Dead-time compensation method and device, computer device and storage medium

Abstract

The embodiment of the application belongs to the technical field of power electronic control, and relates to a dead-time compensation method, comprising collecting modulation control data of a plurality of level converters; confirming a target dead-time compensation algorithm based on the modulation control data; processing the modulation control data based on the target dead-time compensation algorithm to obtain a target dead-time compensation value; and updating a harmonic state of the plurality of level converters based on the target dead-time compensation value. The application also provides a dead-time compensation device, a computer device and a storage medium. According to the capacitor voltage, the inverter-side current reference value and the original modulation wave, the current charging / discharging direction and whether the positive and negative modulation waves overlap are judged, so that whether the positive and negative modulation waves need dead-time compensation and the compensation direction are determined, and the 6th harmonic caused by the dead-time is effectively reduced.

Description

Technical Field

[0001] This application relates to the field of power electronic control technology, and in particular to dead zone compensation methods, devices, computer equipment and storage media. Background Technology

[0002] With the rapid development of power electronics technology, multilevel converters have been widely used in medium- and high-voltage, high-power applications. However, due to the special nature of the multilevel converter topology, the midpoint potential of the DC-side capacitor fluctuates with changes in the load current. This imbalance in the midpoint potential can lead to distortion of the output voltage waveform, uneven voltage stress on switching devices, and even system instability.

[0003] To address the aforementioned issues, virtual vectors synthesized using virtual space vector modulation technology can effectively suppress midpoint potential fluctuations. However, since switching devices must have a dead zone to prevent shoot-through during turn-on / turn-off, the dead zone inevitably introduces duty cycle deviation, 6th harmonic, and THD rise.

[0004] However, existing dead zone compensation methods only compensate for one-sided modulation waves based on capacitor voltage and current reference values. They cannot compensate for both positive and negative modulation waves simultaneously in the overlapping region, and will still leave obvious 6th harmonics. Summary of the Invention

[0005] The purpose of this application is to provide a dead zone compensation method, apparatus, computer equipment, and storage medium to eliminate abnormal harmonics in the overlapping region of positive and negative modulation waves when a multilevel converter uses virtual space vector modulation.

[0006] To address the aforementioned technical problems, this application provides a dead-time compensation method applied to a level converter, employing the following technical solution: Acquire modulation control data from multiple level converters; The target dead zone compensation algorithm is confirmed based on the modulation control data; The modulation control data is processed based on the target dead zone compensation algorithm to obtain the target dead zone compensation value; The harmonic states of the multiple level converters are updated based on the target dead-zone compensation value. Further, the step of acquiring the modulation control data of the level converters specifically includes: The capacitor voltage data, raw modulation wave signal, and inverter side current reference value of multiple level converters are collected as modulation control data for the level converters.

[0007] Furthermore, the step of confirming the target dead zone compensation algorithm based on the modulation control data specifically includes: Based on the capacitor voltage data and the original modulation wave signal, the target compensation direction is determined, which includes the positive modulation wave compensation direction and the negative modulation wave compensation direction. Based on the target compensation direction, a target dead zone compensation algorithm is determined from a preset dead zone compensation algorithm, wherein the positive modulation wave compensation direction corresponds to the first target dead zone compensation algorithm, and the negative modulation wave compensation direction corresponds to the second target dead zone compensation algorithm.

[0008] Furthermore, the target dead-zone compensation value includes positive modulation compensation data and negative modulation compensation data. The step of processing the modulation control data based on the target dead-zone compensation algorithm to obtain the target dead-zone compensation value specifically includes: When the target compensation direction is the positive modulation wave compensation direction, the modulation control data is compensated for the first dead zone based on the first target dead zone compensation algorithm to obtain the positive modulation compensation data. When the target compensation direction is the negative modulation wave compensation direction, the modulation control data is subjected to a second compensation process based on the second target dead zone compensation algorithm to obtain the negative modulation compensation data.

[0009] Furthermore, the step of determining the target compensation direction based on the capacitor voltage data and the original modulated wave signal specifically includes: When the capacitor voltage data is greater than zero, the target compensation direction is determined to be the positive modulation wave compensation direction, or When the capacitor voltage data is less than zero and the original positive modulation wave is greater than zero, the target compensation direction is determined to be the positive modulation wave compensation direction.

[0010] Furthermore, the step of determining the target compensation direction based on the capacitor voltage data and the original modulated wave signal further includes: When the capacitor voltage data is less than zero, the target compensation direction is determined to be the negative modulation wave compensation direction, or When the capacitor voltage data is greater than zero and the original negative modulation wave is less than one, the target compensation direction is determined to be the negative modulation wave compensation direction.

[0011] Furthermore, the step of compensating the plurality of level converters based on the target dead-zone compensation value and updating the harmonic state of the level converters specifically includes: Obtain the overlapping region of positive and negative modulation waves in the plurality of level converters; Based on the positive modulation compensation data and the negative modulation compensation data, synchronous compensation processing is performed on the overlapping region of the positive and negative modulation waves to update the harmonic state of the multiple level converters.

