Explosion-proof test circuit for flexible direct-current converter valve
By using an explosion-proof test circuit with an independent energy storage capacitor module and a trigger freewheeling module, fault energy is directly injected into the module under test, solving the problems of high testing costs and uncertain results in existing technologies. This achieves efficient and accurate explosion-proof performance evaluation and improves the reliability of flexible DC transmission.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-27
- Publication Date
- 2026-03-10
AI Technical Summary
Existing explosion-proof testing technologies for flexible DC converter valves suffer from high testing costs, large resource investment, complex software debugging, and strong uncertainty in results, making it difficult to accurately assess the protection performance of submodules under extreme fault conditions.
An explosion-proof test circuit employs an independent energy storage capacitor module, a trigger freewheeling module, and a high-speed recording module. It injects fault energy directly into the module under test through a large-capacity energy source. Combined with precise control and multi-dimensional data recording, it simulates extreme fault conditions to ensure the accuracy and reliability of the test.
The test process was simplified, costs and resource inputs were reduced, the accuracy and efficiency of the test were improved, the explosion-proof performance of the tested module was accurately reflected, and the reliability of flexible DC transmission was enhanced.
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Figure CN121633671A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of flexible direct current transmission, in particular to a flexible direct current converter valve explosion-proof test circuit. BACKGROUND
[0002] Voltage Source Converter based High Voltage Direct Current (VSC-HVDC) is a direct current transmission technology taking full control devices such as insulated gate bipolar transistors (IGBT) as core power devices. Compared with conventional direct current transmission (Line Commutated Converter High Voltage Direct Current, LCC-HVDC), VSC-HVDC has advantages in reactive power compensation capability, no need for support power, no commutation failure, and flexible power control.
[0003] However, the flexible direct current transmission technology is limited by the current-carrying capacity of the IGBT device. With the continuous improvement of transmission voltage level and capacity, the capacity and voltage level of the converter valve sub-module capacitor are also improved, which leads to a sharp increase in the short-circuit discharge energy of the capacitor under extreme fault conditions, and the short-circuit current borne by the sub-module increases significantly, which greatly enhances the destructiveness of the module. In order to improve the reliability of the converter valve, it is required that the converter valve sub-module should have long-term current-carrying capacity even if it fails under extreme conditions, and should not affect the normal operation of other sub-modules. Therefore, the flexible direct current converter valve needs to be verified through explosion-proof test (bypass refusal test) to confirm whether the sub-module meets the application requirements under this extreme condition. SUMMARY
[0004] The purpose of the embodiments of the present application is to provide a flexible direct current converter valve explosion-proof test circuit, which can effectively improve the accuracy of the detection of the protection performance of the flexible direct current converter valve, thereby improving the reliability of the flexible direct current transmission.
[0005] To achieve the above-mentioned purpose, a first aspect of the embodiments of the present application provides a flexible direct current converter valve explosion-proof test circuit, comprising: An energy storage capacitor module, which is used to store large-capacity energy required for explosion-proof test; A trigger freewheeling module, which is electrically connected with the energy storage capacitor module, and is used to control the directional injection of energy of the energy storage capacitor module to a test module, so as to ensure triggering short-circuit discharge of the test module; A test module, which is electrically connected with the trigger freewheeling module, and comprises a test capacitor and a bridge arm composed of an insulated gate bipolar transistor and a diode, the bridge arm forming a current path for explosion-proof test; A high-speed recording module is electrically connected with the energy storage capacitor module and the test module, and is configured to synchronously record the voltage of the energy storage capacitor module, the voltage of the test capacitor, the port voltage of the test module, the waveform of the charging current injected into the test module, and the waveform of the anti-explosion current of the test module, and key time points, including the triggering time of the trigger and freewheeling module.
[0006] Compared with the prior art, the flexible DC converter valve anti-explosion test circuit provided by the embodiments of the present application has the advantages that: the energy storage capacitor module stores large-capacity energy to provide sufficient energy basis for simulating extreme fault scenarios; the trigger and freewheeling module precisely controls the directional injection of energy to ensure the reliable triggering of the short-circuit discharge scenario of the test module and improve the accuracy of the test; the bridge arm structure of the test module covers the test capacitor, IGBT and diode to form a complete current path, which can adapt to different characteristics of devices (whether the IGBT has long-term current-carrying capability); the high-speed recording module synchronously records the multi-dimensional electrical parameters (voltage and current waveforms) and key time points to comprehensively capture the data of the test process and provide accurate basis for analyzing the anti-explosion performance of the test module. In summary, the circuit discards the valve segment platform and the drag mode in the prior art, directly injects fault energy into the test module through an independent controllable large-capacity energy source, accurately simulates extreme fault conditions (bypass refusal leads to capacitor overvoltage discharge), and can effectively improve the accuracy of the detection of the protection performance of the flexible DC converter valve, thereby improving the reliability of the flexible DC power transmission.
