MMC valve pilot-scale test platform test loop and reconnection method, equipment and medium of MMC valve pilot-scale test platform test loop

Abstract

The invention relates to an MMC valve pilot test platform test loop and a reconnection method, equipment and medium thereof, and the method comprises the steps: enabling the test loop to be provided with a first-model upper bridge arm equivalent sub-loop and a second-model upper bridge arm equivalent sub-loop on an upper bridge arm, and enabling the first-model upper bridge arm equivalent sub-loop and the second-model upper bridge arm equivalent sub-loop to be connected through a circuit breaker; setting a loop reconnection enabling signal, comparing the loop reconnection enabling signal with a threshold value to generate a complementary control quantity, and controlling closing or opening in the two groups of circuit breakers to realize reconnection; and selecting a valve-controlled input voltage measurement signal according to the signal, so that the valve-controlled input voltage measurement is consistent with the currently accessed upper bridge arm equivalent sub-loop. After the test of one model is completed and the result is recorded, simulation is stopped, the initial state of the test loop is reinitialized, and then the signal is changed to carry out the test of another model. Compared with the prior art, quick and repeatable reconnection configuration of the equivalent test loop of the pilot test platform is realized, the risk of manual reconnection and configuration errors is reduced, and the test efficiency of equivalent tests of different bridge arm models is improved.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic transient simulation technology for power systems, and in particular to a test circuit for an MMC valve pilot platform and its reconnection method, equipment and medium. Background Technology

[0002] As a core component of flexible DC transmission, the modular multilevel converter (MMC) converter valve (hereinafter referred to as MMC valve) typically contains a large number of insulated gate bipolar transistors (IGBTs). Since IGBTs are highly sensitive to critical electrical stresses such as temperature, voltage, current, and their rates of change, it is usually necessary to conduct corresponding operational verification tests before design finalization and factory delivery to verify the reliability and operating characteristics of large-capacity MMC valves under expected operating conditions. Considering the high cost and large power supply capacity requirements of directly conducting full-power tests on the entire valve, adopting an equivalent operational test topology to reproduce the valve voltage, current, and switching stress in actual engineering under limited power supply capacity conditions is of great significance. Therefore, it is often necessary to build an equivalent test loop for the MMC valve pilot test platform in an electromagnetic transient simulation platform (such as PSCAD / EMTDC) to obtain key indicators such as bridge arm voltage and current stress through simulation tests, which can be used to compare and verify different bridge arm model schemes, parameter configuration schemes, or equivalent modeling schemes.

[0003] In existing technologies, to balance simulation accuracy and computational efficiency, MMC bridge arm models typically employ various modeling methods. These include detailed models that discretely model devices and components such as IGBTs, anti-parallel diodes, and submodule capacitors, as well as submodule equivalent models based on the Thevenin equivalence principle. Different modeling methods differ in simulation speed, fitted voltage and current waveforms, device stress characterization, and switching transient details. In engineering practice, multiple rounds of simulation experiments are often required on different bridge arm equivalent models under the same experimental boundary conditions to evaluate model applicability and verify control and protection strategies.

[0004] However, in existing MMC valve simulation tests, the switching between equivalent models of different bridge arms and the reconnection of test loops mostly rely on manual operations. These include manually modifying circuit breaker states, manually changing measurement signal connections, manually adjusting valve control input channels, or repeatedly building simulation project files. These methods are not only cumbersome and time-consuming, but also prone to test failures or incomparable results due to configuration omissions, connection errors, or parameter asynchronization, thus affecting the accuracy and efficiency of comparative evaluation. Especially when it is necessary to repeatedly test multiple bridge arm models and compare their transient responses under the same initial conditions, there is a lack of a test loop reconnection technology that can achieve bridge arm model reconnection, synchronous selection of measurement signals, and support the reinitialization of the test loop's initial state before and after the test within the same simulation test loop.

