Current sampling method, apparatus and inverter device

Abstract

The application provides a current sampling method, device and inverter equipment. The method comprises the following steps: when a first carrier point of a carrier of a PWM unit corresponding to a target load equipment in a target PWM period is detected, sampling a load current of the target load equipment according to a time of the first carrier point to obtain a first current sampling value; wherein the first carrier point is any carrier point of the carrier in a first half period of the target PWM period; when a second carrier point in the target PWM period is detected, sampling the load current according to a time of the second carrier point to obtain a second current sampling value; wherein the second carrier point is a carrier point which is away from the first carrier point by half of the target PWM period; and determining an average value of the first current sampling value and the second current sampling value as a sampling value of the load current. The application can eliminate the influence of switching ripple on current sampling and improve the accuracy of current sampling.

Description

Technical Field

[0001] This invention relates to the field of electrical signal sampling technology, and in particular to a current sampling method, apparatus, and inverter equipment. Background Technology

[0002] In PWM (Pulse Width Modulation) control, the output waveform of the bridge circuit is a high-frequency square wave. To achieve continuous output waveform, a filter circuit is required. However, due to cost and size constraints, the available filter circuits are limited and often lack sufficient filtering capability. This results in the inability to completely eliminate interference signals at the switching level, leading to high-frequency components, such as switching ripple, in the output voltage or current at the load end. These high-frequency components significantly reduce the accuracy of current sampling, which in turn reduces the effectiveness of PWM control. Summary of the Invention

[0003] This invention provides a current sampling method, apparatus, and inverter equipment to solve the problem of low accuracy of current sampling caused by switching ripple in the prior art.

[0004] In a first aspect, embodiments of the present invention provide a current sampling method, including:

[0005] When the carrier of the PWM unit corresponding to the target load device is detected to be at the first carrier point within the target PWM cycle, the load current of the target load device is sampled according to the time of the first carrier point to obtain the first current sample value; wherein, the first carrier point is any carrier point in the first half of the target PWM cycle;

[0006] When the second carrier point within the target PWM cycle is detected, the load current is sampled according to the time of the second carrier point to obtain the second current sample value; wherein, the second carrier point is the carrier point that is half a target PWM cycle away from the first carrier point;

[0007] The average of the first current sample value and the second current sample value is determined as the sample value of the load current.

[0008] In one possible implementation, the load current of the target load device is sampled based on the time of the first carrier point to obtain a first current sample value, including:

[0009] The current value in the load current corresponding to the time of the first carrier point is sampled as the first current sample value;

[0010] The load current of the target load device is sampled based on the time of the second carrier point to obtain the second current sample value, including:

[0011] The current value in the load current corresponding to the time of the second carrier point is sampled as the second current sample value.

[0012] In one possible implementation, the load current of the target load device is sampled based on the time of the first carrier point to obtain a first current sample value, including:

[0013] The current value in the load current corresponding to the first moment is sampled as the first current sample value; wherein, the first moment is the sum of the moment of the first carrier point and the preset lag time, and the preset lag time is the delay time of the load current relative to the carrier.

[0014] The load current of the target load device is sampled based on the time of the second carrier point to obtain the second current sample value, including:

[0015] The current value corresponding to the second moment in the load current is sampled as the second current sampling value; where the second moment is the sum of the moment of the second carrier point and the preset lag time.

[0016] In one possible implementation, the carrier wave is an isosceles triangular wave, with the first carrier point being the starting point of the isosceles triangular wave and the second carrier point being the highest point of the isosceles triangular wave.

[0017] In one possible implementation, the carrier wave is a right-angled triangular wave, the first carrier point is the starting point of the right-angled triangular wave, and the second carrier point is the midpoint between the starting point and the highest point of the right-angled triangular wave.

[0018] In one possible implementation, the target load is either a capacitive or inductive load.

[0019] Secondly, embodiments of the present invention provide a current sampling device, comprising:

[0020] The first sampling module is used to sample the load current of the target load device according to the time of the first carrier point when the carrier of the PWM unit corresponding to the target load device is detected to be at the first carrier point in the target PWM cycle, and obtain the first current sampling value; wherein, the first carrier point is any carrier point in the first half of the target PWM cycle;

[0021] The second sampling module is used to sample the load current according to the time of the second carrier point when the second carrier point is detected within the target PWM cycle, and obtain the second current sampling value; wherein, the second carrier point is the carrier point that is half a target PWM cycle away from the first carrier point;

[0022] The sampling value determination module is used to determine the average value of the first current sampling value and the second current sampling value as the sampling value of the load current.

