Calculation method and device for input current of three-phase AC inverter

Abstract

The present application provides a method and device for calculating the input current of a three-phase AC inverter, which is applied to the field of inverter technology. The method includes: obtaining a first mapping relationship based on the effective value of the phase voltage at the rear end of the inductance of the three-phase AC inverter, the input power and the input current; obtaining a second mapping relationship based on the effective value of the phase voltage and the bus voltage; determining a target mapping relationship based on the first mapping relationship and the second mapping relationship; obtaining the current input power and the current bus voltage of the three-phase AC inverter; determining the current input current effective value of the three-phase AC inverter based on the current input power, the current bus voltage and the target mapping relationship. The method can obtain the input current effective value of the three-phase AC inverter without increasing the hardware cost.

Description

Technical Field

[0001] The present application relates to the technical field of frequency converters, and more specifically, to a method and device for calculating input current of a three-phase AC frequency converter in the technical field of frequency converters. Background Art

[0002] The three-phase AC inverter is a typical drive structure, which consists of a rectifier, a DC side reactor, a DC bus capacitor and an inverter. The input quantity of the three-phase AC inverter mainly includes the three-phase input voltage V ac , three-phase input current I ac And input power factor PF. In order to limit the voltage frequency, current frequency, overvoltage, undervoltage and overcurrent protection on the input side, it is usually necessary to obtain the input quantity.

[0003] In the related art, a current transformer is used to obtain the input current I ac , or by sampling the voltage sampling circuit V ac , and then according to the collected V ac And load power to calculate the input current I ac This method will increase the hardware cost and also require the input power factor to participate in I ac The input power factor is difficult to obtain. If a fixed value is taken, it will cause I ac The calculation error becomes larger.

[0004] So, how to obtain the input current I of the three-phase AC inverter without increasing the hardware cost? ac It has become an issue that needs to be addressed urgently. Summary of the invention

[0005] The present application provides a method and device for calculating the input current of a three-phase AC inverter. The method can obtain the input current of the three-phase AC inverter without increasing the hardware cost.

[0006] In a first aspect, a method for calculating an input current of a three-phase AC inverter is provided, the method comprising:

[0007] A first mapping relationship is obtained based on the effective value of the phase voltage at the inductor rear end of the three-phase AC inverter, the input power and the input current;

[0008] Based on the phase voltage effective value and the bus voltage, a second mapping relationship is obtained;

[0009] Based on the first mapping relationship and the second mapping relationship, a target mapping relationship is determined; wherein the target mapping relationship is used to represent a mapping relationship between a first target parameter and the input current; the first target parameter includes the bus voltage and the input power;

[0010] Obtaining the current input power and current bus voltage of the three-phase AC inverter;

[0011] Based on the current input power, the current bus voltage and the target mapping relationship, a current input current effective value of the three-phase AC inverter is determined.

[0012] In an embodiment of the present application, the first mapping relationship is the effective relationship between the effective value of the phase voltage at the rear end of the inductance of the three-phase AC inverter, the input power and the input current; the second mapping relationship is the mapping relationship between the effective value of the phase voltage and the bus voltage; therefore, based on the deduction of the first mapping relationship and the second mapping relationship, the mapping relationship between the first target parameter and the input current can be obtained; that is, the mapping relationship between the bus voltage, the input power and the input current can be obtained; thus, there is no need to introduce an input side sampling circuit, nor is there any need for advance calibration and correction, and the target mapping relationship for calculating the input current of the three-phase AC inverter can be obtained directly through derivation and calculation.

[0013] In the above scheme, since the target mapping relationship for indicating the corresponding relationship between the first target parameter and the input current can be obtained based on the input current, bus voltage and phase voltage at the rear end of the inductor of the three-phase AC inverter, when the current input power and the current bus voltage of the three-phase AC inverter are obtained, the current input current effective value of the three-phase AC inverter can be accurately calculated based on the current input power and the current bus voltage and the target mapping relationship, so there is no need to add a current transformer on the input side of the three-phase AC inverter to obtain the input current, and there is no need to add a sampling circuit based on the collected V ac And load power to calculate the input current I ac , the accurate input current can be calculated directly through the derived corresponding relationship; therefore, the above scheme can obtain the input current effective value of the three-phase AC inverter without increasing the hardware cost.

[0014] In combination with the first aspect and the above implementation manner, in some possible implementation manners, the method further includes:

[0015] Acquire the phase of the phase voltage at the rear end of the inductor and the phase of the input current at the rear end of the inductor;

[0016] Determining whether the phase of the phase voltage at the rear end of the inductor is the same as the phase of the input current;

[0017] The first mapping relationship is obtained based on the effective value of the phase voltage at the inductor rear end of the three-phase AC inverter, the input power and the input current, including:

[0018] When the phase of the phase voltage is the same as the phase of the input current, the first mapping relationship is obtained based on the effective value of the phase voltage at the rear end of the inductor, the input power and the input current.

[0019] In an embodiment of the present application, by obtaining the phase of the phase voltage at the rear end of the inductor and the phase of the input current at the rear end of the inductor, it is determined whether the phase of the phase voltage at the rear end of the inductor is the same as the phase of the input current, and when the phase of the phase voltage at the rear end of the inductor is exactly the same as the phase of the input current, a first mapping relationship is derived based on the phase voltage, input power and input current at the rear end of the inductor; since the phase of the phase voltage is the same as the phase of the input current, it indicates that the power factor of the current circuit is 1, that is, the power of the power supply is consumed by the load in the form of active power, and there is no reactive power consumption; in the above method, since the phase of the phase voltage is the same as the phase of the input current, the first mapping relationship is derived by combining the relationship between the phase of the phase voltage at the rear end of the inductor and the phase of the input current, ensuring that a relatively accurate first mapping relationship can be obtained based on the effective value of the phase voltage, the input power and the input current.

[0020] In combination with the first aspect and the above implementation manner, in some possible implementation manners, obtaining the second mapping relationship based on the effective value of the phase voltage at the rear end of the inductor and the bus voltage includes:

[0021] exist When the third mapping relationship is generated based on the average value of the effective value of the line voltage at the rear end of the inductor and the bus voltage, the third mapping relationship is used to indicate the corresponding relationship between the average value of the effective value of the line voltage at the rear end of the inductor and the bus voltage. L12-inv 、V L23-inv and V L31-inv is the line voltage at the rear end of the inductor, T is the period, and t is the time; the average value of the effective value of the line voltage is V L12-inv 、V L23-inv and V L31-inv The mean of

[0022] Obtaining the phase voltage effective value based on the average value of the line voltage effective value at the rear end of the inductor;

[0023] The second mapping relationship is obtained based on the third mapping relationship and the phase voltage effective value.

