Top drive liquid-cooled motor, top drive motor liquid cooling system and feedback control method

Abstract

The application discloses a top drive liquid-cooled motor, a top drive motor liquid cooling system and a feedback control method. The top drive liquid-cooled motor comprises a motor shell, a motor stator, a motor rotor, a hollow rotor rotating shaft and upper and lower end bearing chambers, and the shell is internally provided with upper and lower end cooling chambers. The motor upper end is provided with a cooling liquid inlet communicated with the upper end bearing chamber, and the lower end is provided with a cooling liquid outlet; the rotor rotating shaft is internally formed with an axially extending main cooling flow channel, and is provided with a first shunt passage and a second shunt passage respectively communicated with the upper and lower end cooling chambers. The cooling liquid enters the main cooling flow channel through the upper end bearing chamber, is shunted to cool the upper and lower ends of the rotor, the upper and lower ends of the stator winding and the inner wall of the motor shell, and the remaining cooling liquid enters the lower end bearing chamber, and each cooling liquid is collected and discharged at the lower end. The application expands the cooling coverage range of the motor liquid cooling structure, realizes the collaborative heat dissipation of the rotor end, the stator winding end, the upper and lower end bearings and the motor shell, and reduces the cooling blind area and heat accumulation.

Description

Technical Field

[0001] This invention relates to the field of oil drilling and production equipment technology, and more specifically, to a top drive liquid-cooled motor, a top drive motor liquid cooling system, and a feedback control method. Background Technology

[0002] In top drive systems for oil drilling (referred to as top drives), the electric motor is the core power component. Currently, top drives mostly use three-phase asynchronous or permanent magnet synchronous motors, equipped with forced air cooling systems. While these motors have advantages such as a wide constant power range and high efficiency, they are typically large and heavy to meet drilling power requirements, and the air cooling system has significant drawbacks: cooling efficiency is easily affected by air density and ambient temperature, and efficiency decreases at high altitudes or in high-temperature environments. In addition, the fan connection structure is prone to loosening under long-term severe vibration, leading to air duct seal failure, reduced heat dissipation efficiency, and the high-speed airflow inside the fan can also strip the insulation layer from the winding surface, causing insulation failure, damaging the motor, and greatly increasing the risk of top drive failure.

[0003] Liquid-cooled motors, with their advantages of efficient heat dissipation, high power density, and reliability, have been applied in various fields such as automotive, aerospace, and industrial automation. However, in the drilling industry, existing liquid cooling solutions for top drive motors are not only limited but also have certain shortcomings. For example, the liquid-cooled motor cooling channel in the top drive drilling liquid-cooled motor of patent CN220291787U can only cool the stator shell and cannot effectively cover key heat sources such as the rotor and bearings. Its efficiency is limited under the high heat load of drilling, and its system integration and intelligence level are also low.

[0004] Therefore, existing air-cooling solutions suffer from poor environmental adaptability and insufficient reliability, while liquid-cooling solutions have cooling blind spots and fail to achieve deep integration with the top drive unit. Currently, there is still a lack of integrated liquid-cooling systems that can provide all-round and efficient cooling for the motor under the specific operating conditions of the top drive. There is an urgent need for a solution that can simultaneously and collaboratively dissipate heat from the motor stator, rotor, and bearings. Summary of the Invention

[0005] In order to solve at least one of the technical problems in the background art, the present invention proposes a top-drive liquid-cooled motor, a top-drive motor liquid-cooling system, and a feedback control method.

[0006] In one aspect, the present invention provides a top-drive liquid-cooled motor, the top-drive liquid-cooled motor comprising: a motor housing, a motor stator and a motor rotor disposed within the motor housing, a rotor shaft passing through the motor rotor and extending in a vertical direction, and an upper bearing chamber and a lower bearing chamber respectively disposed at the upper and lower ends of the rotor shaft, the motor stator comprising a stator core and a stator winding disposed on the stator core; The motor housing is provided with an upper cooling chamber and a lower cooling chamber. The upper end of the top-drive liquid-cooled motor is provided with a coolant inlet that communicates with the upper bearing chamber, and the lower end of the top-drive liquid-cooled motor is provided with a coolant outlet. The rotor shaft is a hollow structure, and a main cooling channel extending axially along the rotor shaft is formed inside the rotor shaft. The upper bearing chamber is connected to the upper end of the main cooling channel so that the coolant entering from the coolant inlet flows through the upper bearing chamber and then enters the main cooling channel. The rotor shaft is provided with a first flow divider channel and a second flow divider channel at different axial positions. The first flow divider channel and the second flow divider channel extend from the main cooling channel to the outer periphery of the rotor shaft. The first flow divider channel is connected to the upper cooling chamber, and the second flow divider channel is connected to the lower cooling chamber. The upper cooling chamber is provided corresponding to the upper end of the motor rotor and the upper end of the stator winding, so that the coolant flowing in through the first diversion channel cools the upper end of the motor rotor, the upper end of the stator winding, and the upper inner wall of the motor housing; the lower cooling chamber is provided corresponding to the lower end of the motor rotor and the lower end of the stator winding, so that the coolant flowing in through the second diversion channel cools the lower end of the motor rotor, the lower end of the stator winding, and the lower inner wall of the motor housing. The lower end of the main cooling channel is connected to the lower bearing chamber so that the coolant that continues to flow along the main cooling channel after being diverted by the first diversion channel and the second diversion channel enters the lower bearing chamber. The coolant flowing through the upper cooling chamber, the lower cooling chamber, and the lower bearing chamber is collected at the lower end of the top-drive liquid-cooled motor and discharged through the coolant outlet.

[0007] In another aspect, the present invention provides a top drive motor liquid cooling system, which includes: the aforementioned top drive liquid-cooled motor, coolant circulation loop, data acquisition layer, intelligent control and decision-making layer, and execution and regulation layer; The coolant circulation loop includes a low-temperature coolant tank, a lower coolant tank, a high-temperature coolant tank, a circulation pump, a heat exchanger, a filter, and connecting pipes. The low-temperature coolant tank is connected to the coolant inlet of the top-drive liquid-cooled motor, the coolant outlet of the top-drive liquid-cooled motor is connected to the lower coolant tank, the lower coolant tank is connected to the high-temperature coolant tank, and the high-temperature coolant tank is connected to the low-temperature coolant tank via the heat exchanger and the filter, thereby forming a closed loop. The circulation pump is installed in the coolant circulation loop to drive the coolant circulation. The data acquisition layer is used to acquire motor status data of the top-drive liquid-cooled motor and loop status data of the coolant circulation loop, and to receive top-drive operating condition signals. The motor status data includes stator winding temperature data, upper bearing temperature data, and lower bearing temperature data. The loop status data includes coolant temperature data at the coolant inlet and outlet, pressure data and flow data in the coolant circulation loop, and liquid level data of the low-temperature coolant tank and the high-temperature coolant tank. The intelligent control and decision-making layer is communicatively connected to the data acquisition layer and the execution and regulation layer, respectively, and is used to generate cooling regulation commands based on the motor status data, the circuit status data and the top drive condition signal; The execution and regulation layer includes a flow and direction control unit and a power and heat exchange unit. The flow and direction control unit is located in the coolant circulation loop and is used to adjust the flow rate and flow path of the coolant according to the cooling regulation command. The power and heat exchange unit includes the circulation pump and the heat exchanger and is used to control the operation of the circulation pump according to the cooling regulation command and to regulate the coolant temperature through the heat exchanger.

[0008] In another aspect, the present invention provides a feedback control method applied to the aforementioned top drive motor liquid cooling system, the feedback control method comprising: Acquire the top drive operating condition signal and determine the top drive operating status based on the top drive operating condition signal; The corresponding cooling mode is determined based on the top drive working state, and the target temperature of the coolant, the reference flow rate of the coolant, and the initial control parameters corresponding to the cooling mode are obtained. The initial control parameters include the initial proportional coefficient, the initial integral coefficient, and the initial derivative coefficient. The real-time temperature of the coolant collected by the data acquisition layer is obtained, and the temperature deviation is determined based on the real-time temperature of the coolant and the target temperature of the coolant. Based on the initial control parameters and the temperature deviation, a proportional-integral-derivative control algorithm is used to calculate the feedback flow correction, and the target flow rate of the coolant is determined based on the coolant reference flow rate and the feedback flow correction. Generate flow regulation parameters to make the coolant flow rate reach the target flow rate of the coolant, and determine heat exchange control parameters according to the cooling mode, and generate a cooling regulation command including the flow regulation parameters and the heat exchange control parameters; The cooling adjustment command is sent to the execution and regulation layer, so that the execution and regulation layer adjusts the coolant flow rate according to the flow rate adjustment parameter, and controls the heat exchanger to exchange heat with the coolant according to the heat exchange control parameter, so as to regulate the coolant temperature.

[0009] The beneficial effects of this invention are as follows: This invention, through an axially extending main cooling channel within the rotor shaft, utilizes a first and second diversion channel to introduce coolant from the main cooling channel into the upper and lower cooling chambers respectively. This allows the coolant, after flowing through the upper bearing chamber, to cool the upper and lower ends of the motor rotor, the upper and lower ends of the stator windings, and the upper and lower inner walls of the motor housing. The coolant continuing to flow along the main cooling channel after diversion can also cool the lower bearing chamber, thereby expanding the cooling coverage of the internal liquid cooling structure of the motor. This achieves coordinated heat dissipation of the rotor ends, stator winding ends, upper and lower bearings, and the motor housing, reducing localized cooling blind spots and heat accumulation. Furthermore, the integration of the main cooling channel and diversion channel into the rotor shaft, with each cooling chamber located within the motor housing, enhances the integration of the liquid cooling structure with the top-drive motor body. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of the overall structure of common top-drive direct-drive motors and permanent magnet motors. Figure 2 This is a schematic diagram of the internal structure of a top-drive direct-drive motor and a permanent magnet motor; Figure 3 This is a schematic diagram of the coolant circulation structure of a top-drive liquid-cooled motor; Figure 4 This is a schematic diagram of the internal coolant flow channels of a top-drive liquid-cooled motor; Figure 5 This is a schematic diagram of the liquid cooling system for the top drive motor; Figure 6 This is a flowchart of the feedback control method for the top drive motor liquid cooling system according to an embodiment of the present invention.

[0011] Figure label: 01. Low-temperature coolant tank; 02. Upper cooling chamber; 03. Lower cooling chamber; 04. Lower bearing chamber; 05. High-temperature coolant tank; 06. Lower coolant tank; 07. Circulating pump; 08. Compressor; 09. Filter; 10. Data acquisition layer; 11. Throttling valve; 12. Condenser; 13. Multi-way reversing valve; 14. Heat exchanger; 20. Intelligent control and decision-making layer; 30. Execution and regulation layer; 100. Fan assembly; 200. Upper bearing chamber; 300. Junction box assembly; 400. Motor rotor assembly; 410. Rotor shaft; 420. Motor rotor; 500. Motor stator assembly; 510. Motor stator; 600. Lower bearing chamber; 700. Motor housing. Detailed Implementation

[0012] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0013] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0014] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification, claims and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products or devices.

[0015] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0016] The purpose of this invention is to provide a top-drive liquid-cooled motor, a top-drive motor liquid cooling system, and a feedback control method. By setting a coordinated cooling path for the motor stator, motor rotor, and upper and lower bearings, and combining it with a feedback control method adapted to the top-drive operating conditions, the cooling coverage range inside the top-drive motor is expanded. This allows the coolant flow rate and heat exchange state to be adjusted according to the top-drive operating conditions and system state, thereby alleviating the problems of traditional air-cooling solutions being susceptible to environmental conditions and prone to loosening of connection structures, as well as the insufficient cooling coverage and low integration degree of existing liquid-cooling solutions with the top-drive device. This improves the controllability and operational reliability of the top-drive motor cooling process.

[0017] Figure 1 The schematic diagram illustrates the overall structure of common top-drive direct-drive motors and permanent magnet motors, such as... Figure 1 As shown, a common top-drive motor may include a fan assembly 100, an upper bearing housing 200, a junction box assembly 300, a motor rotor assembly 400, a motor stator assembly 500, and a lower bearing housing 600. The fan assembly 100 is typically located at the top of the motor and is used for forced air cooling. The upper bearing housing 200 and lower bearing housing 600 are located at the top and bottom of the motor, respectively, and are used to house the bearings supporting the rotor shaft. The junction box assembly 300 is used to establish electrical connection between the motor and external power supply equipment. The motor rotor assembly 400 and the motor stator assembly 500 constitute the main electromagnetic conversion structure of the motor. This invention can improve the internal cooling structure of the motor based on the above basic structure to expand the cooling coverage of the coolant on the heat-generating parts inside the motor.

[0018] In one aspect, the present invention provides a top-drive liquid-cooled motor. In one embodiment of the present invention, the top-drive liquid-cooled motor includes: a motor housing, a motor stator and a motor rotor disposed within the motor housing, a rotor shaft passing through the motor rotor and extending in a vertical direction, and an upper bearing chamber and a lower bearing chamber respectively disposed at the upper and lower ends of the rotor shaft. The motor stator includes a stator core and stator windings disposed on the stator core. The motor housing is provided with an upper cooling chamber and a lower cooling chamber. The upper end of the top-drive liquid-cooled motor is provided with a coolant inlet that communicates with the upper bearing chamber, and the lower end of the top-drive liquid-cooled motor is provided with a coolant outlet. The rotor shaft is a hollow structure, and a main cooling channel extending axially along the rotor shaft is formed inside the rotor shaft. The upper bearing chamber is connected to the upper end of the main cooling channel so that the coolant entering from the coolant inlet flows through the upper bearing chamber and then enters the main cooling channel. The rotor shaft is provided with a first flow divider channel and a second flow divider channel at different axial positions. The first flow divider channel and the second flow divider channel extend from the main cooling channel to the outer periphery of the rotor shaft. The first flow divider channel is connected to the upper cooling chamber, and the second flow divider channel is connected to the lower cooling chamber. The upper cooling chamber is provided corresponding to the upper end of the motor rotor and the upper end of the stator winding, so that the coolant flowing in through the first diversion channel cools the upper end of the motor rotor, the upper end of the stator winding, and the upper inner wall of the motor housing; the lower cooling chamber is provided corresponding to the lower end of the motor rotor and the lower end of the stator winding, so that the coolant flowing in through the second diversion channel cools the lower end of the motor rotor, the lower end of the stator winding, and the lower inner wall of the motor housing. The lower end of the main cooling channel is connected to the lower bearing chamber so that the coolant that continues to flow along the main cooling channel after being diverted by the first diversion channel and the second diversion channel enters the lower bearing chamber. The coolant flowing through the upper cooling chamber, the lower cooling chamber, and the lower bearing chamber is collected at the lower end of the top-drive liquid-cooled motor and discharged through the coolant outlet.

[0019] like Figure 2 , Figure 3 and Figure 4 As shown, the motor housing 700 extends vertically, the motor stator 510 is fixedly installed inside the motor housing 700, and the motor rotor 420 is located radially inside the motor stator 510. The rotor shaft 410 passes through the motor rotor 420 and is fixedly connected to the motor rotor 420. The vertical direction can be determined based on the installation direction of the top-drive liquid-cooled motor in the top-drive device. In one specific implementation, the top-drive liquid-cooled motor is installed vertically, with the upper end of the motor corresponding to the non-drive end and the lower end corresponding to the drive end.

[0020] The upper bearing housing 200 is located axially above the motor rotor 420 and the motor stator 510, and surrounds the upper end of the rotor shaft 410. The upper bearing housing 200 can be formed by the motor upper end cover, the upper bearing seat and the outer peripheral surface of the rotor shaft 410. The upper bearing housing 200 is provided with an upper bearing for supporting the upper end of the rotor shaft 410.

[0021] The lower bearing housing 04 is located axially below the motor rotor 420 and the motor stator 510, and surrounds the lower end of the rotor shaft 410. In one specific implementation, the lower bearing housing 04 can be formed by the space within the lower bearing housing 600 for accommodating the lower bearing and through which coolant flows, or it can be defined by the lower end cover of the motor, the lower bearing housing, and the outer peripheral surface of the rotor shaft 410. Figure 1 and Figure 2 The lower bearing chamber 600 in the text indicates the bearing mounting structure at the bottom of the motor. Figure 3 The lower bearing chamber 04 in the text represents the space in the bearing mounting structure through which coolant flows and cools the lower bearing.

[0022] The upper cooling chamber 02 is located at the axial upper end of the motor rotor 420 and the motor stator 510, and is situated on the axial lower side of the upper bearing chamber 200 and the radial outer side of the rotor shaft 410. In one specific implementation, the upper cooling chamber 02 can be an annular cooling space defined by the upper end of the motor rotor 420, the upper end of the stator winding, the upper inner wall of the motor housing 700, and the upper end cover of the motor.

