A device and control method for simulating the operating conditions of a flexible DC converter valve

Abstract

This invention discloses a simulation device for the operating conditions of a flexible DC converter valve, characterized by comprising: a three-phase current generator, a first control module, an in-phase parallel current generator, a module under test, and a second control module; the three-phase current generator is electrically connected to the first control module, the in-phase parallel current generator, and the module under test; the in-phase parallel current generator is electrically connected to the module under test; and the second control module is electrically connected to the in-phase parallel current generator and the module under test. This invention can simultaneously test multiple operating conditions, and by utilizing the in-phase parallel current generator in conjunction with the three-phase current generator to test the current, it reduces the voltage of the three-phase inverter and improves testing efficiency.

Description

Technical Field

[0001] This invention relates to the field of converter valve technology, and in particular to a device and control method for simulating the operating conditions of a flexible DC converter valve. Background Technology

[0002] Currently, high-voltage flexible direct current transmission (VSC-HVDC) technology has become a bridge connecting vast offshore wind farms with onshore power grids. As the core of this system, the VSC-HVDC converter valve plays a decisive role in the reliable transmission of electricity due to its stability and efficiency. With its modular and flexible structure, scalability, and excellent harmonic suppression capabilities, it has been widely used in the offshore wind power sector. To ensure that the VSC-HVDC converter valve can withstand various challenges in actual operation, a comprehensive evaluation and testing of its core components—the sub-modules—has become an indispensable step.

[0003] Existing converter valve testing methods require building a complete converter valve model for testing, which is costly. Although they can perform operating condition tests on converter valve sub-modules, the number of operating condition tests is small, resulting in low testing efficiency. Summary of the Invention

[0004] This invention provides a device and control method for simulating the operating conditions of a flexible DC-DC converter valve, in order to accurately test the sub-modules of the flexible DC-DC converter valve, reduce testing costs, and improve testing efficiency.

[0005] To address the aforementioned technical problems, this invention provides a flexible DC converter valve operating condition simulation device, comprising: a three-phase current generator, a first control module, an intra-phase drag current generator, a measured module, and a second control module.

[0006] The three-phase current generator is connected to the first control module, the phase-to-phase current generator, and the electrical device under test.

[0007] The phase-to-phase current generator is electrically connected to the module under test; the second control module is electrically connected to the phase-to-phase current generator and the module under test.

[0008] This invention controls a three-phase current generator to generate different test currents through a first control module, and controls an intra-phase drag current generator to generate auxiliary current according to a second control module, thereby controlling the module under test to generate different operating conditions. This allows for simultaneous testing of the first and second bridge arm modules in the three-phase current generator, increasing the number of operating condition tests. At the same time, by using the intra-phase drag current generator in conjunction with the three-phase current generator test current, the voltage of the three-phase inverter is reduced.

[0009] Furthermore, the three-phase current generator includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, and a sixth transistor;

[0010] The first transistor and the second transistor are connected in series to form a first phase module;

[0011] The third transistor and the fourth transistor are connected in series to form a second phase module;

[0012] The fifth transistor and the sixth transistor are connected in series to form the third phase module;

[0013] The first phase module, the second phase module, and the third phase module are connected in parallel, and the first end of the first phase module, the second phase module, and the third phase module is connected to the positive terminal of the power supply, and the second end of the first phase module, the second phase module, and the third phase module is connected to the negative terminal of the power supply.

[0014] Furthermore, the three-phase current generator also includes six diodes, which are connected in parallel with the first transistor, the second transistor, the third transistor, the fourth transistor, the fifth transistor, and the sixth transistor, respectively.

[0015] Furthermore, the in-phase drag current generator includes a first drag current generator and a second drag current generator;

[0016] Both the first pair of drag current generators and the second pair of drag current generators are electrically connected to the module under test and the second control module; the first pair of drag current generators is electrically connected to the first phase module, the second pair of drag current generators is electrically connected to the second phase module, and the second pair of drag current generators is electrically connected to the ground wire.

[0017] Furthermore, both the first pair of current-carrying generators and the second pair of current-carrying generators are half-bridge inverter structures, each half-bridge inverter structure including two transistors connected in series with the power supply.

[0018] The connection point between the half-bridge inverter structure and the three-phase current generator is located between two transistors.

[0019] Furthermore, the module under test includes a first module under test and a second module under test;

[0020] The first module under test is electrically connected to the first pair of current generators and the second phase module, and the first module under test is electrically connected to the ground wire.

[0021] The second module under test is electrically connected to the second pair of drag current generators and the third phase module.