[0024] In an embodiment of the present application, when the area surrounded by the line voltage at the rear end of the inductor is equal to twice the area surrounded by the bus voltage, a third mapping relationship is generated based on the average value of the effective value of the line voltage at the rear end of the inductor and the bus voltage; based on the average value of the effective value of the line voltage at the rear end of the inductor, the effective value of the phase voltage is obtained; based on the third mapping relationship and the effective value of the phase voltage, the second mapping relationship is obtained; in the above scheme, since the third mapping relationship is generated when the relationship between the area surrounded by the line voltage at the rear end of the inductor and the area surrounded by the bus voltage satisfies a preset relationship, the third mapping relationship with higher accuracy is obtained, and thus based on the third mapping relationship with higher accuracy and the effective value of the phase voltage, a second mapping relationship with higher accuracy can be obtained, thereby improving the calculation accuracy of the target mapping relationship obtained based on the second mapping relationship.

[0025] In combination with the first aspect and the foregoing implementation manner, in some possible implementation manners, determining a target mapping relationship based on the first mapping relationship and the second mapping relationship includes:

[0026] Based on the first mapping relationship and the second mapping relationship, obtaining a target formula;

[0027] Based on the target formula, obtaining the target mapping relationship;

[0028] Wherein, the target formula is I ac = P / ( V dc );I ac represents the input current of the three-phase AC inverter, P represents the input power of the three-phase AC inverter, V dc Indicates the bus voltage of the three-phase AC inverter.

[0029] In an embodiment of the present application, a target formula is obtained based on the first mapping relationship and the second mapping relationship, and a target mapping relationship is obtained based on the target formula; since the target mapping relationship can be determined by a specific calculation formula, that is, determined by the target formula; therefore, after obtaining the current input power and the current bus voltage, the current input current effective value can be accurately calculated based on the specific calculation formula.

[0030] In combination with the first aspect and the above implementations, in some possible implementations, the first mapping relationship is obtained based on the effective value of the phase voltage, input power and input current of the inductor rear end of the three-phase AC inverter, including:

[0031] Based on the effective value of the phase voltage at the inductor rear end of the three-phase AC inverter, the input power and the input current, a first formula is obtained; wherein the first formula is used to represent the first mapping relationship;

[0032] The first formula is I ac = P / (3 V LN-inv ); where I ac represents the input current of the three-phase AC inverter, P represents the input power of the three-phase AC inverter, V LN-inv It represents the effective value of the phase voltage at the rear end of the inductor.

[0033] In an embodiment of the present application, a first formula is determined, and a first mapping relationship is represented by the first formula; since the first mapping relationship can be represented by a calculation formula with higher calculation accuracy, that is, it is represented by the first formula; therefore, based on the calculation formula of the first mapping relationship, a target mapping relationship with higher calculation accuracy can be derived and calculated, that is, the calculation formula for the effective value of the input current of the three-phase AC inverter.

[0034] In combination with the first aspect and the above implementation manner, in some possible implementation manners, obtaining a second mapping relationship based on the phase voltage effective value and the bus voltage includes:

[0035] A second formula is obtained based on the phase voltage effective value and the bus voltage; wherein the second formula is used to represent the second mapping relationship;

[0036] The second formula is V LN-inv = / 3 V dc ; Among them, V LN-inv Represents the effective value of the phase voltage at the rear end of the inductor, V dc Indicates the bus voltage of the three-phase AC inverter.

[0037] In an embodiment of the present application, a second formula is determined and the second mapping relationship is represented by the second formula; since the second mapping relationship can be represented by a calculation formula with higher calculation accuracy, the calculation formula based on the second mapping relationship can be used to derive and calculate a target mapping relationship with higher calculation accuracy, that is, the calculation formula for the effective value of the input current of the three-phase AC inverter.

[0038] In combination with the first aspect and the above implementation manner, in some possible implementation manners, generating a third mapping relationship based on the average value of the effective value of the line voltage at the rear end of the inductor and the bus voltage includes:

[0039] A third formula is obtained based on the average value of the effective value of the line voltage at the rear end of the inductor and the bus voltage; wherein the third formula is used to represent the third mapping relationship;

[0040] The third formula is V inv-avg = V dc ; Among them, Vinv-avg Represents the average value of the effective value of the line voltage at the rear end of the inductor, V dc Indicates the bus voltage of the three-phase AC inverter.

[0041] In an embodiment of the present application, a third formula for representing a third mapping relationship is determined. Since the third mapping relationship can be represented by a calculation formula with higher calculation accuracy, the calculation formula of the second mapping relationship with higher calculation accuracy can be derived and calculated based on the calculation formula of the third mapping relationship, thereby facilitating the subsequent derivation and calculation of a target mapping relationship with higher calculation accuracy.

[0042] In a second aspect, a device for calculating input current of a three-phase AC inverter is provided. The three-phase AC inverter includes: an AC power supply module, a reactance module, a rectifier module, a DC bus capacitor and an inverter module. The device includes:

[0043] A first generating module, configured to obtain a first mapping relationship based on the effective value of the phase voltage, the input power and the input current of the inductor rear end of the three-phase AC inverter; wherein the inductor rear end is the output end of the inverter;

[0044] A second generating module, configured to obtain a second mapping relationship based on the effective value of the phase voltage and the bus voltage; wherein the bus voltage is the voltage across the DC bus capacitor in the three-phase AC inverter;

[0045] A first determination module, configured to determine a target mapping relationship based on the first mapping relationship and the second mapping relationship; wherein the target mapping relationship is used to represent a mapping relationship between a first target parameter and the input current; and the first target parameter includes the bus voltage and the input power;

[0046] A first acquisition module, used to acquire the current input power and the current bus voltage of the three-phase AC inverter;

[0047] The second determination module is used to determine the current input current effective value of the three-phase AC inverter based on the current input power, the current bus voltage and the target mapping relationship.

[0048] In a third aspect, an air conditioner is provided, comprising:

[0049] A memory for storing executable program codes;

[0050] A processor is used to call and run the executable program code from the memory, so that the air conditioner executes the method in the above-mentioned first aspect or any possible implementation of the first aspect.

[0051] In a fourth aspect, a computer program product is provided, comprising: a computer program code, which, when executed on a computer, enables the computer to execute the method in the first aspect or any possible implementation of the first aspect.

[0052] In a fifth aspect, a computer-readable storage medium is provided, which stores a computer program code. When the computer program code runs on a computer, the computer executes the method in the above-mentioned first aspect or any possible implementation manner of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a structural schematic diagram of a three-phase AC inverter provided in an embodiment of the present application;

[0054] Figure 2 It is a flowchart of a method for calculating input current of a three-phase AC inverter provided in an embodiment of the present application;

[0055] Figure 3 It is a phase relationship diagram of the phase voltage at the rear end of the inductor and the input current of the phase when the three-phase AC inverter is lightly loaded, provided in an embodiment of the present application;

[0056] Figure 4 It is a phase relationship diagram of the phase voltage at the rear end of the inductor and the input current of the phase when the three-phase AC inverter provided by the embodiment of the present application is under medium load;

[0057] Figure 5 It is a phase relationship diagram of the phase voltage at the rear end of the inductor and the input current of the phase when the three-phase AC inverter is overloaded, provided in an embodiment of the present application;

[0058] Figure 6 It is a schematic diagram of the relationship between the line voltage at the rear end of the inductor and the bus voltage of a three-phase AC inverter under heavy load provided by an embodiment of the present application;

[0059] Figure 7 This is a schematic diagram of the relationship between the line voltage behind the inductor and the bus voltage of a three-phase AC inverter under light load provided by an embodiment of the present application;

[0060] Figure 8 It is a flowchart of another method for calculating the input current of a three-phase AC inverter provided in an embodiment of the present application;

[0061] Fig. 9 It is a structural schematic diagram of a device for calculating input current of a three-phase AC inverter provided in an embodiment of the present application;

[0062] Fig.10 It is a structural schematic diagram of an air conditioner provided in an embodiment of the present application. DETAILED DESCRIPTION

[0063] The technical solution in the present application will be described clearly and in detail below in conjunction with the accompanying drawings. In the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B: "and / or" in the text is only a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0064] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as suggesting or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0065] Figure 1 A schematic diagram of the structure of a three-phase AC inverter provided in an embodiment of the present application.

