Delay compensation method and device for improving dynamic performance of flexible direct current converter

Abstract

The invention relates to the technical field of flexible direct-current power transmission of a power system, in particular to a delay compensation method and device for improving dynamic performance of a flexible direct-current converter, and the method comprises the steps: collecting voltage and current signals of a grid-connected point, determining a phase angle used by Park transformation, and obtaining the voltage and current signals under a positive and negative sequence rotating coordinate system. And according to inner and outer ring control of the grid-forming flexible direct current converter, reference voltage under the positive and negative sequence rotating coordinate system is calculated. And determining a phase angle value after delay compensation, performing Park inverse transformation on the reference voltage under the rotating coordinate system based on the phase angle value, obtaining the reference voltage under the static coordinate system, and completing modulation. Therefore, the problem that the delay compensation method of the network-following type flexible direct-current converter depends on the phase-locked loop and is not suitable for the network-constructing type flexible direct-current converter without the phase-locked loop in the prior art is solved.

Description

Technical Field

[0001] The present application relates to the technical field of flexible direct current transmission of power systems, and in particular to a delay compensation method and device for improving the dynamic performance of a flexible direct current converter. Background Art

[0002] In high-voltage, large-capacity flexible DC transmission systems, due to factors such as the large number of modules and sub-modules and complex control links, the flexible DC converter inevitably has a long delay, which will lead to poor dynamic response capabilities of the system.

[0003] In the related art, the delay compensation method of the grid-following flexible DC converter relies on a phase-locked loop, which is not suitable for the grid-forming flexible DC converter without a phase-locked loop. Therefore, it is urgent to develop a delay compensation method and system suitable for the grid-forming flexible DC converter to improve the dynamic performance of the converter and enhance the stability of the new power system. Summary of the invention

[0004] The present application provides a delay compensation and device for improving the dynamic performance of a flexible DC converter, so as to solve the problem in the related art that the delay compensation method of a grid-following flexible DC converter relies on a phase-locked loop and is not suitable for a grid-forming flexible DC converter without a phase-locked loop.

[0005] The first aspect of the present application provides a delay compensation method for improving the dynamic performance of a flexible DC converter, comprising the following steps: collecting the grid-connected point voltage signal and current signal of the flexible DC converter in a stationary coordinate system, and determining the phase angle used for Park transformation to obtain the voltage signal and current signal in the positive and negative sequence rotating coordinate system, respectively; based on the voltage signal and the current signal, calculating the reference voltage in the positive and negative sequence rotating coordinate system according to the inner and outer loop control of the grid-type flexible DC converter; determining the phase angle value after delay compensation according to the delay of the flexible DC converter, and performing an inverse Park transformation on the reference voltage in the positive and negative sequence rotating coordinate system based on the phase angle value to obtain the reference voltage in the stationary coordinate system and perform modulation.

[0006] Through the above technical solution, the embodiment of the present application can effectively convert the signal into voltage and current signals in the positive and negative sequence rotating coordinate system by collecting the grid connection point voltage and current signals of the flexible DC converter and determining the corresponding Parker transformation phase angle. Then, based on the inner and outer loop control of the meshed flexible DC converter, the corresponding reference voltage is calculated, and the Parker inverse transformation is performed according to the phase angle value after delay compensation, so as to obtain the reference voltage in the stationary coordinate system and complete the modulation. This process optimizes the phase angle characteristics of the system, significantly improves the dynamic response performance and stability of the high-voltage and large-capacity flexible DC transmission system, and helps to better support the efficient transmission of new energy.

[0007] Optionally, in one embodiment of the present application, determining the phase angle used for the Parker transformation to obtain the voltage signal and the current signal in the positive and negative sequence rotating coordinate systems, respectively, includes: determining to generate a phase reference value according to the grid control strategy of the flexible DC converter, and using the phase reference value as the phase angle used for the Parker transformation; using the phase angle to perform a Parker transformation and positive and negative sequence decomposition on the grid connection point voltage signal and current signal in the stationary coordinate system, so as to obtain the voltage signal and current signal in the positive sequence rotating coordinate system and the voltage signal and current signal in the negative sequence rotating coordinate system, respectively.

[0008] Through the above technical solution, the embodiment of the present application can generate a phase reference value according to the grid control strategy of the flexible DC converter and use it as the phase angle of the Parker transformation, effectively performing Parker transformation and positive and negative sequence decomposition on the grid connection point voltage signal and current signal in the stationary coordinate system. This method not only improves the accuracy of signal processing, but also optimizes the dynamic response capability of the system.

