Online identification method and system for number of pole pairs of compressor and storage medium

Abstract

The invention relates to a compressor pole pair number online identification method and system and a storage medium. The method comprises the following steps: S1, when the compressor operates at a preset rotating speed, obtaining a periodically changing mechanical load signal of the compressor through a load observer; the preset rotating speed is smaller than normal working rotating speed. And S2, calculating the mechanical frequency according to the mechanical load signal. And S3, calculating the number of pole pairs of the compressor according to the mechanical frequency. Under the condition that hardware is not changed, the periodic change rule of the load of the compressor at the low rotating speed is utilized, the periodic change signals are extracted through the load observer to identify the number of pole pairs of different motors, the compressor can be matched in a self-adaptive mode, the intelligent degree of the matched compressor is effectively improved, debugging steps are simplified, and the debugging efficiency is improved. The difficulty and complexity of self-adaptive matching of the compressor are effectively reduced, and the development efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of compressors, and in particular to a method, system and storage medium for online identification of compressor pole pairs. Background Art

[0002] At present, in the field of variable frequency compressor control, in order to solve the problems of insufficient controller matching, complex debugging, and low development efficiency caused by the large number of compressor models in engineering applications, the research on motor parameter identification has gradually become richer and more mature. Speed ​​control is the main application of variable frequency compressors, and the pole pair number is an indispensable parameter. However, most of these studies or products only identify phase resistance, phase inductance, permanent magnet flux linkage, and moment of inertia, while ignoring the identification of pole pairs. Related technologies usually set the initial value of the pole pair number, and compressors with different pole pairs need to set different initial values ​​of the pole pair number, which increases the complexity. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method, system and storage medium for online identification of the pole pair number of a compressor in view of the problem of pole pair number identification.

[0004] The technical solution adopted by the present invention to solve the technical problem is: a method for online identification of compressor pole pairs, the method comprising the following steps:

[0005] S1. When the compressor is running at a preset speed, a mechanical load signal of the compressor periodically changing is obtained through a load observer; the preset speed is lower than the normal working speed;

[0006] S2. Calculate the mechanical frequency according to the mechanical load signal;

[0007] S3. Calculate the number of pole pairs of the compressor according to the mechanical frequency.

[0008] Further, in the compressor pole pair online identification method of the present invention, the compressor includes a motor driving a load, and step S1 includes:

[0009] S11, when the compressor runs at the preset speed, obtaining the actual torque current and actual electrical angular velocity of its motor;

[0010] S12. Calculate the actual torque current and the actual electrical angular velocity through the load observer to obtain the mechanical load signal.

[0011] Further, in the compressor pole pair online identification method of the present invention, the load observer includes a PI controller, and step S12 includes:

[0012] The internal estimated electrical angular velocity is calculated based on the error between the actual torque current and the first mechanical load signal and a preset coefficient; wherein the first mechanical load signal is the mechanical load signal obtained by the previous operation of the load observer;

[0013] The error between the actual electrical angular velocity and the internal estimated electrical angular velocity is calculated by the PI controller to obtain a second mechanical load signal; wherein the second mechanical load signal is a current mechanical load signal obtained by calculation by the load observer.

[0014] Furthermore, in the compressor pole pair number online identification method described in the present invention, the preset coefficients include the torque current coefficient, moment of inertia and rotor friction coefficient of the compressor.

[0015] Furthermore, in the compressor pole pair online identification method of the present invention, the load observer calculates the current mechanical load signal by the following formula:

[0016] (I q -TLo1)*Kt / (JS+bm)=ω0

[0017] (ω0-ω)*Kp+(ω0-ω)*Ki / S=TLo2

[0018] Among them, I q is the actual torque current, ω0 is the internal estimated electrical angular velocity, ω is the actual electrical angular velocity, TLo1 is the first mechanical load signal, TLo2 is the second mechanical load signal, Kt is the torque current coefficient of the compressor, J is the moment of inertia of the compressor, S is a complex variable, bm is the rotor friction coefficient of the compressor, Kp is the proportional coefficient of the PI controller, and Ki is the integral coefficient of the PI controller.

[0019] Further, in the compressor pole pair number online identification method of the present invention, step S2 includes:

[0020] The mechanical frequency is determined from the mechanical load signal using a digital phase locked loop.