[0007] In some embodiments, the test module has a first port and a second port, the first port is electrically connected with one end of the trigger and freewheeling module, and the second port is electrically connected with the other end of the trigger and freewheeling module. When the insulated gate bipolar transistor of the test module has long-term current-carrying capability, the test module includes a first insulated gate bipolar transistor, a first diode, a second insulated gate bipolar transistor, a second diode, a test capacitor, a third resistor, a first insulating block, a second insulating block, a third insulating block, and a first metal block. The collector of the first insulated gate bipolar transistor is electrically connected with one end of the test capacitor, the emitter of the first insulated gate bipolar transistor is electrically connected with the anode of the first diode, and the cathode of the first diode is reversely connected in parallel with the collector of the first insulated gate bipolar transistor. The collector of the second insulated gate bipolar transistor is electrically connected with the emitter of the first insulated gate bipolar transistor, the emitter of the second insulated gate bipolar transistor is electrically connected with the anode of the second diode, and the cathode of the second diode is reversely connected in parallel with the collector of the second insulated gate bipolar transistor. One end of the capacitor under test is electrically connected to the connection node between the collector of the first insulated gate bipolar transistor and the cathode of the first diode, and the other end of the capacitor under test is electrically connected to the connection node between the emitter of the second insulated gate bipolar transistor and the anode of the second diode. One end of the third resistor is electrically connected to one end of the capacitor under test, and the other end of the third resistor is electrically connected to the other end of the capacitor under test. One end of the first insulating block is connected to the collector of the first insulated gate bipolar transistor, and the other end of the first insulating block is connected to the second port; the second insulating block is connected in parallel with the first insulating block; one end of the first metal block is electrically connected to the other end of the first insulating block, and the other end of the first metal block is electrically connected to the emitter of the second insulated gate bipolar transistor; the third insulating block is connected in parallel with the first metal block.
[0008] In some embodiments, the test module has a first port and a second port, the first port being electrically connected to one end of the trigger current-continuing module and the second port being electrically connected to the other end of the trigger current-continuing module; When the insulated gate bipolar transistor of the test module does not have long-term current carrying capacity, the test module includes a first insulated gate bipolar transistor, a first diode, a third thyristor, a second insulated gate bipolar transistor, a fifth insulating block, a test capacitor, a third resistor, a sixth insulating block, a seventh insulating block, an eighth insulating block, and a second metal block. The first main electrode of the third thyristor is electrically connected to the second port, and the second main electrode of the third thyristor is electrically connected to the first port; The collector of the first insulated gate bipolar transistor is electrically connected to one end of the capacitor under test, the emitter of the first insulated gate bipolar transistor is electrically connected to the anode of the first diode, and the cathode of the first diode is connected in reverse parallel with the collector of the first insulated gate bipolar transistor. The collector of the second insulated gate bipolar transistor is electrically connected to the emitter of the first insulated gate bipolar transistor. The emitter of the second insulated gate bipolar transistor is connected to one end of the fifth insulating block, and the other end of the fifth insulating block is connected to the collector of the second insulated gate bipolar transistor. One end of the capacitor under test is electrically connected to the connection node between the collector of the first insulated gate bipolar transistor and the cathode of the first diode, and the other end of the capacitor under test is electrically connected to the emitter of the second insulated gate bipolar transistor. One end of the third resistor is electrically connected to one end of the capacitor under test, and the other end of the third resistor is electrically connected to the other end of the capacitor under test. One end of the sixth insulating block is connected to the collector of the first insulated gate bipolar transistor, and the other end of the sixth insulating block is connected to the second port; the seventh insulating block is connected in parallel with the sixth insulating block; one end of the eighth insulating block is electrically connected to the other end of the sixth insulating block, and the other end of the eighth insulating block is electrically connected to the emitter of the second insulated gate bipolar transistor; the second metal block is connected in parallel with the eighth insulating block.
[0009] In some embodiments, the circuit further includes: The first power module is connected to the energy storage capacitor module and is used to charge the energy storage capacitor module. A second power module is connected to the test module and is used to charge the test module.
[0010] In some embodiments, the first power module includes a first DC power supply and a first switch, one end of the first switch being electrically connected to the positive terminal of the first DC power supply, the other end of the first switch being electrically connected to one end of the energy storage capacitor module, and the other end of the energy storage capacitor module being electrically connected to the negative terminal of the first DC power supply.
[0011] In some embodiments, the second power module includes a second DC power supply and a second switch, one end of the second switch being electrically connected to the positive terminal of the second DC power supply, the other end of the second switch being electrically connected to one end of the capacitor under test, and the negative terminal of the second DC power supply being electrically connected to the other end of the capacitor under test.
[0012] In some embodiments, the energy storage capacitor module includes a first capacitor and a second capacitor, wherein the first capacitor and the second capacitor are electrically connected in series or in parallel.
[0013] In some embodiments, when the first capacitor and the second capacitor are electrically connected in series, the energy storage capacitor module further includes a first resistor and a second resistor, wherein the first resistor is connected in parallel with the first capacitor and the second resistor is connected in parallel with the second capacitor, and the first resistor and the second resistor are used to limit overcurrent in the circuit.
[0014] In some embodiments, the trigger freewheeling module includes a first thyristor and an inductor, the anode of the first thyristor being electrically connected to one end of the energy storage capacitor module, the cathode of the first thyristor being electrically connected to one end of the inductor, and the other end of the inductor being electrically connected to the first port.
