Sensorless permanent magnet synchronous motor

Abstract

A sensorless permanent magnet synchronous motor comprises a shell assembly, a mounting cavity used for mounting a rotor and a stator is formed in the shell assembly, the shell assembly comprises a shell body with openings in the two ends, the shell body comprises an inner shell and an outer shell, the outer shell is arranged outside the inner shell in a sleeving mode, and the inner shell and the outer shell are arranged in a sleeving mode. Two ends of the outer shell are hermetically connected with two ends of the inner shell, so that a cavity is formed between the outer shell and the inner shell; according to the utility model, oil cooling heat radiation and water cooling heat radiation which are mutually independent are integrated, the heat radiation efficiency and the heat radiation effect of the permanent magnet synchronous motor are obviously optimized, and the operation stability of the motor is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of motors, in particular to a sensorless permanent magnet synchronous motor. Background Technique

[0002] In order to overcome the defects brought by using mechanical sensors to the system, sensorless control technology has become a research hotspot in the field of motor control technology. According to the estimation effect of the sensorless PMSM rotor position self-detection method in different speed ranges, all sensorless control methods can be divided into two categories: the first category is applicable to medium and high speeds; the second category is applicable to zero speed or extremely low speeds. Combining the two categories of control methods to form a composite control method can realize the speed regulation of the motor within the full speed range. The composite sensorless motor has the advantages of high efficiency, simple structure, easy control, excellent performance, etc.

[0003] Sensorless permanent magnet synchronous motors are widely used in the field of new energy vehicles. The motors in new energy vehicles often need to run at high power for a long time, resulting in an increase in the temperature of the motor. If the motor is not cooled in time, it will affect the motor performance at best and damage the motor at worst. The prior art with the publication number CN218549648U discloses a water-cooled permanent magnet synchronous motor, which includes a motor body. The motor body is composed of a water-cooled outer shell, a water-cooled machine shell, a stator core, a rotor assembly, a water-cooled rear end cover and a water-cooled front end cover. The water-cooled machine shell is arranged inside the water-cooled outer shell, the stator core is arranged inside the water-cooled machine shell, the water-cooled rear end cover is arranged at one end of the water-cooled outer shell, and the water-cooled front end cover is arranged at the other end of the water-cooled outer shell. The motor is cooled by circulating cooling water.

[0004] However, it is very difficult to improve the effect of water-cooling, and the heat dissipation efficiency is poor, which is not suitable for the working conditions of the motor running at high power for a long time. Content of the Utility Model

[0005] To solve the above problems, the utility model provides a sensorless permanent magnet synchronous motor.

[0006] The technical solution of the utility model is as follows:

[0007] A sensorless permanent magnet synchronous motor includes a housing assembly. The housing assembly has an installation cavity for installing a rotor and a stator inside. The housing assembly includes a machine shell body with openings at both ends. The machine shell body includes an inner shell and an outer shell. The outer shell is sleeved outside the inner shell. The two ends of the outer shell are hermetically connected to the two ends of the inner shell so as to form a cavity between the outer shell and the inner shell. The outer wall of the outer shell is provided with a water inlet pipe and a drain pipe communicating with the cavity. The housing assembly is provided with an oil inlet pipe. An oil injection port communicating with the oil inlet pipe is arranged in the installation cavity. The housing assembly is provided with an oil drain pipe.

[0008] In order to optimize the circuit layout of the permanent magnet synchronous motor and cool the cables connected to the installation cavity part, a junction box is provided on the housing assembly. A number of wiring pipes communicating with the installation cavity are provided in the junction box. The oil inlet pipe is integrated in the junction box, and the oil injection port is adjacent to one end of the wiring pipe located in the installation cavity.

[0009] In order to facilitate real-time control of the heat dissipation efficiency according to the internal temperature of the installation cavity, a temperature sensor and a controller for detecting the internal temperature of the installation cavity are provided on the housing assembly. The temperature sensor controls the water pump and the oil pump through the controller.

[0010] Preferably, a first heat exchanger is provided between the water inlet pipe and the drain pipe, and a water pump is provided on the water inlet pipe or the drain pipe.

[0011] Preferably, a second heat exchanger is provided between the oil inlet pipe and the oil drain pipe, and an oil pump is provided on the oil inlet pipe or the oil drain pipe.

[0012] In order to increase the sealing performance of the housing assembly and prevent the cooling oil from leaking out, the housing assembly further includes a front cover and a rear cover. The front cover and the rear cover are respectively connected to the front end and the rear end of the housing main body, and sealing gaskets are provided between the front cover and the rear cover and the housing main body.

