Control method of grid-connected converter, photovoltaic grid-connected circuit and traction power supply system

Abstract

The invention provides a control method of a grid-connected converter, a photovoltaic grid-connected circuit and a railway traction power supply system. The control method comprises the following steps: determining a voltage component of a grid-connected voltage under a rotating coordinate and a current component of a grid-connected current under the rotating coordinate; inputting the deviation between the direct-current side reference voltage and the actual direct-current voltage into a self-adaptive sliding mode controller, and determining an output active current reference; inputting a deviation between the current reference and the current component in a first current controller, and inputting a deviation between the current reference and the actual current component in a second current controller; items are introduced into the output of the first current controller and the output of the second current controller respectively, decoupling control is carried out on grid-connected current under a rotating coordinate system, and control signals on axes are determined; and carrying out inverse transformation on the on-axis control signal and the on-axis control signal to generate a PWM driving signal.

Description

Technical Field

[0001] This application relates to the field of AC electrified railway traction power supply, and in particular to a control method for a grid-connected converter, a photovoltaic grid-connected circuit, and a railway traction power supply system. Background Technology

[0002] Currently, railway traction power supply systems typically use a single-phase power supply system. Therefore, photovoltaic energy storage systems need to be connected to the grid via a single-phase grid-connected converter (GCC).

[0003] Due to the fluctuations and uncertainties in the power output of photovoltaic-storage systems, the stability of the DC bus voltage is poor. A single-phase grid-connected converter can be used to control the DC bus voltage. Among related technologies, the DC voltage control of the single-phase grid-connected converter can achieve relative stability of the DC bus voltage using dual closed-loop control.

[0004] However, the inventors of this application accidentally discovered during their research that, in a single-phase power supply system, the controller used in the dual closed-loop control cannot meet the stability requirements of the DC bus voltage for photovoltaic energy storage systems connected to a single-phase power supply system. Summary of the Invention

[0005] This application provides a control method for a grid-connected converter, a photovoltaic grid-connected circuit, and a railway traction power supply system to solve the problem that the DC bus voltage of the grid-connected converter in the current photovoltaic-storage system cannot be quickly stabilized.

[0006] To solve the above-mentioned technical problems, this application is implemented as follows: Firstly, a control method for a grid-connected converter is provided, the control method comprising: Determine the grid connection voltage exist Voltage components in rotating coordinates , and grid-connected current exist Current components in rotating coordinates , ; DC side reference voltage and actual DC voltage The deviation is input to the adaptive sliding mode controller. Determine the reference output active current. ; First current controller Input the current reference With the current component The deviation in the second current controller Input current reference With the actual current component Deviation; For the first current controller The output of the second current controller The outputs in are respectively introduced into The project, for Decoupling control of grid-connected current in a rotating coordinate system, determined in shaft and Control signals for the shaft; The above shaft and The control signal of the shaft passes through After inverse transformation, a PWM drive signal is generated. .

[0007] In one alternative implementation, the DC-side reference voltage is... and actual DC voltage The deviation is input to the sliding controller. Determine the reference output active current. Including: The actual DC voltage After passing through the notch filter bank, the actual DC voltage after multiple filtering is obtained. ; The DC side reference voltage and the actual DC voltage after multiple filtering The deviation is input to the sliding controller. .

[0008] In one alternative implementation, the notch filter bank includes at least two sets of filters corresponding to different frequencies.

[0009] In one optional embodiment, the notch filter bank includes at least one of the following: a 100Hz notch filter, a 200Hz notch filter, and a 300Hz notch filter.

[0010] In one alternative implementation, the grid-connected current We obtain the following formula: , Where P is the grid-connected power; k2, k3, and α are all positive real numbers, k2 is the sliding coefficient, k3 is the switching gain, and α is a constant. It is the exponential-power approach law, and its expression is: .