[0012] To address the aforementioned technical problems, this application also provides a dead-time compensation device applied to a level converter, employing the following technical solution: The acquisition module is used to acquire modulation control data from multiple level converters; The confirmation module is used to confirm the target dead zone compensation algorithm based on the modulation control data; The processing module is used to process the modulation control data based on the target dead zone compensation algorithm to obtain the target dead zone compensation value; An update module is used to update the harmonic state of the level converter based on the target dead zone compensation value.

[0013] To address the aforementioned technical problems, this application also provides a computer device that employs the following technical solution: A computer device includes a memory and a processor, the memory storing computer-readable instructions, wherein the processor, when executing the computer-readable instructions, implements the steps of the dead-time compensation method.

[0014] To address the aforementioned technical problems, this application also provides a computer-readable storage medium, employing the technical solution described below: A computer-readable storage medium, characterized in that the computer-readable storage medium stores computer-readable instructions, which, when executed by a processor, implement the steps of the dead-zone compensation method.

[0015] Compared with the prior art, the embodiments of this application have the following main advantages: This application embodiment employs a dead-zone compensation method, including: acquiring modulation control data from multiple level converters; confirming a target dead-zone compensation algorithm based on the modulation control data; processing the modulation control data based on the target dead-zone compensation algorithm to obtain a target dead-zone compensation value; updating the harmonic state of the multiple level converters based on the target dead-zone compensation value; and determining whether the positive and negative modulation waves need dead-zone compensation and the compensation direction by judging the current charging and discharging direction and whether the positive and negative modulation waves overlap based on the capacitor voltage, inverter side current reference value, and original modulation wave, thereby effectively reducing the 6th harmonic caused by the dead zone. Attached Figure Description

[0016] To more clearly illustrate the solutions in this application, the accompanying drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1This is an exemplary architecture diagram to which this application can be applied; Figure 2 A flowchart of an embodiment of the dead zone compensation method according to this application; Figure 3 This is a schematic diagram of one embodiment of the dead zone compensation device according to this application; Figure 4 This is a schematic diagram of the structure of one embodiment of the computer device according to this application; Figure 5 For positive and negative modulated waves using traditional dead-zone compensation methods; Figure 6 The waveforms of the inverter side current and capacitor voltage of phase AB using the traditional dead-time compensation method are shown. Figure 7 The sampled value of the inverter side current of the dq0 axis using the traditional dead-time compensation method; Figure 8 For positive and negative modulated waves using the dead-zone compensation method of this application; Figure 9 The waveforms of the inverter side current and capacitor voltage of phase AB using the dead-time compensation method of this application; Figure 10 The sampled value of the dq0 axis inverter side current using the dead zone compensation method of this application. Detailed Implementation

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application, are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0019] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0020] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0021] like Figure 1 As shown, the system architecture 100 of the dead zone compensation system may include a terminal device 101, a network 102, and a server 103. The terminal device 101 may be a laptop computer 1011, a tablet computer 1012, or a mobile phone 1013. The network 102 is used as a medium to provide a communication link between the terminal device 101 and the server 103. The network 102 may include various connection types, such as wired or wireless communication links or fiber optic cables.

[0022] Users can use terminal device 101 to interact with server 103 via network 102 to receive or send messages, etc. Various communication client applications can be installed on terminal device 101, such as web browser applications, shopping applications, search applications, instant messaging tools, email clients, social media platform software, etc.

[0023] Terminal device 101 can be various electronic devices with a display screen and support web browsing. In addition to laptops 1011, tablets 1012, or mobile phones 1013, terminal device 101 can also be an e-book reader, an MP3 player (Moving Picture Experts Group Audio Layer III), an MP4 player (Moving Picture Experts Group Audio Layer IV), a laptop computer, and a desktop computer, etc.

[0024] Server 103 can be a server that provides various services, such as a backend server that provides support for the pages displayed on terminal device 101.

[0025] It should be noted that the dead zone compensation method provided in this application embodiment is generally executed by a server / terminal device, and correspondingly, the dead zone compensation device is generally set in the server / terminal device.

[0026] It should be understood that Figure 1 The number of terminal devices, networks, and servers shown is merely illustrative. Depending on implementation needs, any number of terminal devices, networks, and servers can be included.

[0027] Continue to refer to Figure 2 The diagram illustrates a flowchart of an embodiment of the dead-zone compensation method according to this application. The dead-zone compensation method includes the following steps: Step S201: Collect modulation control data from multiple level converters.

[0028] In this embodiment, the dead zone compensation method described above can be deployed in a dead zone compensation platform. This platform can be constructed using a server or server cluster. The server or server cluster can be any electronic device with data transmission and data storage functions. The electronic device on which the dead zone compensation method runs (e.g., Figure 1 The server / terminal device shown can acquire modulation control data from multiple level converters via wired or wireless connections. It should be noted that the aforementioned wireless connection methods may include, but are not limited to, 3G / 4G / 5G connections, WiFi connections, Bluetooth connections, WiMAX connections, Zigbee connections, UWB (ultra-wideband) connections, and other currently known or future-developed wireless connection methods.

