Air conditioner

Abstract

The invention discloses an air conditioner. The air conditioner comprises a load; the input end of the power circuit is connected with a single-phase power grid, and the output end of the power circuit is connected to the load; the power grid parameter detection module comprises an orthogonal signal generator which is used for converting the alternating-current input power grid voltage into orthogonal voltage signals V alpha and V beta under an alpha-beta shaft system; the Park conversion module is used for converting the orthogonal voltage signal into voltage components Vd and Vq under a synchronous rotating coordinate system; the per-unit phase locking module is configured to perform filtering on the voltage component Vd to obtain a power grid voltage amplitude Vs; performing per-unit processing on the voltage component Vq to obtain a per-unit value, and performing filtering and PI adjustment on the per-unit value in sequence to obtain a power grid voltage frequency omega; and performing integral adjustment on the frequency omega to obtain a power grid voltage phase theta. The power grid parameter detection module is used for power grid parameter information detection, and has the advantages of being high in anti-interference capacity and high in reliability.

Description

Technical Field

[0001] The invention belongs to the technical field of air conditioning, and in particular relates to an air conditioner. Background Art

[0002] PG (Pulse Generator) motor is a motor that controls the drive voltage of the motor by controlling the conduction time of the solid-state relay. Because it has the function of stepless speed regulation and is relatively cheap, it is widely used in electrical equipment such as air conditioners. Air conditioners usually also include a power supply circuit, which is connected to the power grid to supply power to loads including PG motors.

[0003] In practical applications, air conditioners generally need to detect the parameters of the grid voltage, such as (amplitude, frequency, phase), and use the detection results as a reference for corresponding control or processing. The purpose of detection is to keep the control or processing synchronized with the grid. Incorrect detection may cause a power short circuit or overvoltage, resulting in serious accidents. Inaccurate detection will lead to a decrease in system performance.

[0004] The current conventional grid phase detection method is based on the grid voltage zero-crossing point, and detects the zero-crossing point through the positive and negative changes of the grid voltage, thereby obtaining the grid phase. However, the prominent problem of the current method is that when the grid voltage is disturbed or oscillated near the zero-crossing point, such as the grid voltage itself is distorted, or the input power supply is an unstable power supply such as a diesel generator, or the detection circuit itself is subject to electromagnetic interference, etc., it is very easy to have a zero-crossing detection error, resulting in control abnormality and damage to the system reliability.

[0005] In response to this problem, there is a technical solution that uses a phase-locked loop to detect the grid voltage. It does not rely on the zero-crossing point of the grid voltage, has strong anti-interference ability and high reliability. However, due to the fact that the actual grid conditions are not fixed, it is impossible to guarantee that the phase-locked loop has the same dynamic response and stability. When the grid conditions change drastically, it may cause delays and distortion, resulting in a decrease in tracking performance, affecting measurement accuracy, and prone to control abnormalities. Summary of the invention

[0006] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end,

[0007] According to an embodiment of the present disclosure, there is provided an air conditioner, comprising:

[0008] chassis;

[0009] A load is disposed in the housing, wherein the load comprises a PG motor;

[0010] A power supply circuit, whose input end is connected to a single-phase power grid, and whose output end is connected to the load, wherein the power supply circuit is used to convert a grid voltage of the single-phase power grid into a DC bus voltage to supply power to the load;

[0011] A control module, connected to the power circuit and the load, for issuing a control signal to drive the PG motor to operate;

[0012] The grid parameter detection module is connected between the input end of the power supply circuit and the control module to detect the amplitude, frequency and phase of the grid voltage, and includes:

[0013] The orthogonal signal generator has an input end connected to the single-phase power grid to convert the AC input power grid voltage into an orthogonal voltage signal V under the α-β axis system. α and V β ;

[0014] The Park transformation module has an input end connected to the output end of the orthogonal signal generator to transform the orthogonal voltage signal into a voltage component V in a synchronous rotating coordinate system. d and V q ;

[0015] A per-unit phase-locked module, whose input end is connected to the output end of the Park transformation module; the per-unit phase-locked module is configured as follows:

[0016] For the voltage component V d Filter and obtain the grid voltage amplitude V s ;

[0017] For the voltage component V q Perform per-unit processing to obtain a per-unit value, and perform filtering and PI adjustment on the per-unit value in turn to obtain a grid voltage frequency ω;

[0018] The frequency ω is integrally regulated to obtain the grid voltage phase θ.

[0019] The above technical solution has the following advantages or beneficial effects: the grid parameter detection module of the above structure is used to detect the parameter information of the single-phase grid, which has the advantages of strong anti-interference ability and high reliability, and provides more basis for the control of the air conditioner. Since the actual grid conditions are not fixed, it is impossible to ensure that the phase-locked loop has the same dynamic response and stability. Therefore, the above-mentioned setting of the per-unit phase-locked loop, when the amplitude of the input voltage of the single-phase grid is different, uses the same set of PI parameters to ensure the same dynamic response and stability, so that the air conditioner can quickly respond to grid changes, optimize cooling or heating performance, and improve user comfort.