[0015] In some embodiments, the trigger freewheeling module further includes a second thyristor, the anode of which is electrically connected to the cathode of the first thyristor, and the cathode of which is electrically connected to the second port. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of a flexible DC converter valve explosion-proof test circuit according to an embodiment of this application; Figure 2 This is a schematic diagram of a structure in which the IGBT has long-term current-carrying capability in the explosion-proof test of the converter valve submodule provided in this application embodiment; Figure 3 This is a schematic diagram of a structure in which the IGBT in the explosion-proof test of the converter valve submodule provided in this application does not have long-term current carrying capacity; Figure 4 This is a test topology diagram for the explosion-proof test of the converter valve submodule in related technologies; Figure 5 This is a schematic diagram of a circuit structure for an explosion-proof test circuit for a flexible DC converter valve (IGBT with long-term current carrying capacity) provided in an embodiment of this application. Figure 6 This is a schematic diagram of a circuit structure for an explosion-proof test circuit for a flexible DC converter valve (IGBT does not have long-term current carrying capacity) provided in an embodiment of this application.
[0017] Reference numerals: Energy storage capacitor module 100, trigger freewheeling module 200, subject module 300, high-speed recording module 400. Detailed Implementation
[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.
[0019] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.
[0020] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.
[0021] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0022] Flexible DC transmission (VSC-HVDC) is a DC transmission technology that uses fully controlled devices such as insulated-gate bipolar transistors (IGBTs) as core power devices. Compared with conventional DC transmission (LCC-HVDC), it has advantages in reactive power compensation, no need for a supporting power supply, no commutation failure, and flexible power control. In addition to being suitable for conventional DC applications, this technology has significant advantages in scenarios such as offshore wind power transmission, power supply to large cities, DC grid construction, power supply to offshore platforms / islands / processing industries, and new energy transmission from desert and Gobi areas.
[0023] With the continuous improvement of voltage levels and transmission capacity in flexible DC transmission systems, the capacitance and voltage levels of converter valve submodules have also increased. This leads to a significant increase in the short-circuit discharge energy of the submodules under extreme fault conditions, further increasing the short-circuit current they withstand and thus enhancing their destructive potential. To improve the reliability of the converter valves, the converter valve submodules must maintain long-term current-carrying capacity even under the most extreme operating conditions without affecting the normal operation of other submodules. Therefore, explosion-proof tests (bypass failure tests) are typically conducted to simulate scenarios where the bypass switch fails to operate, the capacitor voltage rises abnormally, and devices such as diodes, IGBTs, and transition thyristors (if present) break down, causing direct discharge of the capacitor. This verifies that the submodule does not affect or damage other submodules or equipment under these extreme conditions.
[0024] like Figure 1 As shown, Figure 1This is a circuit diagram illustrating the long-term current-carrying capability of the IGBT in the explosion-proof test of the converter valve submodule provided in this application embodiment. The circuit uses IGBT T1 and IGBT T2 as the main current-carrying devices, with diodes D1 and D2 connected in anti-parallel to assist freewheeling, respectively. When the bypass fails to operate, the driving active clamping circuit breaks down the lower conducting IGBT. After the IGBT fails, it can maintain long-term current-carrying capability without the need for additional replacement components. Therefore, the circuit directly relies on the current-carrying capability of the IGBT to achieve fault current conduction. During the charging phase, diode D1 charges capacitor C, gradually increasing the capacitor voltage. When the voltage reaches the clamping action voltage of the IGBT driver board (where the IGBT has long-term current-carrying capability), diode D1 undergoes reverse recovery failure, and capacitor C discharges through a short circuit via diodes D1 and IGBT T2, simulating the fault scenario.
[0025] like Figure 2 As shown, Figure 2 This is a circuit diagram illustrating the circuit structure of the converter valve submodule provided in this application during the explosion-proof test, where the IGBT lacks long-term current-carrying capability. Since the IGBT lacks long-term current-carrying capability after failure, a thyristor (SCR) is introduced as a substitute current-carrying device to handle the long-term current-carrying function after breakdown and conduction. During charging, capacitor C is charged through diode D1, causing the capacitor voltage to rise. When the voltage rises to the thyristor breakdown voltage (where the IGBT lacks long-term current-carrying capability), diode D1 reverses and fails, and capacitor C short-circuits and discharges through diode D1 and the SCR, completing the simulation of extreme operating conditions.
[0026] In related technologies, explosion-proof tests of converter valve submodules are mostly conducted at the valve section level, and their test topology is as follows: Figure 3As shown, the following significant drawbacks exist: (a) Numerous required modules (paired testing): Valve section testing typically employs a "paired" method to construct the power circuit. This means that in addition to the DUT, a large number of additional sub-modules are needed as "accompanying modules" to form a complete test circuit. This significantly increases testing costs (high unit price of sub-modules) and resource investment. (b) Large workload for valve section platform construction: Testing on the valve section requires the construction of a complete valve section platform, including mechanical support structures, cooling systems (water pipes), complex electrical connections (busbars, optical fibers), controller (VBC) interfaces, measurement systems, etc. This process is extensive, time-consuming, and costly. (c) Complex, time-consuming, and uncertain software debugging: Valve section testing relies on valve section-level control and protection software (such as VBC software) to coordinate the operation of all sub-modules and simulate fault conditions. This requires complex software configuration, debugging, and joint debugging, consuming a large amount of manpower and time. More importantly, it is difficult to achieve diode reverse recovery damage conditions through software control, therefore the test results (whether explosion protection can be effectively triggered) are highly uncertain and have a low success rate. (d) The test focus is prone to shift: The complexity of the valve section level may introduce additional variables, making it difficult to accurately control the fault energy distribution, protection action sequence, etc., which is not conducive to directly and purely testing the explosion-proof performance of the sub-module under test itself.
