Method, device and equipment for correcting current waveform of variable frequency equipment

Abstract

The present application relates to the technical field of intelligent devices, and discloses a method, device and equipment for current waveform correction of a frequency conversion device. The method includes: obtaining the DC bus voltage value of the frequency conversion device in the current period; performing single-voltage power factor PFC control according to the DC bus voltage value and the average value of the AC input current of the frequency conversion device in the current period to obtain the output value of the proportional-integral PI controller in the current period; performing differential compensation processing on the output value of the proportional-integral PI controller in the current period to obtain the duty ratio of the output in the current period, wherein the duty ratio differential compensation algorithm gain in the differential compensation processing is determined according to the DC bus voltage value and the voltage vector value required by the subsequent load; and performing PWM correction of the AC input current of the frequency conversion device in the current period according to the duty ratio of the output in the current period. In this way, the PFC harmonic suppression effect is improved.

Description

Technical Field

[0001] The present application relates to the technical field of intelligent terminals, for example, to a method, device, and equipment for correcting a current waveform of a variable-frequency device. Background Art

[0002] Variable-frequency devices, such as variable-frequency air conditioners, variable-frequency refrigerators, etc., have been increasingly and widely used. Generally, the input alternating current of a variable-frequency device can be corrected in waveform by a power factor correction (PFC) circuit combined with a software algorithm, so that the alternating current input waveform tracks the alternating current input voltage, thereby reducing current harmonics, and thus meeting the requirements of electrical safety and certification.

[0003] Currently, the PFC circuit can use a power factor correction scheme with a single voltage loop control strategy. Its advantages are that the cost can be reduced because the alternating current input voltage does not need to be sampled in hardware; the algorithm is simple and easy to implement because the current loop control is not required in software. At the same time, in order to further reduce the number of operations of power switching devices to reduce system power consumption, the single voltage loop scheme also adopts a DC bus voltage follow-up strategy, that is, in the light load and low frequency stage, when a high DC bus voltage is not required, a partial PFC operating mode is adopted instead of a full-wave PFC operating mode. This causes the output of the voltage loop PI control to saturate in the low frequency and light load stage. At the same time, since there is no current loop in the system, the current waveform cannot be directly controlled, resulting in a sawtooth oscillation of the alternating current under light load; on the other hand, if the output duty ratio deviation or distortion is caused by alternating current sampling interference or calculation deviation, the duty ratio distortion will inevitably lead to the distortion of the output alternating current. And due to the lack of closed-loop feedback control of the alternating current, when the distorted alternating current is used to calculate the next output duty ratio, it will further lead to the duty ratio distortion. In this way, a small sampling interference or calculation deviation will be amplified into a larger current distortion and distortion, thus affecting the PFC harmonic suppression effect and the system operation reliability.

[0004] In order to suppress the sawtooth oscillation and distortion of the alternating current under the single voltage loop control strategy, the current solutions may include: the follow-up of the DC voltage and the alternating current sampling point, and a special sawtooth pulse width modulation (PWM) control mode that can realize the immediate output of the new duty ratio value in the current cycle. However, the sampling point follow-up strategy is generally complex in design and difficult to achieve an optimal design in the full power range; in addition, the special PWM control strategy depends on the special hardware function peripherals of the MCU chip, resulting in that the software solution cannot be smoothly transplanted to other control chips without similar special function peripherals. Summary of the Invention

[0005] To provide a basic understanding of some aspects of the disclosed embodiments, a simple summary is given below. This summary is not a general review, nor is it intended to identify key / important elements or delineate the scope of protection of these embodiments, but rather serves as a preface to the detailed description that follows.

[0006] Embodiments of the present disclosure provide a method, device, and equipment for current waveform correction of a variable-frequency device to solve the technical problems of AC current sawtooth oscillation and distortion under a single-voltage loop control strategy in a variable-frequency device.

[0007] In some embodiments, the method includes:

[0008] Obtaining the DC bus voltage value of the variable-frequency device within the current period;

[0009] Performing single-voltage power factor PFC control based on the DC bus voltage value and the average value of the AC input current of the variable-frequency device within the current period to obtain the output value of the proportional-integral (PI) controller for the current period;

[0010] Performing differential compensation processing on the output value of the proportional-integral (PI) controller for the current period to obtain the duty ratio for the current period output, where the duty ratio differential compensation algorithm gain in the differential compensation processing is determined based on the DC bus voltage value and the voltage vector value required by the subsequent load;

[0011] Performing pulse-width modulation (PWM) correction for the current period on the AC input current of the variable-frequency device according to the duty ratio for the current period output.