[0023] In one possible implementation, the first sampling module is specifically used for:

[0024] The current value in the load current corresponding to the time of the first carrier point is sampled as the first current sample value;

[0025] The second sampling module is specifically used for:

[0026] The current value in the load current corresponding to the time of the second carrier point is sampled as the second current sample value.

[0027] In one possible implementation, the first sampling module is specifically used for:

[0028] The current value in the load current corresponding to the first moment is sampled as the first current sample value; wherein, the first moment is the sum of the moment of the first carrier point and the preset lag time, and the preset lag time is the delay time of the load current relative to the carrier.

[0029] The second sampling module is specifically used for:

[0030] The current value corresponding to the second moment in the load current is sampled as the second current sampling value; where the second moment is the sum of the moment of the second carrier point and the preset lag time.

[0031] In one possible implementation, the carrier wave is an isosceles triangular wave, with the first carrier point being the starting point of the isosceles triangular wave and the second carrier point being the highest point of the isosceles triangular wave.

[0032] In one possible implementation, the carrier wave is a right-angled triangular wave, the first carrier point is the starting point of the right-angled triangular wave, and the second carrier point is the midpoint between the starting point and the highest point of the right-angled triangular wave.

[0033] In one possible implementation, the target load is either a capacitive or inductive load.

[0034] Thirdly, embodiments of the present invention provide an inverter device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method described in the first aspect.

[0035] This invention provides a current sampling method, apparatus, and inverter device. When the carrier wave of the PWM unit corresponding to the target load device is detected at a first carrier point within the target PWM cycle, the load current of the target load device is sampled according to the time of the first carrier point to obtain a first current sample value. When a second carrier point within the target PWM cycle is detected, the load current is sampled according to the time of the second carrier point to obtain a second current sample value. Since the first and second carrier points are set to be half a target PWM cycle apart, when the average value of the first and second current sample values ​​is taken, the switching ripple in the first and second current sample values ​​can be exactly canceled out, thereby avoiding the influence of switching ripple on the accuracy of current sampling, greatly improving the accuracy of current sampling, and thus improving the control effect of PWM. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a flowchart of the steps of a current sampling method provided in an embodiment of the present invention;

[0038] Figure 2 This is a schematic diagram of a first carrier point and a second carrier point provided in an embodiment of the present invention;

[0039] Figure 3 This is a schematic diagram of another first carrier point and second carrier point provided in an embodiment of the present invention;

[0040] Figure 4 This is a schematic diagram of the structure of a current sampling device provided in an embodiment of the present invention;

[0041] Figure 5 This is a schematic diagram of an inverter device provided in an embodiment of the present invention. Detailed Implementation

[0042] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0043] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments will be described below in conjunction with the accompanying drawings.

[0044] As described in the background section, for devices limited by cost and size requirements, the available filter circuits are limited, typically consisting of low-cost, small-size conventional filter circuits. These circuits cannot provide adequate filtering capabilities, resulting in the inability to completely eliminate switching-level interference signals. This leads to the presence of high-frequency components such as switching ripple in the output voltage or current at the load end. These high-frequency components significantly reduce the accuracy of current sampling, which in turn reduces the control effect of PWM. This is especially true when the load is capacitive, as the low high-frequency impedance of capacitive loads makes the high-frequency components in the load current even more pronounced, further reducing the accuracy of current sampling.

[0045] Furthermore, existing current sampling methods themselves suffer from inaccurate sampling. Specifically, the common industry practice is to sample once within a PWM cycle, determining the current value corresponding to the midpoint of the load current within the PWM cycle as the sampled current value. However, this sampling method ignores the phase shift caused by the filtering circuit in the load circuit, and this phase shift cannot be accurately calculated. Therefore, when sampling based on the midpoint of the PWM cycle, the obtained sampled current value is not the actual current value corresponding to the midpoint of the PWM cycle, and thus the sampled current value is not the average value of the load current, resulting in inaccurate sampling. In addition, this current sampling method is also affected by switching ripple during sampling, further reducing its accuracy.

[0046] To address the problems of the prior art, embodiments of the present invention provide a current sampling method, apparatus, and inverter device. The current sampling method provided by the embodiments of the present invention is described below.

