Compressor control method, air conditioner and storage medium

Abstract

This invention provides a compressor control method, an air conditioner, and a storage medium. The method includes: acquiring the real-time speed and ideal speed of a motor; performing PI control calculations based on the speed difference between the ideal speed and the real-time speed to obtain an ideal current; acquiring the real-time current of the motor and calculating the current difference between the ideal current and the real-time current; calculating the actual slip of the motor based on the current difference; and adjusting the output frequency of the inverter based on the actual slip. Applying this compressor control method can reduce motor speed fluctuations and improve the working efficiency of the air conditioner compressor.

Description

Technical Field

[0001] This invention relates to the field of compressor technology, specifically to a compressor control method, an air conditioner using the compressor control method, and a computer-readable storage medium using the compressor control method. Background Technology

[0002] The air conditioner compressor is one of the most important components in an air conditioning system. Its main function is to compress low-temperature, low-pressure refrigerant gas into high-temperature, high-pressure gas, thereby driving the entire refrigeration cycle. The compressor is mainly controlled by a frequency converter, which essentially controls the compressor's power by adjusting the frequency of the AC power input to the motor to change the motor's speed.

[0003] In most cases, motor load is not constant. Changes in motor load will affect motor slip, leading to variations in motor speed and thus impacting compressor efficiency. Motor slip is closely related to motor speed; the actual motor speed is determined by both synchronous speed and slip. When slip changes due to load variations, the actual motor speed will also change accordingly. For example, with a constant synchronous speed, if slip increases, it means the rotor's lag relative to the rotating magnetic field increases, thus decreasing the actual motor speed; conversely, if slip decreases, the actual motor speed will increase. For compressors, efficiency is closely related to speed. Different speeds result in different intake and exhaust volumes, as well as varying degrees of internal gas compression. Generally, compressors have an optimal operating speed range. When motor speed deviates from this range due to slip changes caused by load variations, the compressor's intake and exhaust processes may not reach their optimal state, affecting efficiency and leading to problems such as decreased cooling or heating performance and increased energy consumption.

[0004] Therefore, more optimized compressor control methods need to be considered. Summary of the Invention

[0005] The primary objective of this invention is to provide a compressor control method that can reduce motor speed fluctuations and improve the working efficiency of air conditioning compressors.

[0006] The second objective of this invention is to provide an air conditioner that can reduce motor speed fluctuations and improve the working efficiency of the air conditioner compressor.

[0007] A third objective of this invention is to provide a computer-readable storage medium that can reduce motor speed fluctuations and improve the working efficiency of an air conditioning compressor.

[0008] To achieve the aforementioned first objective, the compressor control method provided by the present invention includes: acquiring the real-time speed and ideal speed of the motor; performing PI control calculation based on the speed difference between the ideal speed and the real-time speed to obtain the ideal current; acquiring the real-time current of the motor; calculating the current difference between the ideal current and the real-time current; calculating the actual slip of the motor based on the current difference; and adjusting the output frequency of the frequency converter based on the actual slip.

[0009] As can be seen from the above scheme, the compressor control method of the present invention obtains the ideal current by PI control calculation based on the difference between the real-time motor speed and the ideal speed, and calculates the actual slip based on the difference between the ideal current and the real-time current. Then, it adjusts the inverter output frequency according to the actual slip, which can quickly respond to speed errors and rapidly adjust the motor speed towards the ideal state. The integral term can eliminate steady-state errors, ensuring that the motor can accurately and stably reach the ideal speed after long-term operation. This control method can effectively cope with speed deviations caused by various factors, achieving relatively precise control of the motor speed. It can also react promptly to common operating conditions such as dynamic changes in motor load and power fluctuations, quickly adjusting the inverter frequency to restore the motor speed to stability as soon as possible. This ensures that the compressor maintains a good operating state without being disturbed by external factors, ensuring that the compressor operates at a suitable speed and improving its performance and stability.

[0010] In a further proposed solution, the steps for calculating the actual slip of the motor based on the current difference include: obtaining the current setting value, calculating a new current setting value based on the current setting value and the current difference, and determining the actual slip of the motor based on the new current setting value.

[0011] Therefore, obtaining the current setpoint and combining it with the current difference to calculate the new current setpoint, and then determining the actual slip of the motor, takes into account the existing settings of the motor in the current control state. This is because the current current setpoint reflects the previous expectations of the control system for the motor's operation. Based on this, combined with the current difference, the actual slip can be calculated more accurately.

[0012] In a further proposed solution, the new current setting value is obtained by the following formula: I n =I o +K i (I * -I); where, I n This is the new current setting, I o This is the current current setting value, K. i It is the integral gain, I * I is the ideal current, and I is the real-time current.