[0011] In one alternative implementation, the determination of the grid connection voltage... exist Voltage components in rotating coordinates , and grid-connected current exist Current components in rotating coordinates , ,include: Grid-connected voltage Grid-connected current Input SOGI (Second-Order Generalized Integrator) to obtain the grid-connected voltage. Grid-connected current exist Voltage components in coordinate system , and current components , ; Phase provided by phase-locked loop (PLL) ,Will Voltage components in coordinate system , and current components , Transform to In the rotating coordinate system, the grid-connected voltage is obtained. exist Voltage components in rotating coordinates , and grid-connected current exist Current components in rotating coordinates , .

[0012] In an optional implementation, the method further includes: Validating the adaptive sliding mode controller Stability.

[0013] Secondly, a control device for a grid-connected converter is provided, the control device comprising: Component determination module, used to determine grid-connected voltage exist Voltage components in rotating coordinates , and grid-connected current exist Current components in rotating coordinates , ; The sliding mode control input module is used to input the DC side reference voltage. and actual DC voltage The deviation is input to the adaptive sliding mode controller. Determine the reference output active current. ; Current control input module, used in the first current controller Input the current reference With the current component The deviation in the second current controller Input current reference With the actual current component Deviation; Decoupling module, used for the first current controller The output of the second current controller The outputs in are respectively introduced into The project, for Decoupling control of grid-connected current in a rotating coordinate system, determined in shaft and Control signals for the shaft; The generation module is used to generate the... shaft and The control signal of the shaft passes through After inverse transformation, a PWM drive signal is generated. .

[0014] Thirdly, a photovoltaic grid-connected circuit is provided, the grid-connected circuit including a photovoltaic energy storage system, an LC filter and a single-phase grid-connected converter system, wherein the LC filter is connected between the photovoltaic energy storage system and the single-phase grid-connected converter module: The LC filter includes a second inductor and a second capacitor connected in series; The single-phase grid-connected converter system is used to invert DC-side electrical energy into AC power and connect it to the power grid. The single-phase grid-connected converter system includes a converter and multiple switching devices forming a full-bridge topology. The bases of the multiple switching devices are connected to the PWM drive signal as described in any of the preceding claims. ; The photovoltaic-storage system includes an energy storage module and a photovoltaic panel module. The two ends of the energy storage module and the two ends of the photovoltaic panel module are respectively connected to the two ends of the LC filter.

[0015] Fourthly, a railway traction power supply system is provided, including the photovoltaic grid-connected circuit described above.

[0016] This application provides a control method for a grid-connected converter. Compared to related technologies that use a proportional-integral (PI) controller in dual closed-loop control, this application employs a sliding mode controller. DC side reference voltage and actual DC voltage The deviation is input to the adaptive sliding mode controller. Determine the reference output active current. Due to the synovial controller Enables the DC voltage of each grid-connected converter By maintaining stability, and thus ensuring that the DC bus voltage input to the railway traction power supply system quickly stabilizes, the problem of not being able to meet stability requirements when using related technologies is solved. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in one or more embodiments of this specification, the accompanying drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a block diagram of a single-phase grid-connected converter control system based on dual closed-loop control in related technologies. Figure 2 A control method for a grid-connected converter provided in the embodiments of this application; Figure 3 A control system block diagram based on a grid-connected converter is provided for an embodiment of this application; Figure 4 For the purposes of this application's embodiments Figure 2 Simulation waveforms used to verify the control method; Figure 5 This application provides a circuit topology for a grid-connected system of single-phase photovoltaic energy storage. Figure 6 This is a schematic diagram illustrating the distributed integration of a photovoltaic energy storage system into a railway traction power supply system, as described in this application embodiment. Figure 7 A schematic diagram of the control device for a grid-connected converter provided in the application embodiment; Figure 8 A schematic diagram of the hardware structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the following will clearly and completely describe the technical solutions in one or more embodiments of this specification in conjunction with the accompanying drawings in one or more embodiments of this specification. Obviously, the described embodiments are only a part of the embodiments of this specification, rather than all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this document.

[0020] Refer Figure 1 , which is a control system block diagram of a single-phase grid-connected inverter based on double closed-loop control in the related art.