[0009] Optionally, in one embodiment of the present application, the reference voltage in the positive and negative sequence rotating coordinate system is calculated based on the voltage signal and the current signal according to the inner and outer loop controls of the meshing type flexible DC converter, including: inputting the voltage signal, the current signal and the voltage amplitude reference value generated by the meshing control link into the inner and outer loop controllers of the flexible DC converter to obtain the reference voltage in the positive and negative sequence rotating coordinate system.

[0010] Through the above technical solution, the embodiment of the present application can input the voltage signal, current signal and voltage amplitude reference value generated by the network control link into the inner and outer loop controllers of the flexible DC converter, effectively integrating the real-time data and control strategy of the system, thereby accurately calculating the reference voltage in the positive and negative sequence rotating coordinate system. This technical solution improves the dynamic response capability of the converter and optimizes the control accuracy.

[0011] Optionally, in one embodiment of the present application, the reference voltages in the positive and negative sequence rotating coordinate systems are respectively:

[0012]

[0013]

[0014] Among them, G i is the transfer function of the PI link of the current inner loop of the flexible DC converter; is the positive sequence current reference value; i dqP is the current signal in the positive sequence rotating coordinate system; k d is the decoupling coefficient of the inner current loop; u dqP is the voltage signal in the positive sequence rotating coordinate system; i dqNis the current signal in the negative sequence rotating coordinate system; u dqN It is the voltage signal in the negative sequence rotating coordinate system.

[0015] Through the above technical solution, the calculation of the positive-sequence reference voltage and the negative-sequence reference voltage in the embodiment of the present application takes into account the feedback and regulation of the current signal, thereby improving the responsiveness of the converter to grid fluctuations.

[0016] Optionally, in one embodiment of the present application, the reference voltage in the positive and negative sequence rotating coordinate system is subjected to an inverse Park transformation based on the phase angle value to obtain a reference voltage in a stationary coordinate system and perform modulation, including: performing an inverse Park transformation on the reference voltage in the positive and negative rotating coordinate system based on the phase angle value to obtain an expression of the positive sequence reference voltage in the stationary coordinate system and an expression of the negative sequence reference voltage in the stationary coordinate system, respectively; adding the positive sequence reference voltage and the negative sequence reference voltage to obtain a total reference voltage; and calculating the modulation waves of the upper and lower bridge arms of the flexible DC converter according to the total reference voltage to determine the on and off control signals of the switching device.

[0017] Through the above technical solution, the embodiment of the present application can accurately obtain the expressions of the positive and negative sequence reference voltages in the stationary coordinate system by performing the Park inverse transformation on the reference voltages in the positive and negative rotating coordinate systems, and add them to obtain the total reference voltage. The control strategy of the flexible DC converter is optimized, making the calculation of the modulation wave more accurate, thereby improving the dynamic response performance and system stability of the converter, and meeting the needs of the high-voltage and large-capacity flexible DC transmission system.

[0018] The second aspect of the present application provides a delay compensation device for improving the dynamic performance of a flexible DC converter, including: an acquisition module, used to acquire the grid-connected point voltage signal and current signal of the flexible DC converter in a stationary coordinate system, and determine the phase angle used for Park transformation to obtain the voltage signal and current signal in the positive and negative sequence rotating coordinate system respectively; a calculation module, used to calculate the reference voltage in the positive and negative sequence rotating coordinate system based on the voltage signal and current signal according to the inner and outer loop control of the grid-type flexible DC converter; a compensation module, used to determine the phase angle value after delay compensation according to the delay of the flexible DC converter, and perform Park inverse transformation on the reference voltage in the positive and negative sequence rotating coordinate system based on the phase angle value to obtain the reference voltage in the stationary coordinate system and modulate it.

[0019] Through the above technical solution, the embodiment of the present application can effectively convert the signal into voltage and current signals in the positive and negative sequence rotating coordinate system by collecting the grid connection point voltage and current signals of the flexible DC converter and determining the corresponding Parker transformation phase angle. Then, based on the inner and outer loop control of the meshed flexible DC converter, the corresponding reference voltage is calculated, and the Parker inverse transformation is performed according to the phase angle value after delay compensation, so as to obtain the reference voltage in the stationary coordinate system and complete the modulation. This process optimizes the phase angle characteristics of the system, significantly improves the dynamic response performance and stability of the high-voltage and large-capacity flexible DC transmission system, and helps to better support the efficient transmission of new energy.

