Compressor control method, control device and variable frequency air conditioner

Abstract

This invention discloses a compressor control method, control device, and inverter air conditioner. The control method includes: acquiring the current three-phase current of the compressor; acquiring a current adjustment bus voltage command based on the current three-phase current; when the compressor is in a field weakening control mode, limiting the current adjustment bus voltage command using a current limiting value to obtain a current actual bus voltage command; performing power factor correction control based on the current actual bus voltage command; the current limiting value includes a current maximum limiting value, which is determined based on the compressor's current speed; when the compressor is in a non-field weakening control mode, limiting the current adjustment bus voltage command using a fixed limiting value to obtain a current actual bus voltage command; and performing power factor correction control based on the current actual bus voltage command. Using this invention, the performance of the compressor can be improved in different control processes.

Description

Technical Field

[0001] This invention belongs to the field of compressor control technology, specifically, it relates to compressor control methods, control devices, and variable frequency air conditioners. Background Technology

[0002] The compressor control of a variable frequency air conditioner typically includes power factor correction control and field weakening control. Power factor correction control adjusts and matches the input and output power of the air conditioning control system to achieve the optimal power factor, thereby improving system energy efficiency, reducing energy consumption, and enhancing system reliability and stability. Field weakening control reduces the compressor's main magnetic flux, enabling it to operate at higher speeds while maintaining a certain output power. Field weakening control is usually achieved by adjusting the stator current, particularly by increasing the demagnetizing current component of the stator's d-axis to maintain voltage balance during high-speed operation.

[0003] In related technologies, power factor correction typically employs a constant bus command voltage as the target value for power factor correction control. While using a constant bus command voltage is simple, it can easily lead to high energy consumption and low efficiency, especially under light loads and load variations. This can prevent the system from operating at its optimal state, resulting in unnecessary energy loss and decreased system efficiency.

[0004] Therefore, how to reduce compressor energy consumption and improve compressor efficiency while ensuring the stability of the compressor system under weak magnetic control, and how to optimize the performance of the compressor in different control processes, are technical problems that need to be solved. Summary of the Invention

[0005] One of the objectives of this invention is to provide a compressor control method and control device to improve the performance of the compressor in different control processes.

[0006] To achieve the above-mentioned objectives, the compressor control method provided by this invention adopts the following technical solution:

[0007] A compressor control method, comprising:

[0008] Obtain the current three-phase current of the compressor;

[0009] The current d-axis voltage and the current q-axis voltage are obtained based on the current three-phase current.

[0010] The current d-axis voltage and the current q-axis voltage are processed to obtain the processed voltage signal;

[0011] The processed voltage signal is multiplied by the reciprocal of the adjustment coefficient, and the product is determined as the current bus voltage adjustment command.

[0012] When the compressor is in field weakening control mode, the following first control procedure is executed:

[0013] The current bus voltage adjustment command is subjected to a limiting value to obtain a bus voltage command with the current limiting value, which is then determined as the current actual bus voltage command.

[0014] Power factor correction control is performed based on the current actual bus voltage command;

[0015] The current limit value includes the current maximum limit value, which is determined based on the current speed of the compressor, and the current maximum limit value and the current speed satisfy a positive correlation.

[0016] When the compressor is in non-field weakening control mode, the following second control process is executed:

[0017] The current bus voltage adjustment command is subjected to a fixed limiting value for limiting processing to obtain the bus voltage command after limiting processing, which is then determined as the current actual bus voltage command.

[0018] Power factor correction control is performed based on the current actual bus voltage command;

[0019] The fixed limiting value includes a fixed maximum limiting value.

[0020] In some embodiments of this application, the adjustment coefficient is determined using the following process:

[0021] Obtain the harmonic components of the current phase current of the compressor, and obtain the current fundamental component and the current nth harmonic component based on the harmonic components of the current phase current; n is the harmonic number and is a natural number greater than 1.

[0022] Calculate the sum of multiple specified harmonic components in the current nth harmonic component, and use it as the current harmonic component sum;

[0023] Compare the current harmonic component with the current fundamental component;

[0024] If the ratio of the sum of the current harmonic components to the current fundamental component is less than a set ratio, the adjustment coefficient is taken as a reference value; the set ratio is a positive number less than 1.

[0025] If the ratio of the sum of the current harmonic components to the current fundamental component is greater than or equal to the set ratio, the adjustment coefficient is taken as a correction value; the correction value is determined according to the reference value, and the correction value is less than the reference value.

[0026] In some embodiments of this application, calculating the sum of multiple specified harmonic components in the current nth harmonic component as the current harmonic component sum specifically includes:

[0027] Arrange the current nth harmonic components in ascending order of harmonic order;

[0028] Take the specified number of odd-order harmonic components that are ranked first as the specified harmonic components, calculate the sum of all the specified harmonic components, and take it as the sum of the current harmonic components.

[0029] In some embodiments of this application, the current d-axis voltage and the current q-axis voltage are processed to obtain a processed voltage signal, specifically including:

[0030] Calculate the square root of the sum of the square of the current d-axis voltage and the square of the current q-axis voltage, and determine the result as the processed voltage signal.

