implementation, the bearing electric erosion suppression device can achieve electrical connection with the rotating shaft 30 through the conductive bypass part 70, or can be electrically connected to the reduction gear shaft through the conductive bypass part 70. Since the reduction gear shaft is connected to the rotating shaft 30, at this time, this bearing electric erosion suppression device, that is, can achieve electrical connection with the rotating shaft 30 through the reduction gear shaft. Optionally, the conductive bypass part 70 can be any one of a conductive carbon brush, a conductive ring, a conductive elastic piece, a conductive brush, etc.

[0083] In this embodiment, the input end of the bearing electric erosion suppression device can be electrically connected to the rotating shaft 30 through the conductive bypass part 70, or can be electrically connected to the reduction gear shaft through the conductive bypass part 70. However, the output end of the bearing electric erosion suppression device is grounded. Specifically, it can be directly grounded, or grounding can be achieved through the motor case of the motor, or grounding can be achieved through the reduction gear case of the reduction gear, or grounding can be achieved through the motor controller case of the motor controller. Here, the output end of the bearing electric erosion suppression device realizes grounding through the motor case. Specifically, it is electrically directly connected to the motor case in the electric drive system, the motor case is grounded, the output end of the bearing electric erosion suppression device realizes grounding through the reduction gear case. Specifically, it is electrically directly connected to the reduction gear case in the electric drive system, the reduction gear case is grounded, the output end of the bearing electric erosion suppression device realizes grounding through the motor controller case. Specifically, it is electrically directly connected to the motor controller case in the electric drive system, and the motor controller case is grounded.

[0084] Furthermore, in order to cut off the current path of the high-frequency loop current in the electric drive system, by adding insulation treatment to the non-driving end, it is possible to avoid the bearings of the driving motor and the reduction gear bearings in the electric drive system being affected by the shaft current, and thus, the service life of the bearings can be extended.

[0085] In one embodiment, as shown in FIG. 9, this electric drive system may further include an insulating member 50. The bearing 40 is provided in the motor case, the bearing 40 is fitted outside the rotating shaft 30, and the insulating member 50 is provided between the bearing 40 and the end cover 20 of the motor.

[0086] Specifically, the material of the insulating member 50 may be high-strength plastic. The shape of the insulating member 50 may be an insulating ring. The insulating ring may be mounted outside the motor bearing 40. The inner wall of the insulating ring may contact the outer ring of the bearing 40, and the outer wall of the insulating ring may contact the inner wall of the end cover 20. The insulating ring may be mounted between the bearing 40 and the end cover 20 to cut off the bearing 40 from the case.

[0087] As shown in FIGS. 8 and 9, the bearing electric erosion suppression device is electrically connected to the rotating shaft 30 of the motor via a conductive bypass part 70. The insulating member 50 is provided between the bearing 40 and the end cover 20 of the motor. The inner wall of the insulating member 50 abuts against the outer wall of the bearing 40, and the outer wall of the insulating member 50 abuts against the inner wall of the motor end cover 20. The motor end cover 20 is a part of the motor case. The insulating member 50 can be used to cut off the bearing 40 from the motor case. At this time, in the equivalent circuit of the electric drive system, as shown in FIG. 4 or FIG. 6, when the insulating member 50 is added, the floating capacitor C of the insulating member 50 a also divides the voltage of the bearing 40, further improving the suppression effect on the shaft current.

[0088] In another embodiment, the bearing 40 of the electric drive system may be an insulated bearing, and the end cover 20 may be an insulated end cover. By coating an insulating coating layer on the surface of the bearing 40, the outer ring of the bearing 40 may be insulated, or the bearing 40 may be made directly of an insulating material. Similarly, the insulated end cover may be coated with an insulating coating layer or made directly of an insulating material. It should be noted that in the electric drive system, an insulated bearing and an insulated end cover may be employed simultaneously, or an insulated bearing or an insulated end cover may be employed alone. Furthermore, on the basis of employing an insulated bearing or an insulated end cover, an insulating member 50 may be added between the bearing 40 and the end cover 20. The end cover 20 of the motor is part of the motor case.

