Permanent magnet synchronous motor for air compressor
By optimizing the stator and rotor structure of the permanent magnet synchronous motor for air compressors, and adopting a large inductance stator core and embedded permanent magnets, the problems of current fluctuation and vibration noise were solved, achieving stable motor operation and cost reduction.
Patent Information
- Application Number
- CN202423086487.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-13
- Publication Date
- 2025-11-14
- Estimated Expiration
- 2034-12-13
AI Technical Summary
Traditional air compressors' permanent magnet brushless motors experience large current fluctuations under FOC sinusoidal current control, leading to issues with motor stability, vibration, and noise. Furthermore, mechanical position sensors increase cost and complexity.
A permanent magnet synchronous motor for air compressors was designed, which adopts a large inductance stator core and an embedded permanent magnet structure. It is suitable for FOC sinusoidal current control and eliminates the mechanical position sensor. The inductance and saliency ratio of the motor are improved by optimizing the stator and rotor structure.
This achieves smooth motor operation, reduces current fluctuations and vibration noise, lowers costs, and improves reliability and output capacity.
Smart Images
Figure CN223553108U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of motor technology, specifically a permanent magnet synchronous motor for an air compressor. Background Technology
[0002] An air compressor is a device used to compress gas. In modern industry, air compressors are key equipment and are widely used in various power systems and processes. Currently, permanent magnet brushless motors are increasingly used in the air compressor field because they have advantages such as small size, high power, wide speed range, energy saving and environmental protection.
[0003] Traditional high-pressure permanent magnet brushless air compressors typically use large electrolytic capacitors after the rectifier bridge to filter AC power into DC power before driving the motor. While large electrolytic capacitors improve the stability of the rectified voltage, the instantaneous charging current introduces glitches, resulting in a low power factor and making it difficult for the machine to pass EMC tests. To improve the system power factor, passive PFC circuits or small electrolytic capacitors are used in the rectifier bridge. However, the rectified voltage is fluctuating, which can cause excessive current fluctuations when the motor is controlled by FOC (Fault-Oriented Control).
[0004] Furthermore, the traditional BLDC square wave current control method results in large motor current harmonics, poor motor operation stability, and high vibration and noise. However, after changing the motor to FOC sinusoidal wave current control, the motor's stability and vibration and noise are significantly improved. Therefore, it is necessary to design an air compressor that is suitable for FOC sinusoidal wave current control. Utility Model Content
[0005] To address the problems in related technologies, this invention provides a permanent magnet synchronous motor for air compressors. This motor has a large inductance, is suitable for FOC sinusoidal current control, and can suppress current fluctuations in the motor. This device solves the problem of poor motor stability in air compressors.
[0006] To solve the above problems, the following technical solutions are provided:
[0007] This utility model discloses a permanent magnet synchronous motor for an air compressor, comprising a stator assembly and a rotor assembly, wherein the rotor assembly is disposed inside the stator assembly; the stator assembly contains a stator core, and twelve stator slots are evenly distributed along the circumferential direction on the inner circumferential surface of the stator core; the rotor assembly contains a rotor core, and ten sets of permanent magnets are evenly distributed along the circumferential direction of the rotor core; the outer diameter of the stator core is 70-130 mm, and the ratio of the inner diameter of the stator core to the outer diameter of the stator core ranges from 0.47 to 0.55.
[0008] In the above scheme, the ratio of the inner diameter to the outer diameter of the stator core is in the range of 0.47 to 0.55, which is beneficial to reduce the diameter of the rotor core. This allows the motor to increase the number of winding turns while maintaining the same back EMF coefficient and torque coefficient, thereby increasing the motor inductance. This motor has a large inductance and is suitable for FOC sinusoidal current control, thus solving the problem of poor motor stability in air compressors. Increasing the number of coil turns and winding diameter of the motor stator winding and reducing the size of the rotor core can increase the motor inductance and suppress current fluctuations.
[0009] The permanent magnet is embedded in the rotor core, and the permanent magnet is evenly arranged along the circumference of the rotor core.
[0010] In the above scheme, by setting permanent magnets, which are embedded in the rotor core, a large saliency ratio can be obtained, making the motor suitable for high-frequency injection sensorless control.
[0011] The stator assembly and rotor assembly are connected together to form a motor. The motor is a sensorless motor, and the salient pole ratio of the motor is greater than or equal to 1.2.
[0012] With the above scheme, the saliency ratio of the motor is greater than or equal to 1.2, which makes the motor suitable for high-frequency injection sensorless control scheme, eliminating the need for mechanical position sensors, reducing motor cost and improving reliability.
[0013] Each group of permanent magnets includes two magnets arranged in a V-shape.
[0014] The included angle between the two magnets is greater than 60°.