[0020] According to an embodiment of the present disclosure, the power grid parameter detection module further includes:

[0021] A complex coefficient filter is connected between the orthogonal signal generator and the Park transformation module; the complex coefficient filter is configured to: α and V β Filter to obtain the orthogonal signal V α-filt and V β-filt ; The V α-filt and V β-filt Replace the V α and V β As input to the Park transformation module;

[0022] The grid voltage frequency ω is fed back to the complex coefficient filter to update its center frequency in real time.

[0023] The above technical solution has the following advantages or beneficial effects: by setting a complex coefficient filter, the influence of the interference of the AC input grid voltage signal is effectively suppressed, and the phase and frequency of the grid can be measured more accurately.

[0024] According to an embodiment of the present disclosure, the orthogonal signal V is calculated by a first operation logic α-filt and V β-filt ,

[0025] The first logical operation is:

[0026] Among them, ω e is the center frequency of the complex coefficient filter, and ω e =ω,ω c is the cutoff frequency of the complex coefficient filter, s is the Laplace operator, and j is the imaginary number obtained by coupling the variables of the α-β axis system.

[0027] The above technical solution has the following advantages or beneficial effects: the grid voltage frequency is used as the set center frequency, so that the input signal of the complex coefficient filter has no amplitude attenuation and phase lag at this frequency, thereby retaining the characteristics of the input signal at this frequency, ensuring that the subsequent phase-locked loop can accurately lock the phase and frequency.

[0028] According to an embodiment of the present disclosure, the per-unit phase-locked module includes:

[0029] A first filter is connected to the Park transformation module to d Perform filtering processing;

[0030] A per-unit unit, whose input terminal is connected to the Park transformation module, for generating the per-unit value;

[0031] A second filter connected to the output end of the per-unit unit to filter the per-unit value;

[0032] A PI regulator is connected to the second filter to perform PI regulation on the filtered per-unit value to obtain a grid voltage frequency ω;

[0033] An integrator is connected to the output end of the PI regulator, performs integral regulation on the grid voltage frequency ω and outputs the grid voltage phase θ; wherein the phase θ is fed back to the Park transformation module.

[0034] The above technical solution has the following advantages or beneficial effects: by setting the first filter and the second filter, high-frequency noise and interference in the input signal of the phase-locked loop can be effectively removed. The phase-locked loop of this structure can provide efficient, stable and accurate phase and frequency detection and adjustment.

[0035] According to an embodiment of the present disclosure, the PI regulator includes a PI regulation link and a first adder, and the output of the PI regulation link is proportional to the bias input frequency ω offset , after being added by the first adder, the grid voltage frequency ω is obtained; wherein, ω offset =2π*F1, F1 is 55Hz.

[0036] The above technical solution has the following advantages or beneficial effects: the above setting is compatible with 50Hz and 60Hz power systems, so that the phase-locked loop can work stably in power grids with different frequencies, thereby improving the applicability of the air conditioner.

[0037] According to an embodiment of the present disclosure, the first filter and / or the second filter is a low-pass filter.

[0038] The above technical solution has the following advantages or beneficial effects: the low-pass filter can effectively filter out high-frequency noise in the input signal of the phase-locked loop, reduce the oscillation and instability of the system, and thus enhance the stability of the phase-locked loop.

[0039] According to an embodiment of the present disclosure, the grid voltage frequency ω is fed back to the orthogonal signal generator.

[0040] The above technical solution has the following advantages or beneficial effects: the feedback frequency ω helps to adjust the phase and frequency of the orthogonal signal in real time, ensuring that the generated signal is consistent with the actual power grid signal, thereby reducing errors.

[0041] According to an embodiment of the present disclosure, the air conditioner includes an outdoor electric control board, and the power supply circuit and the power grid parameter detection module are integrated on the outdoor electric control board.

[0042] The above technical solution has the following advantages or beneficial effects: integrating the power grid parameter detection module with the power supply circuit can simplify wiring, reduce the complexity and installation cost of the air conditioning system, and improve the compactness of the overall design. At the same time, performing power grid parameter detection on the outdoor electric control panel can quickly respond to power grid changes, adjust the operating status of the air conditioner in time, and ensure the safety and stable operation of the equipment.

[0043] According to an embodiment of the present disclosure, the power supply circuit includes:

[0044] A rectifier module, used to receive the grid voltage and output a DC voltage;

[0045] A PFC circuit, whose input end is connected to the rectifier module and whose output end is connected to the load, for providing a DC bus voltage to the load;

[0046] The control module is connected to the controlled end of the PFC circuit and is used to adjust the operating parameters of the PFC circuit according to the parameter information detected by the power grid parameter detection module.

[0047] The above technical solution has the following advantages or beneficial effects: by real-time monitoring of grid parameter information, the operating state of the PFC circuit can be dynamically adjusted to cope with changes in the grid and ensure that the load always operates under optimal working conditions.

[0048] According to an embodiment of the present disclosure, there is also provided an air conditioner, comprising:

[0049] chassis;

[0050] A load is disposed in the housing, wherein the load comprises a PG motor;

[0051] A controller is connected between the single-phase power grid and the load, and the controller is configured to:

[0052] Converting the grid voltage of the single-phase grid into a DC bus voltage to supply power to the load;

[0053] The grid voltage is converted into a quadrature voltage signal V α and V β ;

[0054] The orthogonal voltage signal V α and V β Perform vector transformation operation to generate the voltage component V based on the synchronous rotating coordinate system d and V q ;

[0055] For the voltage component V d Perform filtering to obtain the grid voltage amplitude V s ;

[0056] For the voltage component V q The per-unit value is obtained by performing per-unit processing and is subjected to PI adjustment to obtain the grid voltage frequency ω; at the same time, the frequency ω is integrally adjusted to obtain the grid voltage phase θ.