[0066] like Figure 1 As shown, the three-phase AC inverter includes an AC power module 110, a reactance module 120, a rectifier module 130, a DC bus capacitor C, and an inverter module 140. Among them, the first end of the rectifier module 130 is connected to the AC power module 110 through the reactance module 120, the second end of the rectifier module 130 is connected to the first end of the DC bus capacitor C and the first end of the inverter module 140, and the third end of the rectifier module can be connected to the second end of the DC bus capacitor and the second end of the inverter module 140. The third end of the inverter module 140 can be connected to a load (such as a motor).

[0067] Exemplarily, the rectifier module 130, i.e., the rectifier, is used to convert the three-phase AC power into DC power; the DC link usually includes a large-capacity electrolytic capacitor (such as Figure 1 The capacitor C in the inverter module 140 is used to smooth the rectified DC voltage; the inverter module 140, that is, the inverter, is used to convert the DC power into a three-phase AC power with adjustable frequency and voltage.

[0068] Optionally, the three-phase AC inverter further includes a filter inductor, which is installed at the output end of the inverter and is used to filter out high-frequency harmonics in the inverter output, reduce fluctuations in the output current, and improve the quality of the current.

[0069] It should be noted that the above Figure 1 The AC power supply is a three-phase AC power supply as an example for illustration, but the present application does not limit the type of the AC power supply. Figure 1A three-phase AC inverter is used as an example for explanation, but the present application does not limit the type and specific structure of the AC inverter. For example, it can be applied to a three-phase AC power supply passive PFC inverter.

[0070] Above Figure 1 The three-phase AC inverter shown can control the output voltage of the AC power supply. Figure 1 The speed of the motor in.

[0071] The following will describe in detail the method for calculating the input current of the three-phase AC inverter provided in the embodiment of the present application in conjunction with the above-mentioned drawings.

[0072] Figure 2 It is a flowchart of a method for calculating the input current of a three-phase AC inverter provided in an embodiment of the present application.

[0073] For example, Figure 2 The calculation method of the input current of the three-phase AC inverter shown in FIG. Figure 1 The process is performed by the three-phase AC inverter shown; or by an electronic device with processing functions, such as an air conditioner.

[0074] like Figure 2 As shown, the method may include S201 to S205, and S201 to S205 are described in detail below.

[0075] S201, obtaining a first mapping relationship based on the effective value of the phase voltage at the inductor rear end of the three-phase AC inverter, the input power and the input current.

[0076] Among them, the inductor back end of the three-phase AC inverter refers to the part after the inverter output end, that is, the circuit before the inverter outputs to the motor.

[0077] Among them, the input current of the above three-phase AC inverter can be understood as follows Figure 1 The current provided by the AC power module 110 is shown.

[0078] Exemplarily, a first mapping relationship is obtained based on the phase voltage, input power and input current at the rear end of the inductor; wherein the first mapping relationship is used to indicate the corresponding relationship between the effective value of the phase voltage, input power and input current at the rear end of the inductor.

[0079] Optionally, the first mapping relationship is obtained based on the phase voltage, input power and input current at the rear end of the inductor, which can be understood as obtaining the first mapping relationship based on the phase of the phase voltage at the rear end of the inductor and the phase of the input power and the relationship between the input power.

[0080] It should be noted that phase voltage refers to the voltage between any phase (live wire) and the neutral wire, such as Figure 1The phase voltages at the rear end of the inductor in the reactance module 120 are V L1-inv 、V L2-inv and V L3-inv .

[0081] In one implementation, the embodiment of the present application may further include the following steps:

[0082] Obtaining the phase of the phase voltage at the rear end of the inductor and the phase of the input current;

[0083] Determine whether the phase of the phase voltage at the rear end of the inductor is the same as the phase of the input current.

[0084] Optionally, a waveform of the phase voltage at the rear end of the inductor and a waveform of the input current of the inductor can be obtained through simulation, and whether the phase of the phase voltage is the same as the phase of the input current can be judged based on the waveform of the phase voltage and the waveform of the input current; when the two waveforms are completely in phase, it is considered that the phase difference angle between the phase of the phase voltage and the phase of the input current is 0, that is, the phase of the phase voltage is the same as the phase of the input current.

[0085] It should be noted that in an AC circuit, the phase relationship between voltage and current reflects the way energy is exchanged. When the two are in phase, it means that there is only energy consumption in the circuit (such as heating of resistors), and there is no process of energy conversion between electric field and magnetic field, that is, there is no reactive power exchange.

[0086] Accordingly, the step of obtaining the first mapping relationship based on the phase voltage, input power and input current at the rear end of the inductor may specifically include:

[0087] When the phase of the phase voltage at the rear end of the inductor is completely the same as the phase of the input current, a first mapping relationship is obtained based on the phase voltage at the rear end of the inductor, the input power and the input current.

[0088] It should be understood that when the phase of the phase voltage at the rear end of the inductor is exactly the same as the phase of the input current, the phase power factor between the two is equal to 1, indicating that all the power provided by the power supply is consumed by the load in the form of active power, and there is no reactive power loss, which means that the power system operates with high efficiency and full energy utilization.

[0089] It should be noted that the line voltage refers to the voltage between two live wires (usually marked as L1, L2, and L3 in a three-phase system); Figure 1 As shown, it is assumed that the phase voltages at the rear end of the inductor in the reactance module 120 are V L1-inv 、V L2-inv and V L3-inv , then the line voltages at the rear end of the inductor are V L12-inv 、V L23-inv and V L31-inv .

[0090] Based on the above Figure 1 The structural schematic diagram of the three-phase AC inverter shown; Figure 3 1 is a phase relationship diagram of the phase voltage at the rear end of the inductor and the input current of the phase when the three-phase AC inverter is lightly loaded, provided in an embodiment of the present application. Figure 3 As shown, the abscissa of the first figure is time (t), and the ordinate is phase voltage; the abscissa of the second figure is time (t), and the ordinate is current I L1 , the phase voltage V at the rear end of the inductor L1-inv The input current I L1 The phases are completely consistent.