[0005] Therefore, there is an urgent need for a test circuit and its reconnection method for equivalent testing on MMC valve pilot platforms, so as to achieve rapid, accurate and repeatable reconnection configuration of equivalent sub-circuits of different bridge arms, reduce the risk of manual rewiring and configuration errors, and improve the efficiency and comparability of equivalent tests of different bridge arm models. Summary of the Invention

[0006] The purpose of this invention is to overcome the defects of the prior art by providing a pilot-scale test circuit for MMC valves, as well as its reconnection method, equipment, and medium. This invention enables rapid and repeatable reconnection and configuration of the equivalent test circuit of the pilot-scale platform, reduces the risk of manual rewiring and configuration errors, and improves the test efficiency of equivalent tests for different bridge arm models.

[0007] The objective of this invention can be achieved through the following technical solutions: A pilot-scale test platform for an MMC valve, wherein the test circuit is an equivalent test circuit model of the MMC valve built based on simulation software, including valve-side connection nodes, equivalent branches of the upper bridge arm, equivalent branches of the lower bridge arm, and valve control input signal channels, wherein: The upper arm equivalent branch includes a first-type upper arm equivalent sub-circuit, a second-type upper arm equivalent sub-circuit, and circuit breakers corresponding to each. The test circuit also includes an ArmSwitch signal, a comparison module, and a signal selection module. The comparison module compares the ArmSwitch signal with a threshold and outputs a complementary control quantity to control the circuit breaker to selectively connect one of the two types of upper arm equivalent sub-circuits. The signal selection module selects between the voltage measurement signal of the first-type upper arm equivalent sub-circuit and the voltage measurement signal of the second-type upper arm equivalent sub-circuit based on the ArmSwitch signal, and uses the selected voltage measurement signal as a valve control input signal.

[0008] Furthermore, the equivalent sub-loop of the upper arm in both the first and second models is a hybrid modeled upper arm composed of detailed sub-modules and equivalent sub-module groups connected in series; wherein, The detailed sub-modules include discrete modeling of IGBTs, anti-parallel diodes, and capacitors; The equivalent submodule group consists of submodules obtained through Thevenin equivalence.

[0009] Furthermore, the Thevenin equivalent submodule uses an equivalent voltage source and equivalent impedance to characterize the external port characteristics of the submodule, and retains the equivalent capacitance parameters used to fit the energy storage effect of the submodule.

[0010] A method for modifying the test circuit based on the MMC valve pilot-scale test platform as described above, the method comprising: Step S1: Set the loop reconnection enable signal ArmSwitch, where ArmSwitch is 0 or 1, used to indicate the selection of the first or second model upper arm equivalent sub-loop; Step S2: Compare ArmSwitch with the threshold to generate a first control quantity C1 and a second control quantity C2, the first control quantity and the second control quantity being complementary; Step S3: Configure the circuit breaker according to the first control quantity and the second control quantity, and perform the first model test or the second model test; Step S4: Select the voltage measurement signal from the equivalent sub-circuit of the first upper arm and the equivalent sub-circuit of the second upper arm based on the ArmSwitch signal, and use it as the voltage measurement signal for valve control input. Step S5: After completing the circuit breaker configuration and valve control input signal selection, perform the test and record the test results. After completing the first model test or the second model test, change the ArmSwitch and repeat S2 to S5 to complete another test.

[0011] Further, the threshold is 0.5; when the ArmSwitch is greater than or equal to 0.5, the first control quantity C1=1 and the second control quantity C2=0, and when the ArmSwitch is less than 0.5, the first control quantity C1=0 and the second control quantity C2=1.

[0012] Furthermore, the circuit breaker includes at least a first circuit breaker group and a second circuit breaker group. The first circuit breaker group is used to connect the equivalent sub-circuit of the upper bridge arm of the first type to the test circuit, and the second circuit breaker group is used to connect the equivalent sub-circuit of the upper bridge arm of the second type to the test circuit. The first control quantity and the second control quantity are complementary. When the first control quantity C1=1, the first circuit breaker combination is driven and the second circuit breaker group is driven. When the second control quantity C2=1, the second circuit breaker combination is driven and the first circuit breaker group is driven, so as to achieve interlocking.

[0013] Furthermore, during a single test in step S5, the ArmSwitch is locked so that it remains unchanged during the test run. Only after the test ends and the simulation stops is the ArmSwitch unlocked to allow changes to the ArmSwitch, thereby preventing erroneous rewiring of the upper arm equivalent sub-circuit during the test run.

