Three-phase permanent magnet synchronous motor

Abstract

The invention relates to the technical field of motors, in particular to a three-phase permanent magnet synchronous motor which is composed of a motor shell, a stator and a rotor and further comprises a cooling mechanism, the cooling mechanism is used for cooling the interior of the motor, and the cooling mechanism comprises an annular cooling cylinder fixedly arranged on one side of the motor shell. The stator and the rotor can be efficiently cooled through the annular cooling cylinder and the spiral liquid cooling pipe, and the design of the heat conduction assembly and the cooling assembly ensures that the temperature of each part in the motor is uniformly distributed, so that potential problems caused by local overheating are avoided. The uniform cooling helps to maintain the performance consistency and reliability of the motor, and the motor drives the first draft fan and the second draft fan to enable the cooled air to circulate in the motor shell and the rotor while starting, thereby improving the cooling efficiency, and enabling the cooling effect to be more remarkable.

Description

Technical Field

[0001] The present invention relates to the technical field of electric motors, and in particular to a three-phase permanent magnet synchronous motor. Background Art

[0002] The three-phase permanent magnet synchronous motor (PMSM) is an electric motor that uses built-in permanent magnets to generate a rotating magnetic field through three-phase alternating current to drive the rotor to rotate synchronously. Its main advantages include high efficiency, high power factor and low maintenance requirements because it does not rely on brushes and slip rings. The control of the motor usually adopts vector control or direct torque control technology to achieve precise speed and torque control. It is widely used in industrial automation, robotics, electric vehicles and other fields.

[0003] When existing electric motors are running, local high temperatures will be generated due to unstable power supply and uneven cooling. If local high temperatures occur in the stator part, it may lead to reduced efficiency of the motor and even shorten the service life of the motor. The existing motor cooling usually cools the inside of the motor as a whole, and cannot perform targeted cooling of the locations where local high temperatures occur on the stator while cooling the inside. For example, a balanced cooling motor proposed in application number CN202111208646.5 can only cool the inside of the motor as a whole, and cannot dynamically adapt to internal heat changes according to the motor. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, the present invention provides a three-phase permanent magnet synchronous motor, which can effectively solve the problem that the prior art can only cool the entire interior of the motor but cannot perform targeted cooling at the locations where high temperatures occur locally on the stator.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: The present invention provides a three-phase permanent magnet synchronous motor, which consists of a motor housing, a stator, and a rotor. The motor also includes: A cooling mechanism, which is used to cool the inside of the motor. The cooling mechanism includes an annular cooling cylinder fixedly arranged on one side of the motor housing, a first spiral liquid cooling tube for cooling is arranged in the annular cooling tube, a second spiral liquid cooling tube is arranged outside the first spiral liquid cooling tube, a temperature measuring interlayer is formed between the first spiral liquid cooling tube and the second spiral liquid cooling tube, a heat conducting component is arranged in the temperature measuring interlayer, and the heat conducting component is used to conduct the heat generated by the stator due to work to the first spiral liquid cooling tube. The cooling mechanism also includes a cooling component, which is arranged in the motor housing and is used to cool the rotor.

[0006] Preferably, the inner wall of the motor housing is fixedly connected to the stator, the inner center of the motor housing is rotatably connected to the outer wall of the rotor, and the rotor has a centrally built-in rotating shaft.

[0007] Preferably, the cooling mechanism also includes an annular refrigeration fin embedded in the outer peripheral wall of the annular cooling cylinder, the cooling end of the annular refrigeration fin faces inward and the heating end faces outward, a cooling medium is arranged in the annular cooling cylinder, a first water pump is fixedly connected to the outer peripheral wall of the annular cooling cylinder, the water pumping end of the first water pump is connected to the cooling cylinder, the water outlet end of the first water pump is fixedly connected to a drain pipe, the other end of the drain pipe passes through the motor housing and is connected to the first spiral liquid cooling pipe, the second spiral liquid cooling pipe is fixedly wound around the outer wall of the stator, and both ends of the first spiral liquid cooling pipe and the second spiral liquid cooling pipe are commonly and air-tightly fixedly connected to an annular support block.