[0091] Based on the above Figure 1 The structural schematic diagram of the three-phase AC inverter shown; Figure 4 1 is a phase relationship diagram of the phase voltage at the rear end of the inductor and the input current of the phase when the three-phase AC inverter is under medium load provided by the embodiment of the present application. Figure 4 As shown, the abscissa of the first figure is time (t), and the ordinate is phase voltage; the abscissa of the second figure is time (t), and the ordinate is current I L1 , the phase voltage V at the rear end of the inductor L1-inv The input current I L1 The phases are completely consistent.

[0092] Based on the above Figure 1 The structural schematic diagram of the three-phase AC inverter shown; Figure 5 1 is a phase relationship diagram of the phase voltage at the rear end of the inductor and the input current of the phase when the three-phase AC inverter is overloaded, provided in an embodiment of the present application. Figure 5 As shown, the abscissa of the first figure is time (t), and the ordinate is phase voltage; the abscissa of the second figure is time (t), and the ordinate is current I L1 , the phase voltage V at the rear end of the inductor L1-inv The input current I L1 The phases are completely consistent.

[0093] Through the above Figures 3 to 5 It can be found that the phase voltage at the rear end of the capacitor is a standard four-level step wave when overloaded. When the load of the three-phase AC inverter is heavier, the harmonic content of the input current is lower, that is, it is closer to a sine wave.

[0094] Based on the above-mentioned characteristic that the phase voltage at the rear end of the light load, medium load and heavy load inductor is completely consistent with the phase of the input current of this phase, that is, the phase power factor between the two is equal to 1, the first mapping relationship can be obtained based on the phase voltage at the rear end of the inductor, the input power and the input current.

[0095] It should be noted that when the phase voltage and input current are in phase, the power calculation in the AC circuit can be simplified and the energy transmission efficiency in the circuit can be maximized. In practical applications, by ensuring that the voltage and current are in phase, the analysis and design process can be simplified; it can be understood that when the phase voltage and input current are in phase, the input power = phase voltage effective value Input current effective value. Therefore, in order to ensure that the corresponding relationship between the input power, the phase voltage effective value and the input current effective value is established, it is necessary to ensure that the phases of the phase voltage and the input current are the same, thereby improving the accuracy of the first mapping relationship.

[0096] In an embodiment of the present application, the phase of the phase voltage at the rear end of the inductor and the phase of the input current of the inductor are obtained to determine whether the phase of the phase voltage at the rear end of the inductor is the same as the phase of the input current, and when the phase of the phase voltage at the rear end of the inductor is exactly the same as the phase of the input current, a first mapping relationship is derived based on the phase voltage at the rear end of the inductor, the input power and the input current; in the above method, when the phase of the phase voltage is the same as the phase of the input current, the first mapping relationship is derived by combining the relationship between the phase of the phase voltage at the rear end of the inductor and the phase of the input current, ensuring that a relatively accurate first mapping relationship can be obtained based on the effective value of the phase voltage, the input power and the input current.

[0097] In one implementation, the first mapping relationship is obtained based on the effective value of the phase voltage at the inductor rear end of the three-phase AC inverter, the input power and the input current, which may specifically include:

[0098] Based on the effective value of the phase voltage at the rear end of the inductor of the three-phase AC inverter, the input power and the input current, a first formula is obtained; wherein the first formula is used to represent the first mapping relationship; the first formula is:

[0099] I ac = P / (3 V LN-inv )(1)

[0100] Among them, I ac Indicates the effective value of input current, P indicates input power, V LN-inv Indicates the effective value of the phase voltage at the end of the inductor.

[0101] It should be understood that if the input power of the three-phase AC inverter and the effective value of the phase voltage at the rear end of the inductor are obtained, the effective value of the input current can be calculated based on the first formula shown in the above formula (1).

[0102] In an embodiment of the present application, since the first mapping relationship can be expressed by a calculation formula with higher calculation accuracy, the calculation formula based on the first mapping relationship can be used to derive a target mapping relationship with higher accuracy, that is, the calculation formula for the effective value of the input current of the three-phase AC inverter.

[0103] S202: Obtain a second mapping relationship based on the effective value of the phase voltage and the bus voltage.

[0104] The bus voltage is the voltage across the DC bus capacitor in the three-phase AC inverter; the second mapping relationship is used to indicate the corresponding relationship between the effective value of the phase voltage and the bus voltage.

[0105] In one implementation, the step of obtaining the second mapping relationship based on the effective value of the phase voltage at the rear end of the inductor and the bus voltage may specifically include the following steps (a) to (c):

[0106] (a) In When , a third mapping relationship is generated based on the average value of the effective value of the line voltage at the rear end of the inductor and the bus voltage.

[0107] The third mapping relationship is used to indicate the corresponding relationship between the average value of the effective value of the line voltage at the rear end of the inductor and the bus voltage.

[0108] Optionally, when the AC inverter is a multi-phase AC inverter, Figure 1 As shown, the reactance module 120 includes three inductors. At this time, the area surrounded by the line voltage at the rear end of the inductor is equal to twice the area surrounded by the bus voltage. It can be understood that the sum of the areas surrounded by the line voltage at the rear end of each inductor of the three inductors is equal to twice the area surrounded by the bus voltage. If the above relationship is expressed in the form of calculus, the line voltage at the rear end of the inductor and the bus voltage have the following corresponding relationship:

[0109] ;

[0110] Among them, V L12-inv 、V L23-inv and V L31-inv is the line voltage at the rear end of the inductor, T is the period, and t is the time; Indicates the line voltage V L12-inv area; Indicates the line voltage V L23-inv area; Indicates the line voltage V L31-inv area; Indicates bus voltage V dc area.

[0111] Based on the above Figure 1 The structural schematic diagram of the three-phase AC inverter shown; Figure 6 1 is a schematic diagram of the relationship between the line voltage at the rear end of the inductor and the bus voltage of a three-phase AC inverter under heavy load provided by an embodiment of the present application. Figure 6 As shown, the horizontal axis is time (t), and the vertical axis is line voltage. When the AC inductor is overloaded, the line voltage V L12-inv 、V L23-inv and V L31-inv It will become a standard three-level step wave, V L12-inv 、V L23-inv 、V L31-inv The area formed by the enclosure is exactly equal to the bus voltage V dc Twice the area.

[0112] Based on the above Figure 1 The structural schematic diagram of the three-phase AC inverter shown; Figure 7 1 is a schematic diagram of the relationship between the line voltage behind the inductor and the bus voltage of a three-phase AC inverter under light load provided by an embodiment of the present application. Figure 7 As shown, the horizontal axis is time (t), and the vertical axis is line voltage. When the load is light, the line voltage V L12-inv 、V L23-inv and V L31-inv Although it is not a standard step wave, V L12-inv 、V L23-inv 、V L31-inv The area formed by the enclosure is still exactly equal to the bus voltage V dc Twice the area.