[0057] The above technical solution has the following advantages or beneficial effects: the above method is used to detect the parameter information of the single-phase power grid, which has the advantages of strong anti-interference ability and high reliability, and provides more basis for the control of the air conditioner. At the same time, during the detection process, the voltage component V q By performing normalization processing and using the same set of PI parameters in PI regulation when the amplitude of the input voltage of the single-phase power grid is different, the same dynamic response and stability can be guaranteed, so that the air conditioner can respond quickly to changes in the power grid, optimize cooling or heating performance, and improve user comfort. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 is a structural block diagram of an air conditioner according to an embodiment of the present disclosure;

[0059] Figure 2 is a schematic structural diagram of a refrigerant circuit according to an embodiment of the present disclosure;

[0060] Figure 3 is a schematic diagram of the circuit structure of an air conditioner according to an embodiment of the present disclosure;

[0061] Figure 4 is a schematic diagram of the hardware structure of an outdoor electric control panel according to an embodiment of the present disclosure;

[0062] Figure 5 is a structural schematic diagram of a power grid parameter detection module according to an embodiment of the present disclosure;

[0063] Figure 6 is the control logic of the phase-locked module in accordance with the embodiment of the present disclosure;

[0064] Figure 7 is a hardware configuration block diagram of an air conditioner according to an embodiment of the present disclosure;

[0065] Figure 8 is a structural schematic diagram of a power grid parameter detection module according to another embodiment of the present disclosure;

[0066] Fig. 9 It is a structural schematic diagram of the implementation principle of the complex coefficient filter according to the embodiment of the present disclosure;

[0067] Fig.10 is a schematic diagram of connection between a power supply circuit and a load according to an embodiment of the present disclosure;

[0068] Fig.11It is a simulation waveform of a power grid parameter detection module detecting power grid parameter information according to an embodiment of the present disclosure;

[0069] Fig.12 It is the control logic of power grid parameter information detection according to the embodiment of the present disclosure.

[0070] In the above figures: air conditioner 10; indoor unit 1; indoor heat exchanger 11; indoor fan 12; outdoor unit 2; outdoor heat exchanger 21; compressor 22; outdoor fan 23; throttling device 3; refrigerant circuit 4; controller 5; power supply circuit 51; rectifier module 511; PFC circuit 512; control module 52; power grid parameter detection module 53; orthogonal signal generator 531; Park transformation module 532; per-unit phase-locked module 533; complex coefficient filter 534; four-way valve 6; load 7. DETAILED DESCRIPTION

[0071] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0072] Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. In addition, it can also be understood that although the efforts made in this development process may be complicated and lengthy, for ordinary technicians in this field related to the content disclosed in this application, some changes in design, manufacturing or production based on the technical content disclosed in this application are just conventional technical means, and should not be understood as insufficient content disclosed in this application.

[0073] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those of ordinary skill in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0074] The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "plurality" involved in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the previous and subsequent associated objects are in an "or" relationship. The terms "first", "second", "third" and the like involved in this application are merely used to distinguish similar objects, and do not represent a specific ordering of the objects.

[0075] The present invention provides an air conditioner 10, as shown below Figures 1 to 12 The air conditioner 10 provided in the present application is described.

[0076] In an exemplary embodiment of the air conditioner 10 provided by the present invention, referring to Figure 1 The air conditioner 10 may include an indoor unit 1. The indoor unit 1 is usually arranged indoors for exchanging heat with the indoor environment.

[0077] Among them, the indoor unit 1 can be set as a wall-mounted type, a cabinet type, a ceiling unit, a duct unit, a curtain unit, a hanging unit, etc.

[0078] The air conditioner 10 may include an outdoor unit 2. The outdoor unit 2 is usually disposed outdoors and is used to bring indoor heat to the outdoors.

[0079] The indoor unit 1 and the outdoor unit 2 may be configured as an integrated unit or a split unit.

[0080] The air conditioner may include a casing, wherein the casing may include an indoor casing and / or an outdoor casing.

[0081] The indoor casing forms the appearance of the indoor unit 1. An installation cavity is formed in the indoor casing. The installation cavity is used to accommodate and fix various components in the indoor unit 1.

[0082] The indoor housing may include an air inlet which is communicated with the installation cavity and serves as an inlet for air outside the indoor housing to flow into the installation cavity, allowing indoor wind to enter the installation cavity through the air inlet.

[0083] The indoor housing may include an air outlet which is in communication with the installation cavity and serves as an outlet for the heat exchange airflow in the indoor housing to flow out, allowing the airflow in the installation cavity to flow out through the air outlet.

[0084] The indoor unit 1 may include an indoor heat exchanger 11. The indoor heat exchanger 11 is disposed in the installation cavity and is used for performing heat exchange with the airflow in the indoor casing.

[0085] The indoor unit 1 may include an indoor fan 12. The indoor fan 12 rotates to drive the air in the installation cavity to flow from the air inlet to the air outlet.