[0027] Based on this, this application provides an explosion-proof test circuit for a flexible DC converter valve, which can effectively improve the accuracy of testing the protective performance of the flexible DC converter valve, thereby improving the reliability of flexible DC power transmission.
[0028] See Figure 4This is a schematic diagram of the structure of a flexible DC converter valve explosion-proof test circuit provided in an embodiment of this application. The flexible DC converter valve explosion-proof test circuit includes an energy storage capacitor module 100, a trigger freewheeling module 200, a test module 300, and a high-speed recording module 400. The system includes an energy storage capacitor module 100 for storing a large amount of energy required for explosion-proof testing; a trigger freewheeling module 200 electrically connected to the energy storage capacitor module 100, which controls the energy from the energy storage capacitor module 100 to be injected into the test module 300 in a directional manner, ensuring that the test module 300 is triggered to short-circuit discharge; a test module 300 electrically connected to the trigger freewheeling module 200, which includes a test capacitor and a bridge arm composed of an insulated gate bipolar transistor and a diode, forming a current path for explosion-proof testing; and a high-speed recording module 400 electrically connected to both the energy storage capacitor module 100 and the test module 300, which synchronously records the voltage of the energy storage capacitor module 100, the voltage of the test capacitor, the port voltage of the test module 300, the charging current injected into the test module 300, the waveform of the explosion-proof current of the test module 300, and key time points, etc. The recorded content can be adjusted according to actual needs, and no specific limitation is made here. Among them, the key time point is the triggering time of the continuous flow module 200.
[0029] Compared with existing technologies, the explosion-proof test circuit for a flexible DC converter valve provided in this application has the following advantages: It stores a large capacity of energy through an energy storage capacitor module, providing a sufficient energy foundation for simulating extreme fault scenarios; it precisely controls the directional injection of energy using a trigger freewheeling module, ensuring reliable triggering of short-circuit discharge scenarios in the tested module and improving test accuracy; the bridge arm structure of the tested module includes the tested capacitor, IGBT, and diode, forming a complete current path, which can be adapted to devices with different characteristics (whether the IGBT has long-term current carrying capacity); combined with the high-speed recording module's synchronous recording of multi-dimensional electrical parameters (voltage, current waveforms) and key time points, it can comprehensively capture data from the test process, providing accurate basis for analyzing the explosion-proof performance of the tested module. In summary, this circuit abandons the valve platform and drag-and-drop mode in existing technologies, directly injecting fault energy into the tested module through an independently controllable large-capacity energy source, accurately simulating extreme fault conditions (bypass failure leading to capacitor overvoltage discharge), effectively improving the accuracy of testing the protection performance of flexible DC converter valves, thereby improving the reliability of flexible DC transmission.
[0030] Please see Figure 5 The test module 300 has a first port AC1 and a second port AC2. The first port AC1 is electrically connected to one end of the trigger continuous current module 200, and the second port AC2 is electrically connected to the other end of the trigger continuous current module 200.
[0031] When the insulated gate bipolar transistor of the test module 300 has long-term current-carrying capability, the test module 300 includes a first insulated gate bipolar transistor T1, a first diode D1, a second insulated gate bipolar transistor T2, a second diode D2, a test capacitor C3, a third resistor R3, a first insulating block IB1, a second insulating block IB2, a third insulating block IB3, and a first metal block MB1; the collector of the first insulated gate bipolar transistor T1 is electrically connected to one end of the test capacitor C3, the emitter of the first insulated gate bipolar transistor T1 is electrically connected to the anode of the first diode D1, and the cathode of the first diode D1 is connected in reverse parallel with the collector of the first insulated gate bipolar transistor T1; The collector of the second insulated gate bipolar transistor T2 is electrically connected to the emitter of the first insulated gate bipolar transistor T1. The emitter of the second insulated gate bipolar transistor T2 is electrically connected to the anode of the second diode D2. The cathode of the second diode D2 is connected in reverse parallel with the collector of the second insulated gate bipolar transistor T2. One end of the capacitor under test C3 is electrically connected to the junction of the collector of the first insulated gate bipolar transistor T1 and the cathode of the first diode D1. The other end of the capacitor under test C3 is electrically connected to the junction of the emitter of the second insulated gate bipolar transistor T2 and the anode of the second diode D2. One end of the third resistor R3 is electrically connected to one end of the capacitor under test C3, and the other end of the third resistor R3 is electrically connected to the other end of the capacitor under test C3. One end of the first insulating block IB1 is connected to the collector of the first insulated gate bipolar transistor T1, and the other end of the first insulating block IB1 is connected to the second port AC2; the second insulating block IB2 is connected in parallel with the first insulating block IB1; one end of the first metal block MB1 is electrically connected to the other end of the first insulating block IB1, and the other end of the first metal block MB1 is electrically connected to the emitter of the second insulated gate bipolar transistor T2; the third insulating block IB3 is connected in parallel with the first metal block MB1.