[0021] From Figure 1 the upper half, it can be seen that the grid-connected voltage and grid-connected current are first input into a Second-Order Generalized Integrator (SOGI) to obtain the voltage components and current components of the grid-connected voltage and grid-connected current , in the , coordinate system; then, using the phase provided by the Phase-Locked Loop (PLL), the voltage components and current components , in the , coordinate system are transformed to the rotating coordinate system to obtain the voltage components and current components of the grid-connected voltage , in the rotating coordinate and the current components and ,[[ID=​​​​​​​​​​​​​​​​ Then, in the first current controller Input the current reference With the current component The deviation in the second current controller Input current reference With the actual current component The deviation; for the first current controller The output of the second current controller The outputs in are respectively introduced into project( It is the angular frequency of the power grid. It is a grid-connected inductor), for Decoupling control of grid-connected current in a rotating coordinate system, determined in shaft and The control signal of the axis; will be in shaft and The control signal of the shaft passes through After the inverse transformation, a pulse-width modulation (PWM) drive signal is generated. Therefore, based on this PWM drive signal Control the switching devices in the grid-connected converter system. Figure 1 The system block diagram controls the switching devices in the grid-connected converter system through a process of "signal detection - coordinate transformation - dual closed-loop decoupling control - PWM drive".

[0023] Adopting such Figure 1 When using a control system block diagram to control the switching devices in a grid-connected converter system, there is a phenomenon where the control effect is poor when the load changes, leading to a decrease in the stability of the DC bus voltage. After a series of studies, the inventors of this application found that this is caused by the large static error of the PI controller used in the dual closed-loop control.

[0024] To address the aforementioned problems, one or more embodiments of a control method for a grid-connected converter provided in this application are as follows: Reference Figure 2 This illustrates a control method for a grid-connected converter provided in an embodiment of this application, which may include the following steps S101 to S105, corresponding to... Figure 3 The document provides a block diagram of a single-phase grid-connected converter control system according to an embodiment of this application.

[0025] Step S101: Determine the grid connection voltage exist Voltage components in rotating coordinates , and grid-connected current exist Current components in rotating coordinates , .

[0026] Step S102, set the DC side reference voltage and actual DC voltage The deviation is input to the adaptive sliding mode controller. Determine the reference output active current. .

[0027] Step S103, in the first current controller Input current reference With current component The deviation in the second current controller Input current reference With actual current component The deviation.

[0028] Step S104, for the first current controller The output and second current controller in The outputs in are respectively introduced into The project, for Decoupling control of grid-connected current in a rotating coordinate system, determined in shaft and The control signal of the axis can then control the axis. shaft and The axes are controlled relatively independently, improving control accuracy and dynamic response.

[0029] Step S105 will be shaft and The control signal of the shaft passes through After inverse transformation, a PWM drive signal is generated. Used to realize the grid-connected current and DC voltage Precise control.

[0030] Compared to the use of PI controllers in dual closed-loop control in related technologies, this application uses a sliding mode controller. DC side reference voltage and actual DC voltage The deviation is input to the adaptive sliding mode controller. Determine the reference output active current. Due to the synovial controller Enables the DC voltage of the grid-connected converter By maintaining stability, and thus ensuring that the DC bus voltage input to the railway traction power supply system quickly stabilizes, the problem of not being able to meet the stability requirements when using related dual closed-loop control is solved.

[0031] In one embodiment, step S102 includes steps S1021 and S1022.

[0032] Step S1021, Actual DC Voltage After passing through the notch filter bank, the actual DC voltage after multiple filtering is obtained. .

[0033] Step S1022, set the DC side reference voltage and the actual DC voltage after multiple filtering The deviation is input to the sliding controller. . The inventors of this application also discovered in their research that the use of dual closed-loop control cannot avoid the inherent second harmonic current problem of single-phase grid-connected converters. Therefore, in step S1021, the actual DC voltage... After passing through the notch filter bank, the second harmonic current can be effectively controlled, thereby suppressing low-order harmonics of different frequencies in the AC side current.

[0034] In one embodiment, step S101 includes steps S1011 and S1012.