[0012] In some embodiments, the device includes:

[0013] An acquisition module configured to obtain the DC bus voltage value of the variable-frequency device within the current period;

[0014] A PI control module configured to perform single-voltage power factor PFC control based on the DC bus voltage value and the average value of the AC input current of the variable-frequency device within the current period to obtain the output value of the proportional-integral (PI) controller for the current period;

[0015] A differential compensation module configured to perform differential compensation processing on the output value of the proportional-integral (PI) controller for the current period to obtain the duty ratio for the current period output, where the duty ratio differential compensation algorithm gain in the differential compensation processing is determined based on the DC bus voltage value and the voltage vector value required by the subsequent load;

[0016] A modulation correction module configured to perform pulse-width modulation (PWM) correction for the current period on the AC input current of the variable-frequency device according to the duty ratio for the current period output.

[0017] In some embodiments, a device for current waveform correction of a variable-frequency device includes: a processor and a memory storing program instructions, and the processor is configured to execute the above-mentioned current waveform correction method of the variable-frequency device when executing the program instructions.

[0018] In some embodiments, a variable-frequency device includes the device for current waveform correction of the variable-frequency device described above.

[0019] The device, method, and apparatus for current waveform correction of a variable-frequency device provided by the embodiments of the present disclosure can achieve the following technical effects:

[0020] By adopting the differential negative feedback control law and based on the predictability of the differential feedback for sensitive change trends, the gain of the duty cycle differential compensation algorithm can be obtained. That is, an effective early correction signal can be introduced for duty cycle distortion, thereby reducing duty cycle distortion to improve system stability. And the algorithm is simple and easy to implement. The operation of the gain of the duty cycle differential compensation algorithm does not depend on the AC input current, thereby overcoming the positive feedback amplification effect between AC current distortion and duty cycle distortion to a certain extent, and eliminating the adverse effect of AC current sampling error on the duty cycle compensation amount, thereby further improving the compensation effect, improving the PFC harmonic suppression effect and the system operation reliability.

[0021] The above general description and the following description are only exemplary and explanatory, and are not used to limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] One or more embodiments are exemplarily illustrated by corresponding drawings. These exemplary illustrations and the drawings do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements. The drawings do not constitute a proportional limitation, and among them:

[0023] Figure 1 is a principle block diagram of current waveform correction of a variable-frequency device in the related art;

[0024] Figure 2 is a principle block diagram of current waveform correction of a variable-frequency device in the embodiments of the present disclosure;

[0025] Figure 3 is a principle block diagram of differential compensation of duty cycle in the embodiments of the present disclosure;

[0026] Figure 4 is a schematic flowchart of a method for current waveform correction of a variable-frequency device in the embodiments of the present disclosure;

[0027] Figure 5 is a schematic structural diagram of a device for current waveform correction of a variable-frequency device provided by the embodiments of the present disclosure;

[0028] Figure 6 It is a schematic structural diagram of a current waveform correction device for a frequency conversion device provided by an embodiment of the present disclosure. Specific embodiments

[0029] In order to be able to understand the features and technical content of the embodiments of the present disclosure in more detail, the implementation of the embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. The attached drawings are for reference and illustration only and are not used to limit the embodiments of the present disclosure. In the following technical description, for the sake of explanation, numerous details are provided to give a thorough understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other instances, well-known structures and devices may be shown in a simplified manner to simplify the drawings.

[0030] In the description of the embodiments of the present disclosure, the terms "first", "second", etc. in the specification and claims of the embodiments of the present disclosure and the above-mentioned drawings are used to distinguish similar objects and do not necessarily have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so as to implement the embodiments of the present disclosure described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion.

[0031] Unless otherwise specified, the term "plurality" means two or more.

[0032] In the embodiments of the present disclosure, the character " / " means that the objects before and after are in an "or" relationship. For example, A / B means: A or B.

[0033] The term "and / or" is a description of the associated relationship of an object and means that three relationships can exist. For example, A and / or B means: A or B, or, the three relationships of A and B.