[0086] The indoor unit 1 may include an indoor fan, and the indoor fan is disposed in the installation cavity.

[0087] The indoor unit 1 may include a first motor, wherein the first motor is electrically connected to the indoor fan 12 to drive the indoor fan to rotate.

[0088] The outdoor housing forms the appearance of the outdoor unit 2. The outdoor housing has a receiving space inside, and the receiving space is used to accommodate and fix various components in the outdoor unit 2.

[0089] The outdoor housing may include an outdoor air inlet, which may be in communication with the accommodation space and may be used to introduce outdoor air into the accommodation space.

[0090] The outdoor housing may include an outdoor air outlet, which may be in communication with the accommodation space and may be used to guide the air in the accommodation space out of the accommodation space.

[0091] The outdoor unit 2 may include an outdoor heat exchanger 21. The outdoor heat exchanger 21 may be disposed in the accommodation space.

[0092] The outdoor unit 2 may include an outdoor fan 23. The rotation of the outdoor fan 23 causes outdoor air to enter the accommodating chamber from the outdoor air inlet to exchange heat with the outdoor heat exchanger 21, and the outdoor air after heat exchange flows out of the accommodating chamber from the outdoor air outlet.

[0093] The outdoor fan 23 may include an outdoor fan, and the outdoor fan may be disposed in the accommodating space.

[0094] The outdoor fan 23 may include a second motor, wherein the second motor is electrically connected to the outdoor fan to drive the outdoor fan to rotate.

[0095] The air conditioner 10 may include a compressor 22 provided in the outdoor unit 2 .

[0096] The compressor 22 is used to compress the refrigerant gas in a low-temperature and low-pressure state into a refrigerant gas in a high-temperature and high-pressure state, and discharge the compressed refrigerant gas to the condenser 42. The compressor may be a variable frequency compressor.

[0097] The compressor 22 may include a third electric machine configured as a power source for the compressor 22 .

[0098] The air conditioner 10 may include a throttling device 3. The throttling device 3 is used for throttling. The throttling device 3 may be provided in the indoor unit 1 or the outdoor unit 2.

[0099] The air conditioner 10 may include a refrigerant circuit 4. Figure 2 The schematic diagram of the structure of the refrigerant circuit 4 is shown. The indoor unit 1 and the outdoor unit 2 are connected by connecting pipes to form a refrigerant circuit 4 for circulating the refrigerant.

[0100] The air conditioner 10 can perform indoor cooling or heating by circulating the refrigerant in the compressor 22, the condenser 42, the throttling device 3 and the evaporator 44 in sequence through the refrigerant circuit 4. Among them, one of the evaporator 44 and the condenser 42 is the indoor heat exchanger 11, and the other is the outdoor heat exchanger 21.

[0101] Continue to refer Figure 3 The air conditioner 10 may include a four-way valve 66. The four-way valve 66 is disposed in the outdoor unit 2 to change the flow direction of the refrigerant in the refrigerant circuit 4.

[0102] In some embodiments of the present application, the air conditioner 10 may include a controller 5. The controller 5 is electrically connected to the indoor unit 1 and the outdoor unit 2 to control the operation of various components therein, so that various components of the air conditioner 10 operate to realize various predetermined functions of the air conditioner 10.

[0103] refer to Figure 3 The controller 5 is electrically connected to at least the compressor 22 , the throttling device 3 , the indoor fan 12 and the outdoor fan 23 .

[0104] The controller 5 refers to a device that can generate an operation control signal according to the instruction operation code and the timing signal to instruct the air conditioner 10 to execute the control instruction. For example, in response to a power-on or power-off instruction received from a user, the controller 5 can execute an operation related to the object selected by the power-on or power-off instruction.

[0105] The controller 5 may include a power supply circuit 51 , wherein an input end of the power supply circuit 51 is connected to a single-phase power grid, and an output end of the power supply circuit 51 is connected to a load 7 .

[0106] The single-phase grid is used to provide a grid voltage signal of an AC input. The power supply circuit 51 is used to convert the grid voltage into a DC bus voltage, so as to provide the DC bus voltage to the load 7, thereby achieving the purpose of supplying power to the load 7.

[0107] The controller 5 may include a control module 52. The control module 52 is connected to the power circuit 51 and the load 7 to issue a control signal for driving the PG motor to operate.

[0108] It should be noted that the load 7 may include a PG motor, wherein the PG motor may be the third motor of the compressor, may be the first motor electrically connected to the indoor fan 12 , or may be the second motor electrically connected to the outdoor fan 23 .

[0109] The load 7 may include an IPM module, which is connected between the output end of the power circuit 51 and the PG motor to drive the PG motor to rotate according to the control signal. The IPM module may be an indoor fan IPM module, a compressor IPM module, or an outdoor fan IPM module.

[0110] In this embodiment, the controller 5 may include an indoor electric control board, wherein the indoor electric control board may include the indoor fan IPM module.

[0111] The indoor electric control panel is installed on the indoor casing. The indoor electric control panel is electrically connected to the indoor fan 12 and is used to at least control the operation of the indoor fan 12 .

[0112] The controller 5 may include an outdoor electric control board. The outdoor electric control board may include the compressor IPM module and the outdoor fan IPM module.

