A high voltage electronic switching device and control method

Abstract

The application discloses a high-voltage electronic switch device and a control method, relates to the technical field of power electronics and high-voltage testing, and the device comprises a single-chip microcomputer and a plurality of IGBT switch modules which are connected in series, each IGBT switch module comprises a trigger isolation optocoupler, a trigger circuit unit, an IGBT tube, a voltage detection circuit unit and a detection isolation optocoupler; the trigger isolation optocouplers are connected with the single-chip microcomputer and the trigger circuit unit respectively, the trigger circuit unit is connected with the gate of the IGBT tube, and the voltage detection circuit unit is connected in parallel across the IGBT tube and is fed back to the single-chip microcomputer through the detection isolation optocoupler. The method comprises the following steps: performing multiple no-load closing tests to obtain actual closing time difference data, calculating the average fixed time delay of each module and performing discreteness evaluation, determining the channel compensation amount of each module after the evaluation is qualified, and performing a closing operation with load. The device realizes the microsecond-level synchronous conduction of all levels of IGBT tubes, eliminates the dynamic voltage unevenness caused by the discreteness of device parameters and driving delay, and improves the reliability of the device.

Description

Technical Field

[0001] This invention relates to the field of power electronics and high voltage testing technology, and in particular to a high voltage electronic switching device and control method. Background Technology

[0002] In high-voltage equipment impulse withstand voltage tests, it is typically necessary to generate high-voltage pulses or perform rapid and reliable switching control on high-voltage circuits. With the continuous increase in power system voltage levels, the voltage levels that test equipment and high-voltage switchgear need to withstand have risen from several kV to tens of kV or even higher. While traditional mechanical high-voltage switches can withstand higher voltages, their slow operating speed, mechanical contact bounce, and tendency to generate arcs during opening and closing, leading to contact erosion and wear, make them unsuitable for meeting the requirements of modern high-voltage testing for speed, repeatability, and low maintenance costs. Meanwhile, power semiconductor devices (such as IGBTs) are gradually becoming alternatives in the high-voltage switchgear field due to their advantages such as fast switching speed and no mechanical contacts. However, the withstand voltage of a single IGBT device is usually limited (e.g., the common 4500V or 6500V level). In high-voltage scenarios of 20kV and above, multiple low-voltage IGBTs need to be used in series to share the system voltage.

[0003] In a multi-stage IGBT series topology, although theoretically each stage of the device shares the total voltage equally, in practical engineering applications, due to the inherent dispersion of materials, structure, and process parameters in each IGBT during manufacturing, and the inevitable slight differences in component parameters in the corresponding drive circuits for each stage, the arrival time of the same trigger signal at the gates of each IGBT and the turn-on delay time of each IGBT are not completely consistent. This inconsistency is particularly fatal in series voltage division scenarios: the first IGBT to turn on must bear all or most of the voltage of the remaining unconverted devices at the moment of turn-on, while the last IGBT to turn on is forced to turn on under high voltage, and both are extremely susceptible to breakdown and damage due to instantaneous overvoltage. The currently used passive voltage equalization measures can only alleviate voltage distribution under steady-state conditions and are difficult to effectively deal with dynamic voltage imbalance during switching transients. The synchronization of the operation of series IGBTs has become the core bottleneck restricting their high-voltage engineering applications. Summary of the Invention

[0004] This invention provides a high-voltage electronic switching device and control method, which solves the technical problem of asynchronous switching action caused by parameter dispersion and drive delay differences in multi-stage series IGBTs, resulting in dynamic voltage unevenness.

[0005] The first aspect of this invention provides a high-voltage electronic switching device, comprising a microcontroller and a multi-stage series IGBT switching module formed by connecting multiple IGBT switching modules in series.

[0006] Each of the IGBT switching modules includes a trigger isolation optocoupler, a trigger circuit unit, an IGBT transistor, a voltage detection circuit unit, and a detection isolation optocoupler;

[0007] One end of the trigger isolation optocoupler is connected to the microcontroller;

[0008] The other end of the trigger isolation optocoupler is connected to one end of the trigger circuit;

[0009] The other end of the trigger circuit is connected to the gate of the IGBT transistor;

[0010] The input terminal of the voltage detection circuit unit is connected in parallel with the IGBT transistor;

[0011] The output terminal of the voltage detection circuit unit is connected to one end of the detection isolation optocoupler;

[0012] The other end of the detection isolation optocoupler is connected to the microcontroller.

[0013] Optionally, each of the IGBT switching modules further includes an isolated independent power supply;

[0014] The trigger isolation optocoupler, the trigger circuit unit, the IGBT transistor, the voltage detection circuit unit, and the detection isolation optocoupler are all connected to the isolated independent power supply.

[0015] Optionally, the trigger isolation optocoupler includes a trigger isolation transmitting optocoupler and a trigger isolation receiving optocoupler;

[0016] The input terminal of the trigger isolation emitter optocoupler is connected to the microcontroller;

[0017] The output terminal of the trigger-isolated transmitting optocoupler is connected to the input terminal of the trigger-isolated receiving optocoupler;

[0018] The output terminal of the trigger isolation receiver optocoupler is connected to one end of the trigger circuit.

[0019] Optionally, the detection isolation optical coupler includes a detection isolation transmitting optical coupler and a detection isolation receiving optical coupler;

[0020] The output terminal of the voltage detection circuit unit is connected to the input terminal of the detection isolation emission optocoupler;

[0021] The output terminal of the detection isolation transmitting optocoupler is connected to the input terminal of the detection isolation receiving optocoupler;

[0022] The output of the detection isolation receiving optocoupler is connected to the microcontroller.

[0023] Optionally, each of the IGBT switching modules further includes a surge arrester;

[0024] The surge arrester is connected in parallel with the IGBT tube.

[0025] A second aspect of the present invention provides a control method for the aforementioned high-voltage electronic switching device, comprising:

[0026] Control each IGBT switching module to perform multiple no-load closing tests to obtain the corresponding actual closing time difference data;

[0027] The average fixed delay corresponding to each IGBT switching module is calculated using the actual closing time difference data;

[0028] Discreteness assessment is performed on the actual closing time difference data described above;

[0029] When the discreteness evaluation result is qualified, the channel compensation amount corresponding to each IGBT switching module is determined by the average fixed time delay.

[0030] Based on the compensation amount of each channel, perform a load-bearing closing operation on each IGBT switching module.

[0031] Optionally, the multiple no-load closing tests specifically include:

[0032] One of the multiple IGBT switching modules is pre-set as the reference IGBT tube;

[0033] Under no-load conditions, trigger pulse electrical signals are simultaneously sent to multiple IGBT switching modules;

[0034] The trigger isolation optocoupler controls the trigger pulse electrical signal to be converted into a trigger pulse optical signal, which then passes through the isolation strip and is restored to a trigger pulse electrical signal and sent to the trigger circuit unit.

[0035] The control trigger circuit unit amplifies the power of the restored trigger pulse electrical signal to drive the IGBT to conduct.

[0036] The control voltage detection circuit unit captures the falling edge jump signal of the IGBT in real time and sends it to the detection isolation optocoupler;

[0037] The control detection isolation optocoupler converts the falling edge jump signal into an optical signal that passes through the isolation strip, and then restores it to a falling edge jump signal;

[0038] Edge capture is performed on the restored falling edge jump signal to record the actual arrival time of the falling edge of each IGBT transistor.

[0039] Using the actual arrival time of the voltage drop edge of the reference stage IGBT in each closing test as the reference time, the actual arrival time of each stage IGBT is subtracted from the reference time to obtain the actual closing time difference under a single no-load closing test.

[0040] By integrating the actual closing time differences under all no-load closing tests, the actual closing time difference data corresponding to each IGBT switch module is obtained.

[0041] Optionally, when the discreteness evaluation result is qualified, determining the channel compensation amount corresponding to each IGBT switching module using the average fixed delay includes:

[0042] When the discreteness evaluation result is qualified, the maximum value is selected from all the average fixed delays as the maximum average fixed delay.

[0043] Subtract each of the average fixed delays from the maximum average fixed delay to obtain the channel compensation amount corresponding to each IGBT switching module;

[0044] The channel compensation amount is the advance trigger time corresponding to each IGBT switching module relative to the maximum average fixed delay.

[0045] Optionally, when the discreteness evaluation result is qualified, determining the channel compensation amount corresponding to each IGBT switching module using the average fixed delay further includes:

[0046] When the discreteness evaluation result is qualified, the theoretical reference trigger time of the reference-level IGBT is obtained;

[0047] Subtract each of the average fixed delays from the theoretical benchmark trigger times to obtain the channel compensation amount corresponding to each IGBT switching module.

[0048] The channel compensation amount is the absolute trigger time value of each IGBT switching module relative to the theoretical reference trigger time.

