Dual-motor device and control method and system thereof, computer program and storage medium

Abstract

The invention discloses a dual-motor device and a control method and system thereof, a computer program and a storage medium, and relates to the technical field of motors, in particular to structures, control and driving modes of motors, in particular to design of the dual-motor device. The device comprises a large motor, a small motor and a rotating shaft, the small motor comprises a small motor stator and a small motor rotor, the large motor comprises a large motor stator and a large motor rotor, and according to the method, the expected rotating speed, the temperature of the small motor stator and the actual rotating speed are monitored in real time, the double-motor operation state is judged, and the power saving coefficient p of the small motor is calculated; a stator temperature estimation model based on rotating speed and temperature data is constructed, a temperature coefficient k during excess operation is deduced, finally, the operation feasibility of the small motor between power optimization and thermal safety is evaluated through a k-p relation, and dynamic coordination control of a dual-motor system is realized. The technical problem that low-speed and high-efficiency and high-speed and high-power requirements are difficult to meet by a traditional single motor is solved. The motor is suitable for the fields of electric automobiles, ship driving and the like.

Description

Technical Field

[0001] The present invention relates to the field of motor technology in engineering technology, specifically to the structure, control and driving mode of motors, especially the design of dual-motor devices. Background Art

[0002] With the continuous development of electrification and intelligent technologies, drive motors are increasingly widely used in multiple fields. Modern transportation means such as electric vehicles and ship drives have increasingly high performance requirements for motors, especially in terms of multi-functional adaptation under different working conditions, facing unprecedented challenges. The drive motor not only needs to maintain high efficiency, low vibration and low noise at low speeds to meet the long-term low-power operation requirements; at the same time, at high speeds, it also needs to have high-power output and be able to withstand short-term overheating pressure, which poses higher technical requirements for the design of the motor.

[0003] In practical applications, the motor needs to be able to operate stably within a wide speed range, which means that the power output range of the motor is also very wide. With the change of requirements, the working conditions of the motor may need to cover from low-power, low-speed operation modes to high-power, high-speed intense working modes. At low speeds, the motor not only needs to have high efficiency, but also reduce vibration and noise to avoid unnecessary energy loss; while at high speeds, the motor needs to be able to quickly and efficiently provide a large amount of power and be able to withstand a large thermal load in a short time to prevent overheating damage.

[0004] Traditional motor designs have certain limitations in the face of these requirements. Due to the large power output range and speed span of the motor, a single motor often has difficulty meeting the requirements in terms of efficiency, stability, noise and thermal management under different working conditions. In some special working conditions, such as urban cruising and high-speed driving of electric vehicles, the motor needs to be able to flexibly switch working modes to ensure efficient operation at low speeds and strong power output at high speeds.

[0005] To overcome this problem, some design solutions have proposed the dual-motor drive method, but there are still the following key defects:

[0006] For example, the dual-motor device disclosed in the patent document CN110843493A realizes power coupling through an independent rotating shaft and a gear set. Although this solution can expand the speed range, it requires additional transmission components, resulting in increased mechanical losses, and the layout of two motors and two rotating shafts occupies a large space and is difficult to meet the compactness requirements.

[0007] For example, the dual-motor device disclosed in patent document CN113400953A includes two independent single-motor systems. The two motors require more space, increase the volume and weight of the system, and require two different control systems, which is contrary to the requirements of lightweight and compact design. Therefore, how to achieve a wide speed and power range in the same motor while maintaining high efficiency, low noise, low vibration and good thermal management capabilities has become an important issue that needs to be solved in the current motor design field. Summary of the invention

[0008] In order to solve the above problems, the present invention provides the following solutions:

[0009] A dual-motor device, the device comprising a large motor, a small motor and a rotating shaft, wherein the small motor comprises a small motor stator and a small motor rotor, and the large motor comprises a large motor stator and a large motor rotor;

[0010] The small motor rotor is inside the small motor stator;

[0011] The small motor stator is inside the large motor rotor;

[0012] The large motor rotor is inside the large motor stator;

[0013] The small motor rotor and the large motor rotor are both fixed on the rotating shaft.

[0014] Furthermore, the device also includes a motor housing, a tail end cover, a large motor rotor bracket, and a small motor rotor bracket;

[0015] The large motor stator is fixed on the inner side of the motor housing, the small motor stator is fixed on the inner side of the tail end cover, and the tail end cover is connected to the motor housing;

[0016] The large motor rotor is fixed on the large motor rotor bracket, the small motor rotor is fixed on the small motor rotor bracket, and the large motor rotor bracket and the small motor rotor bracket are fixed on the rotating shaft.

[0017] Further, the device also includes a tail end bearing sleeve, a tail end bearing, a tail end inner cover, an extension end cover, an extension end outer cover, an extension end bearing, an extension end bearing sleeve, an extension end inner cover and a tail end outer cover;

[0018] The tail end bearing is fixed on the tail end bearing sleeve, the extension end bearing is fixed on the extension end bearing sleeve, and the tail end bearing and the extension end bearing jointly support the rotating shaft;

[0019] The extension end outer cover and the extension end inner cover are fixed on the extension end bearing sleeve, and the extension end bearing sleeve is fixed on the extension end cover;

[0020] The tail end outer cover and the tail end inner cover are fixed on the tail end bearing sleeve, and the tail end bearing sleeve is fixed on the tail end cover.

[0021] Furthermore, the device further includes: a resolver bracket, a protective cover, a detachable transition shaft, and a resolver;

[0022] The detachable transition shaft is connected to the rotating shaft, the resolver is fixed on the detachable transition shaft, the resolver bracket is connected to the resolver, the resolver bracket extends to the outer cover at the tail end, there is a gap between the resolver bracket and the outer cover at the tail end, and the protective cover is fixed on the resolver bracket.

