Converter valve operation test loop system and secondary circulating current regulation method and device

Abstract

The application belongs to the field of converter valve test, and discloses a converter valve operation test loop system and a secondary circulating current adjusting method and device. The system comprises a mode one for determining the number of input power modules of a tested valve section; and a mode two for determining the number of input power modules of a tested valve section. In the mode one, the number of input power modules of the tested valve section is equal to [modulation voltage divided by power module voltage rating of the tested valve section]. In the mode two, the number of input power modules of the tested valve section is equal to [modulation voltage divided by mixed power module voltage value], and the mixed power module voltage value is equal to m×real-time voltage average value of each power module of the tested valve section+(1-m)×power module voltage rating of the tested valve section, and 0≤m≤1. The content of the secondary circulating current is adjusted through the proportional coefficient m, the amplitude of the secondary circulating current is effectively adjusted under the condition that the direct current and the fundamental current amplitude fluctuate slightly, the actual demand of circulating current control in the valve section operation test is met, and the test precision is improved.

Description

Technical Field

[0001] This invention belongs to the field of converter valve testing, and relates to a converter valve operation test circuit system and a secondary circulation adjustment method and device. Background Technology

[0002] Flexible HVDC (HVDC flexible) is a new generation of high-voltage direct current transmission technology composed of fully controlled power electronic devices. It features independent control of active and reactive power, no commutation failure issues, the ability to supply power to passive networks, and good harmonic performance, making it suitable for applications such as distributed renewable energy grid connection, asynchronous interconnection of AC grids, and power supply to weak or isolated networks. Compared to two-level and three-level converters, modular multi-level converters (MMCs) offer advantages such as suitability for high-voltage, high-capacity transmission, low power device losses, and high waveform quality. The introduction of this topology has greatly promoted the engineering application of flexible HVDC technology. The MMC converter valve is a core component of a flexible HVDC transmission system, and its safety and reliability directly affect the reliability of the flexible HVDC project. Before the MMC converter valve is put into formal operation, type tests, including insulation tests and operational tests, are required. The valve section operational test verifies the operating characteristics of key components of the converter valve under actual operating conditions using standard test conditions.

[0003] The operational test circuit mainly consists of a test valve section, a valve section under test, a power supply circuit, and a load inductor. Both the test valve section and the valve section under test are composed of n power modules connected in series. Each power module in the test valve section is connected to the power supply circuit, and the test valve section and the valve section under test are connected through the load inductor. The power supply circuit is mainly used to charge the test valve section and the valve section under test during the initial stage of the test, and to replenish the electrical energy consumed by the power modules and the load during the test.

[0004] The valve section test current, which needs to be consistent with the engineering specifications, includes three parts: DC current, fundamental current, and secondary circulating current. While the DC current and fundamental current are relatively easy to adjust to obtain target values, the secondary circulating current is difficult to accurately determine due to its coupling with the DC current and fundamental current, thus affecting test accuracy. Currently, the test valve section and the valve section under test use the same modulation method, adjusting the DC component, fundamental component, and secondary circulating current values ​​through the angle difference between the modulation waves. Independent adjustment of the secondary circulating current is not possible. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art, which is that the secondary circulation cannot be independently adjusted in the operation test of the converter valve, resulting in low test accuracy. This invention provides a converter valve operation test circuit system and a method and device for adjusting the secondary circulation.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] In a first aspect, the present invention provides a method for adjusting the secondary circulating flow during operation testing of a converter valve, comprising:

[0008] The number of power modules in the tested valve section is determined using method one.

[0009] The number of power modules to be put into operation in the test valve section is determined by method two;

[0010] Among them, Method 1: The number of power modules put into the test valve section = [modulation voltage divided by the rated voltage of the power module of the test valve section]; Method 2: The number of power modules put into the auxiliary test valve section = [modulation voltage divided by the voltage value of the mixed power module], the voltage value of the mixed power module = m × the average real-time voltage of each power module of the auxiliary test valve section + (1-m) × the rated voltage of the power module of the auxiliary test valve section; where 0≤m≤1, the symbol [] indicates rounding to the nearest integer; and the number of power modules put into the test valve section is not greater than the total number of power modules of the test valve section, and the number of power modules put into the auxiliary test valve section is not greater than the total number of power modules of the auxiliary test valve section;

[0011] When it is necessary to reduce the secondary circulating current content, increase the proportionality coefficient m;

[0012] When it is necessary to increase the secondary circulating current content, reduce the proportionality factor m.