[0023] The lower cooling chamber 03 is located at the lower axial end of the motor rotor 420 and the motor stator 510, and is situated on the upper axial side of the lower bearing chamber 04 and the radial outer side of the rotor shaft 410. In one specific implementation, the lower cooling chamber 03 can be an annular cooling space defined by the lower end of the motor rotor 420, the lower end of the stator winding, the lower inner wall of the motor housing 700, and the lower end cover of the motor.

[0024] Therefore, the upper bearing chamber 200 and the upper cooling chamber 02 correspond to different cooling targets. The upper bearing chamber 200 is mainly used to house and cool the upper bearing, while the upper cooling chamber 02 is mainly used to cool the upper end of the motor rotor 420, the upper end of the stator winding, and the upper inner wall of the motor housing 700. Correspondingly, the lower bearing chamber 04 is mainly used to house and cool the lower bearing, while the lower cooling chamber 03 is mainly used to cool the lower end of the motor rotor 420, the lower end of the stator winding, and the lower inner wall of the motor housing 700.

[0025] The upper cooling chamber 02 and the lower cooling chamber 03 can be cooling cavities that allow coolant to flow through the corresponding areas of the objects being cooled. The coolant can directly contact the ends of the motor rotor 420, the ends of the stator windings, and the inner wall of the motor housing 700, or it can exchange heat with the aforementioned objects through adjacent heat-conducting structures. When the coolant directly contacts the stator windings or other electrical structures, an insulating coolant compatible with the motor's insulation structure can be used, and the stator windings and corresponding electrical connection points can be insulated and sealed.

[0026] The coolant inlet can be located on the upper end cover of the motor or on the upper bearing housing, and is connected to the inlet side of the upper bearing chamber 200. The upper end of the rotor shaft 410 has a shaft end opening that communicates with the main cooling channel, and the outlet side of the upper bearing chamber 200 is connected to this shaft end opening via a guide cavity or guide channel. Thus, the coolant entering from the coolant inlet flows through the upper bearing and can then enter the main cooling channel through the shaft end opening of the rotor shaft 410.

[0027] A sealing structure adapted to the rotational state of the rotor shaft 410 can be provided between the upper bearing chamber 200 and the rotor shaft 410 to reduce coolant leakage from unintended locations and to ensure that the coolant flows in the order of the upper bearing chamber 200 and the main cooling channel. This sealing structure can be a sealing structure suitable for liquid sealing of rotating shafts, and its specific form can be determined according to the rotational speed of the rotor shaft 410, the coolant pressure, and the type of coolant.

[0028] The first and second diversion channels are respectively located at different axial positions on the rotor shaft 410. The outlet of the first diversion channel is located in the axial region corresponding to the upper cooling chamber 02, allowing some of the coolant in the main cooling channel to flow out from the inside of the rotor shaft 410 to its outer periphery and enter the upper cooling chamber 02. The outlet of the second diversion channel is located in the axial region corresponding to the lower cooling chamber 03, allowing another portion of the coolant in the main cooling channel to enter the lower cooling chamber 03.

[0029] Since both the upper cooling chamber 02 and the lower cooling chamber 03 can be annular spaces surrounding the rotor shaft 410, the first and second diversion channels can continuously supply coolant to the corresponding cooling chambers during the rotation of the rotor shaft 410. The number, diameter, extension direction, and axial position of the first and second diversion channels can be determined based on the heat generation of each cooling object, the required coolant flow rate, and the flow resistance of the corresponding channels.

[0030] After entering the upper cooling chamber 02 through the first branch channel, the coolant can flow along the upper end of the motor rotor 420, the upper end of the stator winding, and the upper inner wall of the motor housing 700, dissipating heat from these areas through contact heat exchange or scouring heat exchange. After entering the lower cooling chamber 03 through the second branch channel, the coolant can flow along the lower end of the motor rotor 420, the lower end of the stator winding, and the lower inner wall of the motor housing 700.

[0031] To allow the coolant in the upper cooling chamber 02 to collect at the lower end of the motor, an axial return channel can be provided within the motor housing 700. This axial return channel can be formed within the wall of the motor housing 700, or between the motor housing 700 and the motor stator 510, connecting the upper cooling chamber 02 and the convergence space at the lower end of the motor. After heat exchange, the coolant in the upper cooling chamber 02 flows downwards through the axial return channel. The outlet side of the lower cooling chamber 03 can be directly connected to this convergence space.

[0032] The lower end of the main cooling channel can be connected to the lower bearing chamber 04 through a shaft end opening located at the lower end of the rotor shaft 410. The coolant, after being diverted by the first and second diversion channels, continues to flow downwards along the main cooling channel, entering the lower bearing chamber 04 through this shaft end opening and flowing through the lower bearing. The outlet side of the lower bearing chamber 04, the outlet side of the lower cooling chamber 03, and the lower end of the axial return channel can all be connected to the confluence space at the lower end of the motor, which in turn connects to the coolant outlet.

[0033] Therefore, as Figure 4 As shown by the arrows, the complete flow path of the coolant can be as follows: the coolant enters the upper bearing chamber 200 from the coolant inlet at the top of the motor, flows through the upper bearing, and then enters the main cooling channel inside the rotor shaft 410; part of the coolant in the main cooling channel enters the upper cooling chamber 02 through the first branch channel, part of the coolant enters the lower cooling chamber 03 through the second branch channel, and the remaining coolant enters the lower bearing chamber 04 along the main cooling channel; the coolant in the upper cooling chamber 02 flows to the lower end of the motor through the axial return channel, and merges with the coolant flowing out of the lower cooling chamber 03 and the lower bearing chamber 04, and finally is discharged to the lower coolant tank 06 through the coolant outlet.

[0034] When an oil-based coolant is used, the coolant can also lubricate the upper and lower bearings as it flows through the upper bearing chamber 200 and the lower bearing chamber 04, thus combining the bearing cooling function with the bearing lubrication function, reducing or eliminating the need for additional grease injection into the bearings.

[0035] Through the above cooling path, the coolant can simultaneously reach the upper and lower ends of the motor rotor 420, the upper and lower ends of the stator winding, the upper and lower end bearings, and the corresponding inner walls of the motor housing 700, thereby expanding the cooling coverage of the internal liquid cooling structure of the motor and reducing the cooling blind spots at the rotor ends and bearings that may be formed when only the motor housing 700 or the motor stator 510 is cooled.

[0036] In one embodiment of the present invention, the stator core is formed by stacking multiple stator laminations, each of which is provided with a circumferential liquid passage. The multiple stator laminations are stacked in a staggered manner so that the multiple circumferential liquid passages are connected in sequence, forming a continuous three-dimensional meandering cooling channel in the stator core. The stator core has grooves on its outside, and the motor housing has a housing flow channel that matches the grooves. The housing flow channel and the three-dimensional meandering cooling channel together constitute the cooling flow path of the motor stator.

[0037] In one specific implementation, the stator laminations can be made of silicon steel sheets. Circumferential cooling channels can be formed on the outer periphery of the stator laminations and extend circumferentially. When multiple stator laminations are stacked, adjacent stator laminations are staggered at predetermined angles or positions, so that the circumferential cooling channels on adjacent stator laminations are sequentially connected in the axial and circumferential directions, thereby forming a three-dimensional meandering cooling channel that can extend in different directions inside the stator core.

[0038] The grooves on the outside of the stator core can extend along the axial, circumferential, or helical direction of the stator core. The housing flow channels can be integrally cast during the manufacturing process of the motor housing 700, or they can be formed by machining. The motor housing 700 can be provided with flow channel inlets and flow channel outlets that communicate with the three-dimensional meandering cooling channel and the housing flow channels respectively, so that the three-dimensional meandering cooling channel and the housing flow channels form a continuous stator cooling flow path.

[0039] In one implementation, the inlet of the stator cooling flow path can be connected to the upper cooling chamber 02, and its outlet can be connected to the lower cooling chamber 03 or the confluence space at the lower end of the motor. A portion of the coolant entering the upper cooling chamber 02 through the first branch channel can enter the stator cooling flow path, flowing sequentially through the three-dimensional meandering cooling channel inside the stator core and the casing flow channel inside the motor housing 700 before flowing towards the lower end of the motor. The stator cooling flow path can also be connected to the coolant circulation path inside the motor as a cooling branch parallel to the main cooling flow path.

[0040] The three-dimensional meandering cooling channels allow coolant to enter the stator core and increase the heat exchange path between the coolant and the stator core; the casing flow channels can remove the heat transferred from the stator core to the motor housing 700. Together, these features allow for simultaneous cooling of both the internal and external areas of the stator core.

[0041] In one embodiment of the present invention, the top-drive liquid-cooled motor is an asynchronous motor, and the motor rotor includes a rotor core, rotor bars disposed in the rotor core, and rotor end rings respectively disposed at both ends of the rotor bars; The first diversion channel includes a plurality of radial oblique holes disposed on the rotor shaft and located below the upper bearing chamber. The plurality of radial oblique holes are evenly distributed along the circumference of the rotor shaft and connect the main cooling channel with the upper cooling chamber. The second diversion channel includes a plurality of radial holes disposed on the rotor shaft and corresponding to the lower end of the rotor core, and the plurality of radial holes connect the main cooling channel and the lower cooling chamber; At least one location in the region where the rotor guide bar is located and the region where the rotor end ring is located is provided with a composite phase change material for absorbing transient heat.

[0042] In one specific implementation, the rotor shaft 410 is forged from high-strength alloy steel, and the central through hole of the rotor shaft 410 constitutes the main cooling channel. The number of radial oblique holes can be no less than three, and these radial oblique holes are evenly distributed along the circumference of the rotor shaft 410. The inclination direction and angle of the radial oblique holes can be determined based on the rotation direction and speed of the rotor shaft 410 and the required coolant flow rate of the upper cooling chamber 02.

[0043] Multiple radial holes in the second diversion channel can be located at the axial position corresponding to the lower end of the rotor core and distributed circumferentially along the rotor shaft 410. After the coolant enters the lower cooling chamber 03 through these radial holes, it can flow to the lower end of the rotor end ring and the lower end of the stator winding.

[0044] The shape of the rotor end ring can be set according to the coolant flow direction to increase the heat exchange contact area between the rotor end ring and the coolant. This heat exchange contact area can be achieved by appropriately enlarging the surface of the rotor end ring that can contact the coolant, but a specific rotor end ring shape is not required.

[0045] The composite phase change material can be placed near the rotor bars, near the rotor end rings, or in the heat-concentrated areas between them. It can be housed within the motor rotor 420 via a receiving groove, encapsulation structure, or fixing structure to prevent the composite phase change material from falling off or shifting during rotor rotation. The composite phase change material absorbs transient heat during transient overloads or sudden load changes in the motor, buffering rapid temperature changes in the rotor bars and rotor end rings and reducing thermal stress caused by repeated thermal shocks.

[0046] In one specific application, the top drive unit can be used for onshore or offshore drilling operations at a drilling depth of approximately 7000 meters and can be equipped with two three-phase asynchronous motors operating in parallel. Each asynchronous motor can have a rated power of 375kW and a rated current of 495A. These application parameters are merely one implementation example and do not constitute a limitation on the number, power, or rated current of the top drive liquid-cooled motors.

[0047] In one embodiment of the present invention, the top-drive liquid-cooled motor is a permanent magnet synchronous motor, and the motor rotor includes a rotor core and permanent magnets disposed in permanent magnet slots in the rotor core; The rotor core is provided with multiple sets of permanent magnet cooling channels extending axially along the rotor shaft. The permanent magnet cooling channels are arranged parallel to the permanent magnet slots and extend along the back of the corresponding permanent magnets. The multiple sets of permanent magnet cooling channels are respectively connected to the main cooling channel through radial branch pipes, so that the coolant in the main cooling channel enters the permanent magnet cooling channel through the radial branch pipes and flows along the back of the corresponding permanent magnet; The permanent magnet has a composite phase change material in the interpole gap for absorbing transient heat.

[0048] In one specific implementation, the rotor shaft 410 of the permanent magnet synchronous motor can be forged from high-strength non-magnetic alloy steel, with its central through hole forming the main cooling channel. The permanent magnet cooling channel extends along the axial length of the permanent magnet and is located on the side of the permanent magnet facing away from the motor air gap, in order to shorten the heat transfer distance between the permanent magnet and the coolant.

[0049] Radial branch pipes can extend radially outward from the main cooling channel to the rotor core and connect to the inlets of each group of permanent magnet cooling channels. In one specific implementation, the lower axial end of the permanent magnet cooling channel is connected to the lower cooling chamber 03. Coolant enters the permanent magnet cooling channel from the main cooling channel through the radial branch pipes, flows downward along the back of the permanent magnet, completes heat exchange, and then enters the lower cooling chamber 03, where it merges with other coolant in the lower cooling chamber 03.

[0050] Each set of permanent magnet cooling channels can be set up separately for one set of permanent magnets, or one set of permanent magnet cooling channels can simultaneously correspond to multiple permanent magnets arranged circumferentially. The number, cross-sectional area, and circumferential distribution of permanent magnet cooling channels can be determined based on the number of permanent magnets, loss distribution, and required coolant flow rate.

[0051] Composite phase change materials can be filled into the interpole gaps between adjacent magnetic poles and held in place by encapsulation or fixing structures. The active liquid cooling structure formed by the permanent magnet cooling channels continuously removes the heat generated by the permanent magnet, while the composite phase change material absorbs transient heat generated in a short period during motor transient overloads. Together, they buffer rapid temperature changes in the permanent magnet.

[0052] In one specific application, the top drive unit can be used for direct-drive top drive operations on land or at sea at drilling depths of approximately 7000 meters, and can be equipped with a built-in permanent magnet synchronous motor with a rated power of 735kW and a rated current of 850A. This permanent magnet synchronous motor can directly drive the corresponding drilling structure without a gearbox. The above application parameters are only one implementation example and do not constitute a limitation on the power, current, or transmission form of the permanent magnet synchronous motor.

[0053] In one embodiment of the present invention, the motor housing is provided with an inner cooling channel and an outer cooling channel located outside the inner cooling channel. The inner cooling channel is arranged along the outer peripheral surface of the stator core and is in contact with the outer peripheral surface of the stator core. The outer cooling channel is used for the circulation of coolant.

[0054] The inner cooling channels can be arranged continuously or at intervals along the outer circumferential surface of the stator core and are in contact with at least a portion of the outer circumferential surface of the stator core to shorten the heat transfer path between the stator core and the cooling structure. The outer cooling channels are located radially outside the inner cooling channels and can extend along the circumferential, axial or helical direction of the motor housing 700.

[0055] In one specific implementation, the inner and outer cooling channels can be connected in series or in parallel through a connecting channel within the motor housing 700. The coolant can circulate through the outer cooling channel, carrying away heat transferred from the stator core to the motor housing 700 via the area containing the inner cooling channel. The inner cooling channel can also connect with the three-dimensional meandering cooling channel inside the stator core, allowing for coordinated cooling of the stator core's interior, the stator core's exterior, and the motor housing 700.

[0056] For permanent magnet synchronous motors, the cross-sectional area, extension path, and coolant flow rate of the three-dimensional meandering cooling channel, inner cooling channel, and outer cooling channel can be adjusted according to the actual heat load of the motor to match the cooling capacity of the motor stator 510 and the motor rotor 420 with the corresponding heat generation.

[0057] In another aspect, the present invention provides a top drive motor liquid cooling system. In one embodiment of the present invention, the top drive motor liquid cooling system includes: a top drive liquid-cooled motor as described in any of the above embodiments, a coolant circulation loop, a data acquisition layer, an intelligent control and decision-making layer, and an execution and regulation layer; The coolant circulation loop includes a low-temperature coolant tank, a lower coolant tank, a high-temperature coolant tank, a circulation pump, a heat exchanger, a filter, and connecting pipes. The low-temperature coolant tank is connected to the coolant inlet of the top-drive liquid-cooled motor, the coolant outlet of the top-drive liquid-cooled motor is connected to the lower coolant tank, the lower coolant tank is connected to the high-temperature coolant tank, and the high-temperature coolant tank is connected to the low-temperature coolant tank via the heat exchanger and the filter, thereby forming a closed loop. The circulation pump is installed in the coolant circulation loop to drive the coolant circulation. The data acquisition layer is used to acquire motor status data of the top-drive liquid-cooled motor and loop status data of the coolant circulation loop, and to receive top-drive operating condition signals. The motor status data includes stator winding temperature data, upper bearing temperature data, and lower bearing temperature data. The loop status data includes coolant temperature data at the coolant inlet and outlet, pressure data and flow data in the coolant circulation loop, and liquid level data of the low-temperature coolant tank and the high-temperature coolant tank. The intelligent control and decision-making layer is communicatively connected to the data acquisition layer and the execution and regulation layer, respectively, and is used to generate cooling regulation commands based on the motor status data, the circuit status data and the top drive condition signal; The execution and regulation layer includes a flow and direction control unit and a power and heat exchange unit. The flow and direction control unit is located in the coolant circulation loop and is used to adjust the flow rate and flow path of the coolant according to the cooling regulation command. The power and heat exchange unit includes the circulation pump and the heat exchanger and is used to control the operation of the circulation pump according to the cooling regulation command and to regulate the coolant temperature through the heat exchanger.