[0034] In the embodiments of the present disclosure, a duty ratio differential negative feedback compensation method is added to the current single voltage loop PFC control strategy to perform differential compensation on the output value of the PI controller, that is, an effective early correction signal can be introduced for duty ratio distortion, thereby reducing duty ratio distortion to improve system stability. Moreover, the operation of the duty ratio differential compensation algorithm gain does not depend on the AC input current, thereby overcoming the positive feedback amplification effect between AC current distortion and duty ratio distortion to a certain extent, and eliminating the adverse effect of AC current sampling error on the duty ratio compensation amount, thereby further improving the compensation effect.

[0035] Figure 1 It is a principle block diagram of current waveform correction of a frequency conversion device in the related art. As Figure 1As shown, a single - voltage - loop PFC control strategy is adopted for current waveform correction of a variable - frequency device. Among them, the DC - bus voltage value V of the variable - frequency device in the current period dc-fed , and the target bus - voltage value V of the variable - frequency device dc-ref , after the input boost - ratio calculation module performs PI control, the DC - bus voltage boost ratio is obtained. After passing through the boost - ratio stabilization module and the high - speed control module, the corresponding output duty cycle Duty[n] can be obtained.

[0036]

[0037] Among them, a set (Boost Ratio) is the DC - bus voltage boost ratio, and the AC current I mean is obtained by calculating the instantaneous value of the AC input current i ac through the average value.

[0038] It can be seen that in the related technology, due to the saturation of the PI regulator at low speed and light load, the boost ratio a set is a fixed value, that is, the boost ratio no longer changes with the change of the load current, resulting in AC - current distortion and saw - tooth oscillation. In the embodiments of the present disclosure, a duty - cycle differential negative - feedback compensation method is added to the single - voltage - loop PFC control strategy to perform differential compensation on the output value of the PI controller, that is, an effective early correction signal can be introduced for duty - cycle distortion, thereby reducing duty - cycle distortion to improve system stability.

[0039] Figure 2 is the principle block diagram of current waveform correction of a variable - frequency device in the embodiments of the present disclosure. Combining Figure 1 、 Figure 2 , in the embodiments of the present disclosure, differential compensation is added to the single - voltage - loop PFC control strategy, that is, the value output after passing through the boost - ratio calculation module, the boost - ratio stabilization module, and the high - speed control module needs to be subjected to differential - compensation processing before the output duty cycle can be obtained.

[0040] Figure 3 is the principle block diagram of differential - compensation duty cycle in the embodiments of the present disclosure. As Figure 3 shown, according to the DC - bus voltage value v dc [n] in the current period and the voltage - vector value v ref [n] required by the subsequent - stage load, the gain parameter calculation is performed to obtain the duty - cycle differential - compensation algorithm gain k D [n]. In some embodiments, the process of determining the duty - cycle differential - compensation algorithm gain k D [n] includes: according to formula (1), determining the duty - cycle differential - compensation algorithm gain k D [n].

[0041]

[0042] Among them, N is a scaling factor, which can be determined by debugging according to the system load. In some embodiments, N can take a value greater than 1000. Of course, the voltage vector value required by the subsequent load of the frequency conversion device is also determined according to the specific model, function, etc. of the frequency conversion load.

[0043] After determining the duty cycle differential compensation algorithm gain k D [n], the value output after passing through the boost ratio calculation module, the boost ratio stabilization module, and the high-speed control module can be subjected to differential compensation operation. In the embodiments of the present disclosure, it is the output value D of the current cycle proportional-integral PI controller PI [n], to obtain the duty cycle value D out [n] output in the current cycle.

[0044] In some embodiments, according to formula (2), the duty cycle value output in the current cycle is obtained.

[0045]

[0046] Among them, T S_PWM is the carrier period value of PWM; D PI [n] is the output value of the current cycle PI controller; D out [n - 1] is the duty cycle value output in the previous cycle; D out [n] is the duty cycle value output in the current cycle.

[0047] It can be seen that based on the predictability of the differential feedback for the sensitive change trend, an effective early correction signal can be introduced for the duty cycle distortion, thereby reducing the duty cycle distortion to improve the system stability. And the algorithm is simple and easy to implement. The operation of the duty cycle differential compensation algorithm gain does not depend on the AC input current, thereby overcoming the positive feedback amplification effect between the AC current distortion and the duty cycle distortion to a certain extent, and eliminating the adverse effect of the AC current sampling error on the duty cycle compensation amount, thereby further improving the compensation effect.