[0013] Optional, also includes:

[0014] Obtain the current direction of the valve section under test and the real-time voltage of each power module;

[0015] When the current direction of the valve section under test is positive, the power modules to be put into the valve section under test are determined according to the number of power modules put into the valve section under test and the real-time voltage of each power module in the valve section under test, in order of real-time voltage from low to high, and the power modules to be put into the valve section under test are put into operation.

[0016] When the current direction of the valve section under test is negative, the power modules to be put into the valve section under test are determined according to the number of power modules put into the valve section under test and the real-time voltage of each power module in the valve section under test, in descending order of real-time voltage, and then the power modules to be put into the valve section under test are put into operation.

[0017] Optionally, when the power module to be put into the valve section under test is put into operation, if the power module to be put into the valve section under test is a full-bridge power module, the power module to be put into the valve section under test is set to the positive input state.

[0018] Optional, also includes:

[0019] Obtain the current direction of the test valve section and the real-time voltage of each power module;

[0020] When the current direction of the test valve section is positive, the power modules to be put into the test valve section are determined according to the number of power modules put into the test valve section and the real-time voltage of each power module in the test valve section, in order of real-time voltage from low to high, and the power modules to be put into the test valve section are put into operation.

[0021] When the current direction of the test valve section is negative, the power modules to be put into the test valve section are determined according to the number of power modules put into the test valve section and the real-time voltage of each power module in the test valve section, in descending order of real-time voltage, and then the power modules to be put into the test valve section are put into operation.

[0022] Optionally, when the power module to be put into the test valve section is put into operation, if the power module to be put into the test valve section is a full-bridge power module, the power module to be put into the test valve section is set to the positive operation state.

[0023] In a second aspect, the present invention provides a secondary circulating flow regulating device for a converter valve operation test, comprising:

[0024] The test valve section activation determination module is used to determine the number of power modules activated for the test valve section through method one.

[0025] The module for determining the input of the test valve section is used to determine the number of input power modules of the test valve section through method two; wherein, method one: the number of input power modules of the test valve section = [modulation voltage divided by the rated voltage of the power module of the test valve section]; method two: the number of input power modules of the test valve section = [modulation voltage divided by the voltage value of the mixed power module], the voltage value of the mixed power module = m × the average real-time voltage of each power module of the test valve section + (1-m) × the rated voltage of the power module of the test valve section; wherein, 0≤m≤1, the symbol [] indicates rounding to the nearest integer; and the number of input power modules of the test valve section is not greater than the total number of power modules of the test valve section, and the number of input power modules of the test valve section is not greater than the total number of power modules of the test valve section;

[0026] The adjustment module is used to increase the proportional coefficient m when it is necessary to reduce the secondary circulating current content, and to decrease the proportional coefficient m when it is necessary to increase the secondary circulating current content.

[0027] Optionally, it also includes: a test valve segment activation control module, used to acquire the current direction of the test valve segment and the real-time voltage of each power module; when the current direction of the test valve segment is positive, the power modules to be activated in the test valve segment are determined according to the number of activated power modules in the test valve segment and the real-time voltage of each power module in the test valve segment, in order of real-time voltage from low to high, and the power modules to be activated in the test valve segment are activated; when the current direction of the test valve segment is negative, the power modules to be activated in the test valve segment are determined according to the number of activated power modules in the test valve segment and the real-time voltage of each power module in the test valve segment, in order of real-time voltage from high to low, and the power modules to be activated in the test valve segment are activated.

[0028] Optionally, it also includes: a test valve section activation control module, used to acquire the current direction of the test valve section and the real-time voltage of each power module; when the current direction of the test valve section is positive, the power modules to be activated in the test valve section are determined according to the number of activated power modules in the test valve section and the real-time voltage of each power module in the test valve section, in order of real-time voltage from low to high, and the power modules to be activated in the test valve section are activated; when the current direction of the test valve section is negative, the power modules to be activated in the test valve section are determined according to the number of activated power modules in the test valve section and the real-time voltage of each power module in the test valve section, in order of real-time voltage from high to low, and the power modules to be activated in the test valve section are activated.