[0058] like Figure 3 and Figure 5 As shown, the top drive motor liquid cooling system of this embodiment of the invention uses the top drive liquid-cooled motor as the cooling object. Coolant that has been cooled is continuously supplied to the top drive liquid-cooled motor through a coolant circulation loop. A closed-loop control structure from state perception and control decision to command execution is formed through the data acquisition layer 10, the intelligent control and decision layer 20 and the execution and regulation layer 30.

[0059] The aforementioned top-drive liquid-cooled motor can be an asynchronous motor or a permanent magnet synchronous motor as described in any of the preceding embodiments. The upper bearing chamber 200, main cooling channel, upper cooling chamber 02, lower cooling chamber 03, and lower bearing chamber 04 within the top-drive liquid-cooled motor constitute the internal cooling path of the motor. The low-temperature coolant tank 01, lower coolant tank 06, high-temperature coolant tank 05, circulating pump 07, heat exchanger 14, filter 09, and connecting pipes constitute the coolant circulation loop located outside the motor. The coolant inlet and coolant outlet of the top-drive liquid-cooled motor form the connection point between the internal cooling path of the motor and the external coolant circulation loop.

[0060] The cryogenic coolant tank 01 is used to store cryogenic coolant after heat exchange and filtration, and to supply coolant to the top-drive liquid-cooled motor. Here, "cryogenic coolant" refers to coolant with a lower temperature relative to the coolant discharged from the top-drive liquid-cooled motor; it is not required that the coolant in the cryogenic coolant tank 01 be below a specific absolute temperature. The volume of the cryogenic coolant tank 01 can be determined based on the required coolant flow rate and coolant circulation cycle of the top-drive liquid-cooled motor.

[0061] The cryogenic coolant tank 01 is connected to the coolant inlet of the top-drive liquid-cooled motor via a connecting pipe. A circulation pump 07 can be installed between the cryogenic coolant tank 01 and the coolant inlet, so that the circulation pump 07 delivers the coolant in the cryogenic coolant tank 01 to the top-drive liquid-cooled motor. After the coolant enters the top-drive liquid-cooled motor, it cools the upper bearing, the upper and lower ends of the motor rotor 420, the upper and lower ends of the stator windings, the motor housing 700, and the lower bearing according to the aforementioned internal cooling path of the motor.

[0062] The lower coolant tank 06 is located downstream of the coolant outlet of the top-drive liquid-cooled motor and is connected to the coolant outlet via a connecting pipe. It is used to receive and collect the coolant discharged from the lower end of the top-drive liquid-cooled motor. Since the coolant flowing out of the top-drive liquid-cooled motor has absorbed the heat generated by the various heat-generating parts inside the motor, its temperature is usually higher than the coolant temperature in the low-temperature coolant tank 01.

[0063] The lower coolant tank 06 can be located near the lower end of the top-drive liquid-cooled motor to shorten the drain path of the top-drive liquid-cooled motor and provide a collection and buffer space for the coolant flowing out from the upper cooling chamber 02, the lower cooling chamber 03, and the lower bearing chamber 04. When the top drive unit includes multiple top-drive liquid-cooled motors, the coolant outlets of the multiple top-drive liquid-cooled motors can be connected to the lower coolant tank 06, which centrally receives the coolant discharged from each top-drive liquid-cooled motor.

[0064] The high-temperature coolant tank 05 is located downstream of and connected to the lower coolant tank 06. The high-temperature coolant tank 05 receives the coolant supplied from the lower coolant tank 06 and provides coolant to be cooled to the heat exchanger 14. Here, "high-temperature coolant" refers to coolant that has not yet undergone cooling treatment by the heat exchanger 14 and has a higher temperature than the coolant in the low-temperature coolant tank 01; it is not required to reach a specific absolute temperature.

[0065] The lower coolant tank 06 is mainly used to collect the coolant discharged from the top-drive liquid-cooled motor, while the high-temperature coolant tank 05 is mainly used to store and buffer the coolant to be exchanged upstream of the heat exchanger 14. By setting the lower coolant tank 06 and the high-temperature coolant tank 05 separately, the function of collecting the coolant at the lower end of the motor can be separated from the function of storing and supplying the coolant upstream of the heat exchanger 14, and the instantaneous flow rate changes caused by changes in the operating conditions of the top drive can be buffered.

[0066] The circulating pump 07 is installed in the coolant circulation loop to establish the pressure and flow rate required for coolant flow within the loop. The circulating pump 07 can be installed between the low-temperature coolant tank 01 and the coolant inlet of the top-drive liquid-cooled motor, or between the lower coolant tank 06 and the high-temperature coolant tank 05, or at other suitable locations within the coolant circulation loop.

[0067] like Figure 3As shown, in one specific implementation, two circulation pumps 07 can be installed in the coolant circulation loop. One circulation pump 07 is located between the low-temperature coolant tank 01 and the top-drive liquid-cooled motor, used to deliver the low-temperature coolant to the top-drive liquid-cooled motor; the other circulation pump 07 is located between the lower coolant tank 06 and the high-temperature coolant tank 05, used to deliver the coolant in the lower coolant tank 06 to the high-temperature coolant tank 05. In another implementation, only one circulation pump 07 can be installed, which drives the coolant to circulate throughout the entire coolant circulation loop.

[0068] Heat exchanger 14 is located downstream of high-temperature coolant tank 05 and is used to exchange heat between the coolant flowing through heat exchanger 14 and the heat exchange medium, thereby removing the heat absorbed by the coolant in the top-drive liquid-cooled motor. The heat exchanger 14 can be configured with appropriate heat exchange area and capacity based on the heat output of the top-drive liquid-cooled motor, the target temperature of the coolant, and the ambient operating temperature. The heat exchange medium and its circulation structure will be further described in subsequent embodiments.

[0069] Filter 09 is located between heat exchanger 14 and cryogenic coolant tank 01 to filter particulate matter or other impurities carried during coolant circulation, reducing the deposition or blockage of impurities in the main cooling channel, first branch channel, second branch channel, three-dimensional bypass cooling channel, and other cooling channels. After heat exchange and filtration, the coolant flows back to cryogenic coolant tank 01 for the next cycle. When using oil-based coolant, filter 09 can also filter wear particles and other contaminants from the oil-based coolant.

[0070] In one specific implementation, the circulating flow path of the coolant is as follows: low-temperature coolant tank 01, circulating pump 07, coolant inlet of top-drive liquid-cooled motor, cooling path inside top-drive liquid-cooled motor, coolant outlet of top-drive liquid-cooled motor, lower coolant tank 06, high-temperature coolant tank 05, heat exchanger 14, filter 09, and low-temperature coolant tank 01.

[0071] The term "closed-loop circulation" here refers to the coolant circulating between the top-drive liquid-cooled motor and the coolant circulation loop, rather than being directly discharged to the outside of the system after each cooling cycle. Closed-loop circulation does not require each coolant tank in the circulation loop to be a completely sealed pressure vessel. The system can be configured with a coolant replenishment structure based on coolant loss, but during normal cooling, the coolant primarily circulates within the aforementioned cooling path.

[0072] The connecting pipeline is used to achieve fluid communication between the cryogenic coolant tank 01, the top-drive liquid-cooled motor, the lower coolant tank 06, the high-temperature coolant tank 05, the circulating pump 07, the heat exchanger 14, and the filter 09. The diameter, length, and arrangement of the connecting pipeline can be determined based on the target coolant flow rate, system pressure loss, and the installation space inside the top drive unit.

[0073] like Figure 5 As shown, the top drive motor liquid cooling system can be functionally divided into a data acquisition layer 10, an intelligent control and decision-making layer 20, and an execution and regulation layer 30. These three layers represent the logical relationships between different functional units within the top drive motor liquid cooling system, and do not require each layer to be set as an independent physical device. The same control device can implement the corresponding functions of one or more layers.

[0074] The data acquisition layer 10 is used to acquire data that reflects the current operating status of the top-drive liquid-cooled motor and the coolant circulation loop. The data acquisition layer 10 can continuously acquire data or acquire corresponding data according to a predetermined sampling period, and send the acquired motor status data, loop status data and received top-drive operating condition signals to the intelligent control and decision layer 20.

[0075] Motor status data is used to characterize the temperature status of the main heat-generating components inside the top-drive liquid-cooled motor, including stator winding temperature data, upper bearing temperature data, and lower bearing temperature data. Stator winding temperature data can be used to determine the thermal load and insulation temperature status of the motor stator 510; upper and lower bearing temperature data can be used to determine the heat generation of the upper and lower bearings and whether the coolant flowing through the corresponding bearing chambers meets the bearing cooling requirements.

[0076] The loop status data is used to characterize the operating status of the coolant circulation loop, including coolant temperature data at the coolant inlet and outlet, pressure and flow data in the coolant circulation loop, and liquid level data of the low-temperature coolant tank 01 and the high-temperature coolant tank 05.

[0077] The temperature data at the coolant inlet characterizes the temperature of the coolant entering the top-drive liquid-cooled motor, while the temperature data at the coolant outlet characterizes the temperature of the coolant after heat exchange within the motor. These temperature data can be used individually or in combination to reflect the temperature change of the coolant before and after flowing through the top-drive liquid-cooled motor.

[0078] Pressure data can be used to characterize the operation of the circulating pump 07 and to determine if there is insufficient pressure, abnormal pressure rise, or increased flow resistance in the coolant circulation loop. Flow data can be used to characterize the flow rate of coolant flowing into the top-drive liquid-cooled motor or through the coolant circulation loop, and can serve as feedback data for adjusting the circulating pump 07 and flow control components.

[0079] The liquid level data of the low-temperature coolant tank 01 and the high-temperature coolant tank 05 can be used to determine whether the coolant level meets the system circulation requirements and to identify situations such as insufficient coolant or abnormal changes in liquid level. The data acquisition layer 10 can acquire the above data through temperature detection devices, pressure detection devices, flow detection devices, and liquid level detection devices set at corresponding detection locations. The specific detection devices and their locations will be further described in subsequent embodiments.

[0080] The top drive operating condition signal is used to characterize the current drilling operation status or motor load status of the top drive unit. The top drive operating condition signal can be provided by the top drive main control system or the driller's rig, and sent to the data acquisition layer 10 through the corresponding top drive operating condition signal interface. The data acquisition layer 10 sends the top drive operating condition signal, along with the acquired motor status data and loop status data, to the intelligent control and decision layer 20, so that the intelligent control and decision layer 20 can determine the current and potential cooling requirements of the top drive liquid-cooled motor.

[0081] The intelligent control and decision-making layer 20 is communicatively connected to the data acquisition layer 10 and the execution and regulation layer 30, respectively. This communication connection can employ wired communication, fieldbus, fiber optic communication, or other communication methods suitable for the drilling environment. The intelligent control and decision-making layer 20 receives motor status data, circuit status data, and top drive operating condition signals sent by the data acquisition layer 10, and determines the cooling requirements of the top drive liquid-cooled motor based on this data and signals.

[0082] The intelligent control and decision-making layer 20 can determine whether to increase or decrease the coolant flow rate based on the stator winding temperature, the upper and lower bearing temperatures, and the coolant inlet and outlet temperatures. It can also determine whether the coolant circulation loop is operating according to a predetermined state based on the loop pressure, loop flow rate, and coolant tank level. The intelligent control and decision-making layer 20 can also combine the top drive operating condition signal to adjust the operating state of the cooling system in advance or synchronously when the top drive load changes.

[0083] Cooling regulation commands may include at least one of the following: coolant flow rate regulation command, flow path switching command, circulating pump operation regulation command, and heat exchange regulation command. The intelligent control and decision layer 20 sends the cooling regulation commands to the execution and regulation layer 30, which then controls the corresponding execution components to perform their actions.

[0084] The execution and regulation layer 30 is used to receive and execute cooling regulation commands generated by the intelligent control and decision layer 20, including flow and direction control units and power and heat exchange units.

[0085] The flow and direction control unit is located in the coolant circulation loop and is used to change the flow area or connectivity of the corresponding flow path according to the cooling adjustment command, thereby adjusting the coolant flow rate of the entire coolant circulation loop or the corresponding branch, and switching between different coolant flow paths. The flow and direction control unit may include valves for adjusting the flow rate and valves for switching the flow path, and their specific composition and connection method will be further described in subsequent embodiments.

[0086] The power and heat exchange unit includes a circulating pump 07 and a heat exchanger 14. The circulating pump 07 starts, stops, or changes its operating state according to cooling regulation commands to adjust the flow rate and pressure of the coolant in the coolant circulation loop.

[0087] The heat exchanger 14 is used to exchange heat between the coolant and the heat exchange medium. The execution and regulation layer 30 can adjust the flow rate or flow path of the coolant through the heat exchanger 14 according to the cooling regulation command, and can also adjust the operating state of the heat exchange medium circulation equipment connected to the heat exchanger 14, thereby changing the heat exchange capacity of the heat exchanger 14 for the coolant and regulating the temperature of the coolant returning to the low-temperature coolant tank 01.

[0088] The data acquisition layer 10, the intelligent control and decision-making layer 20, and the execution and regulation layer 30 together form a closed-loop control process. The data acquisition layer 10 collects the current status of the top drive liquid-cooled motor and the coolant circulation loop, and sends the collected data and top drive operating condition signals to the intelligent control and decision-making layer 20; the intelligent control and decision-making layer 20 generates cooling regulation commands based on the above data and signals; the execution and regulation layer 30 changes the operating status of the circulation pump 07, heat exchanger 14, and corresponding flow and direction control components according to the cooling regulation commands; after the system status changes, the data acquisition layer 10 collects the corresponding status data again and feeds it back to the intelligent control and decision-making layer 20, thereby forming continuous closed-loop regulation.

[0089] Through the above structure, the top drive motor liquid cooling system can combine the multi-part coordinated cooling structure inside the top drive liquid-cooled motor with the external coolant circulation loop, and adjust the coolant flow rate, flow path, and temperature according to the motor status, coolant circulation loop status, and top drive operating conditions. Therefore, the operating state of the cooling system can be adapted to the actual cooling requirements of the top drive device, and the controllability of the cooling process of the top drive liquid-cooled motor can be improved.

[0090] In one embodiment of the present invention, the power and heat exchange unit further includes a refrigerant circulation loop, the refrigerant circulation loop including a compressor, a condenser, a throttle valve and the heat exchanger connected by a refrigerant pipeline, the refrigerant circulation loop being used to cool the coolant in the coolant circulation loop through the heat exchanger; The intelligent control and decision-making layer is also used to determine whether the preset cooling start-up conditions are met based on the motor status data, the circuit status data and the top drive condition signal, and to generate a cooling start-stop command based on the determination result. The power and heat exchange unit is also used to control the compressor to start and stop according to the refrigeration start / stop command.

[0091] like Figure 3 As shown, the refrigerant circulation loop can adopt a vapor compression refrigeration cycle. The refrigerant outlet of compressor 08 is connected to the refrigerant inlet of condenser 12, the refrigerant outlet of condenser 12 is connected to the inlet of throttle valve 11, the outlet of throttle valve 11 is connected to the refrigerant inlet of heat exchanger 14, and the refrigerant outlet of heat exchanger 14 is connected to the refrigerant inlet of compressor 08, thus forming a closed refrigerant circulation path.

[0092] Compressor 08 compresses the low-pressure gaseous refrigerant, transforming it into a high-temperature, high-pressure gaseous refrigerant. This high-temperature, high-pressure gaseous refrigerant enters condenser 12, releasing heat to the external environment or the corresponding cooling medium, and condenses to form a high-pressure liquid refrigerant. The high-pressure liquid refrigerant flows through expansion valve 11, where its pressure and temperature decrease, forming a low-temperature, low-pressure two-phase gas-liquid refrigerant. This low-temperature, low-pressure refrigerant enters heat exchanger 14, absorbs heat from the coolant, and evaporates. The low-pressure gaseous refrigerant, having completed heat absorption, returns to compressor 08 for the next refrigeration cycle.

[0093] The heat exchanger 14 is connected to both the coolant circulation loop and the refrigerant circulation loop. In one specific implementation, the heat exchanger 14 forms a coolant flow space and a refrigerant flow space that are isolated from each other and capable of heat exchange. The coolant in the coolant circulation loop flows through the coolant flow space, and the throttled refrigerant flows through the refrigerant flow space; the two do not mix but exchange heat through the heat exchange walls of the heat exchanger 14. Therefore, the heat exchanger 14 is used to reduce the coolant temperature in the coolant circulation loop and serves as a heat exchange component for the refrigerant to absorb heat and evaporate in the refrigerant circulation loop.

