Equivalent voltage circuit of double-motor electric drive assembly

Abstract

The utility model provides an equivalent voltage circuit of a double-motor electric drive assembly. The equivalent voltage circuit comprises a first branch circuit and a second branch circuit, the first end of the first branch is connected with the first end of the second branch through a first reactor; the reactance value of the first reactance is determined by the reactance value of a power coupling device between a first motor and a second motor of the double-motor electric drive assembly; the voltage at the two ends of the first branch is determined by the common-mode voltage of the first motor; the voltage at the two ends of the second branch is determined by the common-mode voltage of the second motor; the first branch comprises a plurality of first sub-capacitors, and the capacitance value of each first capacitor is determined by the capacitance value of the first bearing; the second branch comprises a plurality of second sub-capacitors, and the capacitance value of each second capacitor is determined by the capacitance value of the second bearing; the first motor is connected with the wheels through a plurality of first bearings; the second motor is connected with the wheels through a plurality of second bearings. According to the equivalent voltage circuit of the double-motor electric drive assembly, the technical problem that the double-motor electric drive assembly is not provided with an equivalent voltage circuit can be solved.

Description

Technical Field

[0001] This application relates to the technical field of dual-motor electric drive, and more particularly, to an equivalent voltage circuit of a dual-motor electric drive assembly. Background Art

[0002] A bearing is a component in a motor. From a mechanical perspective, the bearing plays a role in supporting the rotor and transmitting power. Since the bearing is in an electrical environment (the motor), from the perspective of circuit analysis, the bearing can be regarded as a component with electrical characteristics.

[0003] The phenomenon of electric corrosion of motor bearings has been discovered in the motor industry for a long time, and there has been continuous tracking and research in the industry. Bearing voltage is a very crucial technical indicator for studying electric corrosion of motor bearings. Currently, the motor bearing voltage calculation model adopted in the industry is a single-motor bearing voltage calculation model.

[0004] Under the background that dual-motor electric drive assemblies are gradually becoming the focus of development, there is an urgent need for an equivalent voltage circuit of a dual-motor electric drive assembly. Summary of the Utility Model

[0005] The purpose of the embodiments of this application is to provide an equivalent voltage circuit of a dual-motor electric drive assembly.

[0006] The equivalent voltage circuit of the dual-motor assembly provided by the embodiments of this application includes:

[0007] A first branch and a second branch;

[0008] The first end of the first branch and the first end of the second branch are connected through a first reactance;

[0009] The reactance value of the first reactance is determined by the reactance value of the power coupling device between the first motor and the second motor of the dual-motor electric drive assembly;

[0010] The voltage across the first branch is determined by the common-mode voltage of the first motor;

[0011] The voltage across the second branch is determined by the common-mode voltage of the second motor;

[0012] The first branch includes: a plurality of first sub-capacitors, and the capacitance value of each first sub-capacitor is determined by the capacitance value of the first bearing;

[0013] The second branch includes: a plurality of second sub-capacitors, and the capacitance value of each second sub-capacitor is determined by the capacitance value of the second bearing;

[0014] The first motor is connected to the wheel through a plurality of the first bearings;

[0015] The second motor is connected to the wheel through a plurality of the second bearings.

[0016] In the above implementation process, an equivalent voltage circuit of the dual-motor assembly is provided. This equivalent voltage circuit comprehensively considers the power coupling device and bearings of the dual-motor electric drive assembly, as well as the operating voltages of the two motors. Based on this equivalent voltage circuit, the voltages borne by each bearing of the dual-motor electric drive assembly during operation can be calculated.

[0017] Further, the first branch includes: a first capacitor; a second capacitor and a first sub-branch;

[0018] The first capacitor is connected in parallel with the branch formed by the series connection of the second capacitor and the first sub-branch;

[0019] The series connection point of the second sub-capacitor and the first sub-branch is connected to the first reactance;

[0020] The first sub-branch includes a plurality of the first sub-capacitors;

[0021] The capacitance value of the first capacitor is determined by the capacitance value between the stator winding of the first motor and the housing of the dual-motor electric drive assembly;

[0022] The capacitance value of the second capacitor is determined by the capacitance value between the stator winding of the first motor and the rotor of the first motor.

[0023] In the above implementation process, a specific connection structure of the first branch is provided. This connection structure comprehensively considers the stator winding and rotor of the first motor. Based on this equivalent voltage circuit, the voltages borne by each bearing of the dual-motor electric drive assembly during operation can be calculated.

