A method for online detection of the number of pole pairs of a permanent magnet synchronous motor and a range hood

Abstract

The present invention relates to an online detection method for the number of pole pairs of a permanent magnet synchronous motor, comprising the following steps: S1, for each known number of pole pairs n i The motor samples to be used are controlled to perform electric speed detection work with the production line load to obtain the corresponding electric speed data w ei , and then determine the electrical speed calibration value w of each motor sample ei And store; S2, for the motor whose pole pair number is to be determined on the production line, under the condition that the initial speed of the motor V≤Vmin, control the electric speed detection work, and then obtain the electric speed data w of the motor ed ; Where Vmin is the set small speed threshold; S3, w ed And the electrical speed calibration value w of each motor sample ei Comparative calculation is performed to determine the corresponding pole pair number data n of the motor. The method has low cost, high accuracy and high automation for detecting the pole pair number of the motor. The present invention also relates to a range hood using the permanent magnet synchronous motor pole pair number online detection method.

Description

Technical Field

[0001] The invention relates to an online detection method for the number of pole pairs of a permanent magnet synchronous motor, and also relates to a range hood using the online detection method for the number of pole pairs of a permanent magnet synchronous motor. Background Art

[0002] Permanent magnet synchronous motor (also called PMSM) has the advantages of high efficiency, small size and low noise, and is widely used in range hoods. The key operating parameters of range hoods, such as air volume, noise, and static pressure, are related to the mechanical speed of PMSM. m is closely related, while the drive control of PMSM can only identify the electrical speed ω e , and ω e =ω m *P n , where P n is the number of pole pairs. Therefore, in P n When the corresponding mechanical speed ω is known, the corresponding mechanical speed ω can be easily obtained. m , thereby controlling the working parameters of the range hood. However, due to different motor manufacturers, the manufacturing parameters P n Different, so the motor pole number P is required n Identification detection.

[0003] When the same range hood uses motors with different pole pairs, the pole pair number also needs to be identified in advance, otherwise the mechanical angular velocity calculation will be inaccurate, resulting in the range hood air volume / noise being unqualified. In addition, the motor manufacturer can only be determined when the range hood is assembled on the production line, and the motor driver board cannot pre-set the pole pair number information. Therefore, the motor pole pair number P needs to be determined when the range hood is assembled. n Factory identification test.

[0004] The number of motor pole pairs currently used is P n There are generally two technical solutions for identification:

[0005] Technology 1: Identify and send motor parameters based on hardware dip switches, that is, when the IO port detects that the dip switch is at a high level, the number of motor pole pairs is m; when the IO port detects that the dip switch is at a low level, the number of motor pole pairs is n. This technical solution requires the support of hardware circuits and is costly; in addition, production line workers need to be trained to dial the code according to different motors, which relies on manual work and has a high error rate.

[0006] Technology 2: Use external detection device to obtain the mechanical angle θ of the motor m / Mechanical speed ω m , and the electrical angle θ given in the program e / Electric speedω e / Electrical frequency comparison f e, obtain the pole pair number information, such as the patent applications CN201710807927.X, CN201811587524.X, CN201911343055.1, and CN201911343055.1 all use this technical solution to detect the number of motor pole pairs. However, the use of this technical solution to detect the number of motor pole pairs requires an external speed detection device. After the pole pair number information is obtained after the detection, the pole pair number of the driver board can be set. However, program burning on the production line will slow down the production line process and the operation is complicated; that is, this solution cannot perform online identification. Summary of the invention

[0007] The first technical problem to be solved by the present invention is to provide a method for online detection of the number of pole pairs of a permanent magnet synchronous motor with low cost, high accuracy and high automation in view of the above-mentioned prior art.

[0008] The second technical problem to be solved by the present invention is to provide a range hood using the above-mentioned permanent magnet synchronous motor pole pair number online detection method in view of the above-mentioned prior art.