[0094] The preset cooling start-up conditions can be set according to the safe temperature range of the top drive liquid-cooled motor, the target temperature of the coolant, the operating status of the top drive, and the ambient temperature. For example, when the stator winding temperature, the upper bearing temperature, the lower bearing temperature, or the coolant outlet temperature reaches the corresponding preset temperature, it can be determined that the preset cooling start-up conditions are met; when the top drive device enters a heavy-load drilling state, and the motor input power or torque current reaches the corresponding set range, it can also be determined that the preset cooling start-up conditions are met.

[0095] The intelligent control and decision-making layer 20 can make judgments by comprehensively considering motor status data, loop status data, and top drive operating condition signals, rather than controlling the refrigerant circulation loop based solely on a single temperature data point. For example, even if the current motor temperature has not yet reached the corresponding upper temperature limit, when the top drive operating condition signal indicates that the motor is about to enter a continuous heavy load state, a refrigeration start command for starting the compressor 08 can be generated in advance.

[0096] When motor status data, circuit status data, and top drive operating condition signals indicate a decrease in active cooling demand and the corresponding cooling stop conditions are met, the intelligent control and decision layer 20 can generate a cooling stop command to stop the compressor 08. A temperature difference or duration condition can be set between the cooling start and stop conditions to reduce frequent starts and stops of the compressor 08 near critical temperatures.

[0097] Upon receiving a refrigeration start command, the power and heat exchange unit controls the compressor 08 to start, enabling the refrigerant circulation loop to actively cool the coolant through the heat exchanger 14; upon receiving a refrigeration stop command, it controls the compressor 08 to stop. During top-drive light-load operation or standby, when the coolant temperature and motor temperature are within the allowable range, the compressor 08 can be stopped to reduce unnecessary operation of the refrigerant circulation loop.

[0098] In one embodiment of the present invention, the flow and direction control unit includes a proportional regulating valve and a multi-way reversing valve. Both the proportional regulating valve and the multi-way reversing valve are disposed in the coolant circulation loop. The proportional regulating valve is used to regulate the coolant flow according to the cooling regulation command, and the multi-way reversing valve is used to switch between a bypass circulation path through the heat exchanger and a heat exchange circulation path through the heat exchanger according to the cooling regulation command. The power and heat exchange unit also includes a variable frequency drive connected to the circulating pump drive, the variable frequency drive being used to adjust the speed of the circulating pump according to the cooling adjustment command.

[0099] The proportional control valve is installed in the main pipeline or corresponding inlet branch of the coolant circulation loop. The opening degree of the proportional control valve can be continuously adjusted within the corresponding operating range to change the flow area and coolant flow rate of the flow path. The intelligent control and decision layer 20 can generate a corresponding cooling adjustment command based on the difference between the target coolant flow rate and the actual flow rate, and the execution and adjustment layer 30 increases or decreases the opening degree of the proportional control valve according to the cooling adjustment command.

[0100] A multi-way directional valve 13 is installed in the coolant circulation loop to switch the flow path of the coolant. In one specific implementation, a bypass circulation path and a heat exchange circulation path are connected in parallel between the downstream of the high-temperature coolant tank 05 and the upstream of the filter 09. The bypass circulation path bypasses the heat exchanger 14, while the heat exchange circulation path passes through the heat exchanger 14. The multi-way directional valve 13 can be installed at the branching or merging point of the two paths to selectively connect the bypass circulation path or the heat exchange circulation path.

[0101] When the top-drive liquid-cooled motor is in standby or light-load operation, and the coolant temperature is within the allowable range, the multi-way reversing valve 13 can connect the bypass circulation path, allowing the coolant to bypass the heat exchanger 14 and continue flowing in the coolant circulation loop. When the top-drive liquid-cooled motor is under heavy load or the coolant temperature needs to be reduced, the multi-way reversing valve 13 can switch to the heat exchange circulation path, allowing the coolant to flow through the heat exchanger 14 for heat exchange.

[0102] The proportional control valve is a flow regulating component in the coolant circulation loop, while the throttle valve 11 is a refrigerant throttling component in the refrigerant circulation loop. They are located in different loops and have different functions. The proportional control valve is used to regulate the coolant flow rate, while the throttle valve 11 is used to reduce the refrigerant pressure; the two should not be confused.

[0103] The variable frequency drive (VFD) is connected to the circulating pump 07 to provide corresponding drive signals and to change the operating frequency and speed of the circulating pump 07 according to the cooling adjustment command. The VFD and the circulating pump 07 have an electrical drive relationship; the VFD is not a component of the fluid pipeline through which the coolant actually flows.

[0104] By adjusting the speed of the circulating pump 07, the total circulation flow and pressure of the coolant circulation loop can be changed; by adjusting the opening of the proportional control valve, the coolant flow in the corresponding main or branch circuit can be further adjusted; by controlling the multi-way directional valve 13, it is possible to switch whether the coolant flows through the heat exchanger 14. The intelligent control and decision-making layer 20 can coordinate the control of the circulating pump 07, the proportional control valve, and the multi-way directional valve 13 to adapt the coolant flow, flow path, and heat exchange status to the cooling requirements of the top-drive liquid-cooled motor.

[0105] In one embodiment of the present invention, the data acquisition layer includes a temperature sensor group, a pressure sensor group, a flow sensor group, a liquid level sensor group, and a top drive condition signal interface. The temperature sensor group includes multiple temperature sensors respectively corresponding to the stator winding, the bearing in the upper bearing chamber, the bearing in the lower bearing chamber, the coolant inlet, the coolant outlet, and the environment where the top-drive liquid-cooled motor is located, for detecting the stator winding temperature, the upper bearing temperature, the lower bearing temperature, the coolant inlet temperature, the coolant outlet temperature, and the ambient temperature. The pressure sensor group includes multiple pressure sensors respectively installed at the outlet of the circulating pump, the main pipeline of the coolant circulation loop, and the inlet branch connected to the coolant inlet, for detecting the coolant pressure at corresponding locations. The flow sensor group includes multiple flow sensors respectively disposed on the main pipeline and the inlet branch, for detecting the flow rate of coolant in the main pipeline and the inlet branch respectively; The liquid level sensor group includes liquid level sensors respectively disposed in the low-temperature coolant tank and the high-temperature coolant tank, for detecting the coolant level in the low-temperature coolant tank and the high-temperature coolant tank respectively; The top drive operating condition signal interface is communicatively connected to the top drive main control system and is used to receive the top drive operating condition signals sent by the top drive main control system. The top drive operating condition signals include motor speed signals, torque current signals, motor input power signals, and operating condition status signals sent from the driller's platform to the top drive main control system.

[0106] like Figure 5 As shown, the temperature sensor group, pressure sensor group, flow sensor group, liquid level sensor group and top drive operating condition signal interface together constitute the data acquisition layer 10, which is used to obtain the data and signals required for the control of the top drive motor liquid cooling system from the motor body, coolant circulation loop and top drive main control system.

[0107] The temperature sensor group may include multiple temperature sensors disposed at corresponding positions on the three-phase stator windings to detect the temperature of different phase stator windings respectively. The temperature sensors may also be disposed in the upper bearing chamber 200 and the lower bearing chamber 04 respectively, close to the corresponding bearings, to detect the temperature of the upper bearing and the temperature of the lower bearing.

[0108] A temperature sensor corresponding to the coolant inlet is used to detect the temperature of the coolant entering the top-drive liquid-cooled motor, and a temperature sensor corresponding to the coolant outlet is used to detect the coolant temperature after heat exchange within the motor. The intelligent control and decision-making layer 20 can determine the temperature change of the coolant before and after flowing through the top-drive liquid-cooled motor based on the coolant inlet and outlet temperatures.

[0109] The ambient temperature sensor can be placed in a location that reflects the ambient temperature of the top drive liquid-cooled motor and is not easily affected by local heat sources. The ambient temperature data can be used to adjust the cooling control parameters under different well site, season, or ambient temperature conditions.

[0110] In one specific implementation, each top-drive liquid-cooled motor can be equipped with multiple temperature measuring points. In addition to the stator windings, upper and lower bearings, and coolant inlets and outlets, temperature sensors can also be installed in the motor's internal cavities or other locations requiring monitoring of heat generation. The specific number of temperature measuring points can be determined based on the motor's power, structural dimensions, and the required temperature monitoring range.

[0111] The pressure sensor group includes a pressure sensor located at the outlet of circulating pump 07 to detect the coolant pressure output by circulating pump 07; a pressure sensor located on the main coolant circulation loop to detect the system main loop pressure; and a pressure sensor located on the inlet branch of the top drive liquid-cooled motor to detect the coolant pressure entering the corresponding top drive liquid-cooled motor. By comparing the pressure data at different locations, the output status of circulating pump 07 and whether there are any abnormal pressures or increased flow resistance in the corresponding pipelines can be determined.

[0112] The flow sensor group includes flow sensors installed on the main coolant circulation loop and flow sensors installed on the inlet branch. The flow sensors on the main coolant circulation loop are used to detect the total flow rate of the coolant circulation loop, while the flow sensors on the inlet branch are used to detect the flow rate of coolant flowing into the corresponding top-drive liquid-cooled motor.

[0113] The level sensor array is installed in the low-temperature coolant tank 01 and the high-temperature coolant tank 05 respectively, and is used to detect the coolant level in the corresponding coolant tank. The level sensor can continuously output level data, or it can output a level status signal when the coolant level reaches the corresponding upper or lower limit.

[0114] The top drive operating condition signal interface can be connected to the top drive main control system via a fiber optic bus or other anti-interference communication lines. The motor speed signal is used to characterize the current speed of the top drive liquid-cooled motor; the torque current signal is used to characterize the current component in the motor related to the output torque; and the motor input power signal is used to characterize the current input power and load level of the motor.

[0115] The operating status signal can be input by the driller through the drill rig and sent to the top drive operating status signal interface via the top drive main control system. The operating status signal can be used to characterize the current operating state of the top drive unit, such as heavy-load drilling, variable-load operation, light-load operation, or standby. The data acquisition layer 10 sends the detection data of each sensor group and the top drive operating status signal to the intelligent control and decision layer 20 for subsequent control and status diagnosis.

[0116] In one embodiment of the present invention, the intelligent control and decision-making layer includes a signal preprocessing and transmission unit, a programmable logic controller and a human-machine interaction unit, wherein the programmable logic controller includes a core control unit and a status diagnosis unit; The signal preprocessing and transmission unit is connected to the temperature sensor group, the pressure sensor group, the flow sensor group, the liquid level sensor group and the programmable logic controller respectively. It is used to perform signal conditioning on the raw sensor signals output by each sensor group and send the signal-conditioned sensor signals to the programmable logic controller through an anti-interference communication link. The top drive condition signal interface is connected to the programmable logic controller and is used to send the top drive condition signal to the programmable logic controller. The core control unit is used to run a feedback control program, perform composite adjustment based on top drive condition feedforward and real-time temperature feedback according to the signal-conditioned sensor signal and the top drive condition signal, and generate the cooling adjustment command. The status diagnosis unit is used to determine the operating status of the top drive motor liquid cooling system based on the sensor signal after signal conditioning, and to generate early warning information when the operating status is abnormal. The human-machine interface unit is connected to the programmable logic controller and is used to output the operating status of the top drive motor liquid cooling system and the early warning information to the driller's platform.

[0117] The signal preprocessing and transmission unit is used to convert the raw sensor signals output by each sensor group into signals suitable for processing by a programmable logic controller. Signal conditioning may include at least one of signal amplification, filtering, isolation, linearization, and analog-to-digital conversion, and the specific processing method can be determined according to the output signal type of the corresponding sensor.

[0118] The signal preprocessing and transmission unit sends the conditioned sensor signal to the programmable logic controller (PLC) via an anti-interference communication link. The anti-interference communication link can employ fiber optic cables, shielded communication cables, industrial fieldbus, or other communication structures suitable for environments with high vibration and strong electromagnetic interference.

[0119] The top drive operating condition signal interface sends the top drive operating condition signal from the top drive main control system to the programmable logic controller. The top drive operating condition signal has a different source from the original sensor signals output by each sensor group; therefore, the top drive operating condition signal does not need to undergo the signal conditioning process set for the sensor output signals.

[0120] The core control unit can be implemented by a processing unit within a programmable logic controller that runs feedback control programs. The composite regulation based on top drive condition feedforward and real-time temperature feedback includes condition feedforward regulation and temperature feedback regulation.

[0121] Feedforward regulation refers to the core control unit's ability to anticipate changes in load and cooling demand of the top-drive liquid-cooled motor based on top-drive operating condition signals such as motor speed, torque current, motor input power, and operating status, and to adjust the cooling system's operating status before or during corresponding changes in motor temperature. Real-time temperature feedback regulation refers to the core control unit's adjustment of coolant flow rate and coolant temperature based on the deviations between the stator winding temperature, upper and lower bearing temperatures, and coolant inlet and outlet temperatures and their corresponding target temperatures.

[0122] The core control unit combines the operating condition feedforward adjustment results and the real-time temperature feedback adjustment results to generate a cooling adjustment command. The cooling adjustment command can at least be used to control the corresponding operating states of the circulating pump 07 and the heat exchanger 14. When the top drive motor liquid cooling system also includes the aforementioned proportional control valve, multi-way reversing valve 13, frequency converter, or refrigerant circulation loop, the cooling adjustment command can also be sent to the corresponding actuators.

[0123] The status diagnostic unit can determine whether the top drive motor liquid cooling system is in normal operation based on sensor signals such as temperature, pressure, flow rate, and liquid level. For example, when the outlet pressure of the circulating pump 07 is within the normal range, but the flow rate of the inlet branch continues to decrease, it can be determined that there may be a blockage or valve malfunction in the corresponding branch; when the liquid level of the low-temperature coolant tank 01 or the high-temperature coolant tank 05 is lower than the corresponding lower limit, a coolant shortage warning can be generated.

[0124] In one specific implementation, the status diagnosis unit can estimate the theoretical heat dissipation requirement of the motor based on the motor's input electrical power, and estimate the heat carried away by the coolant from the top-drive liquid-cooled motor based on the total coolant flow rate and the temperature difference between the coolant inlet temperature and the coolant outlet temperature. The status diagnosis unit can compare the theoretical heat dissipation requirement with the heat carried away by the coolant. When the comparison result exceeds the corresponding normal range within a predetermined time period, it can determine that the heat dissipation status of the top-drive motor liquid cooling system is abnormal and generate corresponding warning information.

[0125] The status diagnostic unit can also identify whether there is uneven coolant flow distribution among multiple top-drive liquid-cooled motors based on the flow and pressure data of different inlet branches. When the system is also equipped with temperature sensors to detect the coolant temperature at the inlet and outlet of heat exchanger 14, the status diagnostic unit can also determine the heat exchange status of heat exchanger 14 based on the changes in coolant temperature at the inlet and outlet of heat exchanger 14.

[0126] The human-machine interface unit may include a display interface and an alarm output device installed on the driller's platform. The human-machine interface unit is used to display the temperature of the top drive liquid-cooled motor, the coolant temperature, the circuit pressure, the circuit flow rate, the coolant tank level, the operating status of the circulating pump 07, and the working status of the heat exchanger 14, and outputs corresponding prompts to the driller when the status diagnosis unit generates early warning information.

[0127] Warning messages can be output in tiers based on the severity of the anomaly, and can be presented using at least one of the following formats: text, color, graphics, or sound. The programmable logic controller (PLC) can also record relevant operational data and warning messages for subsequent fault analysis and maintenance.

[0128] In one embodiment of the present invention, the number of top-drive liquid-cooled motors is two, both of which are asynchronous motors. The coolant inlets of the two top-drive liquid-cooled motors are respectively connected to the low-temperature coolant tank through parallel inlet branches, and the coolant outlets of the two top-drive liquid-cooled motors are both connected to the lower coolant tank. The proportional control valve includes a total proportional control valve disposed on the main circuit of the coolant circulation loop and two branch proportional control valves respectively disposed on the two inlet branches; The data acquisition layer includes a total flow sensor disposed on the main circuit, two branch flow sensors disposed on the two inlet branches respectively, and two branch pressure sensors disposed on the two inlet branches respectively. The total flow sensor is used to collect the total flow data in the main circuit, the two branch flow sensors are used to collect the branch flow data of the two inlet branches respectively, and the two branch pressure sensors are used to collect the branch pressure data of the two inlet branches respectively. The intelligent control and decision-making layer is also used to generate a total flow adjustment command and branch flow adjustment commands corresponding to the two liquid inlet branches based on the motor status data of the two top drive liquid-cooled motors, the total flow data, the branch flow data and branch pressure data of the two liquid inlet branches, and the top drive operating condition signal. The execution and regulation layer is also used to adjust the opening degree of the total proportional regulating valve and the rotation speed of the circulating pump according to the total flow regulation command, and to adjust the opening degree of the two branch proportional regulating valves respectively according to the two branch flow regulation commands.