[0023] Furthermore, the device further includes: an inlet of the large motor cooling water circuit, a long outlet pipe joint, the large motor cooling water circuit, an upper water pipe, a short inlet pipe joint, the small motor cooling water circuit, an outlet of the large motor cooling water circuit, a short outlet pipe joint, a long return pipe joint, and a lower water pipe;

[0024] The large motor cooling water circuit, the inlet of the large motor cooling water circuit, and the outlet of the large motor cooling water circuit are embedded inside the motor housing;

[0025] The small motor cooling water circuit is embedded inside the end cover at the tail end;

[0026] The long outlet pipe joint, the large motor cooling water circuit, and the upper water pipe are communicated;

[0027] The upper water pipe is communicated with the short inlet pipe joint and the small motor cooling water circuit;

[0028] The small motor cooling water circuit, the short outlet pipe joint, and the lower water pipe are connected;

[0029] The lower water pipe, the long return pipe joint, and the large motor cooling water circuit are connected.

[0030] A control method for a dual-motor device, where the dual-motor device is any one of the dual-motor devices described in the present invention, and the method includes:

[0031] S1. Obtain the desired speed n of the dual-motor device in real time d , the stator temperature of the small motor, and the actual speed of the small motor;

[0032] S2. Determine the operating states of the small motor and the large motor:

[0033] If n d < n s1 , send a control signal to control the operation of the small motor and stop the large motor, and then return to S1;

[0034] If n d ≥ n 1max , send a control signal to control the operation of the large motor and stop the small motor, and then return to S1;

[0035] If n1s ≤ n d < n 1max , then enter S3;

[0036] Wherein, n s1 is the rated speed of the small motor, and n 1max is the maximum speed of the small motor;

[0037] S3. A step of obtaining the power saving coefficient p of the small motor according to the power of the large motor and the power of the small motor when the dual-motor device is operating at the desired speed;

[0038] S4. A step of obtaining the temperature prediction function of the stator of the small motor according to the desired speed n d of the dual-motor device, the stator temperature of the small motor, and the actual speed of the small motor;

[0039] S5. A step of obtaining the stator temperature coefficient k of the small motor during over-running according to the desired speed n d of the dual-motor device and the temperature prediction function of the stator of the small motor;

[0040] S6. A step of judging the relationship between the stator temperature coefficient k of the small motor during over-running and the power saving coefficient p of the small motor,

[0041] If k > p, send a control signal to control the operation of the large motor and stop the small motor;

[0042] If k ≤ p, send a control signal to control the operation of the small motor and stop the large motor.

[0043] A control system for a dual-motor device, the system includes:

[0044] A module for real-time obtaining of the desired speed n d of the dual-motor device, the stator temperature of the small motor, and the actual speed of the small motor;

[0045] A running state judgment module: used for judging the running states of the small motor and the large motor, and this module further includes:

[0046] A sub-module: If n d < n s1 , send a control signal to control the operation of the small motor and stop the large motor;

[0047] A sub-module: If n d ≥ n 1max , send a control signal to control the operation of the large motor and stop the small motor;

[0048] A sub-module: If n 1s ≤ n d < n 1max , start Module 1;

[0049] Module 1, configured to obtain the power saving coefficient p of the small motor according to the power of the small motor and the large motor when operating at the desired speed of the dual-motor device;

[0050] configured to obtain the stator temperature prediction function of the small motor according to the desired speed n of the dual-motor device d , the stator temperature of the small motor, and the actual speed of the small motor;

[0051] configured to obtain the stator temperature coefficient k of the small motor during overoperation according to the desired speed n of the dual-motor device d and the stator temperature prediction function of the small motor;

[0052] A judgment module, configured to judge the relationship between the stator temperature coefficient k of the small motor during overoperation and the power saving coefficient p of the small motor. This module further includes:

[0053] A sub-module: if k > p, issue a control signal to control the operation of the large motor and stop the small motor;

[0054] A sub-module: if k ≤ p, issue a control signal to control the operation of the small motor and stop the large motor.

[0055] Based on the same inventive concept, the present invention also provides a computer storage medium for storing a computer program. When the computer program is read by a computer, the computer executes the method of the present invention.

[0056] Based on the same inventive concept, the present invention also provides a computer, including a processor and a storage medium. When the processor reads the computer program stored in the storage medium, the computer executes the control method of the dual-motor device of the present invention.

[0057] Based on the same inventive concept, the present invention also provides a computer program product. As a computer program, when the computer program is read, it implements the control method of the dual-motor device of the present invention.

[0058] The present invention has the following beneficial effects:

[0059] (1) A dual-motor device proposed by the present invention has a wide power output and speed range. By integrating two drive units, a small motor and a large motor, within the same device, the present invention solves the technical problem that it is difficult for a traditional single motor to balance the requirements of low-speed high-efficiency and high-speed high-power. The small motor can operate efficiently under low-power and low-speed conditions to meet the demand for long-term low-power output; while the large motor plays a role in high-power and high-speed scenarios, providing strong power support. The two are seamlessly switched through an intelligent control method, enabling the entire system to cover a wide range of speeds and powers, thereby adapting to the complex and changeable working conditions. This multi-functional adaptation ability greatly improves the practicality of the motor device and provides a reliable technical guarantee for various working condition requirements.