[0014] Furthermore, during a single test in step S5, after completing the test of the first model upper arm equivalent sub-circuit and recording the test results, the simulation is stopped and the test circuit is reinitialized. The reinitialization includes at least restoring the initial voltage of the upper arm capacitor, the initial voltage of the valve-side connection node, and the initial current of the valve-side connection node to preset initial values. Then, the ArmSwitch value is changed and steps S2 to S5 of claim 1 are executed to carry out the test of the second model upper arm equivalent sub-circuit.

[0015] An electronic device includes a processor and a memory, wherein the memory stores a computer program that, when executed by the processor, implements the test circuit reconnection method as described above.

[0016] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the test circuit reconnection method as described above.

[0017] Compared with the prior art, the beneficial effects of the present invention include: 1. This invention uses complementary control quantities to drive two sets of circuit breakers to achieve selective connection, and locks the circuit reconnection enable signal during a single test to avoid erroneous switching during test operation, reduce the risk of abnormal simulation results or test failure caused by circuit breaker misconfiguration or signal erroneous switching, and improve the reliability of the test process.

[0018] 2. This invention achieves the reconnection of one set of circuit breakers and the other set of circuit breakers by setting a circuit reconnection enable signal ArmSwitch and comparing it with a threshold to generate complementary control quantities. This eliminates the need for manual modification of circuit breaker status or repeated construction of simulation engineering files, thereby significantly reducing manual rewiring, manual configuration and the resulting workload.

[0019] 3. Based on the loop reconnection enable signal, this invention automatically selects between the voltage measurement signals corresponding to the equivalent sub-circuit of the bridge arm in two different models, so that the valve-controlled input voltage measurement is consistent with the currently connected bridge arm model, avoiding valve-controlled input errors caused by asynchronous switching of measurement channels, and improving the accuracy and repeatability of comparative tests.

[0020] 4. After completing one type of test, the present invention stops the simulation and reinitializes the initial voltage of the upper bridge arm capacitor, the initial voltage and initial current of the valve side connection node, so that the two types of tests are carried out under the same initial conditions, reducing the interference of the difference in initial state on the test results and improving the comparability of comparative verification.

[0021] 5. This invention supports simulation comparison between detailed models and equivalent submodule models based on Thevenin equivalence in the same test loop, which helps to improve simulation efficiency while ensuring the characterization of key transient characteristics and meets the verification requirements of pilot-scale platforms for various bridge arm model schemes. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the equivalent test circuit structure of the MMC valve pilot platform in an embodiment of the present invention; Figure 2 This is a schematic diagram of the circuit breaker reconnection control logic in an embodiment of the present invention; Figure 3 This is a schematic diagram of the main steps of the method of the present invention; Figure 4 This is a schematic diagram of the valve-controlled input voltage measurement signal selection logic in an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the hybrid modeling submodule in an embodiment of the present invention; Figure 6 This is a schematic diagram of the simulation system in an embodiment of the present invention; Figure 7 This refers to the capacitor voltage of the first type of upper bridge arm submodule before the test circuit is reconnected in this embodiment of the invention. Figure 8 This refers to the capacitor voltage of the second type upper bridge arm submodule after the test circuit was reconnected in this embodiment of the invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0024] Example 1 This embodiment discloses a pilot-scale test circuit for an MMC valve, the specific circuit structure of which is as follows: Figure 1 As shown, the test circuit is an equivalent test circuit model of the MMC valve built based on PSCAD electromagnetic transient simulation software, including valve-side connection nodes, equivalent branches of the upper bridge arm, equivalent branches of the lower bridge arm, and valve control input signal channels.

[0025] The upper arm equivalent branch includes a first-type upper arm equivalent sub-circuit, a second-type upper arm equivalent sub-circuit, and circuit breakers corresponding to each. The test circuit also includes an ArmSwitch signal, a comparison module, and a signal selection module. The comparison module compares the ArmSwitch signal with a threshold and outputs a complementary control quantity to control the circuit breaker to selectively connect one of the two types of upper arm equivalent sub-circuits. The signal selection module selects between the voltage measurement signal of the first-type upper arm equivalent sub-circuit and the voltage measurement signal of the second-type upper arm equivalent sub-circuit based on the ArmSwitch signal, and uses the selected voltage measurement signal as a valve control input signal.