[0129] This embodiment provides a shared centralized top-drive motor liquid cooling system for two asynchronous motors operating in parallel. The main loop of the coolant circulation circuit may include a common supply line between the cryogenic coolant tank 01 and the branching points of the two inlet branches. The two inlet branches extend from the branching points to the coolant inlets of the two top-drive liquid-cooled motors, respectively. The coolant discharged from the two top-drive liquid-cooled motors enters the lower coolant tank 06 together and returns to the cryogenic coolant tank 01 via the subsequent common circuit.

[0130] The overall proportional control valve is located in the main circuit and is used to regulate the total flow rate of coolant entering the two inlet branches. Two branch proportional control valves are located in the two inlet branches respectively and are used to independently regulate the flow rate of coolant flowing into the corresponding top-drive liquid-cooled motor.

[0131] A total flow sensor is installed in the main circuit to detect the total flow rate of coolant before it enters the two inlet branches. Two branch flow sensors are installed in the two inlet branches respectively to detect the flow rate into the corresponding top-drive liquid-cooled motor. Two branch pressure sensors detect the coolant pressure in the corresponding inlet branch.

[0132] The intelligent control and decision-making layer 20 can determine the cooling requirements of the two top-drive liquid-cooled motors based on their respective stator winding temperatures, upper and lower bearing temperatures, and coolant inlet and outlet temperatures. Simultaneously, the intelligent control and decision-making layer 20 determines whether the total flow rate provided by the coolant circulation loop meets the overall cooling requirements of the two top-drive liquid-cooled motors based on the total flow rate data, and determines the coolant distribution status between the two inlet branches based on the flow rate and pressure data of each branch.

[0133] When the overall cooling demand of the two top-drive liquid-cooled motors changes, the intelligent control and decision-making layer 20 generates a total flow rate adjustment command. The execution and regulation layer 30 coordinates and adjusts the opening of the total proportional control valve and the speed of the circulating pump 07 according to the total flow rate adjustment command, thereby changing the total coolant flow rate.

[0134] When the cooling requirements of the two top-drive liquid-cooled motors differ or the flow distribution of the two inlet branches deviates from the corresponding target value, the intelligent control and decision layer 20 generates flow adjustment commands for the corresponding two inlet branches. The execution and adjustment layer 30 adjusts the opening of the proportional control valves of the two branches respectively, so that the flow rate of coolant flowing into the two top-drive liquid-cooled motors matches their respective cooling requirements.

[0135] Total flow rate regulation and branch flow rate regulation can be performed in conjunction. The total proportional control valve and circulating pump 07 are used to adjust the overall liquid supply capacity of the system, while the two branch proportional control valves are used to distribute coolant between the two top-drive liquid-cooled motors, thereby reducing uneven branch flow rate distribution caused by differences in the load or flow resistance of the two motors.

[0136] In one specific application, the two asynchronous motors can each be a three-phase asynchronous motor with a rated power of 375kW and a rated current of 495A, and can be used for onshore or offshore top drive operations at a drilling depth of approximately 7000 meters. The above parameters are only one specific implementation example.

[0137] In one embodiment of the present invention, the top-drive liquid-cooled motor is a permanent magnet synchronous motor, and the motor rotor includes a rotor core and permanent magnets disposed in permanent magnet slots in the rotor core; The data acquisition layer also includes a wireless temperature sensor embedded inside the motor rotor. The wireless temperature sensor is used to detect the temperature of the permanent magnet to obtain permanent magnet temperature data. The intelligent control and decision-making layer is also used to generate permanent magnet protection adjustment commands based on the permanent magnet temperature data and the stator winding temperature data, combined with the circuit status data and the top drive condition signal. The execution and regulation layer is also used to regulate the coolant flow rate and coolant temperature according to the permanent magnet protection regulation command.

[0138] The wireless temperature sensor can be embedded in the motor rotor 420 near the permanent magnet, such as near the permanent magnet slot, between adjacent magnetic poles, or in the rotor core area that reflects the temperature of the permanent magnet. The wireless temperature sensor rotates synchronously with the motor rotor 420 and transmits the collected permanent magnet temperature data to a receiving device located on the fixed side of the motor via wireless communication. The receiving device then transmits the permanent magnet temperature data to the data acquisition layer 10.

[0139] The wireless temperature sensor can obtain the electrical energy required for operation through self-powered, inductively powered, or energy harvesting methods. The specific power supply and communication methods can be determined based on the motor speed, the internal installation space of the rotor, and the temperature detection requirements. The wireless temperature sensor and its mounting structure can be adapted to the internal temperature, vibration, and rotational load of the motor to maintain the stable position of the wireless temperature sensor within the motor rotor 420.

[0140] The intelligent control and decision-making layer 20 can continuously monitor the permanent magnet temperature data under different operating conditions of the top-drive liquid-cooled motor. Based on the permanent magnet temperature data and stator winding temperature data, the intelligent control and decision-making layer 20 determines the temperature status of the motor rotor 420 and motor stator 510, and determines the cooling requirements of the permanent magnet by combining the coolant inlet temperature, coolant outlet temperature, coolant flow rate, circuit pressure and top-drive operating condition signals.

[0141] The permanent magnet protection adjustment command may include commands to increase the target coolant flow rate or decrease the target coolant temperature. The execution and adjustment layer 30 can adjust the operating status of the circulation pump 07, the working status of the flow and direction control unit, and the heat exchange status of the power and heat exchange unit according to the permanent magnet protection adjustment command, thereby adjusting the coolant flow rate and coolant temperature.

[0142] When the top drive motor liquid cooling system also includes at least one of the aforementioned proportional control valve, multi-way reversing valve 13, frequency converter and refrigerant circulation loop, the execution and regulation layer 30 can also adjust the opening degree of the proportional control valve, the connection state of the multi-way reversing valve 13, the speed of the circulation pump 07 or the start / stop state of the compressor 08 according to the permanent magnet protection regulation command.

[0143] In one implementation, the intelligent control and decision layer 20 can also estimate the permanent magnet loss or its trend based on at least one of the following: motor speed, torque current, motor input power, and rotor position signal. When it is determined that the permanent magnet loss is about to increase, a permanent magnet protection adjustment command can be generated before the permanent magnet temperature rises significantly, so as to increase the coolant flow rate or decrease the coolant temperature in advance.

[0144] The permanent magnet temperature data can be combined with the stator winding temperature data to form motor temperature feedback. When the permanent magnet temperature reaches the corresponding protection temperature, or when the permanent magnet temperature rise rate reaches the corresponding set condition, the intelligent control and decision layer 20 can generate corresponding permanent magnet protection adjustment commands to enhance the cooling of the motor rotor 420.

[0145] When the top-drive liquid-cooled motor uses the aforementioned permanent magnet cooling channel, the status diagnosis unit can combine the permanent magnet temperature change and the heat carried away by the coolant from the top-drive liquid-cooled motor to determine whether there may be poor flow in the permanent magnet cooling channel. When the correspondence between the permanent magnet temperature change and the coolant heat exchange state is abnormal, an early warning message can be generated to prompt inspection of the internal cooling channel of the motor rotor 420.

[0146] When the top-drive liquid-cooled motor still incorporates composite phase change material within the inter-pole gap of the permanent magnet, the condition diagnostic unit can assess the heat absorption state of the composite phase change material based on the temperature rise changes of the permanent magnet under similar or identical operating conditions. When the temperature rise of the permanent magnet significantly deviates from the corresponding normal range, an early warning message can be generated to prompt an inspection of the composite phase change material's condition. This assessment result is used to indicate potential anomalies and is not directly equivalent to a determination of composite phase change material failure.

[0147] By setting permanent magnet temperature monitoring and permanent magnet protection adjustment, the top drive motor liquid cooling system can further obtain the internal temperature status of the motor rotor 420 in addition to the stator winding temperature monitoring, and adjust the coolant flow rate and coolant temperature according to the permanent magnet temperature change, thereby improving the controllability of the permanent magnet synchronous motor rotor cooling process.

[0148] In another aspect, the present invention provides a feedback control method applied to the top drive motor liquid cooling system described in any of the above embodiments. In one embodiment of the present invention, the feedback control method includes: Acquire the top drive operating condition signal and determine the top drive operating status based on the top drive operating condition signal; The corresponding cooling mode is determined based on the top drive working state, and the target temperature of the coolant, the reference flow rate of the coolant, and the initial control parameters corresponding to the cooling mode are obtained. The initial control parameters include the initial proportional coefficient, the initial integral coefficient, and the initial derivative coefficient. The real-time temperature of the coolant collected by the data acquisition layer is obtained, and the temperature deviation is determined based on the real-time temperature of the coolant and the target temperature of the coolant. Based on the initial control parameters and the temperature deviation, a proportional-integral-derivative control algorithm is used to calculate the feedback flow correction, and the target flow rate of the coolant is determined based on the coolant reference flow rate and the feedback flow correction. Generate flow regulation parameters to make the coolant flow rate reach the target flow rate of the coolant, and determine heat exchange control parameters according to the cooling mode, and generate a cooling regulation command including the flow regulation parameters and the heat exchange control parameters; The cooling adjustment command is sent to the execution and regulation layer, so that the execution and regulation layer adjusts the coolant flow rate according to the flow rate adjustment parameter, and controls the heat exchanger to exchange heat with the coolant according to the heat exchange control parameter, so as to regulate the coolant temperature.

[0149] The feedback control method of this invention can be executed by a programmable logic controller in the intelligent control and decision layer 20. The data acquisition layer 10 is used to provide motor status data, circuit status data, and top drive operating condition signals. The intelligent control and decision layer 20 is used to determine the cooling mode and generate cooling adjustment commands. The execution and adjustment layer 30 is used to execute the cooling adjustment commands to adjust the coolant flow rate and coolant temperature.

[0150] The top drive operating condition signals may include motor speed signals, torque current signals, motor input power signals, and operating status signals sent from the driller's stand to the top drive main control system. The intelligent control and decision-making layer 20 can determine the top drive operating status based on one or more of the above signals.

[0151] For example, the motor load level can be determined based on the motor input power and torque current, and the operating status of the top drive liquid-cooled motor can be determined based on the motor speed. Furthermore, operating status signals can be used to distinguish between heavy-load drilling, variable-load operation, light-load operation, and standby states. The top drive operating status can be determined through preset thresholds, status judgment rules, or a state machine.

[0152] The cooling mode indicates the cooling control method corresponding to the respective top drive operating state. Different cooling modes can correspond to different target coolant temperatures, coolant reference flow rates, and initial control parameters. After determining the top drive operating state, the intelligent control and decision layer 20 can retrieve the parameters of the corresponding cooling mode from a pre-stored control parameter table or control parameter set.

[0153] The target coolant temperature refers to the temperature that the coolant is expected to reach or maintain through cooling control. The target coolant temperature can correspond to either the coolant inlet temperature or the coolant outlet temperature. Which location's coolant temperature is used as the control target can be determined based on the control objectives of the top drive motor liquid cooling system, but the real-time coolant temperature and the target coolant temperature should correspond to the same detection location.

[0154] In one implementation, the coolant outlet temperature can be controlled to adjust the coolant flow rate based on the coolant's temperature after absorbing heat from the motor. In another implementation, the coolant inlet temperature can be controlled to regulate the temperature of the coolant supplied to the top-drive liquid-cooled motor. The coolant inlet and outlet temperatures can also be used together to reflect the temperature change of the coolant before and after flowing through the top-drive liquid-cooled motor.

[0155] The coolant reference flow rate refers to the coolant flow rate preset to meet basic cooling requirements under the corresponding top drive operating conditions and cooling modes. The coolant reference flow rate can be determined based on the motor's rated power, the expected heat generation under the corresponding operating conditions, the temperature difference between the coolant inlet and outlet, the specific heat capacity of the coolant, and the heat exchange capacity of the coolant circulation loop.

[0156] The initial control parameters refer to the initial parameters used by the proportional-integral-derivative (PID) control algorithm when entering the corresponding cooling mode, including the initial proportional coefficient, initial integral coefficient, and initial derivative coefficient. These initial control parameters can be determined in advance through experiments, thermal simulations, historical operating data, or engineering tuning methods, and stored in the intelligent control and decision layer 20. After the top drive motor liquid cooling system is operational, the proportional coefficient, integral coefficient, and derivative coefficient can be adjusted within permissible ranges based on temperature response and changes in operating conditions.

[0157] To illustrate the temperature change characteristics of the top drive device, in a simplified thermal model, the temperature change of the top drive device or the selected temperature sensing object can be expressed as:

[0158] In the formula, For time The temperature of the top drive device or the selected temperature detection object. This refers to the ambient temperature or a corresponding reference temperature. The equivalent heat transfer coefficient, The equivalent heat capacity parameter is used to characterize the thermal inertia of the top drive device or the corresponding temperature detection object.

[0159] Equation (1) is a simplified model used to describe the temperature response inertia and heat transfer trend. When the changes in the internal heat source are neglected or equivalently treated, when... Higher than hour, Over time Reduce. In actual operation, the heat generation of the motor can also be estimated based on the input power, torque current and top drive conditions, and the corresponding thermal model parameters can be corrected accordingly. Formula (1) can be used to help determine the target temperature of the coolant, the reference flow rate of the coolant and the initial control parameters under different operating conditions. It is not required to solve the formula online in every control cycle.

[0160] The data acquisition layer 10 can acquire the real-time temperature of the coolant according to a predetermined sampling period. The temperature deviation between the real-time coolant temperature and the corresponding target coolant temperature can be expressed as:

[0161] In the formula, For time Temperature deviation at time This refers to the real-time temperature of the coolant. This refers to the target temperature of the coolant under the corresponding cooling mode.

[0162] According to the definition of formula (2), when the real-time temperature of the coolant is higher than the target temperature of the coolant, the temperature deviation is positive; when the real-time temperature of the coolant is lower than the target temperature of the coolant, the temperature deviation is negative. The intelligent control and decision layer 20 can determine the degree to which the coolant flow rate needs to be increased or decreased based on the magnitude and trend of the temperature deviation.

[0163] The proportional-integral-derivative (PID) control algorithm can be expressed as:

[0164] In the formula, This refers to the flow control quantity output by the proportional-integral-derivative (PID) control algorithm, and its unit can be L / min. , and These are the proportional coefficient, integral coefficient, and differential coefficient, respectively. For time Temperature deviation at that time; It is the integral variable.

[0165] The proportional control term generates a corresponding control quantity based on the current temperature deviation, enabling the cooling system to respond to the current temperature deviation; the integral control term accumulates the temperature deviation over a period of time to reduce the persistent steady-state temperature deviation; and the derivative control term generates a corresponding control quantity based on the rate of change of the temperature deviation to reflect the temperature change trend and suppress excessive temperature fluctuations.

[0166] When the proportional-integral-derivative control algorithm directly outputs the coolant flow rate This can be used as the target flow rate for the coolant. When using the control method combining the reference flow rate and feedback correction in this embodiment, As a feedback flow correction amount, that is:

[0167] The target flow rate of the coolant can be expressed as:

[0168] In the formula, For the target flow rate of the coolant, This is the reference flow rate of the coolant corresponding to the current cooling mode. This is for feedback flow correction.

[0169] In practical implementation, the target flow rate of the coolant can be limited based on the minimum and maximum allowable flow rates of the coolant circulation loop to prevent the target flow rate from exceeding the allowable operating range of the circulation pump 07, connecting pipes, or the internal flow channels of the top-drive liquid-cooled motor. Integral limiting can also be applied to the integral control term, and filtering can be applied to the derivative control term to reduce the impact of excessive integral accumulation or temperature detection noise on the control results.

[0170] Flow regulation parameters refer to the execution control parameters used to ensure that the actual flow rate of the coolant reaches the target flow rate. Flow regulation parameters may include at least the operating parameters of the circulating pump 07. When the top drive motor liquid cooling system also includes a frequency converter or a proportional control valve, the flow regulation parameters may further include the target frequency of the frequency converter, the target speed of the circulating pump 07, or the target opening degree of the proportional control valve.

[0171] The intelligent control and decision-making layer 20 can acquire the real-time coolant flow rate collected by the data acquisition layer 10, and determine the flow regulation parameters based on the difference between the target coolant flow rate and the real-time coolant flow rate. For example, when the real-time coolant flow rate is lower than the target coolant flow rate, the operating output of the circulating pump 07 can be increased; when the system also includes a frequency converter or a proportional control valve, the target frequency of the frequency converter can be increased, the target speed of the circulating pump 07 can be increased, or the target opening of the proportional control valve can be increased.