[0029] In a third aspect, the present invention provides a converter valve operation test circuit system, including a power supply circuit, a test valve section, a load inductor, a test valve section, and the aforementioned converter valve operation test secondary circulating current adjustment device;

[0030] The power supply circuit is connected to the test valve section. One end of the test valve section is connected to one end of the test valve section through the load inductor, and the other end is connected to the other end of the test valve section. The secondary circulating flow regulating device for the converter valve operation test is connected to each power module of the test valve section and each power module of the test valve section.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] This invention discloses a secondary circulating current adjustment method for converter valve operation testing. For the valve section under test, the rated voltage of the power module is used as the benchmark for calculating the number of power modules to be input, i.e., the number of power modules to be input equals [modulation voltage divided by the rated voltage of the power module of the valve section under test]. For the accompanying valve section, the mixed power module voltage value is used as the benchmark for calculating the number of power modules to be input, i.e., the number of power modules to be input in the accompanying valve section equals [modulation voltage divided by the mixed power module voltage value]. The mixed power module voltage value is obtained by superimposing the real-time average voltage of each power module in the accompanying valve section and the rated voltage of the power module of the accompanying valve section through a weighting coefficient. By using the mixed power module voltage method, the amplitude of the secondary circulating current can be effectively adjusted when the amplitude fluctuations of the DC current and the fundamental current are small, realizing independent adjustment of the secondary circulating current. This allows the secondary circulating current to be adjusted to an accurate value, meeting the actual needs of circulating current control in valve section operation testing, thereby improving the test accuracy. Attached Figure Description

[0033] Figure 1 This is a schematic diagram illustrating the principle of the secondary circulation adjustment method for the converter valve operation test according to an embodiment of the present invention.

[0034] Figure 2 This is a schematic diagram of the MMC topology according to an embodiment of the present invention.

[0035] Figure 3 This is a topology diagram of a half-bridge power module according to an embodiment of the present invention.

[0036] Figure 4 This is a topology diagram of a full-bridge power module according to an embodiment of the present invention.

[0037] Figure 5 This is a structural block diagram of the secondary circulation regulating device for the operation test of the converter valve according to an embodiment of the present invention.

[0038] Figure 6 This is a schematic diagram of the converter valve operation test circuit system according to an embodiment of the present invention. Detailed Implementation

[0039] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0040] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0041] The present invention will now be described in further detail with reference to the accompanying drawings:

[0042] See Figure 1 In one embodiment of the present invention, by analyzing the actual requirements of circulating current control in valve section operation test, a method for adjusting secondary circulating current in converter valve operation test is provided, which can effectively adjust the amplitude of secondary circulating current when the amplitude fluctuations of DC current and fundamental current are small.

[0043] Specifically, the secondary circulating current adjustment method for the converter valve operation test includes the following steps: determining the number of power modules in the tested valve section using method one; determining the number of power modules in the auxiliary valve section using method two; wherein, method one: number of power modules in the tested valve section = [modulation voltage divided by the rated voltage of the power modules in the tested valve section]; method two: number of power modules in the auxiliary valve section = [modulation voltage divided by the voltage value of the mixed power modules], the voltage value of the mixed power modules = m × the average real-time voltage of each power module in the auxiliary valve section + (1-m) × the rated voltage of the power modules in the auxiliary valve section; wherein, 0≤m≤1, the symbol [] indicates rounding; and the number of power modules in the tested valve section is not greater than the total number of power modules in the tested valve section, and the number of power modules in the auxiliary valve section is not greater than the total number of power modules in the auxiliary valve section; when it is necessary to reduce the secondary circulating current content, the proportional coefficient m is increased; when it is necessary to increase the secondary circulating current content, the proportional coefficient m is decreased.

[0044] The valve section operation test verifies the operating characteristics of key components of the converter valve under actual operating conditions using standard test conditions. The operation test circuit mainly consists of a test valve section, a valve section under test, a power supply circuit, and a load inductor. Both the test valve section and the valve section under test are composed of n power modules (the number of n can be determined according to engineering test requirements, generally not exceeding 8) connected in series. Each power module in the test valve section is connected to the power supply circuit, and the test valve section and the valve section under test are connected through the load inductor. The power supply circuit is mainly used to charge the test valve section and the valve section under test during the initial stage of the test, and to replenish the electrical energy consumed by the power modules and the load during the test.

[0045] At the beginning of the power module bypass test, the power module capacitor in the test valve section is first charged by the power supply circuit. When the voltage of the power module capacitor in the test valve section reaches the rated value, the test valve section is pulse-charged to the valve section under test, causing the voltage of the power module capacitor in the valve section under test to rise in a stepwise manner.