[0029] In this embodiment, the aforementioned level converter can be a diode-clamped three-level converter, a T-type three-level converter, or other power electronic converter devices employing a multi-level topology.

[0030] The aforementioned modulation control data may include control quantities such as capacitor voltage data, inverter side current reference value, original positive and negative modulation wave signals, and dead zone duty cycle parameters collected in real time during the operation of the level converter. These data serve as input parameters for determining the compensation direction and executing the dead zone compensation algorithm, and are used to dynamically adjust the dead zone compensation value and update the harmonic state under different operating conditions, thereby achieving a more accurate level converter control effect.

[0031] In this embodiment, the modulation control data of each level converter can be acquired in real time by setting data acquisition modules in the control units of multiple level converters or by remote acquisition through a centralized monitoring system.

[0032] Specifically, the detailed implementation process of collecting modulation and control data from multiple level converters will be described in further detail in subsequent specific embodiments of this application, and will not be elaborated upon here.

[0033] Step S202: Confirm the target dead zone compensation algorithm based on modulation control data.

[0034] In this embodiment, the target dead zone compensation algorithm can be any of a variety of dead zone compensation algorithms stored in the dead zone compensation system in advance, such as a positive modulation wave compensation algorithm or a negative modulation wave compensation algorithm based on the capacitor voltage and the original modulation wave signal to determine the direction. Specifically, the aforementioned target dead zone compensation algorithm can include a variety of common algorithm types, such as a fixed proportional compensation algorithm based on capacitor voltage threshold judgment, an adaptive dead zone compensation algorithm based on inverter side current reference value, a dynamic dead zone compensation algorithm based on model predictive control (MPC), and an intelligent dead zone compensation algorithm based on fuzzy control or neural networks. The above algorithms can be used individually or in combination according to different operating conditions to achieve fast, accurate and robust dead zone compensation in multilevel converters of different types and power levels.

[0035] Specifically, the implementation process of the target dead zone compensation algorithm based on modulation control data will be further described in detail in subsequent specific embodiments of this application, and will not be elaborated on here.

[0036] Step S203: Process the modulation control data based on the target dead zone compensation algorithm to obtain the target dead zone compensation value.

[0037] In this embodiment, the target dead zone compensation value can be a compensation amount calculated by the control system based on the capacitor voltage, the inverter side current reference value, the original positive and negative modulation wave signals and the dead zone duty cycle, and is used to synchronously correct the positive and negative modulation waves.

[0038] Specifically, the detailed implementation process of processing modulation control data based on the target dead zone compensation algorithm to obtain the target dead zone compensation value will be further described in subsequent specific embodiments of this application, and will not be elaborated on here.

[0039] Step S204: Update the harmonic state of multiple level converters based on the target dead zone compensation value.

[0040] In this embodiment, the harmonic state of the aforementioned level converter can refer to various parameters characterizing the harmonic properties of the output voltage or current of the level converter, such as the amplitude, phase, total harmonic distortion (THD), ratio of fundamental current to harmonic current, harmonic components of dq-axis current, and harmonic spectrum of grid current, etc., of each harmonic (especially the 6th harmonic). These harmonic state data can be collected in real time by the built-in harmonic analysis module or external monitoring equipment to reflect the waveform quality and control effect of the level converter before and after compensation, and serve as the basis for subsequent compensation algorithm adjustment, thereby ensuring that multiple level converters maintain low harmonic and high stability output performance under different operating conditions.

[0041] In one possible embodiment, after calculating the positive and negative modulation compensation data, the compensation values ​​can be synchronously written into the control modules of multiple level converters. Compensation is performed simultaneously on the overlapping areas of the positive and negative modulation waves, and the output voltage or current waveforms of each converter are corrected in real time. Fourier analysis is performed on the output of each level converter through the built-in harmonic analysis module or an external monitoring system to dynamically update parameters such as the harmonic components, THD value, or sixth harmonic amplitude of the dq axis current of each device. The control strategy is adjusted according to the updated harmonic state, so that low harmonic and high stability operation can be maintained when multiple level converters are running in parallel or independently.

[0042] This application employs a dead-zone compensation method, including: collecting modulation control data from multiple level converters; confirming a target dead-zone compensation algorithm based on the modulation control data; processing the modulation control data based on the target dead-zone compensation algorithm to obtain a target dead-zone compensation value; updating the harmonic state of the multiple level converters based on the target dead-zone compensation value; and determining whether the positive and negative modulation waves need dead-zone compensation and the compensation direction by judging the current charging and discharging direction and whether the positive and negative modulation waves overlap based on the capacitor voltage, inverter side current reference value, and original modulation wave, thereby effectively reducing the 6th harmonic caused by the dead zone.

[0043] In some alternative implementations, step S201 includes the following steps: The capacitor voltage data, raw modulation wave signal, and inverter side current reference value of multiple level converters are collected as modulation control data for the level converters.