[0047] The entity executing the current sampling method can be a current sampling device, such as an inverter including a sampling circuit, and this embodiment of the invention does not specifically limit it.

[0048] See Figure 1 The diagram illustrates the implementation flowchart of the current sampling method provided in this embodiment of the invention, including the following steps:

[0049] Step 110: When the carrier of the PWM unit corresponding to the target load device is detected to be at the first carrier point in the target PWM cycle, the load current of the target load device is sampled according to the time of the first carrier point to obtain the first current sample value; wherein, the first carrier point can be any carrier point in the first half of the target PWM cycle.

[0050] In some embodiments, the target load device can be any load device employing an inverter, such as a capacitive or inductive load. The target PWM period can be any PWM period, and the carrier wave can be an isosceles triangular wave or a right-angled triangular wave.

[0051] Optionally, the process of sampling the load current of the target load device according to the time of the first carrier point in step 110 to obtain the first current sample value can be as follows: sample the current value in the load current corresponding to the time of the first carrier point as the first current sample value.

[0052] Specifically, when the first carrier point is detected, the detection time, i.e., the time of the first carrier point, can be recorded. Then, sampling can be performed according to this detection time, and the current value in the load current corresponding to this detection time can be sampled as the first current sample value.

[0053] Optionally, considering that some load currents are delayed relative to the carrier, in such cases, the process of sampling the load current of the target load device according to the time of the first carrier point to obtain the first current sample value in step 110 can be as follows: sample the current value in the load current corresponding to the first time point as the first current sample value; wherein, the first time point is the sum of the time of the first carrier point and the preset lag time, and the preset lag time is the delay time of the load current relative to the carrier.

[0054] Specifically, when the first carrier point is detected, the detection time, i.e., the time of the first carrier point, can be recorded. Then, sampling can be performed according to the sum of the detection time and the preset lag time, i.e., the first time, and the current value in the load current corresponding to the first time can be sampled as the first current sampling value.

[0055] It should be noted that the delay of the load current relative to the carrier wave can be accurately calculated, typically being one PWM cycle. Correspondingly, a preset hysteresis duration can be set to one PWM cycle. Alternatively, this delay can be detected beforehand, and the detected delay duration can be used as the preset hysteresis duration.

[0056] Step 120: When the second carrier point within the target PWM cycle is detected, the load current is sampled according to the time of the second carrier point to obtain the second current sample value; wherein, the second carrier point is the carrier point that is half a target PWM cycle away from the first carrier point.

[0057] In some embodiments, considering the limited accuracy of some PWM counters, an easily detectable point can be selected as the first carrier point, such as the start point or midpoint of the carrier, based on the accuracy of the PWM counter.

[0058] In some embodiments, when an isosceles triangular wave is used as the carrier wave, the first carrier point can be set as the starting point of the isosceles triangular wave. Correspondingly, the point half a target PWM cycle away from the first carrier point is exactly the highest point of the isosceles triangular wave, i.e., the second carrier point. For example... Figure 2 The diagram shows a schematic of a first carrier point and a second carrier point. Figure 2 In the diagram, number 21 is the first carrier point, and number 22 is the second carrier point.

[0059] It should be noted that other carrier points that are easy to detect can also be selected, such as the carrier point in the isosceles triangular wave corresponding to one-quarter of the target PWM period, or the carrier point in the isosceles triangular wave corresponding to one-fifth of the target PWM period, etc. The embodiments of the present invention do not specifically limit them.

[0060] In some embodiments, when using a right-angled triangular wave as the carrier wave, such as a right-angled triangular wave whose amplitude increases sequentially from left to right, the first carrier point can be set as the starting point of the right-angled triangular wave, and the point half a target PWM cycle away from the first carrier point is exactly the midpoint between the starting point and the highest point of the right-angled triangular wave. Correspondingly, for a right-angled triangular wave whose amplitude decreases sequentially from left to right, the first carrier point can be set as the starting point of the right-angled triangular wave, and the point half a target PWM cycle away from the first carrier point is exactly the midpoint between the starting point and the lowest point of the right-angled triangular wave. Figure 3 The diagram shows a schematic of a first carrier point and a second carrier point. Figure 3 In the diagram, number 31 is the first carrier point, and number 32 is the second carrier point.