[0032] This application conducts explosion-proof tests using a single module. By constructing a charging circuit to inject high energy into the module under test, it accurately simulates actual fault scenarios, significantly simplifies the testing process, improves testing efficiency, and ensures reliable evaluation of explosion-proof performance.
[0033] A first power supply module, connected to the energy storage capacitor module 100, is used to charge the first capacitor C1 and the second capacitor C2 in the energy storage capacitor module 100. Specifically, the first power supply module includes a first DC power supply DC1 and a first switch K1. One end of the first switch K1 is electrically connected to the positive terminal of the first DC power supply DC1, and the other end of the first switch K1 is electrically connected to one end of the energy storage capacitor module 100. The other end of the energy storage capacitor module 100 is electrically connected to the negative terminal of the first DC power supply DC1. The first switch K1 is used to control the first DC power supply DC1 to charge the energy storage capacitor module 100.
[0034] A second power supply module, connected to the test module 300, is used to charge the test capacitor C3 in the test module 300. Specifically, the second power supply module includes a second DC power supply DC2 and a second switch K2. One end of the second switch K2 is electrically connected to the positive terminal of the second DC power supply DC2, and the other end of the second switch K2 is electrically connected to one end of the test capacitor C3. The negative terminal of the second DC power supply DC2 is electrically connected to the other end of the test capacitor C3. The second switch K2 is used to control the second DC power supply DC2 to charge the test capacitor C3.
[0035] The energy storage capacitor module 100 includes a first capacitor C1 and a second capacitor C2, which are electrically connected in series or in parallel. Specifically, when the first capacitor C1 and the second capacitor C2 are connected in series, the energy storage capacitor module 100 also includes a first resistor R1 and a second resistor R2. The first resistor R1 is connected in parallel with the first capacitor C1, and the second resistor R2 is connected in parallel with the second capacitor C2. The first resistor R1 and the second resistor R2 are used to limit overcurrent in the circuit. In this case, the energy storage capacitor module 100 needs to withstand a fault current of up to 5000A.
[0036] The trigger freewheeling module 200 includes a first thyristor SCR1 and an inductor L. The anode of the first thyristor SCR1 is electrically connected to one end of the energy storage capacitor module 100, and the cathode of the first thyristor SCR1 is electrically connected to one end of the inductor L. The other end of the inductor L is electrically connected to the first port AC1. The first thyristor SCR1 is a trigger thyristor, through which the first capacitor C1 and the second capacitor C2 charge the capacitor under test C3. The inductance value of the inductor L can be set according to actual test requirements and is not specifically limited here.
[0037] In some embodiments, the trigger freewheeling module 200 may further include a second thyristor SCR2, the anode of which is electrically connected to the cathode of the first thyristor SCR1, and the cathode of which is electrically connected to the second port AC2. The second thyristor SCR2 is used to turn on the freewheeling current in the second insulated-gate bipolar transistor T2.
[0038] In some other embodiments, the trigger freewheeling module 200 may not include the second thyristor SCR2. In the absence of the second thyristor SCR2 for freewheeling in the inductor L, the energy stored in the inductor L can charge the capacitor under test C3 through the broken-down second insulated gate bipolar transistor T2 and the third thyristor SCR3, making the voltage of the capacitor under test C3 negative. This eliminates the need for the second thyristor SCR2 in the circuit setup of the test circuit.
[0039] In some embodiments, the high-speed recording module 400 includes a first voltage sensor V1, a second voltage sensor V2, a third voltage sensor V3, a first current sensor A1, and a second current sensor A2. The first voltage sensor V1 is used to record the voltage of the energy storage capacitor module 100; the second voltage sensor V2 is used to record the port voltage of the module under test 300; the third voltage sensor V3 is used to record the voltage of the capacitor under test C3; the first current sensor A1 is used to record the charging current injected into the module under test 300; and the second current sensor A2 is used to record the waveform and key time points of the explosion-proof current (i.e., the first diode D1) of the module under test 300. The key time points include the triggering time of the first thyristor SCR1 in the freewheeling module 200. Figure 5 Some monitoring points for voltage and current sensors are listed. In practice, the number of monitoring points for voltage / current sensors can be increased or decreased depending on the experimental conditions.