[0015] The above scheme incorporates V-shaped permanent magnets, and the V-shaped arrangement enables the magnetic field to have a focusing effect, thereby improving the motor's output capability.
[0016] The stator assembly includes a stator winding wound around the stator core; the rotor assembly includes a rotor shaft around which the rotor core is sleeved.
[0017] The above solution results in a simple motor structure.
[0018] The above solution has the following advantages:
[0019] 1. The permanent magnet synchronous motor for air compressors of this utility model includes a stator assembly and a rotor assembly. The inner circumferential surface of the stator core has twelve evenly distributed stator slots spaced circumferentially, and ten sets of permanent magnets are evenly distributed circumferentially along the rotor core. The outer diameter of the stator core is 70–130 mm, and the ratio of the inner diameter to the outer diameter of the stator core ranges from 0.47 to 0.55. This is beneficial for reducing the diameter of the rotor core, allowing the motor to increase the number of winding turns while maintaining the same back EMF coefficient and torque coefficient, thereby increasing the motor inductance. This motor has a large inductance, making it suitable for FOC sinusoidal current control. It is beneficial for improving the stability of the motor in the air compressor. Increasing the number of coil turns and the winding diameter of the stator winding, while reducing the size of the rotor core, increases the motor inductance and suppresses current fluctuations.
[0020] 2. The permanent magnets are embedded in the rotor core and evenly arranged around the circumference of the rotor core, which can achieve a large saliency ratio, making the motor suitable for high-frequency injection sensorless control. The saliency ratio of the motor is greater than or equal to 1.2, which makes the motor suitable for high-frequency injection sensorless control schemes, eliminating the need for mechanical position sensors, reducing motor costs, and improving reliability. Each group of permanent magnets includes two magnets, and the permanent magnets are arranged in a V-shape. The V-shape arrangement can give the magnetic field a magnetic focusing effect, thereby improving the output capability of the motor. Attached Figure Description
[0021] To make the content of this utility model easier to understand, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein:
[0022] Figure 1 This is a schematic diagram of a permanent magnet synchronous motor for an air compressor.
[0023] Figure 2 This is a schematic diagram of the stator core in a permanent magnet synchronous motor for an air compressor.
[0024] Figure 3 This is a schematic diagram of the rotor core in a permanent magnet synchronous motor for an air compressor.
[0025] Figure 4 This is a schematic diagram of the structure of motor E in Comparative Example 1-2;
[0026] Figure 5 This is a comparison chart of the efficiency of motor B and motor E in Example 1;
[0027] Figure 6 This is a comparison chart of the wear and tear of motor B and motor E in Example 1;
[0028] Figure 7This is a comparison diagram of the phase currents of motor B and motor E in Example 1;
[0029] Explanation of reference numerals in the attached diagram: 1. Stator core; 2. Stator slot; 3. Rotor core; 4. Permanent magnet; 401. Magnet. Detailed Implementation
[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0031] In specific embodiment 1, such as Figure 1 As shown, the permanent magnet synchronous motor for an air compressor of this utility model includes a stator assembly and a rotor assembly, with the rotor assembly disposed inside the stator assembly; the stator assembly contains a stator core 1 and stator windings, the stator windings being wound around the stator core 1, as shown... Figure 2 As shown, twelve stator slots 2 are evenly distributed along the circumferential direction on the inner circumferential surface of the stator core 1. The outer diameter of the stator core 1 is 70-130 mm, and the ratio of the inner diameter D2 to the outer diameter D1 of the stator core 1 ranges from 0.47 to 0.55. This increases the number of turns and the winding diameter of the motor stator winding, which is beneficial for reducing the diameter of the rotor core 3. This allows the motor to increase the number of winding turns while maintaining the same back EMF coefficient and torque coefficient, thereby increasing the motor inductance, suppressing current fluctuations, and enabling the motor to operate smoothly. Figure 3 As shown, the rotor assembly includes a rotor core 3 and a rotor shaft. Ten sets of permanent magnets 4 are evenly arranged along the circumference of the rotor core 3, and the rotor core 3 is sleeved on the rotor shaft.
[0032] The motor adopts a ten-pole twelve-slot motor. In Example 1-1, the ratio of the inner diameter to the outer diameter of the stator core 1 is 0.47. The motor is motor A. Motor A has a working efficiency of 81.2%, a winding copper loss of 282W, a stator core 1 loss of 16W, and a maximum phase current of 16A.
[0033] In Examples 1-2, the ratio of the inner diameter to the outer diameter of the stator core 1 is 0.53. The motor is motor B, which has an efficiency of 82%, a winding copper loss of 265W, a stator core 1 loss of 20W, and a maximum phase current amplitude of 15A.