[0089] Adding a bearing electric erosion suppression device and insulation treatment to the electric drive system can also suppress the high-frequency shaft voltage, and by avoiding the conduction of the high-frequency shaft voltage to the half shaft through the speed reducer shaft system, the problem of EMC (Electro Magnetic Compatibility) caused by the antenna effect of the half shaft can be avoided.

[0090] The electric drive system according to this embodiment employs the bearing electric erosion suppression device in any one of Embodiments 1 to 4, further limits the hardware structure of the bearing electric erosion suppression device, not only has all the beneficial effects of the above embodiments, but also further guarantees the stable installation of the bearing electric erosion suppression device in the electric drive system by installing the PCB board and the support, can meet the needs of more application scenarios, and furthermore, by adding insulation treatment, the high-frequency shaft voltage can be further suppressed, and the electromagnetic interference caused by high-frequency radio waves can be reduced.

[0091] Embodiment Six Based on the concept of the same invention, referring to FIGS. 10 and 11 and based on Example Five, a sixth embodiment of the electric drive system of the present application is proposed. In this electric drive system, it includes a motor controller electrically connected to the motor, and a bearing electric erosion suppression device is mounted within this motor controller.

[0092] Furthermore, in this electric drive system, the input end of the bearing electric erosion suppression device may be electrically directly connected to the rotating shaft 30 via a conductive bypass part 70. Here, the conductive bypass part 70 may be any one of a conductive carbon brush, a conductive ring, a conductive elastic piece, a conductive brush, etc.

[0093] Furthermore, the output end of the bearing electric erosion suppression device is electrically connected to the motor case in the electric drive system, and the motor case is grounded, or, the output end of the bearing electric erosion suppression device is electrically connected to the motor controller case in the electric drive system, and the motor controller case is grounded.

[0094] In one embodiment, as shown in FIG. 10, it is a schematic diagram of the position of the bearing electric erosion suppression device in the electric drive system of this embodiment. This bearing electric erosion suppression device is mounted within the motor controller, and a capacitor module and a first resistance module as in Example One are adopted, that is, a capacitor C d and a resistance R d are included, and its PCB board 60 is provided within the motor controller. As shown in FIG. 10, the input end of the bearing electric erosion suppression device is connected to the rotating shaft 30 of the motor, and the output end is electrically connected to the motor controller case, and the motor controller case is grounded, that is, grounding is realized via the motor controller case.

[0095] In another embodiment, as shown in FIG. 11, it is a schematic diagram of another position of the bearing electrolytic corrosion suppression device in the electric drive system of this embodiment. This bearing electrolytic corrosion suppression device is mounted in the motor controller and adopts a capacitor module, a first resistance module and a reactance module as in the second embodiment, that is, a capacitor C d and a resistor R d and a ferrite bead FB d are included, and its PCB board 60 is provided in the motor controller. As shown in FIG. 11, the input end of the bearing electrolytic corrosion suppression device is connected to the rotating shaft 30 of the motor, and the output end is electrically connected to the motor controller case. The motor controller case is grounded, that is, grounding is realized through the motor controller case.

[0096] It is understood that the bearing electrolytic corrosion suppression device mounted in the motor controller in this embodiment may be the bearing electrolytic corrosion suppression device in any one of the above-mentioned first to fourth embodiments, and will not be described further here.

[0097] In the electric drive system according to this embodiment, the bearing electrolytic corrosion suppression device is directly mounted in the motor controller. In such a mounting method, since the motor controller is an essential device for realizing the control of the motor in the electric drive system, installing the bearing electrolytic corrosion suppression device therein is applicable to relatively many scenarios, meets the actual needs, and can expand the application range of this electric drive system, especially the bearing electrolytic corrosion suppression device therein.