[0049] Optionally, the discreteness assessment of each of the actual closing time difference data includes:

[0050] Calculate the standard deviation of each of the actual closing time difference data;

[0051] If all the standard deviations are less than the preset acceptable threshold, the dispersion assessment result is deemed acceptable.

[0052] If any of the standard deviations is not less than the preset acceptable threshold, the dispersion assessment result is determined to be unacceptable.

[0053] As can be seen from the above technical solutions, the present invention has the following advantages:

[0054] This invention provides a high-voltage electronic switching device and control method. It employs a microcontroller connected in series with multiple IGBT switching modules to form a multi-stage series structure. Each IGBT switching module includes a trigger isolation optocoupler, a trigger circuit unit, an IGBT transistor, a voltage detection circuit unit, and a detection isolation optocoupler. The trigger isolation optocoupler is connected to both the microcontroller and the trigger circuit unit. The trigger circuit unit is connected to the gate of the IGBT transistor. The input terminal of the voltage detection circuit unit is connected in parallel with the IGBT transistor, and its output terminal is connected to the microcontroller via the detection isolation optocoupler. During operation, the trigger pulse issued by the microcontroller is transmitted to the trigger circuit unit via the trigger isolation optocoupler, which then drives the IGBT transistor to turn on. Simultaneously, the voltage detection circuit unit, connected in parallel across the IGBT transistor, captures the falling edge signal of the voltage at the moment the IGBT transistor turns on in real time and feeds it back to the microcontroller via the detection isolation optocoupler. This constructs an independent closed-loop detection link of "issuing trigger command - real-time feedback of action moment" in each stage of the IGBT switching module. Because each IGBT switching module has an independent and complete trigger isolation transmission channel and a real-time voltage drop edge feedback channel, the microcontroller can accurately obtain the time deviation between the actual conduction time of each IGBT and the reference time. This provides a precise hardware measurement basis for subsequent differentiated trigger delay compensation of each module based on the actual action time difference data. Based on the precise feedback measurement capability provided by this device, even if the inherent action times of each IGBT are inconsistent due to manufacturing parameter dispersion and differences in drive circuit delays, the microcontroller can still make targeted adjustments to the trigger pulse emission time of each module according to the feedback data, making the actual conduction times of each IGBT tend to be consistent. This effectively eliminates the dynamic voltage unevenness caused by asynchronous operation of multi-stage series IGBTs, avoids overvoltage breakdown of IGBTs due to uneven voltage, and significantly improves the operational reliability and service life of the high-voltage electronic switching device in impulse withstand voltage tests and high-voltage on / off control. Attached Figure Description

[0055] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0056] Figure 1 This is a schematic diagram of the high-voltage electronic switching device according to an embodiment of the present invention;

[0057] Figure 2 This is a flowchart illustrating the steps of a control method applied to a high-voltage electronic switching device according to an embodiment of the present invention. Detailed Implementation

[0058] This invention provides a high-voltage electronic switching device and control method to solve the technical problem of asynchronous switching action caused by parameter dispersion and drive delay differences in multi-stage series IGBTs, resulting in dynamic voltage unevenness.

[0059] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] Please see Figure 1 The present invention provides a high-voltage electronic switch device, comprising a microcontroller and a multi-stage series IGBT switch module formed by connecting multiple IGBT switch modules in series.

[0061] Each IGBT switching module includes a trigger isolation optocoupler, a trigger circuit unit, an IGBT transistor, a voltage detection circuit unit, and a detection isolation optocoupler;

[0062] One end of the trigger isolation optocoupler is connected to the microcontroller;

[0063] The other end of the trigger isolation optocoupler is connected to one end of the trigger circuit;

[0064] The other end of the trigger circuit is connected to the gate of the IGBT transistor;

[0065] The input terminal of the voltage detection circuit unit is connected in parallel with the IGBT transistor;

[0066] The output terminal of the voltage detection circuit unit is connected to one end of the detection isolation optocoupler;

[0067] The other end of the detection isolation optocoupler is connected to the microcontroller.

[0068] In this embodiment of the invention, multiple IGBT switching modules (e.g., five in this embodiment, but the invention is not limited thereto) are connected in series to form a multi-stage series IGBT switching module for withstanding high voltage (e.g., each IGBT has a rated voltage of 5.8kV, and five in series can construct a 20kV high-voltage electronic switch). Each IGBT switching module includes an independent trigger isolation optocoupler, a trigger circuit unit, an IGBT, a voltage detection circuit unit, and a detection isolation optocoupler.

[0069] Its working principle is as follows:

[0070] When a closing operation is required, an STM32F4 microcontroller with a main frequency of at least 180MHz can be used. The microcontroller sends a trigger pulse electrical signal. This trigger pulse signal is first transmitted to the trigger isolation optocoupler of each IGBT switching module. The trigger isolation optocoupler converts the electrical signal into an optical signal, which passes through an electrical isolation strip and is then converted back into a trigger pulse electrical signal before being sent to the trigger circuit unit. This opto-isolation method effectively achieves electrical isolation between the control circuit and the high-voltage main circuit, ensuring the safety of the low-voltage control side.

[0071] After receiving the restored trigger pulse signal, the trigger circuit amplifies it to generate a gate drive voltage sufficient to turn on the IGBT, and applies it to the gate of the IGBT. Under the action of the gate drive voltage, the IGBT begins to conduct.

[0072] At the instant the IGBT is turned on, the voltage (Vce) between its collector and emitter drops rapidly, forming a voltage falling edge. At this moment, a voltage detection circuit unit connected in parallel with the IGBT captures this falling edge signal in real time. This falling edge signal is then sent to a detection isolation optocoupler. The optocoupler also converts this electrical signal into an optical signal, which, after passing through an electrical isolation strip, is converted back into an electrical signal and fed back to the microcontroller.

[0073] Because each IGBT switching module has an independent trigger isolation optocoupler and a detection isolation optocoupler, the microcontroller can accurately record the actual arrival time of the voltage falling edge of each IGBT during each closing operation. By comparing and analyzing the action times of each IGBT in multiple closing operations (e.g., 10 no-load closing tests), the microcontroller can accurately calculate the actual action time difference between each IGBT switching module. Based on this, the microcontroller can dynamically adjust the issuance time of the next trigger pulse, issuing the trigger pulse earlier for slower-acting modules and delaying the trigger pulse for faster-acting modules, thereby achieving fine-tuning compensation for the trigger time of each module. Since the microcontroller has a main frequency of no less than 180MHz, its minimum adjustable delay step can be accurate to 5.55ns (1 / 180MHz), enabling high-precision adjustment of the trigger time.

[0074] Through the closed-loop detection and dynamic compensation mechanism of "issuing trigger commands - real-time feedback of action timing" described above, the embodiments of the present invention can effectively eliminate the problem of asynchronous operation caused by factors such as the dispersion of parameters of each IGBT, the difference in drive circuit delay, and temperature changes, and control the actual closing action time difference of each IGBT within a very small range (e.g., less than 1 microsecond). This solves the problem of dynamic voltage unevenness caused by asynchronous operation of multi-stage series IGBTs, avoids overvoltage breakdown of a single IGBT due to excessive voltage, and significantly improves the operational reliability and service life of the high-voltage electronic switchgear in impulse withstand voltage tests and high-voltage on / off control. Simultaneously, because the voltage detection circuit units at each stage monitor the voltage status of the IGBT in real time, once an abnormal situation causes a momentary overvoltage in a certain IGBT, the system can respond promptly, providing accurate triggering basis for subsequent overvoltage protection measures (such as triggering the operation of parallel surge arresters), forming a dual protection mechanism combining active prevention and hardware fallback, further enhancing the safety of the device.

[0075] Microcontroller: refers to a microcontroller with a main frequency of not less than 180MHz, used to issue trigger pulses, receive feedback signals, and execute time difference calculation and compensation control logic.

[0076] IGBT switching module: refers to an independent power unit composed of a trigger isolation optocoupler, a trigger circuit unit, an IGBT transistor, a voltage detection circuit unit, and a detection isolation optocoupler. Multiple IGBT switching modules are connected in series to form a multi-stage series structure.

[0077] Multi-stage series IGBT switch module: refers to an overall structure composed of multiple IGBT switch modules connected end to end in series through the collectors and emitters of each stage of IGBT transistors, used to jointly bear high voltage.

[0078] Triggered isolation optocoupler: refers to an optocoupler device composed of a light-emitting device and a photosensitive device packaged together. It is used to convert electrical signals into light signals, pass them through an electrical isolation strip, and then convert them back into electrical signals, so as to achieve electrical isolation between low-voltage control circuits and high-voltage main circuits.

[0079] Trigger circuit unit: refers to the drive circuit used to amplify the power of the restored trigger pulse electrical signal and generate a gate drive voltage sufficient to drive the IGBT transistor to conduct.