[0020] Optionally, in one embodiment of the present application, the acquisition module includes: a transformation unit, used to determine and generate a phase reference value according to the grid control strategy of the flexible DC converter, and use the phase reference value as the phase angle used for the Park transformation; a decomposition unit, used to use the phase angle to perform Park transformation and positive and negative sequence decomposition on the grid connection point voltage signal and current signal in the stationary coordinate system, so as to obtain the voltage signal and current signal in the positive sequence rotating coordinate system and the voltage signal and current signal in the negative sequence rotating coordinate system, respectively.

[0021] Through the above technical solution, the embodiment of the present application can generate a phase reference value according to the grid control strategy of the flexible DC converter and use it as the phase angle of the Parker transformation, effectively performing Parker transformation and positive and negative sequence decomposition on the grid connection point voltage signal and current signal in the stationary coordinate system. This method not only improves the accuracy of signal processing, but also optimizes the dynamic response capability of the system.

[0022] Optionally, in one embodiment of the present application, the calculation module includes: inputting the voltage signal, the current signal and the voltage amplitude reference value generated by the network control link into the inner and outer loop controllers of the flexible DC converter to obtain the reference voltage in the positive and negative sequence rotating coordinate system.

[0023] Through the above technical solution, the embodiment of the present application can input the voltage signal, current signal and voltage amplitude reference value generated by the network control link into the inner and outer loop controllers of the flexible DC converter, effectively integrating the real-time data and control strategy of the system, thereby accurately calculating the reference voltage in the positive and negative sequence rotating coordinate system. This technical solution improves the dynamic response capability of the converter and optimizes the control accuracy.

[0024] Optionally, in an embodiment of the present application, the calculation module includes: the reference voltages in the positive and negative sequence rotating coordinate systems are respectively:

[0025]

[0026]

[0027] Among them, G i is the transfer function of the PI link of the current inner loop of the flexible DC converter; is the positive sequence current reference value; i dqP is the current signal in the positive sequence rotating coordinate system; k d is the decoupling coefficient of the inner current loop; u dqP is the voltage signal in the positive sequence rotating coordinate system; i dqN is the current signal in the negative sequence rotating coordinate system; u dqN It is the voltage signal in the negative sequence rotating coordinate system.

[0028] Through the above technical solution, the calculation of the positive-sequence reference voltage and the negative-sequence reference voltage in the embodiment of the present application takes into account the feedback and regulation of the current signal, thereby improving the responsiveness of the converter to grid fluctuations.

[0029] Optionally, in one embodiment of the present application, the compensation module includes: an inverse transformation unit, used to perform a Park inverse transformation on the reference voltage in the positive and negative rotating coordinate systems based on the phase angle value, so as to obtain an expression of the positive-sequence reference voltage in the stationary coordinate system and an expression of the negative-sequence reference voltage in the stationary coordinate system, respectively; a summation unit, used to add the positive-sequence reference voltage and the negative-sequence reference voltage to obtain a total reference voltage; and a modulation unit, used to calculate the modulation waves of the upper and lower bridge arms of the flexible DC converter according to the total reference voltage, so as to determine the on and off control signals of the switching device.

[0030] Through the above technical solution, the embodiment of the present application can accurately obtain the expressions of the positive and negative sequence reference voltages in the stationary coordinate system by performing the Park inverse transformation on the reference voltages in the positive and negative rotating coordinate systems, and add them to obtain the total reference voltage. The control strategy of the flexible DC converter is optimized, making the calculation of the modulation wave more accurate, thereby improving the dynamic response performance and system stability of the converter, and meeting the needs of the high-voltage and large-capacity flexible DC transmission system.

[0031] The third aspect of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the delay compensation method for improving the dynamic performance of a flexible DC converter as described in the above embodiment.

[0032] The fourth aspect of the present application provides a computer-readable storage medium, which stores a computer program. When the program is executed by a processor, it implements the delay compensation method for improving the dynamic performance of the flexible DC converter as described above.

[0033] A fifth aspect of the present application provides a computer program product, including a computer program. When the computer program is executed, it is used to implement the above-mentioned delay compensation method for improving the dynamic performance of the flexible DC converter.