[0026] The equivalent sub-loops of the upper arm in both the first and second models are hybrid modeled upper arms composed of detailed sub-modules and equivalent sub-module groups connected in series, such as... Figure 5 As shown. The detailed submodules include discrete modeling of IGBTs, anti-parallel diodes, and capacitors. The equivalent submodule group consists of submodules obtained through Thevenin equivalence. Hybrid modeling balances simulation efficiency and computational accuracy.

[0027] Figure 5 In the diagram, T1 is the upper IGBT switching device in the upper bridge arm detailed submodule, T2 is the lower IGBT switching device in the upper bridge arm detailed submodule, D1 is the anti-parallel diode corresponding to T1, and D2 is the anti-parallel diode corresponding to T2. Let C be the voltage across the submodule capacitor in the detailed submodule, and C be the submodule capacitor in the detailed submodule. This is the equivalent resistance of the Thevenin equivalent submodule. It serves as the equivalent voltage source for the Thevenin equivalent submodule, used to characterize the open-circuit equivalent voltage characteristics of the submodule group's external ports.

[0028] The Thevenin equivalent submodule uses an equivalent voltage source and equivalent impedance to characterize the external port characteristics of the submodule, and retains the equivalent capacitance parameters used to fit the energy storage effect of the submodule.

[0029] After completing the test of the first model upper arm equivalent sub-circuit and recording the test results, the simulation was stopped and the test circuit was reinitialized. The reinitialization included restoring the initial voltage of the upper arm capacitor, the initial voltage of the valve-side connection node, and the initial current of the valve-side connection node to the preset initial values, thereby eliminating the influence of the residual voltage, current, and energy storage state of the previous test on the next test, so that the two models of tests were carried out under the same initial conditions. Then, the ArmSwitch value was changed and the above steps S2 to S5 were executed to carry out the test of the second model upper arm equivalent sub-circuit.

[0030] By setting a loop reconnection enable signal and comparing it with a threshold to generate complementary control quantities, two sets of circuit breakers are interlocked to control the opening and closing of the circuit breakers, enabling selective access to the equivalent sub-circuit of the upper arm of the first and second models. Based on the loop reconnection enable signal, the voltage measurement signals of the two equivalent sub-circuit of the upper arm are selected to obtain a valve-controlled input voltage measurement signal that matches the currently accessed model. After completing the test of one model, the simulation is stopped and the initial state of the test circuit is reinitialized before the test of the other model is carried out. This allows for rapid and repeatable reconnection and comparative verification of different equivalent models of the bridge arm without changing the main topology of the equivalent test circuit on the pilot platform, reducing the risk of manual configuration errors and improving test efficiency and result comparability.

[0031] Example 2 This embodiment, based on the MMC valve pilot platform test circuit disclosed in Embodiment 1 above, discloses a method for modifying the test circuit, the specific process of which is as follows: Figure 3 As shown, it includes: Step S1: Set the loop reconnection enable signal ArmSwitch. ArmSwitch is 0 or 1, which is used to indicate whether to select the first or second model upper arm equivalent sub-loop.

[0032] Test apparatus such as Figure 1 As shown, a two-phase four-arm H-bridge type MMC valve operation test topology is adopted. The midpoints of the two phase arms are connected via load reactors, and DC power supplies and smoothing reactors are connected in parallel at both ends of the upper and lower arms to equivalently reproduce the AC / DC operating stress of the engineering MMC valve with a smaller power supply capacity. The equivalent sub-circuit of the first / second model upper arm and the circuit breaker reconnection structure are only set in the upper arm of phase A. It should be understood that the reconnection structure of this invention is also applicable to other phase configurations or other equivalent operation test topologies. For the upper arm of phase A where the test circuit reconnection is to be performed, the first model upper arm and the second model upper arm are connected in series via the first circuit breaker group and the second circuit breaker group, respectively.