[0113] The outdoor electric control panel is installed on the outdoor housing and is electrically connected to the outdoor fan 23 and the compressor 22 , and is used to at least control the operation of the outdoor fan 23 and the compressor 22 .

[0114] It is understandable that the indoor electric control panel is communicatively connected with the outdoor electric control panel so that the indoor electric control panel and data information in the indoor electric control panel can be transmitted to each other to coordinate and manage the overall operation of the air conditioner 10.

[0115] refer to Figure 7 The outdoor electric control board may include the power supply circuit 51 and the control module 52. The control command for controlling the indoor fan 12 issued by the control module 52 is transmitted to the indoor electric control board.

[0116] The controller 5 may include a grid parameter detection module 53. The grid parameter detection module 53 is electrically connected between the input end of the power circuit 51 and the control module 52, and is used to detect the amplitude, frequency and phase of the grid voltage.

[0117] In some embodiments of the present application, the grid parameter detection module 53 may include an orthogonal signal generator 531. The input end of the orthogonal signal generator 531 is connected to the single-phase grid to convert the AC input grid voltage into an orthogonal voltage signal V under the α-β axis system. α and V β .

[0118] Specifically, the grid voltage signal V ac , it is impossible to directly obtain the input voltage under the dq axis system, so it is necessary to first use the orthogonal signal generator 531 to generate a virtual voltage signal that is orthogonal to the grid voltage.

[0119] like Figure 5As shown, after passing through the orthogonal signal generator 531, the orthogonal voltage signal V under the α-β axis system can be obtained. α and V β ; Among them, V α and V β It can be calculated using the following formulas (1) and (2).

[0120] V α =V ac (1)

[0121]

[0122] Wherein, s is the Laplace operator, ω is the grid voltage frequency, and K is the coefficient of the orthogonal signal generator 531.

[0123] From the above equations (1) and (2), it can be seen that the voltage V obtained by the orthogonal signal generator 531 is β , and the grid voltage V ac The amplitudes are the same, and the phases differ by 90 degrees, that is, the two are orthogonal signals. In the above formula, K is usually K=1.

[0124] The power grid parameter detection module 53 may include a Park transformation module 532. The input end of the Park transformation module 532 is connected to the output end of the orthogonal signal generator 531 to transform the orthogonal voltage signal output by the orthogonal signal generator 531 into a voltage component V in a synchronous rotating coordinate system. d and V q .

[0125] Specifically, the signal output by the orthogonal signal generator 531 is an orthogonal voltage signal in a two-phase stationary coordinate system (i.e., the α-β axis system), and the input required by the phase-locked loop based on the synchronous rotating coordinate system is the voltage in the dq axis system. Therefore, the coordinate transformation is required to be performed by the Park transformation module 532 to convert V α and V β Convert to V d and V q , the specific conversion relationship is shown in the following formula.

[0126]

[0127] The grid parameter detection module 53 may include a per-unit phase-locking module 533. The input end of the per-unit phase-locking module 533 is connected to the output end of the Park transformation module 532, and is used to lock the grid voltage frequency and grid voltage phase.

[0128] In this embodiment, the power grid parameter detection module 53 of the above structure is used to detect the parameter information of the single-phase power grid, which has the advantages of strong anti-interference ability and high reliability, and provides more basis for the control of the air conditioner. Since the actual power grid conditions are not fixed, it is impossible to ensure that the phase-locked loop has the same dynamic response and stability. Therefore, the above-mentioned setting of the per-unit phase-locked loop, when the amplitude of the input voltage of the single-phase power grid is different, uses the same set of PI parameters to ensure the same dynamic response and stability, so that the air conditioner can quickly respond to power grid changes, optimize cooling or heating performance, and improve user comfort.

[0129] refer to Figure 6 The per-unit phase-locked module 533 is configured as follows:

[0130] Filtering the voltage component Vd to obtain the grid voltage amplitude Vs (step S10);

[0131] The voltage component Vq is normalized to obtain a per-unit value, and the per-unit value is PI-regulated to obtain the grid voltage frequency ω (step S20);

[0132] After executing step S20, the frequency ω is integrally adjusted to obtain the grid voltage phase θ (step S30).

[0133] Specifically, the Park transformation module 532 outputs the voltage V in the dq axis system. d and V q After that, the per-unit phase-locked loop module can be used to obtain the parameter information of the power grid. Figure 5 As shown, specifically:

[0134] ① Park conversion module 532 outputs V d After filtering, a stable grid voltage amplitude V can be obtained. s ;

[0135] ② Park conversion module 532 outputs V q First, the per-unit processing is performed to obtain the per-unit value, and the per-unit value is filtered and PI adjusted in turn to obtain the grid voltage frequency ω.

[0136] ③ By integrally adjusting the grid voltage frequency ω, the grid phase θ can be obtained.

[0137] In some embodiments of the present application, continue to refer to Figure 5 The per-unit phase-locked module 533 may include a first filter. The first filter is connected to the Park transformation module 532 to d Filtering is performed to obtain a stable grid voltage amplitude V s ;

[0138] The per-unit phase-locked module 533 may include a per-unit unit. The input end of the per-unit phase-locked module 533 is connected to the Park transformation module 532 to generate a per-unit value. The per-unit unit is used to normalize Vq to a ratio relative to Vd. The per-unit unit DE is used to ensure that the phase-locked loop has the same dynamic response and stability when the grid input voltage amplitude is different by using the same set of PI parameters.