[0035] Step S1011, the grid-connected voltage Grid-connected current Input a second-order generalized integrator (SOGI) to obtain the grid-connected voltage. Grid-connected current exist Voltage components in coordinate system , and current components , The SOGI function is to extract the fundamental components of the grid-connected voltage and current, while simultaneously tracking the phase and amplitude, providing a clean input signal for subsequent control.

[0036] Step S1012, using the phase provided by the phase-locked loop (PLL) ,Will Voltage components in coordinate system , and current components , Transform to In the rotating coordinate system, the grid-connected voltage is obtained. exist Voltage components in rotating coordinates , and grid-connected current exist Current components in rotating coordinates , .

[0037] in, The rotation speed of the rotating coordinate system can be synchronized with the grid connection frequency to facilitate the conversion of AC quantities into DC quantities for control.

[0038] The notch filter bank may include at least two sets of filters corresponding to different frequencies.

[0039] In one embodiment, the notch filter bank includes at least one of the following: a 100Hz notch filter, a 200Hz notch filter, and a 300Hz notch filter. This allows for the filtering out of low-order harmonics on the DC side (which are typically introduced by the grid or inverter characteristics) before the signal enters the adaptive sliding mode controller. Of course, the notch filter bank can also include notch filters of other frequencies, such as 400Hz notch filters, 500Hz notch filters, 600Hz notch filters, etc.

[0040] In one implementation, the method further includes: verifying the adaptive sliding mode controller. Stability.

[0041] In one implementation, Figure 3 In the system control block diagram, the DC side reference voltage It can be a manually set value, current reference. It can take the value 0.

[0042] In one embodiment of this application, a multiplied notch filter can be selected to suppress second, fourth, and sixth harmonic pulsations in the DC voltage.

[0043] The s-domain mathematical model of the notch filter is as follows: (1) In the above formula, It is a complex variable in the Laplace transform, and NF is the notch filter. It is the transfer function of the notch filter. Here, is the notch angular frequency, and parameter A is the open-loop gain of the adjustable filter. This is the equivalent quality factor.

[0044] Set the notch angle frequency = 2π*100 rad / s, A = 1. The notch filter in... The corresponding frequency amplitude shows a significant attenuation, with minimal impact on other frequencies. The smaller the value of Q, the higher the frequency... A larger amplitude attenuation will provide a better filtering effect and a wider bandwidth, which is beneficial for parameter tolerance (frequency deviation). However, an excessively small Q value will cause frequency deviation. Phase variations over a relatively wide frequency range may cause the voltage loop to lose a significant stability margin. When the Q value is small, the phase-frequency characteristic changes of the voltage loop introduced by the filter will be more pronounced, and the filter parameter tuning must consider both the controlled object and the controller parameters. Conversely, appropriately increasing the Q value will reduce the filter's impact on stability. The influence of amplitude and phase frequency characteristics in the nearby frequency range will be greatly reduced, so this application can set a larger Q value, setting Q = 10.

[0045] In addition to second-harmonic pulsations, DC voltage may also contain even-harmonic pulsations such as fourth-harmonic and sixth-harmonic pulsations due to control reasons. Multiple notch filters with different notch frequencies can be introduced into the DC voltage feedback branch to form a multi-stage notch filter. For this purpose, three notch filter units with notch frequencies of 100, 200, and 300 Hz can be cascaded in the DC voltage feedback branch.

[0046] Regarding the aforementioned adaptive sliding mode controller, the DC voltage error and its integral are first selected to form the sliding surface for the DC voltage outer loop control.

[0047] Specifically, the DC voltage tracking error is defined as: (2) The sliding surface is constructed by selecting the DC voltage error and its integral, and its expression is as follows: (3) Where k1 is the sliding surface coefficient and is a positive real number. Taking the first differential of equation (3) yields: (4) in, It is a DC bus capacitor.

[0048] Next, the outer loop of the DC voltage is set to use an exponential-power approach rate to form an adaptive sliding mode control, which can reduce system chattering while ensuring rapid approach.