[0048] After determining the principle of the current waveform correction of the frequency conversion device in the embodiments of the present disclosure, the current waveform correction of the frequency conversion device can be performed.

[0049] Figure 4 is a schematic flow chart of a method for current waveform correction of a frequency conversion device in the embodiments of the present disclosure. Combining Figure 2 、 Figure 3 and Figure 4 , the process for current waveform correction of a frequency conversion device includes:

[0050] Step 401: Obtain the DC bus voltage value of the frequency conversion device within the current cycle.

[0051] Both single - voltage - loop PFC control and the determination of the gain of the duty - cycle differential compensation algorithm require the DC - bus voltage value. Therefore, discrete sampling is performed to obtain the DC - bus voltage value of the variable - frequency device in each cycle, and the cycle during which sampling is being performed for waveform correction is the current cycle.

[0052] Step 402: Based on the DC - bus voltage value and the average value of the AC input current of the variable - frequency device in the current cycle, perform single - voltage power - factor PFC control to obtain the output value of the proportional - integral (PI) controller in the current cycle.

[0053] Here, the single - voltage power - factor PFC control process in the related technology can be applied here. In some embodiments, obtaining the output value of the proportional - integral (PI) controller in the current cycle includes: performing PI control based on the DC - bus voltage value and the target bus - voltage value of the variable - frequency device to obtain an estimated boost ratio; obtaining an amplified AC value based on the estimated boost ratio and the average value of the AC input current in the current cycle; obtaining the output value of the proportional - integral (PI) controller in the current cycle based on the amplified AC value and the AC input - current value. It can be seen that after passing through the boost - ratio calculation module, the boost - ratio stabilization module, and the high - speed control module respectively, the output value D PI [n] of the proportional - integral (PI) controller in the current cycle can be obtained.

[0054] Step 403: Perform differential - compensation processing on the output value of the proportional - integral (PI) controller in the current cycle to obtain the duty - cycle value in the current cycle. Among them, the gain of the duty - cycle differential compensation algorithm in the differential - compensation processing is determined based on the DC - bus voltage value and the voltage - vector value required by the subsequent load.

[0055] Here, differential - compensation processing is performed on D PI [n]. Before performing the differential - compensation processing, it is also necessary to determine the gain k D [n] of the duty - cycle differential compensation algorithm based on the DC - bus voltage value and the voltage - vector value required by the subsequent load. D [n]. In some embodiments, according to formula (1), the gain k D [n] of the duty - cycle differential compensation algorithm is determined.

[0056]

[0057] Among them, N is a scaling factor, which can be determined according to system - load debugging. v dc [n] is the DC - bus voltage value, v ref [n] is the voltage - vector value required by the subsequent load, and k D [n] is the gain of the duty - cycle differential compensation algorithm.

[0058] Of course, n is the current time in the discrete - sampling process, that is, corresponding to the current cycle.

[0059] Then, according to k D [n], and formula (2), the duty ratio of the current cycle output after differential compensation can be obtained.

[0060]

[0061] Among them, T S_PWM is the carrier period value of PWM; D PI [n] is the output value of the PI controller in the current cycle; D out [n - 1] is the duty ratio of the previous cycle output; D out [n] is the duty ratio of the current cycle output.

[0062] Step 404: According to the duty ratio of the current cycle output, perform pulse width modulation (PWM) correction on the AC input current of the frequency conversion device in the current cycle.

[0063] By performing PWM correction on the AC input current of the frequency conversion device according to the duty ratio, the corrected current waveform can be obtained.

[0064] It can be seen that in the embodiments of the present disclosure, by adopting the differential negative feedback control law and based on the predictability of the differential feedback for the sensitive change trend, the gain of the duty ratio differential compensation algorithm is obtained. That is, an effective early correction signal can be introduced for the duty ratio distortion, thereby reducing the duty ratio distortion to improve the system stability. And the algorithm is simple and easy to implement. The operation of the duty ratio differential compensation algorithm gain does not depend on the AC input current, thus overcoming the positive feedback amplification effect between the AC current distortion and the duty ratio distortion to a certain extent, and eliminating the adverse impact of the AC current sampling error on the duty ratio compensation amount, thereby further improving the compensation effect, improving the PFC harmonic suppression effect and the system operation reliability.