[0033] Figure 1 middle, This is the DC power supply voltage. For bridge arm inductance, For load inductance, The AC voltage is output at the midpoint of the bridge arm of phase A unit. The output AC voltage is the midpoint of the bridge arm of phase B unit. , For the circuit breakers in the first circuit breaker group, , For the circuit breakers in the second circuit breaker group, This is the voltage measurement signal for the equivalent sub-circuit of the upper bridge arm of the first model. This is the voltage measurement signal for the equivalent sub-circuit of the upper bridge arm of the second model. This is the valve-side connection node.

[0034] Step S2: Compare ArmSwitch with the threshold to generate a first control quantity C1 and a second control quantity C2, which are complementary.

[0035] The threshold is 0.5. When ArmSwitch is greater than or equal to 0.5, that is, when ArmSwitch=1, the first control variable C1=1 and the second control variable C2=0. When ArmSwitch is less than 0.5, that is, when ArmSwitch=0, the first control variable C1=0 and the second control variable C2=1.

[0036] Step S3: Configure the circuit breaker according to the first control quantity and the second control quantity, and conduct the first model test or the second model test.

[0037] The circuit breaker reconnection control logic diagram is as follows: Figure 2 As shown. The circuit breaker in step S3 includes at least a first circuit breaker group and a second circuit breaker group. The first circuit breaker group is used to connect the equivalent sub-circuit of the upper bridge arm of the first type to the test circuit, and the second circuit breaker group is used to connect the equivalent sub-circuit of the upper bridge arm of the second type to the test circuit. The first control quantity and the second control quantity are complementary. When the first control quantity C1=1, all circuit breakers in the first circuit breaker group are driven to close, and all circuit breakers in the second circuit breaker group are driven to open. When the second control quantity C2=1, all circuit breakers in the second circuit breaker group are driven to close, and all circuit breakers in the first circuit breaker group are driven to open, so as to achieve interlocking.

[0038] Step S4: Select the voltage measurement signal from the equivalent sub-circuit of the first upper arm and the equivalent sub-circuit of the second upper arm based on the ArmSwitch signal, and use it as the voltage measurement signal for valve control input. like Figure 4 As shown, voltage measurement signals are obtained from the equivalent sub-circuit of the upper arm of the first model and the equivalent sub-circuit of the upper arm of the second model, respectively. and The voltage measurement signal is composed of capacitor voltage signals from the same model of fully detailed submodule and Thevenin equivalent submodule group. A signal selection module controlled by ArmSwitch is provided; in this embodiment, a two-channel selector is selected. When ArmSwitch ≥ 0.5, the two-channel selector outputs... When ArmSwitch < 0.5, the two-channel selector output... The aforementioned The input voltage measurement signal of the valve control module, along with the bridge arm current, participates in the valve control calculation. Specifically, the valve control module determines whether the bridge arm submodule is in a charging or discharging state based on the direction of the bridge arm current, and determines the number of submodules to be activated at each time point by combining the modulation wave. Based on this, the module sorts and selects submodules according to their capacitor voltage measurement values. When the module is determined to be in a charging state, the module with the lower capacitor voltage is activated first; when the module is determined to be in a discharging state, the module with the higher capacitor voltage is activated first. This achieves balanced control of the capacitor voltage of the submodules, ensuring that the valve control input voltage measurement is consistent with the equivalent sub-loop of the currently connected upper bridge arm, and avoiding valve control input errors caused by asynchronous switching of measurement channels.

[0039] Step S5: After completing the circuit breaker configuration and valve control input signal selection, perform the test and record the test results. After completing the first model test or the second model test, change the ArmSwitch and repeat S2 to S5 to complete another test.

[0040] During a single test in step S5, the ArmSwitch is locked so that it remains unchanged during the test run. Only after the test ends and the simulation stops is the ArmSwitch unlocked to allow changes to the ArmSwitch, thereby preventing erroneous rewiring of the upper arm equivalent sub-loop during the test run.

[0041] Example 3 This embodiment is based on Embodiments 1 and 2 above. In order to verify the effectiveness of the test circuit of the MMC valve pilot platform and its reconnection method of the present invention, a typical 27-level MMC valve test device simulation system is used as an example for verification.