[0172] The heat exchange control parameters are used to control the state of coolant flow through heat exchanger 14 or the heat exchange capacity of heat exchanger 14. The heat exchange control parameters may include at least the operating parameters of the heat exchange medium circulation equipment connected to heat exchanger 14. When the system includes a multi-way directional valve 13, the heat exchange control parameters may include the target connection state of the multi-way directional valve 13; when the system also includes a refrigerant circulation loop, the heat exchange control parameters may also include the cooling start / stop state of the refrigerant circulation loop.

[0173] The intelligent control and decision-making layer 20 determines the heat exchange control parameters based on the cooling mode. For example, in heavy-load cooling mode, the coolant can flow through the heat exchanger 14 to increase the heat exchange capacity; in standby cooling mode, the heat exchange capacity can be reduced. When the system includes a bypass circulation path and a heat exchange circulation path, the appropriate flow path can be selected according to the cooling mode.

[0174] The intelligent control and decision-making layer 20 combines the flow regulation parameters and heat exchange control parameters to form a cooling regulation command, and sends the cooling regulation command to the execution and regulation layer 30. The execution and regulation layer 30 controls the circulating pump 07 or the corresponding flow regulation component according to the flow regulation parameters to make the coolant flow rate approach the target coolant flow rate; and controls the heat exchange path of the coolant or the heat exchange state of the heat exchanger 14 according to the heat exchange control parameters to regulate the coolant temperature.

[0175] The above feedback control process can be repeated according to a predetermined control cycle. After the execution and adjustment layer 30 completes one adjustment, the data acquisition layer 10 re-acquires the coolant temperature, coolant flow rate and other status data. The intelligent control and decision layer 20 calculates the cooling adjustment command for the next control cycle based on the re-acquired data, thereby forming a closed-loop feedback control.

[0176] like Figure 6 As shown, in one specific implementation, the current drilling parameters, such as torque, motor input power, and motor speed, are first input or acquired. The top drive operating condition signals are then used to determine the top drive's working state. The cooling mode is determined based on the top drive's working state. The corresponding coolant target temperature, coolant reference flow rate, and initial proportional coefficient, initial integral coefficient, and initial derivative coefficient are called according to the cooling mode. The data acquisition layer 10 collects and feeds back the real-time coolant temperature and real-time coolant flow rate. The intelligent control and decision layer 20 calculates the coolant target flow rate based on the temperature deviation and the proportional-integral-derivative control algorithm, and determines whether the coolant flow rate and the working state of the heat exchanger 14 need to be adjusted. Subsequently, a cooling adjustment command is generated and sent to the execution and adjustment layer 30, which controls the corresponding execution components to achieve cooling adjustment under different drilling conditions.

[0177] When the system also includes a proportional control valve, a multi-way reversing valve 13, a frequency converter, or a refrigerant circulation loop, the execution and regulation layer 30 can control the corresponding valves, frequency converter, or compressor 08 to operate according to the cooling regulation command.

[0178] Figure 6The driller's control panel can be used to input operating conditions, work plans, or manual intervention information. The intelligent control and decision-making layer 20 can use this information as part of the top drive operating condition signal. Whether to adjust the coolant flow rate and the operating status of the heat exchanger 14 is mainly determined automatically by the intelligent control and decision-making layer 20 based on the top drive operating condition signal and real-time detection data. When manual intervention is required, the driller can also input corresponding control requests or adjustment requirements through the driller's control panel.

[0179] In one embodiment of the present invention, the top drive working state includes top drive heavy-load drilling state, top drive variable load operation state, top drive light-load operation state and top drive standby state. The top drive heavy-load drilling state corresponds to the heavy-load cooling mode, the top drive variable-load operation state corresponds to the variable-load cooling mode, the top drive light-load operation state corresponds to the light-load cooling mode, and the top drive standby state corresponds to the standby cooling mode. The heavy-load cooling mode, the variable-load cooling mode, the light-load cooling mode, and the standby cooling mode are each equipped with a corresponding preset target coolant temperature, preset coolant reference flow rate, and preset initial control parameters.

[0180] Top-drive heavy-duty drilling mode refers to the working state in which the top-drive liquid-cooled motor continuously outputs a large torque or a large power to drive the drill bit for drilling. Heavy-duty cooling mode can use a relatively low preset target coolant temperature, a relatively large preset coolant reference flow rate, and a relatively large initial proportional coefficient, enabling the cooling system to respond quickly to temperature changes. When the system includes a heat exchange circulation path or a refrigerant circulation loop, in heavy-duty cooling mode, the coolant can also flow through the heat exchanger 14, and the compressor 08 can be started according to cooling requirements.

[0181] Top drive variable load operation state refers to a working state in which the motor load changes significantly with drilling pressure, drill string condition, or drilling operation. The variable load cooling mode can use a preset target coolant temperature and a preset reference coolant flow rate adapted to the load variation range. The initial proportional coefficient can be set to a moderate value, and the initial derivative coefficient can be set to a relatively large value to improve the control system's responsiveness to temperature change trends and reduce temperature fluctuations.

[0182] The top drive light-load operation mode refers to the continuous operation of the top drive liquid-cooled motor under relatively low load. The light-load cooling mode can use a relatively high preset target coolant temperature and a relatively low preset reference coolant flow rate. The initial proportional coefficient can be set to a relatively small value, and the initial integral coefficient can be set to a relatively large value to maintain coolant temperature stability while reducing flow rate fluctuations.

[0183] The top drive standby state refers to the top drive liquid-cooled motor not performing drilling operations or being in a low-power waiting state. The standby cooling mode can use corresponding preset coolant target temperature, preset coolant reference flow rate, and preset initial control parameters. The preset coolant reference flow rate in standby cooling mode can be zero or a low flow rate sufficient to maintain basic circulation. The initial proportional coefficient, initial integral coefficient, and initial derivative coefficient can be set to zero or their corresponding standby values. When the motor temperature and coolant temperature are within allowable ranges, the operating output of the cooling system can be reduced; when the system includes a refrigerant circulation loop, compressor 08 can also be stopped.

[0184] The initial control parameters corresponding to different cooling modes can be summarized as follows:

[0185] Formula (6) is used to illustrate the relative setting relationship of the initial control parameters under different cooling modes, and does not limit the specific values ​​of each parameter. Each parameter can be adjusted according to the heat capacity of the top-drive liquid-cooled motor, the response time of the coolant circulation loop, the heat exchange capacity of the heat exchanger 14, and the temperature control requirements under the corresponding operating conditions.

[0186] By setting corresponding cooling modes for different top drive operating conditions, it is possible to avoid using the same coolant flow rate and control parameters under all operating conditions. This improves cooling response under heavy load conditions and reduces unnecessary cooling output under light load or standby conditions, thus adapting the cooling system's operating state to the top drive's operating state.

[0187] In one embodiment of the present invention, when the top drive is in the top drive variable load operation state, determining the target coolant flow rate based on the coolant reference flow rate and the feedback flow rate correction includes: Obtain load change parameters to characterize the expected load change, the load change parameters including at least one of torque change parameters and motor input power change parameters; The feedforward flow correction amount is determined based on the load change parameters; The target flow rate of the coolant is determined based on the coolant reference flow rate, the feedback flow correction, and the feedforward flow correction.

[0188] Load variation parameters are used to characterize the load changes that the top drive liquid-cooled motor may experience over a period of time. Torque variation parameters can be determined based on the expected amount and rate of change of torque current or the drilling operation plan input from the driller's rig; motor input power variation parameters can be determined based on the expected amount and rate of change of motor input power or a preset value.

[0189] Load change parameters can be calculated by the top drive main control system based on real-time motor operating data, or determined based on the pre-entered operating status or load adjustment plan on the driller's stand. Therefore, the intelligent control and decision-making layer 20 can obtain expected load change information before a significant change in motor temperature occurs.

[0190] The intelligent control and decision-making layer 20 can determine the feedforward flow correction amount based on the preset correspondence between load change parameters and cooling demand, lookup tables, or thermal models. When the load change parameters indicate that the motor load is expected to increase, the feedforward flow correction amount can be positive; when the load change parameters indicate that the motor load is expected to decrease, the feedforward flow correction amount can be negative or zero.

[0191] After introducing the feedforward flow correction, the target coolant flow rate can be expressed as:

[0192] In the formula, For the target flow rate of the coolant, This is the reference flow rate of the coolant corresponding to the variable load cooling mode. This is the feedback flow correction amount calculated based on the temperature deviation. This is the feedforward flow correction amount determined based on load variation parameters.

[0193] The feedback flow correction is used to correct temperature deviations already reflected in the real-time coolant temperature, while the feedforward flow correction is used to address anticipated load changes not yet fully reflected in the real-time coolant temperature. By combining both into the coolant reference flow rate, the cooling system can respond to varying load conditions in advance while maintaining closed-loop temperature feedback control.

[0194] In one specific implementation, when the torque or motor input power is expected to increase, the intelligent control and decision layer 20 can increase the target coolant flow rate before the coolant temperature rises significantly, and send a corresponding cooling adjustment command to the execution and regulation layer 30. The execution and regulation layer 30 increases the operating output of the circulating pump 07 in advance; when the system also includes a frequency converter or a proportional control valve, it can also increase the speed of the circulating pump 07 or increase the opening of the proportional control valve. After the temperature change occurs, the proportional-integral-derivative control algorithm continues to calculate the feedback flow correction amount based on the real-time temperature deviation, and performs closed-loop correction on the feedforward regulation result.

[0195] In an alternative implementation, a model predictive control unit can be set up based on the aforementioned combined control of operating condition feedforward and temperature feedback. The model predictive control unit can predict the changes in motor temperature or coolant temperature within a preset time range based on motor state data, loop state data, top drive operating condition signals, and the dynamic thermal model of the top drive motor liquid cooling system, and adjust the target flow rate of coolant, heat exchange control parameters, or cooling mode according to the prediction results.

[0196] For example, when drilling pressure changes abruptly, torque increases, or motor input power increases, the model predictive control unit can predict the temperature rise trend based on load changes and increase the coolant flow rate or enhance the heat exchange state of heat exchanger 14 before the temperature reaches the corresponding control limit, so as to reduce the response lag of the control system caused by thermal inertia.

[0197] In another optional implementation, an adaptive optimization unit can be set up to adjust the control parameters. The adaptive optimization unit can use deep reinforcement learning methods to take the adjustment of the proportional coefficient, integral coefficient, and derivative coefficient, as well as the cooling mode switching command, as optional control actions, and construct corresponding evaluation indicators based on the temperature control effect and the energy consumption of the cooling system.

[0198] The adaptive optimization unit can adjust control parameters or cooling modes based on historical operating data generated from different well sites, ambient temperatures, top drive operation status, and equipment operating time. The model predictive control unit or adaptive optimization unit can be configured in parallel with the programmable logic controller (PLC), or it can serve as a higher-level parameter optimization module for the PLC.

[0199] The adjustment amounts of control parameters, coolant reference flow rate, or cooling mode switching suggestions output by the model predictive control unit or adaptive optimization unit can be verified within permissible ranges and judged for safety conditions by the programmable logic controller (PLC). After verification that the preset safety conditions are met, the PLC generates a cooling adjustment command based on the corresponding results and sends it to the execution and adjustment layer 30.

[0200] The above method can combine the feedforward regulation of the operating condition corresponding to the top drive working state with the feedback regulation corresponding to the real-time temperature of the coolant, and adopt the corresponding target temperature, reference flow rate and initial control parameters of the coolant according to different top drive working states, so that the coolant flow rate and heat exchange state can be adjusted with the top drive load and temperature changes.

[0201] The present invention will be further described below with reference to two specific embodiments.

[0202] Example 1: This embodiment addresses conventional top drive operations on onshore or offshore drilling platforms at a drilling depth of approximately 7000 meters. The top drive unit is equipped with two parallel-running three-phase asynchronous motors, each with a rated power of 375kW and a rated current of 495A. Considering the high ambient temperature and strong vibration at the drilling site, and the need for continuous heavy-load and variable-load operations, this embodiment configures a shared centralized top drive motor liquid cooling system for the two three-phase asynchronous motors.

[0203] I. Top-drive liquid-cooled asynchronous motor: In this embodiment, the rotor shaft 410 of each top-drive liquid-cooled asynchronous motor is forged from high-strength alloy steel and is configured as a hollow structure. The central through hole of the rotor shaft 410 constitutes the main cooling channel extending along its axial direction.

[0204] The rotor shaft 410 has at least three radial oblique holes below the upper bearing chamber 200. These radial oblique holes are evenly distributed along the circumference of the rotor shaft 410 and form a first diversion channel communicating with the upper cooling chamber 02. At a position corresponding to the lower end of the rotor core of the motor rotor 420, the rotor shaft 410 also has a set of radial holes. These radial holes form a second diversion channel communicating with the lower cooling chamber 03.

[0205] The motor rotor 420 includes a rotor core, rotor bars disposed within the rotor core, and rotor end rings disposed at both ends of the rotor bars. The structure of the rotor end rings can be configured according to the flow direction of the coolant to increase the heat exchange contact area between the rotor end rings and the coolant.

[0206] The stator core of the motor stator 510 is formed by stacking multiple stator laminations made of silicon steel. Each stator lamination is provided with a circumferential liquid passage. The multiple stator laminations are arranged in a staggered stacking manner, so that the circumferential liquid passages on adjacent stator laminations are connected in sequence, forming a continuous three-dimensional meandering cooling channel in the stator core.

[0207] The motor housing 700 has a casing flow channel cast inside, which matches the grooves on the outside of the stator core. The casing flow channel and the three-dimensional meandering cooling channel inside the stator core are connected through the flow channel inlet and flow channel outlet set on the motor housing 700, which together form the cooling flow path of the motor stator 510.

[0208] At least one location in the rotor bar region and the rotor end ring region of the motor rotor 420 is provided with a composite phase change material for absorbing transient heat. The composite phase change material is used to absorb the transient heat generated by the rotor bar and rotor end ring during transient overload or sudden load changes in the motor, so as to buffer local temperature changes in the rotor and reduce the thermal stress generated by repeated thermal shocks.

[0209] The cooling process of the top-drive liquid-cooled asynchronous motor is as follows: The coolant is stored in the low-temperature coolant tank 01 and is pumped by the circulating pump 07 through the coolant inlet at the top of the top-drive liquid-cooled motor to the upper bearing chamber 200. After flowing through the upper bearing, the coolant enters the main cooling channel inside the rotor shaft 410.

[0210] A portion of the coolant in the main cooling channel enters the upper cooling chamber 02 through radial oblique holes to cool the upper rotor end ring, the upper end of the stator winding, and the upper inner wall of the motor housing 700; another portion of the coolant enters the lower cooling chamber 03 through the radial hole at the lower end of the rotor shaft 410 to cool the lower rotor end ring, the lower end of the stator winding, and the lower inner wall of the motor housing 700; the remaining coolant continues to flow downward along the main cooling channel and enters the lower bearing chamber 04 to cool the lower bearing.

[0211] The coolant entering the motor stator 510 cooling path flows along the three-dimensional meandering cooling channel and the housing flow channel to remove heat from the stator core and the motor housing 700. The coolant flowing through the upper cooling chamber 02, the lower cooling chamber 03, the stator cooling path and the lower bearing chamber 04 finally collects at the lower end of the motor and is discharged to the lower coolant tank 06 through the coolant outlet.

[0212] In one specific flow configuration, all coolant entering from the coolant inlet first flows through the upper bearing chamber 200, and after cooling the upper bearing, enters the main cooling channel inside the rotor shaft 410. The coolant entering the main cooling channel is distributed according to the cooling requirements of the upper cooling chamber 02, the lower cooling chamber 03, and the lower bearing chamber 04. Specifically, a portion of the coolant enters the upper cooling chamber 02 via the first diversion channel, a portion enters the lower cooling chamber 03 via the second diversion channel, and the remaining coolant continues along the main cooling channel into the lower bearing chamber 04. The flow ratio of each portion of the coolant can be determined based on the heat generation of the corresponding cooling object, the required cooling capacity, and the flow resistance of each channel, and can be configured by adjusting the number, orifice diameter, and extension direction of the first and second diversion channels.

[0213] II. Liquid cooling system for top drive motors used with two asynchronous motors: This embodiment sets up a shared centralized top drive liquid-cooled asynchronous motor liquid cooling system for two top drive liquid-cooled asynchronous motors operating in parallel. The coolant inlets of the two top drive liquid-cooled asynchronous motors are connected to the low-temperature coolant tank 01 through parallel inlet branches, and the coolant outlets of the two top drive liquid-cooled asynchronous motors are both connected to the lower coolant tank 06.

[0214] The lower coolant tank 06 receives the coolant discharged from the two top-drive liquid-cooled asynchronous motors and transports the coolant to the high-temperature coolant tank 05. The coolant in the high-temperature coolant tank 05 is heated by the heat exchanger 14 and filtered by the filter 09 before returning to the low-temperature coolant tank 01, thus forming a closed-loop coolant circulation.