[0080] IGBT: Insulated Gate Bipolar Transistor. As the main power switching device in high-voltage electronic switching devices, its collector and emitter are used in series for voltage division, and the gate is used to receive drive signals to realize on / off control.

[0081] Voltage detection circuit unit: refers to the detection circuit connected in parallel across the collector and emitter of the IGBT, used to capture the voltage drop edge transition signal at the instant the IGBT is turned on.

[0082] Detection isolation optocoupler: refers to an optocoupler device composed of a light-emitting device and a photosensitive device packaged together. It is used to convert the falling edge transition electrical signal output by the voltage detection circuit unit into an optical signal, which passes through the electrical isolation strip and is then restored to an electrical signal, so as to realize the high-speed isolated transmission of the feedback signal from the high-voltage side to the microcontroller on the low-voltage side.

[0083] Please see Figure 1 The present invention provides a high-voltage electronic switching device, wherein each IGBT switching module further includes an isolated independent power supply;

[0084] The trigger isolation optocoupler, trigger circuit unit, IGBT transistor, voltage detection circuit unit, and detection isolation optocoupler are all connected to an isolated independent power supply.

[0085] In this embodiment of the invention, each IGBT switching module is equipped with an independent isolated power supply. The input terminal of this isolated power supply is connected to the system auxiliary low-voltage power supply (e.g., a 24V DC bus), and its output terminal has a floating power supply capability that is isolated from the high-voltage main circuit potential. It is connected to the power ports of the trigger isolation optocoupler (high-voltage side), the trigger circuit unit, the IGBT transistor (drive logic side), the voltage detection circuit unit, and the detection isolation optocoupler (high-voltage side) within the module, respectively, to provide the power required for the operation of the above-mentioned units.

[0086] In a high-voltage topology with multiple IGBTs connected in series, each IGBT stage shares a different high potential during normal operation. The reference ground potential of each module floats on different high potentials depending on its series connection position, making a common ground impossible. In this invention, by configuring an independent isolated power supply for each IGBT switching module, all high-voltage side circuits within each module are powered and process signals based on the reference potential of the IGBT at that stage, thus achieving power supply self-consistency and electrical autonomy within the module. During triggering, when the microcontroller sends a trigger pulse, the trigger isolation optocoupler transmits the control signal from the low-voltage side to the high-voltage side. The independent isolated power supply of this module then provides driving energy to the trigger circuit unit, ensuring that the trigger circuit unit can output sufficient gate drive power to quickly turn on the IGBT. During detection, when the voltage detection circuit unit captures the voltage drop edge at the moment the IGBT turns on, its output signal is converted into an optical signal by the detection isolation optocoupler (high-voltage side), which is also powered by the independent isolated power supply, and transmitted to the low-voltage side. This avoids signal crosstalk or detection distortion between modules with different potentials due to the common ground problem.

[0087] Because the isolated independent power supplies achieve complete electrical isolation and independent floating power supply between each module level, the voltage detection circuit units at each level can accurately and independently capture the voltage falling edge signal of their respective IGBTs without common-mode interference. This signal is then fed back to the microcontroller in real time and without distortion via the detection isolation optocoupler, providing the microcontroller with clean and accurate raw data on the timing of each stage's operation. Simultaneously, since each trigger circuit unit receives an independent and stable power supply, its ability to drive the IGBT gate is unaffected by series potential changes, ensuring the consistency of the amplitude and rise rate of the gate drive voltage for each IGBT. Ultimately, this hierarchically independent isolated power supply architecture effectively improves the anti-interference capability and signal fidelity of the entire device in a multi-stage high-voltage series environment. It provides a stable and reliable hardware power supply foundation for the accurate measurement and dynamic compensation of the timing difference between each stage's operation in subsequent closed-loop synchronous control, ensuring the synchronization accuracy and long-term operational stability of the high-voltage electronic switchgear during impulse withstand voltage tests.

[0088] Isolated independent power supply: refers to an isolated power supply module with floating potential output capability that is independently configured for each stage of IGBT switching module. Its input terminal is connected to the system auxiliary low voltage power supply, and its output terminal is connected to the power port of the trigger isolation optocoupler, trigger circuit unit, IGBT tube, voltage detection circuit unit and detection isolation optocoupler in this module, so as to provide the above units with working power that is isolated from the high voltage main circuit potential.

[0089] Please see Figure 1 The present invention provides a high-voltage electronic switching device, wherein the trigger isolation optocoupler includes a trigger isolation transmitting optocoupler and a trigger isolation receiving optocoupler;

[0090] The input terminal of the trigger isolation emitter optocoupler is connected to the microcontroller;

[0091] The output of the trigger-isolated transmitting optocoupler is connected to the input of the trigger-isolated receiving optocoupler;

[0092] The output of the trigger isolation receiver optocoupler is connected to one end of the trigger circuit.

[0093] The detection isolation optical coupler includes the detection isolation transmitting optical coupler and the detection isolation receiving optical coupler;

[0094] The output of the voltage detection circuit unit is connected to the input of the detection isolation optocoupler;

[0095] The output terminal of the detection isolation transmitting optocoupler is connected to the input terminal of the detection isolation receiving optocoupler;

[0096] The output of the isolation receiving optocoupler is connected to the microcontroller.

[0097] In this embodiment of the invention, the trigger isolation optocoupler is specifically composed of a trigger isolation transmitting optocoupler and a trigger isolation receiving optocoupler paired together, and the detection isolation optocoupler is specifically composed of a detection isolation transmitting optocoupler and a detection isolation receiving optocoupler paired together. Thus, in each IGBT switching module, a forward drive isolation channel and a reverse detection isolation channel are respectively constructed.

[0098] For the forward drive isolation channel, the trigger isolation emitter optocoupler is located on the low-voltage side (closer to the microcontroller). Its input is connected to the PWM pulse output pin of the microcontroller to receive the trigger pulse electrical signal emitted by the microcontroller. The trigger isolation receiver optocoupler is located on the high-voltage side (closer to the trigger circuit). Its input is optically coupled to the output of the trigger isolation emitter optocoupler via an optical fiber or internal optical path, and its output is connected to the signal input of the trigger circuit unit. During operation, the trigger pulse electrical signal emitted by the microcontroller first drives the light-emitting device (such as a light-emitting diode) inside the trigger isolation emitter optocoupler to convert the electrical signal into an optical signal. After passing through the electrical isolation zone between the high and low voltage, the optical signal is received by the photosensitive device (such as a phototransistor) inside the trigger isolation receiver optocoupler and converted back into an electrical signal, which is then sent to the trigger circuit unit. Since the trigger signal crosses the isolation zone in the form of an optical signal and there is no direct electrical connection, when multiple IGBTs are connected in series, even if the IGBT switching modules of each stage are at different floating high potentials, the microcontroller on the low-voltage side can still safely and reliably transmit trigger commands to the trigger circuit unit on the high-voltage side without worrying about high voltage breaking down the low-voltage circuit.

[0099] For the reverse detection isolation channel, the detection isolation transmitter optocoupler is located on the high-voltage side (closer to the voltage detection circuit). Its input is connected to the output of the voltage detection circuit unit to receive the electrical signal representing the falling edge of the IGBT voltage at the moment of IGBT turn-on. The detection isolation receiver optocoupler is located on the low-voltage side (closer to the microcontroller). Its input is optically coupled to the output of the detection isolation transmitter optocoupler via an optical fiber or internal optical path, and its output is connected to the capture / interrupt input pin of the microcontroller. When the IGBT is turned on, its collector-emitter voltage drops rapidly. After the voltage detection circuit unit captures this falling edge transition, it outputs a corresponding electrical signal to the detection isolation transmitter optocoupler. This electrical signal is converted into an optical signal, passes through the isolation band, is received by the detection isolation receiver optocoupler, and is restored to an electrical signal. Finally, it is input to the high-speed timer capture pin of the microcontroller so that the microcontroller can record the actual arrival time of the falling edge of the IGBT voltage at this stage.

[0100] Through the aforementioned paired optocoupler structure, this invention establishes an independent, bidirectional isolated transmission channel in each IGBT switching module. The forward channel is responsible for safely transmitting the microcontroller's trigger command to the high-voltage side trigger circuit, while the reverse channel is responsible for feeding back the actual operating moment of the high-voltage side IGBT to the low-voltage side microcontroller in real time without distortion. Since the forward and reverse isolation channels of each stage are independent, the signal transmission between stages does not interfere with each other, avoiding the impact of ground interference and signal crosstalk on triggering and detection accuracy in multi-stage series high-voltage environments. Simultaneously, since the optocoupler's own transmission delay is fixed and measurable, the consistency difference in optocoupler transmission delay between stages can be eliminated through subsequent closed-loop compensation algorithms. This provides an accurate, reliable, and low-noise hardware signal transmission foundation for the high-precision closed-loop synchronous control system, ensuring that the microcontroller can accurately calculate the actual operating time difference between each IGBT based on real, synchronous feedback data, achieving microsecond-level synchronous control.