[0046] Once the voltage of the power module capacitor in the tested valve section reaches its rated value, all power modules are unlocked, and the accompanying valve section and the tested valve section operate according to their respective modulation waves. By adjusting the amplitude and phase of the modulation wave, the voltage of the power module and the valve section current in the tested valve section can be made basically consistent with the actual engineering, thereby achieving the purpose of verifying the stress resistance capability of the power modules. However, the valve section test current that needs to be consistent with the engineering includes three parts: DC current, fundamental current, and secondary circulating current. Among these three parts, the DC current and fundamental current are relatively easy to adjust to obtain target values, while the secondary circulating current is difficult to obtain an accurate value due to its coupling with the DC current and fundamental current, thus affecting the test accuracy.

[0047] To effectively adjust the amplitude of the secondary circulating current under conditions of relatively small fluctuations in the amplitudes of the DC current and fundamental current, this invention provides a secondary circulating current adjustment method for converter valve operation testing. In the valve section under test, the rated voltage of the power module is used as the benchmark for calculating the number of power modules to be engaged; that is, the number of power modules engaged equals the modulation voltage divided by the rated voltage of the power module. In the accompanying valve section, the voltage value of the hybrid module is used as the benchmark for calculating the number of power modules to be engaged; that is, the number of power modules engaged equals the modulation voltage divided by the voltage value of the hybrid module. The voltage value of the hybrid module consists of the average real-time voltage of the power module with a proportionality coefficient of m (0 ≤ m ≤ 1) and the rated voltage of the power module with a proportionality coefficient of (1-m).

[0048] Based on this design, the proportional coefficient m can be adjusted between 0 and 1 according to experimental needs. When m = 0, the secondary circulating current in the test circuit is at its maximum; as m gradually increases, the secondary circulating current content can be gradually reduced; when m = 1, the secondary circulating current content is at its minimum. This achieves independent adjustment of the secondary circulating current.

[0049] Figure 1 In the middle, F p F represents the modulation ratio of the test module. b Indicates the modulation ratio of the tested module, PWM represents pulse width modulation, U dc U represents the DC bias voltage. p U represents the amplitude of the interaction during the test. b P represents the amplitude of the subject's communication. b U represents the phase difference between two reference waves. dc / N u Vp represents the voltage of the capacitor, and V represents the voltage of the test module.b Indicates the voltage of the tested module

[0050] In principle, using a fixed modulation ratio introduces voltage fluctuations from the power module capacitors into the output voltage of either the test valve section or the valve under test, resulting in second and third harmonic components in the inductor AC voltage. Assuming the modulation ratio is related to the average voltage of all current power modules—that is, the modulation ratio is a given voltage divided by the average voltage of the power modules—the influence of the fundamental frequency and the second harmonic on the output voltage of the test valve section can be eliminated.

[0051] In the current modulation method, ignoring the effects of the power module's switching frequency and voltage equalization algorithm, the current modulation of each power module for both the test and the candidate is as follows: m p The modulation ratio is the same for both the interrogator and the subject modules:

[0052]

[0053] After calculation, the second and third harmonics of the AC voltage applied to the inductor are shown in equation (2):

[0054]

[0055] From equation (2), the second and third harmonic currents can be obtained. By rearranging the equations, it can be seen that the second harmonic current in the inductor current is related to the fundamental current, and the third harmonic current is related to both the fundamental and second harmonics, as shown in equation (3):

[0056]

[0057] To reduce the harmonic content in the inductor current without affecting the modulation method and electrical stress characteristics of the tested power module, the modulation method of the test module and the tested module as shown in equation (4) can be adopted. Where, u pc av The real-time average voltage of each power module in the test valve section is given by the modulation ratio F of the power module in the test valve section. pn It changes with the fluctuation of the power module capacitor, which can eliminate the harmonic current generated by the AC fluctuation of the power module capacitor voltage in the test valve section.

[0058]

[0059] Among them, F pn U represents the modulation ratio of the test module. dc Indicates the DC bias voltage, m p p represents the modulation ratio. b N represents the phase difference between two reference waves. u Indicates the number of power modules. denoted as the average voltage of all capacitors in the power module under test, and w represents the angular frequency.

[0060] The inductor current harmonics of the modulation method using equation (4) mainly come from the voltage fluctuation of the capacitor of the tested module. Therefore, the second and third harmonic components of the voltage applied to the load inductor can be obtained as shown in equation (5), and the harmonic current generated by the harmonic voltage is shown in equation (6).