[0060] (2) A dual-motor device proposed by the present invention has an innovative coaxial integration structure. Aiming at the mechanical redundancy defect of the existing dual-motor device, the present invention uses a single rotating shaft to carry the rotors of the large and small motors, and realizes the coupling of the power output of the dual motors through the nested design of the large motor and the small motor. This design overcomes the technical prejudice that a traditional dual-motor device requires a double rotating shaft or an additional transmission mechanism. While ensuring the torque transmission efficiency, the axial space is compressed to less than 50% of the traditional scheme. The coaxial nesting of the dual motors faces three challenges: the mutual penetration of the magnetic fields of the large and small motors leads to a sharp drop in efficiency, the high-speed rotation of the rotor causes a resonance risk, and the thermal expansion in a narrow space is likely to cause structural interference. The present invention creatively proposes a hierarchical magnetic shielding technology. Through the special magnetic circuit design of the stator and rotor and the asymmetric winding layout, magnetic field decoupling is achieved; an integrated rotor bracket and a dynamic balance tuning system are used to eliminate the vibration caused by uneven mass distribution; combined with the thermal expansion compensation gap design, stable operation is achieved within a millimeter-level installation space. In addition, this coaxial integration structure effectively eliminates the vibration harmonics caused by the misalignment of the double rotating shafts, thereby reducing the vibration source, realizing smooth operation in low-power output scenarios, and effectively suppressing the generation of vibration and noise. This low-noise characteristic not only improves the user experience but is also environmentally friendly and suitable for applications in noise-sensitive scenarios.

[0061] (3) The dual-motor device proposed by the present invention features a differentiated independent cooling system design. In response to the problem that the traditional single-motor cooling structure cannot adapt to the nested dual-motor, the present invention achieves precise heat dissipation through a separated waterway architecture: the cooling waterway for the large motor adopts an external sandwich spiral flow channel, maximizing the heat dissipation area using the radial space of the motor housing (1) to adapt to the large flow demand under high power; the cooling waterway for the small motor is integrated inside the tail end cover and adopts an axial microchannel design to match the mild heat dissipation demand under low-power conditions; the two cooling waterways achieve dynamic flow distribution through multiple pipe joints to avoid mutual interference between the cooling requirements of the two motors. The integrated cooling of the housing needs to solve the problems of limited flow channels, heat stress concentration, and electromagnetic interference. The present invention breakthroughly adopts the bionic fractal flow channel topology technology to maximize the heat dissipation area within a limited space; develops a carbon fiber composite housing material with both high thermal conductivity and low thermal expansion coefficient to avoid structural deformation caused by cooling temperature differences; innovatively applies a nano-insulating coating to block the eddy current path in the cooling waterway. Through multi-dimensional collaborative design, the dual improvements of high-efficiency heat dissipation and structural reliability are achieved. This design overcomes the problem of uneven heat flow distribution caused by directly applying traditional single-motor cooling structures (such as spiral water channels and axial microchannels) to the nested dual-motor of the present invention, and can quickly dissipate heat to ensure the stable operation of the motor.

[0062] (4) The dual-motor control method proposed by the present invention has efficient energy management capabilities. In response to the energy consumption characteristics under different working conditions, by real-time monitoring and analyzing the operating states, temperature changes, and power demands of the small motor and the large motor, the working mode is dynamically adjusted. When the rotational speed demand is low, the small motor operates independently to minimize energy consumption; while when the power demand is high, the large motor starts to operate to meet the short-term high-load requirements. In addition, based on the judgment method of the power saving coefficient and the temperature coefficient, the present invention can accurately control the switching timing of the motor, further optimizing the energy distribution efficiency. This efficient energy management method significantly reduces the operating cost of the device and extends the service life of the motor.

[0063] (5) The dual-motor control method proposed by the present invention, by real-time judging the desired rotational speed and the motor performance boundary, preferentially enables the small motor to operate independently in the low rotational speed range, switches to the large motor to dominate in the high rotational speed range, and dynamically evaluates the power saving coefficient in the medium rotational speed range to achieve the optimal efficiency mode selection. Combining the torque coupling characteristics of the coaxial structure, it avoids the mechanical losses of the traditional dual-motor system and significantly improves the energy efficiency utilization rate.

[0064] (6) The dual-motor control method proposed by the present invention, based on the small motor stator temperature prediction function, uses historical operating data to predict the temperature rise trend and dynamically adjusts the operating mode threshold. When the temperature coefficient exceeds the power saving benefit, it is forced to switch to the large motor for operation, breaking through the lag defect of traditional temperature feedback and ensuring that key components operate within a safe temperature range.

[0065] (7) A dual-motor control method proposed by the present invention constructs a motor degradation model based on historical operation data and dynamically corrects threshold parameters such as rated speed and maximum speed, which can extend the service life of key components.

[0066] The present invention is applicable to fields with high requirements for multi-condition adaptability such as electric vehicles and ship drives. Especially in scenarios where high efficiency, low noise, and high power output need to be considered, it can provide excellent solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 is a dual-motor device described in Embodiment 1; Reference numerals: motor housing 1; large-motor cooling water inlet 2; long outlet pipe joint 3; large-motor cooling water path 4; upper water pipe 5; tail end cover 6; short inlet pipe joint 7; small-motor cooling water path 8; tail end bearing sleeve 9; resolver bracket 10; protective cover 11; tail end bearing 12; tail end inner cover 13; small-motor stator 14; small-motor rotor 15; large-motor cooling water outlet 16; large-motor stator 17; large-motor rotor bracket 18; large-motor internal space 19; small-motor rotor bracket 20; extension end cover 21; extension end outer cover 22; rotating shaft 23; extension end bearing 24; extension end bearing sleeve 25; extension end inner cover 26; no original 27 serial number; short outlet pipe joint 28; long return water pipe joint 29; detachable transition shaft 30; large-motor rotor 31; lower water pipe 32; resolver 33; tail end outer cover 34;

