Electric compressor position recognition device and recognition method

Abstract

The invention discloses an electric compressor position recognition device and recognition method, and belongs to the technical field of compressor controllers, and the device comprises a shell assembly which comprises a first shell and a second shell which are connected with each other; the rotating assembly comprises an electric compressor rotor and a shaft, the electric compressor rotor is arranged in the first shell, and the shaft penetrates through the electric compressor rotor and is connected with the electric compressor rotor for common rotation; the position recognition assembly comprises a magnet embedded in the shaft, a PCBA installed on the second shell and an angle sensor installed on the PCBA, and the angle sensor achieves position recognition by detecting the magnetic field change of the magnet rotating along with the shaft; the controller is used for adjusting the torque and the speed of the rotor of the electric compressor according to the recognized position information, the requirement of the vehicle-mounted refrigerator can be met by accurately controlling the low rotating speed of the compressor, and therefore the number of compressors for independent refrigeration of the refrigerator of the whole vehicle is reduced, and the cost of the whole vehicle is reduced.

Description

Technical Field

[0001] The invention relates to a position identification device and an identification method for an electric compressor, belonging to the technical field of compressor controllers. Background Art

[0002] With the development of technology, many cars are equipped with onboard refrigerators. The existing electric compressors have no angle sensors, and the motor speed is estimated by software algorithms, which cannot achieve precise control at low speeds. In car refrigerators, due to the low power of car refrigerators, precise control is required at low speeds. Therefore, the refrigeration of car refrigerators cannot be carried out by traditional electric air-conditioning compressors. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide an electric compressor position identification device and identification method, which can accurately control the low speed of the compressor to meet the needs of a vehicle refrigerator, thereby reducing the number of compressors for refrigerator refrigeration in the entire vehicle, thereby reducing the cost of the entire vehicle.

[0004] To achieve the above object, the present invention is implemented by adopting the following technical solutions: In a first aspect, the present invention provides a position identification device for an electric compressor, comprising: A housing assembly comprising a first housing and a second housing connected to each other; A rotating assembly, comprising an electric compressor rotor and a shaft, wherein the electric compressor rotor is disposed in the first housing, and the shaft passes through the electric compressor rotor and is connected thereto for common rotation; A position identification component, comprising a magnet embedded in the shaft, a PCBA mounted on the second housing, and an angle sensor mounted on the PCBA, wherein the angle sensor realizes position identification by detecting a change in a magnetic field of the magnet as the shaft rotates; A controller is used to adjust the torque and speed of the electric compressor rotor based on the identified position information.

[0005] Furthermore, the angle sensor is mounted on the PCBA through a patch process and is used to detect the change of the magnetic field when the shaft rotates. The angle sensor includes a plurality of GMR elements, and the plurality of GMR elements are connected to form a Wheatstone bridge structure.

[0006] Furthermore, the PCBA is fastened to the second housing by bolts.

[0007] Furthermore, the second shell is made of metal or plastic.

[0008] Furthermore, a sealing device capable of maintaining sealing under a pressure of 20KPA is provided between the first shell and the second shell.

[0009] Furthermore, the shaft has a groove, and the magnet is embedded in the groove of the shaft.

[0010] In a second aspect, the present invention provides an identification method of the electric compressor position identification device according to any one of the above items, comprising: Get the actual angle value detected by the angle sensor; According to the actual angle value, the original value of the angle sensor is calculated; Calculating the angle position of the electric compressor rotor according to the original value of the angle sensor; The stator current is regulated by the angular position of the electric compressor rotor, thereby controlling the torque and adjusting the speed.

[0011] Furthermore, the original value of the angle sensor is calculated based on the actual angle value, and the formula is as follows: ; in, is the original value of the angle sensor, N The number of bits of the actual angle value. b Indicates the actual angle value; Indicates the number of digits in the summation formula, Indicates the highest bit. Indicates the value of the highest bit of the actual angle value. Indicates the actual angle value to be summed.

[0012] Furthermore, the angle position of the electric compressor rotor is calculated based on the original value of the angle sensor, and the formula is as follows: ; in, Indicates the angular position of the electric compressor rotor.