[0113] It should be noted that Figure 3 and Figure 4 This is an example of the changing trend of line voltage and bus voltage; it is only used to illustrate V L12-inv 、V L23-inv 、V L31-inv The area formed by the enclosure is exactly equal to the bus voltage V dc Twice the area; this application does not impose any limitation on this.

[0114] Because under light load or heavy load, V L12-inv 、V L23-inv 、V L31-inv The area formed by the enclosure is exactly equal to the bus voltage V dc The area is twice that of the inductor, and the area is represented by the square of the effective value. Therefore, the effective value of the line voltage at the rear end of the inductor has the following relationship with the bus voltage:

[0115] V L12-inv 2 + V L23-inv 2 + V L31-inv 2 = 2V dc 2(2)

[0116] At this time, the third mapping relationship is generated based on the average value of the effective value of the line voltage at the rear end of the inductor and the bus voltage, including:

[0117] Based on the average value of the effective value of the line voltage at the rear end of the inductor and the bus voltage, a third formula is obtained; wherein the third formula is used to represent the third mapping relationship; the third formula is:

[0118] V inv-avg = V dc ; (3)

[0119] In the third formula shown in the above formula (3), V inv-avg Represents the average value of the effective value of the line voltage at the rear end of the inductor, V dc Indicates the bus voltage of the three-phase AC inverter.

[0120] It should be understood that V in the third formula above inv-avg V L12-inv 、V L23-inv 、V L31-inv The mean of , that is, the above formula (3) can be obtained based on the transformation of formula (2).

[0121] In an embodiment of the present application, since the third mapping relationship can be expressed by a calculation formula with higher calculation accuracy, the calculation formula of the second mapping relationship with higher calculation accuracy can be derived based on the calculation formula of the third mapping relationship, thereby facilitating the subsequent derivation and calculation of the target mapping relationship with higher calculation accuracy.

[0122] (b) The phase voltage effective value is obtained based on the average value of the line voltage effective value at the downstream of the inductor.

[0123] For example, since there is a quantitative relationship between the line voltage and the phase voltage: the line voltage is the phase voltage multiplied by (i.e. 1.732), the effective value of the phase voltage can be calculated based on the following formula (4):

[0124] V LN-inv = V inv-avg (4)

[0125] Among them, V LN-inv Represents the effective value of the phase voltage at the rear end of the inductor, V inv-avg Indicates the average value of the effective value of the line voltage.

[0126] (c) Based on the third mapping relationship and the phase voltage effective value, a second mapping relationship is obtained.

[0127] Exemplarily, the third mapping relationship represents the mapping relationship between the average value of the effective value of the line voltage and the bus voltage; and there is a quantitative relationship between the average value of the effective value of the line voltage and the phase voltage (as shown in formula (4)); therefore, the third mapping relationship is substituted into formula (4); that is, the mapping relationship between the effective value of the line voltage and the bus voltage can be obtained; that is, the second mapping relationship is obtained.

[0128] In an embodiment of the present application, when the area surrounded by the line voltage at the rear end of the inductor is equal to twice the area surrounded by the bus voltage, a third mapping relationship is generated based on the average value of the effective value of the line voltage at the rear end of the inductor and the bus voltage; based on the average value of the effective value of the line voltage at the rear end of the inductor, the effective value of the phase voltage is obtained; based on the third mapping relationship and the effective value of the phase voltage, the second mapping relationship is obtained; in the above scheme, since the third mapping relationship is generated when the relationship between the area surrounded by the line voltage at the rear end of the inductor and the area surrounded by the bus voltage satisfies a preset relationship, the third mapping relationship obtained has a higher accuracy, so that based on the third mapping relationship with a higher accuracy and the effective value of the phase voltage, a second mapping relationship with a higher accuracy can be obtained, thereby improving the calculation accuracy of the target mapping relationship obtained based on the second mapping relationship.

[0129] Optionally, based on the third mapping relationship and the phase voltage effective value, the second mapping relationship is obtained, which can be understood as combining the above formula (4) with formula (3), that is, it can be understood as combining the above formula (4) with the third mapping relationship to obtain the second mapping relationship.

[0130] Specifically, the second mapping relationship is obtained based on the effective value of the phase voltage at the rear end of the inductor and the bus voltage, which may specifically include:

[0131] The second formula is obtained based on the effective value of the phase voltage and the bus voltage; the second formula is used to express the second mapping relationship; the second formula is:

[0132] V LN-inv = / 3 V dc ; (5)

[0133] In the second formula above, V LN-inv Represents the effective value of the phase voltage at the rear end of the inductor, V dc Indicates the bus voltage of the three-phase AC inverter.

[0134] In an embodiment of the present application, since the second mapping relationship can be expressed by a calculation formula with higher calculation accuracy, the calculation formula based on the second mapping relationship can be used to derive and calculate a target mapping relationship with higher calculation accuracy, that is, the calculation formula for the effective value of the input current of the three-phase AC inverter.

[0135] S203: Determine a target mapping relationship based on the first mapping relationship and the second mapping relationship.

[0136] The target mapping relationship is used to indicate the corresponding relationship between the first target parameter and the input current, and the first target parameter includes the input power and bus voltage of the three-phase AC inverter.

[0137] Optionally, based on the input current, bus voltage and phase voltage of the three-phase AC inverter, a target mapping relationship is obtained, which can be understood as using the physical model of the AC side reactance circuit to derive and calculate to obtain a target mapping relationship involving the input current, bus voltage and phase voltage of the three-phase AC inverter. For details, please refer to the detailed description in the following embodiments.

[0138] Exemplarily, based on the first mapping relationship and the second mapping relationship, the target mapping relationship is determined. It can be understood that by combining the above formula (1) and formula (5), a target formula can be obtained, and the target formula is used to represent the target mapping relationship.

[0139] Specifically, obtaining the target mapping relationship based on the first mapping relationship and the second mapping relationship may specifically include:

[0140] Based on the first mapping relationship and the second mapping relationship, a target formula is obtained; based on the target formula, the target mapping relationship is obtained; wherein the target formula is:

[0141] I ac = P / ( V dc );(6)

[0142] Among them, in the target formula shown in the above formula (6), I ac It represents the effective value of the input current of the three-phase AC inverter, P represents the input power of the three-phase AC inverter, V dc Indicates the bus voltage of the three-phase AC inverter.

[0143] In an embodiment of the present application, since the target mapping relationship can be expressed by a specific calculation formula, that is, by a target formula; therefore, after obtaining the current input power and the current bus voltage, the current input current effective value can be accurately calculated based on the specific calculation formula; that is, the obtained parameters (current input power and current bus voltage) are substituted into the target formula to obtain the current input current effective value.

[0144] In an embodiment of the present application, since the first mapping relationship can be obtained based on the phase voltage at the rear end of the inductor, the input power and the input current, and the second mapping relationship can be obtained based on the effective value of the phase voltage at the rear end of the inductor and the bus voltage, the target mapping relationship can be obtained by deducing based on the first mapping relationship and the second mapping relationship, thereby eliminating the need to introduce an input side sampling circuit, and eliminating the need for advance calibration and correction. The target mapping relationship for calculating the input current of the three-phase AC inverter can be obtained directly through derivation and calculation, thereby saving hardware costs and development and testing resources.