[0013] In order to increase the heat dissipation effect of the cooling water, a number of annular plates are provided at intervals along the length direction of the outer wall of the inner shell. A number of diversion holes are provided circumferentially on each annular plate, and the diversion holes of adjacent annular plates are arranged staggeredly. The diameter of the diversion holes gradually decreases from the water inlet pipe to the drain pipe direction.

[0014] In order to reduce the frictional resistance during the rotation of the rotor, an output shaft is rotatably connected to the front cover, and a bearing seat connecting the rotor is provided in the rear cover.

[0015] In order to increase the heat exchange efficiency with the cooling oil entering the installation cavity, a fixing groove for fixing the bearing seat is provided on the inner side of the rear cover, and a number of heat dissipation plates are arranged at intervals along the circumference of the bearing seat on the inner side of the rear cover. The heat dissipation plates are close to the oil injection port.

[0016] In order to reduce the heat loss inside the outer shell, an adiabatic coating is provided on the outer wall of the outer shell.

[0017] The beneficial effects of the present utility model are as follows:

[0018] 1. The utility model relates to a sensorless permanent magnet synchronous motor. The double-layer protection structure of the inner shell and the outer shell can significantly increase the structural strength of the main body of the motor housing, enhance the protection effect on internal components. Under the action of the water pump, the water in the first heat exchanger enters the cavity through the water inlet pipe and then returns to the first heat exchanger through the drain pipe, where it undergoes heat exchange with the heat exchange components in the first heat exchanger, thereby realizing the water-cooled heat dissipation of the permanent magnet synchronous motor and ensuring the stability of the motor operation. Through the setting of the oil inlet pipe, cooling oil can be sprayed into the installation cavity. The cooling oil directly contacts the components in the installation cavity, absorbs the heat on their surfaces, and then is discharged from the oil drain pipe, further cooling the components in the installation cavity. At the same time, it can also play a lubricating role, reducing the wear and frictional energy loss during the rotation of the motor rotor. The water pump and the oil pump can work independently or cooperatively, significantly optimizing the heat dissipation efficiency of the permanent magnet synchronous motor.

[0019] 2. The setting of the junction box and the wiring pipe facilitates the installation of the circuit. The oil inlet pipe is integrated in the junction box to make the housing assembly more compact. The oil injection port is adjacent to one end of the wiring pipe in the installation cavity. When the permanent magnet synchronous motor operates at high load, the cooling oil ejected from the oil injection port will contact the surface of the cable outside the wiring pipe, reducing the surface temperature of the cable, and thus avoiding the increase in resistance and energy consumption caused by excessive cable temperature.

[0020] 3. The housing assembly is set in a split form, which can greatly improve the efficiency of mass production. Through the setting of the sealing gasket, the sealing performance at the joints between the front cover, the rear cover and the front and rear ends of the main body of the motor housing can be increased, preventing the leakage of cooling oil.

[0021] 4. Through the setting of the spiral plate, the structure of the inner shell can be strengthened. At the same time, the outer edge of the spiral plate can support the outer shell. The spiral channel can guide the cooling water, increasing the contact time between the cooling water and the inner shell, improving the heat absorption effect of the cooling water, and thus improving the heat dissipation efficiency of the cooling water for the permanent magnet synchronous motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] By reading the detailed description of the preferred embodiments below, the solutions and advantages of the present application will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present utility model.

[0023] In the drawings:

[0024] Figure 1 is the structural schematic diagram of the permanent magnet synchronous motor in the present utility model;

[0025] Figure 2 is the schematic diagram of the setting mode of the spiral plate in the present utility model;

[0026] Figure 3Schematic diagram of the internal structure of the housing assembly in the present utility model;

[0027] Figure 4 Front view of the permanent magnet synchronous motor in the present utility model;

[0028] Figure 5 For the present utility model Figure 4 Cross-sectional view taken along line A-A;

[0029] The components represented by the reference numerals in the figure are as follows:

[0030] 1. Main housing; 11. Front cover; 12. Inner housing; 121. Annular plate; 1211. Flow guide hole; 13. Rear cover; 14. Output shaft; 15. Bearing seat; 151. Fixed groove; 152. Heat dissipation plate; 2. Outer shell; 21. Water inlet pipe; 22. Drain pipe; 3. Junction box; 31. Wiring pipe; 4. Oil inlet pipe; 41. Oil injection port; 42. Oil drain pipe. Detailed implementation manners

[0031] The exemplary embodiments of the present disclosure will be described in more detail below in conjunction with the accompanying drawings. It should be noted that these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art. The present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein.