[0008] Preferably, the heat conducting component includes a heat conducting ring slidably mounted on the outer wall of the first spiral liquid cooling tube, a temperature measuring ring for monitoring the stator temperature is embedded in the outer surface of the heat conducting ring, and the heat conducting ring and the temperature measuring ring are both slidably connected to the inner wall of the second spiral liquid cooling tube, the outer peripheral wall of the motor housing is fixedly connected to a second water pump, the water pumping end of the second water pump is fixedly connected to a water supply pipe, the other end of the water supply pipe passes through one of the annular support blocks and extends into the temperature measuring interlayer, the water pumping end of the second water pump is connected to the inside of the annular cooling tube, the temperature measuring ring can be moved by liquid push in the temperature measuring interlayer, and the outer wall of the other annular support block is fixedly connected to a return pipe, and the other end of the return pipe is connected to the inside of the annular cooling tube, the second water pump, the temperature measuring ring and the first water pump are electrically connected to a PLC controller to form a refrigeration circuit, and a plurality of water channels are opened in the heat conducting ring.

[0009] Preferably, the water outlet end of the first spiral liquid cooling tube is fixedly connected to the first connecting tube, the other end of the first connecting tube passes through the motor housing and is fixedly connected to the third spiral liquid cooling tube, the outer wall of the third spiral liquid cooling tube is fixedly connected to the outer wall of the motor housing, the other end of the third spiral liquid cooling tube is fixedly connected to the second connecting tube, and the other end of the second connecting tube is connected to the interior of the annular cooling cylinder.

[0010] Preferably, the cooling assembly includes a plurality of connecting rods fixedly connected to the inner wall of the annular cooling cylinder, the other ends of the plurality of connecting rods are commonly fixedly connected to a blocking block, a plurality of air inlets are provided on the outer wall of the motor housing on one side close to the annular cooling cylinder, and a plurality of air outlets are provided on the outer wall of the motor housing on the side away from the annular cooling cylinder.

[0011] Preferably, an annular groove is provided on the inner wall of the rotating shaft, and the annular groove separates one end of the rotating shaft into an inner shaft and an outer tube. A rotating rod is fixedly connected to one end of the rotating shaft close to the annular cooling tube, and a first exhaust fan is fixedly connected to the other end of the rotating rod, and the rotating rod passes through the blocking block and is rotatably connected thereto, a second exhaust fan is fixedly connected to the outer wall of the inner shaft of the rotating shaft, and an exhaust port connected to the annular groove is provided on the end of the rotating rod away from the outside of the annular cooling tube.

[0012] Preferably, a wind hood is fixedly mounted on a side of the annular cooling cylinder away from the air outlet, and filter screens are provided in both the air outlet and the air inlet.

[0013] Compared with the known prior art, the technical solution provided by the present invention has the following beneficial effects: The stator and rotor can be cooled efficiently by the annular cooling tube and spiral liquid cooling tube. The design of the heat conduction component and the cooling component ensures the uniform temperature distribution of the internal components of the motor, thus avoiding potential problems caused by local overheating. This uniform cooling helps to maintain the performance consistency and reliability of the motor, and the motor drives the first and second exhaust fans at the same time when it is started, so that the cooled air circulates in the motor housing and the rotor, thereby improving the cooling efficiency and making the cooling effect more significant. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0015] Figure 1 The three-dimensional structure of the present invention is shown in FIG. Figure 1 ; Figure 2 The three-dimensional structure of the present invention is shown in FIG. Figure 2 ; Figure 3 It is a schematic diagram of a three-dimensional structure of a three-dimensional part section of the present invention; Figure 4 It is a schematic diagram of a partial three-dimensional cross-sectional structure of the present invention; Figure 5 Schematic diagram of the three-dimensional connection of the internal pipeline of the present invention Figure 1 ; Figure 6 Schematic diagram of the three-dimensional connection of the internal pipeline of the present invention Figure 2 ; Figure 7 It is a schematic diagram of the cross-sectional plan structure of the pipeline portion of the present invention.

[0016] 1. Motor housing; 2. Stator; 3. Rotor; 31. Rotating shaft; 4. Cooling mechanism; 41. Annular cooling cylinder; 42. First spiral liquid cooling tube; 43. Second spiral liquid cooling tube; 44. Heat conducting assembly; 441. Heat conducting ring; 442. Temperature measuring ring; 443. Second water pump; 444. Water supply pipe; 445. First connecting pipe; 431. Third spiral liquid cooling tube; 447. Second connecting pipe; 448. Return pipe; 449. Water channel; 45. Cooling assembly; 451. Connecting rod; 452. Blocking block; 453. Air inlet; 454. Air outlet; 455. Annular groove; 456. First exhaust fan; 457. Second exhaust fan; 458. Exhaust port; 459. Rotating rod; 46. Drain pipe; 47. Annular cooling plate; 48. First water pump; 49. Annular support block. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] The present invention will be further described below in conjunction with the embodiments.