[0044] In this embodiment, the above-mentioned capacitor voltage data may refer to the real-time voltage measurement value of the capacitors at both ends of the DC bus midpoint of the multilevel converter or its equivalent value obtained by filtering and sampling, which is used to reflect the change of the DC side midpoint potential. The aforementioned raw modulated wave signals can refer to the positive and negative modulated wave data output by the controller when using virtual space vector modulation, without dead-zone compensation processing. This includes waveform information such as m+ and m-. The positive modulated wave data refers to the raw modulated waveform data generated by the control system when using virtual space vector modulation or other PWM modulation methods, used to drive the upper bridge arm or positive polarity switching device, and is usually denoted as m+. The negative modulated wave data refers to the raw modulated waveform data generated under the same control system, used to drive the lower bridge arm or negative polarity switching device, and is usually denoted as m-. These two types of modulated wave data can be directly calculated by a digital signal processor (DSP), field-programmable gate array (FPGA), or controller software, or can be read in real-time from the hardware PWM output through a signal acquisition interface and used as the basic input for the dead-zone compensation algorithm.

[0045] The aforementioned inverter-side current reference value can refer to the expected output current value or dq-axis current reference value generated based on the system operating status, load conditions, or power command. It is used as an input parameter for the control algorithm to determine the compensation direction and calculate the compensation amount, thereby providing complete input data support for subsequent dead zone compensation.

[0046] In one possible embodiment, real-time capacitor voltage data can be obtained by installing voltage sensors at both ends of the DC bus midpoint of each level converter; positive and negative modulation wave signals can be directly read from the output of the PWM modulation unit or digital signal processor (DSP) of the controller as the original modulation wave signals; in the inverter-side current detection circuit or the host computer control system, the inverter-side current reference value can be calculated by Hall current sensor, sampling resistor or control command, and the above three types of data can be transmitted to the centralized controller through industrial Ethernet, CAN bus or high-speed optical fiber to form unified modulation control data for multiple level converters, providing accurate input for the dead-zone compensation algorithm.

[0047] In some alternative implementations, step S202 includes the following steps: Based on the capacitor voltage data and the original modulated wave signal, the target compensation direction is determined. The target dead zone compensation algorithm is determined from the preset dead zone compensation algorithms based on the target compensation direction, wherein the positive modulation wave compensation direction corresponds to the first target dead zone compensation algorithm and the negative modulation wave compensation direction corresponds to the second target dead zone compensation algorithm.

[0048] In this embodiment, the target compensation direction includes a positive modulation wave compensation direction and a negative modulation wave compensation direction. Specifically, the positive modulation wave compensation direction can refer to the direction in which the control system selects to perform compensation processing on the positive modulation wave m+ when the capacitor voltage data is greater than zero, or when the capacitor voltage data is less than zero and the original positive modulation wave signal is greater than zero; the negative modulation wave compensation direction can refer to the direction in which the control system selects to perform compensation processing on the negative modulation wave m- when the capacitor voltage data is less than zero, or when the capacitor voltage data is greater than zero and the original negative modulation wave signal is less than a preset threshold (1). Through such directional division, the compensation strategy can be dynamically determined under different operating conditions to achieve accurate compensation of positive and negative modulation waves and harmonic suppression.

[0049] In this embodiment, the aforementioned first target dead zone compensation algorithm can be a compensation algorithm designed for the positive modulation wave compensation direction, such as a positive modulation compensation formula calculated based on capacitor voltage data, inverter side current reference value, and dead zone duty cycle parameter. Specifically, the aforementioned first target dead zone compensation algorithm can be as follows: ; Where M+ is the positive modulation wave after dead-zone compensation, d dtIt is the dead zone duty cycle, i ref It is the current reference value, I th It is the current threshold. When the current reference value is greater than the threshold I... th When the current reference value is less than -I, a compensation amount is added to the positive modulation wave to increase the duty cycle; th When the positive modulation wave is reduced, the compensation amount is decreased to lower the duty cycle; when the current reference value is located at [-I th， I th When the signal is in the specified range, no compensation is performed, and the original signal is output directly.

[0050] In this embodiment, the above-mentioned second target dead zone compensation algorithm can be, specifically, as follows: ; Where M- is the negative modulation wave after dead-zone compensation, d dt It is the dead zone duty cycle, i ref It is the current reference value, I th It is the current threshold. When the current reference value is greater than the threshold I... th When the current reference value is less than -I, a compensation amount is added to the negative modulation wave; th When the current reference value is located at [-I], the compensation amount is reduced for the negative modulation wave; when the current reference value is located at [-I], the compensation amount is reduced for the negative modulation wave. th， I th When the signal is in the specified range, no compensation is performed, and the original signal is output directly.

[0051] By determining the target compensation direction based on capacitor voltage data and the original modulated wave signal, and automatically matching the first or second target dead zone compensation algorithm from the preset dead zone compensation algorithm library, differentiated and directional compensation control for positive and negative modulated waves is achieved, avoiding the harmonic residue problem caused by traditional methods that only compensate for a single waveform; this method can select the optimal compensation strategy in real time and dynamically under different operating conditions.