[0009] The technical solution adopted by the present invention to solve the above-mentioned first technical problem is: an online detection method for the number of pole pairs of a permanent magnet synchronous motor, characterized in that it comprises the following steps:

[0010] S1, for each known pole pair number n i The motor samples to be used are controlled to perform electric speed detection work with the production line load to obtain the corresponding electric speed data w ei , and then determine the electrical speed calibration value w of each motor sample ei And store them, where i is a positive integer, i represents the motor sample number;

[0011] S2. For the motor whose pole pair number is to be determined on the production line, under the condition that the initial speed of the motor V≤Vmin, the electric speed detection work is controlled to obtain the electric speed data w of the motor. ed ; Where Vmin is the set minimum speed threshold;

[0012] S3, w ed And the electrical speed calibration value w of each motor sample ei Compare and calculate to determine the corresponding pole pair number data n of the motor.

[0013] The calculation is simple. In S3, calculate Δw ei =|w ed -w ei |;

[0014] Get Δw ei The motor sample number x corresponds to the minimum value in , and then the number of motor pole pairs n is determined to be nx .

[0015] Preferably, in S2, the initial speed V of a motor with a to-be-determined number of pole pairs on the production line is detected and obtained. If V≤Vmin, the control directly performs the electric speed detection work of the current motor, and then obtains the electric speed data w of the current motor. ed If V>Vmin, the current motor is controlled to brake. After the current motor stops rotating, the current single machine is controlled to start with constant torque, and then the electric speed detection of the current motor is performed.

[0016] Simply and accurately, the electrical speed detection operation includes the following steps:

[0017] S100, obtaining the initial speed of the motor;

[0018] S200, under the condition that the initial speed of the motor is not greater than Vmin, controlling the constant torque to drive the motor to rotate;

[0019] S300, after the motor runs stably, control the motor brake and detect the three-phase current of the motor;

[0020] S400, when the three-phase current is stable, detect and obtain the three-phase current I of the motor at a certain time T0 af ,I bf ,I cf , and according to the three-phase current I of the motor af ,I bf ,I cf Make phase judgment;

[0021] S400: In the subsequent process, the three-phase current I′ of the motor detected at time T1 af , I′ bf , I′ cf The corresponding phase is consistent with the phase at time T0, so it is judged that the motor rotor has gone through an electrical cycle T e_period =T1-T0;

[0022] S400, calculate the electrical speed of the motor according to the electrical cycle

[0023] The technical solution adopted by the present invention to solve the above-mentioned second technical problem is: a range hood, including a fan, characterized in that: the motor in the fan adopts a permanent magnet synchronous motor, and when the range hood is on the production line, the number of motor poles in the fan is detected by adopting the above-mentioned permanent magnet synchronous motor pole pair number online detection method.

[0024] Compared with the prior art, the advantages of the present invention are: the online detection method for the number of pole pairs of a permanent magnet synchronous motor in the present invention takes into account the principle that when motors with different pole pairs have the same mechanical speed, the electrical angular velocity is different; the principle that when the same torque input and the motor load are the same, the motor mechanical speed is the same; and the number of pole pairs of the permanent magnet synchronous motor is obtained online. The online detection method for the number of pole pairs of a permanent magnet synchronous motor has high accuracy and automation, avoids manual work, does not require a dial switch and its peripheral circuits, and reduces the detection cost.

[0025] For range hoods that apply the permanent magnet synchronous motor pole pair number online detection method, when determining the motor pair number of the motor in the range hood on the production line, it can automatically complete the determination of the pole pair number through simple motor control, which is more intelligent, reduces the detection cost, and reduces the difficulty of operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Flow chart of the method for online detection of the number of pole pairs of a permanent magnet synchronous motor in an embodiment of the present invention.

[0027] Figure 2 Flow chart of the electric speed detection working method in an embodiment of the present invention. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below with reference to the accompanying drawings.

[0029] The mechanical speed of the PMSM motor ω m With electrical speed ω e There is the following relationship: m *P n =ω e , where P n is the pole pair number.

[0030] When two PMSM motors A and B with different pole pairs have similar friction coefficients and the same moment of inertia (i.e. the same load), and the same torque input is used to start, the mechanical speed ω is m same.

[0031] Therefore, when motors A and B, with the same pole pairs of m and n and the same load, start with the same torque and in the same time, the following relationship exists: in is the mechanical speed of motor A, is the mechanical speed of motor B, m is the number of pole pairs of motor A, n is the number of pole pairs of motor B, is the electrical speed of motor A, is the electrical speed of motor B.

[0032] Therefore, the following relationship can be derived: Right now and The difference exists because the pole pairs m and n are different.