[0032] Embodiment

[0033] Those skilled in the art can understand that in the engineering design of the sensorless low-speed control technology for permanent magnet synchronous motors, the sensorless vector control of permanent magnet synchronous motors includes two parts: starting-low speed control and medium-high speed control. The two control methods complement each other, making up for their respective deficiencies and jointly achieving the full-speed control of permanent magnet synchronous motors. For example, the Chinese invention patent with the application number CN201310515909.6 provides a sensorless vector control system and control method for permanent magnet synchronous motors. The method includes starting-low speed control, medium-high speed control, and transition region control. This prior art can ensure the reliable operation of the sensorless permanent magnet synchronous motor within the full speed range. In the low-speed section, the modeling process has nothing to do with the motor mathematical model and does not require superimposing high-frequency signals. The estimation result will not be affected by the parameter accuracy. The medium-high speed control is still achieved through a sliding mode observer, retaining the characteristics of strong robustness and stable performance of the sliding mode observer. The switching process between the two methods takes into account two factors: speed and rotor position error, ensuring a smooth transition during the switching process. This application is a permanent magnet synchronous motor based on this technology. The permanent magnet synchronous motor proposed in this application often operates for a long time and at high power in the field of new energy vehicles, resulting in more heat generation in the motor and internal components. To solve the heat dissipation problem of the sensorless permanent magnet synchronous motor under long-term and high-power operating conditions, a sensorless-based permanent magnet synchronous motor is proposed, including a housing assembly. The housing assembly has an installation cavity for installing the rotor and stator inside. The housing assembly includes a housing main body 1 with openings at both ends. The housing main body 1 includes an inner housing 12 and an outer housing 2. The outer housing 2 is sleeved outside the inner housing 12. The two ends of the outer housing 2 are hermetically connected to the two ends of the inner housing 12 to form a cavity between the outer housing 2 and the inner housing 12. The double-layer protection structure of the inner housing 12 and the outer housing 2 can significantly increase the structural strength of the housing main body 1 itself and enhance the protection effect on internal components. Further, a water inlet pipe 21 and a drain pipe 22 communicating with the cavity are provided on the outer wall of the outer housing 2. A first heat exchanger is provided between the water inlet pipe 21 and the drain pipe 22. A water pump is provided on the water inlet pipe 21 or the drain pipe 22. Under the action of the water pump, the water in the first heat exchanger enters the cavity through the water inlet pipe 21 and then returns to the first heat exchanger through the drain pipe 22, exchanging heat with the heat exchange component in the first heat exchanger, thereby realizing the water-cooled heat dissipation of the permanent magnet synchronous motor and ensuring the stability of the motor operation. In addition, an oil inlet pipe 4 is provided on the housing assembly, and an oil injection port 41 communicating with the oil inlet pipe 4 is provided in the installation cavity. A drain pipe 42 is provided on the housing assembly. Through the setting of the oil inlet pipe 4, cooling oil can be sprayed into the installation cavity. The cooling oil directly contacts the components in the installation cavity, absorbs the heat on their surfaces, and then is discharged from the drain pipe 42, further cooling the components in the installation cavity. At the same time, it can also play a lubricating role, reducing the wear and frictional energy loss during the rotation of the motor rotor.Specifically, a second heat exchanger is provided between the inlet pipe 4 and the drain pipe 42, and an oil pump is provided on the inlet pipe 4 or the drain pipe 42. Under the action of the oil pump, the cooling oil in the second heat exchanger is pumped into the installation cavity through the inlet pipe 4 and sprayed onto the surface of the components in the installation cavity through the oil injection port 41. After absorbing the heat of the components, it flows back to the second heat exchanger through the drain pipe 42 and exchanges heat with the heat exchange components in the second heat exchanger, realizing oil cooling and heat dissipation of the permanent magnet synchronous motor, and further ensuring the stability of the motor operation.

[0034] A plurality of annular plates 121 are provided at intervals along the length direction of the outer wall of the inner shell 12. A plurality of diversion holes 1211 are provided circumferentially on each annular plate 121. The diversion holes 1211 of adjacent annular plates 121 are arranged staggeredly. The diameter of the diversion holes 1211 gradually decreases from the water inlet pipe 21 to the water drain pipe 22. The arrangement of the annular plates 121 can strengthen the structural strength of the inner shell 12 while also supporting the outer shell 2. Cooling water flow channels are formed between adjacent annular plates 12. The staggered diversion holes 1211 can connect the flow channels and also disturb the cooling water entering the cooling water flow channels, enabling the cooling water to quickly enter adjacent channels, and then realizing that the cooling water quickly covers the surface of the inner shell 12 and exchanges heat with the inner shell 12, improving the heat dissipation efficiency.