[0013] In a further proposed solution, the steps for adjusting the inverter's output frequency based on the actual slip include: obtaining the inverter's current output frequency and calculating the inverter's new output frequency based on the current output frequency and the actual slip.

[0014] In a further scheme, the new output frequency is obtained by the following formula: f n =f o +K p (ss a ); where f n It's the new output frequency, f o It is the current output frequency, K p s is the proportional gain, s is the expected slip, s a It is an actual deterioration.

[0015] In a further embodiment, the expected slip is obtained by the following formula: Where, n s Let n be the current synchronous speed of the motor, and n be the real-time speed.

[0016] Therefore, motor slip is a key indicator for measuring the difference between the actual operating state and the ideal state of a motor. The magnitude and direction of the actual slip reflect whether the motor speed is too high or too low, and the degree of deviation. By combining it with the current output frequency of the inverter to calculate the new output frequency, targeted and precise adjustments can be achieved.

[0017] In a further proposed solution, the real-time speed of the motor is filtered when the real-time speed is obtained.

[0018] In a further proposed solution, the real-time current of the motor is filtered when it is obtained.

[0019] Therefore, in actual industrial environments, motors are surrounded by numerous electromagnetic interferences and mechanical vibrations, all of which introduce noise into the real-time speed and current signals collected by sensors. Filtering effectively removes this noise interference, restoring speed and current data closer to the true values, thus providing accurate and reliable foundational data for subsequent control calculations.

[0020] To achieve the second objective of the present invention, the present invention provides an air conditioner including a processor and a memory, the memory storing a computer program, which, when executed by the processor, implements the steps of the compressor control method described above.

[0021] To achieve the third objective of the present invention, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a controller, implements the steps of the compressor control method described above. Attached Figure Description

[0022] Figure 1 This is a system schematic diagram of an air conditioner using the compressor control method of the present invention.

[0023] Figure 2 This is a flowchart of an embodiment of the compressor control method of the present invention.

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0025] The compressor control method of the present invention is a computer program applied to an air conditioner for controlling the compressor of the air conditioner.

[0026] In this embodiment, as Figure 1 As shown, the air conditioner includes a main controller 1, an inverter 2, and a compressor motor 3. The main controller 1 controls the frequency output by the inverter 2 to the motor 3, thereby controlling the speed of the motor 3. The motor 3 is also equipped with a motor speed sensor (not shown) and a current sensor (not shown). The motor speed sensor monitors the actual speed of the motor in real time, and the current sensor monitors the input current of the motor in real time. The main controller 1 controls the frequency output by the inverter 2 based on the actual speed and the input current.

[0027] Compressor control method example:

[0028] See Figure 2 In this embodiment, when the compressor control method is working, it first executes step S1 to obtain the real-time speed and ideal speed of the motor, and performs PI control calculation based on the speed difference between the ideal speed and the real-time speed to obtain the ideal current.

[0029] In actual operation, the motor load of the compressor often changes. For example, the compressor load varies under different cooling or heating demands. When the load changes, the motor speed is affected and fluctuates, leading to changes in the speed difference. Therefore, it is necessary to dynamically adjust the ideal current based on this real-time speed difference so that the motor can adapt to load fluctuations and maintain a relatively stable speed. The real-time speed can be obtained through a suitable motor speed sensor installed on the motor. The ideal speed is a target speed value determined in advance based on factors such as the compressor's operating requirements, process settings, or the system's desired operating state. It is usually set by the control system operator according to the actual application scenario. For example, in an air conditioning compressor, based on the optimal performance requirements in cooling or heating modes and combined with the compressor's specifications, an ideal speed value is set that enables the air conditioner to achieve good cooling or heating effects while also considering energy consumption, and this value is stored in the relevant parameter storage area of ​​the controller for subsequent control calculations. The speed difference is obtained by subtracting the ideal speed from the real-time speed. Figure 1 As shown, n* Let n be the set ideal speed, and n be the real-time speed of the motor. The difference between the two speeds is the speed Δn, where Δn = n. * -n is used to obtain the speed difference value, which is then input into the PI controller for proportional and integral calculations to obtain the ideal current.

[0030] In this embodiment, the real-time speed of the motor is filtered when acquiring the real-time speed. By filtering the real-time speed, noise interference can be effectively removed, restoring a speed closer to the true value and improving detection accuracy.

[0031] After obtaining the ideal current, proceed to step S2 to acquire the real-time current of the motor and calculate the current difference between the ideal current and the real-time current. For example... Figure 1 As shown, the ideal current I output by the PI controller * The difference between the real-time current I and the current difference ΔI is obtained, where ΔI = I. * -I.