[0065] Of course, the duty ratio of the output in each cycle needs to be saved. In this way, when calculating the duty ratio of the next cycle output, the duty ratio of the previous cycle output can be obtained.

[0066] According to the above process for correcting the current waveform of the frequency conversion device, a device for correcting the current waveform of the frequency conversion device can be constructed.

[0067] Figure 5 is a schematic structural diagram of a device for correcting the current waveform of a frequency conversion device provided by the embodiments of the present disclosure. As Figure 5 shown, the device for correcting the current waveform of the frequency conversion device includes: an acquisition module 510, a PI control module 520, a differential compensation module 530, and a modulation correction module 540.

[0068] The acquisition module 510 is configured to acquire the DC bus voltage value of the frequency conversion device within the current cycle.

[0069] The PI control module 520 is configured to perform single - voltage power factor PFC control based on the DC bus voltage value and the average value of the AC input current of the frequency - conversion device in the current period, and obtain the output value of the proportional - integral PI controller in the current period;

[0070] The differential compensation module 530 is configured to perform differential compensation processing on the output value of the proportional - integral PI controller in the current period to obtain the duty ratio of the output in the current period. Among them, the gain of the duty - ratio differential compensation algorithm in the differential compensation processing is determined according to the DC bus voltage value and the voltage vector value required by the subsequent load.

[0071] The modulation correction module 540 is configured to perform pulse - width modulation PWM correction of the AC input current of the frequency - conversion device in the current period according to the duty ratio of the output in the current period.

[0072] In some embodiments, the PI control module 520 includes:

[0073] The boost - ratio calculation module is configured to perform PI control according to the DC bus voltage value and the target bus voltage value of the frequency - conversion device to obtain the estimated boost ratio.

[0074] The boost - ratio stabilization module is configured to obtain the AC amplification value according to the estimated boost ratio and the average value of the AC input current in the current period.

[0075] The high - speed control module is configured to obtain the output value of the proportional - integral PI controller in the current period according to the AC amplification value and the AC input current value.

[0076] In some embodiments, it further includes: a gain determination module, which is configured to determine the gain of the duty - ratio differential compensation algorithm according to formula (1);

[0077]

[0078] where, v dc [n] is the DC bus voltage value, v ref [n] is the voltage vector value required by the subsequent load, k D [n] is the gain of the duty - ratio differential compensation algorithm, and N is the scaling factor.

[0079] In some embodiments, the differential compensation module is specifically configured to obtain the duty ratio of the output in the current period according to formula (2);

[0080]

[0081] where, T S_PWM is the carrier - period value of PWM; D PI[n] is the output value of the PI controller in the current cycle; D out [n - 1] is the duty ratio of the output in the previous cycle; D out [n] is the duty ratio of the output in the current cycle.

[0082] It can be seen that in this embodiment, the current waveform correction device for the variable-frequency device can adopt the differential negative feedback control law. Based on the predictability of the differential feedback for the sensitive change trend, the gain of the duty ratio differential compensation algorithm is obtained, that is, an effective early correction signal can be introduced for the duty ratio distortion, thereby reducing the duty ratio distortion to improve the system stability. And the algorithm is simple and easy to implement. The operation of the gain of the duty ratio differential compensation algorithm does not depend on the AC input current, thus overcoming the positive feedback amplification effect between the AC current distortion and the duty ratio distortion to a certain extent, and eliminating the adverse effect of the AC current sampling error on the duty ratio compensation amount, thereby further improving the compensation effect, improving the PFC harmonic suppression effect and the system operation reliability.

[0083] The embodiment of the present disclosure provides a current waveform correction device for a variable-frequency device, and its structure is as Figure 6 shown, including:

[0084] A processor 1000 and a memory 1001, and may further include a communication interface 1002 and a bus 1003. Among them, the processor 1000, the communication interface 1002, and the memory 1001 can complete mutual communication through the bus 1003. The communication interface 1002 can be used for information transmission. The processor 1000 can call the logical instructions in the memory 1001 to execute the current waveform correction method for the variable-frequency device in the above embodiment.

[0085] In addition, when the logical instructions in the above-mentioned memory 1001 are implemented in the form of software function units and sold or used as an independent product, they can be stored in a computer-readable storage medium.