[0022] Furthermore, both the first and second modules under test are half-bridge power modules, each comprising two transistors and one capacitor, with the two transistors connected in series with the power supply.

[0023] The connection point between the half-bridge power module and the three-phase current generator is located between two transistors.

[0024] The negative terminal of the capacitor of the first module under test is connected to the positive terminal of the power supply of the first pair of current generators.

[0025] The negative terminal of the capacitor of the second module under test is connected to the positive terminal of the power supply of the second pair of current generators.

[0026] Furthermore, a filter inductor is provided between the three-phase current generator and the module under test, and a filter inductor is provided between the three-phase current generator and the phase-to-phase current generator.

[0027] Secondly, the present invention provides a control method for a flexible DC converter valve operating condition simulation device, comprising:

[0028] The first control module generates a first drive signal and inputs the first drive signal into the three-phase current generator to control the three-phase current generator to generate a first test current.

[0029] The second control module generates a second drive signal and inputs the second drive signal into the phase-to-phase current generator to control the phase-to-phase current generator to generate a second test current.

[0030] Several operating conditions are generated based on the module under test, and the operating conditions generated by the module under test are simulated and tested based on the first test current and the second test current.

[0031] Furthermore, the step of generating a second drive signal according to the second control module and inputting the second drive signal into the phase-to-phase current generator to control the phase-to-phase current generator to generate a second test current includes:

[0032] A modulation wave is generated according to a preset operating condition, and a second driving signal is generated according to the modulation wave.

[0033] The second drive signal is simultaneously input to the module under test and the phase-to-phase current generator, so that the second control module generates a second test current, so that the module under test simulates a preset operating condition. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of a flexible DC converter valve operating condition simulation device provided in one embodiment of the present invention;

[0035] Figure 2 This is another structural schematic diagram of a flexible DC converter valve operating condition simulation device provided in an embodiment of the present invention;

[0036] Figure 3 This is a schematic diagram of a first bridge arm control module provided in an embodiment of the present invention. Detailed Implementation

[0037] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0038] The terms "first" and "second," etc., in the specification, claims, and drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or apparatus.

[0039] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0040] Example 1

[0041] See Figure 1 , Figure 1 This is a schematic diagram of a flexible DC-DC converter valve operating condition simulation device provided in one embodiment of the present invention. The flexible DC-DC converter valve operating condition simulation device provided in this embodiment includes: a three-phase current generator, a first control module, an in-phase countercurrent generator, a measured module, and a second control module;

[0042] The three-phase current generator is connected to the first control module, the phase-to-phase current generator, and the electrical device under test.

[0043] The phase-to-phase current generator is electrically connected to the module under test; the second control module is electrically connected to the phase-to-phase current generator and the module under test.

[0044] Please refer to Figure 2 , Figure 2This is another structural schematic diagram of a flexible DC converter valve operating condition simulation device provided in an embodiment of the present invention.

[0045] In this embodiment, the three-phase current generator includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, and a sixth transistor;

[0046] The first transistor and the second transistor are connected in series to form a first phase module;

[0047] The third transistor and the fourth transistor are connected in series to form a second phase module;

[0048] The fifth transistor and the sixth transistor are connected in series to form the third phase module;

[0049] The first phase module, the second phase module, and the third phase module are connected in parallel, and the first end of the first phase module, the second phase module, and the third phase module is connected to the positive terminal of the power supply, and the second end of the first phase module, the second phase module, and the third phase module is connected to the negative terminal of the power supply.

[0050] In this embodiment, a three-phase two-level inverter structure is adopted, and the DC side is powered by a DC voltage source. The test current of the upper bridge arm test module and the lower bridge arm test module is generated by the line voltage of the two phases.

[0051] In this embodiment, the three-phase current generator consists of six power transistors or power MOSFETs, divided into upper and lower groups, each containing three transistors connected in parallel. Under sinusoidal pulse width modulation (SPWM) control, by timely triggering the transistors, the DC input voltage can be converted into a controllable three-phase AC output voltage.

[0052] In this embodiment, the three-phase current generator adopts a three-phase two-level inverter structure, and the DC side is powered by a DC voltage source. The test current of the test module is generated by the line voltage of the two phases.

[0053] As a specific example of an embodiment of the present invention, the transistors are IGBTs (Insulated Gate Bipolar Transistors), and six IGBTs form a three-phase bridge inverter circuit. With proper PWM signal control, the three-phase bridge inverter circuit can generate a three-phase AC voltage related to the amplitude and frequency of the input DC voltage. During the inversion process, the trigger transistors are turned on, forming a switching control of the DC voltage, thereby achieving control of the output AC voltage.