[0034] The embodiment of the present application can collect the voltage and current signals of the grid connection point, combine the phase reference value generated by the grid control strategy, perform Parker transformation and positive and negative sequence decomposition, thereby realizing the conversion of the signal in the positive and negative sequence rotating coordinate system. This process not only improves the accuracy of signal processing, but also optimizes the dynamic response capability of the system. Then, according to the inner and outer loop control strategies, the reference voltage is accurately calculated, and the Parker inverse transformation is performed according to the phase angle after delay compensation to obtain the total reference voltage in the stationary coordinate system. This method of integrating real-time data and control strategy significantly improves the responsiveness and control accuracy of the converter to grid fluctuations, ensures the efficient and stable operation of the high-voltage and large-capacity flexible DC transmission system, and thus better supports the transmission needs of new energy.

[0035] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0037] Figure 1 A flowchart of a delay compensation method for improving the dynamic performance of a flexible DC converter provided according to an embodiment of the present application;

[0038] Figure 2 A schematic diagram of the structure of a delay compensation device for improving the dynamic performance of a flexible DC converter provided according to an embodiment of the present application;

[0039] Figure 3 The figure is a structural example diagram of an electronic device provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0040] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0041] The following describes the delay compensation method and device for improving the dynamic performance of the flexible DC converter according to the embodiment of the present application with reference to the accompanying drawings. In view of the problem that the delay compensation method of the grid-type flexible DC converter in the related art mentioned in the above background technology relies on a phase-locked loop and is not suitable for a grid-type flexible DC converter without a phase-locked loop, the present application provides a delay compensation method for improving the dynamic performance of the flexible DC converter. In this method, the voltage and current signals of the grid-connected point of the flexible DC converter can be collected and the corresponding Parker transformation phase angle can be determined to effectively convert the signals into voltage and current signals in the positive and negative sequence rotating coordinate system. Then, based on the inner and outer loop control of the grid-type flexible DC converter, the corresponding reference voltage is calculated, and the Parker inverse transformation is performed according to the phase angle value after the delay compensation, so as to obtain the reference voltage in the stationary coordinate system and complete the modulation. This process optimizes the phase angle characteristics of the system, significantly improves the dynamic response performance and stability of the high-voltage and large-capacity flexible DC transmission system, and helps to better support the efficient transmission of new energy. Thereby, the problem in the related art that the delay compensation method of the grid-following flexible DC converter relies on a phase-locked loop and is not suitable for a grid-forming flexible DC converter without a phase-locked loop is solved.

[0042] Specifically, Figure 1 A schematic flow chart of a delay compensation method for improving the dynamic performance of a flexible DC converter provided in an embodiment of the present application.

[0043] like Figure 1 As shown, the delay compensation method for improving the dynamic performance of the flexible DC converter includes the following steps:

[0044] In step S101, the grid connection point voltage signal and current signal of the flexible DC converter in a stationary coordinate system are collected, and the phase angle used for Park transformation is determined to obtain the voltage signal and current signal in the positive and negative sequence rotating coordinate systems respectively.

[0045] In the actual implementation process, the grid connection point voltage signal of the flexible DC converter in the stationary coordinate system is collected as u abc , the current signal is i abc .

[0046] Furthermore, the phase angle used for Park transformation is determined to obtain voltage signals and current signals in positive and negative sequence rotating coordinate systems, respectively, including: determining to generate a phase reference value according to the grid control strategy of the flexible DC converter, and using the phase reference value as the phase angle used for Park transformation; using the phase angle to perform Park transformation and positive and negative sequence decomposition on the grid connection point voltage signal and current signal in the stationary coordinate system, so as to obtain voltage signals and current signals in the positive sequence rotating coordinate system and voltage signals and current signals in the negative sequence rotating coordinate system, respectively.

[0047] Specifically, the phase angle used for Parker transformation is determined according to the grid control strategy of the flexible DC converter. The grid-type flexible DC converter does not rely on the phase-locked loop to track the grid phase, but generates the voltage amplitude reference value E and the phase reference value θ1 through the grid control link, including but not limited to droop control, virtual synchronous machine control, etc., and uses the phase reference value θ1 as the angle used for Parker transformation. For the grid connection point voltage signal u in the stationary coordinate system abc and the current signal i abc Perform Park transformation and positive and negative sequence decomposition to obtain the voltage signal u in the positive sequence rotating coordinate system dqP and the current signal i dqP , and the voltage signal u in the negative sequence rotating coordinate system dqN and the current signal i dqN .

[0048] Taking the voltage signal as an example, the Park transformation and positive and negative sequence decomposition process can be expressed as follows:

[0049]

[0050]

[0051] Among them, G pns Represents the calculation matrix of the positive and negative sequence decomposition algorithm. The Parker transform of the current signal is similar to the positive and negative sequence decomposition process.