[0019] Example: Refer to Figures 1 to 7 A three-phase permanent magnet synchronous motor, the motor is composed of a motor housing 1, a stator 2, and a rotor 3, and the motor also includes: A cooling mechanism 4 is used to cool the inside of the motor. The cooling mechanism 4 includes an annular cooling tube 41 fixedly arranged on one side of the motor housing 1. A first spiral liquid cooling tube 42 for cooling is arranged in the annular cooling tube 41. A second spiral liquid cooling tube 43 is arranged outside the first spiral liquid cooling tube 42. A temperature measuring interlayer is formed between the first spiral liquid cooling tube 42 and the second spiral liquid cooling tube 43. A heat conducting component 44 is arranged in the temperature measuring interlayer. The heat conducting component 44 is used to conduct the heat generated by the stator 2 due to work to the first spiral liquid cooling tube 42. The cooling mechanism 4 also includes a cooling component 45. The cooling component 45 is arranged in the motor housing 1. The cooling component 45 is used to cool the rotor 3. The first spiral liquid cooling tube 42 and the second spiral liquid cooling tube 43 are both made of materials with good thermal conductivity. The double-layer liquid cooling tube can prevent the single-layer liquid cooling tube from directly contacting the heat source, and can prevent the thermal stress caused by direct contact with the heat source with drastic temperature changes, causing the condenser to deform or rupture.

[0020] The inner wall of the motor housing 1 is fixedly connected to the stator 2, and the inner center of the motor housing 1 is rotatably connected to the outer wall of the rotor 3, and the rotor 3 has a centrally built-in rotating shaft 31; The motor converts electrical energy into mechanical energy through the interaction between the rotating magnetic field generated by the stator 2 and the current in the rotor 3. When the stator 2 winding is energized, the generated magnetic field exerts torque on the rotor 3, driving it to rotate, thereby driving the shaft 31 to rotate.

[0021] The stator is cooled by the following specific structure, refer to Figures 2 to 4 The cooling mechanism 4 also includes an annular refrigeration fin 47 embedded in the outer peripheral wall of the annular cooling tube 41, the cooling end of the annular refrigeration fin 47 faces inward and the heating end faces outward, a cooling medium (such as water or oil) is arranged in the annular cooling tube 41, a first water pump 48 is fixedly connected to the outer peripheral wall of the annular cooling tube 41, a water pumping end of the first water pump 48 is connected to the cooling tube, a water outlet end of the first water pump 48 is fixedly connected to a drain pipe 46, the other end of the drain pipe 46 passes through the motor housing 1 and is connected to the first spiral liquid cooling tube 42, the outer wall of the second spiral liquid cooling tube 43 is fixedly wound around the outer wall of the stator 2, both ends of the first spiral liquid cooling tube 42 and the second spiral liquid cooling tube 43 are commonly and airtightly fixedly connected to an annular support block 49, and the annular support block 49 is used to maintain the relative position of the first spiral liquid cooling tube 42 and the second spiral liquid cooling tube 43.

[0022] The following structure is used to reduce the local high temperature of the stator. Figure 2 , Figure 3 , Figure 7 , Figure 6 The heat conducting assembly 44 comprises a heat conducting ring 441 which is slidably mounted on the outer wall of the first spiral liquid cooling tube 42. A temperature measuring ring 442 for monitoring the stator temperature is embedded on the outer surface of the heat conducting ring 441. The heat conducting ring 441 and the temperature measuring ring 442 are both slidably connected to the inner wall of the second spiral liquid cooling tube 43. A second water pump 443 is fixedly connected to the outer peripheral wall of the motor housing 1. A water supply pipe 444 is fixedly connected to the water pumping end of the second water pump 443. The other end of the water supply pipe 444 passes through one of the annular support blocks 49 and extends Extending into the temperature measuring interlayer, the water pumping end of the second water pump 443 is connected to the inside of the annular cooling tube 41, the temperature measuring ring 442 can be moved by liquid in the temperature measuring interlayer, and the outer wall of another annular support block 49 is fixedly connected with a return pipe 448, and the other end of the return pipe 448 is connected to the inside of the annular cooling tube 41, the second water pump 443, the temperature measuring ring 442, and the first water pump 48 are electrically connected to the PLC controller to form a refrigeration circuit, and a plurality of water channels 449 are opened in the heat conducting ring 441.