[0215] The data acquisition layer 10 includes a temperature sensor group, a pressure sensor group, a flow sensor group, a liquid level sensor group, and a top drive operating condition signal interface. Each top drive liquid-cooled asynchronous motor can be equipped with no fewer than eight temperature measuring points, which may include the three-phase stator windings, the upper bearing, the lower bearing, the coolant inlet, the coolant outlet, and the internal cavity of the motor. The system is also equipped with a temperature sensor for detecting ambient temperature, and other temperature measuring points can be set according to actual monitoring needs.

[0216] Flow sensors are installed in the main circuit of the coolant circulation loop and on the inlet branch of each top-drive liquid-cooled asynchronous motor. Pressure sensors are installed at the outlet of circulation pump 07, in the main circuit of the coolant circulation loop, and on the inlet branch of each top-drive liquid-cooled asynchronous motor. Level sensors are installed in the low-temperature coolant tank 01 and the high-temperature coolant tank 05.

[0217] The top drive operating condition signal interface communicates with the top drive main control system via a fiber optic bus to acquire motor speed signals, torque current signals, motor input power signals, and operating condition status signals sent from the driller's platform to the top drive main control system.

[0218] The intelligent control and decision-making layer 20 is based on a programmable logic controller (PLC) configured in the top drive unit. The PLC determines the top drive's operating state based on received top drive operating condition signals and calls the corresponding cooling mode. During the control process, the real-time coolant temperature can be used as the primary feedback control variable, and the stator winding temperature and the temperatures of the upper and lower bearings can be used as the basis for motor temperature monitoring and protection.

[0219] Under heavy-load drilling conditions on the top drive, a heavy-load cooling mode can be activated, employing a relatively large coolant reference flow rate and a relatively large initial proportional coefficient to improve the cooling system's responsiveness to temperature changes. Under variable-load operation conditions on the top drive, a variable-load cooling mode can be activated, and the target coolant flow rate can be pre-adjusted based on anticipated torque changes or motor input power changes, while using a moderate initial proportional coefficient and a relatively large initial derivative coefficient. Under light-load operation conditions on the top drive, a light-load cooling mode can be activated, employing a relatively small coolant reference flow rate and an initial proportional coefficient, with an appropriately increased initial integral coefficient. In standby mode on the top drive, low-flow circulation or disabling active cooling can be used.

[0220] The execution and regulation layer 30 includes a flow and direction control unit and a power and heat exchange unit. A total proportional regulating valve is installed on the main loop of the coolant circulation loop, and branch proportional regulating valves are installed on the inlet branches of the two top-drive liquid-cooled asynchronous motors to regulate the total flow of coolant and distribute coolant between the two motors.

[0221] A multi-way reversing valve 13 is also provided in the coolant circulation loop to switch between the bypass circulation path of the coolant bypassing the heat exchanger 14 and the heat exchange circulation path of the coolant flowing through the heat exchanger 14. The circulation pump 07 is connected to a frequency converter drive, which adjusts the speed of the circulation pump 07 according to the cooling adjustment command generated by the programmable logic controller.

[0222] The power and heat exchange unit may also include a refrigerant circulation loop consisting of a compressor 08, a condenser 12, a throttle valve 11, and a heat exchanger 14. When the top-drive liquid-cooled asynchronous motor is in a heavy-load drilling state, the ambient temperature is high, or the coolant temperature reaches the corresponding refrigeration start-up conditions, the programmable logic controller can start the compressor 08, so that the refrigerant circulation loop actively cools the coolant through the heat exchanger 14.

[0223] III. System Workflow and Feedback Control: After the system starts, the programmable logic controller (PLC) reads the top drive operating condition signal and determines the top drive's operating status and corresponding cooling mode based on the signal. When it is determined that the top drive is in a heavy-load drilling state, the main proportional control valve and the two branch proportional control valves can be adjusted to their respective initial openings, and the refrigerant circulation loop can be started based on the motor status data and loop status data.

[0224] Under variable load conditions, the programmable logic controller can determine the feedforward flow correction amount based on at least one of the torque change parameters and the motor input power change parameters, and adjust the speed of the circulating pump 07 and the opening of the corresponding branch proportional regulating valve in advance before the corresponding load change is fully reflected in the coolant temperature.

[0225] The data acquisition layer 10 collects real-time coolant temperature and real-time coolant flow rate according to a predetermined sampling period. The programmable logic controller (PLC) compares the real-time coolant temperature with the target coolant temperature under the corresponding cooling mode to obtain the temperature deviation, and uses a proportional-integral-derivative (PID) control algorithm to calculate the feedback flow correction. Based on the coolant reference flow rate, the feedback flow correction, and the feedforward flow correction, the PLC determines the target coolant flow rate and generates corresponding cooling adjustment commands.

[0226] The execution and regulation layer 30 adjusts the speed of the circulating pump 07, the opening of the total proportional regulating valve, and the opening of the two branch proportional regulating valves according to the cooling regulation command, so that the total flow rate of coolant and the flow rate of coolant in the two inlet branches are adapted to the cooling requirements of the two top-drive liquid-cooled asynchronous motors.

[0227] The condition diagnostic unit can estimate the theoretical heat dissipation requirements of the motor based on the motor's input electrical power, and estimate the heat carried away from the motor by the coolant based on the total coolant flow rate and the temperature difference between the coolant inlet and outlet. When the relationship between the two deviates from the normal range within a predetermined period of time, or when the flow rate or pressure of a certain motor inlet branch becomes abnormal, the condition diagnostic unit generates corresponding early warning information.

[0228] The human-machine interface unit can display the operating status and warning information of the top drive motor liquid cooling system on the driller's stand, and record the corresponding operating data. The warning information can be graded using preset colors such as yellow, so that operators can check the corresponding coolant lines, valves or heat exchangers 14.

[0229] IV. Implementation Results: The above structure and control method allow for centralized cooling of two parallel top-drive liquid-cooled asynchronous motors, with separate adjustments to the coolant flow rates of the two inlet branches. The coolant inside the motor effectively cools the stator winding ends, rotor end rings, upper and lower bearings, and the motor housing 700, reducing localized heat buildup within the motor.

[0230] The control method, which combines operating condition feedforward and temperature feedback, allows the coolant flow rate and heat exchange status to be adjusted according to the top drive's operating status and temperature changes. Reducing the cooling system's operating output during light load operation or standby helps minimize unnecessary cooling energy consumption. The condition diagnostic function can also alert users to potential flow channel blockages, heat exchange anomalies, or uneven branch flow distribution based on temperature, pressure, and flow rate data.

[0231] Example 2: This embodiment addresses direct-drive top-drive operations on onshore or offshore drilling platforms at a drilling depth of approximately 7000 meters. The direct-drive top-drive unit is equipped with a built-in permanent magnet synchronous motor with a rated power of 735kW and a rated current of 850A. The permanent magnet direct-drive top-drive unit can operate without a gearbox, placing high demands on the motor's torque density and operational reliability. This embodiment configures the permanent magnet synchronous motor with a liquid-cooling system that integrates cooling for the motor stator, rotor, and permanent magnets.

[0232] I. Top-drive liquid-cooled permanent magnet synchronous motor: In this embodiment, the rotor shaft 410 of the top-drive liquid-cooled permanent magnet synchronous motor is forged from high-strength non-magnetic alloy steel and is configured as a hollow structure. The central through hole of the rotor shaft 410 forms an axially extending main cooling channel.

[0233] The motor rotor 420 includes a rotor core and permanent magnets disposed in permanent magnet slots within the rotor core. Multiple sets of permanent magnet cooling channels are arranged axially within the rotor core. These cooling channels are parallel to the permanent magnet slots and extend along the back of the corresponding permanent magnets. Each set of permanent magnet cooling channels is connected to the main cooling channel via radial branch pipes, allowing the coolant in the main cooling channel to enter the permanent magnet cooling channel through the radial branch pipes and flow along the back of the permanent magnets.

[0234] The stator core of the motor stator 510 is formed by segmented and staggered stacking of silicon steel sheets, creating a three-dimensional meandering cooling channel inside the stator core. The cross-sectional area and extension path of the three-dimensional meandering cooling channel can be determined based on the electromagnetic load of the permanent magnet synchronous motor and the required coolant flow rate.

[0235] The motor housing 700 has an inner cooling channel and an outer cooling channel located outside the inner cooling channel. The inner cooling channel is arranged along the outer circumferential surface of the stator core and is in close contact with the outer circumferential surface of the stator core to form a heat dissipation area that is tightly coupled with the stator core; the outer cooling channel is used for the circulation of coolant.

[0236] A composite phase change material for absorbing transient heat can be placed within the interpole gap of the permanent magnet. This composite phase change material works in conjunction with the coolant channels on the back of the permanent magnet. During continuous motor operation, the coolant carries away the heat generated by the permanent magnet, while during transient overload of the motor, the composite phase change material absorbs the transient heat.

[0237] The cooling process of the top-drive liquid-cooled permanent magnet synchronous motor is as follows: Coolant enters the upper bearing chamber 200 through the coolant inlet at the non-drive end of the motor, and after cooling the upper bearing, it enters the main cooling channel inside the rotor shaft 410. Part of the coolant in the main cooling channel enters the upper cooling chamber 02 through the first branch channel, part of the coolant enters the permanent magnet cooling channel through the radial branch pipe and flows along the back of the permanent magnet, and another part of the coolant enters the lower cooling chamber 03 through the second branch channel.

[0238] The coolant flowing through the upper cooling chamber 02 and the lower cooling chamber 03 cools the upper and lower ends of the motor rotor 420, the upper and lower ends of the stator windings, and the corresponding inner walls of the motor housing 700, respectively. The coolant entering the stator cooling path carries away heat from the stator core and the motor housing 700. The coolant flowing through the permanent magnet cooling channel carries away heat generated by the permanent magnet and the surrounding rotor core. The coolant flowing through the first branch channel, the second branch channel, the permanent magnet cooling channel, and the stator cooling path flows towards the motor drive end; the coolant continuing to flow along the main cooling channel after branching enters the lower bearing chamber 04 and cools the lower bearing. All coolants ultimately converge at the motor drive end and are discharged through the coolant outlet.

[0239] II. Liquid cooling system for top drive motors used in permanent magnet synchronous motors: The top drive motor liquid cooling system in this embodiment uses the aforementioned low-temperature coolant tank 01, lower coolant tank 06, high-temperature coolant tank 05, circulating pump 07, heat exchanger 14, filter 09, and connecting pipelines to form a closed coolant circulation loop. The intelligent control and decision-making layer 20 and the execution and regulation layer 30 can adopt the same or similar structure as in Embodiment 1.

[0240] In addition to detecting stator winding temperature, upper and lower bearing temperatures, coolant inlet and outlet temperatures, circuit pressure, circuit flow rate, and coolant tank level, the data acquisition layer 10 also includes a wireless temperature sensor embedded inside the motor rotor 420. The wireless temperature sensor is positioned to reflect the temperature of the permanent magnet and rotates synchronously with the motor rotor 420, transmitting the permanent magnet temperature data wirelessly to a receiving device located on the fixed side of the motor.

[0241] This embodiment can set multiple temperature measuring points according to the motor power, structural dimensions, and temperature monitoring requirements; for example, approximately fifteen temperature measuring points can be set. The specific number of temperature measuring points does not constitute a limitation on this embodiment.

[0242] III. System Workflow and Permanent Magnet Protection: After the system starts up, the programmable logic controller performs self-tests on the temperature sensor, wireless communication link, circulating pump 07 and corresponding execution components, and continuously acquires permanent magnet temperature data in each cooling mode.

[0243] The intelligent control and decision-making layer 20 determines the cooling requirements of the permanent magnet and generates permanent magnet protection and adjustment commands based on the permanent magnet temperature data and stator winding temperature data, combined with the coolant inlet temperature, coolant outlet temperature, circuit pressure, circuit flow rate and top drive operating condition signals.

[0244] Under variable load conditions, the intelligent control and decision-making layer 20 can also estimate the permanent magnet loss or its trend based on at least one of the following: motor speed, torque current, motor input power, and rotor position signal. When it is determined that the permanent magnet loss is expected to increase, a permanent magnet protection adjustment command can be generated before the permanent magnet temperature rises significantly, thereby increasing the target coolant flow rate or decreasing the target coolant temperature in advance.

[0245] The execution and regulation layer 30 adjusts the operating status of the circulating pump 07, the coolant flow rate, and the heat exchange status of the heat exchanger 14 according to the permanent magnet protection regulation command. When the system includes at least one of a proportional control valve, a multi-way reversing valve 13, a frequency converter driver, and a refrigerant circulation loop, the opening degree of the proportional control valve, the connection state of the multi-way reversing valve 13, the speed of the circulating pump 07, or the start / stop state of the compressor 08 can also be adjusted accordingly.

[0246] The permanent magnet temperature data and stator winding temperature data can be used as feedback for motor temperature protection, while the real-time coolant temperature can be used as the temperature input for coolant flow feedback control. The intelligent control and decision layer 20 determines the temperature deviation based on the real-time coolant temperature and the target coolant temperature, and calculates the feedback flow correction using a proportional-integral-derivative (PID) control algorithm. Simultaneously, it generates corresponding permanent magnet protection adjustment quantities based on the permanent magnet temperature and its changing trend. These permanent magnet protection adjustment quantities can be superimposed on the corresponding cooling regulation commands.

[0247] When a top-drive liquid-cooled permanent magnet synchronous motor uses a permanent magnet cooling channel, the status diagnostic unit can determine whether there may be obstruction in the permanent magnet cooling channel by combining the permanent magnet temperature change, the top drive operating condition, and the heat carried away by the coolant from the top drive liquid-cooled motor. When the correlation between the permanent magnet temperature change and the top drive operating condition and the overall heat exchange state of the coolant is abnormal, an early warning message can be generated to prompt inspection of the permanent magnet cooling channel.

[0248] When a composite phase change material is placed within the gap between the permanent magnet poles, the condition diagnostic unit can also assess the heat absorption state of the composite phase change material based on the temperature rise changes of the permanent magnet under the same or similar operating conditions. When the temperature rise of the permanent magnet deviates significantly from the corresponding normal range, a high-level warning message can be generated to prompt an inspection of the composite phase change material's condition. The above assessment is used to indicate potential anomalies and does not directly equate to determining that the composite phase change material has failed.

[0249] IV. Expected Technical Results: Through the implementation of this embodiment, the coolant channel on the back of the permanent magnet can continuously remove the heat generated by the permanent magnet and the surrounding rotor core. The composite phase change material set in the inter-pole gap of the permanent magnet can absorb transient heat during transient overload, thereby mitigating the rapid rise in permanent magnet temperature, reducing the risk of thermal demagnetization of the permanent magnet, and providing heat dissipation conditions for improving the torque density and power density of the motor. The intelligent control and decision layer 20 can adjust the coolant flow rate and temperature according to the permanent magnet temperature, stator winding temperature, circuit status, and top drive operating conditions, which helps to reduce unnecessary cooling output under light load or standby conditions. The buffering effect of the composite phase change material on transient thermal shock also helps to reduce temperature fluctuations and thermal cycle stress of motor components. By monitoring the permanent magnet temperature and its relationship with the heat exchange state of the coolant, the system can indicate possible abnormalities in the permanent magnet cooling channel or composite phase change material, improving the monitorability and operational reliability of the cooling process of the permanent magnet direct drive top drive system.

[0250] As can be seen from the above embodiments of the present invention, the top-drive liquid-cooled motor, the top-drive motor liquid-cooling system, and the feedback control method of the present invention achieve at least the following beneficial effects: 1. This invention, by setting a main cooling channel within the rotor shaft 410 and utilizing a first and second branch channel to guide the coolant to the upper cooling chamber 02 and lower cooling chamber 03 respectively, enables the coolant to synergistically cool the upper and lower ends of the motor rotor 420, the upper and lower ends of the stator windings, the corresponding inner walls of the motor housing 700, and the upper and lower bearings. This expands the cooling coverage of the internal liquid-cooled structure of the motor and reduces localized heat accumulation in areas such as the rotor ends, stator winding ends, and bearings. The three-dimensional meandering cooling channel within the stator core, the housing channel, and the permanent magnet cooling channel on the back of the permanent magnet further shorten the heat transfer path between the corresponding heat-generating parts and the coolant. In embodiments employing composite phase change materials, the phase change heat absorption can also buffer the thermal shock generated by transient overload, reducing temperature fluctuations in the corresponding motor components.

[0251] 2. This invention establishes a closed-loop coolant circulation system comprising a low-temperature coolant tank 01, a lower coolant tank 06, a high-temperature coolant tank 05, a circulating pump 07, a heat exchanger 14, and a filter 09. This system collects, exchanges heat with, and filters the coolant discharged from the top-drive liquid-cooled motor, and then re-feeds the treated coolant to the motor. This structure integrates the internal cooling path of the motor with the external coolant circulation loop, reducing the motor's dependence on internal forced airflow and ambient air density for cooling. The filter 09 also reduces the deposition or blockage of impurities in the motor's internal cooling channels. By improving the internal heat dissipation conditions of the motor, it also enhances the motor's ability to withstand continuous heat loads and provides a heat dissipation basis for the compact design of the top-drive motor and the improvement of torque and power density.