[0021] Further, in the compressor pole pair number online identification method of the present invention, step S2 includes:

[0022] The digital phase-locked loop is used to perform sampling, digital filtering, phase detection and phase adjustment processing on the mechanical load signal to obtain the mechanical frequency.

[0023] Further, in the compressor pole pair number online identification method of the present invention, step S3 includes:

[0024] The pole pair number is calculated according to the mechanical frequency and the actual electrical angular velocity.

[0025] In addition, the present invention also provides a variable frequency compressor system, which includes a variable frequency compressor and a drive control module connected thereto, and the drive control module uses the above-mentioned compressor pole pair online identification method to identify the pole pair of the variable frequency compressor.

[0026] In addition, the present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and the computer program is suitable for being loaded by a processor to execute the steps of the above-mentioned compressor pole pair online identification method.

[0027] The implementation of the compressor pole pair number online identification method, system and storage medium of the present invention has the following beneficial effects: the present invention can utilize the load cycle variation law of the compressor at low speed without changing the hardware, and adopt a load observer to extract the cycle variation signal to identify the pole pair number of different motors. It can adaptively match the compressor, effectively improve the intelligence level of matching the compressor, simplify the debugging steps, reduce the difficulty and complexity of adaptively matching the compressor, and improve development efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0029] Figure 1 1 is a flow chart of a method for online identification of compressor pole pairs provided by an embodiment of the present invention;

[0030] Figure 2 1 is a flow chart of a method for online identification of compressor pole pairs provided by an embodiment of the present invention;

[0031] Figure 3 1 is a flow chart of a method for online identification of compressor pole pairs provided by an embodiment of the present invention;

[0032] Figure 4 It is a schematic diagram of the working principle of the load observer provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "back", "up", "down", "left", "right", "longitudinal", "horizontal", "vertical", "horizontal", "top", "bottom", "inside", "outside", "head", "tail", etc. are based on the directions or positional relationships shown in the accompanying drawings, are constructed and operated in a specific direction, and are only for the convenience of describing the present technical solution, rather than indicating that the device or element referred to must have a specific direction, and therefore cannot be understood as a limitation to the present invention.

[0034] It should also be noted that, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected", "fixed", "set" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. When an element is referred to as being "on" or "under" another element, the element can be "directly" or "indirectly" located on the other element, or there may be one or more intermediate elements. The terms "first", "second", "third", etc. are only for the convenience of describing the present technical solution, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", "third", etc. can explicitly or implicitly include one or more of the features. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0035] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0036] In a preferred embodiment, reference Figure 1 The compressor includes a motor driving a load. The online identification method of the compressor pole pair number of this embodiment includes the following steps:

[0037] S1. When the compressor is running at a preset speed, a mechanical load signal of the compressor periodically changes is obtained through a load observer. The preset speed is lower than the normal working speed. As an option, the preset speed can be the minimum speed of the compressor. Of course, the compressor can also be controlled to run below the minimum speed, as long as mechanical vibration can be generated to enable the load observer to obtain a mechanical load signal of the compressor periodically changes. For example, 20% of the maximum speed of the motor can be used as the preset speed. The load observer of the present invention is a closed-loop controller for observing mechanical load signals.

[0038] It can be understood that when the compressor is controlled to operate at the minimum speed or below the minimum speed, in the internal mechanical structure of the compressor, the crankshaft that compresses the gas must complete the function of changing the circular motion of the motor rotor into the linear reciprocating motion of the push rod. The motor rotor will thus be affected by the centrifugal effect of the crankshaft load and produce mechanical vibration.

[0039] S2. Calculate the mechanical frequency according to the mechanical load signal. It should be noted that the mechanical frequency refers to the mechanical motion frequency of the motor rotating in the compressor.

[0040] S3. Calculate the number of pole pairs of the compressor based on the mechanical frequency.

[0041] It can be understood that the number of magnetic pole pairs (also known as the number of pole pairs, the number of magnetic poles in the motor) is an inherent property of the motor. Different motors may have different corresponding numbers of magnetic pole pairs. Since the software / program (such as control program, etc.) needs to adapt to different motors, the software can fully adaptively match different compressors by identifying the number of magnetic pole pairs of different motors. Specifically, software matching compressor means that the software can drive the compressor well, which requires the use of relevant motor parameters (including resistance, inductance, back-electromotive force coefficient, pole pair number, etc.). Generally, the motor parameters are solidified in the software, which is a dedicated software. Then, if the motor parameters are not solidified, the motor parameters can be identified through software self-learning, which can match many types of motors, and the software is therefore more versatile. The pole pair self-learning proposed in this scheme, combined with the self-learning of motor parameters other than pole pairs that have related technical methods, can fully realize adaptive matching of compressors of different models.