[0054] In this embodiment, the three-phase current generator further includes six diodes, which are connected in parallel with the first transistor, the second transistor, the third transistor, the fourth transistor, the fifth transistor, and the sixth transistor, respectively.

[0055] In this embodiment, six IGBTs form three parallel loops. Each loop includes two IGBTs connected in series. Taking an N-channel IGBT as an example, the collector of the first IGBT is connected to the positive terminal of the power supply, the emitter of the first IGBT is connected to the collector of the second IGBT, and the collector of the second IGBT is connected to the first IGBT. The connection point between the first IGBT and the second IGBT is used as the voltage output point.

[0056] In this embodiment, the in-phase drag current generator includes a first drag current generator and a second drag current generator;

[0057] Both the first pair of drag current generators and the second pair of drag current generators are electrically connected to the module under test and the second control module; the first pair of drag current generators is electrically connected to the first phase module, the second pair of drag current generators is electrically connected to the second phase module, and the second pair of drag current generators is electrically connected to the ground wire.

[0058] In this embodiment, the module under test includes a first module under test and a second module under test;

[0059] The first module under test is electrically connected to the first pair of current generators and the second phase module, and the first module under test is electrically connected to the ground wire.

[0060] The second module under test is electrically connected to the second pair of drag current generators and the third phase module.

[0061] In this embodiment, the six transistors in the three-phase current generator are grouped into pairs of three to form complementary switches, which are respectively connected between the three-phase power supply. The three-phase current generator is divided into a first bridge arm module and a second bridge arm module. The first bridge arm module is tested based on the first pair of current generators and the first test module, and the second bridge arm module is tested based on the second pair of current generators and the second test module.

[0062] In this embodiment, both the first pair of current-carrying generators and the second pair of current-carrying generators are half-bridge inverter structures. The half-bridge inverter structure includes two transistors, which are connected in series with the power supply.

[0063] The connection point between the half-bridge inverter structure and the three-phase current generator is located between two transistors.

[0064] In this embodiment, the transistors in the half-bridge inverter structure are also configured as IGBT transistors.

[0065] In this embodiment, the first pair of drag current generators and the second pair of drag current generators adopt a half-bridge inverter structure. The DC side is powered by a DC voltage source, and its voltage Vs is equal to the DC component of the DC side capacitor voltage udc of the first and second modules under test. It is used to generate pulse voltage to cancel the distortion of the test current caused by the module under test and to assist the three-phase current generator in generating the test current.

[0066] In this embodiment, both the first module under test and the second module under test are half-bridge power modules. The half-bridge power module includes two transistors and one capacitor, and the two transistors are connected in series with the power supply.

[0067] The connection point between the half-bridge power module and the three-phase current generator is located between two transistors.

[0068] The negative terminal of the capacitor of the first module under test is connected to the positive terminal of the power supply of the first pair of current generators.

[0069] The negative terminal of the capacitor of the second module under test is connected to the positive terminal of the power supply of the second pair of current generators.

[0070] In this embodiment, the module under test is a half-bridge power module of a flexible DC converter valve, and the transistors of the half-bridge power module are also set as IGBT transistors. Through the first and second modules under test, the first and second bridge arm modules of the three-phase current generator can be tested simultaneously under two operating conditions.

[0071] In this embodiment, a filter inductor is provided between the three-phase current generator and the module under test, and a filter inductor is provided between the three-phase current generator and the phase-to-phase current generator.

[0072] In this embodiment, by adjusting the impedance characteristics of the current through the filter inductor, the passage of high-frequency signals can be restricted while low-frequency signals are allowed to pass through, so as to smoothly output AC voltage and reduce high-frequency noise and harmonics in the output waveform. This helps to improve the quality of the output current and reduce the impact on the load.

[0073] This invention also provides a control method for a flexible DC-DC converter valve operating condition simulation device, applied to such a device, comprising:

[0074] The first control module generates a first drive signal and inputs the first drive signal into the three-phase current generator to control the three-phase current generator to generate a first test current.

[0075] The second control module generates a second drive signal and inputs the second drive signal into the phase-to-phase current generator to control the phase-to-phase current generator to generate a second test current.

[0076] Several operating conditions are generated based on the module under test, and the operating conditions generated by the module under test are simulated and tested based on the first test current and the second test current.