[0101] Trigger-isolated emitter optocoupler: This refers to the light-emitting device part of the trigger-isolated optocoupler located on the low-voltage side (closer to the microcontroller side). Its input terminal is connected to the PWM pulse output pin of the microcontroller and is used to convert the trigger pulse electrical signal into a trigger pulse optical signal.

[0102] Trigger-isolated receiving optocoupler: refers to the photosensitive device part of the trigger-isolated optocoupler located on the high-voltage side (close to the trigger circuit side). Its input end is optically coupled to the output end of the trigger-isolated transmitting optocoupler through an optical fiber or internal optical path. It is used to receive the trigger pulse optical signal and restore it to the trigger pulse electrical signal and send it to the trigger circuit unit.

[0103] Detection isolation optocoupler: refers to the light-emitting device part of the detection isolation optocoupler located on the high-voltage side (closer to the voltage detection circuit). Its input terminal is connected to the output terminal of the voltage detection circuit unit, and it is used to convert the falling edge switching electrical signal into an optical signal.

[0104] Detection isolation receiving optocoupler: refers to the photosensitive device part set on the low-voltage side (closer to the microcontroller) of the detection isolation optocoupler. Its input end is optically coupled to the output end of the detection isolation transmitting optocoupler through an optical fiber or internal optical path. It is used to receive optical signals and restore them to falling edge switching electrical signals and send them to the capture / interrupt input pin of the microcontroller.

[0105] Please see Figure 1 The present invention provides a high-voltage electronic switching device, wherein each IGBT switching module further includes a surge arrester;

[0106] The surge arrester is connected in parallel with the IGBT tube.

[0107] In this embodiment of the invention, each IGBT switching module is further equipped with a surge arrester, which is connected in parallel across the collector and emitter of the IGBT in that stage. The surge arrester is a metal oxide surge arrester (MOA), and its activation voltage is configured to match the actual operating voltage of the IGBT. For example, in this embodiment, the actual operating voltage of each IGBT is controlled at 4kV, so the activation voltage of the surge arrester is set to 4000V. In multi-stage series-connected IGBT high-voltage electronic switching devices, although each IGBT achieves microsecond-level precision synchronous operation through a closed-loop synchronous control method, under extreme conditions (such as lightning surges, load mutations, or extreme electromagnetic interference), instantaneous overvoltage spikes exceeding the software closed-loop response speed may still occur within a very short time. At this time, the surge arrester connected in parallel between the collector and emitter of the IGBT stage will, once it detects that the voltage across its terminals exceeds the preset 4000V activation threshold, rapidly switch its internal nonlinear resistive varistor from a high-resistance state to a low-resistance conducting state. This provides a low-impedance bypass discharge path for the overvoltage energy, quickly absorbing and dissipating the overvoltage spike energy as heat. This clamps the instantaneous voltage across the IGBT stage within a safe level of 4000V, effectively preventing the IGBT from breaking down due to instantaneous overvoltage. After the overvoltage spike passes, the surge arrester automatically returns to a high-resistance state, without affecting the normal operation of the circuit.

[0108] In this invention, the surge arrester constitutes a purely hardware-level protection mechanism independent of software closed-loop control. This protection mechanism does not rely on microcontroller response, optocoupler transmission, or trigger circuit action; it relies entirely on the surge arrester's own nonlinear volt-ampere characteristics to achieve instantaneous response. Its action time is typically in the nanosecond range, far faster than the microsecond-level response speed of software closed-loop control. Therefore, when the instantaneous voltage across a certain IGBT exceeds 4000V due to trigger delay or other abnormal factors, the surge arrester can act before the software closed loop intervenes, absorbing surge energy and providing hardware-level safety fallback protection for the IGBT. This complementary combination of hardware protection and software closed-loop control constructs a dual safety guarantee system for the high-voltage electronic switching device of this invention, providing both active prevention and passive fallback: Under normal operating conditions, closed-loop synchronous control eliminates dynamic voltage imbalance at the source, preventing overvoltage; under extreme abnormal operating conditions, the surge arrester, as the last line of defense, provides nanosecond-level hardware protection at the moment of overvoltage, effectively ensuring the safety of the IGBT tube and further improving the reliability and fault tolerance of the device in harsh application scenarios such as impulse withstand voltage tests and high-voltage switching control.

[0109] Surge arrester: refers to a metal oxide surge arrester (MOA), which is connected in parallel to the collector and emitter of the IGBT. Its start-up voltage is configured to match the actual operating voltage of the IGBT (e.g., 4000V). It is used to automatically turn on when the IGBT is subjected to instantaneous overvoltage to absorb surge energy and provide hardware-level overvoltage protection.

[0110] Please see Figure 2 The present invention provides a control method for a high-voltage electronic switching device, comprising:

[0111] Step 101: Control each IGBT switch module to perform multiple no-load closing tests to obtain the corresponding actual closing time difference data.

[0112] IGBT: Insulated Gate Bipolar Transistor.

[0113] Furthermore, the multiple no-load closing tests specifically include:

[0114] One of the multiple IGBT switching modules is pre-set as the reference IGBT tube;

[0115] Under no-load conditions, trigger pulse electrical signals are simultaneously sent to multiple IGBT switching modules;

[0116] The control trigger isolation optocoupler converts the trigger pulse electrical signal into a trigger pulse optical signal, which passes through the isolation strip, and then is restored to the trigger pulse electrical signal and sent to the trigger circuit unit;

[0117] The control trigger circuit unit amplifies the restored trigger pulse electrical signal to drive the IGBT transistor to conduct.

[0118] The control voltage detection circuit unit captures the falling edge jump signal of the IGBT in real time and sends it to the detection isolation optocoupler;

[0119] The control and detection isolation optocoupler converts the falling edge jump signal into an optical signal that passes through the isolation strip, and then restores it to the falling edge jump signal;

[0120] Edge capture is performed on the restored falling edge jump signal to record the actual arrival time of the falling edge of each IGBT transistor.

[0121] The actual arrival time of the voltage drop edge of the reference IGBT in each closing test is used as the reference time. The actual arrival time of each IGBT is subtracted from the reference time to obtain the actual closing time difference under a single no-load closing test.

[0122] By integrating the actual closing time differences under all no-load closing tests, the actual closing time difference data corresponding to each IGBT switch module is obtained.

[0123] In this embodiment of the invention, any one of the multiple IGBT switching modules is pre-set as the reference IGBT. Specifically, assuming the system has N levels of IGBT switching modules (e.g., N=5), the first level IGBT switching module is used as the time reference, and its theoretical closing delay value is set to 0. The actual closing times of the remaining IGBT switching modules are measured with reference to this reference level. Once this reference level is set, it remains unchanged throughout the no-load closing test and subsequent load operation to ensure that all measurement data have a unified reference system.

[0124] Under no-load conditions, i.e., when the high-voltage main circuit is not under 20kV, the microcontroller simultaneously sends trigger pulse signals to multiple IGBT switching modules. Since this is the no-load closing test phase, each IGBT has not yet been subjected to the high voltage of the main circuit. Therefore, even if there are differences in the timing of the action of each IGBT due to parameter dispersion, it will not cause damage to the devices, thus providing a safe test environment for time difference measurement.

[0125] Subsequently, the trigger pulse electrical signal issued by the microcontroller is transmitted to the trigger isolation optocouplers of each module. The trigger isolation optocoupler converts the trigger pulse electrical signal into a trigger pulse optical signal, which crosses the electrical isolation band between the high and low voltage levels, and is then converted back into a trigger pulse electrical signal by the trigger isolation optocoupler and transmitted to the trigger circuit unit. In this process, because the trigger signal crosses the isolation band in the form of an optical signal, effective electrical isolation between the low-voltage control circuit and the high-voltage suspension circuit is achieved.

[0126] After receiving the restored trigger pulse signal, the trigger circuit unit amplifies it to generate a gate drive voltage sufficient to turn on the IGBT, and applies it to the gate of the IGBT to turn it on. Due to parameter variations in each IGBT stage during manufacturing, and slight differences in the response speeds of the trigger isolation optocouplers and trigger circuit units at each stage, the actual turn-on times of each IGBT stage are not entirely consistent, even if the microcontroller sends trigger pulses simultaneously; a certain time deviation exists.