[0024] Further, the second branch includes: a third capacitor; a fourth capacitor and a second sub-branch;

[0025] The third capacitor is connected in parallel with the branch formed by the series connection of the fourth capacitor and the second sub-branch;

[0026] The series connection point of the fourth capacitor and the second sub-branch is connected to the first reactance;

[0027] The second sub-branch includes a plurality of the second sub-capacitors;

[0028] The capacitance value of the third capacitor is determined by the capacitance value between the stator winding of the first motor and the housing of the dual-motor electric drive assembly;

[0029] The capacitance value of the fourth capacitor is determined by the capacitance value between the stator winding of the second motor and the rotor of the second motor.

[0030] In the above implementation process, the specific connection structure of the second branch is provided. This connection structure comprehensively considers the stator winding of the second motor and the rotor of the second motor. Based on this equivalent voltage circuit, the voltages borne by each bearing of the dual-motor electric drive assembly during operation can be calculated.

[0031] Further, the first branch further includes: a first equivalent reactance;

[0032] The first motor is connected to the wheel through a first multi-stage transmission assembly;

[0033] Multiple said first bearings belong to first sub-transmission assemblies of different levels of the first multi-stage transmission assembly;

[0034] The first capacitors corresponding to the first bearings of the first sub-transmission assemblies of the same level are connected in parallel;

[0035] After the first capacitors corresponding to the first sub-transmission assemblies of the same level are connected in parallel, they are connected in series with one said first equivalent reactance;

[0036] The reactance value of the first equivalent reactance corresponding between the first sub-transmission assemblies of different levels is determined by the reactance value between the transmission shafts of the first sub-transmission assemblies of different levels.

[0037] In the above implementation process, the first equivalent reactance corresponding between the first sub-transmission assemblies of different levels is considered. The first equivalent reactance corresponding between the first sub-transmission assemblies of the same level is determined by the reactance value between the transmission shafts of the first sub-transmission assemblies of different levels, so that the equivalent voltage circuit of the dual-motor electric drive assembly of the present application can reflect the voltage of the bearing.

[0038] Further, the second branch further includes: a second equivalent reactance;

[0039] The second motor is connected to the wheel through a second multi-stage transmission assembly;

[0040] Multiple said second bearings belong to second sub-transmission assemblies of different levels of the second multi-stage transmission assembly;

[0041] The second capacitors corresponding to the second bearings of the second sub-transmission assemblies of the same level are connected in parallel;

[0042] After the second capacitors corresponding to the second sub-transmission assemblies of the same level are connected in parallel, they are connected in series with one said second equivalent reactance;

[0043] The reactance value of the second equivalent reactance corresponding between the second sub-transmission assemblies of different levels is determined by the reactance value between the transmission shafts of the second sub-transmission assemblies of different levels.

[0044] In the above implementation process, the second equivalent reactances corresponding to the second sub-drive components at different levels are considered. The second equivalent reactance corresponding to the second sub-drive components at the same level is determined by the reactance between the drive shafts of the second sub-drive components at different levels and the drive shafts of the second sub-drive components at the upper second level connected thereto, so that the equivalent voltage circuit of the dual-motor electric drive assembly of the present application can more accurately reflect the voltage of the bearing.

[0045] Further, the capacitance value of the first capacitor is 2 to 5 times the capacitance value between the stator winding of the first motor and the housing of the dual-motor electric drive assembly.

[0046] Further, the capacitance value of the third capacitor is 2 to 5 times the capacitance value between the stator winding of the second motor and the housing of the dual-motor electric drive assembly.

[0047] Further, the branches formed by connecting the first sub-capacitors and the first equivalent reactances corresponding to each first sub-drive component are connected in parallel with the first sub-capacitors corresponding to the first sub-drive components at the upper level of each first sub-drive component.

[0048] In the above implementation process, the connection manner of the first sub-capacitors and the first equivalent reactances corresponding to each first sub-drive component and the first sub-capacitors of the first sub-drive components at the upper level of each first sub-drive component is provided, so that the equivalent voltage circuit of the dual-motor electric drive assembly of the present application can more accurately reflect the voltage of the bearing.

[0049] Further, the branches formed by connecting the second sub-capacitors and the second equivalent reactances corresponding to each second sub-drive component are connected in parallel with the second sub-capacitors of the second sub-drive components at the upper level of each second sub-drive component.

[0050] In the above implementation process, the connection manner of the second sub-capacitors, the second equivalent reactances corresponding to each second sub-drive component and the second sub-capacitors of the second sub-drive components at the upper level of each second sub-drive component is provided, so that the equivalent voltage circuit of the dual-motor electric drive assembly of the present application can more accurately reflect the voltage of the bearing.

[0051] Further, when the second motor is operating, the voltage across the second branch is the common-mode voltage of the second motor;

[0052] When the first motor is operating, the voltage across the first branch is the common-mode voltage of the first motor.