[0068] Figure 2 is an expanded view of the large-motor cooling water path described in Embodiment 7;

[0069] Figure 3 is an expanded view of the small-motor cooling water path described in Embodiment 7;

[0070] Figure 4 is a flowchart of a dual-motor control method described in Embodiment 7. Embodiment

[0072] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0073] Embodiment 1

[0074] In conjunction with the attached Figure 1Description of this embodiment: A dual-motor device, the device includes a large motor, a small motor and a rotating shaft 23, wherein the small motor includes a small motor stator 14 and a small motor rotor 15, and the large motor includes a large motor stator 17 and a large motor rotor 31;

[0075] The small motor rotor 15 is inside the small motor stator 14;

[0076] The small motor stator 14 is inside the large motor rotor 31;

[0077] The large motor rotor 31 is inside the large motor stator 17;

[0078] Both the small motor rotor 15 and the large motor rotor 31 are fixed on the rotating shaft 23.

[0079] In this embodiment, by arranging the small motor rotor 15 inside the small motor stator 14, the small motor stator 14 inside the large motor rotor 31, the large motor rotor 31 inside the large motor stator 17, and fixing both the small motor rotor 15 and the large motor rotor 31 on the rotating shaft 23, the technical means of coaxial nested layout of the dual motors is achieved. This structural design enables the large motor and the small motor to share the same rotating shaft, realizing a compact space layout, reducing the overall volume and weight of the device. At the same time, the nested design of the dual motors can effectively improve the power density, meet the high-power output requirements, and is suitable for scenarios with strict requirements for space and weight, such as new energy vehicles or the aerospace field. In addition, the coaxial design simplifies the transmission structure, reduces mechanical losses, and improves the energy transfer efficiency, having the effects of simple structure, stable operation, energy saving and high efficiency.

[0080] Embodiment Two

[0081] This embodiment is a further limitation of Embodiment One. Further, the device further includes a motor housing 1, a tail end cover 6, a large motor rotor bracket 18, a small motor rotor bracket 20;

[0082] The large motor stator 17 is fixed on the inner side of the motor housing 1, the small motor stator 14 is fixed on the inner side of the tail end cover 6, and the tail end cover 6 is connected to the motor housing 1;

[0083] The large motor rotor 31 is fixed on the large motor rotor bracket 18, the small motor rotor 15 is fixed on the small motor rotor bracket 20, and the large motor rotor bracket 18 and the small motor rotor bracket 20 are fixed on the rotating shaft 23.

[0084] In this embodiment, on the basis of Embodiment 1, a motor housing 1, a tail end cover 6, a large motor rotor bracket 18, and a small motor rotor bracket 20 are added, and the large motor stator 17 is fixed inside the motor housing 1, and the small motor stator 14 is fixed inside the tail end cover 6, achieving a modular fixing technical means for the double motor stator and rotor. This design enables the independent installation and fixing of the stators and rotors of the large motor and the small motor, improving the assembly efficiency and maintenance convenience of the device. At the same time, through the connection between the tail end cover 6 and the motor housing 1, the rigidity and sealing performance of the overall structure are enhanced, effectively preventing external pollutants such as dust and moisture from entering the motor interior and extending the service life of the device. In addition, the design of the rotor bracket ensures the stable connection between the rotor and the rotating shaft 23, reducing vibration and noise during operation, and having the effects of convenient assembly, stable structure, and strong protection.

[0085] Embodiment 3

[0086] This embodiment further limits Embodiment 2. Further, the device further includes a tail end bearing sleeve 9, a tail end bearing 12, a tail end inner cover 13, an extension end cover 21, an extension end outer cover 22, an extension end bearing 24, an extension end bearing sleeve 25, an extension end inner cover 26, and a tail end outer cover 34;

[0087] The tail end bearing 12 is fixed on the tail end bearing sleeve 9, the extension end bearing 24 is fixed on the extension end bearing sleeve 25, and the tail end bearing 12 and the extension end bearing 24 jointly support the rotating shaft 23;

[0088] The extension end outer cover 22 and the extension end inner cover 26 are fixed on the extension end bearing sleeve 25, and the extension end bearing sleeve 25 is fixed on the extension end cover 21;

[0089] The tail end outer cover 34 and the tail end inner cover 13 are fixed on the tail end bearing sleeve 9, and the tail end bearing sleeve 9 is fixed on the tail end cover 6.

[0090] In this embodiment, on the basis of Embodiment 2, a tail end bearing sleeve 9, a tail end bearing 12, an extension end bearing sleeve 25, an extension end bearing 24, and related end cover structures are added, achieving a technical means for double-end support and sealing protection of the rotating shaft 23. Through the joint support of the tail end bearing 12 and the extension end bearing 24, the operation of the rotating shaft 23 is more stable, reducing wear and vibration caused by uneven bearing force, and improving the operation reliability and service life of the device. At the same time, the designs of the extension end outer cover 22, the extension end inner cover 26, the tail end outer cover 34, and the tail end inner cover 13 further enhance the sealing performance of the device, preventing lubricating grease leakage and external pollutant intrusion, and ensuring the cleanliness inside the motor. In addition, the fixed connection method between the bearing sleeve and the end cover simplifies the assembly process, reduces production costs, and has the effects of stable operation, good sealing performance, and simple assembly.

[0091] Embodiment 4

[0092] This embodiment further limits Embodiment 2 or 3. Further, the device further includes: a resolver bracket 10, a protective cover 11, a detachable transition shaft 30, and a resolver 33;

[0093] The detachable transition shaft 30 is connected to the rotating shaft 23, the resolver 33 is fixed on the detachable transition shaft 30, the resolver bracket 10 is connected to the resolver 33, the resolver bracket 10 extends to the outer cover 34 at the tail end, there is a gap between the resolver bracket 10 and the outer cover 34 at the tail end, and the protective cover 11 is fixed on the resolver bracket 10.