[0052] The embodiment of the present application can collect the grid connection point voltage signal and current signal of the flexible DC converter in the stationary coordinate system, and determine the phase angle required for Parker transformation in combination with the grid control strategy, effectively perform Parker transformation and positive and negative sequence decomposition, thereby obtaining the voltage and current signals in the positive and negative sequence rotating coordinate systems respectively. This process optimizes the phase angle characteristics of the system, improves the dynamic response performance of the high-voltage and large-capacity flexible DC transmission system, and enhances the stability of the system.

[0053] In step S102, based on the voltage signal and the current signal, a reference voltage in a positive and negative sequence rotating coordinate system is calculated according to the inner and outer loop controls of the grid-type flexible DC converter.

[0054] In the actual implementation process, based on the voltage signal and the current signal, the reference voltage in the positive and negative sequence rotating coordinate system is calculated according to the inner and outer loop controls of the meshed flexible DC converter, including: inputting the voltage signal and the current signal and the voltage amplitude reference value generated by the meshed control link into the inner and outer loop controllers of the flexible DC converter to obtain the reference voltage in the positive and negative sequence rotating coordinate system.

[0055] Specifically, the voltage signal u in the rotating coordinate system is dq and the current signal i dqThe voltage amplitude reference value E generated by the grid control link is input into the inner and outer loop controllers of the flexible DC converter. The outer loop can generally use AC voltage control to generate a positive sequence current reference value Input to the positive sequence current inner loop; negative sequence current reference value Set to zero.

[0056] Furthermore, the positive and negative sequence current inner loops generate reference voltages in the positive and negative sequence rotating coordinate systems respectively. It can be expressed as:

[0057]

[0058]

[0059] Among them, G i is the transfer function of the PI link of the current inner loop of the flexible DC converter; is the positive sequence current reference value; i dqP is the current signal in the positive sequence rotating coordinate system; k d is the decoupling coefficient of the inner current loop; u dqP is the voltage signal in the positive sequence rotating coordinate system; i dqN is the current signal in the negative sequence rotating coordinate system; u dqN It is the voltage signal in the negative sequence rotating coordinate system.

[0060] The embodiment of the present application can effectively calculate the reference voltage in the positive and negative sequence rotating coordinate system by inputting the voltage signal and current signal and the voltage amplitude reference value generated by the network control link into the inner and outer loop controllers of the flexible DC converter. This method uses AC voltage control to ensure the reasonable setting of the generated positive sequence current reference value and negative sequence current reference value, thereby optimizing the dynamic performance of the converter. Specifically, the reference voltages generated by the positive and negative sequence current inner loops not only improve the response speed of the system, but also enhance the stability and reliability of the system in high-voltage and large-capacity flexible DC transmission.

[0061] In step S103, the phase angle value after delay compensation is determined according to the flexible DC converter delay, and the reference voltage in the positive and negative sequence rotating coordinate system is subjected to an inverse Park transformation based on the phase angle value to obtain the reference voltage in the stationary coordinate system and perform modulation.

[0062] When determining the phase angle value after delay compensation, the calculation formula is:

[0063] θ inv =θ1+Δθ

[0064] Δθ=θ1+ω1T d

[0065] Among them, θ invis the phase angle value after compensation; Δθ is the additional phase angle; ω1 is the power frequency angular frequency; T d Delay for the flexible DC converter.

[0066] Optionally, in one embodiment of the present application, a Park inverse transform is performed on the reference voltage in the positive and negative sequence rotating coordinate system based on the phase angle value to obtain a reference voltage in the stationary coordinate system and modulate it, including: performing an inverse Park in the reference voltage in the positive and negative sequence rotating coordinate system based on the phase angle value to obtain an expression of the positive sequence reference voltage in the stationary coordinate system and an expression of the negative sequence reference voltage in the stationary coordinate system, respectively; adding the positive sequence reference voltage and the negative sequence reference voltage to obtain a total reference voltage; calculating the modulation waves of the upper and lower bridge arms of the flexible DC converter based on the total reference voltage to determine the on and off control signals of the switching device.