[0032] Calculating the difference between the ideal current and the real-time current directly reflects the deviation between the actual operating current of the motor and the desired ideal current. This is a crucial basis for further analysis of the motor's operating status and subsequent control operations such as slip calculation. For example, a positive current difference means that the actual motor current is less than the ideal current, which may indicate that the motor's operating status is not meeting expectations, such as insufficient motor drive force due to load changes, requiring appropriate adjustments. Conversely, a negative current difference indicates that the actual motor current is greater than the ideal current, potentially indicating motor overload or other abnormalities. This also necessitates further analysis and corresponding control adjustments to ensure stable and normal motor operation, thereby ensuring the compressor operates efficiently under suitable conditions.

[0033] In this embodiment, the real-time current of the motor is filtered when it is acquired. By filtering the real-time current, noise interference can be effectively removed, restoring current data that is closer to the true value and improving control accuracy.

[0034] After obtaining the current difference, step S3 is executed to calculate the actual slip of the motor based on the current difference. Because current fluctuations are more sensitive than speed fluctuations, even slight changes can be detected. Therefore, calculating the actual slip of the motor based on the current difference allows for more precise speed stability control.

[0035] In this embodiment, the step of calculating the actual slip of the motor based on the current difference includes: obtaining the current setting value, calculating a new current setting value based on the current setting value and the current difference, and determining the actual slip of the motor based on the new current setting value. The new current setting value is obtained by the following formula: In =I o +K i (I * -I); where, I n This is the new current setting, I o This is the current current setting value, K. i It is the preset integral gain, I * I is the ideal current, and I is the real-time current.

[0036] The current setpoint is a reference current value previously set by the control system based on factors such as motor operating requirements, load conditions, and desired operating state. It is typically stored in the controller's parameter storage area. This value represents the current level the control system believes the motor should maintain under a certain stage or specific operating condition; it is an expected setting for the motor's operating current. For example, during the stable operation phase of a compressor, based on the compressor's rated power, set speed, and corresponding load conditions, a suitable current value is pre-set as the current setpoint through relevant theoretical calculations or empirical judgment, thereby guiding the motor to operate in the expected state.

[0037] The current difference reflects the deviation between the actual current and the ideal current. By calculating a new current setting based on the current setting and the current difference, the motor current can be guided back to a reasonable range, making the motor operation state closer to the expectation.

[0038] After obtaining the new current setpoint, the corresponding actual slip of the motor can be obtained. The correspondence between the actual slip and the current setpoint can be preset based on experimental data or by referring to the current-slip characteristic curve in the motor design manual. The new current setpoint is obtained by calculating the difference between the current setpoint and the current value. The actual slip of the motor is then determined based on this new current setpoint. This method fully considers the current setting state of the motor and the actual operating deviations, enabling a more accurate calculation of the actual slip. This provides a reliable basis for further analysis of the motor's operating status, comparison with the expected slip, and corresponding inverter frequency adjustment and other control operations.

[0039] After obtaining the actual slip of the motor, step S4 is executed to adjust the output frequency of the frequency converter according to the actual slip. By monitoring the slip in real time and adjusting the output frequency of the frequency converter according to the actual slip, precise control of the motor speed can be achieved. Regardless of whether the motor slip changes due to load variations, power fluctuations, or other factors, the output frequency of the frequency converter can be adjusted in a timely manner to maintain the motor speed within the desired range, meeting the requirements of compressors and other equipment for motor speed stability and accuracy, and ensuring the efficient operation of the equipment.

[0040] In this embodiment, the step of adjusting the inverter's output frequency based on the actual slip includes: obtaining the inverter's current output frequency, and calculating the inverter's new output frequency based on the current output frequency and the actual slip. The new output frequency is obtained using the following formula: f n =f o +K p (ss a ); where f n It's the new output frequency, f o It is the current output frequency, K p It is the pre-set proportional gain, s is the expected slip, s a This is the actual slip. In this embodiment, the expected slip is obtained by the following formula: Where, n s The current synchronous speed of the motor. f is the set frequency of the inverter, p is the number of pole pairs of the motor, and n is the real-time speed.

[0041] Motor slip is a key indicator that measures the difference between the actual operating state and the ideal state of a motor. The magnitude and direction of slip reflect whether the motor speed is too high or too low, and the degree of deviation. By combining it with the current output frequency of the frequency converter to calculate the new output frequency, and controlling the output frequency of the frequency converter according to the new output frequency, precise adjustment of the frequency converter's output frequency can be achieved, allowing the motor speed to more accurately approach and stabilize at the ideal state.