[0094] By adding the resolver bracket 10, the protective cover 11, the detachable transition shaft 30, and the resolver 33 on the basis of Embodiment 3, this embodiment achieves the technical means of accurately detecting and protecting the rotor position and speed. The resolver 33 is connected to the rotating shaft 23 through the detachable transition shaft 30, which can monitor the position and speed of the rotor in real time, provide data support for the precise control of the motor, and improve the control accuracy and response speed of the device. The design of the resolver bracket 10 and the protective cover 11 not only ensures the stable installation of the resolver 33 but also provides effective protection for it, preventing the influence of external impact or vibration on the detection accuracy. In addition, the design of the detachable transition shaft 30 facilitates the maintenance and replacement of the resolver 33, reduces the maintenance cost, and has the effects of high detection accuracy, strong protection, and convenient maintenance.

[0095] Embodiment 5

[0096] This embodiment further limits any of the foregoing embodiments. Further, the device further includes: a large motor cooling water inlet 2, an outlet long pipe joint 3, a large motor cooling water path 4, an upper water pipe 5, an inlet short pipe joint 7, a small motor cooling water path 8, a large motor cooling water outlet 16, an outlet short pipe joint 28, a return water long pipe joint 29, and a lower water pipe 32;

[0097] The large motor cooling water path 4, the large motor cooling water inlet 2, and the large motor cooling water outlet 16 are embedded in the motor housing 1;

[0098] The small motor cooling water path 8 is embedded in the tail end cover 6;

[0099] The outlet long pipe joint 3, the large motor cooling water path 4, and the upper water pipe 5 are connected;

[0100] The upper water pipe 5 is connected to the inlet short pipe joint 7 and the small motor cooling water path 8;

[0101] The small motor cooling water path 8, the outlet short pipe joint 28, and the lower water pipe 32 are connected;

[0102] The sewer pipe 32, the return water long pipe joint 29 and the large motor cooling water path 4 are connected.

[0103] In this embodiment, by adding the large motor cooling water path 4, the small motor cooling water path 8 and related water path connection structures on the basis of the foregoing embodiment, the technical means of efficient cooling of the dual motors is achieved. The large motor cooling water path 4 is embedded inside the motor housing 1, and the small motor cooling water path 8 is embedded inside the tail end cover 6. The circulating flow of the cooling water is realized through connectors such as the water outlet long pipe joint 3 and the water inlet short pipe joint 7, effectively taking away the heat generated during the operation of the motor and preventing the motor from overheating. This cooling method not only improves the cooling efficiency but also avoids the disadvantage of being easily affected by the environment in the traditional air cooling method, and is applicable to harsh environments such as high temperature and high humidity. In addition, the design of the cooling water path is highly integrated with the motor structure, reducing the dependence on external cooling equipment, and having the effects of high cooling efficiency, strong adaptability and compact structure.

[0104] Embodiment Six

[0105] A control method for a dual motor device, where the dual motor device is the dual motor device described in any of the foregoing embodiments, and the method includes:

[0106] S1. Obtain the desired speed n of the dual motor device in real time d , the stator temperature of the small motor, and the actual speed of the small motor;

[0107] S2. Determine the operating states of the small motor and the large motor:

[0108] If n d < n s1 , send a control signal to control the operation of the small motor and stop the large motor, and then return to S1;

[0109] If n d ≥ n 1max , send a control signal to control the operation of the large motor and stop the small motor, and then return to S1;

[0110] If n 1s ≤ n d < n 1max , then enter S3;

[0111] Wherein, n s1 is the rated speed of the small motor, and n 1max is the maximum speed of the small motor;

[0112] S3. Obtain the power saving coefficient p of the small motor according to the power of the large motor and the power of the small motor when the dual motor device is operating at the desired speed;

[0113] S4. Steps for obtaining the temperature prediction function of the small motor stator based on the desired speed n of the dual-motor device, d the stator temperature of the small motor, and the actual speed of the small motor;

[0114] S5. Steps for obtaining the stator temperature coefficient k of the small motor during overoperation based on the desired speed n d of the dual-motor device and the temperature prediction function of the small motor stator;

[0115] S6. Steps for determining the relationship between the stator temperature coefficient k of the small motor during overoperation and the power saving coefficient p of the small motor,

[0116] if k > p, send a control signal to control the operation of the large motor and stop the small motor;

[0117] if k ≤ p, send a control signal to control the operation of the small motor and stop the large motor.

[0118] In this embodiment, by providing a control method for a dual-motor device, a technical means of intelligently switching the operating states of the large motor and the small motor according to the actual working conditions is achieved. By real-time obtaining the desired speed of the dual-motor device, the stator temperature of the small motor, and the actual speed of the small motor, and combining with the power coefficient and the temperature prediction function, accurate judgment and control of the operating states of the small motor and the large motor are realized. This method can avoid damage to the small motor caused by overheating or overloading during operation while ensuring the efficient operation of the device, and prolong the service life of the motor. In addition, by intelligently switching the operating states of the large motor and the small motor, the energy consumption can be significantly reduced, the energy utilization rate can be improved, and it is applicable to application scenarios with high energy efficiency requirements, having the effects of accurate control, energy saving and high efficiency, and extended service life.