[0077] In this embodiment, the current sampling value and the current reference value are input into the first control module so that the first module generates a first drive signal, thereby controlling the conduction and disconnection of the transistors in the three-phase current generator to adjust the test current generated by the three-phase current generator.

[0078] In this embodiment, the step of generating a second drive signal according to the second control module and inputting the second drive signal into the phase-to-phase current generator to control the phase-to-phase current generator to generate a second test current includes:

[0079] A modulation wave is generated according to a preset operating condition, and a second driving signal is generated according to the modulation wave.

[0080] The second drive signal is simultaneously input to the module under test and the phase-to-phase current generator, so that the second control module generates a second test current, so that the module under test simulates a preset operating condition.

[0081] In this embodiment, the second control module includes a first bridge arm control module and a second bridge arm control module. The first bridge arm control module is used to generate drive signals for a first pair of current generators and a first module under test to test the first bridge arm module in the three-phase current generator. The second bridge arm control module is used to generate drive signals for a second pair of current generators and a second module under test to test the second bridge arm module in the three-phase current generator.

[0082] In this embodiment, taking the first bridge arm control module as an example, in the first bridge arm control module, the first pair of drag current generators and the first test module have the same drive signal, which is used to eliminate the current distortion caused by the port voltage of the first test module.

[0083] As a specific example of an embodiment of the present invention, please refer to Figure 3 Figure 3 This is a schematic diagram of a first bridge arm control module provided in an embodiment of the present invention.

[0084] In this embodiment, the difference between the capacitor voltage sample value udc of the first bridge arm submodule group and its DC reference value Udcref is input to the PI controller. The output of the PI controller is multiplied by the sign function value of the test current sample value io to obtain the output of the balance control. After being superimposed with the reference modulation wave of the target flexible DC converter valve system, the final modulation wave um is obtained. Finally, after PWM modulation, a switching sequence, i.e., the drive signal, is generated shared by the first module under test and the first pair of drag current generators.

[0085] In this embodiment, the second bridge arm control module has the same settings and control process as the first bridge arm control module.

[0086] In this embodiment, the same switching sequence as the corresponding current generator, i.e. the module under test, is used to synchronously cancel the distortion effect of the port voltage of the module under test on the test current, thereby assisting the three-phase current generator in controlling the test current and reducing the power supply voltage requirement of the three-phase current generator.

[0087] In this embodiment, the first control module controls the three-phase current generator to generate different test currents, and the second control module controls the phase-to-phase current generator to generate auxiliary currents, thereby controlling the module under test to generate different operating conditions. This allows for simultaneous testing of the first and second bridge arm modules in the three-phase current generator, increasing the number of operating condition tests. At the same time, the phase-to-phase current generator is used in conjunction with the three-phase current generator to test the voltage of the three-phase inverter, reducing the voltage of the three-phase inverter.

[0088] In this embodiment of the invention, a multi-device access platform processing device is also provided, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the above-described multi-device access platform processing method.

[0089] In this embodiment of the invention, a computer-readable storage medium is also provided, which includes a stored computer program, wherein the computer program controls the device where the computer-readable storage medium is located to execute the above-described multi-device access platform processing method when it is running.

[0090] For example, a computer program can be divided into one or more modules, one or more of which are stored in memory and executed by a processor to perform the present invention. The one or more modules can be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program in a multi-device access platform processing device.

[0091] The multi-device access platform processing device can be a computing device such as a desktop computer, laptop, handheld computer, or cloud server. The multi-device access platform processing device may include, but is not limited to, a processor, memory, and a display. Those skilled in the art will understand that the above components are merely examples of the multi-device access platform processing device and do not constitute a limitation on the multi-device access platform processing device. It may include more or fewer components than the specified components, or a combination of certain components, or different components. For example, the multi-device access platform processing device may also include input / output devices, network access devices, buses, etc.

[0092] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the multi-device access platform processing device, connecting all parts of the multi-device access platform processing device through various interfaces and lines.

[0093] The memory can be used to store computer programs and / or modules. The processor, by running or executing the computer programs and / or modules stored in the memory, and by accessing data stored in the memory, realizes various functions of the multi-device access platform processing device. The memory can mainly include a program storage area and a data storage area. The program storage area can store the operating system, at least one application program required for a function (such as sound playback function, text conversion function, etc.), etc.; the data storage area can store data created according to the use of the mobile phone (such as audio data, text message data, etc.). In addition, the memory can include high-speed random access memory, and can also include non-volatile memory, such as hard disk, RAM, plug-in hard disk, smart memory card (SMC), secure digital card (SD) card, flash card, at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0094] In this invention, modules for processing multi-device access platforms, if implemented as software functional units and sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. Computer-readable media can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. Those skilled in the art can understand and implement this invention without any inventive effort.