[0053] In the above implementation process, when different motors of the vehicle are in the operating state, the voltages of the first branch and the second branch change. Based on this, the equivalent voltage circuit can be analyzed more accurately according to the operating state of the electric drive, and the voltage of the bearing in the dual-motor electric drive during operation can be obtained.

[0054] Other features and advantages disclosed in this application will be set forth in the following description, or, some features and advantages can be inferred from the description or be undoubtedly determined, or can be learned by implementing the above technologies disclosed in this application.

[0055] To make the above objects, features, and advantages of this application more obvious and understandable, the following specific preferred embodiments are given, in conjunction with the accompanying drawings, and the detailed description is as follows. Description of the Drawings

[0056] To more clearly illustrate the technical solutions in the embodiments of this application, the following briefly introduces the drawings required to be used in the embodiments of this application. It should be understood that the following drawings only show some embodiments of this application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0057] Figure 1 It is the equivalent voltage circuit of the dual-motor electric drive assembly provided for the embodiments of this application. Detailed Embodiments

[0058] The following will describe the technical solutions in the embodiments of this application in conjunction with the drawings in the embodiments of this application.

[0059] It should be noted that: similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0060] See Figure 1 , this application provides an equivalent voltage circuit of a dual-motor electric drive assembly, including:

[0061] The first branch 1 and the second branch 2;

[0062] The first end of the first branch 1 and the first end of the second branch 2 are connected through a first reactance Z0;

[0063] The reactance value of the first reactance Z0 is determined by the reactance value of the power coupling device between the first motor and the second motor of the dual-motor electric drive assembly;

[0064] In some embodiments, the reactance value of the first reactance Z0 is equal to the reactance value of the power coupling device between the first motor and the second motor of the dual-motor electric drive assembly.

[0065] The voltage across the first branch 1 is determined by the common-mode voltage of the first motor;

[0066] The voltage across the two ends of the second branch 2 is determined by the common-mode voltage of the second motor;

[0067] The first branch 1 includes: a plurality of first sub-capacitors, and the capacitance value of each first sub-capacitor is determined by the capacitance value of the first bearing;

[0068] The second branch 2 includes: a plurality of second sub-capacitors, and the capacitance value of each second sub-capacitor is determined by the capacitance value of the second bearing;

[0069] The first motor is connected to the wheel through a plurality of the first bearings;

[0070] The second motor is connected to the wheel through a plurality of the second bearings.

[0071] In the embodiment of the present application, the dual-motor electric drive assembly at least includes: a first motor and a second motor; wherein, the first motor and the second motor are connected through a power coupling device, and the coupled electric torque is amplified by a transmission system and transmitted to the wheel through a differential device.

[0072] Wherein, the power coupling device, the transmission system and the differential system at least include a transmission component formed by a plurality of transmission shafts and a plurality of bearings; wherein, the multi-stage transmission component includes: a plurality of sub-transmission components; the first motor is connected to the wheel through a first multi-stage transmission component corresponding to the first motor; the second motor is connected to the wheel through a second multi-stage transmission component corresponding to the second motor; the first multi-stage transmission component includes: a plurality of first sub-transmission components; the second multi-stage transmission component includes: a plurality of second sub-transmission components; a plurality of first multi-stage transmission components are connected in sequence; a plurality of second multi-stage transmission components are connected in sequence; the present application does not make specific limitations on the connection method; a plurality of first sub-transmission components can be respectively located in the power coupling device, the transmission system and the differential system; a plurality of second sub-transmission components can be respectively located in the power coupling device, the transmission system and the differential system.

[0073] In the present application, a plurality of first sub-transmission components are connected to each other to form a multi-layer first sub-transmission component (the first sub-transmission component of the first level, the first sub-transmission component of the second level......, and so on), and the first sub-transmission component of the lower level is closer to the first motor than the first sub-transmission component of the higher level, and the first sub-transmission component of the higher level is closer to the wheel than the first sub-transmission component of the lower level.

[0074] The upper-layer sub-transmission component of the first sub-transmission component of the first level is the first sub-transmission component of the second level, and the upper-layer sub-transmission component of the first sub-transmission component of the second level is the first sub-transmission component of the third level......, and so on.

[0075] A plurality of second sub - transmission components are interconnected to form multiple layers of second sub - transmission components (the second sub - transmission components of the first level, the second sub - transmission components of the second level..., and so on). The second sub - transmission components of the lower level are closer to the second motor than those of the higher level, and the second sub - transmission components of the higher level are closer to the wheel than those of the lower level.