[0139] The per-unit phase-locked module 533 may include a second filter. The second filter is connected to the output end of the per-unit unit to filter the per-unit value, which can effectively suppress high-frequency noise and interference in the input signal and ensure the stability of the phase-locked loop.

[0140] The per-unit phase-locked module 533 may include a PI regulator. The PI regulator is connected to the second filter to perform PI regulation on the filtered per-unit value to obtain the grid voltage frequency ω.

[0141] The per-unit phase-locked module 533 may include an integrator. The integrator is connected to the output end of the PI regulator, performs integral regulation on the grid voltage frequency ω and outputs the grid voltage phase θ.

[0142] The phase θ is fed back to the Park transformation module 532. The feedback mechanism of the phase θ helps to adjust the input of the Park transformation module 532 in real time, and the PI regulator can quickly adjust the output according to the feedback signal, so that the system has a better dynamic response capability to the change of the grid frequency.

[0143] In some embodiments of the present application, the first filter and / or the second filter is a low-pass filter.

[0144] The setting of the low-pass filter can effectively remove high-frequency noise and interference in the signal, reduce the oscillation and instability of the system, ensure that the signal received by the subsequent modules is of higher quality, and thus enhance the stability of the phase-locked loop.

[0145] In some embodiments of the present application, the PI regulator may include a PI regulation link. The input end of the PI regulation link is connected to the output end of the second filter to perform PI regulation on the signal outputted by the second filter.

[0146] The PI regulator may include a first adder. The output of the PI regulation link is related to the bias input frequency ω offset , after being added by the first adder, the grid voltage frequency ω is obtained. Among them, ω offset =2π*F1, F1 is 55Hz.

[0147] Specifically, the bias input frequency ω offsetThe output introduced into the PI closed-loop control constitutes a feedforward disturbance, which is added to the output of the PI control and then input into the integral link. The output of the integral link is the phase θ of the grid voltage.

[0148] In this embodiment, F1 is set to 55 Hz, which is compatible with 50 Hz and 60 Hz power systems, so that the phase-locked loop can work stably in power grids with different frequencies, thereby improving the applicability of the air conditioner.

[0149] It can be understood that the frequency ω is the angular frequency, and the actual frequency F can be calculated according to the formula ω=2π*F.

[0150] In some embodiments of the present application, the power grid parameter detection module 53 may include a complex coefficient filter 534. The complex coefficient filter 534 is connected between the orthogonal signal generator 531 and the Park transformation module 532.

[0151] The complex coefficient filter 534 is configured to: α and V β Filter and obtain the orthogonal signal V α-filt and V β-filt ; Among them, V α-filt and V β-filt Replace V α and V β As input to the Park transformation module 532.

[0152] In this embodiment, the orthogonal voltage signal V is filtered based on complex coefficients. α and V β The filtering can effectively suppress the influence of the AC input grid voltage signal interference, and a stable and smooth V α-filt and V β-filt , so that the phase and frequency of the power grid can be measured more accurately.

[0153] refer to Figure 8 , the grid voltage frequency ω is fed back to the complex coefficient filter 534 to update its center frequency in real time.

[0154] More specifically, the complex coefficient filter 534 is configured to calculate the orthogonal signal V by a first operation logic α-filt and V β-filt ,

[0155] The first logical operation is:

[0156] Among them, ω e is the center frequency of the complex coefficient filter 534, and ω e =ω,ω cis the cutoff frequency of the complex coefficient filter 534, s is the Laplace operator, and j is the imaginary number obtained by coupling the variables of the α-β axis system with each other.

[0157] In this embodiment, the grid voltage frequency is used as the set center frequency so that the input signal of the complex coefficient filter 534 has no amplitude attenuation and phase lag at this frequency, thereby retaining the characteristics of the input signal at this frequency and ensuring that the subsequent phase-locked loop can accurately lock the phase and frequency.

[0158] For a signal with a frequency of ω, the orthogonal signal generator 531 can generate an orthogonal signal with a phase lag of 90° and a constant amplitude, but it cannot effectively filter signals of other frequencies. Therefore, when the input voltage contains harmonic components, the calculation accuracy of the final phase-locked loop will be affected. Therefore, a complex coefficient filter 534 is added.

[0159] The mathematical model of the complex coefficient filter 534 is: Based on this formula, V can be obtained by the following formulas (3) and (4): α-filt and V β-filt .

[0160]

[0161] Since the complex coefficient filter 534 has the following characteristics: at the center frequency ω e There is no amplitude attenuation and no phase

[0162] Lag; at other frequencies, it has the characteristics of a low-pass filter. Therefore, by using a complex coefficient filter 534 and setting the center frequency ω according to the grid voltage frequency ω, that is, setting ω=ω, it is possible to obtain the final orthogonal voltage signals Vα-filt and Vβ-filt without amplitude attenuation and phase lag while suppressing the harmonic components in the input voltage, thereby improving the observation accuracy.

[0163] In a specific embodiment, the difficulty of the complex coefficient filter 534 is that the denominator contains an imaginary number j, which is usually difficult to implement. The meaning of the imaginary number j is to represent an orthogonal signal with the same amplitude as the real signal and a phase difference of 90°. α and V β The fundamental wave component in satisfies this characteristic, that is, it is an orthogonal signal with equal amplitude and 90° phase difference.