[0067] Among them, the reference voltage in the positive sequence rotating coordinate system is subjected to the Park inverse transformation, and the expression of the positive sequence reference point voltage in the stationary coordinate system is obtained as follows:

[0068]

[0069] Performing the Park inverse transformation on the reference voltage in the negative sequence rotating coordinate system, the expression of the negative sequence reference voltage in the stationary coordinate system is obtained as follows:

[0070]

[0071] Furthermore, the positive sequence reference voltage in the stationary coordinate system is and negative sequence reference voltage Add together to get the total reference voltage Total voltage The expression is:

[0072]

[0073] Finally, the total reference voltage The modulation waves of the upper and lower bridge arms of the flexible DC converter are calculated, and the on and off control signals of the switching devices are determined to complete the control and modulation process of the flexible DC converter. Specifically, the modulation wave can be used to generate the switch control signal after appropriate processing. These control signals determine the on and off timing of the switching device. The on signal of the switching device will be issued at the rising edge of the modulation wave or a specific threshold, while the off signal will be issued at the falling edge of the modulation wave or another specific threshold. Through precise control, the converter can achieve rapid regulation of current and voltage, thereby optimizing the dynamic response performance of the power system.

[0074] The embodiment of the present application can optimize the dynamic performance of the grid-type flexible DC converter through a delay compensation method. Specifically, by accurately calculating the phase angle value after delay compensation and performing a Park inverse transformation on the reference voltage in the positive and negative sequence rotating coordinate system, the reference voltage in the stationary coordinate system can be effectively obtained. This process ensures that the converter has better dynamic response capabilities in high-voltage and large-capacity power transmission systems, thereby improving the stability of the system. In addition, through the calculation of the total reference voltage, the opening and closing of the switching devices can be accurately controlled, thereby achieving rapid regulation of current and voltage, and further optimizing the overall performance of the power system.

[0075] According to the delay compensation method for improving the dynamic performance of the flexible DC converter proposed in the embodiment of the present application, the voltage and current signals at the grid connection point of the flexible DC converter can be collected and the corresponding Parker transformation phase angle can be determined to effectively convert the signals into voltage and current signals in the positive and negative sequence rotating coordinate system. Then, based on the inner and outer loop control of the meshed flexible DC converter, the corresponding reference voltage is calculated, and the Parker inverse transformation is performed according to the phase angle value after delay compensation, so as to obtain the reference voltage in the stationary coordinate system and complete the modulation. This process optimizes the phase angle characteristics of the system, significantly improves the dynamic response performance and stability of the high-voltage and large-capacity flexible DC transmission system, and helps to better support the efficient transmission of new energy.

[0076] Next, a delay compensation device for improving the dynamic performance of a flexible DC converter proposed in an embodiment of the present application will be described with reference to the accompanying drawings.

[0077] Figure 2 It is a block diagram of a delay compensation device for improving the dynamic performance of a flexible DC converter according to an embodiment of the present application.

[0078] like Figure 2 As shown, the delay compensation device 10 for improving the dynamic performance of the flexible DC converter includes: a collection module 100 , a calculation module 200 and a compensation module 300 .

[0079] Specifically, the acquisition module 100 is used to acquire the grid connection point voltage signal and current signal of the flexible DC converter in a stationary coordinate system, and determine the phase angle used for Park transformation to obtain the voltage signal and current signal in the positive and negative sequence rotating coordinate systems respectively.

[0080] The calculation module 200 is used to calculate the reference voltage in the positive and negative sequence rotating coordinate system based on the voltage signal and the current signal according to the inner and outer loop control of the grid-type flexible DC converter.

[0081] The compensation module 300 is used to determine the phase angle value after delay compensation according to the flexible DC converter delay, and perform a Park inverse transformation on the reference voltage in the positive and negative sequence rotating coordinate system based on the phase angle value to obtain the reference voltage in the stationary coordinate system and perform modulation.

[0082] Optionally, in one embodiment of the present application, the acquisition module 100 includes: a transformation unit and a decomposition unit.

[0083] Among them, the conversion unit is used to determine and generate a phase reference value according to the grid control strategy of the flexible DC converter, and use the phase reference value as the phase angle used for Parker transformation.

[0084] The decomposition unit is used to perform Park transformation and positive and negative sequence decomposition on the grid connection point voltage signal and current signal in the stationary coordinate system by using the phase angle, so as to obtain the voltage signal and current signal in the positive sequence rotating coordinate system and the voltage signal and current signal in the negative sequence rotating coordinate system respectively.

[0085] Optionally, in one embodiment of the present application, the calculation module 200 includes: inputting the voltage signal, the current signal and the voltage amplitude reference value generated by the network control link into the inner and outer loop controllers of the flexible DC converter to obtain a reference voltage in the positive and negative sequence rotating coordinate system.