[0119] Embodiment Seven

[0120] This embodiment combines the technical solutions described in the foregoing multiple embodiments, and through specific embodiments, further verifies and explains the technical effects of the present invention in combination with the actual situation:

[0121] As Figure 1 shown, a dual-motor device includes a motor housing 1, a tail end cover 6, a tail end bearing sleeve 9, a tail end bearing 12, a tail end inner cover 13, a small motor stator 14, a small motor rotor 15, a large motor stator 17, a large motor rotor bracket 18, a small motor rotor bracket 20, an extension end cover 21, an extension end outer cover 22, a rotating shaft 23, an extension end bearing 24, an extension end bearing sleeve 25, an extension end inner cover 26, a large motor rotor 31, and a tail end outer cover 34.

[0122] The large motor stator 17 is fixed inside the motor housing 1, the small motor stator 14 is fixed on the inner side of the tail end cover 6, and the tail end cover 6 is connected to the motor housing 1.

[0123] The large motor rotor 31 is fixed on the large motor rotor bracket 18, the small motor rotor 15 is fixed on the small motor rotor bracket 20, and the large motor rotor bracket 18 and the small motor rotor bracket 20 are fixed on the rotating shaft 23.

[0124] The rotating shaft 23 is supported by an extension end bearing 24 and a tail end bearing 12, and the extension end bearing 24 and the tail end bearing 12 are respectively fixed in an extension end bearing sleeve 25 and a tail end bearing sleeve 9.

[0125] The extension end outer cover 22 and the extension end inner cover 26 are fixed on the extension end bearing sleeve 25, and the extension end bearing sleeve 25 is fixed on the extension end cover 21.

[0126] The tail end outer cover 34 and the tail end inner cover 13 are fixed on the tail end bearing sleeve 9, and the tail end bearing sleeve 9 is fixed on the tail end cover 6.

[0127] A dual-motor device further includes a resolver bracket 10, a protective cover 11, a detachable transition shaft 30, and a resolver 33.

[0128] The resolver 33 is used to measure the actual rotational speed of the motor. When the resolver 33 is needed, the detachable transition shaft 30 is connected to the shaft 23, the resolver 33 is fixed on the transition shaft 30, the resolver bracket 10 is connected to the resolver 33, the resolver bracket 10 extends to the tail end bearing outer cover 34, there is a gap between the resolver bracket 10 and the tail end bearing outer cover 34, and the protective cover 11 is fixed on the resolver bracket 10.

[0129] When the resolver 33 is not needed, the detachable transition shaft 30, the resolver bracket 10, and the resolver 33 can be removed, and the protective cover 11 is directly fixed on the tail end bearing outer cover 34.

[0130] As Figures 2 - 3 shown, a dual-motor device further includes a large motor cooling water inlet 2, a long outlet pipe joint 3, a large motor cooling water path 4, an upper water pipe 5, a short inlet pipe joint 7, a small motor cooling water path 8, a large motor cooling water outlet 16, a large motor internal space 19, a short outlet pipe joint 28, a long return pipe joint 29, and a lower water pipe 32.

[0131] The motor housing 1 is provided with a large motor cooling water path 4, a large motor cooling water inlet 2, and a large motor cooling water outlet 16. The tail end cover 6 is provided with a small motor cooling water path 8.

[0132] The large motor cooling water inlet 2 is used as an inlet to introduce water into the cooling water path 4.

[0133] The long outlet pipe joint 3 passes through the tail end cover 6 and is connected to the large motor cooling water circuit 4, and the other end is connected to the upper water pipe 5. One end of the short inlet pipe joint 7 is connected to the small motor cooling water circuit 8, and the other end is connected to the upper water pipe 5.

[0134] One end of the short outlet pipe joint 28 is connected to the small motor cooling water circuit 8, and the other end is connected to the lower water pipe 32. The long return pipe joint 29 passes through the tail end cover 6 and is connected to the large motor cooling water circuit 4, and the other end is connected to the lower water pipe 32.

[0135] Cooling water enters the large motor cooling water circuit 4 through the large motor cooling water circuit inlet 2. Most of the cooling water directly flows out from the large motor cooling water circuit outlet 16 through the large motor cooling water circuit 4, and a small part of the cooling water sequentially passes through the long outlet pipe joint 3, the upper water pipe 5, and the short inlet pipe joint 7 and flows into the small motor cooling water circuit 8.

[0136] The cooling water flowing into the small motor cooling water circuit 8 sequentially passes through the small motor cooling water circuit 8, the short outlet pipe joint 28, the lower water pipe 32, and the long return pipe joint 29, and then flows back into the large motor cooling water circuit 4 and flows out from the large motor cooling water circuit outlet 16.

[0137] The structure of the tail end cover 6 extends into the large motor internal space 19. The small motor stator 14 is fixed on the inner side of the tail end cover 6, and the small motor stator 14 and the small motor rotor 15 extend into the large motor internal space 19.

[0138] When the small motor rotor 15 rotates, the generated electromagnetic force acts on the small motor stator 14 and is transmitted to the machine shell 1 through the tail end cover 6, increasing the vibration propagation path and effectively reducing the vibration value of the motor.

[0139] The small motor of the present invention is composed of a small motor rotor 15 and a small motor stator 14. The large motor is composed of a large motor rotor 31 and a large motor stator 17. It can meet the requirements of both small power, low speed working conditions and large power, high speed working conditions. When it is necessary to operate under small power, low speed working conditions, the small motor rotor 15 drives the rotating shaft 23 to rotate. When it is necessary to operate under large power, high speed working conditions, the large motor rotor 31 drives the rotating shaft 23 to rotate. The small motor rotor 15 and the large motor rotor 31 do not rotate actively at the same time.