[0164] Therefore, when implementing the complex coefficient filter 534, Vα and Vβ can be coupled to each other to realize the complex coefficient filter 534, that is, through the mutual coupling of the α-β axis system, the imaginary number j of the denominator in the first operation logic is realized. The principle diagram of its realization is as follows: Fig. 9 shown.

[0165] The output signal of the complex coefficient filter 534 is the voltage in the two-phase stationary coordinate system (i.e., the αβ axis system), while the required input of the phase-locked loop based on the synchronous rotating coordinate system is the voltage in the dq axis system. Therefore, Vα-filt and Vβ-filt need to be converted into Vd and Vq through the Park transformation module 532. The specific conversion relationship is shown in the following formula.

[0166]

[0167] In some embodiments of the present application, the grid voltage frequency ω is fed back to the orthogonal signal generator 531 .

[0168] In this embodiment, the feedback frequency ω helps to adjust the phase and frequency of the orthogonal signal in real time, ensuring that the generated signal is consistent with the actual grid signal, thereby reducing errors. At the same time, when the grid voltage frequency ω changes, the feedback mechanism can quickly adjust the characteristics of the generated signal, allowing the system to quickly adapt to changes and improve dynamic performance.

[0169] In some embodiments of the present application, the outdoor electric control board may include a power supply circuit 51, and the power grid parameter detection module 53 is disposed on the outdoor electric control board.

[0170] In this embodiment, the grid parameter detection module 53 is integrated with the power supply circuit 51, which can simplify the wiring, reduce the complexity and installation cost of the air conditioning system, and improve the compactness of the overall design. At the same time, the grid parameter detection on the outdoor electric control panel can quickly respond to grid changes, adjust the operating state of the air conditioner in time, and ensure the safety and stable operation of the equipment.

[0171] In some embodiments of the present application, the power circuit 51 may include a rectifier module 511. The input end of the rectifier module 511 is connected to a single-phase grid to receive an AC input grid voltage and rectify it to output a DC voltage.

[0172] The power supply circuit 51 may include a PFC (power factor correction) circuit. The input end of the PFC circuit 512 is connected to the output end of the rectifier module 511 , and the output end of the PFC circuit 512 is connected to the load 7 to provide a DC bus voltage to the load 7 .

[0173] refer to Fig.10 In this embodiment, the specific structure of the PFC circuit 512 is a conventional setting in the art and will not be described in detail here.

[0174] In some embodiments of the present application, the control module 52 is connected to the grid parameter detection module 53 and the controlled end of the PFC circuit 512 to adjust the operating parameters of the PFC circuit 512 according to the parameter information detected by the grid parameter detection module 53.

[0175] In this embodiment, by real-time monitoring of grid parameter information, the operating state of the PFC circuit 512 can be dynamically adjusted to cope with changes in the grid, and the reliability of the power supply signal output to the load 7 can be effectively improved to ensure that the load 7 always operates under the best working conditions. At the same time, the power factor can be effectively optimized, the loss of reactive power can be reduced, and the energy utilization efficiency can be improved.

[0176] refer to Fig.11 , which is a simulation waveform of the grid parameter detection module 53 in the present invention detecting grid parameter information. Among them, the blue waveform is a single-phase grid voltage, which is a 220V, 50Hz fundamental wave superimposed with a 50V, 6kHz interference signal. The red waveform is the grid voltage phase obtained by using the grid parameter detection module 53. It can be seen that at this time, the input signal is superimposed with great interference, and near the zero-crossing point of the voltage fundamental wave, the voltage repeatedly changes between positive and negative. If the grid phase is still calculated based on the zero-crossing point, estimation errors are very likely to occur.

[0177] Therefore, the air conditioner provided by the present invention uses the power grid parameter detection module 53 to detect the power grid parameter information, which is independent of the power grid voltage zero crossing point. At the same time, the addition of the relevant filtering link further suppresses the influence of input interference, has the advantages of strong anti-interference ability and high reliability, and can accurately and stably calculate the real power grid phase. Among them, the power grid parameter information can include the power grid voltage frequency and the power grid voltage amplitude, which provides more basis for air conditioning control.

[0178] In some other embodiments of the present application, the controller 5 is connected between the single-phase power grid and the load 7. Fig.12 , the controller 5 is configured as:

[0179] Converting the grid voltage of the single-phase grid into a DC bus voltage to supply power to the load 7;

[0180] Convert the grid voltage into a quadrature voltage signal V α and V β ;

[0181] For the quadrature voltage signal V α and V β Perform vector transformation operation to generate the voltage component V based on the synchronous rotating coordinate system d and V q ;

[0182] For voltage component V d Perform filtering to obtain the grid voltage amplitude V s ;

[0183] For voltage component V qThe per-unit value is obtained by performing per-unit processing and then subjected to PI adjustment to obtain the grid voltage frequency ω; at the same time, the frequency ω is integrally adjusted to obtain the grid voltage phase θ.