[0127] At the instant the IGBT is turned on, the voltage (Vce) between its collector and emitter drops rapidly, generating a falling edge signal. At this moment, a voltage detection circuit unit connected in parallel with the IGBT captures this falling edge signal in real time and sends it to a detection isolation optocoupler. The optocoupler converts this falling edge signal into an optical signal, which, after passing through an isolation strip, is restored to a falling edge signal and sent to the microcontroller's capture / interrupt input pin.

[0128] The microcontroller (such as the STM32F4 microcontroller with a main frequency of not less than 180MHz) uses its internal high-precision timer to capture the edge of the restored falling edge transition signal and record the actual arrival time of the falling edge transition signal of each IGBT stage. This actual arrival time corresponds to the physical moment when each IGBT stage actually completes conduction in this closing test, and is the core basis for measuring the synchronization of each stage's operation.

[0129] Since the microcontroller uses the actual arrival time of the voltage drop edge of the reference IGBT during each closing test as the reference time, after each no-load closing test, the microcontroller automatically subtracts the actual arrival time of each IGBT from the reference time to obtain the actual closing time difference for a single no-load closing test. This actual closing time difference reflects the actual operating time offset of each IGBT relative to the reference IGBT during this closing test.

[0130] Repeat the above closing test process M times (e.g., M=10 times), recording the actual closing time difference of each IGBT stage relative to the reference stage for each closing test. After all no-load closing tests are completed, the microcontroller integrates the actual closing time differences of each IGBT stage from the M closing tests to obtain the actual closing time difference data corresponding to each IGBT switching module. For example, for the first... The raw data obtained from the M closing tests of the IGBT transistor is as follows: ,in Indicates the first IGBT tube in the first stage The actual closing time difference relative to the reference level in the secondary closing test. This set of raw data includes both fixed hardware delay components determined by the inherent characteristics of each stage of trigger isolation optocoupler, trigger circuit unit, and IGBT transistor, and random jitter drift components caused by environmental factors such as temperature changes, power supply ripple, and measurement noise.

[0131] Through the aforementioned multiple no-load closing tests, this invention provides a comprehensive raw data foundation for subsequent time delay filtering and compensation calculations. Since each closing test is performed independently, and the IGBTs at each stage do not experience high-voltage stress under no-load conditions, a large number of actual operating time difference samples can be obtained without damaging the devices. This provides sufficient statistical data support for subsequent steps to filter out random jitter drift through arithmetic averaging and accurately extract the fixed hardware delay of each IGBT stage. Simultaneously, because the voltage detection circuit units at each stage and the detection isolation optocouplers can capture and feedback the actual arrival time of the voltage falling edge of each IGBT stage in real time, the actual closing time difference data acquired by the microcontroller has the advantages of high precision, low latency, and no common-ground interference, thus laying a solid data acquisition foundation for high-precision closed-loop synchronous control.

[0132] Step 102: Calculate the average fixed delay corresponding to each IGBT switch module using actual closing time difference data.

[0133] In this embodiment of the invention, after completing the M no-load closing tests in step 101, the microcontroller has collected M actual closing time difference data for each IGBT switching module. Specifically, for the first... The raw data obtained from the M closing tests of the IGBT switching module is denoted as follows: ,in Indicates the first The first stage IGBT switching module is in the first stage. The actual closing time difference relative to the reference IGBT in the secondary closing test. This set of raw data contains two types of physical components: one is the fixed hardware delay component determined by the inherent physical characteristics such as the transmission delay of each stage of trigger isolation optocoupler, the response delay of the trigger circuit unit, and the turn-on delay of the IGBT itself; the other is the random jitter drift component caused by environmental factors such as temperature changes, isolation independent power supply ripple, electromagnetic interference, and measurement noise.

[0134] In order to accurately extract the fixed delay component determined by the inherent characteristics of the hardware from the above raw data, the microcontroller performs the following steps: The arithmetic mean of the M actual closing time differences of the IGBT switching module is calculated using the following formula:

[0135] ;

[0136] in, For the first The average fixed delay of the IGBT switching module is as follows: The total number of no-load closing tests is preset (M=10 in this embodiment). This calculation process is automatically completed by the microcontroller in the internal timer capture interrupt service routine. All raw data is stored in the microcontroller's internal RAM or non-volatile memory to ensure that data is not lost during multiple closing tests.

[0137] The core principle of the aforementioned arithmetic averaging process lies in the fact that the random jitter drift component follows a normal or approximately normal distribution with a mean of zero. When the number of measurements M is sufficiently large, the algebraic sum of the random jitter components in the M measurements approaches zero. Therefore, by performing an arithmetic average on the M actual closing time difference data, the microcontroller can effectively filter out random fluctuations caused by temperature changes, power supply ripple, device aging, and measurement noise, obtaining a fixed hardware delay estimate that approximates the true physical characteristics of the channel. The average fixed delay Essentially characterizes the first The inherent physical delay in the complete link from the microcontroller sending the trigger pulse to the actual conduction of the IGBT in the stage of the IGBT switching module is determined by the transmission delay of the trigger isolation optocoupler in the module, the response time of the trigger circuit unit, and the turn-on delay of the IGBT itself.

[0138] Through the above processing, each IGBT switching module obtains an average fixed delay that has been averaged multiple times and filtered out for random fluctuations. This value serves as a core parameter characterizing the inherent delay characteristics of each channel, providing a precise, stable, and reliable mathematical basis for calculating the relative compensation between each channel in subsequent steps. Since this average fixed delay truly reflects the intrinsic delay differences of each IGBT switching module at the hardware level, the compensation calculated accordingly can fundamentally eliminate the asynchronous operation problem caused by the discreteness of device parameters and differences in drive circuits, without causing incorrect compensation direction due to random errors in a single measurement, thus ensuring the stability and robustness of the closed-loop synchronous control system. Furthermore, the arithmetic averaging algorithm itself has low computational complexity and is simple to implement. Under hardware conditions where the STM32F4 microcontroller's main frequency is not lower than 180MHz, the average delay calculation for all 5 channels can be completed within microseconds without placing any additional burden on the system's real-time response performance.

[0139] Step 103: Evaluate the discreteness of each actual closing time difference data.

[0140] Furthermore, step 103 may include the following sub-steps:

[0141] S11. Calculate the standard deviation of each actual closing time difference data;

[0142] S12. If all standard deviations are less than the preset qualified threshold, the dispersion assessment result is deemed qualified.

[0143] S13. If any standard deviation is not less than the preset acceptable threshold, the dispersion assessment result is deemed unacceptable.

[0144] In this embodiment of the invention, after the microcontroller completes the calculation of the average fixed delay for each stage in step 102, it simultaneously calculates the standard deviation of the actual closing time difference data for each stage. For the first... The stage IGBT switching module has M actual closing time difference data obtained from M no-load closing tests. The average fixed delay of this stage is calculated in step 102. The microcontroller calculates the standard deviation of the raw data for this stage using the following formula:

[0145] ;

[0146] in, For the first The standard deviation of the first-stage IGBT switching module. This standard deviation characterizes the performance of the first-stage IGBT switching module. The dispersion of the actual closing time difference measured in each of the M independent no-load closing tests of the IGBT switching module relative to its average value is considered; that is, the magnitude of the random jitter drift during each operation of the channel. The microcontroller sequentially iterates through all N-stage IGBT switching modules (N=5 in this embodiment) and calculates the standard deviation for each stage. .

[0147] The microcontroller's internal memory stores a preset pass threshold. The threshold is preset by those skilled in the art based on the system's synchronization accuracy requirements, the signal-to-noise ratio characteristics of the voltage detection circuit unit and the detection isolation optocoupler, and practical engineering experience. For example, in this embodiment, if the target synchronization accuracy is less than 1 microsecond, the preset qualified threshold can be set to 100 nanoseconds or 200 nanoseconds. The microcontroller compares all N standard deviations calculated in step S11 with the preset qualified threshold one by one. If all standard deviations are less than the preset qualified threshold, it indicates that the IGBT switching modules at each level have good consistency in action during multiple no-load closing tests, the random jitter drift component contained in the original data is small, and the average fixed delay calculated in step 102 has sufficient representativeness and reliability. Based on this, the microcontroller determines that the discreteness evaluation result is qualified and allows the process to proceed to the subsequent compensation calculation step.