[0023] The water outlet end of the first spiral liquid cooling pipe 42 is fixedly connected with a first connecting pipe 445, the other end of the first connecting pipe 445 penetrates the motor housing 1 and is fixedly connected with a third spiral liquid cooling pipe 431, the outer wall of the third spiral liquid cooling pipe 431 is fixedly connected with the outer wall of the motor housing 1, the other end of the third spiral liquid cooling pipe 431 is fixedly connected with a second connecting pipe 447, and the other end of the second connecting pipe 447 is connected with the inside of the annular cooling cylinder 41; The cooling medium in the first spiral liquid cooling tube 42 will flow along the direction of the first condenser until it moves to the first connecting tube 445, and then flow to the third spiral liquid cooling tube 431. The cooling medium in the third spiral liquid cooling tube 431 is then discharged into the annular cooling tube 41 through the second connecting tube 447 for cooling again, thereby circulating to cool the cooling medium.

[0024] The following settings are used to cool the rotor and the interior of the rotor. Figures 1 to 3 The cooling component 45 includes a plurality of connecting rods 451 fixedly connected to the inner ring wall of the annular cooling cylinder 41, and the other ends of the plurality of connecting rods 451 are commonly fixedly connected to a blocking block 452. A plurality of air inlets 453 are provided on the outer wall of the motor housing 1 on one side close to the annular cooling cylinder 41, and a plurality of air outlets 454 are provided on the outer wall of the motor housing 1 on one side away from the annular cooling cylinder 41. The blocking block 452 can allow air to pass between the blocking block 452 and the annular cooling cylinder 41 to ensure the cooling effect of the air, and the blocking block 452 does not contact the annular groove 455, so that air can enter the annular groove 455.

[0025] An annular groove 455 is provided on the inner wall of the rotating shaft 31, and the annular groove 455 separates one end of the rotating shaft 31 into an inner shaft and an outer tube. A rotating rod 459 is fixedly connected to one end of the rotating shaft 31 close to the annular cooling tube 41, and a first exhaust fan 456 is fixedly connected to the other end of the rotating rod 459. The rotating rod 459 penetrates the blocking block 452 and is rotatably connected thereto. A second exhaust fan 457 is fixedly connected to the outer wall of the inner shaft of the rotating shaft 31, and an exhaust port 458 connected to the annular groove 455 is provided on the end of the rotating rod 459 away from the outside of the annular cooling tube 41.

[0026] A wind hood is fixedly installed on one side of the annular cooling cylinder 41 away from the exhaust port 458, and filter screens are provided in the exhaust port 458 and the air inlet 453. The wind hood can prevent larger impurities from entering the motor, and the filter screen can prevent dust from entering the motor.