[0076] The upper - level sub - transmission component of the second sub - transmission component of the first level is the second sub - transmission component of the second level, and the upper - level sub - transmission component of the second sub - transmission component of the second level is the second sub - transmission component of the third level..., and so on.

[0077] There can be multiple first bearings. Each first sub - transmission component includes at least: a first bearing; each first sub - transmission component further includes: a transmission shaft; in some embodiments, the first sub - transmission component includes: two first bearings and a transmission shaft; the two first bearings of each first sub - transmission component are installed at both ends of the transmission shaft of each first sub - transmission component.

[0078] The transmission shafts of the first sub - transmission components of different levels are connected in sequence to form a first multi - stage transmission component.

[0079] There can be multiple second bearings. Each second sub - transmission component includes at least: a second bearing; each second sub - transmission component further includes: a transmission shaft; in some embodiments, the second sub - transmission component includes: two second bearings and a transmission shaft; the two second bearings of each second sub - transmission component are installed at both ends of the transmission shaft of each second sub - transmission component.

[0080] The transmission shafts of the second sub - transmission components of different levels are connected in sequence to form a second multi - stage transmission component.

[0081] Exemplarily, referring to Figure 1 , the first sub - capacitor includes: capacitor CB1, capacitor CB2, capacitor CB3, capacitor CB5, capacitor CB6, capacitor CB9, capacitor CB10; the second sub - capacitor includes: capacitor CB3, capacitor CB4, capacitor CB7, capacitor CB8, capacitor CB11, capacitor CB12.

[0082] In the embodiments of the present application, the equivalent capacitance and equivalent reactance of the bearings can be measured in advance through experiments.

[0083] In the above implementation process, an equivalent voltage circuit of the dual - motor assembly is provided. This equivalent voltage circuit comprehensively considers the power coupling device and bearings of the dual - motor electric drive assembly, as well as the working voltage of the dual - motor. Based on this equivalent voltage circuit, the voltage borne by each bearing when the dual - motor electric drive assembly is working can be calculated.

[0084] In some embodiments, the first branch 1 includes: a first capacitor; a second capacitor and a first sub-branch;

[0085] The first capacitor is in parallel with the branch formed by the series connection of the second capacitor and the first sub-branch;

[0086] The series connection point of the second sub-capacitor and the first sub-branch is connected to the first reactance Z0;

[0087] The first sub-branch includes a plurality of the first sub-capacitors;

[0088] The capacitance value of the first capacitor is determined by the capacitance value between the stator winding of the first motor and the housing of the dual-motor electric drive assembly;

[0089] The capacitance value of the second capacitor is determined by the capacitance value between the stator winding of the first motor and the rotor of the first motor.

[0090] Exemplarily, referring to Figure 1 , the first capacitor is 3Cwf1, the second capacitor is Cwr1, and the first sub-branch includes: capacitor Cb1, capacitor Cb2, capacitor Cb5, capacitor Cb6, capacitor Cb9, capacitor Cb10, reactance Z1 and reactance Z3.

[0091] In the above implementation process, the specific connection structure of the first branch 1 is provided. This connection structure comprehensively considers the stator winding of the first motor and the rotor of the first motor. Based on this equivalent voltage circuit, the voltages borne by each bearing of the dual-motor electric drive assembly during operation can be calculated.

[0092] In some embodiments, the second branch 2 includes: a third capacitor; a fourth capacitor and a second sub-branch;

[0093] The third capacitor is in parallel with the branch formed by the series connection of the fourth capacitor and the second sub-branch;

[0094] The series connection point of the fourth capacitor and the second sub-branch is connected to the first reactance Z0;

[0095] The second sub-branch includes a plurality of the second sub-capacitors;

[0096] The capacitance value of the third capacitor is determined by the capacitance value between the stator winding of the first motor and the housing of the dual-motor electric drive assembly;

[0097] The capacitance value of the fourth capacitor is determined by the capacitance value between the stator winding of the second motor and the rotor of the second motor.

[0098] Exemplarily, referring to Figure 1, the third capacitor is 3Cwf2, the fourth capacitor is Cwr2, and the second sub-branch includes: capacitor Cb11, capacitor Cb12, capacitor Cb7, capacitor Cb8, capacitor Cb3, capacitor Cb4, reactance Z2, and reactance Z4.

[0099] In the above implementation process, the specific connection structure of the second branch 2 is provided. This connection structure comprehensively considers the stator winding of the second motor and the rotor of the second motor. Based on this equivalent voltage circuit, the voltage borne by each bearing of the dual-motor electric drive assembly during operation can be calculated.