[0040] Please see Figure 6 The test module 300 has a first port AC1 and a second port AC2. The first port AC1 is electrically connected to one end of the trigger freewheeling module 200, and the second port AC2 is electrically connected to the other end of the trigger freewheeling module 200. When the insulated gate bipolar transistor of the test module 300 does not have long-term current carrying capability, the test module 300 includes a first insulated gate bipolar transistor T1, a first diode D1, a third thyristor SCR3, a second insulated gate bipolar transistor T2, a fifth insulating block IB5, a test capacitor C3, a third resistor R3, a sixth insulating block IB6, a seventh insulating block IB7, an eighth insulating block IB8, and a second metal block MB2. The first main electrode of the third thyristor SCR3 is electrically connected to the second port AC2, and the second main electrode of the third thyristor SCR3 is electrically connected to the first port AC1. The collector of the first insulated gate bipolar transistor T1 is electrically connected to one end of the capacitor under test C3, the emitter of the first insulated gate bipolar transistor T1 is electrically connected to the anode of the first diode D1, and the cathode of the first diode D1 is connected in reverse parallel with the collector of the first insulated gate bipolar transistor T1. The collector of the second insulated gate bipolar transistor T2 is electrically connected to the emitter of the first insulated gate bipolar transistor T1. The emitter of the second insulated gate bipolar transistor T2 is connected to one end of the fifth insulating block IB5, and the other end of the fifth insulating block IB5 is connected to the collector of the second insulated gate bipolar transistor T2. One end of the capacitor under test C3 is electrically connected to the connection node between the collector of the first insulated gate bipolar transistor T1 and the cathode of the first diode D1, and the other end of the capacitor under test C3 is electrically connected to the emitter of the second insulated gate bipolar transistor T2. One end of the third resistor R3 is electrically connected to one end of the capacitor under test C3, and the other end of the third resistor R3 is electrically connected to the other end of the capacitor under test C3. One end of the sixth insulating block IB6 is connected to the collector of the first insulated gate bipolar transistor T1, and the other end of the sixth insulating block IB6 is connected to the second port AC2; the seventh insulating block IB7 is connected in parallel with the sixth insulating block IB6; one end of the eighth insulating block IB8 is electrically connected to the other end of the sixth insulating block IB6, and the other end of the eighth insulating block IB8 is electrically connected to the emitter of the second insulated gate bipolar transistor T2; the second metal block MB2 is connected in parallel with the eighth insulating block IB8.
[0041] Please see Figure 5 , Figure 6 This explosion-proof test circuit charges the tested capacitor C3 through the first capacitor C1 and the second capacitor C2 via the first diode D1, causing the voltage of the tested capacitor C3 to gradually increase (e.g., Figure 5 , Figure 6 (As shown by the red dashed line in the middle). When the voltage of the tested capacitor C3 reaches the clamping voltage of the IGBT (applicable to... Figure 5 (In scenarios where the IGBT has long-term current carrying capacity) or the breakdown voltage of the thyristor (applicable to) Figure 6 In scenarios where the IGBT lacks long-term current carrying capacity, the first diode D1 experiences reverse recovery failure, and the tested capacitor C3 forms a short-circuit discharge circuit through either the first diode D1 and IGBT T2 or the first diode D1 and the third thyristor SCR3 (e.g., Figure 5 , Figure 6 (As shown by the blue dashed line).
[0042] To ensure precise failure of the first diode D1 during reverse recovery, this application charges the first diode D1 with a large current, causing it to fail beyond its safe operating area during the reverse recovery phase. Simultaneously, a circuit model is built using simulation software, and the initial voltage values of the first capacitor C1, the second capacitor C2, and the capacitor under test C3 are adjusted to ensure that the IGBT T2 conducts or the third thyristor SCR3 breaks down under the target high current and voltage conditions, thereby triggering the failure of diode D1 during reverse recovery. The first capacitor C1 and the second capacitor C2 support both series and parallel connections, which can be flexibly switched according to actual testing requirements.
[0043] In one specific embodiment, firstly, the test module 300 is prepared. The converter valve submodule is structurally modified, changing its full-bridge topology to a half-bridge topology to verify the structural protection of one of the discharge circuits and adapt it to the test requirements. For example...Figure 5 In this approach, an insulating block is used to replace one of the upper IGBT devices in the submodule with long-term current-carrying capability, and an insulating block is connected in parallel with it. Then, a metal block is used to replace one of the lower IGBT devices in the same submodule, and an insulating block is connected in parallel with it. This constructs an equivalent test circuit, saving on test components. Figure 6 Similarly.
[0044] Furthermore, a high-capacity, high-power DC power supply or energy storage device, independent of the converter valve control system, is used as a fault energy source to charge the capacitor bank (first capacitor C1 and second capacitor C2). This capacitor bank (first capacitor C1 and second capacitor C2) can be combined in series or parallel according to test requirements (such as simulating the target fault energy level I²t), and its capacity and voltage level can be designed and selected as needed.
[0045] Furthermore, a fault injection circuit is set up. In the main circuit between the energy source and the tested module 300, a controllable high-power switching device (such as a high-capacity thyristor SCR or IGBT) and an inductor are connected in series. The switching device is used to control the on / off state of the fault energy injection circuit.
[0046] Furthermore, the test module 300 is equipped with the necessary low-voltage auxiliary power supply (if necessary to power its internal controller) and switching device trigger circuit; a voltage sensor (to monitor the voltage of the test capacitor and the voltage of the test module port) and a current sensor (to measure the charging current injected into the test module and the explosion-proof discharge current) are deployed, and a high-speed data logger is connected to collect the waveforms of the above key electrical parameters; the test process does not require connection or debugging of complex valve section level control and protection software (VBC software).