[0031] In some embodiments of this application, the current d-axis voltage and the current q-axis voltage are processed to obtain a processed voltage signal, specifically including:

[0032] Calculate the square root of the sum of the square of the current d-axis voltage and the square of the current q-axis voltage, and determine the result as the initial voltage signal;

[0033] The initial voltage signal is processed to obtain the processed voltage signal.

[0034] In some embodiments of this application, the initial voltage signal is processed to obtain the processed voltage signal, specifically including:

[0035] Acquire multiple initial voltage signals within the currently set time period;

[0036] The average value of the multiple initial voltage signals within the current set time period is determined as the processed voltage signal;

[0037] Alternatively, the maximum value among the multiple initial voltage signals within the currently set time period can be determined as the processed voltage signal;

[0038] Alternatively, the larger of the average value of the multiple initial voltage signals within the current set time period and the average value of the multiple initial voltage signals within the previous set time period can be determined as the processed voltage signal.

[0039] Alternatively, the larger of the maximum value among the multiple initial voltage signals within the current set time period and the maximum value among the multiple initial voltage signals within the previous set time period can be determined as the processed voltage signal.

[0040] In some embodiments of this application, the initial voltage signal is processed to obtain the processed voltage signal, specifically including:

[0041] Acquire multiple initial voltage signals within the current electrical cycle; the electrical cycle is the period during which the compressor's stator current changes from 0° to 360°.

[0042] The average value of the multiple initial voltage signals within the current electrical cycle is determined as the processed voltage signal;

[0043] Alternatively, the maximum value among the multiple initial voltage signals within the current electrical cycle can be determined as the processed voltage signal;

[0044] Alternatively, the larger of the average value of the multiple initial voltage signals in the current electrical cycle and the average value of the multiple initial voltage signals in the previous electrical cycle can be determined as the processed voltage signal.

[0045] Alternatively, the larger of the maximum value among the multiple initial voltage signals in the current electrical cycle and the maximum value among the multiple initial voltage signals in the previous electrical cycle can be determined as the processed voltage signal.

[0046] In some embodiments of this application, the initial voltage signal is processed to obtain the processed voltage signal, specifically including:

[0047] Acquire multiple initial voltage signals within the current mechanical cycle; the mechanical cycle is the cycle in which the compressor rotor rotates from 0° to 360°.

[0048] The average value of the multiple initial voltage signals within the current mechanical cycle is determined as the processed voltage signal;

[0049] Alternatively, the maximum value among the multiple initial voltage signals within the current mechanical cycle can be determined as the processed voltage signal;

[0050] Alternatively, the larger of the average value of the multiple initial voltage signals in the current mechanical cycle and the average value of the multiple initial voltage signals in the previous mechanical cycle can be determined as the processed voltage signal.

[0051] Alternatively, the larger of the maximum value among the multiple initial voltage signals in the current mechanical cycle and the maximum value among the multiple initial voltage signals in the previous mechanical cycle can be determined as the processed voltage signal.

[0052] To achieve the aforementioned objectives, the compressor control device provided by this invention employs the following technical solution:

[0053] A compressor control device, comprising:

[0054] The three-phase current acquisition unit is used to acquire the current three-phase current of the compressor;

[0055] The bus voltage adjustment command acquisition unit is used to acquire the current d-axis voltage and the current q-axis voltage based on the current three-phase current, process the current d-axis voltage and the current q-axis voltage to obtain the processed voltage signal, and multiply the processed voltage signal by the reciprocal of the adjustment coefficient, and the product is determined as the current bus voltage adjustment command.

[0056] The control mode determination unit is used to determine whether the compressor is in the field weakening control mode;

[0057] The first control unit is configured to execute the following first control process when the compressor is in the field weakening control mode: limiting the current bus voltage adjustment command using the current limiting value to obtain the limited bus voltage command, which is then determined as the current actual bus voltage command; performing power factor correction control based on the current actual bus voltage command; the current limiting value includes the current maximum limiting value, which is determined based on the current speed of the compressor, and the current maximum limiting value and the current speed satisfy a positive correlation.

[0058] The second control unit is used to execute the following two control processes when the compressor is in non-field weakening control mode: applying a fixed limiting value to the current adjustment bus voltage command to obtain the limited bus voltage command, and determining it as the current actual bus voltage command; performing power factor correction control according to the current actual bus voltage command; the fixed limiting value includes a fixed maximum limiting value.

[0059] The present invention also provides a variable frequency air conditioner, including a compressor, and the variable frequency air conditioner further includes the compressor control device described above.

[0060] Compared with the prior art, the advantages and positive effects of the present invention are:

[0061] The compressor control method and control device provided by this invention, in the non-field weakening control mode, the actual bus voltage command is not a fixed value, but is adjusted in real time according to the changes in compressor load. Power factor correction control is then performed based on the adjusted bus voltage command, enabling the system bus voltage to dynamically adjust with load changes. This achieves a higher power factor while reducing system power loss and allows the compressor system to quickly reach and maintain a stable operating state, improving the compressor system's efficiency. In the field weakening control mode, the bus voltage command is still adjusted in real time according to load changes. Simultaneously, a maximum limit value is determined based on the compressor speed. The adjusted bus voltage command is limited according to this maximum limit value to obtain the actual bus voltage command, ensuring that the actual bus voltage command also changes with the compressor speed. At higher compressor speeds, the bus voltage command is also increased, ensuring that the power factor correction circuit outputs a large bus voltage even at higher compressor speeds under field weakening control. This avoids insufficient bus voltage that could cause power factor correction control and compressor control to malfunction or even shut down the compressor, improving the stability of the field weakening control mode. Therefore, by using this invention to control the compressor, the energy consumption of the compressor is reduced and the working efficiency of the compressor is improved, while ensuring the stability of the compressor system during weak magnetic control, and optimizing the performance of the compressor in different control processes.