[0042] This embodiment can utilize the load cycle variation law of the compressor at low speed, adopt a load observer to extract the cycle variation signal to identify the pole pair number of different motors without changing the hardware. It can adaptively match the compressor, effectively improve the intelligence level of matching the compressor, simplify the debugging steps, reduce the difficulty and complexity of adaptively matching the compressor, and improve development efficiency.

[0043] In some embodiments, reference Figure 2 , step S1 includes: S11, when the compressor runs at a preset speed, the actual torque current and actual electrical angular velocity of its motor are obtained. S12, the actual torque current and the actual electrical angular velocity are calculated by a load observer to obtain a mechanical load signal. It can be understood that the actual torque current is also the current torque current, and the actual electrical angular velocity is also the current electrical angular velocity. In this embodiment, the compressor is controlled to run at a preset speed, and the current torque current and the current electrical angular velocity of the compressor motor are obtained. Then the current torque current and the current electrical angular velocity are calculated by a load observer to obtain a mechanical load signal. The mechanical frequency is then calculated based on the mechanical load signal. The number of pole pairs of the compressor is calculated based on the mechanical frequency.

[0044] It should be noted that the torque current of the present invention refers to the current flowing through the rotor winding in the motor to generate torque. The electrical angular velocity refers to the electrical angle that the motor rotates per unit time during rotation. Specifically, the relationship between the electrical angular velocity and the electrical frequency is: electrical angular velocity = electrical frequency * 2п.

[0045] This embodiment can utilize the load cycle variation law of the compressor at low speed without changing or adding hardware, use the load observer to extract the cycle variation signal to identify the pole pair number, perform online identification when the compressor is running, and can adaptively match the compressor, effectively improve the intelligence level of matching the compressor, simplify the debugging steps, effectively reduce the difficulty and complexity of adaptively matching the compressor, improve development efficiency, and save costs. Moreover, the identification process takes a very short time and can be completed within a few seconds, without affecting the user experience.

[0046] In some embodiments, reference Figure 3 , the load observer includes a PI controller, and step S12 includes:

[0047] S121. Calculate the internal estimated electrical angular velocity based on the error between the actual torque current and the first mechanical load signal and the preset coefficient. The first mechanical load signal is the mechanical load signal obtained by the previous operation of the load observer. S122. Calculate the error between the actual electrical angular velocity and the internal estimated electrical angular velocity through a PI controller to obtain a second mechanical load signal. The second mechanical load signal is the current mechanical load signal obtained by the load observer. It can be understood that in this embodiment, the compressor is controlled to operate at a preset speed to obtain the current torque current and the current electrical angular velocity of the compressor motor. Calculate the internal estimated electrical angular velocity based on the error between the current torque current and the mechanical load signal obtained by the last estimation of the load observer and the preset coefficient, and calculate the error between the current electrical angular velocity and the internal estimated electrical angular velocity through a PI controller to obtain the current mechanical load signal. Next, calculate the mechanical frequency based on the current mechanical load signal, and then calculate the number of pole pairs of the compressor based on the mechanical frequency.

[0048] It can be understood that the load observer of this embodiment is a closed-loop controller, and the output of the load observer can be used as feedback to participate in the internal operation. That is, the mechanical load signal obtained in the previous operation can be used as the feedback of the current operation to participate in the operation, thereby obtaining the current mechanical load signal, thereby continuously updating and iterating.

[0049] Optionally, the preset coefficients include a torque current coefficient of the compressor, a rotational inertia of the compressor, and a rotor friction coefficient of the compressor.

[0050] This embodiment can utilize the load cycle variation law of the compressor at low speed without changing or adding hardware, use the load observer to extract the cycle variation signal to identify the pole pair number, perform online identification when the compressor is running, and can adaptively match the compressor, effectively improve the intelligence level of matching the compressor, simplify the debugging steps, effectively reduce the difficulty and complexity of adaptively matching the compressor, improve development efficiency, and save costs. Moreover, the identification process takes a very short time and can be completed within a few seconds, without affecting the user experience.