[0148] If the standard deviation of at least one IGBT switching module is greater than or equal to the preset acceptable threshold, it indicates that the actual closing time difference measured in each of the multiple no-load closing tests of that IGBT switching module fluctuates drastically, with excessive random jitter drift. Potential causes of this phenomenon may include: excessive output ripple of the isolated independent power supply leading to instability in the trigger circuit and voltage detection circuit units; insufficient signal-to-noise ratio of the voltage detection circuit unit resulting in inaccurate edge capture of the falling edge transition signal; or severe electromagnetic interference within the device affecting the signal transmission quality of the detection isolation optocoupler. In this case, since an excessively large standard deviation means that the random jitter component of this channel has significantly affected the reliability of the measurement data, directly calculating the compensation amount based on this unreliable average fixed delay will not only fail to effectively eliminate the operating time difference between each IGBT stage, but may also further deteriorate the synchronization performance due to incorrect compensation direction or amount. Therefore, the microcontroller determines that the discreteness assessment result is unqualified and immediately suspends the subsequent compensation process. It outputs a fault indication signal through its alarm output pin to prompt the maintenance personnel to check and improve the hardware circuit (such as detecting the ripple of the isolated independent power supply, checking for electromagnetic interference sources, adjusting the filtering parameters of the voltage detection circuit unit, etc.). After the hardware is checked and repaired, steps 101 to 103 are executed again until the standard deviation of all channels falls back to the preset qualified threshold range.

[0149] Through the aforementioned discreteness evaluation mechanism, this invention rigorously verifies the reliability of the actual closing time difference data collected in step 101 before formally performing the load-bearing closing operation. This prevents unreliable data caused by excessive random interference from being preemptively included in the compensation calculation, thus avoiding negative impacts on system synchronization performance caused by erroneous compensation amounts calculated based on unreliable data. This evaluation mechanism acts as a safety gating mechanism for the control system process, ensuring that only verified, stable, and reliable data can proceed to the subsequent compensation amount determination step, thereby guaranteeing the stability, safety, and reliability of the closed-loop synchronous control system from the source. Simultaneously, when the standard deviation exceeds the limit, the system can proactively issue an alarm and indicate the direction of hardware troubleshooting, providing maintenance personnel with clear fault diagnosis criteria and significantly improving the system's maintainability and engineering practicality.

[0150] Step 104: When the discreteness evaluation result is qualified, the channel compensation amount corresponding to each IGBT switching module is determined by using the average fixed time delay.

[0151] Furthermore, step 104 may include the following sub-steps:

[0152] S21. When the discreteness evaluation result is qualified, select the maximum value from all average fixed delays as the maximum average fixed delay.

[0153] S22. Subtract each average fixed delay from the maximum average fixed delay to obtain the channel compensation amount corresponding to each IGBT switching module.

[0154] Among them, the channel compensation amount is the advance trigger time corresponding to the maximum average fixed delay of each IGBT switching module.

[0155] In this embodiment of the invention, after confirming that the standard deviation of each IGBT switching module in step 103 is less than a preset qualified threshold, the microcontroller reads the average fixed delay of each IGBT switching module calculated in step 102. The microcontroller, through internal comparison calculations, finds the largest value among the above N average fixed delays and marks it as the maximum average fixed delay. The IGBT switching module corresponding to this maximum average fixed delay is the channel with the largest inherent hardware delay in the entire series link, that is, the stage with the slowest physical operation.

[0156] After determining the maximum average fixed delay, the microcontroller subtracts it from the average fixed delay of each IGBT switching module. The calculation formula is as follows:

[0157] ;

[0158] in, For the first The channel compensation amount corresponding to the IGBT switching module. This is the maximum average fixed delay selected in step S21. The physical meaning of this channel compensation amount is: the first... The IGBT switching module needs to be triggered earlier than the trigger reference time for the next time. A trigger pulse is emitted at a specific time. For The corresponding level (i.e., the slowest channel) has the following compensation amount. This indicates that this channel does not need to be prioritized as the trigger time anchor point for the entire serial link; for the other channels, since... Its compensation amount This means that the faster channels need to be pre-connected by a certain amount of time to allow the slowest channel to complete its conduction.

[0159] Through the aforementioned relative alignment compensation strategy, this invention does not rely on the stability of an external absolute reference time. Instead, it uses the channel with the slowest physical action in each IGBT switching module as a natural reference anchor point, advancing the trigger time of all other channels to align with this slowest channel. This strategy has significant robustness advantages: regardless of whether the absolute value of the average fixed delay of each stage drifts due to factors such as temperature and aging, as long as the relative difference between each stage remains stable, the microcontroller can compensate based on... The calculated compensation amount can always accurately compensate for the inherent time difference between each stage, and the compensation accuracy will not be affected by changes in the external environment or minor fluctuations in the reference channel itself. Meanwhile, since the microcontroller's main frequency is no less than 180MHz and the minimum adjustable delay step is accurate to 5.55ns (1 / 180MHz), the calculated compensation amount can be converted into actual pulse delay with an accuracy far exceeding 1 microsecond. This ensures that the actual closing action time difference of each IGBT stage is compressed to the theoretical minimum, stably meeting the engineering specification of less than 1 microsecond. Ultimately, this relative alignment compensation strategy provides a reliable and efficient solution for achieving high-precision synchronous triggering of multi-stage series IGBTs with minimal computational overhead and the strongest environmental adaptability.

[0160] In an optional embodiment, when the discreteness evaluation result is qualified, the theoretical reference trigger time of the reference-level IGBT is obtained;

[0161] Subtract each average fixed delay from the theoretical benchmark trigger time to obtain the channel compensation amount corresponding to each IGBT switching module.

[0162] Among them, the channel compensation amount is the absolute trigger time value of each IGBT switching module relative to the theoretical reference trigger time.

[0163] In this embodiment of the invention, in step 104, when the discreteness evaluation result is qualified, the microcontroller uses the absolute compensation method to determine the channel compensation amount corresponding to each IGBT switching module. Specifically, the microcontroller first obtains the theoretical reference trigger time of the reference-level IGBT. The theoretical benchmark trigger time The absolute time reference value for the theoretically required trigger pulse, determined by the microcontroller based on the external closing command, is generated in real-time by the microcontroller's internal timer according to the system clock and the arrival time of the closing command. Subsequently, the microcontroller subtracts the average fixed delay of each IGBT switching module from the theoretical reference trigger time to obtain the channel compensation amount corresponding to each IGBT switching module. The calculation formula is as follows:

[0164] ;

[0165] in, For the first The channel compensation amount corresponding to the IGBT switching module. This is the theoretical reference trigger time for the reference-level IGBT. In this embodiment, the channel compensation amount... The physical meaning of is: the first When the IGBT switching module is triggered again, its trigger pulse should be emitted at the absolute moment on the actual physical timeline. In other words, the trigger pulses of each IGBT switching module are not emitted at the same time, but rather according to their respective calculated times. Each IGBT is independently activated to ensure that, after taking into account the inherent hardware delay differences at each stage, all IGBTs can be turned on at the same absolute moment.

[0166] The core advantage of the absolute compensation method described above is that the trigger pulse timing of each IGBT switching module is based on the same external theoretical benchmark. For independent calibration, the trigger time of each channel has a clear and unique definition on the absolute time axis. This strategy is suitable for applications that require strict alignment of the actual closing time of each IGBT stage to a specific external absolute time, such as situations requiring strict phase-locking with an external system clock or synchronization signal. Simultaneously, due to the channel compensation amount of each stage... Each stage of the system is independently calculated and loaded, with compensation at each level not affecting each other. Even if one channel is bypassed or isolated due to a fault, the remaining channels can still operate independently according to their predetermined trigger times, demonstrating high fault tolerance and flexibility overall. Furthermore, due to the absolute compensation method... All values ​​are relative to the same theoretical benchmark. At the absolute moment, when the system needs to adjust the trigger phase as a whole (e.g., delay or advance the entire closing action), the microcontroller only needs to adjust... The trigger time for all channels will automatically follow the given value. Synchronous offset eliminates the need to recalculate compensation amounts at each stage, significantly simplifying the control logic and computational overhead in dynamic phase-shifting scenarios. Based on this, the absolute compensation method proposed in this embodiment provides a high-precision, highly flexible, and easily integrated synchronous triggering solution for high-voltage electronic switching devices. Together with the aforementioned relative compensation method embodiment, it constitutes two compensation strategy systems that can be selectively used or adaptively switched according to operating conditions, further expanding the adaptability of this invention to different application scenarios.

[0167] Step 105: Perform a load-bearing closing operation on each IGBT switch module according to the compensation amount of each channel.

[0168] In this embodiment of the invention, in step 105, after the microcontroller completes the calculation of the channel compensation amount corresponding to each IGBT switch module in step 104, it loads the channel compensation amount into the pulse generation register of its internal timer and performs a load-bearing closing operation.

[0169] Specifically, the microcontroller contains multiple independent high-precision timer channels (such as the advanced timers TIM1 and TIM8 of the STM32F4 microcontroller), each corresponding to the trigger pulse output of a first-level IGBT switching module. The microcontroller first converts the compensation amounts calculated in step 104 into timer comparison matching values. In relative compensation mode, the channel compensation amount is the advance trigger time of each IGBT switching module relative to the slowest channel. The microcontroller subtracts the reference trigger time and loads it into the comparison register of the corresponding timer channel. In absolute compensation mode, the channel compensation amount is the absolute emission time of the trigger pulse of each IGBT switching module. The microcontroller directly converts the channel compensation amount into the initial timer count value and loads it into the comparison register of the corresponding channel. Since the microcontroller's main frequency is no less than 180MHz, its timer counting clock frequency is 180MHz, and the minimum adjustable delay step is accurate to 5.55ns (1 / 180MHz), the compensation amounts of each channel can be converted into physical pulse delays with a time resolution better than 5.55ns.