[0049] The expression for this exponential-power approximation rate is: (5) Combining equations (4) and (5), the reference amplitude of the grid-connected current can be obtained as follows: (6) Where k2, k3, and α are all positive real numbers, k2 is the sliding coefficient, k3 is the switching gain, and α is a constant.

[0050] The proposed exponential-power-law approach combines the advantages of both exponential and power-law approaches, and can adaptively adjust the convergence speed of the system. (Exponential term) Can guarantee when When the power term is large, the system can approach the sliding mode at a greater speed, thus enabling it to handle response control problems with large step changes. The power term is set by... A value of 0.5 ensures that the system approaches the sliding mode at a higher speed when the system state is far from the sliding surface, and approaches the sliding mode at a lower speed when the system state approaches the sliding surface, thus reducing chattering. Therefore, the adaptive sliding mode control proposed in this invention can reduce system chattering while ensuring rapid approach.

[0051] The exponential-power approximation rate expression is existing technology and will not be elaborated upon in this application.

[0052] In one embodiment, the stability of the proposed adaptive sliding mode controller is also verified, and if the stability does not meet the preset conditions, the adaptive module controller is adjusted.

[0053] To ensure the stability of the proposed adaptive sliding mode controller, the following Lyapunov function is selected: (7) Taking the first derivative of equation (7) yields: (8) Since k2 and k3 are both positive real numbers, equation (8) ≤ 0 always holds true, and the proposed single-phase grid-connected converter based on adaptive sliding mode controller is stable.

[0054] In one implementation, the effectiveness of the control method is also verified. A simulation model is built on the Matlab / Simulink simulation platform for verification, and the results are as follows: Figure 4 The simulated waveform is shown. Figure 4 The operating conditions are set as follows: the transmission power P (MW) suddenly changes from 1MW to 0.6MW and then suddenly changes to 0.8MW. It can be seen that the DC bus voltage U... dc (V) The control is stable and responds quickly under high power sudden change conditions, which proves that the control method has high control accuracy and robustness while ensuring DC voltage stability. It can provide a constant DC bus voltage for photovoltaic energy storage system to be connected to the railway 25kV single-phase power supply system.

[0055] The control method in this application embodiment is based on dual closed-loop control. A notch filter bank (multiplexed notch filter) is introduced in the DC voltage feedback branch to manage the second harmonic current, thereby suppressing low-order harmonics of different frequencies in the AC side current. Adaptive sliding mode control is used in the DC voltage outer loop, which can reduce system chattering while ensuring rapid approach. This control method ensures the DC voltage... Based on stability, it has high control precision and robustness, and can provide a constant DC bus voltage for photovoltaic energy storage systems to be connected to the railway 25kV single-phase power supply system.

[0056] In this embodiment, a method for stabilizing the DC voltage of a single-phase photovoltaic-storage grid-connected converter for railway applications is implemented using a multiplexed notch filter and adaptive sliding mode control. This control method ensures stable DC voltage. Based on stability, it has high control accuracy and robustness, providing a constant DC bus voltage for the photovoltaic-storage system to be connected to the railway 25kV single-phase power supply system.

[0057] This application embodiment also provides a photovoltaic grid-connected circuit, which includes a photovoltaic-storage system, an LC filter, and a single-phase grid-connected converter system. An inductor-capacitor (LC) filter is connected between the photovoltaic-storage system and the single-phase grid-connected converter module. The LC filter includes a second inductor and a second capacitor connected in series. The single-phase grid-connected converter system is used to invert DC-side power into AC power and connect it to the grid. The single-phase grid-connected converter system includes a converter and multiple switching devices forming a full-bridge topology. The bases of the multiple switching devices are connected to... Figure 3 PWM drive signal in The photovoltaic-storage system includes an energy storage module and a photovoltaic panel module. The two ends of the energy storage module and the two ends of the photovoltaic panel module are respectively connected to the two ends of the LC filter.

