A compressor pole pair number online identification method, system and storage medium

Abstract

The present application relates to a kind of compressor pole pair number online identification method, system and storage medium.The method includes: S1, when compressor operates at preset speed, the periodically varying mechanical load signal of compressor is obtained by load observer.Preset speed is less than normal working speed.S2, mechanical frequency is calculated according to mechanical load signal.S3, the pole pair number of compressor is calculated according to mechanical frequency.The present application can be used without changing hardware, using the periodically varying signal of load observer to extract periodic variation signal to identify the pole pair number of different motor, can self-adapting match compressor, effectively improve the intelligent degree of matching compressor, simplify debugging step, effectively reduce the difficulty and complexity of self-adapting match compressor, improve development efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of compressors, in particular to a compressor pole pair number online identification method, system and storage medium. BACKGROUND

[0002] In the current variable frequency compressor control field, in order to solve the problems of insufficient intelligence of 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 is gradually enriched and mature. In the application of variable frequency compressor, speed control is mainly used, and pole pair number is an essential parameter. However, most of the researches or products only identify phase resistance, phase inductance, permanent magnet flux linkage and moment of inertia, and ignore the identification of pole pair number. The related technology usually sets the initial value of the pole pair number, and different compressors with different pole pair numbers need to set different initial values of the pole pair number, which increases the complexity. SUMMARY

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

[0004] The technical scheme adopted by the present application to solve the technical problem is: a compressor pole pair number online identification method, the method comprising the following steps:

[0005] S1, when the compressor runs at a preset speed, obtaining a periodically varying mechanical load signal of the compressor through a load observer; the preset speed is less than the normal working speed;

[0006] S2, calculating a mechanical frequency according to the mechanical load signal;

[0007] S3, calculating the pole pair number of the compressor according to the mechanical frequency.

[0008] Further, in the compressor pole pair number online identification method, the compressor comprises a motor driving a load, and step S1 comprises:

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

[0010] S12, operating 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 number online identification method, the load observer comprises a PI controller, and step S12 comprises:

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

[0013] The error of 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 the load observer.

[0014] Further, in the compressor pole pair number online identification method, the preset coefficient includes a torque current coefficient, a moment of inertia and a rotor friction coefficient of the compressor.

[0015] Further, in the compressor pole pair number online identification method, the load observer calculates the current mechanical load signal according to the following formula:

[0016] (I q -TLo1)*Kt / (JS+bm)=ω0

[0017] (ω0-ω)*Kp+(ω0-ω)*Ki / S=TLo2

[0018] wherein 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, step S2 includes:

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

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

[0022] The mechanical load signal is sampled, digitally filtered, phase detected and phase adjusted by using the digital phase-locked loop to obtain the mechanical frequency.

[0023] Further, in the compressor pole pair number online identification method, 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 application further provides a variable frequency compressor system, which comprises a variable frequency compressor and a drive control module connected therewith, and the drive control module is used for identifying the pole pair number of the variable frequency compressor by using the compressor pole pair number online identification method.

[0026] In addition, the application further provides a computer readable storage medium, which 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.

[0027] The compressor pole pair number online identification method, system and storage medium have the following beneficial effects: the application can identify the pole pair number of different motors by using the load observer to extract the periodic change signal according to the load periodic change rule of the compressor at a low speed without changing the hardware, can adaptively match the compressor, effectively improves the intelligent degree of the matched compressor, simplifies the debugging steps, reduces the difficulty and complexity of adaptively matching the compressor, and improves the development efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0028] The application will be further described below in combination with the drawings and embodiments, and the drawings are as follows:

[0029] Figure 1 is a flowchart of the compressor pole pair number online identification method provided by the embodiment of the application;

[0030] Figure 2 is a flowchart of the compressor pole pair number online identification method provided by the embodiment of the application;

[0031] Figure 3 is a flowchart of the compressor pole pair number online identification method provided by the embodiment of the application;

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

[0033] In order to have a clearer understanding of the technical features, objects and effects of the application, the specific embodiments of the application will be described in detail with reference to the drawings. In the following description, it should be understood that the directions or position relationships indicated by "front", "back", "upper", "lower", "left", "right", "vertical", "horizontal", "vertical", "horizontal", "top", "bottom", "inner", "outer", "head", "tail" and the like are based on the directions or position relationships shown in the drawings, are constructed and operated in a particular direction, and are only for the convenience of describing the technical solutions, and cannot be understood as indicating that the devices or elements must have a particular direction, therefore, it cannot be understood as a limitation on the application.