[0086] Optionally, in one embodiment of the present application, the calculation module 200 includes: the reference voltages in the positive and negative sequence rotating coordinate systems are respectively:

[0087]

[0088]

[0089] Among them, G i is the transfer function of the PI link of the current inner loop of the flexible DC converter; is the positive sequence current reference value; i dqP is the current signal in the positive sequence rotating coordinate system; k d is the decoupling coefficient of the inner current loop; u dqP is the voltage signal in the positive sequence rotating coordinate system; i dqN is the current signal in the negative sequence rotating coordinate system; u dqN It is the voltage signal in the negative sequence rotating coordinate system.

[0090] Optionally, in one embodiment of the present application, the compensation module 300 includes: an inverse transformation unit, a summing unit and a modulation unit.

[0091] Among them, the inverse transformation unit is used to perform Park inverse transformation on the reference voltage in the positive and negative rotating coordinate systems based on the phase angle value, so as to obtain the expression of the positive sequence reference voltage in the stationary coordinate system and the expression of the negative sequence reference voltage in the stationary coordinate system respectively.

[0092] The summing unit is used for adding the positive sequence reference voltage and the negative sequence reference voltage to obtain a total reference voltage.

[0093] The modulation unit is used to calculate the modulation waves of the upper and lower bridge arms of the flexible DC converter according to the total reference voltage to determine the on and off control signals of the switching device.

[0094] It should be noted that the above explanation of the delay compensation method embodiment for improving the dynamic performance of a flexible DC converter is also applicable to the delay compensation device for improving the dynamic performance of a flexible DC converter in this embodiment, and will not be repeated here.

[0095] According to the delay compensation device for improving the dynamic performance of the flexible DC converter proposed in the embodiment of the present application, the signal can be effectively converted into a voltage and current signal in a positive and negative sequence rotating coordinate system by collecting the voltage and current signals at the grid connection point of the flexible DC converter and determining the corresponding Parker transformation phase angle. Then, based on the inner and outer loop control of the meshed flexible DC converter, the corresponding reference voltage is calculated, and the Parker inverse transformation is performed according to the phase angle value after delay compensation, so as to obtain the reference voltage in the stationary coordinate system and complete the modulation. This process optimizes the phase angle characteristics of the system, significantly improves the dynamic response performance and stability of the high-voltage and large-capacity flexible DC transmission system, and helps to better support the efficient transmission of new energy.

[0096] Figure 3 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. The electronic device may include:

[0097] A memory 301 , a processor 302 , and a computer program stored in the memory 301 and executable on the processor 302 .

[0098] When the processor 302 executes the program, the delay compensation method for improving the dynamic performance of the flexible DC converter provided in the above embodiment is implemented.

[0099] Furthermore, the electronic device further comprises:

[0100] The communication interface 303 is used for communication between the memory 301 and the processor 302 .

[0101] The memory 301 is used to store computer programs that can be run on the processor 302 .

[0102] The memory 301 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0103] If the memory 301, the processor 302 and the communication interface 303 are implemented independently, the communication interface 303, the memory 301 and the processor 302 can be connected to each other through a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 3 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0104] Optionally, in a specific implementation, if the memory 301, the processor 302 and the communication interface 303 are integrated on a chip, the memory 301, the processor 302 and the communication interface 303 can communicate with each other through an internal interface.

[0105] The processor 302 may be a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0106] An embodiment of the present application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the delay compensation method for improving the dynamic performance of a flexible DC converter as described above.

[0107] An embodiment of the present application also provides a computer program product, including a computer program, which, when executed, is used to implement the above-mentioned delay compensation method for improving the dynamic performance of the flexible DC converter.

[0108] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0109] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0110] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0111] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or N wirings (electronic devices), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways as necessary and then storing it in a computer memory.

[0112] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above embodiment, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. If implemented by hardware, as in another embodiment, it can be implemented by any one or a combination of multiple of the following technologies known in the art: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0113] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0114] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0115] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A delay compensation method for improving the dynamic performance of a flexible DC converter, characterized in that: The following steps are involved: Collect the voltage signal and current signal of the grid connection point of the flexible DC converter in the stationary coordinate system, and determine the phase angle used for Parker transformation to obtain the voltage signal and current signal in the positive and negative sequence rotating coordinate system respectively; Based on the voltage signal and the current signal, the reference voltage in the positive and negative sequence rotating coordinate system is calculated according to the inner and outer loop controls of the grid-type flexible DC converter; The phase angle value after delay compensation is determined according to the flexible DC converter delay, and based on the phase angle value, the reference voltage in the positive and negative sequence rotating coordinate system is subjected to an inverse Park transformation to obtain the reference voltage in the stationary coordinate system and perform modulation.