[0100] In some embodiments, the first branch 1 further includes: a first equivalent reactance;

[0101] The first motor is connected to the wheel through a first multi-stage transmission assembly;

[0102] Multiple said first bearings belong to the first sub-transmission assemblies of different levels of the first multi-stage transmission assembly;

[0103] The first capacitors corresponding to the first sub-transmission assemblies of the same level are connected in parallel;

[0104] That is to say, if there are two bearings in a certain level of the first sub-transmission assembly, then there are two first capacitors corresponding to the first sub-transmission assembly of this level, each equivalent to one bearing. Exemplarily, see Figure 1 , the first sub-transmission assembly of the first level includes two bearings: then there are two capacitors corresponding to the first sub-transmission assembly of the first level, which are capacitor Cb9 and Cb10 respectively; Cb9 and Cb10 respectively correspond to different bearings of the first sub-transmission assembly of the first level. The first sub-transmission assembly of the second level includes two bearings: then there are two capacitors corresponding to the first sub-transmission assembly of the first level, which are capacitor Cb5 and capacitor Cb6 respectively; capacitor Cb5 and capacitor Cb6 respectively correspond to different bearings of the first sub-transmission assembly of the second level. The first sub-transmission assembly of the third level includes two bearings: then there are two capacitors corresponding to the third level, which are capacitor Cb1 and capacitor Cb2 respectively; capacitor Cb1 and capacitor Cb2 respectively correspond to different bearings of the first sub-transmission assembly of the third level.

[0105] The first capacitors corresponding to the first sub-transmission assemblies of the same level are connected in parallel and then connected in series with a said first equivalent reactance;

[0106] The reactance values of the first equivalent reactances corresponding to different levels of the first sub-transmission assemblies are determined by the reactance values between the drive shafts of different levels of the first sub-transmission assemblies.

[0107] In some embodiments, the branches formed by connecting the first sub-capacitors and the first equivalent reactances corresponding to each first sub-transmission component are connected in parallel with the first sub-capacitors corresponding to the first sub-transmission components at the upper level of each first sub-transmission component.

[0108] The first equivalent reactance corresponding to each first sub-transmission component here refers to the drive shaft of the first sub-transmission component at this level and the first equivalent reactance corresponding to the drive shaft of the first sub-transmission component at the upper level of this level; the first equivalent reactance corresponding to the first sub-transmission component at the first level refers to the first equivalent reactance formed by the drive shaft of the first sub-transmission component at the first level and the drive shaft of the first sub-transmission component at the second level; the first equivalent reactance corresponding to the first sub-transmission component at the second level refers to the first equivalent reactance formed by the drive shaft of the first sub-transmission component at the second level and the drive shaft of the first sub-transmission component at the third level.

[0109] In some embodiments, the reactance values of the first equivalent reactances corresponding to the first sub-transmission components at different levels are the same as the reactance values of the drive shafts between the first sub-transmission components at different levels.

[0110] Exemplarily, the first equivalent reactance includes: reactance Z1 and reactance Z3. Capacitors Cb9 and Cb10 belong to the first sub-transmission components at the first level; capacitors Cb5 and Cb6 belong to the first sub-transmission components at the second level; capacitors Cb1 and Cb2 belong to the first sub-transmission components at the third level; the reactance value of reactance Z3 is determined by the reactance between the drive shafts of the first sub-transmission components at the first level and the second level; the reactance value of reactance Z1 is determined by the reactance value between the drive shafts of the first sub-transmission components at the second level and the third level;

[0111] In some embodiments, reactance Z1 is equal to the equivalent reactance between the drive shafts of the first sub-transmission components at the second level and the third level.

[0112] In some embodiments, reactance Z3 is equal to the equivalent reactance between the drive shafts of the first sub-transmission components at the first level and the second level.

[0113] The branches formed by connecting capacitors Cb9 and Cb10 in parallel and then in series with reactance Z3 are connected in parallel with the branches formed by connecting capacitors Cb5 and Cb6 in parallel. The branches formed by capacitors Cb9, Cb10, reactance Z3, capacitors Cb5 and Cb6 are connected in series with reactance Z1. The branches formed by capacitors Cb9, Cb10, reactance Z3, capacitors Cb5 and Cb6, and reactance Z1 are connected in parallel with capacitors Cb1 and Cb2.

[0114] In the above implementation process, the first equivalent reactance corresponding to the first sub-drive components at different levels is considered. The first equivalent reactance between the first sub-drive components at the same level is determined by the reactance value between the drive shafts of the first sub-drive components at different levels, so that the equivalent voltage circuit of the dual-motor electric drive assembly of the present application can reflect the voltage of the bearing.