[0062] Other features and advantages of the present invention will become clearer after reading the detailed embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0063] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0064] Figure 1 A flowchart of the first embodiment of the compressor control method provided by the present invention;

[0065] Figure 2 A flowchart of the second embodiment of the compressor control method provided by the present invention;

[0066] Figure 3 This is a structural block diagram of one embodiment of the compressor control device provided by the present invention. Detailed Implementation

[0067] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0068] It should be noted that the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they can be implemented by those skilled in the art. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0069] Figure 1 The flowchart shown is a first embodiment of the compressor control method provided by the present invention, wherein the compressor is the compressor of an inverter air conditioner.

[0070] like Figure 1 As shown, this embodiment employs the following process to perform compressor control.

[0071] S101: Get the current three-phase current of the compressor.

[0072] The current three-phase current of the compressor refers to the three-phase current of the compressor obtained by real-time sampling according to a set sampling frequency. The method for obtaining the three-phase current adopts existing technology, and this embodiment does not limit the acquisition method.

[0073] S102: Obtain the current d-axis voltage and the current q-axis voltage based on the current three-phase current.

[0074] The process is implemented using existing technology, and this embodiment does not limit it.

[0075] In some embodiments, the current three-phase current is first subjected to Clark transformation by a conversion unit to obtain the compressor current I in the α-axis direction of the two-phase stationary coordinate system. α and the current I in the β-axis direction β Then, combining the estimated compressor rotor angle, the current I in the α-axis direction is controlled by the conversion unit. α and the current I in the β-axis direction β Perform a Park transformation to obtain the current actual d-axis current I in a two-phase rotating coordinate system. d and the current q-axis actual current I q Then, combined with the given d-axis current I... d * q-axis given current I q * For the current actual d-axis current I d Current q-axis actual current I q The current d-axis voltage V is obtained by processing with a current regulator. d and the current q-axis voltage V q The method for obtaining the compressor rotor angle estimate can be achieved using existing technology. The d-axis given current I... d * and q-axis given current I q* The value is known.

[0076] S103: Process the current d-axis voltage and the current q-axis voltage to obtain the processed voltage signal.

[0077] S104: Multiply the processed voltage signal by the reciprocal of the adjustment coefficient, and the product is determined as the current bus voltage adjustment command.

[0078] The adjustment coefficient can be a set value or an obtainable value, and this embodiment does not limit the way its value is determined.

[0079] S105: Determine whether the compressor is in weak field control mode, so as to execute different control processes according to the determination result.

[0080] Determining whether the compressor is in a weak magnetic control mode can be achieved using existing related technologies, and this embodiment does not limit the specific determination method.

[0081] In some embodiments, the compressor speed can be used as the basis for judgment. If the compressor speed is greater than the base speed, it is determined that the compressor is in the weak magnetic control mode.

[0082] S106: When it is determined in step S105 that the compressor is in the weak magnetic control mode, the first control process is executed.

[0083] The first control process specifically includes: applying the current limiting value to the current adjustment bus voltage command obtained in step S104 to perform limiting processing, obtaining the limited bus voltage command, and determining it as the current actual bus voltage command; then, performing power factor correction control based on the current actual bus voltage command.

[0084] The current limit value is a limit value obtained in real time according to the frequency of the current bus voltage adjustment command. The current limit value can be a value read in real time from stored data, or a value calculated or queried in real time based on parameters.

[0085] The current limiting value includes the current maximum limiting value. When the current bus voltage adjustment command is limited using the current limiting value, if the current bus voltage adjustment command is greater than the current maximum limiting value, the bus voltage command greater than the current maximum limiting value will be discarded, and the current maximum limiting value will be output as the maximum value of the voltage command. That is, the maximum value of the current actual bus voltage command output after limiting is the current maximum limiting value.

[0086] Limiting the system using the current limit value can prevent system instability caused by operating outside the limit. However, it may also lead to issues such as not meeting load requirements. Therefore, in this embodiment, the current maximum limit value is determined based on the compressor's current speed, and there is a positive correlation between the current maximum limit value and the current speed. That is, the higher the current speed, the higher the corresponding current maximum limit value; the lower the current speed, the lower the corresponding current maximum limit value. The current speed is the compressor speed obtained in real time by following the frequency of the current bus voltage adjustment command.

[0087] In some embodiments, the positive correlation between the current maximum amplitude limit and the current rotational speed can be pre-stored in the form of a correspondence table, and the current maximum amplitude limit can be obtained by querying the correspondence table after obtaining the current rotational speed.

[0088] In some other embodiments, the positive correlation between the current maximum amplitude limit and the current rotational speed is stored using a pre-stored calculation formula. After obtaining the current rotational speed, the calculation formula is used to calculate the current maximum amplitude limit.