[0013] Furthermore, the stator current is adjusted by the angular position of the electric compressor rotor to control the torque and adjust the speed, including: Calculate the electrical angle of the electric compressor rotor based on the angular position of the electric compressor rotor , where the electrical angle of the electric compressor rotor is equal to the electric compressor rotor angular position multiplied by the number of pole pairs of the motor; Using Clarke transformation, the obtained stator current ( , , ), transformed to the stator stationary coordinate system (α-β), the formula is as follows: ; The electrical angle of the electric compressor rotor Perform Park transformation to transform the current component ( , ) is transformed into the rotating coordinate system (dq), the formula is as follows: ; Among them, in the dq coordinate system, represents the magnetic flux component, represents the torque component; Use PI controller to regulate and Error, generate the corresponding d-axis and q-axis voltage instructions and ; The voltage command and To transform from the dq rotating coordinate system back to the stationary α-β coordinate system, use the inverse Park transform, the formula is as follows: ; in, and is the transformed voltage instruction; The converted voltage command and , the required three-phase voltage waveform is generated on the stator, thereby controlling the torque and adjusting the speed.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides an electric compressor position identification device and identification method, which realizes position identification by detecting the magnetic field change of a magnet as the shaft rotates through an angle sensor; and according to the identified position information, adjusts the torque and speed of the electric compressor rotor, and can accurately control the low speed of the compressor to meet the needs of a vehicle refrigerator, thereby reducing the compressor for independent refrigeration of the refrigerator in the whole vehicle, thereby reducing the cost of the whole vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of a method for identifying the position of an electric compressor according to the present invention; Figure 2 A schematic diagram of the principle of controlling the motor speed provided by an embodiment of the present invention.

[0016] In the figure: 1. first housing; 2. electric compressor rotor; 3. shaft; 3.1. magnet; 4. second housing; 5. PCBA; 5.1. angle sensor. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0018] Embodiment 1, as Figure 1 As shown, this embodiment introduces an electric compressor position identification device, including a first housing 1, an electric compressor rotor 2, a shaft 3, a magnet 3.1, a second housing 4, a PCBA5, and an angle sensor 5.1. The shaft 3 is equipped with a magnet 3.1 and passes through the electric compressor rotor 2 and rotates with the electric compressor rotor 2. The angle sensor 5.1 is a chip, which is mounted on the PCBA5 using a patch process, and the PCBA5 is bolted to the second housing 4. There is a groove on the shaft 3, and the magnet 3.1 is embedded in the groove on the shaft 3. There is a sealing device between the first housing 1 and the second housing 4, and the first housing 1 and the second housing 4 are completely sealed even under a pressure of 20KPa. Any low magnetic permeability material such as the second housing 4 is within the protection scope of the present invention. The angle sensor 5.1 adopts a vertically integrated design, which means that the areas sensitive to GMR (giant magnetoresistance effect) are concentrated on the logic part of the device, and the resistance of these areas will change with the change of the direction of the applied magnetic field.

[0019] The angle sensor 5.1 internally contains four GMR elements connected in a Wheatstone bridge configuration. These elements are able to detect one of the two components of an applied magnetic field: X component, generates Vx signal (cosine wave); Y component, generates Vy signal (sine wave); This full-bridge configuration allows for the maximum GMR signal to be obtained while also effectively offsetting the effect of temperature changes on resistance. The radially magnetized magnet 3.1 used in the angle sensor 5.1 rotates above the GMR element, so that the output signals of the two bridges have a 90° phase difference, forming a sinusoidal waveform. Next, the output signals of the two bridges are sampled by an ADC (analog-to-digital converter) to convert the analog signals into digital signals. According to the following formula: ; To obtain the original value of the angle sensor, the original X and Y signals are processed by the trigonometric function ARCTAN2, and the original value of the angle sensor is substituted into the following formula: ; Convert the actual position angle value. Then the real 360° rotation angle of the sensor can be calculated. This method uses the phase difference between the X and Y signals to accurately calculate the azimuth of the magnet, and then accurately identify the angular position of the electric compressor rotor; in, is the original value of the angle sensor,N The number of bits of the actual angle value. b Indicates the actual angle value; Indicates the number of digits in the summation formula, Indicates the highest bit. Indicates the value of the highest bit of the actual angle value. Indicates the sum of the actual angle values. Indicates the angular position of the electric compressor rotor.