[0058] The circuit topology of the grid-connected system for this single-phase photovoltaic energy storage can be referenced. Figure 5 The single-phase grid-connected converter adopts a two-level structure and a large capacitor. To support the DC bus. LC filters are used to filter out second harmonic currents. The photovoltaic modules of this photovoltaic-storage system can use boost converters to achieve MPPT control, in order to capture the maximum amount of solar energy from the photovoltaic array; the DC-DC converter of the energy storage module can use single-current-loop control to achieve tracking of target power commands. The single-phase grid-connected converter can also use a three-level structure. In a grid-connected converter with a DC bus voltage of 1200V and a capacity of 1MW, a large capacitor... The value is approximately 8000-10000μF.

[0059] exist Figure 5In this context, PV stands for photovoltaic, ESS stands for energy storage, and GCC stands for grid-connected converter. It is the grid-connected current, connected to the PWM drive signal. , It is direct current. It is DC voltage. It is a DC capacitor. and It belongs to a secondary ripple filter. It is the output current on the high-voltage side of the photovoltaic system. It is the output current on the high-voltage side of the energy storage system. It is the high-voltage side capacitor of the photovoltaic system. It is the high-voltage side capacitor of the energy storage system. It is the switching signal of the photovoltaic system. It is a switching signal for the energy storage system. It is a filter inductor for photovoltaic systems. It is a filter inductor for the energy storage system. It is the low-voltage side capacitor of the photovoltaic system. It is the low-voltage side capacitor of the energy storage system. It is the inductor current of the photovoltaic system. It is the inductor current of the energy storage system. and These are the output current and voltage of the photovoltaic array, respectively. and These are the output current and voltage of the battery module, respectively.

[0060] The single-phase grid-connected converter adopts a two-level structure and can use the Insulated-Gate Bipolar Transistor Parallel Connection Mode (IGBT). The input side does not require a current-sharing reactor, reducing the number of power devices used. Moreover, the two-level control strategy does not have problems such as bus voltage equalization control.

[0061] This application also provides a railway traction power supply system, which includes the photovoltaic grid-connected circuit described in the above embodiments. (See reference...) Figure 6 This is a schematic diagram illustrating the distributed integration of a photovoltaic and energy storage system into the railway's AC 25kV traction power supply system. Figure 6 The single-phase grid-connected converter shown can be the grid-connected converter in the photovoltaic grid-connected circuit in the above embodiments.

[0062] This application also provides a control device for a grid-connected converter. This device can execute the control steps of the grid-connected converter described above and can be applied to photovoltaic grid-connected circuits or electronic equipment. Figure 7 The control device 70 of the grid-connected converter includes: Component determination module 71 is used to determine the grid-connected voltage. exist Voltage components in rotating coordinates , and grid-connected current exist Current components in rotating coordinates , .

[0063] Sliding mode control input module 72 is used to input the DC side reference voltage. and actual DC voltage The deviation is input to the adaptive sliding mode controller. Determine the reference output active current. .

[0064] Current control input module 73, used in the first current controller Input the current reference With the current component The deviation in the second current controller Input current reference With the actual current component The deviation.

[0065] Decoupling module 74 is used for the first current controller The output of the second current controller The outputs in are respectively introduced into The project, for Decoupling control of grid-connected current in a rotating coordinate system, determined in shaft and Control signals for the shaft.

[0066] Generation module 75, used to generate the... shaft and The control signal of the shaft passes through After inverse transformation, a PWM drive signal is generated. .

[0067] In one embodiment, the DC-side reference voltage and actual DC voltage The deviation is input to the sliding controller. Determine the reference output active current. Including: The actual DC voltage After passing through the notch filter bank, the actual DC voltage after multiple filtering is obtained. ; The DC side reference voltage and the actual DC voltage after multiple filtering The deviation is input to the sliding controller. .

[0068] In one embodiment, the notch filter bank includes at least two sets of filters corresponding to different frequencies.

[0069] In one embodiment, the notch filter bank includes at least one of the following: a 100Hz notch filter, a 200Hz notch filter, and a 300Hz notch filter.

[0070] In one implementation, the grid-connected current We obtain the following formula: , Where P is the grid-connected power; k2, k3, and α are all positive real numbers, k2 is the sliding coefficient, k3 is the switching gain, and α is a constant. It is the exponential-power approach law, and its expression is: .