[0089] Under field weakening control, the higher the compressor speed, the higher the demand for the bus voltage output by the power factor correction circuit. By determining the current maximum limit based on the current speed, the current maximum limit is also larger when the current speed is higher, so as to increase the current actual bus voltage command as much as possible, thereby increasing the bus voltage output by the power factor correction circuit, so as to achieve the goal of obtaining a larger bus voltage in the field weakening control mode.

[0090] After receiving the current actual bus voltage command, the power factor correction circuit performs power factor correction on the input AC power based on the current actual bus voltage command and the compressor feedback voltage to obtain stable DC power.

[0091] S107: In step S105, if the compressor is determined to be in non-weakening control mode, the second control process is executed.

[0092] The second control process includes: applying a fixed limiting value to the current adjustment bus voltage command obtained in step S104 to obtain the bus voltage command after limiting, and determining it as the current actual bus voltage command; then, performing power factor correction control based on the current actual bus voltage command.

[0093] The fixed limiting value includes a fixed maximum limiting value, which is a known value. When using this fixed limiting value to limit the current bus voltage adjustment command, if the current bus voltage adjustment command exceeds the fixed maximum limiting value, the command exceeding the fixed maximum limiting value will be discarded, and the fixed maximum limiting value will be output as the maximum value of the voltage command. In other words, the maximum value of the current actual bus voltage command output after limiting is the fixed maximum limiting value. Using the fixed maximum limiting value for limiting can prevent system instability caused by the system operating outside the limiting value.

[0094] The specific value of the fixed maximum limit can be set according to actual needs and system structure. Under non-weakening field control, the compressor speed is generally low, and the demand for bus voltage is also low, so a smaller fixed value can be selected for the fixed maximum limit.

[0095] In the second control process, after obtaining the current actual bus voltage command, the power factor correction circuit performs power factor correction on the input AC power according to the current actual bus voltage command and the feedback voltage of the compressor to obtain stable DC power.

[0096] In this embodiment, the d-axis and q-axis voltages are obtained based on the compressor's three-phase current. A processed voltage signal is then obtained from these voltages, and the current adjustment bus voltage command is determined based on the processed voltage signal and the adjustment coefficient. In non-field weakening control mode, the current adjustment bus voltage command is limited by a fixed limiting value, and power factor correction control is performed using the limited actual bus voltage command. In field weakening control mode, a maximum limiting value is determined based on the compressor speed. The current adjustment bus voltage command is limited based on this maximum limiting value to obtain the actual bus voltage command, and power factor correction control is performed based on the actual bus voltage command.

[0097] Therefore, using the method described in the above embodiments, in the non-field weakening control mode, the actual bus voltage command is not a fixed value, but is adjusted in real time according to changes in the compressor load. Power factor correction control is then performed based on the adjusted bus voltage command, enabling the system bus voltage to dynamically adjust with load changes. This achieves a higher power factor while reducing system power loss and allows the compressor system to quickly reach and maintain a stable operating state, improving the compressor system's efficiency. In the field weakening control mode, the bus voltage command is still adjusted in real time according to load changes and also changes with compressor speed. At higher compressor speeds, the bus voltage command is increased, ensuring that the power factor correction circuit outputs a large bus voltage even at higher compressor speeds under field weakening control. This prevents insufficient bus voltage from causing power factor correction control and compressor control malfunctions, or even compressor shutdown, thus improving the stability of the field weakening control mode. Therefore, while reducing compressor energy consumption and improving compressor efficiency, the stability of the compressor system under field weakening control is guaranteed, optimizing compressor performance in different control processes.

[0098] In some other embodiments, the adjustment factor used to determine the current bus voltage adjustment command is a dynamically variable value, and the value of the adjustment factor is determined using the following process:

[0099] First, the harmonic components of the current phase current of the compressor are obtained. Based on the harmonic components of the current phase current, the current fundamental component and the current nth harmonic component are obtained. Here, n is the harmonic order, and n is a natural number greater than 1. The current of any phase of the compressor can be selected as the current phase current. The method of performing harmonic analysis on the current to obtain the harmonic components, and then obtaining the fundamental component and the nth harmonic component (higher harmonic components) from the harmonic components, can be implemented using existing technologies, and this embodiment does not limit this approach.

[0100] Then, the sum of multiple specified harmonic components in the current nth harmonic component is calculated as the current harmonic component sum.

[0101] The specified subharmonic components can be selected according to the actual situation.

[0102] In some embodiments, taking advantage of the characteristic that harmonic components gradually decrease with increasing harmonic order, to improve processing speed, the current nth harmonic components are arranged in ascending order of harmonic order, and a specified number of the top-ranked harmonic components are selected as the specified harmonic components. The specified number can be selected according to the actual situation. For example, in some embodiments, the specified number is 5. Then, after arranging the current nth harmonic components in ascending order of harmonic order, the top 5 harmonic components, that is, the 2nd, 3rd, 4th, 5th, and 6th harmonic components, are selected as the specified harmonic components.