[0061]

[0062]

[0063] Among them, u L2n u represents the second harmonic component of the voltage applied to the inductor. L3n I1 represents the third harmonic component of the voltage applied to the inductor, I2 represents the fundamental current, and m represents the second harmonic current. p p represents the modulation ratio. b C represents the phase difference between two reference waves. p Indicates the capacitance value of the power module capacitor, i l2n i represents the second inductor current. L3n L represents the third-order inductor current. c Indicates inductance.

[0064] Based on the above analysis, comparing equations (3) and (6), it can be seen that using equation (1) with a fixed modulation ratio will introduce the voltage fluctuation of the power module capacitor into the output voltage of the test or under-test valve section, resulting in the appearance of second and third harmonic components in the AC voltage of the inductor. However, using the modulation method of equation (4), the second and third harmonic currents in the inductor can be significantly reduced. That is, when the modulation ratio of the test valve section adopts the modulation method of equation (1), its harmonic current is the largest, which meets the second harmonic circulating current test condition of the flexible DC converter; when the modulation ratio of the test valve section adopts the modulation method of equation (4), the harmonic current content can be greatly reduced, which meets the low circulating current test condition of the flexible DC converter.

[0065] In one possible implementation, the secondary circulating current adjustment method for the converter valve operation test further includes: acquiring the current direction of the valve section under test and the real-time voltage of each power module; when the current direction of the valve section under test is positive, determining the power modules to be put into the valve section under test according to the number of power modules in the valve section under test and the real-time voltage of each power module in the valve section under test, in order of real-time voltage from low to high, and putting the power modules to be put into the valve section under test into operation; when the current direction of the valve section under test is negative, determining the power modules to be put into the valve section under test according to the number of power modules in the valve section under test and the real-time voltage of each power module in the valve section under test, in order of real-time voltage from high to low, and putting the power modules to be put into the valve section under test into operation.

[0066] Optionally, the secondary circulating current adjustment method for the converter valve operation test further includes: obtaining the current direction of the test valve section and the real-time voltage of each power module; when the current direction of the test valve section is positive, determining the power modules to be put into the test section according to the number of power modules put into the test valve section and the real-time voltage of each power module in the test valve section, in order of real-time voltage from low to high, and putting the power modules to be put into the test valve section into operation; when the current direction of the test valve section is negative, determining the power modules to be put into the test valve section according to the number of power modules put into the test valve section and the real-time voltage of each power module in the test valve section, in order of real-time voltage from high to low, and putting the power modules to be put into the test valve section into operation.

[0067] Specifically, when the power module required for the valve section under test is put into operation, if the power module required for the valve section under test is a full-bridge power module, the power module required for the valve section under test is set to the positive operation state. When the power module required for the auxiliary valve section is put into operation, if the power module required for the auxiliary valve section is a full-bridge power module, the power module required for the auxiliary valve section is set to the positive operation state.

[0068] Specifically, in practical applications, power modules that are not in use are in a disconnected state. After determining the number of power modules to be used, the power module to be used is determined based on the voltage ranking and current direction. For example, if the current direction is positive, it is charging the power module, so the power module with the lower capacitor voltage is used; if the current direction is negative, it is discharging the power module, so the power module with the higher capacitor voltage is used. In short, the power module voltage is kept within a certain range; if it is too high, it is discharged to lower it, and if it is too low, it is charged to raise it.

[0069] See Figures 2 to 4 MMC typically consists of three phase units, each phase containing upper and lower bridge arms. Each bridge arm is composed of several power modules connected in series. The power module type can be half-bridge, full-bridge, or a hybrid of half-bridge and full-bridge.

[0070] Among them, the half-bridge power module (HBSM) generally has three operating states:

[0071] 1) Blocked state: S1 and S2 are not conducting.

[0072] 2) Engagement state: S1 is on, S2 is off.

[0073] 3) Resection status: S1 is not conductive, S2 is conductive.

[0074] Full-bridge power modules (FBSMs) typically have four operating states:

[0075] 1) Blocked state: S1, S2, S3 and S4 are not conducting.

[0076] 2) Positive input state: Both S1 and S4 are on.

[0077] 3) Resection status: S1 and S2 are both conducting or S3 and S4 are both conducting.

[0078] 4) Negative input state: Both S2 and S3 are on.