[0042] The test setup employs a two-phase, four-bridge structure, with an equivalent operating test topology consisting of an H-bridge type MMC valve connected at the midpoints of the two phase arms via load inductance. The test circuit was reconnected on the upper arm of phase A. A schematic diagram of the simulation system is shown below. Figure 6 As shown in Table 1, the main parameters of the system are as follows.

[0043] Table 1 Main System Parameters The rectifier station employs constant DC voltage and constant reactive power control, transmitting power to the test circuit station via transmission lines. The test circuit station utilizes a closed-loop control strategy for DC and fundamental frequency currents, along with a second harmonic circulating current suppression method. The reference value for the rectifier station's DC voltage is 60kV, and the reference value for reactive power is 0. The reference value for the test circuit station's DC current is 0.531kA, and the reference value for the fundamental frequency current is 0.844kA.

[0044] The program used was built in the electromagnetic transient simulation program PSCAD / EMTDC V5.0.0, and the simulation step size was set to 50 microseconds.

[0045] Both the first and second type upper bridge arms consist of one detailed submodule and one equivalent submodule group (derived from Thevenin's equivalent) containing 25 submodules. The first type submodule has a capacitance of 6500μF, and the second type submodule has a capacitance of 8000μF. After the simulation reaches steady state, the voltage waveform of the first type upper bridge arm submodule capacitor before the circuit reconnection, from the 4th second to the 4.2th second, is as follows: Figure 7 As shown. After the simulation, the value of ArmSwitch was changed, re-initialized, and the experiment was conducted again. After the simulation reached steady state, the capacitor voltage of the second model upper bridge arm submodule after the test circuit was reconnected from the 4th second to the 4.2th second was as follows. Figure 8 As shown in the figure, the pilot test circuit of the MMC valve and its modification method described in this invention have good results.

[0046] Example 4 The electronic device of this invention includes a central processing unit (CPU), which can perform various appropriate actions and processes according to computer program instructions stored in read-only memory (ROM) or loaded from a storage unit into random access memory (RAM). The RAM may also store various programs and data required for device operation. The CPU, ROM, and RAM are interconnected via a bus. Input / output (I / O) interfaces are also connected to the bus.

[0047] Multiple components in the device are connected to the I / O interface, including: input units such as keyboards and mice; output units such as various types of displays and speakers; storage units such as disks and optical discs; and communication units such as network interface cards (NICs), modems, and wireless transceivers. The communication unit allows the device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0048] The processing unit executes the various methods and processes described above, such as steps S1 to S5. For example, in some embodiments, steps S1 to S5 may be implemented as a computer software program tangibly contained in a machine-readable medium, such as a storage unit. In some embodiments, part or all of the computer program may be loaded and / or installed on the device via ROM and / or a communication unit. When the computer program is loaded into RAM and executed by the CPU, one or more steps S1 to S5 described above may be performed. Alternatively, in other embodiments, the CPU may be configured to execute steps S1 to S5 by any other suitable means (e.g., by means of firmware).

[0049] The functions described above in this document can be performed, at least in part, by one or more hardware logic components. For example, exemplary types of hardware logic components that can be used, without limitation, include: Field Programmable Gate Arrays (FPGAs), Application-Specific Integrated Circuits (ASICs), Application Standard Products (ASSPs), System-on-Chip (SoCs), Complex Programmable Logic Devices (CPLDs), and so on.

[0050] The program code used to implement the methods of the present invention can be written in any combination of one or more programming languages. This program code can be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code can be executed entirely on the machine, partially on the machine, as a standalone software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0051] In the context of this invention, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0052] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0053] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A pilot-scale test circuit for an MMC valve, characterized in that, The test circuit is an equivalent test circuit model of an MMC valve built based on simulation software, including valve-side connection nodes, equivalent branches of the upper bridge arm, equivalent branches of the lower bridge arm, and valve control input signal channels, wherein: The upper arm equivalent branch includes a first-type upper arm equivalent sub-circuit, a second-type upper arm equivalent sub-circuit, and circuit breakers corresponding to each. The test circuit also includes an ArmSwitch signal, a comparison module, and a signal selection module. The comparison module compares the ArmSwitch signal with a threshold and outputs a complementary control quantity to control the circuit breaker to selectively connect one of the two types of upper arm equivalent sub-circuits. The signal selection module selects between the voltage measurement signal of the first-type upper arm equivalent sub-circuit and the voltage measurement signal of the second-type upper arm equivalent sub-circuit based on the ArmSwitch signal, and uses the selected voltage measurement signal as a valve control input signal.