[0035] As a preferred embodiment of the present application, it further includes a control component for the switches of the water pump and the oil pump. The control component can control the water pump and the oil pump to be turned on separately or simultaneously. When the external temperature of the permanent magnet synchronous motor is between -40°C and 0°C, at this time, due to the cold water freezing at low temperature and poor fluidity, the control component controls the oil pump to be turned on alone, and the permanent magnet synchronous motor is cooled by oil cooling. When the external temperature of the permanent magnet synchronous motor is above 0°C, the control component controls the water pump to work alone or the water pump and the oil pump to work simultaneously to realize the cooling of the permanent magnet synchronous motor, solving the heat dissipation problem of the permanent magnet synchronous motor under different temperature conditions. When the motor is operating at low power, the control component controls the water pump to be turned on, and the motor is cooled by water cooling. When the motor is operating at high power, the control component controls the oil pump to be turned on, and the motor is efficiently cooled by oil cooling.

[0036] A temperature sensor for detecting the internal temperature of the installation cavity and a controller are provided on the housing assembly. The temperature sensor controls the water pump and the oil pump through the controller. The temperature sensor detects the internal temperature of the installation cavity and transmits the temperature signal to the controller. The controller controls the rotation speeds of the water pump and the oil pump, thereby realizing real-time control of the heat dissipation efficiency according to the change of the internal temperature of the installation cavity.

[0037] In addition, the heat absorbed by the heat exchange components in the first heat exchanger and the second heat exchanger can be reused by the staff in this field. For example, in the field of new energy vehicles, this part of the heat is used for auxiliary heating in the cab, etc.

[0038] It should be noted that the first heat exchanger, the second heat exchanger, the heat exchange assembly and their installation methods in this application are all mature existing technologies. Specifically, a tubular heat exchanger or a wound-tube heat exchanger can be used. The cooling oil is a special oil variety that is non-conductive and non-magnetic. The control component can use a numerical control computer device, and no further elaboration will be made here.

[0039] Furthermore, an adiabatic wrapping layer is provided on the outer wall of the outer shell 2. The adiabatic wrapping layer is preferably made of heat-insulating cotton. By providing the adiabatic wrapping layer, the heat dissipation of the outer shell 2 can be reduced, so that the heat inside the outer shell 2 is fully absorbed by the cooling water and the cooling oil and then transferred to the first heat exchanger, the second heat exchanger and the heat exchange assembly, improving the heat recovery rate. On the other hand, the setting of the adiabatic wrapping layer can also play a role in buffering and protecting the outer shell 2.

[0040] Refer to Figure 1 、 Figure 2 、 Figure 4 and Figure 5 , a junction box 3 is provided on the housing assembly. A plurality of wiring pipes 31 communicating with the installation cavity are provided in the junction box 3. The setting of the junction box 3 and the wiring pipes 31 facilitates the installation of the circuit. The oil inlet pipe 4 is integrated in the junction box 3 to make the housing assembly more compact. The oil injection port 41 is adjacent to one end of the wiring pipe 31 located in the installation cavity. During the high-load operation of the permanent magnet synchronous motor, the cooling oil ejected from the oil injection port 41 will contact the surface of the cable outside the wiring pipe 31, reducing the surface temperature of the cable, and thus avoiding the increase in resistance and energy consumption caused by too high cable temperature.

[0041] Refer to Figures 1 - 5 , the housing assembly further includes a front cover 11 and a rear cover 13. The front cover 11 and the rear cover 13 are respectively connected to the front end and the rear end of the housing main body 1. Sealing gaskets are provided between the front cover 11 and the rear cover 13 and the housing main body 1. The housing assembly is provided in a split type, which can greatly improve the efficiency of mass production. By providing the sealing gaskets, the sealing performance at the joints between the front cover 11, the rear cover 13 and the front and rear ends of the housing main body 1 can be increased, preventing the leakage of the cooling oil.

[0042] A spiral plate 121 is provided on the outer wall of the inner shell 12 to form a spiral channel in the cavity that communicates from the water inlet pipe 21 to the drain pipe 22. By providing the spiral plate 121, the structure of the inner shell 12 can be strengthened. At the same time, the outer edge of the spiral plate 121 can support the outer shell 2. The spiral channel can guide the cooling water, increasing the contact time between the cooling water and the inner shell 12, improving the heat absorption effect of the cooling water, and thus improving the heat dissipation efficiency of the cooling water for the permanent magnet synchronous motor.