[0079] The following are embodiments of the apparatus of the present invention, which can be used to execute embodiments of the method of the present invention. For details not disclosed in the apparatus embodiments, please refer to the embodiments of the method of the present invention.

[0080] See Figure 5 In another embodiment of the present invention, a secondary circulation adjustment device for a converter valve operation test is provided, which can be used to implement the above-mentioned secondary circulation adjustment method for a converter valve operation test. Specifically, it includes a test valve section input determination module, a companion valve section input determination module, and an adjustment module.

[0081] The test valve section input determination module is used to determine the number of input power modules for the test valve section using method one; the auxiliary test valve section input determination module is used to determine the number of input power modules for the auxiliary test valve section using method two; wherein, method one: number of input power modules for the test valve section = [modulation voltage divided by the rated voltage of the power modules of the test valve section]; method two: number of input power modules for the auxiliary test valve section = [modulation voltage divided by the voltage value of the mixed power modules], the voltage value of the mixed power modules = m × the average real-time voltage of each power module in the auxiliary test valve section + (1-m) × the rated voltage of the power modules in the auxiliary test valve section, 0≤m≤1; the adjustment module is used to increase the proportional coefficient m when it is necessary to reduce the secondary circulating current content; and to decrease the proportional coefficient m when it is necessary to increase the secondary circulating current content.

[0082] In one possible implementation, the secondary circulating current adjustment device for the converter valve operation test further includes: a test valve section activation control module, which is used to acquire the current direction of the test valve section and the real-time voltage of each power module; when the current direction of the test valve section is positive, the power modules to be activated in the test valve section are determined according to the number of activated power modules in the test valve section and the real-time voltage of each power module in the test valve section, in order of real-time voltage from low to high, and the power modules to be activated in the test valve section are activated; when the current direction of the test valve section is negative, the power modules to be activated in the test valve section are determined according to the number of activated power modules in the test valve section and the real-time voltage of each power module in the test valve section, in order of real-time voltage from high to low, and the power modules to be activated in the test valve section are activated.

[0083] In one possible implementation, the secondary circulating current adjustment device for the converter valve operation test further includes: a test valve section activation control module, which is used to acquire the current direction of the test valve section and the real-time voltage of each power module; when the current direction of the test valve section is positive, the power modules to be activated in the test valve section are determined according to the number of activated power modules in the test valve section and the real-time voltage of each power module in the test valve section, in order of increasing real-time voltage, and the power modules to be activated in the test valve section are activated; when the current direction of the test valve section is negative, the power modules to be activated in the test valve section are determined according to the number of activated power modules in the test valve section and the real-time voltage of each power module in the test valve section, in order of decreasing real-time voltage, and the power modules to be activated in the test valve section are activated.

[0084] See Figure 6 In another embodiment of the present invention, a converter valve operation test circuit system is provided, including a power supply circuit, a test valve section, a load inductor, a test valve section, and the aforementioned converter valve operation test secondary circulating current adjustment device; the power supply circuit is connected to the test valve section, one end of the test valve section is connected to one end of the test valve section through the load inductor, and the other end is connected to the other end of the test valve section; the converter valve operation test secondary circulating current adjustment device is connected to each power module of the test valve section and each power module of the test valve section.

[0085] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for adjusting the secondary circulating flow during the operation test of a converter valve, characterized in that, include: The number of power modules in the tested valve section is determined using method one. The number of power modules to be put into operation in the test valve section is determined by method two; Among them, Method 1: The number of power modules put into the test valve section = [modulation voltage divided by the rated voltage of the power module of the test valve section]; Method 2: The number of power modules put into the auxiliary test valve section = [modulation voltage divided by the voltage value of the mixed power module], the voltage value of the mixed power module = m × the average real-time voltage of each power module of the auxiliary test valve section + (1-m) × the rated voltage of the power module of the auxiliary test valve section; where 0≤m≤1, the symbol [] indicates rounding to the nearest integer; and the number of power modules put into the test valve section is not greater than the total number of power modules of the test valve section, and the number of power modules put into the auxiliary test valve section is not greater than the total number of power modules of the auxiliary test valve section; When it is necessary to reduce the secondary circulating current content, increase the proportionality coefficient m; When it is necessary to increase the secondary circulating current content, decrease the proportionality factor m; Also includes: Obtain the current direction of the valve section under test and the real-time voltage of each power module; When the current direction of the valve section under test is positive, the power modules to be put into the valve section under test are determined according to the number of power modules put into the valve section under test and the real-time voltage of each power module in the valve section under test, in order of real-time voltage from low to high, and the power modules to be put into the valve section under test are put into operation. When the current direction of the valve section under test is negative, the power modules to be put into the valve section under test are determined according to the number of power modules put into the valve section under test and the real-time voltage of each power module in the valve section under test, in descending order of real-time voltage, and the power modules to be put into the valve section under test are put into operation. Also includes: Obtain the current direction of the test valve section and the real-time voltage of each power module; When the current direction of the test valve section is positive, the power modules to be put into the test valve section are determined according to the number of power modules put into the test valve section and the real-time voltage of each power module in the test valve section, in order of real-time voltage from low to high, and the power modules to be put into the test valve section are put into operation. When the current direction of the test valve section is negative, the power modules to be put into the test valve section are determined according to the number of power modules put into the test valve section and the real-time voltage of each power module in the test valve section, in descending order of real-time voltage, and then the power modules to be put into the test valve section are put into operation.