[0034] In Examples 1-3, the ratio of the inner diameter to the outer diameter of the stator core 1 is 0.55. The motor is motor C, which has an efficiency of 81%, a winding copper loss of 279W, a stator core 1 loss of 22W, and a maximum phase current amplitude of 17A.
[0035] In Comparative Example 1-1, the ratio of the inner diameter to the outer diameter of the stator core 1 is 0.41. The motor is motor D, which has an efficiency of 77%, a winding copper loss of 350W, a stator core 1 loss of 13W, and a maximum phase current of 19A.
[0036] In Comparative Examples 1-2, the ratio of the inner diameter to the outer diameter of the stator core 1 is 0.6. This motor is motor E. Figure 4 As shown, motor E has an efficiency of 78%, a winding copper loss of 320W, a stator core 1 loss of 25W, and a maximum phase current of 20A.
[0037] like Figures 5-7 As shown, by comparing Examples 1-1 to 1-3 with Comparative Examples 1-1 to 1-2, it can be seen that the working efficiency of motors A, B, and C is higher than that of motors D and E. The winding copper loss of motors A, B, and C is lower than that of motors D and E. Furthermore, the maximum phase current amplitude of motors A, B, and C is smaller than that of motors D and E. Therefore, when the ratio of the inner diameter to the outer diameter of the stator core 1 is 0.47 to 0.55, the current stress of the motor is low, the cost is low, and the heat generation is less.
[0038] In specific embodiment 2, the difference between this embodiment and embodiment 1 is that the permanent magnet 4 is embedded in the rotor core 3, and the permanent magnet 4 is evenly arranged along the circumference of the rotor core 3, which can obtain a larger saliency ratio, so that the motor is suitable for high-frequency injection sensorless control.
[0039] In specific embodiment 3, the difference between this embodiment and embodiments 1 and 2 is that the stator assembly and rotor assembly in this embodiment are connected together to form a motor. The motor is a sensorless motor with a saliency ratio greater than or equal to 1.2, which can eliminate the need for a mechanical position sensor, reduce motor cost and improve motor reliability. The saliency ratio is the ratio of the q-axis inductance to the d-axis inductance of the motor, i.e., saliency ratio = Lq / Ld.
[0040] In a specific embodiment 4, such as Figure 3 As shown, the difference between this embodiment and embodiments 1 to 3 is that each group of permanent magnets 4 in this embodiment includes two magnets 401. The permanent magnets 4 are arranged in a V-shape. The V-shape arrangement can improve the magnetic field concentration ability of the rotor, which is beneficial to increasing the output capacity of the motor. The included angle between the two magnets 401 is greater than 60°.
[0041] In the description of this utility model, it should be understood that the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. In the description of this utility model, unless otherwise specified and limited, it should be noted that the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components, and can be direct connections or indirect connections through an intermediate medium. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.
[0042] Obviously, the above embodiments are merely examples for clear illustration and are not intended to limit the implementation. For those skilled in the art, other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all implementation methods here, and any obvious variations or modifications derived therefrom are still within the protection scope of this utility model.
Claims
1. A permanent magnet synchronous motor for an air compressor, characterized in that, The system includes a stator assembly and a rotor assembly, wherein the rotor assembly is disposed inside the stator assembly; the stator assembly contains a stator core (1), and twelve stator slots (2) are evenly distributed along the circumferential direction on the inner circumferential surface of the stator core (1); the rotor assembly contains a rotor core (3), and ten sets of permanent magnets (4) are evenly distributed along the circumferential direction of the rotor core (3); the outer diameter of the stator core (1) is 70~130mm, and the ratio of the inner diameter of the stator core (1) to the outer diameter of the stator core (1) is in the range of 0.47~0.
55.
2. The permanent magnet synchronous motor for an air compressor as described in claim 1, characterized in that, The permanent magnet (4) is embedded in the rotor core (3), and the permanent magnet (4) is evenly arranged along the circumference of the rotor core (3).
3. A permanent magnet synchronous motor for an air compressor as described in claim 1, characterized in that, The stator assembly and rotor assembly are connected together to form a motor. The motor is a sensorless motor and the salient pole ratio of the motor is greater than or equal to 1.
2.
4. A permanent magnet synchronous motor for an air compressor as described in claim 1, characterized in that, Each set of permanent magnets (4) includes two magnets (401), and the permanent magnets (4) are arranged in a V-shape.
5. A permanent magnet synchronous motor for an air compressor as described in claim 4, characterized in that, The included angle between the two magnets (401) is greater than 60°.
6. A permanent magnet synchronous motor for an air compressor as described in claim 1, characterized in that, The stator assembly includes a stator winding wound around the stator core (1); the rotor assembly includes a rotor shaft with the rotor core (3) sleeved on the rotor shaft.