[0184] In the air conditioner provided in this embodiment, the above method is used to detect the parameter information of the single-phase power grid, which has the advantages of strong anti-interference ability and high reliability, and provides more basis for the control of the air conditioner. q By performing normalization processing and using the same set of PI parameters in PI regulation when the amplitude of the input voltage of the single-phase power grid is different, the same dynamic response and stability can be guaranteed, so that the air conditioner can respond quickly to changes in the power grid, optimize cooling or heating performance, and improve user comfort.

[0185] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

[0186] For the convenience of explanation, the above description has been made in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or limit the embodiments to the specific forms disclosed above. Based on the above teachings, various modifications and variations can be obtained. The selection and description of the above embodiments are to better explain the principles and practical applications, so that those skilled in the art can better use the embodiments and various different variations of the embodiments suitable for specific use considerations.

Claims

1. An air conditioner, characterized in that: include: chassis; A load is disposed in the housing, wherein the load comprises a PG motor; A power supply circuit, whose input end is connected to the single-phase power grid and whose output end is connected to the load, wherein the power supply circuit is used to convert the grid voltage of the single-phase power grid into a DC bus voltage to supply power to the load; A control module, connected to the power circuit and the load, for issuing a control signal to drive the PG motor to operate; A power grid parameter detection module is connected between the input end of the power supply circuit and the control module, and includes: The orthogonal signal generator has an input end connected to the single-phase power grid to convert the AC input power grid voltage into an orthogonal voltage signal V under the α-β axis system. α and V β ; The Park transformation module has an input end connected to the output end of the orthogonal signal generator to transform the orthogonal voltage signal into a voltage component V in a synchronous rotating coordinate system. d and V q ; A per-unit phase-locked module, whose input end is connected to the output end of the Park transformation module; the per-unit phase-locked module is configured as follows: For the voltage component V d Filter and obtain the grid voltage amplitude V s ; For the voltage component V q Perform per-unit processing to obtain a per-unit value, and filter and adjust the per-unit value in turn to obtain the grid voltage frequency ω; The frequency ω is integrally regulated to obtain the grid voltage phase θ.

2. The air conditioner according to claim 1, characterized in that: The power grid parameter detection module also includes: A complex coefficient filter is connected between the orthogonal signal generator and the Park transformation module; the complex coefficient filter is configured to: α and V β Filter to obtain the orthogonal signal V α-filt and V β-filt ; The V α-filt and V β-filt Replace the V α and V β As input to the Park transformation module; The grid voltage frequency ω is fed back to the complex coefficient filter to update its center frequency in real time.

3. The air conditioner according to claim 2, characterized in that: The quadrature signal V is calculated by the first operation logic α-filt and V β-filt , The first logical operation is: Among them, ω e is the center frequency of the complex coefficient filter and takes the grid voltage frequency, ω c is the cutoff frequency of the complex coefficient filter, s is the Laplace operator, and j is the imaginary number obtained by coupling the variables of the α-β axis system.

4. The air conditioner according to claim 1, characterized in that: The per-unit phase-locked module comprises: A first filter is connected to the Park transformation module to d Perform filtering processing; A per-unit unit, whose input terminal is connected to the Park transformation module, for generating the per-unit value; A second filter connected to the output end of the per-unit unit to filter the per-unit value; A PI regulator is connected to the second filter to perform PI regulation on the filtered per-unit value to obtain a grid voltage frequency ω; An integrator is connected to the output end of the PI regulator, performs integral regulation on the grid voltage frequency ω and outputs the grid voltage phase θ; wherein the phase θ is fed back to the Park transformation module.

5. The air conditioner according to claim 4, characterized in that: The PI regulator includes a PI regulating link and a first adder. The output of the PI regulating link is proportional to the bias input frequency ω. offset After adding by the first adder, the grid voltage frequency ω is obtained; wherein, ω o f fset =2π*F1, F1 is 55Hz.

6. The air conditioner according to claim 4, characterized in that: The first filter and / or the second filter is a low pass filter.

7. The air conditioner according to claim 1, characterized in that: The grid voltage frequency ω is fed back to the orthogonal signal generator.

8. The air conditioner according to claim 1, characterized in that: The air conditioner comprises an outdoor electric control board, and the power supply circuit and the power grid parameter detection module are integrated on the outdoor electric control board.

9. The air conditioner according to claim 1, characterized in that: The power supply circuit comprises: A rectifier module, used to receive the grid voltage and output a DC voltage; A PFC circuit, whose input end is connected to the rectifier module and whose output end is connected to the load, for providing a DC bus voltage to the load; The control module is connected to the controlled end of the PFC circuit and is used to adjust the operating parameters of the PFC circuit according to the parameter information detected by the power grid parameter detection module.

10. An air conditioner, characterized in that: include: chassis; A load is disposed in the housing, wherein the load comprises a PG motor; A controller is connected between the single-phase power grid and the load, and the controller is configured to: Converting the grid voltage of the single-phase grid into a DC bus voltage to supply power to the load; The grid voltage is converted into a quadrature voltage signal V α and V β ; The orthogonal voltage signal V α and V β Perform vector transformation operation to generate the voltage component V based on the synchronous rotating coordinate system d and V q ; For the voltage component V d Perform filtering to obtain the grid voltage amplitude V s ; For the voltage component V q The per-unit value is obtained by performing per-unit processing and is subjected to PI adjustment to obtain the grid voltage frequency ω; at the same time, the frequency ω is integrally adjusted to obtain the grid voltage phase θ.

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