2. The secondary circulation adjustment method for the converter valve operation test according to claim 1, characterized in that, When the power module to be put into the valve section under test is put into operation, if the power module to be put into the valve section under test is a full-bridge power module, the power module to be put into the valve section under test is set to the positive input state.

3. The secondary circulation adjustment method for the converter valve operation test according to claim 1, characterized in that, When the power module to be put into the test valve section is put into operation, if the power module to be put into the test valve section is a full-bridge power module, the power module to be put into the test valve section is set to the positive input state.

4. A secondary circulating flow regulating device for converter valve operation testing, characterized in that, include: The test valve section activation determination module is used to determine the number of power modules activated for the test valve section through method one; The accompanying valve section input determination module is used to determine the number of input power modules for the accompanying valve section through method two; Among them, Method 1: The number of power modules put into the test valve section = [modulation voltage divided by the rated voltage of the power module of the test valve section]; Method 2: The number of power modules put into the auxiliary test valve section = [modulation voltage divided by the voltage value of the mixed power module], the voltage value of the mixed power module = m × the average real-time voltage of each power module of the auxiliary test valve section + (1-m) × the rated voltage of the power module of the auxiliary test valve section; where 0≤m≤1, the symbol [] indicates rounding to the nearest integer; and the number of power modules put into the test valve section is not greater than the total number of power modules of the test valve section, and the number of power modules put into the auxiliary test valve section is not greater than the total number of power modules of the auxiliary test valve section; The adjustment module is used to increase the proportional coefficient m when it is necessary to reduce the secondary circulating current content, and to decrease the proportional coefficient m when it is necessary to increase the secondary circulating current content. It also includes: a test valve section activation control module, used to acquire the current direction of the test valve section and the real-time voltage of each power module; when the current direction of the test valve section is positive, the power modules to be activated in the test valve section are determined according to the number of activated power modules in the test valve section and the real-time voltage of each power module in the test valve section, in order of real-time voltage from low to high, and the power modules to be activated in the test valve section are activated; when the current direction of the test valve section is negative, the power modules to be activated in the test valve section are determined according to the number of activated power modules in the test valve section and the real-time voltage of each power module in the test valve section, in order of real-time voltage from high to low, and the power modules to be activated in the test valve section are activated. It also includes: a test valve section activation control module, used to acquire the current direction of the test valve section and the real-time voltage of each power module; when the current direction of the test valve section is positive, the power modules to be activated in the test valve section are determined according to the number of activated power modules in the test valve section and the real-time voltage of each power module in the test valve section, in order of real-time voltage from low to high, and the power modules to be activated in the test valve section are activated; when the current direction of the test valve section is negative, the power modules to be activated in the test valve section are determined according to the number of activated power modules in the test valve section and the real-time voltage of each power module in the test valve section, in order of real-time voltage from high to low, and the power modules to be activated in the test valve section are activated.

5. A test circuit system for a converter valve operation, characterized in that, Includes a power supply circuit, a test valve section, a load inductor, a test valve section, and the secondary circulating flow adjustment device for the converter valve operation test as described in claim 4; The power supply circuit is connected to the test valve section. One end of the test valve section is connected to one end of the test valve section through the load inductor, and the other end is connected to the other end of the test valve section. The secondary circulating flow regulating device for the converter valve operation test is connected to each power module of the test valve section and each power module of the test valve section.

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