[0052] In some alternative implementations, step S203 includes: When the target compensation direction is the positive modulation wave compensation direction, the modulation control data is compensated for the first dead zone based on the first target dead zone compensation algorithm to obtain positive modulation compensation data. When the target compensation direction is the positive modulation wave compensation direction, the modulation control data is processed by the second target dead zone compensation algorithm to obtain negative modulation compensation data.

[0053] In this embodiment, the aforementioned positive modulation compensation data may refer to the compensation amount obtained after correcting the original positive modulation wave signal m+ based on the first target dead zone compensation algorithm, for example, according to M+=m+±d dtThe duty cycle is dynamically adjusted to match the current reference value and current threshold on the inverter side, thereby compensating for the dead zone effect of the positive modulation wave. The aforementioned negative modulation compensation data can refer to the compensation amount obtained after correcting the original negative modulation wave signal m- based on the second target dead zone compensation algorithm, for example, according to M-=m-±d dt The form of the _ is dynamically adjusted to synchronously compensate for the dead-zone effect of the negative modulation wave under different operating conditions. By generating compensation data for the positive and negative modulation waves separately and using them synchronously in the overlapping area, the 6th harmonic and total harmonic distortion (THD) can be significantly reduced, improving the output current quality and system stability of the multilevel converter.

[0054] In some alternative implementations, the step "determining the target compensation direction based on capacitor voltage data and the original modulated wave signal" includes the following steps: When the capacitor voltage data is greater than zero, the target compensation direction is determined to be the positive modulation wave compensation direction, or When the capacitor voltage data is less than zero and the original positive modulation wave is greater than zero, the target compensation direction is determined to be the positive modulation wave compensation direction.

[0055] When the capacitor voltage data is less than zero, the target compensation direction is determined to be the negative modulation wave compensation direction, or When the capacitor voltage data is greater than zero and the original negative modulation wave is less than one, the target compensation direction is determined to be the negative modulation wave compensation direction.

[0056] In one possible embodiment, the above-described method of determining the target compensation direction based on capacitor voltage data and the original modulation wave signal is illustrated as follows: For example, if the measured capacitor voltage data of a three-level converter is +50V, the system automatically determines the target compensation direction as the positive modulation wave compensation direction. Similarly, when the capacitor voltage data is -30V and the original positive modulation wave signal m+ = 0.6, it will also be determined as the positive modulation wave compensation direction. Conversely, when the capacitor voltage data is -40V, the system directly determines it as the negative modulation wave compensation direction; or when the capacitor voltage data is +20V and the original negative modulation wave signal m- = 0.8 (less than the preset threshold 1), it is also determined as the negative modulation wave compensation direction. Through this judgment logic, the control system can dynamically select the compensation direction under different operating conditions to ensure that the positive and negative modulation waves receive the most suitable dead-zone compensation.

[0057] In some alternative implementations, step S204 includes the following steps: Obtain the overlapping region of positive and negative modulation waves in multiple level converters; Synchronous compensation processing is performed on the overlapping area of ​​positive and negative modulation waves based on positive and negative modulation compensation data, and the harmonic state of multiple level converters is updated.

[0058] In this embodiment, the aforementioned positive and negative modulation wave overlap region can refer to the waveform segment in which the positive modulation wave data m+ and the negative modulation wave data m- are simultaneously non-zero and intersect during the operation of the multilevel converter, that is, the region where the numerical range or time period of the two overlaps. This region usually appears at the moment when the positive and negative modulation waves alternate under virtual space vector modulation.

[0059] In this embodiment, the aforementioned synchronous compensation processing refers to the control system simultaneously calling the first target dead zone compensation algorithm and the second target dead zone compensation algorithm after detecting an overlapping area between the positive and negative modulation waves. The positive and negative modulation compensation data are calculated in parallel with the same sampling period and time window and synchronously written into the converter control module. The positive and negative modulation waves are compensated and corrected at the same time. This synchronous compensation can be implemented in parallel computing in a digital signal processor (DSP) or FPGA, or it can be implemented by uniformly issuing compensation instructions through the host computer control software. This ensures that the positive and negative modulation waves maintain a consistent compensation effect in the overlapping area, effectively reducing the 6th harmonic and THD, and improving the output current waveform quality and system stability of the multilevel converter.

[0060] In one possible embodiment, the dead-zone compensation system first acquires capacitor voltage, inverter-side current reference values, and original positive and negative modulation wave signals in real time by arranging voltage and current sensors and signal acquisition interfaces on multiple level converters. In the control module, the amplitude, phase, and duty cycle of m+ and m- are compared to determine the overlapping area of ​​the positive and negative modulation waves. When the overlapping area is detected, the first and second target dead-zone compensation algorithms are called to calculate the positive modulation compensation data M+ and the negative modulation compensation data M-, respectively. The compensation amount is synchronously written into the control module of each converter in the same sampling period to compensate and correct the positive and negative modulation waves simultaneously. After the compensation is completed, the harmonic analysis module acquires the harmonic amplitude, THD, and other indicators of each converter and updates the harmonic status, thereby enabling multiple devices to operate stably and with low harmonics under various operating conditions.