[0042] As described above, the compressor control method of this invention obtains the ideal current by calculating the difference between the real-time motor speed and the ideal speed using PI control, and calculates the slip based on the difference between the ideal current and the real-time current. Then, it adjusts the inverter output frequency according to the slip, enabling a rapid response to speed errors and quickly adjusting the motor speed towards the ideal state. The integral term eliminates steady-state errors, ensuring that the motor can accurately and stably reach the ideal speed after long-term operation. This control method can effectively cope with speed deviations caused by various factors, achieving relatively precise control of the motor speed. It can also react promptly to common operating conditions such as dynamic changes in motor load and power fluctuations, quickly adjusting the inverter frequency to restore the motor speed to stability as soon as possible. This ensures the compressor maintains a good operating state without being disturbed by external factors, guaranteeing that the compressor operates at a suitable speed and improving its performance and stability.

[0043] Air conditioner example:

[0044] The air conditioner in this embodiment includes a controller, which executes the steps in the compressor control method embodiment described above when executing a computer program.

[0045] For example, a computer program can be divided into one or more modules, one or more of which are stored in memory and executed by a controller to complete the present invention. One or more modules can be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program in an air conditioner.

[0046] An air conditioner may include, but is not limited to, a controller and a memory. Those skilled in the art will understand that an air conditioner may include more or fewer components, or a combination of certain components, or different components; for example, an air conditioner may also include input / output devices, network access devices, buses, etc.

[0047] For example, the controller can be a Central Processing Unit (CPU), or other general-purpose controllers, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose controller can be a microcontroller or any conventional controller. The controller is the control center of the air conditioner, connecting all parts of the air conditioner through various interfaces and lines.

[0048] The memory can be used to store computer programs and / or modules. The controller implements various functions of the air conditioner by running or executing the computer programs and / or modules stored in the memory, and by calling the data stored in the memory. For example, the memory may mainly include a program storage area and a data storage area. The program storage area may store the operating system, at least one application program required for a function (e.g., sound receiving function, sound-to-text function, etc.); the data storage area may store data created based on the use of the mobile phone (e.g., audio data, text data, etc.). In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as hard disk, RAM, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0049] Examples of computer-readable storage media:

[0050] If the modules integrated into the air conditioner in the above embodiments are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above compressor control method embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by the controller, it can implement the steps of the above compressor control method embodiments. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The storage medium can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content contained in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0051] It should be noted that the above are only preferred embodiments of the present invention, but the design concept of the invention is not limited thereto. Any non-substantial modifications made to the present invention using this concept also fall within the protection scope of the present invention.

Claims

1. A compressor control method, characterized in that, include: The real-time speed and ideal speed of the motor are obtained, and the ideal current is obtained by PI control calculation based on the speed difference between the ideal speed and the real-time speed. Obtain the real-time current of the motor and calculate the current difference between the ideal current and the real-time current; The actual slip of the motor is calculated based on the current difference. The steps of calculating the actual slip of the motor based on the current difference include: obtaining the current setting value, calculating a new current setting value based on the current setting value and the current difference, and determining the actual slip of the motor based on the new current setting value. The correspondence between the actual slip of the motor and the current setting value is preset based on experimental data or by querying the current-slip characteristic curve in the motor design manual. Adjust the output frequency of the frequency converter according to the actual slip.

2. The compressor control method according to claim 1, characterized in that: The new current setting value is obtained by the following formula: ； in, This is the new current setting value. This is the current current setting value. It is a pre-set integral gain. It is the ideal current. It is the real-time current.

3. The compressor control method according to claim 1, characterized in that: The steps for adjusting the output frequency of the frequency converter based on the actual slip include: Obtain the current output frequency of the frequency converter, and calculate the new output frequency of the frequency converter based on the current output frequency and the actual slip.

4. The compressor control method according to claim 3, characterized in that: The new output frequency is obtained by the following formula: ； in, It is the new output frequency. It is the current output frequency. It is a preset proportional gain. It is an expectation of deterioration. This refers to the actual slip.

5. The compressor control method according to claim 4, characterized in that: The expected slip is obtained by the following formula: ； in, The current synchronous speed of the motor. The real-time rotational speed is denoted as .

6. The compressor control method according to any one of claims 1 to 5, characterized in that: When obtaining the real-time speed of the motor, the real-time speed is filtered.

7. The compressor control method according to any one of claims 1 to 5, characterized in that: When acquiring the real-time current of the motor, the real-time current is filtered.

8. An air conditioner, comprising a processor and a memory, characterized in that: The memory stores a computer program that, when executed by the processor, implements the steps of the compressor control method as described in any one of claims 1 to 7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the controller, it implements the steps of the compressor control method as described in any one of claims 1 to 7.

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