[0034] It should also be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing", "setting" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements or the interaction relationship between two elements. When an element is referred to as "on" or "below" another element, the element can be "directly" or "indirectly" above the other element, or there can be one or more intervening elements. The terms "first", "second", "third" and the like are only for the convenience of describing the technical solutions, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features with "first", "second", "third" and the like can be explicitly or implicitly included one or more of the features. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0035] In the following description, specific details such as specific system structures, techniques, etc. are presented in order to thoroughly understand the embodiments of the present application. However, it should be clear to those skilled in the art that the present application can also 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 avoid unnecessary details that hinder the description of the present application.

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

[0037] S1, when the compressor operates at a preset speed, the periodically varying mechanical load signal of the compressor is obtained by the load observer. The preset speed is less than the normal operating speed. Alternatively, the preset speed can be the minimum speed of the compressor, of course, the compressor can also be controlled to operate below the minimum speed, as long as the mechanical vibration can be generated to enable the load observer to obtain the periodically varying mechanical load signal of the compressor. For example, 20% of the maximum speed of the motor can be used as the preset speed. The load observer of the present application is a closed-loop controller for observing the mechanical load signal.

[0038] It can be understood that controlling the compressor to operate at the minimum speed or below the minimum speed, in the internal mechanical structure of the compressor, the crank rod of the compressed gas will complete the function of changing the circular motion of the motor rotor into the linear reciprocating motion of the push rod, and the motor rotor will generate mechanical vibration due to the centrifugal action of the crank rod load.

[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 rotation in the compressor.

[0040] S3, calculate the pole pair number of the compressor according to the mechanical frequency.

[0041] It can be understood that the pole pair number (i.e. the pole pair number, the number of magnetic poles in the motor) is an inherent property of the motor, and different motors correspond to different pole pair numbers. Since the software / program (such as the control program) needs to adapt to different motors, by identifying the pole pair number of different motors, the software can completely adapt to match different compressors. Specifically, the software matching the compressor means that the software can well drive the compressor, which requires related motor parameters (including resistance, inductance, back electromotive force coefficient, pole pair number, etc.). Generally, the motor parameters are fixed in the software, which is a special software. Therefore, without fixing the motor parameters, the software can identify the motor parameters through self-learning, which can match many types of motors, and the software is more universal. The pole pair number self-learning proposed in the present scheme, combined with the self-learning of the motor parameters other than the pole pair number, can completely realize the adaptive matching of different types of compressors.

[0042] The present embodiment can adaptively match the compressor without changing the hardware, use the load observer to extract the periodic change signal to identify the pole pair number of different motors, effectively improve the intelligent degree of matching the compressor, simplify the debugging steps, reduce the difficulty and complexity of adaptive matching the compressor, and improve the development efficiency.

[0043] In some embodiments, with reference to Figure 2 , step S1 includes: S11, when the compressor operates at a preset speed, obtaining the actual torque current and the actual electrical angular velocity of the motor thereof. S12, the actual torque current and the actual electrical angular velocity are operated through the load observer to obtain the mechanical load signal. It can be understood that the actual torque current is the current torque current, and the actual electrical angular velocity is the current electrical angular velocity. In the present embodiment, the compressor is controlled to operate at a preset speed, and the current torque current and the current electrical angular velocity of the motor of the compressor are obtained. Then the current torque current and the current electrical angular velocity are operated through the load observer to obtain the mechanical load signal. Then the mechanical frequency is calculated according to the mechanical load signal. The pole pair number of the compressor is calculated based on the mechanical frequency.

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

[0045] The embodiment can extract a period change signal by using a load observer to identify the pole pair number without changing or adding hardware, and can identify the pole pair number online when the compressor is running, so as to adaptively match the compressor, effectively improve the intelligent degree of the matched compressor, simplify the debugging steps, effectively reduce the difficulty and complexity of the adaptive matching of the compressor, improve the development efficiency, and save the cost. Moreover, the identification process takes very short time, which can be completed within a few seconds, and does not affect the user experience.