[0115] In the above implementation process, the connection manner of the first sub-capacitance and the first equivalent reactance corresponding to each first sub-drive component and the first sub-capacitance of the first sub-drive component at the upper level of each first sub-drive component is provided, so that the equivalent voltage circuit of the dual-motor electric drive assembly of the present application can more accurately reflect the voltage of the bearing.

[0116] In some embodiments, the second branch 2 further includes: a second equivalent reactance;

[0117] The second motor is connected to the wheel through a second multi-stage drive assembly;

[0118] The plurality of second bearings belong to the second sub-drive components at different levels of the second multi-stage drive assembly;

[0119] The second sub-capacitances corresponding to the second bearings of the second sub-drive components belonging to the same level are connected in parallel;

[0120] That is to say, if there are two bearings in the second sub-drive component at a certain level, then there are two second sub-capacitances corresponding to the second sub-drive component at that level, each equivalently corresponding to one bearing. Exemplarily, see Figure 1 , the second sub-drive component at the first level includes two bearings: then there are two capacitances corresponding to the second sub-drive component at the first level, which are capacitance Cb11 and Cb12 respectively; capacitance Cb11 and Cb12 respectively correspond to different bearings of the second sub-drive component at the first level. The second sub-drive component at the second level includes two bearings: then there are two capacitances corresponding to the second sub-drive component at the first level, which are capacitance Cb7 and capacitance Cb8 respectively; capacitance Cb7 and Cb8 respectively correspond to different bearings of the second sub-drive component at the second level. The second sub-drive component at the third level includes two bearings: then there are two capacitances corresponding to the third level, which are capacitance Cb3 and capacitance Cb4 respectively; capacitance Cb3 and Cb4 respectively correspond to different bearings of the second sub-drive component at the third level.

[0121] The second capacitances corresponding to the second sub-drive components at the same level are connected in parallel and then connected in series with one of the second equivalent reactances;

[0122] The reactance value of the second equivalent reactance between the second sub-drive components at different levels is determined by the reactance value between the drive shafts of the second sub-drive components at different levels.

[0123] In some embodiments, the reactance values of the second equivalent reactances corresponding between the second sub-transmission components of different levels are the same as the reactance values of the transmission shafts between the second sub-transmission components of different levels.

[0124] In some embodiments, the branches formed by connecting the second sub-capacitors and the second equivalent reactances corresponding to each second sub-transmission component are connected in parallel with the second sub-capacitors of the second sub-transmission components at the upper level of each second sub-transmission component.

[0125] The second equivalent reactance corresponding to each second sub-transmission component here refers to the transmission shaft of the second sub-transmission component at this level and the second equivalent reactance corresponding to the transmission shaft of the second sub-transmission component at the upper level of this level; the second equivalent reactance corresponding to the second sub-transmission component at the first level refers to the second equivalent reactance formed by the transmission shaft of the second sub-transmission component at the first level and the transmission shaft of the second sub-transmission component at the second level; the second equivalent reactance corresponding to the second sub-transmission component at the second level refers to the second equivalent reactance formed by the transmission shaft of the second sub-transmission component at the second level and the transmission shaft of the second sub-transmission component at the third level.

[0126] Exemplarily, the second equivalent reactance includes: reactance Z2 and reactance Z4. Capacitors Cb11 and Cb12 belong to the second sub-transmission components at the first level; capacitors Cb7 and Cb8 belong to the second sub-transmission components at the second level; capacitors Cb3 and Cb4 belong to the second sub-transmission components at the third level; the reactance value of reactance Z4 is determined by the reactance between the transmission shaft of the second sub-transmission component at the first level and the transmission shaft of the second sub-transmission component at the second level; the reactance value of reactance Z2 is determined by the reactance value between the transmission shaft of the second sub-transmission component at the second level and the transmission shaft of the second sub-transmission component at the third level;

[0127] In some embodiments, the reactance Z4 is equal to the equivalent reactance between the transmission shaft of the first sub-transmission component at the second level and the transmission shaft of the first sub-transmission component at the third level.

[0128] In some embodiments, the reactance Z2 is equal to the equivalent reactance between the transmission shaft of the second sub-transmission component at the first level and the transmission shaft of the second sub-transmission component at the second level.

[0129] The branches formed by capacitors Cb11 and Cb12 in parallel and then in series with reactance Z4 are connected in parallel with the branches formed by capacitors Cb7 and Cb8. The branches formed by capacitors Cb11, Cb12, reactance Z4, capacitors Cb7 and Cb8 are connected in series with reactance Z2. The branches formed by capacitors Cb1, Cb12, reactance Z4, capacitors Cb7 and Cb8, reactance Z1 are connected in parallel with capacitors Cb3 and Cb4.

[0130] In some embodiments, a first capacitor is equivalent to a bearing, and a second capacitor is equivalent to a bearing.