[0033] When producing a product with a motor, several motors with different known pole pairs can be used. The number of pole pairs of the motor in each product needs to be determined on the production line.

[0034] like Figure 1 As shown, the method for online detection of the number of pole pairs of a permanent magnet synchronous motor in this embodiment includes the following steps.

[0035] S1. Outside the production line, first of all the known pole pairs n i The electric speed value of the motor samples to be used is calibrated for use in determining the number of motor poles in each product on the production line.

[0036] Specifically, for each known pole pair number n i The motor samples to be used are controlled to perform electric speed detection work with the production line load to obtain the corresponding electric speed data w ei The electric speed detection work is carried out using the following method.

[0037] The electrical speed data w of each motor sample is obtained ei , determined as the electrical speed calibration value w of each motor sample ei And store it in the working system of the production line for use in the detection of the number of motor pole pairs in each product, where i is a positive integer and i represents the motor sample number. If there are two motor samples to be used, the electrical speed data w of the two motor samples are obtained respectively. e1 and w e2 , and the electrical speed data w e1 and w e2 The pole pairs of the corresponding motor samples are n1 and n2 respectively.

[0038] S2. For each motor with a to-be-determined number of pole pairs on the production line, the load of the motor remains basically fixed, that is, the aforementioned production line load.

[0039] For each motor on the production line whose pole pair number is to be determined, the control performs the electrical speed detection work under the condition that the initial speed of the motor V≤Vmin. Where Vmin is the set small speed threshold, which is a very small speed value, that is, when the motor is basically in a zero speed state, the control performs the electrical speed detection work of the motor, so that it can be in the same working state as when the motor sample detects the electrical speed, that is, it can be in the same mechanical speed state. Based on the above principle, the pole pair number can be determined according to the electrical speed data.

[0040] Based on the motor's electrical speed detection work, the motor's electrical speed data w is obtaineded .

[0041] Since the speed of the motor on the production line is uncertain when the electric speed detection is required, the initial speed V of the motor with a to-be-determined number of pole pairs on the production line is first detected and obtained. The initial speed is the mechanical speed of the motor, and the initial speed can be obtained by various methods in the prior art. If V≤Vmin, the control directly performs the electric speed detection of the current motor, and then obtains the electric speed data w of the current motor. ed If V>Vmin, the current motor is controlled to brake, and after the current motor stops rotating, the current single machine is controlled to start with constant torque, and then the electric speed detection of the current motor is performed.

[0042] S3, w ed And the electrical speed calibration value w of each motor sample ei Compare and calculate to determine the corresponding pole pair number data n of the motor. Specifically, calculate Δw ei =|w ed -w ei |; Get Δw ei The motor sample number x, x∈i, corresponding to the minimum value in, is then determined to be n. x .

[0043] like Figure 2 As shown, the aforementioned electric speed detection work specifically includes the following steps:

[0044] S100, obtaining the initial speed of the motor;

[0045] S200, under the condition that the initial speed of the motor is not greater than Vmin, controlling the constant torque to drive the motor to rotate;

[0046] S300, after the motor runs stably, that is, after the PWM output duty cycle is fixed, the motor brake is controlled and the three-phase current of the motor is detected; by using the brake, the three-phase current cycle can be detected to determine the time taken for one electric cycle / electrical speed;

[0047] S400, when the three-phase current is stable, detect and obtain the three-phase current I of the motor at a certain time T0 af ,I bf ,I cf , and according to the three-phase current I of the motor af ,I bf ,I cf Make phase judgment;

[0048] S400: In the subsequent process, the three-phase current I′ of the motor detected at time T1 af , I′ bf , I′ cfThe corresponding phase is consistent with the phase at time T0, so it is judged that the motor rotor has gone through an electrical cycle T e_period =T1-T0;

[0049] S400, calculate the electrical speed of the motor according to the electrical cycle When the electric speed detection method is used for motor samples, the corresponding detection data obtained is the electric speed data w ei When the electric speed detection method is used for the motor whose pole pair number is to be determined on the production line, the corresponding detection data is the electric speed data w ed .

[0050] Since the motor sample to be used is usually in a stationary state when the electrical speed detection work is required, that is, the initial speed (mechanical speed) of the motor sample is 0, it starts to work with constant torque from the stationary state. As for the motor whose pole pair number is to be determined on the production line, since the mechanical speed of the motor is not determined when the electrical speed detection work is required, the method in S2 is adopted, so that the motor whose pole pair number is to be determined on the production line is started with constant torque in a state where the initial speed is not greater than Vmin or in a stationary state, and then maintains a mechanical speed condition that is almost consistent with that when the motor sample is subjected to electrical speed detection.