[0061] In one possible embodiment, for example, the DC bus voltage is 830V, the rated power is 125kW, the effective value of the grid voltage is 230V, the grid frequency is 50Hz, the switching frequency is 16kHz, the dead zone duty cycle is 4%, and the dead zone compensation current threshold is 10A.

[0062] like Figure 5 , Figure 6 and Figure 7 The diagram shows the effect of using the traditional dead-zone compensation method. When using the traditional dead-zone compensation method, only one of the modulating waves is compensated in the overlapping area of ​​the positive and negative modulating waves, resulting in severe distortion of the inverter side current waveform. The total harmonic distortion (THD) of the grid current reaches 6.56%, and the amplitudes of the 6th harmonics of the dq axis current are 30V and 60V, respectively.

[0063] like Figure 8 , Figure 9 and Figure 10 The diagram shown illustrates the effect of using the dead-zone compensation method of this invention. When using the dead-zone compensation method of this invention, both positive and negative modulation waves are compensated simultaneously in the overlapping region, resulting in a significant improvement in the inverter-side current waveform. The grid current THD is reduced to 3.91%, and the amplitude of the 6th harmonic of the dq-axis current is essentially reduced to 0, achieving significant harmonic suppression and waveform quality improvement.

[0064] It is understood that in the specific implementation of this application, data related to xx and so on are involved. When the embodiments in this application are applied to specific products or technologies, user permission or consent is required, and the collection, use and processing of related data must comply with the relevant laws, regulations and standards of the relevant countries and regions.

[0065] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by instructing related hardware through computer-readable instructions. These computer-readable instructions can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above methods. The aforementioned storage medium can be a non-volatile storage medium such as a magnetic disk, optical disk, or read-only memory (ROM), or random access memory (RAM).

[0066] It should be understood that although the steps in the flowcharts of the accompanying figures are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the accompanying figures may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the sub-steps or stages of other steps.

[0067] Further reference Figure 3 As a response to the above Figure 2 To implement the method shown, this application provides an embodiment of a dead-zone compensation device, which is similar to... Figure 2 Corresponding to the method embodiments shown, this device can be specifically applied to various electronic devices.

[0068] like Figure 3As shown, the dead zone compensation device 300 described in this embodiment includes: a data acquisition module 301, a confirmation module 302, a processing module 303, and an update module 304. Wherein: Acquisition module 301 is used to acquire modulation control data of multiple level converters; Confirmation module 302 is used to confirm the target dead zone compensation algorithm based on the modulation control data; Processing module 303 is used to process the modulation control data based on the target dead zone compensation algorithm to obtain the target dead zone compensation value; The update module 304 is used to update the harmonic state of the level converter based on the target dead zone compensation value.

[0069] The acquisition module 301 includes: The acquisition submodule is used to acquire capacitor voltage data, raw modulation wave signals, and inverter-side current reference values ​​of multiple level converters as modulation control data for the level converters.

[0070] The confirmation module 302 includes: The first determining submodule is used to determine the target compensation direction based on the capacitor voltage data and the original modulation wave signal. The target compensation direction includes a positive modulation wave compensation direction and a negative modulation wave compensation direction. The second determining submodule is used to determine a target dead zone compensation algorithm from a preset dead zone compensation algorithm based on the target compensation direction, wherein the positive modulation wave compensation direction corresponds to the first target dead zone compensation algorithm and the negative modulation wave compensation direction corresponds to the second target dead zone compensation algorithm.

[0071] The processing module 303 includes: The first processing submodule is used to perform first dead-zone compensation on the modulation control data based on the first target dead-zone compensation algorithm when the target compensation direction is the positive modulation wave compensation direction, so as to obtain the positive modulation compensation data. The second processing submodule is used to perform a second compensation process on the modulation control data based on the second target dead zone compensation algorithm when the target compensation direction is the negative modulation wave compensation direction, so as to obtain the negative modulation compensation data.

[0072] The first determining submodule includes: The first determining unit is configured to determine that the target compensation direction is a positive modulation wave compensation direction when the capacitor voltage data is greater than zero, or The second determining unit is used to determine the target compensation direction as the positive modulation wave compensation direction when the capacitor voltage data is less than zero and the original positive modulation wave is greater than zero.

[0073] The first determining submodule further includes: The third determining unit is used to determine that the target compensation direction is the negative modulation wave compensation direction when the capacitor voltage data is less than zero, or The fourth determining unit is used to determine the target compensation direction as the negative modulation wave compensation direction when the capacitor voltage data is greater than zero and the original negative modulation wave is less than one.

[0074] The update module 304 includes: The acquisition submodule is used to acquire the overlapping region of positive and negative modulation waves in the plurality of level converters; The update submodule is used to perform synchronous compensation processing on the overlapping area of ​​the positive and negative modulation waves based on the positive modulation compensation data and the negative modulation compensation data, and update the harmonic state of the multiple level converters.