[0103] In other embodiments, the specified harmonic components are determined by the following process: The current n-th harmonic components are arranged in ascending order of harmonic order, and a specified number of odd-order harmonic components at the top of the order are selected as the specified harmonic components. Odd-order harmonics have a greater impact on compressors and air conditioning systems, potentially causing additional losses, vibrations, and noise. Since the number of harmonic components gradually decreases with increasing order, selecting the top-order odd-order harmonic components for summation calculations balances processing speed and accuracy. The specified number can be selected based on actual conditions. For example, in some embodiments, the specified number is 5. Then, after arranging the current n-th harmonic components in ascending order of harmonic order, the top 5 odd-order harmonic components—that is, the 3rd, 5th, 7th, 9th, and 11th harmonic components—are selected as the specified harmonic components.

[0104] After obtaining the sum of the current harmonic components, the sum of the current harmonic components is compared with the already obtained current fundamental component, and the value of the adjustment coefficient is determined based on the comparison result.

[0105] Specifically, if the ratio of the sum of the current harmonic components to the current fundamental component is less than a set ratio, the adjustment coefficient is set to a reference value. The reference value is a known value, and its specific value can be set according to actual needs. Under this value, using the bus voltage command determined by the reference value for compressor control can improve power utilization and the compressor's high-speed operation capability. The set ratio is a positive number less than 1, and its value is known and can be specifically selected according to actual needs; this embodiment does not limit the specific value. In some embodiments, the set ratio ranges from [0.10, 0.25]. When the ratio of the sum of the current harmonic components to the current fundamental component is less than the set ratio, that is, when the sum of the current harmonic components is less than the product of the current fundamental component and the set ratio, it indicates that the harmonic components are within an acceptable range. The adjustment coefficient is set to a known reference value to obtain higher power utilization and the compressor's high-speed operation capability, thereby achieving the goal of reducing energy consumption and improving performance.

[0106] If the ratio of the sum of the current harmonic components to the current fundamental component is greater than or equal to a set ratio, the adjustment coefficient is set to a correction value. The correction value is determined based on a reference value and must be less than the reference value. If the ratio of the sum of the current harmonic components to the current fundamental component is not less than a set ratio (i.e., the sum of the current harmonic components is not less than the product of the current fundamental component and the set ratio), it indicates a large harmonic component and a high degree of phase current distortion. In this case, a smaller correction value is used to obtain a larger bus voltage command value. Compressor control is then performed based on this larger bus voltage command value to reduce the harmonic component of the compressor phase current and improve system stability.

[0107] In the above embodiments, the adjustment coefficient of the bus voltage command is adjusted in real time according to the harmonic components of the phase current fed back by the compressor. While ensuring that the compressor has the ability to operate at high speed and instantaneous overload capacity, the distortion of the compressor phase current is reduced, so as to achieve the purpose of taking into account the compressor performance, efficiency, service life and stability of the variable frequency air conditioning system to which the compressor is used.

[0108] Figure 2 The flowchart shown is a second embodiment of the compressor control method provided by the present invention. Specifically, it is a flowchart of an embodiment for determining the current adjustment bus voltage command.

[0109] In this embodiment, the current bus voltage adjustment command is dynamically acquired based on the load size. Then, depending on whether the field weakening control mode is in effect, different limiting processing methods are adopted to determine the actual bus voltage command used for control based on the current bus voltage adjustment command. Control is then performed according to the determined current bus voltage command. Specifically, this embodiment acquires the current bus voltage adjustment command using the following process.

[0110] S201: Get the current three-phase current of the compressor.

[0111] S202: Obtain the current d-axis voltage and the current q-axis voltage based on the current three-phase current.

[0112] For the specific implementation of steps S201 and S202 above, please refer to [link / reference]. Figure 1 The corresponding description of the embodiments.

[0113] S203: Calculate the square root of the sum of the squares of the current d-axis voltage and the squares of the current q-axis voltage, and determine the result as the initial voltage signal.

[0114] The initial voltage signal is denoted as V0, and the current d-axis voltage is V. d The current q-axis voltage is V. q Then we have:

[0115]

[0116] S204: Process the initial voltage signal to obtain the processed voltage signal.

[0117] S205: Multiply the processed voltage signal by the reciprocal of the adjustment coefficient, and the product is determined as the current bus voltage adjustment command.

[0118] The initial voltage signal is processed in step S204 above to obtain the processed voltage signal, which can be achieved in a variety of ways.

[0119] In some embodiments, the initial voltage signal is processed to obtain a processed voltage signal, specifically including:

[0120] Acquire multiple initial voltage signals within the currently set time period. The length of the set time period can be set according to actual needs.

[0121] Then, the average value of multiple initial voltage signals within the current set time period is determined as the processed voltage signal.

[0122] By using the average value of the initial voltage signal within a set time period as the processed voltage signal, the influence of all initial voltage signals can be taken into account, ensuring the accuracy of the determined bus voltage command as much as possible, thereby improving the accuracy of compressor control. Moreover, by acquiring a processed voltage signal only once every set time period and adjusting the bus voltage command once, the instability of system operation caused by frequent adjustments to the bus voltage command can be avoided.

[0123] In some other embodiments, the initial voltage signal is processed to obtain a processed voltage signal, specifically including:

[0124] Acquire multiple initial voltage signals within the currently set time period. The length of the set time period can be set according to actual needs.

[0125] The maximum value among multiple initial voltage signals within the currently set time period is determined as the processed voltage signal.