[0051] In this way, the online detection method for the pole pair number of a permanent magnet synchronous motor in the present invention takes into account the principle that when motors with different pole pairs have the same mechanical speed, the electrical angular velocity is different; and uses the principle that when the same torque input and the motor load are the same, the motor mechanical speed is the same; and then the pole pair number of the permanent magnet synchronous motor is obtained online. The online detection method for the pole pair number of a permanent magnet synchronous motor obtains the motor pole pair number with high accuracy and automation, avoids manual work, does not require a dial switch and its peripheral circuits, and reduces the detection cost.

[0052] The present invention also relates to a range hood, including a fan, wherein the motor in the fan adopts a permanent magnet synchronous motor, and when the range hood is on the production line, the detection of the number of motor poles in the fan adopts the above-mentioned method for online detection of the number of poles of the permanent magnet synchronous motor. On the production line, after the pole pair data of the motor is obtained, the pole pair data is written into the control system of the range hood.

[0053] For range hoods that apply the permanent magnet synchronous motor pole pair number online detection method, when determining the motor pair number of the motor in the range hood on the production line, the pole pair number can be automatically determined through simple motor control, which is more intelligent, reduces the detection cost, and reduces the difficulty of operation.

Claims

1. A method for online detection of the number of pole pairs of a permanent magnet synchronous motor, characterized in that: The following steps are involved: S1, for each known pole pair number n i The motor samples to be used are controlled to perform electric speed detection work with the production line load to obtain the corresponding electric speed data w ei , and then determine the electrical speed calibration value w of each motor sample ei And store them, where i is a positive integer, i represents the motor sample number; S2. For the motor whose pole pair number is to be determined on the production line, under the condition that the initial speed of the motor V≤Vmin, the electric speed detection work is controlled to obtain the electric speed data w of the motor. ed ; Where Vmin is the set minimum speed threshold; S3, w ed And the electrical speed calibration value w of each motor sample ei Compare and calculate to determine the corresponding pole pair number data n of the motor.

2. The method for online detection of the number of pole pairs of a permanent magnet synchronous motor according to claim 1, characterized in that: In S3, Δw is calculated ei =|w ed -w ei |; Get Δw ei The motor sample number x corresponds to the minimum value in , and then the number of motor pole pairs n is determined to be n x .

3. The method for online detection of the number of pole pairs of a permanent magnet synchronous motor according to claim 1, characterized in that: In S2, the initial speed V of the motor with the number of pole pairs to be determined on the production line is detected and obtained. If V≤Vmin, the control directly performs the electric speed detection of the current motor, and then obtains the electric speed data w of the current motor. ed If V>Vmin, the current motor is controlled to brake. After the current motor stops rotating, the current single machine is controlled to start with constant torque, and then the electric speed detection of the current motor is performed.

4. The method for online detection of the number of pole pairs of a permanent magnet synchronous motor according to any one of claims 1 to 3, characterized in that: The electric speed detection work comprises the following steps: S100, obtaining the initial speed of the motor; S200, under the condition that the initial speed of the motor is not greater than Vmin, controlling the constant torque to drive the motor to rotate; S300, after the motor runs stably, control the motor brake and detect the three-phase current of the motor; S400, when the three-phase current is stable, detect and obtain the three-phase current I of the motor at a certain time T0 af ,I bf ,I cf , and according to the three-phase current I of the motor af ,I bf ,I cf Make phase judgment; S400: In the subsequent process, the three-phase current I′ of the motor detected at time T1 af , I′ bf , I′ cf The corresponding phase is consistent with the phase at time T0, so it is judged that the motor rotor has gone through an electrical cycle T e_period =T1-T0; S400, calculate the electrical speed of the motor according to the electrical cycle 5. A range hood, comprising a fan, characterized in that: The motor in the fan adopts a permanent magnet synchronous motor. When the range hood is on the production line, the number of motor pole pairs in the fan is detected by the online detection method for the number of permanent magnet synchronous motor pole pairs as described in any one of claims 1 to 4.

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