[0131] In this application, the capacitance values of capacitor CB1, capacitor CB2, capacitor CB3, capacitor CB5, capacitor CB6, capacitor CB9, capacitor CB10, capacitor CB3, capacitor CB4, capacitor CB7, capacitor CB8, capacitor CB11, and capacitor CB12 are the same as the equivalent capacitance values of their equivalent bearings.

[0132] Exemplarily, the first sub-transmission assembly of the first level includes two bearings. The capacitance value of one of the two bearings of the first sub-transmission assembly of the first level is the same as the capacitance value of capacitor C9, and the capacitance value of the other of the two bearings of the first sub-transmission assembly of the first level is the same as the capacitance value of capacitor C10. The same applies to other first capacitors or second capacitors, which will not be elaborated here.

[0133] In the above implementation process, the second equivalent reactance corresponding to the second sub-transmission assemblies of different levels is considered. The second equivalent reactance corresponding to the second sub-transmission assemblies of the same level is determined by the reactance between the transmission shafts of the second sub-transmission assemblies of different levels and the transmission shafts of the second sub-transmission assemblies of the upper two levels connected thereto, so that the equivalent voltage circuit of the dual-motor electric drive assembly of this application can more accurately reflect the voltage of the bearings.

[0134] In the above implementation process, the connection manner of the second sub-capacitor, the second equivalent reactance corresponding to each second sub-transmission assembly, and the second sub-capacitor of the second sub-transmission assembly of the upper level of each second sub-transmission assembly is provided, so that the equivalent voltage circuit of the dual-motor electric drive assembly of this application can more accurately reflect the voltage of the bearings.

[0135] In some embodiments, the capacitance value of the first capacitor is 2 to 5 times the capacitance value between the stator winding of the first motor and the housing of the dual-motor electric drive assembly.

[0136] In some embodiments, the capacitance value of the first capacitor is 3 times the capacitance value between the stator winding of the first motor and the housing of the dual-motor electric drive assembly.

[0137] Exemplarily, the capacitance value of capacitor 3Cwf1 is 3 times the capacitance value between the stator winding of the first motor and the housing of the dual-motor electric drive assembly.

[0138] In some embodiments, the capacitance value of the third capacitor is 2 to 5 times the capacitance value between the stator winding of the second motor and the housing of the dual-motor electric drive assembly.

[0139] In some embodiments, the capacitance value of the third capacitor is 3 times the capacitance value between the stator winding of the second motor and the housing of the dual-motor electric drive assembly.

[0140] Exemplarily, the capacitance value of the capacitor 3Cwf2 is three times the capacitance value between the stator winding of the second motor and the housing of the dual-motor electric drive assembly.

[0141] In some embodiments, the capacitance value of the second capacitor is equal to the capacitance value between the stator winding of the first motor and the rotor of the first motor.

[0142] In some embodiments, the capacitance value of the fourth capacitor is equal to the capacitance value between the stator winding of the second motor and the rotor of the second motor.

[0143] In some embodiments, when the second motor is operating, the voltage across the second branch 2 is the common-mode voltage of the second motor;

[0144] When the first motor is operating, the voltage across the first branch 1 is the common-mode voltage of the first motor.

[0145] Exemplarily, when the first motor is operating, the voltage across the first branch is the common-mode voltage V1 of the first motor.

[0146] Exemplarily, when the first motor is not operating, the voltage across the first branch is 0.

[0147] Exemplarily, when the second motor is operating, the voltage across the second branch is the common-mode voltage V2 of the second motor.

[0148] Exemplarily, when the second motor is not operating, the voltage across the second branch is 0.

[0149] In the above implementation process, when different motors of the vehicle are in the operating state, the voltages of the first branch 1 and the second branch 2 change. Based on this, the equivalent voltage circuit can be analyzed more accurately according to the operating state of the electric drive to obtain the voltage of the bearing in the dual-motor electric drive during operation.

[0150] The above are only embodiments of the present application and are not used to limit the protection scope of the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application. It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0151] The above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

[0152] It should be noted that, in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without more limitations, an element defined by the statement "including one..." does not exclude the existence of another identical element in the process, method, article or device including the element.

Claims

1. An equivalent voltage circuit of a dual-motor electric drive assembly, characterized in that, including: a first branch and a second branch; the first ends of the first branch and the second branch are connected through a first reactance; the reactance value of the first reactance is determined by the reactance value of a power coupling device between a first motor and a second motor of the dual-motor electric drive assembly; the voltage across the two ends of the first branch is determined by the common-mode voltage of the first motor; the voltage across the two ends of the second branch is determined by the common-mode voltage of the second motor; the first branch includes: a plurality of first sub-capacitors, and the capacitance value of each first sub-capacitor is determined by the capacitance value of a first bearing; the second branch includes: a plurality of second sub-capacitors, and the capacitance value of each second sub-capacitor is determined by the capacitance value of a second bearing; the first motor is connected to a wheel through a plurality of the first bearings; the second motor is connected to a wheel through a plurality of the second bearings.