[0051] In some embodiments, reference Figure 4 , the load observer calculates the current mechanical load signal through the following formula, that is, in this embodiment, the working principle of the load observer is as follows:

[0052] (I q -TLo1)*Kt / (JS+bm)=ω0

[0053] (ω0-ω)*Kp+(ω0-ω)*Ki / S=TLo2

[0054] Among them, I q is the actual torque current, ω0 is the internal estimated electrical angular velocity, ω is the actual electrical angular velocity, TLo1 is the first mechanical load signal, that is, the mechanical load signal obtained in the previous operation. TLo2 is the second mechanical load signal, that is, the mechanical load signal obtained in the current operation. Kt is the torque current coefficient of the compressor, J is the moment of inertia of the compressor, bm is the rotor friction coefficient of the compressor, Kp is the proportional coefficient of the PI controller, and Ki is the integral coefficient of the PI controller.

[0055] It should be noted that the transfer function is an important tool for describing the relationship between the input and output of a linear time-invariant system. In control systems, the transfer function is used to express the response of the system to the input signal. S is a complex variable that represents the frequency in the Laplace transform domain. It is usually expressed as s=σ+jω, where σ is the real part and ω is the imaginary part, corresponding to the frequency. 1 / S represents an integral operation.

[0056] This embodiment can utilize the load cycle variation law of the compressor at low speed without changing or adding hardware, use the load observer to extract the cycle variation signal to identify the pole pair number, perform online identification when the compressor is running, and can adaptively match the compressor, effectively improve the intelligence level of matching the compressor, simplify the debugging steps, effectively reduce the difficulty and complexity of adaptively matching the compressor, and improve development efficiency. Moreover, the identification process takes a very short time and can be completed within a few seconds, which does not affect the user experience.

[0057] In some embodiments, step S2 includes: determining the mechanical frequency from the mechanical load signal using a digital phase-locked loop. Specifically, the compressor pole pair number online identification method of this embodiment uses a digital phase-locked loop to sample, digitally filter, phase detect and phase adjust the mechanical load signal to obtain the mechanical frequency. In this embodiment, when the compressor is running at a preset speed, the current torque current and the current electrical angular velocity of the motor are obtained. The internal estimated electrical angular velocity is calculated based on the error between the current torque current and the mechanical load signal estimated by the load observer last time and the relevant preset coefficients, and the error between the current electrical angular velocity and the internal estimated electrical angular velocity is calculated by a PI controller to obtain the current mechanical load signal of the motor. Then, the current mechanical load signal is sampled, digitally filtered, phase detected and phase adjusted using a digital phase-locked loop to obtain the mechanical frequency, and then the pole pair number of the compressor is calculated based on the mechanical frequency. Specifically, the pole pair number of the compressor is calculated based on the mechanical frequency and the actual electrical angular velocity. It can be understood that the pole pair number = mechanical frequency * 2п / actual electrical angular velocity.

[0058] It can be understood that the digital phase-locked loop (DPLL) achieves accurate tracking and control of the frequency and phase of the input signal by sampling, digital filtering, phase detection and adjustment of the input signal. The digital phase-locked loop is a mature algorithm module. The specific algorithm processing process can refer to the relevant technology and will not be repeated here. As an option, the digital phase-locked loop can also be replaced by other modules that can determine the signal frequency (mechanical frequency).

[0059] This embodiment can utilize the load cycle variation law of the compressor at low speed without changing or adding hardware, use the load observer to extract the cycle variation signal to identify the pole pair number, perform online identification when the compressor is running, and can adaptively match the compressor, effectively improve the intelligence level of matching the compressor, simplify the debugging steps, effectively reduce the difficulty and complexity of adaptively matching the compressor, improve development efficiency, and save costs. Moreover, the identification process takes a very short time and can be completed within a few seconds, without affecting the user experience.

[0060] In another preferred embodiment, the variable frequency compressor system of this embodiment includes a variable frequency compressor and a drive control module connected thereto, and the drive control module uses the compressor pole pair online identification method of the above embodiment to identify the pole pair of the variable frequency compressor.

[0061] This embodiment can utilize the load cycle variation law of the compressor at low speed, adopt a load observer to extract the cycle variation signal to identify the pole pair number of different motors without changing the hardware. It can adaptively match the compressor, effectively improve the intelligence level of matching the compressor, simplify the debugging steps, effectively reduce the difficulty and complexity of adaptively matching the compressor, and improve development efficiency.