[0061] It should be noted that other carrier points that are easy to detect can also be selected, such as carrier points in a right-angled triangular wave that correspond to one-quarter of the target PWM period, carrier points in a right-angled triangular wave that correspond to one-fifth of the target PWM period, etc. The embodiments of the present invention do not specifically limit them.

[0062] In some embodiments, similar to the processing of the first current sampling value described above, when the second carrier point is detected, the detection time, i.e., the time of the second carrier point, can be recorded. Then, sampling can be performed according to the detection time, and the current value in the load current corresponding to the detection time can be sampled as the second current sampling value. Furthermore, if there is a delay between the load current and the carrier, sampling can be performed according to the time of the sum of the detection time of the second carrier point and a preset lag time, i.e., the second time, and the current value in the load current corresponding to the second time can be sampled as the second current sampling value.

[0063] Step 130: The average value of the first current sample value and the second current sample value is determined as the sample value of the load current.

[0064] After obtaining the first current sample value and the second current sample value, the average value of the first current sample value and the second current sample value is calculated and determined as the sample value of the load current of the target load device.

[0065] It should be noted that when averaging the first and second current sample values ​​obtained using the above sampling method, the switching ripple in the first and second current sample values ​​can be exactly canceled out. The process of canceling the switching ripple is described in detail below.

[0066] Switching ripple can be represented in the following form:

[0067]

[0068] Accordingly, the switching ripple component in the first current sample value can be expressed as:

[0069]

[0070] The switching ripple component in the second current sample value can be expressed as:

[0071]

[0072] Based on the above representation, when the first current sample value and the second current sample value are added together and averaged, the following result can be obtained for the switching ripple component:

[0073]

[0074] Therefore, the switching ripples in the first and second current sample values ​​cancel each other out. Thus, the sampling method provided by this embodiment of the invention can cancel out the switching ripples, avoiding their impact on the accuracy of current sampling, thereby greatly improving the accuracy of current sampling and consequently enhancing the control effect of the PWM.

[0075] It should be noted that the sampling method provided in this embodiment of the invention does not need to consider the phase shift caused by the filter circuit in the load circuit. This is because, during sampling, this embodiment does not need to precisely find the current value corresponding to the midpoint of the load current within the PWM cycle. This embodiment only needs to sample twice within one PWM cycle, with an interval of half a cycle between the two samplings, and then average the two sampling results to obtain the average value of the load current. In other words, existing sampling methods cannot accurately find the midpoint of the load current within the PWM cycle, while this embodiment of the invention, from another perspective, bypasses the obstacle of inaccurate midpoint finding, not only sampling the average value of the load current but also canceling out switching ripple.

[0076] It should be reiterated that, because the current sampling method provided in this embodiment of the invention can cancel the switching ripple in the sampling results, it can still achieve extremely high sampling accuracy for devices limited by cost and size requirements, even if the filtering effect of their filtering circuit is average or poor. Furthermore, the current sampling method provided in this embodiment of the invention only requires two samples per PWM cycle, which does not place high demands on chip processing resources and does not lengthen interrupt time, thus offering the advantage of low implementation difficulty.

[0077] In this embodiment of the invention, a current sampling method utilizing carrier points is provided. Specifically, when the carrier of the PWM unit corresponding to the target load device is detected at a first carrier point within the target PWM cycle, the load current of the target load device is sampled based on the time of the first carrier point to obtain a first current sample value. When a second carrier point within the target PWM cycle is detected, the load current is sampled based on the time of the second carrier point to obtain a second current sample value. Since the first and second carrier points are set to be half a target PWM cycle apart, when the average of the first and second current sample values ​​is taken, the switching ripple in the first and second current sample values ​​can be precisely canceled out. This avoids the influence of switching ripple on the accuracy of current sampling, greatly improving the accuracy of current sampling and thus improving the control effect of PWM.

[0078] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0079] The following are device embodiments of the present invention. For details not described in detail, please refer to the corresponding method embodiments described above.