[0075] In this embodiment, the dead-zone compensation method includes: collecting modulation control data from multiple level converters; confirming a target dead-zone compensation algorithm based on the modulation control data; processing the modulation control data based on the target dead-zone compensation algorithm to obtain a target dead-zone compensation value; updating the harmonic state of the multiple level converters based on the target dead-zone compensation value; and determining whether the positive and negative modulation waves need dead-zone compensation and the compensation direction by judging the current charging and discharging direction and whether the positive and negative modulation waves overlap based on the capacitor voltage, inverter side current reference value, and original modulation wave, thereby effectively reducing the 6th harmonic caused by the dead zone.

[0076] In this embodiment, the operations performed by the above-mentioned units or modules correspond one-to-one with the steps of the dead zone compensation method in the above-described implementation method, and will not be repeated here.

[0077] To address the aforementioned technical problems, embodiments of this application also provide a computer device. Please refer to [link / reference needed]. Figure 4 , Figure 4 This is a basic structural block diagram of the computer device in this embodiment.

[0078] The computer device 4 includes a memory 41, a processor 42, and a network interface 43 that are interconnected via a system bus. It should be noted that only the computer device 4 with components 41-43 is shown in the figure; however, it should be understood that it is not required to implement all the shown components, and more or fewer components can be implemented alternatively. Those skilled in the art will understand that the computer device described here is a device capable of automatically performing numerical calculations and / or information processing according to pre-set or stored instructions, and its hardware includes, but is not limited to, microprocessors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), embedded devices, etc.

[0079] The computer device can be a desktop computer, laptop, handheld computer, or cloud server, etc. The computer device can interact with the user via a keyboard, mouse, remote control, touchpad, or voice control.

[0080] The memory 41 includes at least one type of readable storage medium, including flash memory, hard disk, multimedia card, card-type memory (e.g., SD or DX memory), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memory, disk, optical disk, etc. In some embodiments, the memory 41 may be an internal storage unit of the computer device 4, such as the hard disk or memory of the computer device 4. In other embodiments, the memory 41 may also be an external storage device of the computer device 4, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., equipped on the computer device 4. Of course, the memory 41 may include both the internal storage unit and its external storage device of the computer device 4. In this embodiment, the memory 41 is typically used to store the operating system and various application software installed on the computer device 4, such as computer-readable instructions for dead-zone compensation methods. In addition, the memory 41 can also be used to temporarily store various types of data that have been output or will be output.

[0081] In some embodiments, the processor 42 may be a central processing unit (CPU), a controller, a microcontroller, a microprocessor, or other data processing chip. The processor 42 is typically used to control the overall operation of the computer device 4. In this embodiment, the processor 42 is used to execute computer-readable instructions stored in the memory 41 or to process data, such as executing computer-readable instructions for the dead-time compensation method.

[0082] The network interface 43 may include a wireless network interface or a wired network interface, which is typically used to establish communication connections between the computer device 4 and other electronic devices.

[0083] This embodiment provides a computer device that uses a dead-zone compensation method, including: acquiring modulation control data from multiple level converters; confirming a target dead-zone compensation algorithm based on the modulation control data; processing the modulation control data based on the target dead-zone compensation algorithm to obtain a target dead-zone compensation value; updating the harmonic state of the multiple level converters based on the target dead-zone compensation value; and determining whether the positive and negative modulation waves need dead-zone compensation and the compensation direction by judging the current charging and discharging direction and whether the positive and negative modulation waves overlap based on the capacitor voltage, inverter side current reference value, and original modulation wave, thereby effectively reducing the 6th harmonic caused by the dead zone.

[0084] This application also provides another embodiment, namely, providing a computer-readable storage medium storing computer-readable instructions that can be executed by at least one processor to cause the at least one processor to perform the steps of the dead-zone compensation method described above.

[0085] This embodiment provides a computer-readable storage medium that uses a dead-zone compensation method, including: acquiring modulation control data from multiple level converters; confirming a target dead-zone compensation algorithm based on the modulation control data; processing the modulation control data based on the target dead-zone compensation algorithm to obtain a target dead-zone compensation value; updating the harmonic state of the multiple level converters based on the target dead-zone compensation value; and determining whether the positive and negative modulation waves need dead-zone compensation and the compensation direction by judging the current charging and discharging direction and whether the positive and negative modulation waves overlap based on the capacitor voltage, inverter side current reference value, and original modulation wave, thereby effectively reducing the 6th harmonic caused by the dead zone.

[0086] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0087] Obviously, the embodiments described above are only some embodiments of this application, not all embodiments. The accompanying drawings show preferred embodiments of this application, but do not limit the patent scope of this application. This application can be implemented in many different forms; rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this application's specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the scope of patent protection of this application.