[0170] When the microcontroller receives an external load-bearing closing command, its internal timer starts counting. During the counting process, each timer channel independently outputs a trigger pulse at its set trigger time based on a pre-loaded comparison matching value. These trigger pulses are converted into optical signals by the trigger isolation optocouplers of each IGBT switching module, pass through the isolation strip, and are then restored to trigger pulse electrical signals and sent to the trigger circuit unit. The trigger circuit unit amplifies the restored trigger pulse electrical signals and drives the IGBTs to conduct at the preset compensation time. Since the output time of each trigger pulse has been differentiated according to the channel compensation amount calculated in step 104, the faster-acting channels are delayed in triggering, and the slower-acting channels are triggered earlier. Therefore, after the inherent hardware delay of each IGBT and the differentiated trigger delay cancel each other out, the actual closing action time of each IGBT tends to be consistent, and the actual closing time difference between each stage is compressed to within microseconds, stably meeting the engineering specification of less than 1 microsecond.

[0171] During the load-bearing closing operation, each voltage detection circuit unit still captures the voltage drop edge of its respective IGBT transistor at the moment of conduction in real time, and feeds it back to the microcontroller via the detection isolation optocoupler. The microcontroller compares the actual closing time difference data with the expected target to verify whether the synchronization accuracy is consistently stable within a range of less than 1 microsecond. If the actual closing time difference deviates slightly due to temperature drift, device aging, or other environmental factors, the microcontroller adds the actual time difference data acquired during the load-bearing closing operation to the historical sample pool, replaces the oldest data using a sliding window update strategy, and recalculates the average fixed delay and channel compensation amount before the next closing operation to achieve dynamic adaptive updating of the compensation parameters. Thus, the high-voltage electronic switchgear can continuously optimize the triggering synchronization accuracy of each IGBT transistor in a closed-loop iterative manner during each load-bearing closing operation, ensuring that the closing time difference is stably maintained at less than 1 microsecond throughout the entire service life.

[0172] Meanwhile, during load closing operations, if the instantaneous voltage across a certain IGBT exceeds 4000V due to lightning surges, sudden load changes, or other extreme interference, the surge arrester (metal oxide arrester, MOA) connected in parallel between the collector and emitter of that IGBT will automatically conduct, providing a low-impedance bypass discharge path for the overvoltage energy. This rapidly absorbs and dissipates the overvoltage spike energy, clamping the instantaneous voltage across the IGBT within a safe level. The arrester's action is a purely hardware-level response independent of software control, with an action time typically in the nanosecond range, far faster than the microsecond-level response speed of software closed-loop control. Therefore, even in extreme transient processes where software closed-loop control has not yet intervened, the arrester can still provide reliable "safety fallback protection" for the IGBT at the hardware level, forming a dual safety guarantee system of active prevention and passive fallback together with the aforementioned high-precision closed-loop synchronous control method.

[0173] Through the execution of step 105 above, this invention successfully applies the channel compensation amount calculated based on the no-load closing test in steps 101 to 104 to the actual load closing operation, enabling microsecond-level high-precision synchronous conduction of IGBTs at each stage in a multi-stage series high-voltage environment. This effectively eliminates the dynamic voltage unevenness caused by factors such as the parameter dispersion of each IGBT stage, the difference in drive circuit delay, and temperature drift, and avoids overvoltage breakdown of a single IGBT due to excessive voltage. This significantly improves the operational reliability and service life of the high-voltage electronic switchgear in impulse withstand voltage tests and high-voltage switching control. Simultaneously, because the voltage detection circuit units and detection isolation optocouplers at each stage continuously operate and provide real-time feedback on the actual action time difference during load closing, the system can continuously track and compensate for new deviations introduced by environmental changes and device aging in a closed-loop iterative manner, ensuring the long-term stability of synchronization accuracy. This provides a highly reliable and high-precision series IGBT electronic switchgear solution for impulse withstand voltage tests of high-voltage power equipment.

[0174] Actual closing time difference data: refers to the set of raw data that characterizes the time offset between the actual action time of each IGBT switch module and the reference IGBT tube, measured in multiple no-load closing tests.

[0175] Average fixed delay: refers to the arithmetic mean of multiple actual closing time difference data measured in multiple no-load closing tests of a certain IGBT switching module. It is used to characterize the fixed hardware delay of the channel determined by the inherent physical characteristics such as the transmission delay of the trigger isolation optocoupler, the response delay of the trigger circuit unit, and the turn-on delay of the IGBT tube itself.

[0176] Discreteness assessment: refers to the process of calculating the standard deviation of the actual closing time difference data of each IGBT switching module and comparing the standard deviation with the preset qualified threshold to determine the reliability of the original data and the stability of the system.

[0177] Channel compensation amount: refers to the time parameter that needs to be adjusted in terms of the timing of trigger pulse issuance in order to make the actual closing action time of each stage of the IGBT switch module more consistent during the next load closing operation.

[0178] Under load closing operation: refers to applying differentiated trigger pulses to each stage of the IGBT switching module according to the channel compensation amount under the condition that the working voltage (e.g., 20kV) has been applied to the high voltage main circuit, so that each stage of the IGBT tube performs the closing and conduction process under actual voltage and current conditions.

[0179] Reference-level IGBT: This refers to the first-level IGBT that is pre-set as a time reference in multiple IGBT switching modules. Its theoretical closing time delay is set to 0, and the actual closing time difference of the other IGBTs is measured with reference to this reference level.

[0180] No-load state: refers to the test state in which no working voltage (e.g., 20kV) is applied to the high-voltage main circuit. It is used to perform multiple closing tests under low-voltage safety conditions to obtain the actual operating time difference data of each IGBT tube.

[0181] Trigger pulse electrical signal: refers to the control level signal issued by the microcontroller to control the conduction of the IGBT transistor.

[0182] Falling edge jump signal: refers to the edge jump signal generated by the rapid drop in voltage between the collector and emitter of the IGBT at the moment of conduction.

[0183] Edge capture: refers to the operation of a microcontroller using its internal high-precision timer to perform hardware-level latching and timestamp recording on the restored falling edge transition signal.

[0184] Actual arrival time: refers to the timestamp value recorded by the microcontroller when the voltage falling edge transition signal of each IGBT is captured by the edge during each closing test.

[0185] Reference time: refers to the actual arrival time of the voltage drop edge of the reference stage IGBT in each closing test, and is used as the reference zero point for calculating the actual closing time difference of each stage in this closing test.

[0186] Maximum average fixed delay: refers to the maximum value selected from the average fixed delay of all IGBT switching modules. The corresponding IGBT switching module is the channel with the largest fixed hardware delay in the entire series link, that is, the stage with the slowest physical action.

[0187] Early trigger time: refers to the time that other IGBT switching modules at each level need to send a trigger pulse in advance relative to the slowest channel, with the IGBT switching module corresponding to the maximum average fixed delay as the reference anchor point. Its value is equal to the maximum average fixed delay minus the average fixed delay of the channel itself.

[0188] Theoretical reference trigger time: refers to the absolute time reference value that the microcontroller should theoretically issue as determined by the external closing command. It is generated in real time by the internal timer based on the system clock and the arrival time of the closing command.

[0189] Absolute trigger time value: refers to the absolute time on the physical time axis when the trigger pulse of each IGBT switching module is triggered again. Its value is equal to the theoretical reference trigger time minus the average fixed delay of the channel itself.

[0190] Standard deviation: refers to the statistical quantity that quantifies the dispersion of multiple actual closing time difference data measured in multiple no-load closing tests of a certain IGBT switching module relative to its average value. The larger the value, the more severe the random jitter and drift of the channel.

[0191] Preset qualified threshold: refers to the upper limit of the standard deviation stored in the microcontroller's internal memory. It is used to determine whether the dispersion of the actual closing time difference data of each stage is within an acceptable range. If all standard deviations are less than the threshold, the dispersion assessment result is deemed qualified.