[0080] Figure 4 A schematic diagram of the current sampling device provided in an embodiment of the present invention is shown. For ease of explanation, only the parts related to the embodiment of the present invention are shown, and are described in detail below:

[0081] like Figure 4 As shown, the current sampling device includes:

[0082] The first sampling module 410 is used to sample the load current of the target load device according to the time of the first carrier point when the carrier of the PWM unit corresponding to the target load device is detected to be at the first carrier point in the target PWM cycle, and obtain the first current sampling value; wherein, the first carrier point is any carrier point in the first half of the target PWM cycle;

[0083] The second sampling module 420 is used to sample the load current according to the time of the second carrier point when the second carrier point within the target PWM cycle is detected, and obtain the second current sampling value; wherein, the second carrier point is the carrier point that is half a target PWM cycle away from the first carrier point;

[0084] The sampling value determination module 430 is used to determine the average value of the first current sampling value and the second current sampling value as the sampling value of the load current.

[0085] In one possible implementation, the first sampling module is specifically used for:

[0086] The current value in the load current corresponding to the time of the first carrier point is sampled as the first current sample value;

[0087] Correspondingly, the second sampling module is specifically used for:

[0088] The current value in the load current corresponding to the time of the second carrier point is sampled as the second current sample value.

[0089] In one possible implementation, the first sampling module is specifically used for:

[0090] The current value in the load current corresponding to the first moment is sampled as the first current sample value; wherein, the first moment is the sum of the moment of the first carrier point and the preset lag time, and the preset lag time is the delay time of the load current relative to the carrier.

[0091] Correspondingly, the second sampling module is specifically used for:

[0092] The current value corresponding to the second moment in the load current is sampled as the second current sampling value; where the second moment is the sum of the moment of the second carrier point and the preset lag time.

[0093] In one possible implementation, the carrier wave is an isosceles triangular wave, with the first carrier point being the starting point of the isosceles triangular wave and the second carrier point being the highest point of the isosceles triangular wave.

[0094] In one possible implementation, the carrier wave is a right-angled triangular wave, the first carrier point is the starting point of the right-angled triangular wave, and the second carrier point is the midpoint between the starting point and the highest point of the right-angled triangular wave.

[0095] In one possible implementation, the target load is either a capacitive or inductive load.

[0096] In this embodiment of the invention, a current sampling method utilizing carrier points is provided. Specifically, when the carrier of the PWM unit corresponding to the target load device is detected at a first carrier point within the target PWM cycle, the load current of the target load device is sampled based on the time of the first carrier point to obtain a first current sample value. When a second carrier point within the target PWM cycle is detected, the load current is sampled based on the time of the second carrier point to obtain a second current sample value. Since the first and second carrier points are set to be half a target PWM cycle apart, when the average of the first and second current sample values ​​is taken, the switching ripple in the first and second current sample values ​​can be precisely canceled out. This avoids the influence of switching ripple on the accuracy of current sampling, greatly improving the accuracy of current sampling and thus improving the control effect of PWM.

[0097] Figure 5 This is a schematic diagram of the inverter device 5 provided in an embodiment of the present invention. Figure 5 As shown, the inverter device 5 in this embodiment includes: a processor 50, a memory 51, and a computer program 52 stored in the memory 51 and executable on the processor 50. When the processor 50 executes the computer program 52, it implements the steps in the various current sampling method embodiments described above, for example... Figure 1 Steps 110 to 150 are shown. Alternatively, when the processor 50 executes the computer program 52, it implements the functions of each module in the above-described device embodiments, for example... Figure 4 The functions of modules 410 to 450 are shown.

[0098] For example, the computer program 52 can be divided into one or more modules, which are stored in the memory 51 and executed by the processor 50 to complete the present invention. The one or more modules can be a series of computer program instruction segments capable of performing specific functions, which describe the execution process of the computer program 52 in the inverter device 5. For example, the computer program 52 can be divided into... Figure 4 Modules 410 to 450 are shown.

[0099] The inverter device 5 may include, but is not limited to, a processor 50 and a memory 51. Those skilled in the art will understand that... Figure 5 This is merely an example of inverter device 5 and does not constitute a limitation on inverter device 5. It may include more or fewer components than shown, or combine certain components, or different components. For example, the inverter device may also include a power module, an inverter module, a rectifier module, etc.

[0100] The processor 50 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0101] The memory 51 can be an internal storage unit of the inverter device 5, such as a hard disk or memory of the inverter device 5. The memory 51 can also be an external storage device of the inverter device 5, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the inverter device 5. Furthermore, the memory 51 can include both internal and external storage units of the inverter device 5. The memory 51 is used to store the computer program and other programs and data required by the inverter device. The memory 51 can also be used to temporarily store data that has been output or will be output.