[0098] Embodiment Seven Based on the same inventive concept, referring to FIGS. 12 and 13 and based on Embodiment Five, a seventh embodiment of the electric drive system of the present application is proposed. In this electric drive system, it includes a speed reducer electrically connected to the motor, and a bearing electrolytic corrosion suppression device is mounted in this speed reducer. This speed reducer includes a speed reducer shaft, and the speed reducer shaft is connected to the rotating shaft 30 of the motor.

[0099] Furthermore, in this electric drive system, the input end of the bearing electrolytic corrosion suppression device may be electrically connected to the reduction gear shaft in the electric drive system via a conductive bypass part 70, and the reduction gear shaft is connected to the rotating shaft 30. Here, the conductive bypass part 70 may be any one of a conductive carbon brush, a conductive ring, a conductive elastic piece, a conductive brush, etc.

[0100] The reduction gear shaft and the rotating shaft 30 of the motor are connected via a connecting member, and since the reduction gear shaft, the rotating shaft 30 of the motor, and the connecting member are made of a conductive material, when the bearing electrolytic corrosion suppression device is electrically connected to the reduction gear shaft, it will be indirectly electrically connected to the rotating shaft 30.

[0101] Furthermore, the output end of the bearing electrolytic corrosion suppression device is electrically connected to the motor case in the electric drive system, and the motor case is grounded, or The output end of the bearing electrolytic corrosion suppression device is electrically connected to the reduction gear case of the reduction gear in the electric drive system, and the reduction gear case is grounded.

[0102] In one embodiment, as shown in FIG. 12, it is a schematic diagram of the position of the bearing electrolytic corrosion suppression device in the electric drive system of this embodiment. This bearing electrolytic corrosion suppression device is provided on the reduction gear side in the electric drive system, and a capacitor module and a first resistance module as in Embodiment 1 are adopted, that is, a capacitor C d and a resistor R d are included, and its PCB board 60 is provided in the motor controller. As shown in FIG. 12, the input end of the bearing electrolytic corrosion suppression device is electrically connected to the reduction gear shaft, the reduction gear shaft is connected to the rotating shaft 30 of the motor, the output end of the bearing electrolytic corrosion suppression device is electrically connected to the reduction gear case, and the reduction gear case is grounded, that is, grounding is realized via the reduction gear case.

[0103] In another embodiment, as shown in FIG. 13, it is a schematic diagram of another position of the bearing electric erosion suppression device in the electric drive system of this embodiment. This bearing electric erosion suppression device is provided on the speed reducer side in the electric drive system, and adopts a capacitor module, a first resistance module and a reactance module as in the second embodiment, that is, a capacitor C connected in series d , a resistor R d and a ferrite bead FB d and its PCB board 60 is provided in the motor controller. As shown in FIG. 13, the input end of the bearing electric erosion suppression device is electrically connected to the speed reducer shaft, the speed reducer shaft is connected to the rotating shaft 30 of the motor, the output end of the bearing electric erosion suppression device is electrically connected to the speed reducer case, and the speed reducer case is grounded, that is, grounding is realized through the speed reducer case.

[0104] It is understood that the bearing electric erosion suppression device mounted on the speed reducer side in this embodiment may be the bearing electric erosion suppression device in any one of the above-mentioned first to fourth embodiments, and will not be described further here.

[0105] In the electric drive system according to this embodiment, a bearing electric erosion suppression device is mounted on the speed reducer side in the electric drive system. Such a mounting method can further reduce the influence of bearing electric erosion on the speed reducer side caused by high-frequency loop current.

[0106] Embodiment Eight Based on the same inventive concept, an embodiment of the electric vehicle of the present application is proposed. This electric vehicle may include a battery and an electric drive system, wherein the battery is used to provide electrical energy to the electric drive system, and the specific structure of the electric drive system may refer to any one of the above-mentioned first to seventh embodiments.