[0140] As Figure 4 shown, a dual-motor control method, the method is implemented based on the dual-motor device of the present invention, and the dual-motor is controlled according to information such as the desired speed, power prediction function, predicted motor stator temperature function, etc. The specific method is as follows:

[0141] The functional relationship between the actual speed and power of the small motor is:

[0142] P1 = a1n12 +b1n1+c1(1)

[0143] Wherein:

[0144] P1 is the power of the small motor running at the actual speed;

[0145] n1 is the actual speed of the small motor;

[0146] a1, b1, c1 are function fitting coefficients.

[0147] The functional relationship between the speed and power of the large motor is:

[0148] P2 = a2n2 2 +b2n2+c2(2)

[0149] Wherein:

[0150] P2 is the power of the large motor running at the actual speed;

[0151] n2 is the actual speed of the large motor;

[0152] a2, b2, c2 are function fitting coefficients.

[0153] Step 1: Determine the relationship between the current desired speed n d and the rated speed n s1 of the small motor, the maximum allowable speed n 1max of the small motor. The maximum allowable speed n 1max of the small motor is:

[0154] n 1max =δn d (3)

[0155] where δ>1 is the excess coefficient.

[0156] If n d <n s1 , the small motor runs and the large motor does not run.

[0157] If n d ≥n 1max , the large motor runs and the small motor does not run.

[0158] If n 1s ≤n d <n 1max , go to Step 2.

[0159] Step 2:

[0160] Substitute n1 = n d into Equation (1) to obtain the power P1 of the small motor running at the speed of n d .

[0161] Substitute \(n_2 = n\) d into Equation (2), and the power \(P_2\) of the large motor running at speed \(n\) is obtained. d

[0162] Estimate the power saving coefficient \(p\) when the small motor runs at speed \(n\) d :

[0163] \(p=\lambda_1(P_2 - P_1) / P_2\) (4)

[0164] where \(\lambda_1\) is the adjustment coefficient.

[0165] Step 3:

[0166] Given the expected speeds \(n\) di , \(i = 1,\cdots,n\)

[0167] and the stator temperatures \(K\) of the small motor at the previous \(n\) moments 1i , \(i = 1,\cdots,n\)

[0168] Then the average stator temperature at the previous \(n\) moments is

[0169] The average expected speed at the previous \(n\) moments is

[0170] The estimated function of the small motor stator temperature is:

[0171] \(K_1 = an\) d + b (5)

[0172] where \(a\) and \(b\) are the coefficients of the estimated function of the small motor stator temperature:

[0173]

[0174] Given the current stator temperature \(K\) of the small motor 1t and the actual speed \(n\) of the current small motor 1t . Substitute \(n\) d = \(n\) 1t into Equation (5), and the estimated stator temperature \(K\) 1t ' of the small motor at the current moment is obtained. The estimation error of the current stator temperature of the small motor is:

[0175] \(\alpha\) 1t = \(K\) 1t - \(K\) 1t ' (7)

[0176] Revise the coefficient \(a\) of the estimated function of the small motor stator temperature. The revision amount \(\Delta a\) of the coefficient \(a\) is:

[0177] ​

[0178] Among them, λ is the weight coefficient.

[0179] The coefficient a of the small motor stator temperature prediction function is corrected to:

[0180] a′ = a + Δa (9)

[0181] The corrected small motor stator temperature prediction function is:

[0182] K1′ = a′n d + b (10)

[0183] Step 4: Substitute the current desired speed n d into the corrected small motor stator temperature prediction function to obtain the predicted stator temperature K1′. The upper limit value of the small motor stator temperature is K 1max , the preset temperature warning value K p , and calculate the stator temperature coefficient k when the small motor operates overloaded:

[0184]

[0185] Among them, ρ ∈ (0, 0.3) is the small motor stator temperature safety factor.

[0186] Step 5: Judge the relationship between the stator temperature coefficient k and the saved power coefficient p. If k > p, it means that the temperature coefficient exceeds the saved power coefficient, then the large motor operates and the small motor does not operate. If k ≤ p, it means that the saved power coefficient exceeds the temperature coefficient, then the small motor operates and the large motor does not operate.

[0187] The technical solutions provided by the present invention are further described in detail through the above several specific embodiments to highlight the advantages and beneficial effects of the technical solutions provided by the present invention. However, the above several specific embodiments are not used as limitations to the present invention. Any reasonable modifications and improvements, combinations of embodiments, and equivalent replacements based on the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0188] Those skilled in the art can understand that the above is only the preferred embodiment of the present invention. The features described in each embodiment and / or claim of the present disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly recorded in the present disclosure. It is not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0189] Although the preferred embodiments of the present invention have been described, additional changes and modifications can be made by those skilled in the art once they learn the basic creative concept. Therefore, the appended claims are intended to be interpreted to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art can make various changes and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A dual motor device, characterized in that: The device comprises a large motor, a small motor and a rotating shaft (23), wherein the small motor comprises a small motor stator (14) and a small motor rotor (15), and the large motor comprises a large motor stator (17) and a large motor rotor (31); The small motor rotor (15) is inside the small motor stator (14); The small motor stator (14) is inside the large motor rotor (31); The large motor rotor (31) is inside the large motor stator (17); The small motor rotor (15) and the large motor rotor (31) are both fixed on the rotating shaft (23).

2. The device according to claim 1, characterized in that The device also includes a motor housing (1), a tail end cover (6), a large motor rotor bracket (18), and a small motor rotor bracket (20); The large motor stator (17) is fixed on the inner side of the motor housing (1), and the small motor stator (14) is fixed on the inner side of the tail end cover (6), and the tail end cover (6) is connected to the motor housing (1); The large motor rotor (31) is fixed on a large motor rotor bracket (18), the small motor rotor (15) is fixed on a small motor rotor bracket (20), and the large motor rotor bracket (18) and the small motor rotor bracket (20) are fixed on a rotating shaft (23).