[0027] The working principle of the present invention is as follows: While the motor is running, the temperature measuring ring 442, the first water pump 48, the second water pump 443, and the annular refrigeration sheet 47 are started, and the cooling medium in the annular cooling tube 41 is continuously cooled by the annular refrigeration sheet 47, and the condensed cooling medium is pumped out by the first water pump 48 and discharged into the first spiral liquid cooling tube 42, and at the same time, the condensed water in the annular cooling tube 41 is pumped out by the second water pump 443, and then discharged into the space between the first spiral liquid cooling tube 42 and the second spiral liquid cooling tube 43, and the condensed water after cooling is discharged, and the heat conductive ring 441 is pushed to move along the direction of the first spiral liquid cooling tube 42 by the condensed water after cooling, and then the heat conductive ring 441 is pushed to move along the direction of the first spiral liquid cooling tube 42, and then the heat conductive ring 44 1 conducts the temperature of the stator 2 to the outer wall of the first spiral liquid cooling tube 42 for cooling. The position where the heat-conducting ring 441 has not moved can also be cooled by the conduction of the condensed water after cooling. When the heat-conducting ring 441 drives the temperature measuring ring 442 to detect that the temperature of the stator 2 at a certain position is overheated, an electrical signal is sent to the PLC controller through the temperature measuring ring 442, and the second water pump 443 is controlled by the PLC controller to slow down the efficiency of water injection into the interlayer, so that the condensed water after cooling cannot push the heat-conducting ring 441 to continue to move, so that the heat-conducting ring 441 stays at the position where the temperature of the stator 2 is higher to continue to cool down, but the condensed water will continue to slowly pass through the water channel 449. Flow, so that the condensed water moves slowly, continue to keep cooling the rest of the positions, and control the first water pump 48 to improve the working efficiency, so that the cooling medium flows quickly to increase the cooling speed, until the temperature detected by the temperature measuring ring 442 returns to normal, (wherein the stator suitable temperature range set by pre-test is T1-T2, the optimal working temperature is T3=(T1+T2) / 2, when the real-time temperature value (set as T4) is greater than T2, stop the air push, and increase the cooling power until the monitored temperature is T3), then control the second water pump 443 and the first water pump 48 to resume normal operation through the PLC controller, wherein the wind of the second water pump 443 The time for conversion (i.e., driving direction) is pre-tested. For example, the one-way time of the air-driven heat-conducting ring 441 moving in the temperature measuring interlayer is t, and t is obtained in advance. The test factors are the length of the temperature measuring interlayer and the air pressure thrust. If the heat-conducting ring 441 stays at a position where the local temperature of the stator is higher during this period, it is necessary to add a stay cooling time (i.e., the downtime of the second water pump 443) of t1. Therefore, the one-way time of the air-driven heat-conducting ring 441 is t+t1, and the one-way time t obtained from the test is input into the PLC controller, and then the PLC controller records the stay time t1 in real time, and then the PLC controller can increase t1 based on t.

[0028] The cooling medium in the first spiral liquid cooling tube 42 will flow along the direction of the first spiral liquid cooling tube 42 until it moves to the first connecting tube 445, and then flow into the third spiral liquid cooling tube 431, and then the cooling medium in the third spiral liquid cooling tube 431 will be discharged into the annular cooling cylinder 41 through the second connecting tube 447 for cooling again, thereby circulating to cool the cooling medium.

[0029] The rotating magnetic field generated by the stator 2 of the motor interacts with the current in the rotor 3 to convert electrical energy into mechanical energy. When the stator 2 winding is energized, the magnetic field generated applies torque to the rotor 3, driving it to rotate, thereby driving the rotating shaft 31 to rotate, and then the second exhaust fan 457 to rotate, and the rotating shaft 31 drives the rotating rod 459 to rotate, and the rotating rod 459 further drives the first exhaust fan 456 to rotate, and then the outside air is drawn into the through hole in the middle of the annular cooling cylinder 41 through the first exhaust fan 456, and then the cold air emitted from the through hole in the middle of the annular cooling cylinder 41 is used to cool the air, and then the cooled air enters the interior of the motor housing 1 through the air inlet 453, further cools the stator 2 and rotor 3 inside, and then is discharged through the exhaust port 458. At the same time, a part of the cold air is drawn into the annular groove 455 by the second exhaust fan 457, thereby cooling the inside of the rotor 3, and then the air is discharged through the exhaust port 458.

[0030] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A three-phase permanent magnet synchronous motor, the motor comprising a motor housing (1), a stator (2), and a rotor (3), characterized in that: The motor also includes: A cooling mechanism (4), the cooling mechanism (4) is used to cool the inside of the motor, the cooling mechanism (4) comprises an annular cooling tube (41) fixedly arranged on one side of the motor housing (1), a first spiral liquid cooling tube (42) for cooling is arranged inside the annular cooling tube (41), a second spiral liquid cooling tube (43) is arranged outside the first spiral liquid cooling tube (42), a temperature measuring interlayer is formed between the first spiral liquid cooling tube (42) and the second spiral liquid cooling tube (43), a heat conducting component (44) is arranged in the temperature measuring interlayer, the heat conducting component (44) is used to conduct heat generated by the stator (2) during operation to the first spiral liquid cooling tube (42), the cooling mechanism (4) further comprises a cooling component (45), the cooling component (45) is arranged inside the motor housing (1), the cooling component (45) is used to cool the rotor (3).

2. A three-phase permanent magnet synchronous motor according to claim 1, characterized in that: The inner wall of the motor housing (1) is fixedly connected to the stator (2), the inner center of the motor housing (1) is rotatably connected to the outer wall of the rotor (3), and the rotor (3) has a centrally built-in rotating shaft (31).