[0107] Specifically, the electric vehicle may be an electric-driven vehicle such as an electric car, an electric bicycle, or an electric tricycle. The above battery can be regarded as a power system. For example, it may include a power supply device and a power management electric circuit. After the power management electric circuit performs processes such as conversion and filtering on the voltage output by the power supply device, it is provided to the electric drive system, specifically to the motor of the electric drive system, and the motor can be operated to realize the electric drive function. It is understandable that the functions that can be realized by the internal devices of the above power system and the power management electric circuit can all be provided according to actual needs, and are not limited in this embodiment.

[0108] In the above process, in order to avoid EDM discharge, a bearing electric erosion suppression device is installed in parallel on the bearing of the motor, the rotating shaft of the motor is grounded through this bearing electric erosion suppression device, and by suppressing the high-frequency loop current generated in the bearing through the bearing electric erosion suppression device, the effect of suppressing bearing electric erosion is achieved, and the service life of the bearing is extended.

[0109] It should be noted that since the electric vehicle of this embodiment adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, and will not be described in detail here.

[0110] It should be noted that the numbers of the above embodiments of this application are only for description and do not represent the superiority or inferiority of the embodiments. The above embodiments are only optional embodiments of this application and do not limit the patent scope of this application. Under the concept of this application, equivalent structures or equivalent follow-up conversions made using the content of the specification and drawings of this application, or direct / indirect applications in other related technical fields are all included within the patent protection scope of this application.

Description of Reference Signs

[0111] 10 Electronic Component Module 20 End Cover 30 Rotating Shaft 40 Bearing 50 Insulating member 60 PCB substrate 61 Electrical connection fixing hole 70 Conductive bypass part 80 Position sensor 90 Support tool

Claims

1. An electric drive system, comprising: a motor including a motor case, a bearing and a rotating shaft provided in the motor case; a bearing electrolysis suppression device including a capacitor module connected in series and a first resistor module; wherein an input end of the bearing electrolysis suppression device is electrically connected to the rotating shaft, and an output end of the bearing electrolysis suppression device is grounded; the electric drive system.

2. The bearing electrolysis suppression device further includes a reactance module, an input end of which is connected to the first resistor module and an output end of which is grounded. The electric drive system according to claim 1.

3. The bearing electrolysis suppression device further includes a second resistor module, wherein the second resistor module is connected in parallel with the capacitor module and the first resistor module connected in series, or is connected in parallel with the capacitor module, the first resistor module and the reactance module connected in series. The electric drive system according to claim 2.

4. The capacitor module includes a plurality of capacitors connected electrically, the first resistor module includes a plurality of resistors connected electrically, the reactance module includes a plurality of ferrite beads connected electrically and / or a plurality of inductances connected electrically, and the second resistor module includes a plurality of resistors connected electrically. The electric drive system according to claim 3.

5. The electric drive system further includes: a motor controller and a speed reducer electrically connected to the motor; wherein the bearing electrolysis suppression device is provided on the motor, the motor controller or the speed reducer. The electric drive system according to claim 1 or 2.

6. The electric drive system further includes: an insulating member; wherein the bearing is provided in the motor case, the bearing is fitted outside the rotating shaft, and the insulating member is provided between the bearing and an end cover of the motor. The electric drive system according to claim 1 or 2.

7. The input end of the bearing electrolysis suppression device is electrically connected to the rotating shaft through a conductive bypass part. The electric drive system according to claim 1 or 2.

8. The electric drive system further includes: a speed reducer electrically connected to the motor, the speed reducer including a speed reducer shaft connected to the rotating shaft. The input end of the bearing electrolytic corrosion suppression device is electrically connected to the reduction gear shaft via a conductive bypass part. The electric drive system according to claim 1 or 2.

9. The electric drive system further includes a motor controller electrically connected to the motor, the output end of the bearing electrolytic corrosion suppression device is electrically connected to the motor case, and the motor case is grounded, or the output end of the bearing electrolytic corrosion suppression device is electrically connected to the case of the motor controller, and the case of the motor controller is grounded. The electric drive system according to claim 1 or 2.

10. An electric vehicle, a battery, and including the electric drive system according to any one of claims 1 to 9, wherein the battery is used to provide electrical energy to the electric drive system. An electric vehicle.

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