[0020] In summary, the electric compressor position identification device and method provided by the present invention has the advantage of accurately controlling the motor speed. Then based on the FOC principle, the second housing can adjust the current to control the torque and then adjust the speed. The principle block diagram is as follows Figure 2 As shown; The specific principles are as follows: 1. Angle position signal acquisition and coordinate transformation The built-in PMSM usually obtains the azimuth angle of the magnet through an angle sensor to accurately identify the angle position signal of the electric compressor rotor. This angle is called the mechanical angle. In order to accurately control the torque and flux, we need the electrical angle of the electric compressor rotor. (Mechanical angle multiplied by the number of pole pairs of the motor). This electrical angle is used to convert the three-phase stator current ( , , ) is transformed to the stator stationary coordinate system (α-β).

[0021] 1.1 Clarke transformation First, use Clarke transformation to transform the three-phase current ( , , ) is transformed to the stator stationary coordinate system (α-β): ; This transformation converts three-phase quantities into two-phase quantities, simplifying subsequent mathematical processing.

[0022] 1.2 Park Transform Next, the electrical angle of the electric compressor rotor Perform Park transformation to transform the current component ( , ) is transformed into the rotating coordinate system (dq): ; In the dq coordinate system, represents the magnetic flux component, Represents the torque component, so that the torque and flux can be controlled independently to achieve the purpose of decoupling.

[0023] 2. Current control (PI controller) In FOC, the d-axis current and q-axis current Will be controlled separately. Usually a PI controller is used to adjust and Error, generate the corresponding d-axis and q-axis voltage instructions and .

[0024] 3. Inverse Park transform (dq to α-β) Generated voltage command and It is necessary to transform from the dq rotating coordinate system back to the stationary α-β coordinate system. Use the inverse Park transform: .

[0025] 4. Space Vector Pulse Width Modulation (SVPWM) Voltage command generated in α-β coordinate system and The input is sent to the space vector pulse width modulation (SVPWM) module. SVPWM generates the required three-phase voltage waveform on the stator by controlling the switching state of the inverter.

[0026] 5. Inverter circuit Under the switching action of the inverter, the output three-phase AC power is sent to the motor stator. Since SVPWM makes the direction and amplitude of the magnetic field generated on the motor stator close to the expected value, the motor can achieve the required torque and speed according to the set current vector.

[0027] 6. Motor torque and speed regulation Through the above process, the second housing can adjust the current to control the torque and then adjust the speed. In the speed control system, the outer loop is the speed loop and the inner loop is the current loop. This double closed-loop structure ensures the system's rapid response and precise torque control.

[0028] Embodiment 2: This embodiment provides an identification method of the electric compressor position identification device according to any one of Embodiment 1, comprising: Get the actual angle value detected by the angle sensor; According to the actual angle value, the original value of the angle sensor is calculated; Calculating the angle position of the electric compressor rotor according to the original value of the angle sensor; The stator current is regulated by the angular position of the electric compressor rotor, thereby controlling the torque and adjusting the speed.

[0029] The angle sensor original value is calculated based on the actual angle value, and the formula is as follows: ; in, is the original value of the angle sensor, N The number of bits of the actual angle value. b Indicates the actual angle value; Indicates the number of digits in the summation formula, Indicates the highest bit. Indicates the value of the highest bit of the actual angle value. Indicates the actual angle value to be summed.

[0030] The angle position of the electric compressor rotor is calculated based on the original value of the angle sensor, and the formula is as follows: ; in, Indicates the angular position of the electric compressor rotor.

[0031] The method of regulating the stator current by adjusting the angular position of the electric compressor rotor, thereby controlling the torque and adjusting the speed, includes: Calculate the electrical angle of the electric compressor rotor based on the angular position of the electric compressor rotor , where the electrical angle of the electric compressor rotor is equal to the electric compressor rotor angular position multiplied by the number of pole pairs of the motor; Using Clarke transformation, the obtained stator current ( , , ), transformed to the stator stationary coordinate system (α-β), the formula is as follows: ; The electrical angle of the electric compressor rotor Perform Park transformation to transform the current component ( , ) is transformed into the rotating coordinate system (dq), the formula is as follows: ; Among them, in the dq coordinate system, represents the magnetic flux component, represents the torque component; Use PI controller to regulate and Error, generate the corresponding d-axis and q-axis voltage instructions and ; The voltage command and To transform from the dq rotating coordinate system back to the stationary α-β coordinate system, use the inverse Park transform, the formula is as follows: ; in, and is the transformed voltage instruction; The converted voltage command and , the required three-phase voltage waveform is generated on the stator, thereby controlling the torque and adjusting the speed.