3. A three-phase permanent magnet synchronous motor according to claim 2, characterized in that: The cooling mechanism (4) further comprises an annular refrigeration fin (47) embedded in the outer peripheral wall of the annular cooling tube (41), the cooling end of the annular refrigeration fin (47) facing inward and the heating end facing outward, a cooling medium is arranged in the annular cooling tube (41), a first water pump (48) is fixedly connected to the outer peripheral wall of the annular cooling tube (41), the water pumping end of the first water pump (48) is connected to the cooling tube, the water outlet end of the first water pump (48) is fixedly connected to a drainage pipe (46), the other end of the drainage pipe (46) passes through the motor housing (1) and is connected to the first spiral liquid cooling pipe (42), the second spiral liquid cooling pipe (43) is fixedly wound around the outer wall of the stator (2), and both ends of the first spiral liquid cooling pipe (42) and the second spiral liquid cooling pipe (43) are commonly and airtightly fixedly connected to an annular support block (49).

4. A three-phase permanent magnet synchronous motor according to claim 2, characterized in that: The heat-conducting component (44) comprises a heat-conducting ring (441) slidably mounted on the outer wall of the first spiral liquid-cooling tube (42); a temperature measuring ring (442) for monitoring the stator temperature is embedded in the outer surface of the heat-conducting ring (441); and the heat-conducting ring (441) and the temperature measuring ring (442) are both slidably connected to the inner wall of the second spiral liquid-cooling tube (43); a second water pump (443) is fixedly connected to the outer peripheral wall of the motor housing (1); a water pumping end of the second water pump (443) is fixedly connected to a water supply pipe (444); and the other end of the water supply pipe (444) passes through one of the annular support blocks (49). ) and extends into the temperature measuring interlayer, the water pumping end of the second water pump (443) is connected to the inside of the annular cooling tube (41), the temperature measuring ring (442) can be pushed by liquid in the temperature measuring interlayer, and the outer wall of another annular support block (49) is fixedly connected to a return pipe (448), and the other end of the return pipe (448) is connected to the inside of the annular cooling tube (41), the second water pump (443), the temperature measuring ring (442), and the first water pump (48) are electrically connected to a PLC controller to form a refrigeration circuit, and a plurality of water channels (449) are opened in the heat conducting ring (441).

5. A three-phase permanent magnet synchronous motor according to claim 4, characterized in that: The water outlet end of the first spiral liquid cooling tube (42) is fixedly connected to a first connecting tube (445); the other end of the first connecting tube (445) passes through the motor housing (1) and is fixedly connected to a third spiral liquid cooling tube (431); the outer wall of the third spiral liquid cooling tube (431) is fixedly connected to the outer wall of the motor housing (1); the other end of the third spiral liquid cooling tube (431) is fixedly connected to a second connecting tube (447); the other end of the second connecting tube (447) is connected to the interior of the annular cooling tube (41).

6. A three-phase permanent magnet synchronous motor according to claim 4, characterized in that: The cooling assembly (45) comprises a plurality of connecting rods (451) fixedly connected to the inner ring wall of the annular cooling cylinder (41); the other ends of the plurality of connecting rods (451) are commonly fixedly connected to a blocking block (452); a plurality of air inlets (453) are provided on the outer wall of the motor housing (1) on a side close to the annular cooling cylinder (41); and a plurality of air outlets (454) are provided on the outer wall of the motor housing (1) on a side away from the annular cooling cylinder (41).

7. A three-phase permanent magnet synchronous motor according to claim 6, characterized in that: An annular groove (455) is provided on the inner wall of the rotating shaft (31), and the annular groove (455) separates one end of the rotating shaft (31) into an inner shaft and an outer tube. An end of the rotating shaft (31) close to the annular cooling tube (41) is fixedly connected to a rotating rod (459), and the other end of the rotating rod (459) is fixedly connected to a first exhaust fan (456), and the rotating rod (459) passes through the blocking block (452) and is rotatably connected thereto. A second exhaust fan (457) is fixedly connected to the outer wall of the inner shaft of the rotating shaft (31), and an exhaust port (458) connected to the annular groove (455) is provided on one end of the rotating rod (459) away from the outside of the annular cooling tube (41).

8. A three-phase permanent magnet synchronous motor according to claim 7, characterized in that: A wind hood is fixedly mounted on one side of the annular cooling cylinder (41) away from the air outlet (458), and filter screens are provided in both the air outlet (458) and the air inlet (453).

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