[0086] The memory 1001, as a computer-readable storage medium, can be used to store software programs and computer-executable programs, such as the program instructions / modules corresponding to the method in the embodiment of the present disclosure. The processor 1000 executes functional applications and data processing by running the program instructions / modules stored in the memory 1001, that is, implements the current waveform correction method for the variable-frequency device in the above method embodiment.

[0087] The memory 1001 may include a program storage area and a data storage area. The program storage area may store an operating system and application programs required for at least one function. The data storage area may store data created according to the use of the terminal device and the like. In addition, the memory 1001 may include a high-speed random access memory and may also include a non-volatile memory.

[0088] An embodiment of the present disclosure provides a current waveform correction device for a variable frequency device, including: a processor and a memory storing program instructions. The processor is configured to execute a current waveform correction method for a variable frequency device when executing the program instructions.

[0089] An embodiment of the present disclosure provides a variable frequency device, including the above-mentioned current waveform correction device for a variable frequency device.

[0090] An embodiment of the present disclosure provides a computer-readable storage medium storing computer-executable instructions, and the computer-executable instructions are set to execute the above-mentioned current waveform correction method for a variable frequency device.

[0091] An embodiment of the present disclosure provides a computer program product. The computer program product includes a computer program stored on a computer-readable storage medium. The computer program includes program instructions. When the program instructions are executed by a computer, the computer is caused to execute the above-mentioned current waveform correction method for a variable frequency device.

[0092] The above-mentioned computer-readable storage medium may be a transient computer-readable storage medium or a non-transient computer-readable storage medium.

[0093] The technical solution of the embodiment of the present disclosure may be embodied in the form of a software product. The computer software product is stored in a storage medium and includes one or more instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in the embodiment of the present disclosure. The foregoing storage medium may be a non-transient storage medium, including: various media that can store program codes such as a USB flash drive, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk, or an optical disc, or may also be a transient storage medium.

[0094] The above description and the accompanying drawings fully illustrate the embodiments of the present disclosure so that those skilled in the art can practice them. Other embodiments may include structural, logical, electrical, process, and other changes. The embodiments merely represent possible variations. Unless explicitly required, the individual components and functions are optional, and the order of operations may vary. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. The scope of the embodiments of the present disclosure includes the entire scope of the claims and all available equivalents of the claims. When used in this application, although terms such as "first", "second", etc. may be used in this application to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, without changing the meaning of the description, the first element may be called the second element, and similarly, the second element may be called the first element, as long as all occurrences of "the first element" are consistently renamed and all occurrences of "the second element" are consistently renamed. The first element and the second element are both elements, but they may not be the same element. Moreover, the terms used in this application are only used to describe the embodiments and are not used to limit the claims. As used in the description of the embodiments and the claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to also include the plural forms. Similarly, as used in this application, the term "and / or" refers to any and all possible combinations including one or more of the associated listed items. Additionally, when used in this application, the term "comprise" and its variants "comprises" and / or "comprising", etc. mean the presence of the stated features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or groups thereof. Without further limitation, an element defined by the statement "comprising one..." does not exclude the presence of additional identical elements in the process, method, or device comprising the element. In this document, each embodiment may focus on the differences from other embodiments, and the same or similar parts among the embodiments may be referred to each other. For the methods, products, etc. disclosed in the embodiments, if they correspond to the method part disclosed in the embodiments, the relevant parts may refer to the description of the method part.

[0095] Those skilled in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner can depend on the specific application and design constraints of the technical solution. The skilled person can use different methods for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of the embodiments of the present disclosure. The skilled person can clearly understand that for the convenience and conciseness of description, the specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0096] In the embodiments disclosed herein, the disclosed methods, products (including but not limited to devices, equipment, etc.) can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units can be merely a logical function division, and there can be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Additionally, the couplings or direct couplings or communication connections shown or discussed with each other can be through some interfaces, and the indirect couplings or communication connections of the devices or units can be in electrical, mechanical, or other forms. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to implement this embodiment. Additionally, in the embodiments of the present disclosure, the various functional units can be integrated in one processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.