[0062] In another preferred embodiment, the computer-readable storage medium of this embodiment stores a computer program, and the computer program is suitable for being loaded by a processor to execute the steps of the compressor pole pair number online identification method of the above embodiment.

[0063] This embodiment can utilize the load cycle variation law of the compressor at low speed, adopt a load observer to extract the cycle variation signal to identify the pole pair number of different motors without changing the hardware. It can adaptively match the compressor, effectively improve the intelligence level of matching the compressor, simplify the debugging steps, effectively reduce the difficulty and complexity of adaptively matching the compressor, and improve development efficiency.

[0064] The computer-readable storage medium of the present invention can be any computer-readable storage medium that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a magnetic disk, or an optical disk.

[0065] The processor of the present invention is used to provide computing and control capabilities to support the operation of the entire device. It should be understood that in the embodiments of the present application, the processor may be a central processing unit (CPU), and the processor may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. Among them, the general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0066] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0067] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0068] It can be understood that the above embodiments only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, the above technical features can be freely combined without departing from the concept of the present invention, and several deformations and improvements can be made, which all belong to the protection scope of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should belong to the coverage of the claims of the present invention.

Claims

1. A method for online identification of compressor pole pairs, characterized in that: The method comprises the following steps: S1. When the compressor is running at a preset speed, a mechanical load signal of the compressor periodically changing is obtained through a load observer; the preset speed is lower than the normal working speed; S2. Calculate the mechanical frequency according to the mechanical load signal; S3. Calculate the number of pole pairs of the compressor according to the mechanical frequency.

2. The method for online identification of compressor pole pairs according to claim 1, wherein the compressor comprises a motor driving a load, characterized in that: Step S1 includes: S11, when the compressor runs at the preset speed, obtaining the actual torque current and actual electrical angular velocity of its motor; S12. Calculate the actual torque current and the actual electrical angular velocity through the load observer to obtain the mechanical load signal.

3. The method for online identification of compressor pole pairs according to claim 2, characterized in that: The load observer includes a PI controller, and step S12 includes: The internal estimated electrical angular velocity is calculated based on the error between the actual torque current and the first mechanical load signal and a preset coefficient; wherein the first mechanical load signal is the mechanical load signal obtained by the previous operation of the load observer; The error between the actual electrical angular velocity and the internal estimated electrical angular velocity is calculated by the PI controller to obtain a second mechanical load signal; wherein the second mechanical load signal is a current mechanical load signal obtained by calculation by the load observer.

4. The method for online identification of compressor pole pairs according to claim 3, characterized in that: The preset coefficients include the torque current coefficient, the moment of inertia and the rotor friction coefficient of the compressor.

5. The method for online identification of compressor pole pairs according to claim 3, characterized in that: The load observer calculates the current mechanical load signal using the following formula: (I q -TLo1)*Kt / (JS+bm)=ω0 (ω0-ω)*Kp+(ω0-ω)*Ki / S=TLo2 Among them, I q is the actual torque current, ω0 is the internal estimated electrical angular velocity, ω is the actual electrical angular velocity, TLo1 is the first mechanical load signal, TLo2 is the second mechanical load signal, Kt is the torque current coefficient of the compressor, J is the moment of inertia of the compressor, S is a complex variable, bm is the rotor friction coefficient of the compressor, Kp is the proportional coefficient of the PI controller, and Ki is the integral coefficient of the PI controller.

6. The method for online identification of compressor pole pairs according to claim 2, characterized in that: Step S2 includes: The mechanical frequency is determined from the mechanical load signal using a digital phase locked loop.

7. The method for online identification of compressor pole pairs according to claim 6, characterized in that: Step S2 includes: The digital phase-locked loop is used to perform sampling, digital filtering, phase detection and phase adjustment processing on the mechanical load signal to obtain the mechanical frequency.

8. The method for online identification of compressor pole pairs according to claim 2, characterized in that: Step S3 includes: The pole pair number is calculated according to the mechanical frequency and the actual electrical angular velocity.

9. A variable frequency compressor system, characterized in that: The variable frequency compressor system includes a variable frequency compressor and a drive control module connected thereto, and the drive control module uses the compressor pole pair online identification method according to any one of claims 1 to 8 to identify the pole pair of the variable frequency compressor.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and the computer program is suitable for being loaded by a processor to execute the steps of the method for online identification of the number of compressor pole pairs according to any one of claims 1 to 8.

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