[0102] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0103] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0104] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0105] In the embodiments provided by this invention, it should be understood that the disclosed apparatus / terminal devices and methods can be implemented in other ways. For example, the apparatus / terminal device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0106] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0107] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0108] If the integrated module is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various current sampling method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0109] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A current sampling method, characterized in that, The method, applied to an inverter device containing a filter circuit and exhibiting high-frequency switching ripple components, includes: When the carrier of the PWM unit corresponding to the target load device is detected to be at the first carrier point within the target PWM cycle, the load current of the target load device is sampled according to the time of the first carrier point to obtain a first current sampling value; wherein, the first carrier point is any carrier point of the carrier in the first half of the target PWM cycle; When a second carrier point within the target PWM cycle is detected, the load current is sampled according to the time of the second carrier point to obtain a second current sample value; wherein, the second carrier point is a carrier point that is half a target PWM cycle away from the first carrier point; The average value of the first current sample value and the second current sample value is determined as the sample value of the load current; wherein, when taking the average value, the switching ripple in the first current sample value and the second current sample value cancel each other out.

2. The current sampling method according to claim 1, characterized in that, The step of sampling the load current of the target load device according to the time of the first carrier point to obtain a first current sample value includes: The current value in the load current corresponding to the time of the first carrier point is sampled as the first current sample value; The step of sampling the load current of the target load device according to the time of the second carrier point to obtain the second current sample value includes: The current value in the load current corresponding to the time of the second carrier point is sampled as the second current sample value.

3. The current sampling method according to claim 1, characterized in that, The step of sampling the load current of the target load device according to the time of the first carrier point to obtain a first current sample value includes: The current value corresponding to the first moment in the load current is sampled as the first current sample value; wherein, the first moment is the sum of the moment of the first carrier point and the preset lag time, and the preset lag time is the delay time of the load current relative to the carrier. The step of sampling the load current of the target load device according to the time of the second carrier point to obtain the second current sample value includes: The current value corresponding to the second time point in the load current is sampled as the second current sample value; wherein, the second time point is the sum of the time of the second carrier point and the preset lag time.

4. The current sampling method according to any one of claims 1 to 3, characterized in that, The carrier wave is an isosceles triangular wave, the first carrier point is the starting point of the isosceles triangular wave, and the second carrier point is the highest point of the isosceles triangular wave.

5. The current sampling method according to any one of claims 1 to 3, characterized in that, The carrier wave is a right-angled triangular wave, the first carrier point is the starting point of the right-angled triangular wave, and the second carrier point is the midpoint between the starting point and the highest point of the right-angled triangular wave.

6. The current sampling method according to any one of claims 1 to 3, characterized in that, The target load is either a capacitive or inductive load.

7. A current sampling device, characterized in that, An inverter device that includes a filter circuit and has a high-frequency switching ripple component is used in an inverter equipment, the device comprising: The first sampling module is used to sample the load current of the target load device according to the time of the first carrier point when the carrier of the PWM unit corresponding to the target load device is detected to be at the first carrier point in the target PWM cycle, and obtain a first current sampling value; wherein, the first carrier point is any carrier point of the carrier in the first half of the target PWM cycle; The second sampling module is used to sample the load current according to the time of the second carrier point when a second carrier point is detected within the target PWM cycle, and obtain a second current sampling value; wherein, the second carrier point is a carrier point that is half a target PWM cycle away from the first carrier point; The sampling value determination module is used to determine the average value of the first current sampling value and the second current sampling value as the sampling value of the load current; wherein, when taking the average value, the switching ripple in the first current sampling value and the second current sampling value cancel each other out.

8. The current sampling device according to claim 7, characterized in that, The first sampling module is specifically used for: The current value in the load current corresponding to the time of the first carrier point is sampled as the first current sample value; The second sampling module is specifically used for: The current value in the load current corresponding to the time of the second carrier point is sampled as the second current sample value.

9. The current sampling device according to claim 7, characterized in that, The first sampling module is specifically used for: The current value corresponding to the first moment in the load current is sampled as the first current sample value; wherein, the first moment is the sum of the moment of the first carrier point and the preset lag time, and the preset lag time is the delay time of the load current relative to the carrier. The second sampling module is specifically used for: The current value corresponding to the second time point in the load current is sampled as the second current sample value; wherein, the second time point is the sum of the time of the second carrier point and the preset lag time.

10. An inverter device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method as described in any one of claims 1 to 6.

Images