[0145] S204, obtaining the current input power and the current bus voltage of the three-phase AC inverter.

[0146] Optionally, the current bus voltage of the three-phase AC inverter can be obtained by sampling a voltage divider circuit.

[0147] Optionally, the load power connected to the three-phase AC inverter may be obtained first, for example, Figure 1 The motor power in the three-phase AC inverter is obtained, and then the circuit loss power in the three-phase AC inverter is obtained. The sum of the circuit loss power and the load power is calculated to obtain the current input power.

[0148] S205, determining a current input current effective value of the three-phase AC inverter based on a current input power, a current bus voltage and a target mapping relationship.

[0149] For example, after obtaining the current input power and the current bus voltage, the current input power and the current bus voltage can be substituted into the above formula (6) to obtain the current input current effective value of the three-phase AC inverter.

[0150] In the embodiment of the present application, since a target mapping relationship indicating a corresponding relationship between a first target parameter and an input current can be obtained based on the input current, bus voltage, and phase voltage at the rear end of the inductor of the three-phase AC inverter, and the first target parameter includes the input power of the three-phase AC inverter and the bus voltage, when the current input power and the current bus voltage of the three-phase AC inverter are obtained, the current input current effective value of the three-phase AC inverter can be accurately calculated based on the current input power and the current bus voltage and the target mapping relationship, thereby eliminating the need to add a current transformer on the input side of the three-phase AC inverter to obtain an input current sensor, or eliminating the need to add a sampling circuit to obtain an input current sensor based on the collected V ac And load power to calculate the input current I ac , the accurate input current can be calculated directly through the derived corresponding relationship; therefore, the above scheme can obtain the input current of the three-phase AC inverter without increasing the hardware cost.

[0151] Based on the calculation method of the three-phase AC inverter input current in the above embodiment, the following is a verification result of the effect that can be achieved by the calculation method of the three-phase AC inverter input current provided by the present application, taking a 615 three-phase small multi-split air conditioner system as an example. The verification process tests the input current I of the three-phase AC inverter when the compressor (the aforementioned load) runs at different frequencies under different voltages. ac The calculated value and the input current I ac The calculated value and the actual current I a、 I b and I c The actual average value I ac For comparison, the test results are shown in Tables 1 to 3 below.

[0152] The following table 1 shows the input current I of the three-phase AC inverter calculated at different compressor frequencies when the actual input voltage of the three-phase AC inverter is 220V. ac .

[0153] Table 1

[0154]

[0155] The following table 2 shows the input current I of the three-phase AC inverter calculated at different compressor frequencies when the actual input voltage of the three-phase AC inverter is 187V. ac .

[0156] Table 2

[0157]

[0158] The following table 3 shows the input current I of the three-phase AC inverter calculated at different compressor frequencies when the actual input voltage of the three-phase AC inverter is 254V. ac .

[0159] Table 3

[0160]

[0161] From the test results, we can see that the input current I ac The error between the calculated value and the measured current average value is within 1 A. The test results confirm the effectiveness and practical application value of the present invention.

[0162] In the embodiment of the present application, since a target mapping relationship indicating a corresponding relationship between a first target parameter and an input current can be obtained based on the input current, bus voltage, and phase voltage at the rear end of the inductor of the three-phase AC inverter, and the first target parameter includes the input power of the three-phase AC inverter and the bus voltage, when the current input power and the current bus voltage of the three-phase AC inverter are obtained, the current input current effective value of the three-phase AC inverter can be accurately calculated based on the current input power and the current bus voltage and the target mapping relationship, thereby eliminating the need to add a current transformer on the input side of the three-phase AC inverter to obtain an input current sensor, or eliminating the need to add a sampling circuit to obtain an input current sensor based on the collected V ac And load power to calculate the input current I ac , the accurate input current can be calculated directly through the derived corresponding relationship; therefore, the above scheme can obtain the input current of the three-phase AC inverter without increasing the hardware cost.

[0163] Figure 8 is a flow chart of another method for calculating the input current of a three-phase AC inverter provided in an embodiment of the present application, which can be used in the above-mentioned embodiment. Figure 1 The three-phase AC inverter shown in the figure or the air conditioner or other electronic equipment equipped with the three-phase AC inverter.

[0164] For example, Figure 8 As shown, the method includes the following implementation process:

[0165] S301, obtaining the phase of the phase voltage at the rear end of the inductor of the three-phase AC inverter and the phase of the input current.

[0166] Optionally, a waveform diagram of the phase voltage at the rear end of the inductor and a waveform diagram of the input current of the inductor may be generated by simulation software, and the phase of the phase voltage at the rear end of the inductor and the phase of the input current of the inductor may be obtained based on the two waveform diagrams.

[0167] S302, determine whether the phase of the phase voltage at the rear end of the inductor is the same as the phase of the input current; if so, execute the following S303; if not, do not execute the following steps.

[0168] Optionally, the phase difference angle between the phase voltage at the rear end of the inductor and the input current can be obtained; when the phase difference angle is 0, the phase of the phase voltage at the rear end of the inductor is the same as the phase of the input current; when the phase difference angle is 90°, the phase of the phase voltage at the rear end of the inductor is different from the phase of the input current.

[0169] S303, obtaining a first mapping relationship based on the phase voltage, input power and input current at the rear end of the inductor.

[0170] Optionally, the first mapping relationship is an expression related to the phase voltage, input power and input current at the rear end of the inductor.

[0171] S304, when the area surrounded by the line voltage at the rear end of the inductor is equal to twice the area surrounded by the bus voltage, generate a third mapping relationship based on the average value of the effective value of the line voltage at the rear end of the inductor and the bus voltage.

[0172] Optionally, the third mapping relationship is an expression related to the average value of the effective value of the line voltage at the rear end of the inductor and the bus voltage.

[0173] S305, obtaining a phase voltage effective value based on an average value of the line voltage effective value at the rear end of the inductor.

[0174] Alternatively, since the line voltage is the phase voltage multiplied by (i.e. 1.732), so based on the average value of the effective value of the line voltage at the rear end of the inductor, the effective value of the phase voltage can be obtained.

[0175] S306, obtaining a second mapping relationship based on the third mapping relationship and the phase voltage effective value.

[0176] Optionally, the second mapping relationship is obtained by performing derivation calculation based on the third mapping relationship and the effective value of the phase voltage.

[0177] S307: Obtain a target mapping relationship based on the first mapping relationship and the second mapping relationship.

[0178] Optionally, a derivation calculation is performed based on the first mapping relationship and the second mapping relationship to obtain a target mapping relationship.

[0179] S308, obtaining the current input power and the current bus voltage of the three-phase AC inverter.

[0180] Optionally, the current input power may be obtained based on the load power and the loss power in the three-phase AC inverter.

[0181] Optionally, the current bus voltage may be acquired based on a corresponding voltage-dividing sampling circuit.