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

[0047] S121, calculating an internal estimated electrical angular velocity according to the error between the actual torque current and the first mechanical load signal and a preset coefficient. The first mechanical load signal is the mechanical load signal obtained by the load observer in the last operation. S122, calculating the second mechanical load signal by the PI controller according to the error between the actual electrical angular velocity and the internal estimated electrical angular velocity. 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 run at a preset speed, and the current torque current and the current electrical angular velocity of the motor of the compressor are obtained. The internal estimated electrical angular velocity is calculated according to the error between the current torque current and the mechanical load signal estimated by the load observer in the last time and a preset coefficient, and the current mechanical load signal is calculated by the PI controller according to the error between the current electrical angular velocity and the internal estimated electrical angular velocity. Then, the mechanical frequency is calculated according to the current mechanical load signal, and the pole pair number of the compressor is calculated based on the mechanical frequency.

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

[0049] Optionally, the preset coefficient includes a torque current coefficient of the compressor, a moment of inertia of the compressor, and a rotor friction coefficient of the compressor.

[0050] The embodiment can adaptively match the compressor without changing or adding hardware, effectively improve the intelligent degree of the matched compressor, simplify the debugging steps, effectively reduce the difficulty and complexity of the adaptive matching of the compressor, improve the development efficiency, save the cost, and complete the identification process in a few seconds without affecting the user experience.

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

[0052] (I q -TLo1)*Kt / (JS+bm)=ω0

[0053] (ω0-ω)*Kp+(ω0-ω)*Ki / S=TLo2

[0054] wherein, 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 last 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 rotational 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 a control system, the transfer function is used to express the response of the system to the input signal. S is a complex variable, representing the frequency in the Laplace transform domain. It is usually represented 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] The embodiment can adaptively match the compressor without changing or adding hardware, effectively improve the intelligent degree of the matched compressor, simplify the debugging steps, effectively reduce the difficulty and complexity of the adaptive matching of the compressor, improve the development efficiency, save the cost, and complete the identification process in a few seconds without affecting the user experience.

[0057] In some embodiments, step S2 comprises determining the mechanical frequency from the mechanical load signal by using a digital phase-locked loop. Specifically, the compressor pole pair number online identification method of the present 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 according to the error between the current torque current and the mechanical load signal estimated by the load observer last time and the related preset coefficient, 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 digital phase-locked loop is used to sample, digitally filter, phase detect and phase adjust the current mechanical load signal to obtain the mechanical frequency, and the pole pair number of the compressor is calculated based on the mechanical frequency. Specifically, the pole pair number of the compressor is calculated according to the mechanical frequency and the actual electrical angular velocity. It can be understood that the pole pair number = mechanical frequency * 2π / actual electrical angular velocity.

[0058] It can be understood that the digital phase-locked loop (DPLL for short) realizes accurate tracking and control of the frequency and phase of the input signal through a series of processes such as sampling, digital filtering, phase detection and adjustment of the input signal. The digital phase-locked loop is a mature algorithm module, and the specific algorithm process can refer to related technologies, which will not be described here. Alternatively, the digital phase-locked loop can also be replaced by other modules capable of determining the signal frequency (mechanical frequency).

[0059] The present embodiment can use the load observer to extract the periodic variation signal to identify the pole pair number without changing or adding hardware, and can adaptively match the compressor, effectively improve the intelligent degree of the matched compressor, simplify the debugging steps, effectively reduce the difficulty and complexity of the adaptive matching of the compressor, improve the development efficiency, and save the cost. Moreover, the identification process takes very short time, which can be completed within a few seconds, and does not affect the user experience.

[0060] In another preferred embodiment, the variable frequency compressor system of the present embodiment comprises a variable frequency compressor and a drive control module connected thereto, and the drive control module uses the compressor pole pair number online identification method of the above-mentioned embodiments to identify the pole pair number of the variable frequency compressor.

[0061] The present embodiment can use the load observer to extract the periodic variation signal to identify the pole pair number of different motors without changing the hardware, and can adaptively match the compressor, effectively improve the intelligent degree of the matched compressor, simplify the debugging steps, effectively reduce the difficulty and complexity of the adaptive matching of the compressor, and improve the development efficiency.