[0126] By using the maximum value of multiple initial voltage signals within a set time period as the processed voltage signal, the larger voltage signal has a greater impact on the result, which can ensure the accuracy of the determined bus voltage command as much as possible, thereby improving the accuracy of compressor control. Moreover, by acquiring a processed voltage signal only once every set time period and adjusting the bus voltage command once, the instability of system operation caused by frequent adjustments to the bus voltage command can be avoided.

[0127] In some other embodiments, the initial voltage signal is processed to obtain a processed voltage signal, specifically including:

[0128] Acquire multiple initial voltage signals within the currently set time period. The length of the set time period can be set according to actual needs.

[0129] The larger of the average value of multiple initial voltage signals within the current set time period and the average value of multiple initial voltage signals within the previous set time period is determined as the processed voltage signal; or, the larger of the maximum value among multiple initial voltage signals within the current set time period and the maximum value among multiple initial voltage signals within the previous set time period is determined as the processed voltage signal.

[0130] By selecting the maximum or average value of multiple initial voltage signals within two adjacent set time periods as the processed voltage signal, the number of bus voltage command adjustments is reduced, and the instability of system operation caused by frequent adjustments is avoided. At the same time, the accuracy of the processed voltage signal is improved as much as possible, thereby ensuring the accuracy of the determined bus voltage command and improving the accuracy of compressor control.

[0131] In other embodiments, the initial voltage signal is processed to obtain a processed voltage signal, specifically including:

[0132] Acquire multiple initial voltage signals within the current electrical cycle. The electrical cycle is the period during which the compressor's stator current changes from 0° to 360°, and it is also the time required for the compressor to output a complete electrical signal.

[0133] Then, the average value of multiple initial voltage signals within the current electrical cycle is determined as the processed voltage signal.

[0134] By using the average value of the initial voltage signal within one electrical cycle as the processed voltage signal, the influence of all initial voltage signals within a complete electrical signal cycle can be considered, ensuring the accuracy of the determined bus voltage command as much as possible, thereby improving the accuracy of compressor control. Moreover, by acquiring a processed voltage signal only once every electrical cycle and adjusting the bus voltage command once, the instability of system operation caused by frequent adjustments to the bus voltage command can be avoided.

[0135] In some other embodiments, the initial voltage signal is processed to obtain a processed voltage signal, specifically including:

[0136] Acquire multiple initial voltage signals within the current electrical cycle.

[0137] The maximum value among multiple initial voltage signals within the current electrical cycle is determined as the processed voltage signal.

[0138] By using the maximum value of multiple initial voltage signals within one electrical cycle as the processed voltage signal, the larger voltage signal has a greater impact on the result, which can ensure the accuracy of the determined bus voltage command as much as possible, thereby improving the accuracy of compressor control. Moreover, by acquiring a processed voltage signal only once every electrical cycle and adjusting the bus voltage command once, the instability of system operation caused by frequent adjustments to the bus voltage command can be avoided.

[0139] In some other embodiments, the initial voltage signal is processed to obtain a processed voltage signal, specifically including:

[0140] Acquire multiple initial voltage signals within the current electrical cycle.

[0141] The larger of the average value of multiple initial voltage signals in the current electrical cycle and the average value of multiple initial voltage signals in the previous electrical cycle is determined as the processed voltage signal; or, the larger of the maximum value among multiple initial voltage signals in the current electrical cycle and the maximum value among multiple initial voltage signals in the previous electrical cycle is determined as the processed voltage signal.

[0142] By selecting the maximum or average value of multiple initial voltage signals within two adjacent electrical cycles as the processed voltage signal, the number of bus voltage command adjustments is reduced, and the instability of system operation caused by frequent adjustments is avoided. At the same time, the accuracy of the processed voltage signal is improved as much as possible, thereby ensuring the accuracy of the determined bus voltage command and improving the accuracy of compressor control.

[0143] In other embodiments, the initial voltage signal is processed to obtain a processed voltage signal, specifically including:

[0144] Acquire multiple initial voltage signals within the current mechanical cycle. The mechanical cycle is the period during which the compressor rotor rotates from 0° to 360°. A mechanical cycle typically comprises multiple electrical cycles, and the mechanical cycle is the product of the number of pole pairs and the number of electrical cycles.

[0145] Then, the average value of multiple initial voltage signals within the current mechanical cycle is determined as the processed voltage signal.

[0146] By using the average value of the initial voltage signal within a mechanical cycle as the processed voltage signal, the influence of all initial voltage signals within a complete mechanical cycle can be considered, ensuring the accuracy of the determined bus voltage command as much as possible, thereby improving the accuracy of compressor control. Moreover, by acquiring a processed voltage signal only once every mechanical cycle and adjusting the bus voltage command once, the instability of system operation caused by frequent adjustments to the bus voltage command can be avoided.

[0147] In some other embodiments, the initial voltage signal is processed to obtain a processed voltage signal, specifically including:

[0148] Acquire multiple initial voltage signals within the current mechanical cycle.

[0149] The maximum value among multiple initial voltage signals within the current mechanical cycle is determined as the processed voltage signal.

[0150] By using the maximum value of multiple initial voltage signals within a mechanical cycle as the processed voltage signal, the larger voltage signal has a greater impact on the result, which can ensure the accuracy of the determined bus voltage command as much as possible, thereby improving the accuracy of compressor control. Moreover, by acquiring a processed voltage signal only once every mechanical cycle and adjusting the bus voltage command once, the instability of system operation caused by frequent adjustments to the bus voltage command can be avoided.