[0182] S309, based on the current input power, the current bus voltage and the target mapping relationship, obtain the current input current effective value of the three-phase AC inverter.

[0183] For the above S301 to S309, reference may be made to the detailed description of S201 to S205 in the above embodiment, which will not be described in detail in the embodiment of the present application.

[0184] In the embodiment of the present application, since a target mapping relationship indicating a corresponding relationship between a first target parameter and an input current can be obtained based on the input current, bus voltage, and phase voltage at the rear end of the inductor of the three-phase AC inverter, and the first target parameter includes the input power of the three-phase AC inverter and the bus voltage, when the current input power and the current bus voltage of the three-phase AC inverter are obtained, the current input current effective value of the three-phase AC inverter can be accurately calculated based on the current input power and the current bus voltage and the target mapping relationship, thereby eliminating the need to add a current transformer on the input side of the three-phase AC inverter to obtain an input current sensor, or eliminating the need to add a sampling circuit to obtain an input current sensor based on the collected V ac And load power to calculate the input current I ac , the accurate input current can be calculated directly through the derived corresponding relationship; therefore, the above scheme can obtain the input current of the three-phase AC inverter without increasing the hardware cost.

[0185] Combination of the above Figures 1 to 8 The calculation method of the input current of the three-phase AC inverter provided in the embodiment of the present application is described in detail; Fig. 9 and Fig.10 The device embodiments of the present application are described in detail. It should be understood that the device in the embodiments of the present application can execute the various methods of the aforementioned embodiments of the present application, that is, the specific working processes of the following various products can refer to the corresponding processes in the aforementioned method embodiments.

[0186] Fig. 9 It is a structural schematic diagram of a three-phase AC inverter input current calculation device provided in an embodiment of the present application.

[0187] For example, Fig. 9 As shown, the computing device 400 includes:

[0188] The first generating module 410 is used to obtain a first mapping relationship based on the effective value of the phase voltage, the input power and the input current of the inductor rear end of the three-phase AC inverter; wherein the inductor rear end is the output end of the inverter;

[0189] The second generating module 420 is used to obtain a second mapping relationship based on the effective value of the phase voltage and the bus voltage; wherein the bus voltage is the voltage across the DC bus capacitor in the three-phase AC inverter;

[0190] A first determination module 430 is used to determine a target mapping relationship based on the first mapping relationship and the second mapping relationship; wherein the target mapping relationship is used to represent a mapping relationship between a first target parameter and the input current; and the first target parameter includes the bus voltage and the input power;

[0191] A first acquisition module 440 is used to acquire the current input power and the current bus voltage of the three-phase AC inverter;

[0192] The second determination module 450 is configured to determine a current input current effective value of the three-phase AC inverter based on the current input power, the current bus voltage and the target mapping relationship.

[0193] In a possible implementation, the first acquisition module 440 is further used to: acquire the phase of the phase voltage at the rear end of the inductor and the phase of the input current;

[0194] The first generating module 410 is specifically used to: determine whether the phase of the phase voltage is the same as the phase of the input current; when the phase of the phase voltage is the same as the phase of the input current, obtain the first mapping relationship based on the effective value of the phase voltage at the rear end of the inductor, the input power and the input current.

[0195] In a possible implementation, the second generating module 420 is specifically configured to: When the third mapping relationship is generated based on the average value of the effective value of the line voltage at the rear end of the inductor and the bus voltage, the third mapping relationship is used to indicate the corresponding relationship between the average value of the effective value of the line voltage at the rear end of the inductor and the bus voltage; the phase voltage effective value is obtained based on the average value of the effective value of the line voltage at the rear end of the inductor; the second mapping relationship is obtained based on the third mapping relationship and the phase voltage effective value; wherein, V L12-inv 、V L23-inv and V L31-inv is the line voltage at the rear end of the inductor, T is the period, and t is the time; the average value of the effective value of the line voltage is V L12-inv 、V L23-inv and V L31-inv The mean of .

[0196] In a possible implementation, the first determination module 430 is specifically configured to: obtain a target formula based on the first mapping relationship and the second mapping relationship;

[0197] Based on the target formula, obtaining the target mapping relationship;

[0198] Wherein, the target formula is I ac = P / ( V dc );I ac represents the input current of the three-phase AC inverter, P represents the input power of the three-phase AC inverter, V dc Indicates the bus voltage of the three-phase AC inverter.

[0199] In a possible implementation, the first generation module 410 is specifically used to: obtain a first formula based on the effective value of the phase voltage at the inductor rear end of the three-phase AC inverter, the input power and the input current; wherein the first formula is used to represent the first mapping relationship;

[0200] The first formula is I ac = P / (3 V LN-inv ); where I ac represents the input current of the three-phase AC inverter, P represents the input power of the three-phase AC inverter, V LN-inv It represents the effective value of the phase voltage at the rear end of the inductor.

[0201] In a possible implementation, the second generating module 420 is specifically used to: obtain a second formula based on the phase voltage effective value and the bus voltage; wherein the second formula is used to represent the second mapping relationship;

[0202] The second formula is V LN-inv = / 3 V dc ; Among them, V LN-inv Represents the effective value of the phase voltage at the rear end of the inductor, V dc Indicates the bus voltage of the three-phase AC inverter.

[0203] In a possible implementation, the second generating module 420 is specifically used to: obtain a third formula based on the average value of the effective value of the line voltage at the rear end of the inductor and the bus voltage; wherein the third formula is used to represent the third mapping relationship;

[0204] The third formula is V inv-avg = V dc ; Among them, V inv-avg Represents the average value of the effective value of the line voltage at the rear end of the inductor, V dc Indicates the bus voltage of the three-phase AC inverter.

[0205] Fig.10 It is a structural schematic diagram of an air conditioner provided in an embodiment of the present application.

[0206] For example, Fig.10 As shown, the air conditioner 500 includes: a memory 501 and a processor 502, wherein the memory 501 stores an executable program code 5011, and the processor 502 is used to call and execute the executable program code 5011 to perform a method for calculating the input current of a three-phase AC inverter.

[0207] In addition, an embodiment of the present application also protects a device, which may include a memory and a processor, wherein the memory stores an executable program code, and the processor is used to call and execute the executable program code to execute a method for calculating the input current of a three-phase AC inverter provided in an embodiment of the present application.

[0208] In this embodiment, the functional modules of the device can be divided according to the above method example. For example, each functional module can be corresponded, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware. It should be noted that the division of modules in this embodiment is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0209] In the case of dividing each functional module according to each function, the device may further include a first generating module, a second generating module, a first determining module, a first acquiring module, a second determining module, etc. It should be noted that all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module, which will not be repeated here.

[0210] It should be understood that the device provided in this embodiment is used to execute the above-mentioned method for calculating the input current of a three-phase AC inverter, and thus can achieve the same effect as the above-mentioned implementation method.

[0211] In the case of an integrated unit, the device may include a processing module and a storage module. When the device is applied to an air conditioner, the processing module may be used to control and manage the air conditioner. The storage module may be used to support the air conditioner to execute related program codes, etc.