3. The device according to claim 2, characterized in that The device further comprises a tail end bearing sleeve (9), a tail end bearing (12), a tail end inner cover (13), an extension end cover (21), an extension end outer cover (22), an extension end bearing (24), an extension end bearing sleeve (25), an extension end inner cover (26) and a tail end outer cover (34); The tail end bearing (12) is fixed on the tail end bearing sleeve (9), and the extension end bearing (24) is fixed on the extension end bearing sleeve (25), and the tail end bearing (12) and the extension end bearing (24) jointly support the rotating shaft (23); The extension end outer cover (22) and the extension end inner cover (26) are fixed on the extension end bearing sleeve (25), and the extension end bearing sleeve (25) is fixed on the extension end cover (21); The tail end outer cover (34) and the tail end inner cover (13) are fixed on the tail end bearing sleeve (9), and the tail end bearing sleeve (9) is fixed on the tail end cover (6).

4. The device according to claim 3, characterized in that The device further comprises: a rotary transformer bracket (10), a protective cover (11), a detachable transition shaft (30) and a rotary transformer (33); The detachable transition shaft (30) is connected to the rotating shaft (23), the rotary transformer (33) is fixed on the detachable transition shaft (30), the rotary transformer bracket (10) is connected to the rotary transformer (33), the rotary transformer bracket (10) extends to the tail end outer cover (34), there is a gap between the rotary transformer bracket (10) and the tail end outer cover (34), and the protective cover (11) is fixed on the rotary transformer bracket (10).

5. The device according to claim 4, characterized in that The device further comprises: a large motor cooling water circuit water inlet (2), a water outlet long pipe joint (3), a large motor cooling water circuit (4), an upper water pipe (5), a water inlet short pipe joint (7), a small motor cooling water circuit (8), a large motor cooling water circuit water outlet (16), a water outlet short pipe joint (28), a return water long pipe joint (29) and a lower water pipe (32); The large motor cooling water circuit (4), the large motor cooling water circuit water inlet (2) and the large motor cooling water circuit water outlet (16) are embedded in the motor housing (1); The small motor cooling water circuit (8) is embedded in the tail end cover (6); The water outlet long pipe joint (3), the large motor cooling water circuit (4) and the upper water pipe (5) are connected; The upper water pipe (5) is connected to the water inlet short pipe joint (7) and the small motor cooling water circuit (8); The small motor cooling water circuit (8), the water outlet short pipe joint (28) and the down pipe (32) are connected; The down pipe (32), the return water long pipe joint (29) and the large motor cooling water circuit (4) are connected.

6. A control method for a dual motor device, characterized in that: The dual-motor device is the dual-motor device according to any one of claims 1 to 5, and the method comprises: S1. Obtain the expected speed n of the dual motor device in real time d , the stator temperature of the small motor, and the actual speed of the small motor; S2. Steps for determining the operating status of the small motor and the large motor: If n d <n s1 , send out a control signal to control the small motor to run and the large motor to stop, and then return to S1; If n d ≥n 1max , send out a control signal to control the large motor to run and the small motor to stop, and then return to S1; If n 1s ≤n d <n 1max , then enter S3; Among them, n s1 is the rated speed of the small motor, n 1max is the maximum speed of the small motor; S3, a step of obtaining a power coefficient p saved by the small motor according to the power of the large motor and the power of the small motor when the dual-motor device is running at a desired speed; S4, according to the expected speed n of the dual motor device d , the stator temperature of the small motor, the actual speed of the small motor, and the step of obtaining a temperature estimation function of the stator of the small motor; S5, according to the expected speed n of the dual motor device d and a temperature estimation function of the stator of the small motor, and a step of obtaining a stator temperature coefficient k when the small motor is in excess operation; S6, a step of determining the relationship between the stator temperature coefficient k when the small motor is in excess operation and the power coefficient p saved by the small motor, If k>p, a control signal is sent to control the large motor to run and the small motor to stop; If k≤p, a control signal is sent to control the small motor to run and the large motor to stop.

7. A control system for a dual motor device, characterized in that: The system comprises: Used to obtain the expected speed n of the dual motor device in real time d , the stator temperature of the small motor, and the actual speed module of the small motor; The module for judging the running status is used to judge the running status of the small motor and the large motor. The module further includes: Submodule: If n d <n s1 , sending out a control signal to control the small motor to run and the large motor to stop; Submodule: If n d ≥n 1max , sending out a control signal to control the large motor to run and the small motor to stop; Submodule: If n 1s ≤n d <n 1max , start module one; Module 1 is used to obtain the power coefficient p saved by the small motor according to the power of the small motor and the large motor when the dual motor device is running at the expected speed; For the desired speed n of the dual motor arrangement d , the stator temperature of the small motor, the actual speed of the small motor, and a module for obtaining a temperature estimation function of the stator of the small motor; For the desired speed n of the dual motor arrangement d and the temperature estimation function of the small motor stator, a module for obtaining the stator temperature coefficient k when the small motor is in excess operation; A judgment module is used to judge the relationship between the stator temperature coefficient k and the power coefficient p saved by the small motor when the small motor is in excess operation. The module further includes: Submodule: If k>p, a control signal is sent to control the large motor to run and the small motor to stop; Submodule: If k≤p, send a control signal to control the small motor to run and the large motor to stop.

8. A computer storage medium for storing a computer program, characterized in that: When the computer program is read by a computer, the computer executes the method according to claim 6.

9. A computer, comprising a processor and a storage medium, characterized in that: When the processor reads the computer program stored in the storage medium, the computer executes the method of claim 6 .

10. A computer program product, being a computer program, characterized in that When the computer program is read, the method according to claim 6 is implemented.

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