2. The equivalent voltage circuit of the dual-motor electric drive assembly according to claim 1, characterized in that, the first branch includes: a first capacitor; a second capacitor and a first sub-branch; the first capacitor is connected in parallel with a branch formed by connecting the second capacitor in series with the first sub-branch; the series connection point of the second sub-capacitor and the first sub-branch is connected to the first reactance; the first sub-branch includes a plurality of the first sub-capacitors; the capacitance value of the first capacitor is determined by the capacitance value between the stator winding of the first motor and the housing of the dual-motor electric drive assembly; the capacitance value of the second capacitor is determined by the capacitance value between the stator winding of the first motor and the rotor of the first motor.

3. The equivalent voltage circuit of the dual-motor electric drive assembly according to claim 1, characterized in that, the second branch includes: a third capacitor; a fourth capacitor and a second sub-branch; the third capacitor is connected in parallel with a branch formed by connecting the fourth capacitor in series with the second sub-branch; the series connection point of the fourth capacitor and the second sub-branch is connected to the first reactance; the second sub-branch includes a plurality of the second sub-capacitors; the capacitance value of the third capacitor is determined by the capacitance value between the stator winding of the first motor and the housing of the dual-motor electric drive assembly; the capacitance value of the fourth capacitor is determined by the capacitance value between the stator winding of the second motor and the rotor of the second motor.

4. The equivalent voltage circuit of the dual-motor electric drive assembly according to claim 2, wherein, the first branch further includes: a first equivalent reactance; the first motor is connected to the wheel through a first multi-stage transmission assembly; a plurality of the first bearings belong to first sub-transmission assemblies of different levels of the first multi-stage transmission assembly; the first sub-capacitors corresponding to the first bearings of the first sub-transmission assemblies of the same level are connected in parallel; the first sub-capacitors corresponding to the first sub-transmission assemblies of the same level are connected in parallel and then connected in series with a first equivalent reactance; the reactance value of the first equivalent reactance corresponding to the first sub-transmission assemblies of different levels is determined by the reactance value between the transmission shafts of the first sub-transmission assemblies of different levels.

5. The equivalent voltage circuit of the dual-motor electric drive assembly according to claim 3, characterized in that, the second branch further includes: a second equivalent reactance; the second motor is connected to the wheel through a second multi-stage transmission assembly; a plurality of the second bearings belong to second sub-transmission assemblies of different levels of the second multi-stage transmission assembly; the second sub-capacitors corresponding to the second bearings of the second sub-transmission assemblies of the same level are connected in parallel; the second sub-capacitors corresponding to the second sub-transmission assemblies of the same level are connected in parallel and then connected in series with a second equivalent reactance; The reactance values of the second equivalent reactances corresponding to the second sub-drive components at different levels are determined by the reactance values between the drive shafts of the second sub-drive components at different levels.

6. The equivalent voltage circuit of the dual-motor electric drive assembly according to claim 2, characterized in that, The capacitance value of the first capacitor is 2 to 5 times the capacitance value between the stator winding of the first motor and the housing of the dual-motor electric drive assembly.

7. The equivalent voltage circuit of the dual-motor electric drive assembly according to claim 3, characterized in that, The capacitance value of the third capacitor is 2 to 5 times the capacitance value between the stator winding of the second motor and the housing of the dual-motor electric drive assembly.

8. The equivalent voltage circuit of the dual-motor electric drive assembly according to claim 4, wherein The branches formed by connecting the first sub-capacitors and the first equivalent reactances corresponding to each first sub-drive component are connected in parallel with the first sub-capacitors corresponding to the first sub-drive components at the upper level of each first sub-drive component.

9. The equivalent voltage circuit of the dual-motor electric drive assembly according to claim 5, characterized in that, The branches formed by connecting the second sub-capacitors and the second equivalent reactances corresponding to each second sub-drive component are connected in parallel with the second sub-capacitors corresponding to the second sub-drive components at the upper level of each second sub-drive component.

10. The equivalent voltage circuit of the dual-motor electric drive assembly according to any one of claims 1-8, characterized in that, When the second motor is operating, the voltage across the second branch is the common-mode voltage of the second motor; When the first motor is operating, the voltage across the first branch is the common-mode voltage of the first motor.

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