[0097] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to embodiments of the present disclosure. In this regard, each block in the flowchart or block diagram may represent a module, a segment of a program, or a portion of code, which contains one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions noted in the blocks may occur in a different order than noted in the accompanying drawings. For example, two consecutive blocks may actually be executed substantially in parallel, or they may sometimes be executed in the reverse order, depending on the functions involved. In the description corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different blocks may also occur in a different order than disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps may actually be executed substantially in parallel, or they may sometimes be executed in the reverse order, depending on the functions involved. Each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented by a dedicated hardware-based system that performs the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

Claims

1. A method for correcting the current waveform of a variable frequency device, characterized in that, including: Obtain the DC bus voltage value of the frequency conversion device within the current period; Perform single-voltage power factor PFC control based on the DC bus voltage value and the average value of the AC input current of the frequency conversion device within the current period to obtain the output value of the proportional-integral (PI) controller for the current period; Perform differential compensation processing on the output value of the proportional-integral (PI) controller for the current period to obtain the duty ratio of the current period output, wherein the gain of the duty ratio differential compensation algorithm in the differential compensation processing is determined based on the DC bus voltage value and the voltage vector value required by the subsequent load; Perform pulse-width modulation (PWM) correction for the current period on the AC input current of the frequency conversion device according to the duty ratio of the current period output; wherein the process of determining the gain of the duty ratio differential compensation algorithm includes: Determine the gain of the duty ratio differential compensation algorithm according to formula (1); Among them, v dc [n] is the DC bus voltage value, v ref [n] is the voltage vector value required by the subsequent load, k D [n] is the duty ratio differential compensation algorithm gain, and N is the scaling factor; The obtaining of the duty ratio of the current period output includes: Obtain the duty ratio of the current period output according to formula (2); Among them, T S_PWM is the carrier period value of the PWM; D PI [n] is the output value of the PI controller in the current period; D out [n - 1] is the duty cycle ratio of the previous period output; D out [n] is the duty cycle ratio of the current period output.

2. The method according to claim 1, wherein The obtaining of the output value of the proportional-integral (PI) controller for the current period includes: Perform PI control based on the DC bus voltage value and the target bus voltage value of the frequency conversion device to obtain an estimated boost ratio; Obtain an AC amplification value based on the estimated boost ratio and the average value of the AC input current within the current period; Obtain the output value of the proportional-integral (PI) controller for the current period based on the AC amplification value and the AC input current value.

3. A device for correcting the current waveform of a variable-frequency device, characterized in that, including: An acquisition module configured to obtain the DC bus voltage value of the frequency conversion device within the current period; A PI control module configured to perform single-voltage power factor PFC control based on the DC bus voltage value and the average value of the AC input current of the frequency conversion device within the current period to obtain the output value of the proportional-integral (PI) controller for the current period; A differential compensation module configured to perform differential compensation processing on the output value of the proportional-integral (PI) controller for the current period to obtain the duty ratio of the current period output, wherein the gain of the duty ratio differential compensation algorithm in the differential compensation processing is determined based on the DC bus voltage value and the voltage vector value required by the subsequent load; A modulation correction module configured to perform pulse-width modulation (PWM) correction for the current period on the AC input current of the frequency conversion device according to the duty ratio of the current period output; A gain determination module configured to determine the gain of the duty ratio differential compensation algorithm according to formula (1); Among them, v dc [n] is the DC bus voltage value, v ref [n] is the voltage vector value required by the subsequent load, k D [n] is the duty ratio differential compensation algorithm gain, and N is the scaling factor; The differential compensation module is specifically configured to obtain the duty ratio of the current period output according to formula (2); Among them, T S_PWM is the carrier period value of the PWM; D PI [n] is the output value of the PI controller in the current period; D out [n - 1] is the duty cycle ratio of the previous period output; D out [n] is the duty cycle ratio of the current period output.

4. The device according to claim 3, characterized in that, The PI control module includes: A boost ratio calculation module configured to perform PI control based on the DC bus voltage value and the target bus voltage value of the frequency conversion device to obtain an estimated boost ratio; A boost ratio stabilization module configured to obtain an AC amplification value based on the estimated boost ratio and the average value of the AC input current within the current period; A high-speed control module configured to obtain the output value of the proportional-integral (PI) controller for the current period based on the AC amplification value and the AC input current value.

5. A device for correcting the current waveform of a frequency conversion device, characterized in that, including: A processor and a memory storing program instructions, characterized in that the processor is configured to execute the method according to claim 1 or 2 when executing the program instructions.

6. A frequency conversion device, characterized in that, Comprising: A device for current waveform correction of a variable frequency device according to claim 3 or 5.

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