[0212] The processing module may be a processor or a controller, which may implement or execute various exemplary logic blocks, modules and circuits shown in combination with the contents disclosed in this application. The processor may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, etc. The storage module may be a memory.

[0213] In addition, the device provided in the embodiments of the present application may specifically be a chip, a component or a module, and the chip may include a connected processor and a memory; wherein the memory is used to store instructions, and when the processor calls and executes the instructions, the chip can execute a method for calculating the input current of a three-phase AC inverter provided in the above embodiment.

[0214] This embodiment also provides a computer-readable storage medium, in which a computer program code is stored. When the computer program code is executed on a computer, the computer executes the above-mentioned related method steps to implement a method for calculating the input current of a three-phase AC inverter provided in the above embodiment.

[0215] This embodiment further provides a computer program product. When the computer program product is run on a computer, the computer is caused to execute the above-mentioned related steps to implement a method for calculating the input current of a three-phase AC inverter provided in the above embodiment.

[0216] Among them, the device, computer-readable storage medium, computer program product or chip provided in this embodiment is used to execute the corresponding method provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding method provided above, and will not be repeated here.

[0217] Through the description of the above implementation methods, technical personnel in the relevant field can understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0218] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of modules or units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0219] The above contents are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for calculating the input current of a three-phase AC inverter, characterized in that: The three-phase AC inverter includes: an AC power supply module, a reactance module, a rectifier module, a DC bus capacitor and an inverter module. The method includes: A first mapping relationship is obtained based on the effective value of the phase voltage, input power and input current of the inductor rear end of the three-phase AC inverter; wherein the inductor rear end is the output end of the inverter; Based on the phase voltage effective value and the bus voltage, a second mapping relationship is obtained; wherein the bus voltage is the voltage across the DC bus capacitor in the three-phase AC inverter; Based on the first mapping relationship and the second mapping relationship, a target mapping relationship is determined; wherein the target mapping relationship is used to represent a mapping relationship between a first target parameter and the input current; the first target parameter includes the bus voltage and the input power; Obtaining the current input power and current bus voltage of the three-phase AC inverter; Based on the current input power, the current bus voltage and the target mapping relationship, a current input current effective value of the three-phase AC inverter is determined.

2. The method according to claim 1, characterized in that The method further comprises: Acquire the phase of the phase voltage at the rear end of the inductor and the phase of the input current; Determining whether the phase of the phase voltage is the same as the phase of the input current; The first mapping relationship is obtained based on the effective value of the phase voltage at the inductor rear end of the three-phase AC inverter, the input power and the input current, including: When the phase of the phase voltage is the same as the phase of the input current, the first mapping relationship is obtained based on the effective value of the phase voltage at the rear end of the inductor, the input power and the input current.

3. The method according to claim 1, characterized in that The obtaining of a second mapping relationship based on the phase voltage effective value and the bus voltage includes: exist When the third mapping relationship is generated based on the average value of the effective value of the line voltage at the rear end of the inductor and the bus voltage, the third mapping relationship is used to indicate the corresponding relationship between the average value of the effective value of the line voltage at the rear end of the inductor and the bus voltage. L12-inv 、V L23-inv and V L31-inv is the line voltage at the rear end of the inductor, T is the period, t is the time; V dc represents the bus voltage of the three-phase AC inverter, and the average value of the effective value of the line voltage is V L12-inv 、V L23-inv and V L31-inv The mean of Obtaining the phase voltage effective value based on the average value of the line voltage effective value at the rear end of the inductor; The second mapping relationship is obtained based on the third mapping relationship and the phase voltage effective value.

4. The method according to claim 1, characterized in that: The determining a target mapping relationship based on the first mapping relationship and the second mapping relationship includes: Based on the first mapping relationship and the second mapping relationship, obtaining a target formula; Based on the target formula, obtaining the target mapping relationship; Wherein, the target formula is I ac = P / ( V dc );I ac represents the input current of the three-phase AC inverter, P represents the input power of the three-phase AC inverter, V dc Indicates the bus voltage of the three-phase AC inverter.

5. The method according to claim 2, characterized in that: The obtaining of the first mapping relationship based on the effective value of the phase voltage at the rear end of the inductor, the input power and the input current includes: A first formula is obtained based on the effective value of the phase voltage at the rear end of the inductor, the input power and the input current; wherein the first formula is used to represent the first mapping relationship; The first formula is I ac = P / (3 V LN-inv ); where I ac represents the input current of the three-phase AC inverter, P represents the input power of the three-phase AC inverter, V LN-inv It represents the effective value of the phase voltage at the rear end of the inductor.

6. The method according to claim 1, characterized in that The obtaining of a second mapping relationship based on the phase voltage effective value and the bus voltage includes: A second formula is obtained based on the phase voltage effective value and the bus voltage; wherein the second formula is used to represent the second mapping relationship; The second formula is V LN-inv = / 3 V dc ; Among them, V LN-inv Represents the effective value of the phase voltage at the rear end of the inductor, V dc Indicates the bus voltage of the three-phase AC inverter.

7. The method according to claim 3, characterized in that The generating a third mapping relationship based on the average value of the effective value of the line voltage at the rear end of the inductor and the bus voltage comprises: A third formula is obtained based on the average value of the effective value of the line voltage at the rear end of the inductor and the bus voltage; wherein the third formula is used to represent the third mapping relationship; The third formula is V inv-avg = V dc ; Among them, V inv-avg Represents the average value of the effective value of the line voltage at the rear end of the inductor, V dc Indicates the bus voltage of the three-phase AC inverter.

8. A device for calculating input current of a three-phase AC inverter, characterized in that: The three-phase AC inverter includes: an AC power supply module, a reactor module, a rectifier module, a DC bus capacitor and an inverter module. The device includes: A first generating module, configured to obtain a first mapping relationship based on the effective value of the phase voltage, the input power and the input current of the inductor rear end of the three-phase AC inverter; wherein the inductor rear end is the output end of the inverter; A second generating module, configured to obtain a second mapping relationship based on the effective value of the phase voltage and the bus voltage; wherein the bus voltage is the voltage across the DC bus capacitor in the three-phase AC inverter; A first determination module, configured to determine a target mapping relationship based on the first mapping relationship and the second mapping relationship; wherein the target mapping relationship is used to represent a mapping relationship between a first target parameter and the input current; and the first target parameter includes the bus voltage and the input power; A first acquisition module, used to acquire the current input power and the current bus voltage of the three-phase AC inverter; The second determination module is used to determine the current input current effective value of the three-phase AC inverter based on the current input power, the current bus voltage and the target mapping relationship.

9. An air conditioner, characterized in that: The air conditioner comprises: A memory for storing executable program codes; A processor, configured to call and run the executable program code from the memory, so that the air conditioner executes the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed, the method according to any one of claims 1 to 7 is implemented.

11. A computer program product, characterized in that The invention comprises a computer program, which implements the method according to any one of claims 1 to 7 when being executed by a processor.

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