[0151] In some other embodiments, the initial voltage signal is processed to obtain a processed voltage signal, specifically including:

[0152] Acquire multiple initial voltage signals within the current mechanical cycle.

[0153] The larger of the average value of multiple initial voltage signals in the current mechanical cycle and the average value of multiple initial voltage signals in the previous mechanical cycle is determined as the processed voltage signal; or, the larger of the maximum value among multiple initial voltage signals in the current mechanical cycle and the maximum value among multiple initial voltage signals in the previous mechanical cycle is determined as the processed voltage signal.

[0154] By selecting the maximum or average value of multiple initial voltage signals within two adjacent mechanical cycles as the processed voltage signal, the number of bus voltage command adjustments is reduced, and the instability of system operation caused by frequent adjustments is avoided. At the same time, the accuracy of the processed voltage signal is improved as much as possible, thereby ensuring the accuracy of the determined bus voltage command and improving the accuracy of compressor control.

[0155] In some other embodiments, the initial voltage signal determined by the square root of the sum of the square of the current d-axis voltage and the square of the current q-axis voltage is directly used as the processed voltage signal to determine the bus voltage command.

[0156] Figure 3 A structural block diagram of an embodiment of the compressor control device provided by the present invention is shown. The control device of this embodiment includes structural units, the relationships between structural units, and the function of each structural unit, which are described in detail below.

[0157] like Figure 3 As shown, the compressor control device includes:

[0158] The three-phase current acquisition unit 31 is used to acquire the current three-phase current of the compressor.

[0159] The bus voltage adjustment command acquisition unit 32 is used to acquire the current d-axis voltage and the current q-axis voltage based on the current three-phase current acquired by the three-phase current acquisition unit 31, process the current d-axis voltage and the current q-axis voltage to obtain the processed voltage signal, and multiply the processed voltage signal by the reciprocal of the adjustment coefficient, and the product is determined as the current bus voltage adjustment command.

[0160] The control mode determination unit 33 is used to determine whether the compressor is in the field weakening control mode.

[0161] The first control unit 34 is used to execute the following first control process when the control mode judgment unit 33 determines that the compressor is in the field weakening control mode: the current adjustment bus voltage command obtained by the adjustment bus voltage command acquisition unit 32 is subjected to the current limiting value for limiting processing to obtain the bus voltage command after limiting processing, and determined as the current actual bus voltage command; power factor correction control is performed according to the current actual bus voltage command; the current limiting value includes the current maximum limiting value, the current maximum limiting value is determined according to the current speed of the compressor, and the current maximum limiting value and the current speed satisfy a positive correlation.

[0162] The second control unit 35 is used to execute the following second control process when the control mode judgment unit 33 determines that the compressor is in a non-field weakening control mode: the current adjustment bus voltage command obtained by the adjustment bus voltage command acquisition unit 32 is subjected to a fixed limiting value to obtain the bus voltage command after limiting, and determined as the current actual bus voltage command; power factor correction control is performed according to the current actual bus voltage command; the fixed limiting value includes a fixed maximum limiting value.

[0163] The control device of the above structure runs the corresponding software program, performs the corresponding functions, and follows the instructions. Figure 1 The compressor control method embodiments and other embodiments perform compressor control to achieve the desired effect. Figure 1 The corresponding technical effects of the embodiments and other embodiments.

[0164] The compressor control device described in the above embodiment is applied to the control of the compressor in a variable frequency air conditioner, which can improve the performance of the variable frequency air conditioner in different control processes.

[0165] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions claimed by the present invention.

Claims

1. A compressor control method, characterized in that, The control method includes: Obtain the current three-phase current of the compressor; The current d-axis voltage and the current q-axis voltage are obtained based on the current three-phase current. The current d-axis voltage and the current q-axis voltage are processed to obtain the processed voltage signal; The processed voltage signal is multiplied by the reciprocal of the adjustment coefficient, and the product is determined as the current bus voltage adjustment command. When the compressor is in field weakening control mode, the following first control procedure is executed: The current bus voltage adjustment command is subjected to a limiting value to obtain a bus voltage command with the current limiting value, which is then determined as the current actual bus voltage command. Power factor correction control is performed based on the current actual bus voltage command; The current limit value includes the current maximum limit value, which is determined based on the current speed of the compressor, and the current maximum limit value and the current speed satisfy a positive correlation. When the compressor is in non-field weakening control mode, the following two control processes are executed: The current bus voltage adjustment command is subjected to a fixed limiting value for limiting processing to obtain the bus voltage command after limiting processing, which is then determined as the current actual bus voltage command. Power factor correction control is performed based on the current actual bus voltage command; The fixed limiting value includes a fixed maximum limiting value.

2. The compressor control method according to claim 1, characterized in that, The adjustment factor is determined using the following process: Obtain the harmonic components of the current phase current of the compressor, and obtain the current fundamental component and the current nth harmonic component based on the harmonic components of the current phase current; n is the harmonic number and is a natural number greater than 1. Calculate the sum of multiple specified harmonic components in the current nth harmonic component, and use it as the current harmonic component sum; Compare the current harmonic component with the current fundamental component; If the ratio of the sum of the current harmonic components to the current fundamental component is less than a set ratio, the adjustment coefficient is taken as a reference value; the set ratio is a positive number less than 1. If the ratio of the sum of the current harmonic components to the current fundamental component is greater than or equal to the set ratio, the adjustment coefficient is taken as a correction value; the correction value is determined according to the reference value, and the correction value is less than the reference value.