[0062] In another preferred embodiment, the computer readable storage medium of the present embodiment stores a computer program adapted to be loaded by a processor to execute the steps of the compressor pole pair number online identification method of the above-mentioned embodiment.

[0063] The present embodiment can extract a periodic variation signal using a load observer to identify the pole pair number of different motors without changing hardware, using the load periodic variation law of the compressor at low speed, can adaptively match the compressor, effectively improves the intelligent degree of the matched compressor, simplifies the debugging steps, effectively reduces the difficulty and complexity of the adaptive matching of the compressor, and improves the development efficiency.

[0064] The computer readable storage medium of the present application can be a U disk, a mobile hard disk, a read-only memory (Read-Only Memory, ROM), a magnetic disk or an optical disk, and various computer readable storage media that can store program codes.

[0065] The processor of the present application 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 can be a central processing unit (Central Processing Unit, CPU), and the processor can also be other general-purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), ready programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. Among them, the general-purpose processor can be a microprocessor, or the processor can also be any conventional processor, etc.

[0066] The skilled person can further realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be realized in electronic hardware, computer software or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the components and steps of the examples have been described in the above description in general terms. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0067] The steps of a method or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module can reside in random access memory (RAM), flash memory, read-only memory (ROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, hard disk can be used as a storage medium.

[0068] It can be understood that the above embodiments only express the preferred embodiments of the present application, which are described in a more specific and detailed manner, but should not be construed as a limitation to the patent scope of the present application. It should be noted that the above technical features can be freely combined without departing from the concept of the present application, and several modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, any equivalent transformation and modification within the scope of the claims of the present application should belong to the scope of the claims of the present application.

Claims

1. A method for online identification of pole pair number of a compressor, characterized in that, The method comprises the following steps: S1, obtaining a periodically varying mechanical load signal of the compressor by a load observer when the compressor operates at a preset speed; the preset speed is less than a normal operating speed; S2, calculating a mechanical frequency according to the mechanical load signal; S3, calculating a pole pair number of the compressor according to the mechanical frequency; The compressor comprises a motor driving a load, and step S1 comprises: S11, obtaining an actual torque current and an actual electrical angular velocity of the motor of the compressor when the compressor operates at the preset speed; S12, operating the actual torque current and the actual electrical angular velocity by the load observer to obtain the mechanical load signal; The load observer comprises a PI controller, and step S12 comprises: calculating an internal estimated electrical angular velocity according to an error between the actual torque current and a first mechanical load signal and a preset coefficient; wherein the first mechanical load signal is a mechanical load signal obtained by the load observer in a previous operation; and the preset coefficient comprises a torque current coefficient, a moment of inertia and a rotor friction coefficient of the compressor; calculating a second mechanical load signal by the PI controller according to an error between the actual electrical angular velocity and the internal estimated electrical angular velocity; wherein the second mechanical load signal is a current mechanical load signal obtained by the load observer; The load observer calculates the current mechanical load signal by the following formula: wherein, is the actual torque current, is the internal estimated electrical angular velocity, is the actual electrical angular velocity, is the first mechanical load signal, is the second mechanical load signal, is the torque current coefficient of the compressor, is the moment of inertia of the compressor, is a complex variable, is the rotor friction coefficient of the compressor, is the proportional coefficient of the PI controller, is the integral coefficient of the PI controller.

2. The method of claim 1, wherein, Step S2 comprises: determining the mechanical frequency from the mechanical load signal by a digital phase-locked loop.

3. The method of claim 2, wherein, Step S2 comprises: sampling, digitally filtering, phase detecting and phase adjusting the mechanical load signal by the digital phase-locked loop to obtain the mechanical frequency.

4. The method of claim 1, wherein, Step S3 comprises: calculating the pole pair number according to the mechanical frequency and the actual electrical angular velocity.

5. A variable frequency compressor system characterized by, The variable frequency compressor system comprises a variable frequency compressor and a driving control module connected thereto, and the driving control module adopts the compressor pole pair number online identification method according to any one of claims 1 to 4 to identify the pole pair number of the variable frequency compressor.

6. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the computer program is adapted to be loaded by a processor to execute the steps of the compressor pole pair number online identification method according to any one of claims 1 to 4.

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