[0043] In addition, refer to Figure 3 and Figure 5, those skilled in the art can understand that the output shaft 14 is rotatably connected to the front cover 11, the output shaft 14 is fixedly connected to the rotor in the installation cavity, a bearing seat 15 for connecting the rotor is provided in the rear cover 13, and one end of the rotor away from the output shaft 14 is connected to the bearing seat 15 to reduce the frictional force during the rotation of the rotor and reduce the energy loss caused by friction.

[0044] Furthermore, a fixing groove 151 for fixing the bearing seat 15 is provided on the inner side of the rear cover 13, and a plurality of heat dissipation plates 152 are arranged at intervals along the circumferential direction of the bearing seat 15 on the inner side of the rear cover 13, and the heat dissipation plates 152 are close to the oil injection port 41. Through the arrangement of the heat dissipation plates 152, the heat generated by the components in the installation cavity can be absorbed, and efficient heat exchange can be carried out with the cooling oil entering the installation cavity, increasing the heat exchange efficiency and heat exchange effect.

Claims

1. A sensorless permanent magnet synchronous motor, comprising a housing assembly, wherein an installation cavity for installing a rotor and a stator is provided inside the housing assembly, characterized in that, An oil cooling mechanism for cooling the installation cavity is provided on the housing assembly. The housing assembly includes a housing body (1) with openings at both ends. The housing body (1) includes an inner shell (12) and an outer shell (2). The two ends of the outer shell (2) are hermetically connected to the two ends of the inner shell (12) to form a cavity between the outer shell (2) and the inner shell (12). A water inlet pipe (21) and a drain pipe (22) communicating with the cavity are provided on the outer wall of the outer shell (2).

2. A sensorless permanent magnet synchronous motor according to claim 1, wherein A junction box (3) is provided on the housing assembly. A number of wiring pipes (31) communicating with the installation cavity are provided in the junction box (3). The oil inlet pipe (4) is integrated in the junction box (3), and the oil injection port (41) is adjacent to one end of the wiring pipe (31) located in the installation cavity.

3. The sensorless permanent magnet synchronous motor according to claim 2, characterized in that, A first heat exchanger is provided between the water inlet pipe (21) and the drain pipe (22), and a water pump is provided on the water inlet pipe (21) or the drain pipe (22).

4. A sensorless permanent magnet synchronous motor according to claim 3, wherein, The oil cooling mechanism includes an oil inlet pipe (4). An oil injection port (41) communicating with the oil inlet pipe (4) is provided in the installation cavity. A drain pipe (42) is provided on the housing assembly. A second heat exchanger is provided between the oil inlet pipe (4) and the drain pipe (42), and an oil pump is provided on the oil inlet pipe (4) or the drain pipe (42).

5. A sensorless permanent magnet synchronous motor according to claim 4, characterized in that, A temperature sensor for detecting the internal temperature of the installation cavity and a controller are provided on the housing assembly. The temperature sensor controls the water pump and the oil pump through the controller.

6. A sensorless permanent magnet synchronous motor according to claim 1, characterized in that, The housing assembly further includes a front cover (11) and a rear cover (13). The front cover (11) and the rear cover (13) are respectively connected to the front end and the rear end of the housing body (1). Sealing gaskets are provided between the front cover (11) and the rear cover (13) and the housing body (1).

7. A sensorless permanent magnet synchronous motor according to claim 1, characterized in that, A number of annular plates (121) are provided on the outer wall of the inner shell (12) at intervals along the length direction. A number of flow guiding holes (1211) are provided circumferentially on each annular plate (121). The flow guiding holes (1211) of adjacent annular plates (121) are arranged staggeredly. The diameter of the flow guiding holes (1211) gradually decreases from the direction of the water inlet pipe (21) to the direction of the drain pipe (22).

8. A sensorless permanent magnet synchronous motor according to claim 6, characterized in that, An output shaft (14) is rotatably connected to the front cover (11), and a bearing seat (15) connecting the rotor is provided in the rear cover (13).

9. A sensorless permanent magnet synchronous motor according to claim 8, wherein, A fixing groove (151) for fixing the bearing seat (15) is provided on the inner side of the rear cover (13). A number of heat dissipation plates (152) are provided at intervals along the circumference of the bearing seat (15) on the inner side of the rear cover (13). The heat dissipation plates (152) are close to the oil injection port (41).

10. A sensorless permanent magnet synchronous motor according to claim 1, characterized in that, An adiabatic coating is provided on the outer wall of the outer shell (2).

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