[0047] Furthermore, considering the safety protection requirements for explosion venting, the test module 300 is housed within a protective enclosure. The test does not require the construction of a complete valve section mechanical structure, integrated cooling system, or multi-module electrical interconnection platform, nor does it require the configuration of a supporting sub-module.
[0048] A circuit model is built using simulation software. The stray parameters of the circuit are first calibrated in a low current and low voltage mode. Then, the initial voltage values of the first capacitor C1, the second capacitor C2, and the capacitor under test C3 are adjusted to ensure that under the target high current and voltage conditions, the IGBT T2 is turned on or the third thyristor SCR3 is over-voltage broken down, thereby triggering the first diode D1 to be damaged during the reverse recovery process.
[0049] Finally, the test steps include: the first DC power supply DC1 precharges the first capacitor C1 and the second capacitor C2 to a preset value, and the second DC power supply DC2 charges the tested capacitor C3 to a preset value; the first switch K1 and the second switch K2 are disconnected respectively; the first thyristor SCR1 and the second thyristor SCR2 are triggered simultaneously, the first capacitor C1 and the second capacitor C2 charge the tested capacitor C3 of the tested module 300 through the first thyristor SCR1, and the second thyristor SCR2 provides a freewheeling path for the subsequent conduction of IGBT T2; when the charging voltage of the tested module 300 reaches the set threshold, the IGBT is triggered by an active clamping action. When T2 is turned on or the third thyristor SCR3 is overvoltage-broken, a direct discharge circuit is formed between the first diode D1 and the second insulated gate bipolar transistor T2, or between the first diode D1 and the third thyristor SCR3, triggering the explosion-proof condition of the test module 300. The high-speed recording module 400 synchronously collects waveform data and key time points (such as the switch triggering time) of the voltage of the test capacitor C3, the port voltage of the test module 300, the charging current injected into the test module 300, and the explosion-proof discharge current (first diode D1). After the explosion-proof test is completed and the test capacitor C3 is completely discharged, the test module 300 is fully inspected. The observation content includes: whether there are any splashes from the test module 300, the degree of device damage, the displacement of the water-cooled substrate, and whether there are any abnormalities such as water leakage.
[0050] This application directly tests a single Module Under Test (DUT) without requiring any auxiliary modules, significantly reducing the use of expensive sub-modules and substantially lowering testing costs. Furthermore, this application utilizes an independently controllable, large-capacity energy storage device (capacitor bank) to directly charge and inject energy into the DUT. The test circuit only includes "energy source - controllable switch - inductor - DUT," eliminating the need to build a complete valve platform with mechanical structures, cooling systems, complex electrical connections, and VBC interfaces. It also omits the complex interconnections between auxiliary modules and the valve platform, greatly simplifying test preparation and shortening the test cycle. Moreover, this application achieves this through a simple and independent control unit. By bypassing the complex valve section-level software control system, this fault-triggered approach avoids dependence on valve section control software (VBC), solving the problems of time-consuming software debugging and integration, and difficulty in accurately controlling parameters at fault moments in traditional solutions. Furthermore, this application eliminates the interference of the complexity of the valve section system, focusing the test on the performance of the module under test itself. It can purely and directly test its explosion-proof design, protection capability, and structural strength, and the test results can truly reflect the actual explosion-proof performance of the module under test. This application has a short test preparation time, low resource investment, and low cost per test, which improves test efficiency, reduces R&D testing costs, and effectively shortens the product iteration and verification cycle.
[0051] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.
[0052] The above description is the preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications are also considered to be within the scope of protection of this application.
Claims
1. A flexible DC converter valve explosion proof test circuit, characterized by, The application relates to a flexible DC converter valve explosion-proof test circuit. The application comprises the following parts: a storage capacitor module for storing large-capacity energy required for explosion-proof test; a trigger and freewheeling module electrically connected with the storage capacitor module, which is used for controlling directional injection of energy of the storage capacitor module to a test module, and ensuring triggering of short-circuit discharge of the test module; a test module electrically connected with the trigger and freewheeling module, which comprises a test capacitor and a bridge arm composed of an insulated gate bipolar transistor and a diode, and the bridge arm forms a current path for explosion-proof test; a high-speed recording module electrically connected with the storage capacitor module and the test module respectively, which is used for synchronously recording waveforms and key time points of voltage of the storage capacitor module, voltage of the test capacitor, port voltage of the test module, charging current injected into the test module and explosion-proof current of the test module, and the key time points include a triggering time of the trigger and freewheeling module.