[0071] In one implementation, the determination of the grid-connected voltage exist Voltage components in rotating coordinates , and grid-connected current exist Current components in rotating coordinates , ,include: Grid-connected voltage Grid-connected current Input SOGI (Second-Order Generalized Integrator) to obtain the grid-connected voltage. Grid-connected current exist Voltage components in coordinate system , and current components , ; Phase provided by phase-locked loop (PLL) ,Will Voltage components in coordinate system , and current components , Transform to In the rotating coordinate system, the grid-connected voltage is obtained. exist Voltage components in rotating coordinates , and grid-connected current exist Current components in rotating coordinates , .

[0072] In one embodiment, the device is also used to verify the adaptive sliding mode controller. Stability.

[0073] The control device for the grid converter provided in this application embodiment can execute the methods described in the preceding method embodiments and realize the functions and beneficial effects of the methods described in the preceding method embodiments, which will not be repeated here.

[0074] Figure 8 The diagram illustrates the hardware structure of an electronic device implementing the embodiments of this application. Referring to the diagram, at the hardware level, the electronic device includes a processor and optionally, an internal bus, a network interface, and a memory. The memory may include RAM, such as high-speed random-access memory (RAM), or non-volatile memory, such as at least one disk storage device. Of course, the electronic device may also include other hardware required for other services.

[0075] The processor, network interface, and memory can be interconnected via an internal bus, which can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. This bus can be categorized as an address bus, data bus, control bus, etc. For ease of illustration, only a single bidirectional arrow is used in this diagram, but this does not imply that there is only one bus or one type of bus.

[0076] Memory is used to store programs. Specifically, programs may include program code, which includes computer operation instructions. Memory may include main memory and non-volatile memory, and provides instructions and data to the processor.

[0077] The processor reads the corresponding computer program from non-volatile memory into main memory and then executes it, forming a device at the logical level that locates the target user. The processor executes the program stored in memory and specifically performs the following: Figure 2The methods disclosed in the embodiments shown achieve the functions and beneficial effects of the methods described in the preceding method embodiments, and will not be repeated here.

[0078] The above is as stated in this application. Figure 2 The methods disclosed in the illustrated embodiments can be applied to or implemented by a processor. The processor may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above methods can be completed by integrated logic circuits in the processor's hardware or by instructions in software form. The processor can be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software module can reside in a mature storage medium in the field, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method.

[0079] The electronic device can also execute the methods described in the preceding method embodiments and achieve the functions and beneficial effects of the methods described in the preceding method embodiments, which will not be repeated here.

[0080] Of course, in addition to software implementation, the electronic device of this application does not exclude other implementation methods, such as logic devices or a combination of hardware and software, etc. In other words, the execution subject of the following processing flow is not limited to each logic unit, but can also be hardware or logic devices.

[0081] This application also proposes a computer-readable storage medium that stores one or more programs, which, when executed by an electronic device including multiple applications, cause the electronic device to perform... Figure 2The methods disclosed in the embodiments shown achieve the functions and beneficial effects of the methods described in the preceding method embodiments, and will not be repeated here.

[0082] The computer-readable storage medium mentioned above includes read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk, etc.

[0083] Furthermore, embodiments of this application also provide a computer program product, the computer program product including a computer program stored on a non-transitory computer-readable storage medium, the computer program including program instructions, which, when executed by a computer, implement the following process: Figure 2 The methods disclosed in the embodiments shown achieve the functions and beneficial effects of the methods described in the preceding method embodiments, and will not be repeated here.

[0084] In summary, the above description is merely a preferred embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

[0085] The systems, devices, modules, or units described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer. Specifically, a computer can be, for example, a personal computer, laptop computer, cellular phone, camera phone, smartphone, personal digital assistant, media player, navigation device, email device, game console, tablet computer, wearable device, or any combination of these devices.