[0095] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A device for simulating the operating conditions of a flexible DC converter valve, characterized in that, include: Three-phase current generator, first control module, phase-to-phase current generator, measured module and second control module; The three-phase current generator is connected to the first control module, the phase-to-phase current generator, and the electrical device under test. The phase-to-phase current generator is electrically connected to the module under test; the second control module is electrically connected to the phase-to-phase current generator and the module under test. The phase-to-phase current generator includes a first pair of current generators and a second pair of current generators; both the first pair of current generators and the second pair of current generators are electrically connected to the module under test and the second control module; the second pair of current generators is electrically connected to the ground wire. Both the first pair of current generators and the second pair of current generators are half-bridge inverter structures. The half-bridge inverter structure includes two transistors. The DC side of the half-bridge inverter structure is powered by a DC voltage source to generate pulse voltages to cancel the distortion caused by the module under test to the test current and to assist the three-phase current generator in generating the test current. The two transistors are connected in series with the DC voltage source. The connection point between the half-bridge inverter structure and the three-phase current generator is located between two transistors.

2. The flexible DC converter valve operating condition simulation device as described in claim 1, characterized in that, The three-phase current generator includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, and a sixth transistor; The first transistor and the second transistor are connected in series to form a first phase module; The third transistor and the fourth transistor are connected in series to form a second phase module; The fifth transistor and the sixth transistor are connected in series to form the third phase module; The first phase module, the second phase module, and the third phase module are connected in parallel, and the first end of the first phase module, the second phase module, and the third phase module is connected to the positive terminal of the power supply, and the second end of the first phase module, the second phase module, and the third phase module is connected to the negative terminal of the power supply.

3. The flexible DC converter valve operating condition simulation device as described in claim 2, characterized in that, The three-phase current generator also includes six diodes, which are connected in parallel with the first transistor, the second transistor, the third transistor, the fourth transistor, the fifth transistor, and the sixth transistor, respectively.

4. The flexible DC converter valve operating condition simulation device as described in claim 3, characterized in that, The first pair of drag current generators is electrically connected to the first phase module, and the second pair of drag current generators is electrically connected to the second phase module.

5. The flexible DC converter valve operating condition simulation device as described in claim 4, characterized in that, The module under test includes a first module under test and a second module under test; The first module under test is electrically connected to the first pair of current generators and the second phase module, and the first module under test is electrically connected to the ground wire. The second module under test is electrically connected to the second pair of drag current generators and the third phase module.

6. The flexible DC converter valve operating condition simulation device as described in claim 5, characterized in that, Both the first module under test and the second module under test are half-bridge power modules. The half-bridge power module includes two transistors and one capacitor, and the two transistors and the capacitor are connected in series. The connection point between the half-bridge power module and the three-phase current generator is located between two transistors. The negative terminal of the capacitor of the first module under test is connected to the positive terminal of the DC voltage source of the first pair of current generators; The negative terminal of the capacitor of the second module under test is connected to the positive terminal of the DC voltage source of the second pair of current generators.

7. The flexible DC converter valve operating condition simulation device as described in claim 6, characterized in that, A filter inductor is provided between the three-phase current generator and the module under test, and a filter inductor is provided between the three-phase current generator and the phase-to-phase current generator.

8. A control method for a flexible DC converter valve operating condition simulation device, characterized in that, A device for simulating the operating conditions of a flexible DC converter valve as described in any one of claims 1 to 7, comprising: The first control module generates a first drive signal and inputs the first drive signal into the three-phase current generator to control the three-phase current generator to generate a first test current. The second control module generates a second drive signal and inputs the second drive signal into the phase-to-phase current generator to control the phase-to-phase current generator to generate a second test current. Several operating conditions are generated based on the module under test, and the operating conditions generated by the module under test are simulated and tested based on the first test current and the second test current.

9. The control method for a flexible DC converter valve operating condition simulation device as described in claim 8, characterized in that, The step of generating a second drive signal according to the second control module and inputting the second drive signal into the phase-to-phase current generator to control the phase-to-phase current generator to generate a second test current includes: A modulation wave is generated according to a preset operating condition, and a second driving signal is generated according to the modulation wave. The second drive signal is simultaneously input to the module under test and the phase-to-phase current generator, so that the second control module generates a second test current, so that the module under test simulates a preset operating condition.

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