Claims

1. A dead-time compensation method applied to a level converter, characterized in that, Includes the following steps: Acquire modulation control data from multiple level converters; The target dead zone compensation algorithm is confirmed based on the modulation control data; The modulation control data is processed based on the target dead zone compensation algorithm to obtain the target dead zone compensation value; The harmonic states of the plurality of level converters are updated based on the target dead zone compensation value; The step of acquiring the modulation control data of the level converter specifically includes: Collect capacitor voltage data, raw modulation wave signals, and inverter-side current reference values ​​from multiple level converters to serve as modulation control data for the level converters. The steps of confirming the target dead zone compensation algorithm based on the modulation control data specifically include: Based on the capacitor voltage data and the original modulation wave signal, the target compensation direction is determined, which includes the positive modulation wave compensation direction and the negative modulation wave compensation direction. Based on the target compensation direction, a target dead zone compensation algorithm is determined from a preset dead zone compensation algorithm, wherein the positive modulation wave compensation direction corresponds to the first target dead zone compensation algorithm and the negative modulation wave compensation direction corresponds to the second target dead zone compensation algorithm. The first target dead zone compensation algorithm is expressed as follows: Wherein, M+ is the positive modulation wave after dead-zone compensation, and d dt The dead zone duty cycle, i ref As a current reference value, the I th The current threshold; When the current reference value is greater than the threshold I th At this time, a compensation amount is added to the positive modulation wave to increase the duty cycle; When the current reference value is less than -I th When the positive modulation wave is reduced, the compensation amount is decreased to lower the duty cycle; when the current reference value is located at [-I th， I th When the reference current value is within the range of [-Ith, Ith], no compensation is performed, and the original signal is output directly. Specifically, when the reference current value is within the range of [-Ith, Ith], it is determined that dead-zone compensation processing is not performed under the current zero-crossing or positive and negative modulation wave overlap conditions, so as to suppress invalid dead-zone compensation generated under the current zero-crossing or positive and negative modulation wave overlap conditions. The second target dead zone compensation algorithm is expressed as follows: Wherein, M- is the negative modulation wave after dead-zone compensation, and d dt It is the dead zone duty cycle, i ref It is the current reference value, the I th It is the current threshold; The step of determining the target compensation direction based on the capacitor voltage data and the original modulated wave signal further includes: When the capacitor voltage data is less than zero, the target compensation direction is determined to be the negative modulation wave compensation direction, or When the capacitor voltage data is greater than zero and the original negative modulation wave is less than one, the target compensation direction is determined to be the negative modulation wave compensation direction. When the capacitor voltage data is greater than zero, the target compensation direction is determined to be the positive modulation wave compensation direction, or When the capacitor voltage data is less than zero and the original positive modulation wave is greater than zero, the target compensation direction is determined to be the positive modulation wave compensation direction. The step of compensating the plurality of level converters based on the target dead-zone compensation value and updating the harmonic state of the level converters specifically includes: Obtain the overlapping region of positive and negative modulation waves in the plurality of level converters; Based on the positive and negative modulation compensation data, synchronous compensation processing is performed on the overlapping region of the positive and negative modulation waves to update the harmonic state of the multiple level converters. The steps of the synchronization compensation process specifically include: Invoke the first target dead zone compensation algorithm and the second target dead zone compensation algorithm; Based on the first target dead zone compensation algorithm and the second target dead zone compensation algorithm, the positive adjustment compensation data and the negative adjustment compensation data are calculated in parallel with the same sampling period and time window and synchronously written into the converter control module. The positive modulation wave and the negative modulation wave are compensated and corrected at the same time.

2. The dead zone compensation method according to claim 1, characterized in that, The target dead-zone compensation value includes positive modulation compensation data and negative modulation compensation data. The step of processing the modulation control data based on the target dead-zone compensation algorithm to obtain the target dead-zone compensation value specifically includes: When the target compensation direction is the positive modulation wave compensation direction, the modulation control data is compensated for the first dead zone based on the first target dead zone compensation algorithm to obtain the positive modulation compensation data. When the target compensation direction is the negative modulation wave compensation direction, the modulation control data is subjected to a second compensation process based on the second target dead zone compensation algorithm to obtain the negative modulation compensation data.

3. The dead zone compensation method according to claim 1, characterized in that, The step of determining the target compensation direction based on the capacitor voltage data and the original modulated wave signal specifically includes: When the capacitor voltage data is greater than zero, the target compensation direction is determined to be the positive modulation wave compensation direction, or When the capacitor voltage data is less than zero and the original positive modulation wave is greater than zero, the target compensation direction is determined to be the positive modulation wave compensation direction.

4. A dead-time compensation device, applied to a level converter, characterized in that, When the dead zone compensation device is executed, it implements the steps of the dead zone compensation method as described in any one of claims 1 to 3, including: The acquisition module is used to acquire modulation control data from multiple level converters; The confirmation module is used to confirm the target dead zone compensation algorithm based on the modulation control data; The processing module is used to process the modulation control data based on the target dead zone compensation algorithm to obtain the target dead zone compensation value; An update module is used to update the harmonic state of the level converter based on the target dead zone compensation value.

5. A computer device, characterized in that, The device includes a memory and a processor, wherein the memory stores computer-readable instructions, and the processor executes the computer-readable instructions to implement the steps of the dead-zone compensation method as described in any one of claims 1 to 3.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-readable instructions, which, when executed by a processor, implement the steps of the dead-zone compensation method as described in any one of claims 1 to 3.

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