[0192] This invention has the following advantages:

[0193] First, this invention achieves extremely high synchronization accuracy. In existing technologies, multi-stage IGBT series connection mainly relies on passive measures such as static equalizing resistors or RC snubber networks to improve voltage distribution. However, these measures cannot fundamentally solve the problem of asynchronous triggering caused by factors such as the dispersion of IGBT parameters at each stage, differences in drive circuit delays, and temperature drift. This invention constructs a complete closed-loop detection link of "issuing trigger commands - real-time feedback of action timing" by setting independent trigger isolation optocouplers and voltage detection circuit units and detection isolation optocouplers in each IGBT switching module. The microcontroller obtains the actual closing time difference data of each IGBT relative to the reference stage based on multiple no-load closing tests. After filtering out random jitter by arithmetic averaging, it determines the compensation amount of each channel using either a relative alignment method (using the slowest channel as the reference, with corresponding compensation amounts for the remaining channels in advance) or an absolute alignment method (using the theoretical reference trigger time as a reference, with each channel independently calculating the absolute trigger time). Furthermore, it adjusts the pulse delay based on a minimum adjustable delay step of 5.55ns provided by a main frequency of no less than 180MHz. This mechanism controls the actual closing action time difference of each IGBT to within 1 microsecond, eliminating the dynamic voltage imbalance caused by asynchronous operation from the source, and avoiding overvoltage breakdown of IGBT due to uneven voltage. Its synchronization accuracy is significantly better than the existing solution that relies on a passive voltage equalization network.

[0194] Secondly, this invention establishes a dual safety guarantee system combining proactive prevention and passive fallback. Existing passive voltage equalization measures only function effectively under steady-state conditions and cannot cope with nanosecond-level overvoltage spikes generated under extreme conditions such as lightning surges and sudden load changes. This invention, on the one hand, prevents dynamic voltage imbalance from the source through closed-loop synchronous control; on the other hand, it connects a 4000V starting voltage metal oxide surge arrester in parallel across each IGBT stage, forming a precise match with the IGBT's rated voltage of 5.8kV and actual operating voltage of 4kV. When extreme interference causes a certain IGBT stage to experience a momentary overvoltage exceeding 4000V, the MOA automatically conducts within nanoseconds, rapidly absorbing and dissipating the overvoltage spike energy, clamping the voltage to a safe level. This hardware protection mechanism is independent of software closed-loop control, operating without microcontroller response, and complements the proactive synchronous control in both time and mechanism dimensions, significantly improving the device's safety and fault tolerance under high-voltage impact environments.

[0195] Finally, this invention possesses long-term adaptive capability. Existing series IGBT solutions, once parameter settings are complete, experience a gradual deterioration in voltage equalization due to device aging and environmental temperature changes, failing to automatically track and compensate for delay drift. This invention, through a closed-loop iterative mechanism comprised of steps 101 to 105, utilizes a voltage detection circuit unit and a detection isolation optocoupler to provide real-time feedback on the actual operating time difference of each IGBT stage after each load-bearing closing operation. A sliding window strategy is employed to incorporate the latest measured data into the historical sample pool and replace the oldest data. Before the next closing operation, the average fixed delay is automatically recalculated, data dispersion is evaluated, and compensation parameters are updated. This allows the system to continuously track and compensate for delay changes introduced by factors such as temperature drift, optocoupler CTR attenuation, and IGBT threshold voltage drift throughout its service life. This adaptive closed-loop correction mechanism ensures the long-term operational stability of the device, eliminating the need for periodic manual calibration and significantly reducing maintenance costs and engineering application complexity.

[0196] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0197] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between apparatuses or units through some interfaces, and may be electrical, mechanical, or other forms.

[0198] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-voltage electronic switching device, characterized in that, This includes a multi-stage series IGBT switch module consisting of a microcontroller and multiple IGBT switch modules connected in series. Each of the IGBT switching modules includes a trigger isolation optocoupler, a trigger circuit unit, an IGBT transistor, a voltage detection circuit unit, and a detection isolation optocoupler; One end of the trigger isolation optocoupler is connected to the microcontroller; The other end of the trigger isolation optocoupler is connected to one end of the trigger circuit; The other end of the trigger circuit is connected to the gate of the IGBT transistor; The input terminal of the voltage detection circuit unit is connected in parallel with the IGBT transistor; The output terminal of the voltage detection circuit unit is connected to one end of the detection isolation optocoupler; The other end of the detection isolation optocoupler is connected to the microcontroller.

2. The high-voltage electronic switching device according to claim 1, characterized in that, Each of the IGBT switching modules also includes an isolated independent power supply; The trigger isolation optocoupler, the trigger circuit unit, the IGBT transistor, the voltage detection circuit unit, and the detection isolation optocoupler are all connected to the isolated independent power supply.

3. The high-voltage electronic switching device according to claim 1, characterized in that, The trigger isolation optocoupler includes a trigger isolation transmitting optocoupler and a trigger isolation receiving optocoupler; The input terminal of the trigger isolation emitter optocoupler is connected to the microcontroller; The output terminal of the trigger-isolated transmitting optocoupler is connected to the input terminal of the trigger-isolated receiving optocoupler; The output terminal of the trigger isolation receiver optocoupler is connected to one end of the trigger circuit.

4. The high-voltage electronic switching device according to claim 1, characterized in that, The detection isolation optical coupler includes a detection isolation transmitting optical coupler and a detection isolation receiving optical coupler; The output terminal of the voltage detection circuit unit is connected to the input terminal of the detection isolation emission optocoupler; The output terminal of the detection isolation transmitting optocoupler is connected to the input terminal of the detection isolation receiving optocoupler; The output of the detection isolation receiving optocoupler is connected to the microcontroller.

5. The high-voltage electronic switching device according to any one of claims 1-4, characterized in that, Each of the IGBT switching modules also includes a surge arrester; The surge arrester is connected in parallel with the IGBT tube.

6. A control method applied to the high-voltage electronic switching device according to any one of claims 1-5, characterized in that, include: Control each IGBT switching module to perform multiple no-load closing tests to obtain the corresponding actual closing time difference data; The average fixed delay corresponding to each IGBT switching module is calculated using the actual closing time difference data; Discreteness assessment is performed on the actual closing time difference data described above; When the discreteness evaluation result is qualified, the channel compensation amount corresponding to each IGBT switching module is determined by the average fixed time delay. Based on the compensation amount of each channel, perform a load-bearing closing operation on each IGBT switching module.

7. The control method according to claim 6, characterized in that, The aforementioned multiple no-load closing tests specifically refer to: One of the multiple IGBT switching modules is pre-set as the reference IGBT tube; Under no-load conditions, trigger pulse electrical signals are simultaneously sent to multiple IGBT switching modules; The trigger isolation optocoupler controls the trigger pulse electrical signal to be converted into a trigger pulse optical signal, which then passes through the isolation strip and is restored to a trigger pulse electrical signal and sent to the trigger circuit unit. The control trigger circuit unit amplifies the power of the restored trigger pulse electrical signal to drive the IGBT to conduct. The control voltage detection circuit unit captures the falling edge jump signal of the IGBT in real time and sends it to the detection isolation optocoupler; The control detection isolation optocoupler converts the falling edge jump signal into an optical signal that passes through the isolation strip, and then restores it to a falling edge jump signal; Edge capture is performed on the restored falling edge jump signal to record the actual arrival time of the falling edge of each IGBT transistor. Using the actual arrival time of the voltage drop edge of the reference stage IGBT in each closing test as the reference time, the actual arrival time of each stage IGBT is subtracted from the reference time to obtain the actual closing time difference under a single no-load closing test. By integrating the actual closing time differences under all no-load closing tests, the actual closing time difference data corresponding to each IGBT switch module is obtained.

8. The control method according to claim 6, characterized in that, When the discreteness evaluation result is qualified, the channel compensation amount corresponding to each IGBT switching module is determined using the average fixed delay, including: When the discreteness evaluation result is qualified, the maximum value is selected from all the average fixed delays as the maximum average fixed delay. Subtract each of the average fixed delays from the maximum average fixed delay to obtain the channel compensation amount corresponding to each IGBT switching module; The channel compensation amount is the advance trigger time corresponding to each IGBT switching module relative to the maximum average fixed delay.

9. The control method according to claim 6, characterized in that, When the discreteness evaluation result is qualified, determining the channel compensation amount corresponding to each IGBT switching module using the average fixed delay further includes: When the discreteness evaluation result is qualified, the theoretical reference trigger time of the reference-level IGBT is obtained; Subtract each of the average fixed delays from the theoretical benchmark trigger times to obtain the channel compensation amount corresponding to each IGBT switching module. The channel compensation amount is the absolute trigger time value of each IGBT switching module relative to the theoretical reference trigger time.

10. The control method according to any one of claims 6-9, characterized in that, The discreteness evaluation of each of the actual closing time difference data includes: Calculate the standard deviation of each of the actual closing time difference data; If all the standard deviations are less than the preset acceptable threshold, the dispersion assessment result is deemed acceptable. If any of the standard deviations is not less than the preset acceptable threshold, the dispersion assessment result is determined to be unacceptable.

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