2. The flexible DC converter valve explosion-proof test circuit according to claim 1, wherein the test module has a first port and a second port, the first port is electrically connected with one end of the trigger and freewheeling module, and the second port is electrically connected with the other end of the trigger and freewheeling module; when the insulated gate bipolar transistor of the test module has long-term current-carrying capacity, the test module comprises a first insulated gate bipolar transistor, a first diode, a second insulated gate bipolar transistor, a second diode, a test capacitor, a third resistor, a first insulating block, a second insulating block, a third insulating block and a first metal block; a collector of the first insulated gate bipolar transistor is electrically connected with one end of the test capacitor, an emitter of the first insulated gate bipolar transistor is electrically connected with an anode of the first diode, and a cathode of the first diode is reversely connected in parallel with the collector of the first insulated gate bipolar transistor; a collector of the second insulated gate bipolar transistor is electrically connected with the emitter of the first insulated gate bipolar transistor, an emitter of the second insulated gate bipolar transistor is electrically connected with an anode of the second diode, and a cathode of the second diode is reversely connected in parallel with the collector of the second insulated gate bipolar transistor; one end of the test capacitor is electrically connected with a connection node of the collector of the first insulated gate bipolar transistor and the cathode of the first diode, the other end of the test capacitor is electrically connected with a connection node of the emitter of the second insulated gate bipolar transistor and the anode of the second diode, one end of the third resistor is electrically connected with one end of the test capacitor, and the other end of the third resistor is electrically connected with the other end of the test capacitor; one end of the first insulating block is connected with the collector of the first insulated gate bipolar transistor, the other end of the first insulating block is connected with the second port, the second insulating block is connected in parallel with the first insulating block, one end of the first metal block is electrically connected with the other end of the first insulating block, the other end of the first metal block is electrically connected with the emitter of the second insulated gate bipolar transistor, and the third insulating block is connected in parallel with the first metal block.
3. The flexible HVDC valve explosion-proof test circuit of claim 1, wherein, the test module has a first port and a second port, the first port is electrically connected to one end of the trigger freewheeling module, and the second port is electrically connected to the other end of the trigger freewheeling module; when the test module does not have long-term current-carrying capability, the test module includes a first IGBT, a first diode, a third thyristor, a second IGBT, a fifth insulating block, a test capacitor, a third resistor, a sixth insulating block, a seventh insulating block, an eighth insulating block, and a second metal block; the first main electrode of the third thyristor is electrically connected to the second port, and the second main electrode of the third thyristor is electrically connected to the first port; the collector of the first IGBT is electrically connected to one end of the test capacitor, the emitter of the first IGBT is electrically connected to the anode of the first diode, and the cathode of the first diode is reversely connected in parallel with the collector of the first IGBT; the collector of the second IGBT is electrically connected to the emitter of the first IGBT, one end of the fifth insulating block is connected to the emitter of the second IGBT, and the other end of the fifth insulating block is connected to the collector of the second IGBT; one end of the test capacitor is electrically connected to the connection node of the collector of the first IGBT and the cathode of the first diode, the other end of the test capacitor is electrically connected to the emitter of the second IGBT, one end of the third resistor is electrically connected to one end of the test capacitor, and the other end of the third resistor is electrically connected to the other end of the test capacitor; one end of the sixth insulating block is connected to the collector of the first IGBT, the other end of the sixth insulating block is connected to the second port, the seventh insulating block is connected in parallel with the sixth insulating block, one end of the eighth insulating block is electrically connected to the other end of the sixth insulating block, the other end of the eighth insulating block is electrically connected to the emitter of the second IGBT, and the second metal block is connected in parallel with the eighth insulating block.
4. The flexible DC converter valve explosion proof test circuit of claim 1, wherein, The circuit further comprises: a first power supply module connected to the energy storage capacitor module for charging the energy storage capacitor module; a second power supply module connected to the test module, the second power supply module being used for charging the test module.
5. The flexible DC converter valve explosion proof test circuit of claim 4, wherein, The first power supply module includes a first DC power supply and a first switch, one end of the first switch is electrically connected to the positive electrode of the first DC power supply, the other end of the first switch is electrically connected to one end of the energy storage capacitor module, and the other end of the energy storage capacitor module is electrically connected to the negative electrode of the first DC power supply.
6. The flexible DC converter valve explosion proof test circuit of claim 4, wherein, The second power supply module includes a second DC power supply and a second switch, one end of the second switch is electrically connected to the positive electrode of the second DC power supply, the other end of the second switch is electrically connected to one end of the test capacitor, and the negative electrode of the second DC power supply is electrically connected to the other end of the test capacitor.
7. The flexible DC converter valve explosion proof test circuit of claim 1, wherein, The energy storage capacitor module comprises a first capacitor and a second capacitor, and the first capacitor and the second capacitor are electrically connected in series or in parallel.
8. The flexible DC converter valve explosion proof test circuit of claim 7, wherein, When the first capacitor and the second capacitor are electrically connected in series, the energy storage capacitor module further comprises a first resistor and a second resistor, the first resistor is connected in parallel with the first capacitor, the second resistor is connected in parallel with the second capacitor, and the first resistor and the second resistor are used to limit the circuit overcurrent.
9. The flexible DC converter valve explosion proof test circuit of claim 2 or 3, wherein, The trigger freewheeling module comprises a first thyristor and an inductor, an anode of the first thyristor is electrically connected with one end of the energy storage capacitor module, a cathode of the first thyristor is electrically connected with one end of the inductor, and the other end of the inductor is electrically connected with the first port.
10. The flexible DC converter valve explosion proof test circuit of claim 9, wherein, The trigger freewheeling module further comprises a second thyristor, an anode of the second thyristor is electrically connected with the cathode of the first thyristor, and a cathode of the second thyristor is electrically connected with the second port.