[0032] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A position identification device for an electric compressor, characterized in that: include: A housing assembly comprising a first housing (1) and a second housing (4) connected to each other; A rotating assembly, comprising an electric compressor rotor (2) and a shaft (3), wherein the electric compressor rotor (2) is arranged in a first housing (1), and the shaft (3) passes through the electric compressor rotor (2) and is connected thereto so as to rotate together; A position identification component, comprising a magnet (3.1) embedded in a shaft (3), a PCBA (5) mounted on a second housing (4), and an angle sensor (5.1) mounted on the PCBA (5), wherein the angle sensor (5.1) realizes position identification by detecting changes in the magnetic field of the magnet (3.1) as the shaft (3) rotates; A controller is used to adjust the torque and speed of the electric compressor rotor (2) according to the identified position information.

2. The electric compressor position identification device according to claim 1, characterized in that: The angle sensor (5.1) is mounted on the PCBA (5) through a patch process and is used to detect changes in the magnetic field caused by the rotation of the shaft (3). The angle sensor (5.1) comprises a plurality of GMR elements, and the plurality of GMR elements are connected to form a Wheatstone bridge structure.

3. The electric compressor position identification device according to claim 1, characterized in that: The PCBA (5) is fastened to the second housing (4) by means of bolts.

4. The electric compressor position identification device according to claim 1, characterized in that: The second shell (4) is made of metal or plastic.

5. The electric compressor position identification device according to claim 1, characterized in that: A sealing device capable of maintaining sealing at a pressure of 20 KPA is provided between the first shell (1) and the second shell (4).

6. The electric compressor position identification device according to claim 1, characterized in that: The shaft (3) is provided with a groove, and the magnet (3.1) is embedded in the groove of the shaft (3).

7. A method for identifying a position of an electric compressor according to any one of claims 1 to 6, characterized in that: include: Get the actual angle value detected by the angle sensor; According to the actual angle value, the original value of the angle sensor is calculated; Calculating the angle position of the electric compressor rotor according to the original value of the angle sensor; The stator current is regulated by the angular position of the electric compressor rotor, thereby controlling the torque and adjusting the speed.

8. The identification method of the electric compressor position identification device according to claim 7, characterized in that: The angle sensor original value is calculated based on the actual angle value, and the formula is as follows: ； in, is the original value of the angle sensor, N The number of bits of the actual angle value. b Indicates the actual angle value; Indicates the number of digits in the summation formula, Indicates the highest bit. Indicates the value of the highest bit of the actual angle value. Indicates the actual angle value to be summed.

9. The identification method of the electric compressor position identification device according to claim 8, characterized in that: The angle position of the electric compressor rotor is calculated based on the original value of the angle sensor, and the formula is as follows: ； in, Indicates the angular position of the electric compressor rotor.

10. The identification method of the electric compressor position identification device according to claim 7, characterized in that: The method of regulating the stator current by adjusting the angular position of the electric compressor rotor, thereby controlling the torque and adjusting the speed, includes: Calculate the electrical angle of the electric compressor rotor based on the angular position of the electric compressor rotor , where the electrical angle of the electric compressor rotor is equal to the electric compressor rotor angular position multiplied by the number of pole pairs of the motor; Using Clarke transformation, the obtained stator current ( , , ), transformed to the stator stationary coordinate system (α-β), the formula is as follows: ； The electrical angle of the electric compressor rotor Perform Park transformation to transform the current component ( , ) is transformed into the rotating coordinate system (dq), the formula is as follows: ； Among them, in the dq coordinate system, represents the magnetic flux component, represents the torque component; Use PI controller to regulate and Error, generate the corresponding d-axis and q-axis voltage instructions and ; The voltage command and To transform from the dq rotating coordinate system back to the stationary α-β coordinate system, use the inverse Park transform, the formula is as follows: ； in, and is the transformed voltage instruction; The converted voltage command and , the required three-phase voltage waveform is generated on the stator, thereby controlling the torque and adjusting the speed.

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