[0086] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0087] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0088] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

Claims

1. A control method for a grid-connected converter, characterized in that, The control method includes: Determine the grid connection voltage exist Voltage components in rotating coordinates , and grid-connected current exist Current components in rotating coordinates , ; DC side reference voltage and actual DC voltage The deviation is input to the adaptive sliding mode controller. Determine the reference output active current. ; First current controller Input the current reference With the current component The deviation in the second current controller Input current reference With the actual current component Deviation; For the first current controller The output of the second current controller The outputs in are respectively introduced into The project, for Decoupling control of grid-connected current in a rotating coordinate system, determined in shaft and Control signals for the shaft; The above shaft and The control signal of the shaft passes through After inverse transformation, a pulse width modulation (PWM) drive signal is generated. .

2. The method according to claim 1, characterized in that, The DC side reference voltage and actual DC voltage The deviation is input to the sliding controller. Determine the reference output active current. Including: The actual DC voltage After passing through the notch filter bank, the actual DC voltage after multiple filtering is obtained. ; The DC side reference voltage and the actual DC voltage after multiple filtering The deviation is input to the sliding controller. .

3. The method according to claim 2, characterized in that, The notch filter bank includes at least two sets of filters corresponding to different frequencies.

4. The method according to claim 2, characterized in that, The notch filter bank includes at least one of the following: a 100Hz notch filter, a 200Hz notch filter, and a 300Hz notch filter.

5. The method according to claim 1, characterized in that, The grid-connected current We obtain the following formula: ， Where P is the grid-connected power, k2, k3, and α are all positive real numbers, k2 is the sliding coefficient, k3 is the switching gain, and α is a constant; It is the exponential-power approach law, and its expression is: .

6. The method according to claim 1, characterized in that, The determination of grid connection voltage exist Voltage components in rotating coordinates , and grid-connected current exist Current components in rotating coordinates , ,include: Grid-connected voltage Grid-connected current Input the second-order generalized integrator SOGI to obtain the grid-connected voltage. Grid-connected current exist Voltage components in coordinate system , and current components , ; Phase provided by phase-locked loop (PLL) ,Will Voltage components in coordinate system , and current components , Transform to In the rotating coordinate system, the grid-connected voltage is obtained. exist Voltage components in rotating coordinates , and grid-connected current exist Current components in rotating coordinates , .

7. The control method according to claim 1, characterized in that, The method further includes: Validating the adaptive sliding mode controller Stability.

8. A control device for a grid-connected converter, characterized in that, The control device includes: Component determination module, used to determine grid-connected voltage exist Voltage components in rotating coordinates , and grid-connected current exist Current components in rotating coordinates , ; The sliding mode control input module is used to input the DC side reference voltage. and actual DC voltage The deviation is input to the adaptive sliding mode controller. Determine the reference output active current. ; Current control input module, used in the first current controller Input the current reference With the current component The deviation in the second current controller Input current reference With the actual current component Deviation; Decoupling module, used for the first current controller The output of the second current controller The outputs in are respectively introduced into The project, for Decoupling control of grid-connected current in a rotating coordinate system, determined in shaft and Control signals for the shaft; The generation module is used to generate the... shaft and The control signal of the shaft passes through After inverse transformation, a PWM drive signal is generated. .

9. A photovoltaic grid-connected circuit, characterized in that, The grid-connected circuit includes a photovoltaic-storage system, an inductor-capacitor (LC) filter, and a single-phase grid-connected converter system. The LC filter is connected between the photovoltaic-storage system and the single-phase grid-connected converter module. The LC filter includes a second inductor and a second capacitor connected in series; The single-phase grid-connected converter system is used to invert DC-side electrical energy into AC power and connect it to the power grid. The single-phase grid-connected converter system includes a converter and multiple switching devices forming a full-bridge topology. The bases of the multiple switching devices are connected to the PWM drive signal as described in any one of claims 1-8. ; The photovoltaic-storage system includes an energy storage module and a photovoltaic panel module. The two ends of the energy storage module and the two ends of the photovoltaic panel module are respectively connected to the two ends of the LC filter.

10. A railway traction power supply system, characterized in that, Includes the photovoltaic grid-connected circuit as described in claim 9.

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