3. The compressor control method according to claim 2, characterized in that, Calculating the sum of multiple specified harmonic components in the current nth harmonic component as the current harmonic component sum, specifically includes: Arrange the current nth harmonic components in ascending order of harmonic order; Take the specified number of odd-order harmonic components that are ranked first as the specified harmonic components, calculate the sum of all the specified harmonic components, and take it as the sum of the current harmonic components.

4. The compressor control method according to any one of claims 1 to 3, characterized in that, The current d-axis voltage and the current q-axis voltage are processed to obtain a processed voltage signal, specifically including: Calculate the square root of the sum of the square of the current d-axis voltage and the square of the current q-axis voltage, and determine the result as the processed voltage signal.

5. The compressor control method according to any one of claims 1 to 3, characterized in that, The current d-axis voltage and the current q-axis voltage are processed to obtain a processed voltage signal, specifically including: Calculate the square root of the sum of the square of the current d-axis voltage and the square of the current q-axis voltage, and determine the result as the initial voltage signal; The initial voltage signal is processed to obtain the processed voltage signal.

6. The compressor control method according to claim 5, characterized in that, The initial voltage signal is processed to obtain the processed voltage signal, specifically including: Acquire multiple initial voltage signals within the currently set time period; The average value of the multiple initial voltage signals within the current set time period is determined as the processed voltage signal; Alternatively, the maximum value among the multiple initial voltage signals within the currently set time period can be determined as the processed voltage signal; Alternatively, the larger of the average value of the multiple initial voltage signals within the current set time period and the average value of the multiple initial voltage signals within the previous set time period can be determined as the processed voltage signal. Alternatively, the larger of the maximum value among the multiple initial voltage signals within the current set time period and the maximum value among the multiple initial voltage signals within the previous set time period can be determined as the processed voltage signal.

7. The compressor control method according to claim 5, characterized in that, The initial voltage signal is processed to obtain the processed voltage signal, specifically including: Acquire multiple initial voltage signals within the current electrical cycle; the electrical cycle is the period during which the compressor's stator current changes from 0° to 360°. The average value of the multiple initial voltage signals within the current electrical cycle is determined as the processed voltage signal; Alternatively, the maximum value among the multiple initial voltage signals within the current electrical cycle can be determined as the processed voltage signal; Alternatively, the larger of the average value of the multiple initial voltage signals in the current electrical cycle and the average value of the multiple initial voltage signals in the previous electrical cycle can be determined as the processed voltage signal. Alternatively, the larger of the maximum value among the multiple initial voltage signals in the current electrical cycle and the maximum value among the multiple initial voltage signals in the previous electrical cycle can be determined as the processed voltage signal.

8. The compressor control method according to claim 5, characterized in that, The initial voltage signal is processed to obtain the processed voltage signal, specifically including: Acquire multiple initial voltage signals within the current mechanical cycle; the mechanical cycle is the cycle in which the compressor rotor rotates from 0° to 360°. The average value of the multiple initial voltage signals within the current mechanical cycle is determined as the processed voltage signal; Alternatively, the maximum value among the multiple initial voltage signals within the current mechanical cycle can be determined as the processed voltage signal; Alternatively, the larger of the average value of the multiple initial voltage signals in the current mechanical cycle and the average value of the multiple initial voltage signals in the previous mechanical cycle can be determined as the processed voltage signal. Alternatively, the larger of the maximum value among the multiple initial voltage signals in the current mechanical cycle and the maximum value among the multiple initial voltage signals in the previous mechanical cycle can be determined as the processed voltage signal.

9. A compressor control device, characterized in that, The control device includes: The three-phase current acquisition unit is used to acquire the current three-phase current of the compressor; The bus voltage adjustment command acquisition unit is used to acquire the current d-axis voltage and the current q-axis voltage based on the current three-phase current, process the current d-axis voltage and the current q-axis voltage to obtain the processed voltage signal, and multiply the processed voltage signal by the reciprocal of the adjustment coefficient, and the product is determined as the current bus voltage adjustment command. The control mode determination unit is used to determine whether the compressor is in the field weakening control mode; The first control unit is configured to execute the following first control process when the compressor is in the field weakening control mode: limiting the current bus voltage adjustment command using the current limiting value to obtain the limited bus voltage command, which is then determined as the current actual bus voltage command; performing power factor correction control based on the current actual bus voltage command; the current limiting value includes the current maximum limiting value, which is determined based on the current speed of the compressor, and the current maximum limiting value and the current speed satisfy a positive correlation. The second control unit is used to execute the following two control processes when the compressor is in non-field weakening control mode: applying a fixed limiting value to the current adjustment bus voltage command to obtain the limited bus voltage command, and determining it as the current actual bus voltage command; performing power factor correction control according to the current actual bus voltage command; the fixed limiting value includes a fixed maximum limiting value.

10. A variable frequency air conditioner, comprising a compressor, characterized in that, The variable frequency air conditioner also includes the compressor control device described in claim 9.

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