[0252] 3. This invention determines the operating state of the top drive based on the top drive operating condition signal and sets corresponding cooling modes for different operating states such as heavy-load drilling, variable-load operation, light-load operation, and standby. It utilizes a proportional-integral-derivative (PID) control algorithm to correct the target coolant flow rate based on the temperature deviation between the real-time coolant temperature and the target coolant temperature. Under variable-load operation, feedforward adjustment can also be performed based on expected torque changes or changes in motor input power, thereby adjusting the coolant flow rate before significant temperature changes and reducing control lag caused by thermal inertia. By adjusting the coolant flow rate, flow path, and heat exchange state according to different operating conditions, the operating output of the cooling system can be adapted to the actual cooling requirements, and unnecessary cooling output under light-load or standby conditions can be reduced.

[0253] 4. This invention monitors the operating status of the top-drive liquid-cooled motor and the coolant circulation loop by collecting data such as stator winding temperature, upper and lower bearing temperatures, coolant inlet and outlet temperatures, circuit pressure, circuit flow rate, and coolant tank level. It generates early warning information when abnormal flow, pressure, level, or heat exchange occurs. The relevant operating status and early warning information can be output to the driller's platform, providing a basis for the inspection and maintenance of the cooling system. In the dual-motor embodiment, the coolant flow rate of the two inlet branches can be adjusted separately according to the cooling needs of each motor. In the permanent magnet synchronous motor embodiment, a permanent magnet protection adjustment command can be generated based on the permanent magnet temperature, thereby improving the monitorability, controllability, and operational reliability of the top-drive motor liquid-cooled system.

[0254] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A top-drive liquid-cooled motor, comprising: The motor comprises a motor housing, a motor stator and a motor rotor disposed within the motor housing, a rotor shaft passing through the motor rotor and extending vertically, and an upper bearing housing and a lower bearing housing respectively disposed at the upper and lower ends of the rotor shaft. The motor stator includes a stator core and stator windings disposed on the stator core. The motor housing is provided with an upper cooling chamber and a lower cooling chamber. The upper end of the top-drive liquid-cooled motor is provided with a coolant inlet that communicates with the upper bearing chamber, and the lower end of the top-drive liquid-cooled motor is provided with a coolant outlet. The rotor shaft is a hollow structure, and a main cooling channel extending axially along the rotor shaft is formed inside the rotor shaft. The upper bearing chamber is connected to the upper end of the main cooling channel so that the coolant entering from the coolant inlet flows through the upper bearing chamber and then enters the main cooling channel. The rotor shaft is provided with a first flow divider channel and a second flow divider channel at different axial positions. The first flow divider channel and the second flow divider channel extend from the main cooling channel to the outer periphery of the rotor shaft. The first flow divider channel is connected to the upper cooling chamber, and the second flow divider channel is connected to the lower cooling chamber. The upper cooling chamber is provided corresponding to the upper end of the motor rotor and the upper end of the stator winding, so that the coolant flowing in through the first diversion channel cools the upper end of the motor rotor, the upper end of the stator winding, and the upper inner wall of the motor housing; the lower cooling chamber is provided corresponding to the lower end of the motor rotor and the lower end of the stator winding, so that the coolant flowing in through the second diversion channel cools the lower end of the motor rotor, the lower end of the stator winding, and the lower inner wall of the motor housing. The lower end of the main cooling channel is connected to the lower bearing chamber so that the coolant that continues to flow along the main cooling channel after being diverted by the first diversion channel and the second diversion channel enters the lower bearing chamber. The coolant flowing through the upper cooling chamber, the lower cooling chamber, and the lower bearing chamber is collected at the lower end of the top-drive liquid-cooled motor and discharged through the coolant outlet.

2. The top-drive liquid-cooled motor according to claim 1, characterized in that, The stator core is formed by stacking multiple stator laminations, each of which has a circumferential liquid passage. The multiple stator laminations are stacked in a staggered manner so that the multiple circumferential liquid passages are connected in sequence, forming a continuous three-dimensional meandering cooling channel inside the stator core. The stator core has grooves on its outside, and the motor housing has a housing flow channel that matches the grooves. The housing flow channel and the three-dimensional meandering cooling channel together constitute the cooling flow path of the motor stator.

3. The top-drive liquid-cooled motor according to claim 1, characterized in that, The top-drive liquid-cooled motor is an asynchronous motor, and the motor rotor includes a rotor core, rotor bars disposed in the rotor core, and rotor end rings disposed at both ends of the rotor bars. The first diversion channel includes a plurality of radial oblique holes disposed on the rotor shaft and located below the upper bearing chamber. The plurality of radial oblique holes are evenly distributed along the circumference of the rotor shaft and connect the main cooling channel with the upper cooling chamber. The second diversion channel includes a plurality of radial holes disposed on the rotor shaft and corresponding to the lower end of the rotor core, and the plurality of radial holes connect the main cooling channel and the lower cooling chamber; At least one location in the region where the rotor guide bar is located and the region where the rotor end ring is located is provided with a composite phase change material for absorbing transient heat.

4. The top-drive liquid-cooled motor according to claim 1, characterized in that, The top-drive liquid-cooled motor is a permanent magnet synchronous motor, and the motor rotor includes a rotor core and permanent magnets disposed in permanent magnet slots in the rotor core. The rotor core is provided with multiple sets of permanent magnet cooling channels extending axially along the rotor shaft. The permanent magnet cooling channels are arranged parallel to the permanent magnet slots and extend along the back of the corresponding permanent magnets. The multiple sets of permanent magnet cooling channels are respectively connected to the main cooling channel through radial branch pipes, so that the coolant in the main cooling channel enters the permanent magnet cooling channel through the radial branch pipes and flows along the back of the corresponding permanent magnet; The permanent magnet has a composite phase change material in the interpole gap for absorbing transient heat.

5. The top-drive liquid-cooled motor according to claim 4, characterized in that, The motor housing is provided with an inner cooling channel and an outer cooling channel located outside the inner cooling channel. The inner cooling channel is arranged along the outer peripheral surface of the stator core and is in contact with the outer peripheral surface of the stator core. The outer cooling channel is used for the circulation of coolant.

6. A liquid cooling system for a top drive motor, characterized in that, Includes the top-drive liquid-cooled motor, coolant circulation loop, data acquisition layer, intelligent control and decision-making layer, and execution and regulation layer as described in any one of claims 1 to 5; The coolant circulation loop includes a low-temperature coolant tank, a lower coolant tank, a high-temperature coolant tank, a circulation pump, a heat exchanger, a filter, and connecting pipes. The low-temperature coolant tank is connected to the coolant inlet of the top-drive liquid-cooled motor, the coolant outlet of the top-drive liquid-cooled motor is connected to the lower coolant tank, the lower coolant tank is connected to the high-temperature coolant tank, and the high-temperature coolant tank is connected to the low-temperature coolant tank via the heat exchanger and the filter, thereby forming a closed loop. The circulation pump is installed in the coolant circulation loop to drive the coolant circulation. The data acquisition layer is used to acquire motor status data of the top-drive liquid-cooled motor and loop status data of the coolant circulation loop, and to receive top-drive operating condition signals. The motor status data includes stator winding temperature data, upper bearing temperature data, and lower bearing temperature data. The loop status data includes coolant temperature data at the coolant inlet and outlet, pressure data and flow data in the coolant circulation loop, and liquid level data of the low-temperature coolant tank and the high-temperature coolant tank. The intelligent control and decision-making layer is communicatively connected to the data acquisition layer and the execution and regulation layer, respectively, and is used to generate cooling regulation commands based on the motor status data, the circuit status data and the top drive condition signal; The execution and regulation layer includes a flow and direction control unit and a power and heat exchange unit. The flow and direction control unit is located in the coolant circulation loop and is used to adjust the flow rate and flow path of the coolant according to the cooling regulation command. The power and heat exchange unit includes the circulation pump and the heat exchanger and is used to control the operation of the circulation pump according to the cooling regulation command and to regulate the coolant temperature through the heat exchanger.

7. The top drive motor liquid cooling system according to claim 6, characterized in that, The power and heat exchange unit also includes a refrigerant circulation loop, which includes a compressor, a condenser, a throttle valve and the heat exchanger connected by a refrigerant pipeline. The refrigerant circulation loop is used to cool the coolant in the coolant circulation loop through the heat exchanger. The intelligent control and decision-making layer is also used to determine whether the preset cooling start-up conditions are met based on the motor status data, the circuit status data and the top drive condition signal, and to generate a cooling start-stop command based on the determination result. The power and heat exchange unit is also used to control the compressor to start and stop according to the refrigeration start / stop command.

8. The top drive motor liquid cooling system according to claim 6, characterized in that, The flow and direction control unit includes a proportional regulating valve and a multi-way reversing valve. Both the proportional regulating valve and the multi-way reversing valve are disposed in the coolant circulation loop. The proportional regulating valve is used to regulate the coolant flow according to the cooling regulation command. The multi-way reversing valve is used to switch between a bypass circulation path where the coolant bypasses the heat exchanger and a heat exchange circulation path where the coolant flows through the heat exchanger, according to the cooling regulation command. The power and heat exchange unit also includes a variable frequency drive connected to the circulating pump drive, the variable frequency drive being used to adjust the speed of the circulating pump according to the cooling adjustment command.

9. The top drive motor liquid cooling system according to claim 6, characterized in that, The data acquisition layer includes a temperature sensor group, a pressure sensor group, a flow sensor group, a liquid level sensor group, and a top drive operating condition signal interface. The temperature sensor group includes multiple temperature sensors respectively corresponding to the stator winding, the bearing in the upper bearing chamber, the bearing in the lower bearing chamber, the coolant inlet, the coolant outlet, and the environment where the top-drive liquid-cooled motor is located, for detecting the stator winding temperature, the upper bearing temperature, the lower bearing temperature, the coolant inlet temperature, the coolant outlet temperature, and the ambient temperature. The pressure sensor group includes multiple pressure sensors respectively installed at the outlet of the circulating pump, the main pipeline of the coolant circulation loop, and the inlet branch connected to the coolant inlet, for detecting the coolant pressure at corresponding locations. The flow sensor group includes multiple flow sensors respectively disposed on the main pipeline and the inlet branch, for detecting the flow rate of coolant in the main pipeline and the inlet branch respectively; The liquid level sensor group includes liquid level sensors respectively disposed in the low-temperature coolant tank and the high-temperature coolant tank, for detecting the coolant level in the low-temperature coolant tank and the high-temperature coolant tank respectively; The top drive operating condition signal interface is communicatively connected to the top drive main control system and is used to receive the top drive operating condition signals sent by the top drive main control system. The top drive operating condition signals include motor speed signals, torque current signals, motor input power signals, and operating condition status signals sent from the driller's platform to the top drive main control system.

10. The top drive motor liquid cooling system according to claim 9, characterized in that, The intelligent control and decision-making layer includes a signal preprocessing and transmission unit, a programmable logic controller, and a human-machine interaction unit. The programmable logic controller includes a core control unit and a status diagnosis unit. The signal preprocessing and transmission unit is connected to the temperature sensor group, the pressure sensor group, the flow sensor group, the liquid level sensor group and the programmable logic controller respectively. It is used to perform signal conditioning on the raw sensor signals output by each sensor group and send the signal-conditioned sensor signals to the programmable logic controller through an anti-interference communication link. The top drive condition signal interface is connected to the programmable logic controller and is used to send the top drive condition signal to the programmable logic controller. The core control unit is used to run a feedback control program, perform composite adjustment based on top drive condition feedforward and real-time temperature feedback according to the signal-conditioned sensor signal and the top drive condition signal, and generate the cooling adjustment command. The status diagnosis unit is used to determine the operating status of the top drive motor liquid cooling system based on the sensor signal after signal conditioning, and to generate early warning information when the operating status is abnormal. The human-machine interface unit is connected to the programmable logic controller and is used to output the operating status of the top drive motor liquid cooling system and the early warning information to the driller's platform.

11. The top drive motor liquid cooling system according to claim 8, characterized in that, The number of top-drive liquid-cooled motors is two, both of which are asynchronous motors. The coolant inlets of the two top-drive liquid-cooled motors are connected to the low-temperature coolant tank through parallel inlet branches, and the coolant outlets of the two top-drive liquid-cooled motors are connected to the lower coolant tank. The proportional control valve includes a total proportional control valve disposed on the main circuit of the coolant circulation loop and two branch proportional control valves respectively disposed on the two inlet branches; The data acquisition layer includes a total flow sensor disposed on the main circuit, two branch flow sensors disposed on the two inlet branches respectively, and two branch pressure sensors disposed on the two inlet branches respectively. The total flow sensor is used to collect the total flow data in the main circuit, the two branch flow sensors are used to collect the branch flow data of the two inlet branches respectively, and the two branch pressure sensors are used to collect the branch pressure data of the two inlet branches respectively. The intelligent control and decision-making layer is also used to generate a total flow adjustment command and branch flow adjustment commands corresponding to the two liquid inlet branches based on the motor status data of the two top drive liquid-cooled motors, the total flow data, the branch flow data and branch pressure data of the two liquid inlet branches, and the top drive operating condition signal. The execution and regulation layer is also used to adjust the opening degree of the total proportional regulating valve and the rotation speed of the circulating pump according to the total flow regulation command, and to adjust the opening degree of the two branch proportional regulating valves respectively according to the two branch flow regulation commands.

12. The top drive motor liquid cooling system according to claim 6, characterized in that, The top-drive liquid-cooled motor is a permanent magnet synchronous motor, and the motor rotor includes a rotor core and permanent magnets disposed in permanent magnet slots in the rotor core. The data acquisition layer also includes a wireless temperature sensor embedded inside the motor rotor. The wireless temperature sensor is used to detect the temperature of the permanent magnet to obtain permanent magnet temperature data. The intelligent control and decision-making layer is also used to generate permanent magnet protection adjustment commands based on the permanent magnet temperature data and the stator winding temperature data, combined with the circuit status data and the top drive condition signal. The execution and regulation layer is also used to regulate the coolant flow rate and coolant temperature according to the permanent magnet protection regulation command.

13. A feedback control method, characterized in that, The method, applied to the top drive motor liquid cooling system according to any one of claims 6 to 12, comprises: Acquire the top drive operating condition signal and determine the top drive operating status based on the top drive operating condition signal; The corresponding cooling mode is determined based on the top drive working state, and the target temperature of the coolant, the reference flow rate of the coolant, and the initial control parameters corresponding to the cooling mode are obtained. The initial control parameters include the initial proportional coefficient, the initial integral coefficient, and the initial derivative coefficient. The real-time temperature of the coolant collected by the data acquisition layer is obtained, and the temperature deviation is determined based on the real-time temperature of the coolant and the target temperature of the coolant. Based on the initial control parameters and the temperature deviation, a proportional-integral-derivative control algorithm is used to calculate the feedback flow correction, and the target flow rate of the coolant is determined based on the coolant reference flow rate and the feedback flow correction. Generate flow regulation parameters to make the coolant flow rate reach the target flow rate of the coolant, and determine heat exchange control parameters according to the cooling mode, and generate a cooling regulation command including the flow regulation parameters and the heat exchange control parameters; The cooling adjustment command is sent to the execution and regulation layer, so that the execution and regulation layer adjusts the coolant flow rate according to the flow rate adjustment parameter, and controls the heat exchanger to exchange heat with the coolant according to the heat exchange control parameter, so as to regulate the coolant temperature.

14. The feedback control method according to claim 13, characterized in that, The top drive working states include top drive heavy-load drilling state, top drive variable load operation state, top drive light-load operation state, and top drive standby state. The top drive heavy-load drilling state corresponds to the heavy-load cooling mode, the top drive variable-load operation state corresponds to the variable-load cooling mode, the top drive light-load operation state corresponds to the light-load cooling mode, and the top drive standby state corresponds to the standby cooling mode. The heavy-load cooling mode, the variable-load cooling mode, the light-load cooling mode, and the standby cooling mode are each equipped with a corresponding preset target coolant temperature, preset coolant reference flow rate, and preset initial control parameters.

15. The feedback control method according to claim 14, characterized in that, When the top drive is in the top drive variable load operation state, determining the target coolant flow rate based on the coolant reference flow rate and the feedback flow correction includes: Obtain load change parameters to characterize expected load changes, the load change parameters including at least one of torque change parameters and motor input power change parameters; The feedforward flow correction amount is determined based on the load change parameters; The target flow rate of the coolant is determined based on the coolant reference flow rate, the feedback flow correction, and the feedforward flow correction.

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