2. The test circuit for an MMC valve pilot plant according to claim 1, characterized in that, The first-type upper bridge arm equivalent sub-loop and the second-type upper bridge arm equivalent sub-loop are hybrid modeling upper bridge arms composed of detailed sub-modules and equivalent sub-module groups connected in series; wherein... The detailed sub-modules include discrete modeling of IGBTs, anti-parallel diodes, and capacitors; The equivalent submodule group consists of submodules obtained through Thevenin equivalence.

3. The test circuit for an MMC valve pilot plant according to claim 2, characterized in that, The Thevenin equivalent submodule uses an equivalent voltage source and equivalent impedance to characterize the external port characteristics of the submodule, and retains the equivalent capacitance parameters used to fit the energy storage effect of the submodule.

4. A method for modifying a test circuit based on the test circuit of an MMC valve pilot platform as described in any one of claims 1-3, characterized in that, The method includes: Step S1: Set the loop reconnection enable signal ArmSwitch, where ArmSwitch is 0 or 1, used to indicate the selection of the first or second model upper arm equivalent sub-loop; Step S2: Compare ArmSwitch with the threshold to generate a first control quantity C1 and a second control quantity C2, wherein the first control quantity and the second control quantity are complementary; Step S3: Configure the circuit breaker according to the first control quantity and the second control quantity, and perform the first model test or the second model test; Step S4: Select the voltage measurement signal from the equivalent sub-circuit of the first upper arm and the equivalent sub-circuit of the second upper arm based on the ArmSwitch signal, and use it as the voltage measurement signal for valve control input. Step S5: After completing the circuit breaker configuration and valve control input signal selection, perform the test and record the test results. After completing the first model test or the second model test, change the ArmSwitch and repeat S2 to S5 to complete another test.

5. The test circuit reconnection method according to claim 4, characterized in that, The threshold is 0.5; when the ArmSwitch is greater than or equal to 0.5, the first control quantity C1 = 1 and the second control quantity C2 = 0; when the ArmSwitch is less than 0.5, the first control quantity C1 = 0 and the second control quantity C2 = 1.

6. The test circuit reconnection method according to claim 4, characterized in that, The circuit breaker includes at least a first circuit breaker group and a second circuit breaker group. The first circuit breaker group is used to connect the equivalent sub-circuit of the upper bridge arm of the first type to the test circuit, and the second circuit breaker group is used to connect the equivalent sub-circuit of the upper bridge arm of the second type to the test circuit. The first control quantity and the second control quantity are complementary. When the first control quantity C1=1, the first circuit breaker combination is driven and the second circuit breaker group is driven. When the second control quantity C2=1, the second circuit breaker combination is driven and the first circuit breaker group is driven, so as to achieve interlocking.

7. The test circuit reconnection method according to claim 4, characterized in that, During a single test in step S5, the ArmSwitch is locked so that it remains unchanged during the test run. Only after the test ends and the simulation stops is the ArmSwitch unlocked to allow changes to the ArmSwitch, thereby preventing erroneous rewiring of the upper arm equivalent sub-loop during the test run.

8. The test circuit reconnection method according to claim 4, characterized in that, During a single test in step S5, after completing the test of the first model upper arm equivalent sub-circuit and recording the test results, the simulation is stopped and the test circuit is reinitialized. The reinitialization includes at least restoring the initial voltage of the upper arm capacitor, the initial voltage of the valve-side connection node, and the initial current of the valve-side connection node to preset initial values. Then, the ArmSwitch value is changed and steps S2 to S5 of claim 1 are executed to carry out the test of the second model upper arm equivalent sub-circuit.

9. An electronic device, characterized in that, It includes a processor and a memory, wherein the memory stores a computer program, which, when executed by the processor, implements the test circuit reconnection method according to any one of claims 4 to 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the test circuit reconnection method according to any one of claims 4 to 8.

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