2. The method according to claim 1, characterized in that The phase angle used for Park transformation is determined to obtain voltage signals and current signals in positive and negative sequence rotating coordinate systems, respectively, including: Determine and generate a phase reference value according to the grid control strategy of the flexible DC converter, and use the phase reference value as the phase angle used for the Parker transformation; The phase angle is used to perform Park transformation and positive-negative sequence decomposition on the grid connection point voltage signal and current signal in the stationary coordinate system to obtain the voltage signal and current signal in the positive-sequence rotating coordinate system and the voltage signal and current signal in the negative-sequence rotating coordinate system respectively.

3. The method according to claim 1, characterized in that The calculating of the reference voltage in the positive and negative sequence rotating coordinate system based on the voltage signal and the current signal according to the inner and outer loop control of the grid-type flexible DC converter includes: The voltage signal, the current signal and the voltage amplitude reference value generated by the network control link are input into the inner and outer loop controllers of the flexible DC converter to obtain the reference voltage in the positive and negative sequence rotating coordinate system.

4. The method according to claim 3, characterized in that The reference voltages in the positive and negative sequence rotating coordinate systems are: Among them, G i is the transfer function of the PI link of the current inner loop of the flexible DC converter; is the positive sequence current reference value; i dqP is the current signal in the positive sequence rotating coordinate system; k d is the decoupling coefficient of the inner current loop; u dqP is the voltage signal in the positive sequence rotating coordinate system; i dqN is the current signal in the negative sequence rotating coordinate system; u dqN It is the voltage signal in the negative sequence rotating coordinate system.

5. The method according to claim 1, characterized in that The inverse Park transformation of the reference voltage in the positive and negative sequence rotating coordinate system based on the phase angle value to obtain the reference voltage in the stationary coordinate system and perform modulation includes: Performing an inverse Park transformation on the reference voltage in the positive and negative rotating coordinate systems based on the phase angle value to obtain an expression of the positive sequence reference voltage in the stationary coordinate system and an expression of the negative sequence reference voltage in the stationary coordinate system respectively; adding the positive-sequence reference voltage and the negative-sequence reference voltage to obtain a total reference voltage; The modulation waves of the upper and lower bridge arms of the flexible DC converter are calculated according to the total reference voltage to determine the on and off control signals of the switching device.

6. A delay compensation device for improving the dynamic performance of a flexible DC converter, characterized in that: The following steps are involved: The acquisition module is used to acquire the voltage signal and current signal of the grid connection point of the flexible DC converter in the stationary coordinate system, and determine the phase angle used for Parker transformation to obtain the voltage signal and current signal in the positive and negative sequence rotating coordinate system respectively; A calculation module, configured to calculate the reference voltage in the positive and negative sequence rotating coordinate system based on the voltage signal and the current signal and according to the inner and outer loop controls of the grid-type flexible DC converter; The compensation module is used to determine the phase angle value after delay compensation according to the flexible DC converter delay, and perform a Park inverse transformation on the reference voltage in the positive and negative sequence rotating coordinate system based on the phase angle value to obtain the reference voltage in the stationary coordinate system and perform modulation.

7. The device according to claim 6, characterized in that The acquisition module comprises: A transformation unit, configured to determine and generate a phase reference value according to a grid control strategy of the flexible DC converter, and use the phase reference value as a phase angle used for the Parker transformation; The decomposition unit is used to perform Park transformation and positive-negative sequence decomposition on the grid connection point voltage signal and current signal in the stationary coordinate system using the phase angle, so as to obtain the voltage signal and current signal in the positive-sequence rotating coordinate system and the voltage signal and current signal in the negative-sequence rotating coordinate system respectively.

8. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the delay compensation method for improving the dynamic performance of a flexible DC converter as described in any one of claims 1 to 5.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the delay compensation method for improving the dynamic performance of a flexible DC converter as described in any one of claims 1 to 5.

10. A computer program product, comprising a computer program, characterized in that The computer program is executed to implement the delay compensation method for improving the dynamic performance of a flexible DC converter as described in any one of claims 1 to 5.

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