Series-connected thyristor grouping driving device

Abstract

The utility model belongs to motor detection technical field relates to a series connection thyristor grouping drive arrangement, including m one after another series connection's thyristor, the magnetic core of n current transformers all windings o same secondary winding, m, n and o are all positive integers, and m is n's o times, the starting end electric connection current -limiting resistance R1 one end of each secondary winding, current -limiting resistance R1 other end respectively electric connection thyristor's gate and gate resistance R2 one end, gate resistance R2 other end respectively electric connection thyristor's cathode and secondary winding's end, single primary cable one after another passes through the magnetic core center hole of n current transformers, the anode and cathode of each thyristor are connected in parallel with voltage -sharing resistance R3 and pressure sensitive resistance MOV, and resistance R4 and capacitor C1 are connected in series and are connected in parallel with pressure sensitive resistance MOV. The utility model has realized nanosecond level synchronous drive, has built the simplified and reliable system architecture, has strengthened insulation design and anti -interference ability.

Description

Technical Field

[0001] This utility model belongs to the field of motor testing technology, specifically relating to a series thyristor grouping drive device. Background Technology

[0002] High-voltage pulse inter-turn insulation testing is a crucial step in evaluating the reliability and safety of motors. Its core principle involves applying a high-voltage pulse to the motor windings and analyzing the decaying oscillation waveform to determine the insulation condition. With the continuous increase in motor voltage levels, test pulse voltages can reach tens of thousands of volts or more. The withstand voltage capability of a single thyristor is no longer sufficient, and multi-thyristor series technology has become the mainstream solution for implementing high-voltage pulse switching. However, the series thyristor architecture places extremely high demands on trigger synchronization accuracy; nanosecond-level deviations can lead to dynamic voltage equalization failure, causing cascading breakdowns of devices. Furthermore, insulation strength and electromagnetic compatibility under high-voltage pulse conditions are also core challenges in drive circuit design.

[0003] Based on a review of publicly available academic papers and patent documents, the existing technologies for series thyristors mainly focus on the following three types of driving schemes, and their evolution and core technical features are compared as follows: (1) Independent pulse transformer drive scheme. This scheme equips each series thyristor with an independent pulse transformer, and the primary windings of all transformers are connected in series and driven by a common pulse source. Xuji Electric's patent CN202210708457.2 shows an improved transformer drive scheme, which optimizes the quality of the drive waveform through a full-bridge conversion unit and a sampling unit, attempting to reduce the synchronization error caused by the discreteness of the magnetic core parameters. However, this scheme still faces the following problems: First, the difference between the magnetic core saturation characteristics and the distributed capacitance of the windings will cause inconsistent transmission delays in each drive path (typical error >100ns); second, the increase in the number of transformers directly leads to a large system size and high cost, and the excessively long primary series circuit will introduce significant parasitic inductance, limiting the rise rate of the drive pulse.

[0004] (2) Fiber Optic Isolation and High-Level Energy Harvesting Drive Scheme. This scheme uses fiber optic transmission of trigger signals to achieve synchronization and obtains driving energy from both ends of the thyristor through a high-level energy harvesting circuit. The China Academy of Engineering Physics proposed a driving scheme for voltage-controlled thyristors (MCTs) in "High Power Laser and Particle Beams" (February 2025). This design uses fiber optic isolation to solve the synchronization problem and achieves energy self-sufficiency through a high-level energy harvesting circuit. Although fiber optic transmission has certain advantages in signal synchronization accuracy (error can be controlled within 50-100ns), its system complexity is high, and the energy supply of the high-level energy harvesting circuit is unstable under transient conditions of pulse discharge, which may lead to drive failure. In addition, the cost of fiber optic modules and their reliability in strong electromagnetic environments remain obstacles to engineering applications.

[0005] (3) Planar Coupled Inductor Drive Scheme. This is a recently emerging technological approach. The China Academy of Engineering Physics proposed a cascaded drive circuit based on a planar air-core coupled inductor in its paper. This scheme uses a push-pull circuit to supply power to the planar coupled inductor, utilizing the inductor's energy storage to transfer drive energy, thus achieving miniaturization and cascading capability of the drive circuit. Its advantage lies in omitting the complex isolation power supply module and simplifying the system structure. However, the air-core coupler has a low coupling coefficient, resulting in limited energy transfer efficiency, and the consistency of the output waveform is difficult to guarantee when multiple stages are cascaded, limiting its application in high-voltage and high-power scenarios. A performance comparison analysis of existing schemes is shown in Table 1 below.

[0006] Table 1: Performance Comparison Analysis of Existing Solutions Triggering synchronization error >100 ns 50-100 ns No clear report System complexity High (numerous magnetic cores) Medium to high (complex fiber alignment, requiring isolated power supply) Medium (no isolation power supply required, can be cascaded) Energy supply methods Shared pulse source High-level energy extraction Low-voltage power supply + inductor energy storage cost Medium and high high middle Development trend Structural optimization, waveform control Integration improves energy harvesting reliability Miniaturization improves coupling efficiency Comprehensive analysis reveals the following common technical defects in existing technologies, providing a clear direction for innovation in this invention: ① The synchronization bottleneck remains unresolved. Whether it's the parameter dispersion in the transformer scheme or the transmission jitter in the fiber optic scheme, the synchronization accuracy is insufficient to meet the stringent nanosecond-level synchronization requirements of high-voltage testing above 10kV. Insufficient synchronization accuracy leads to dynamic voltage equalization failure, dispersed conduction timing of series thyristors, and subsequent conduction devices subjected to excessive voltage stress, resulting in avalanche breakdown. ② The system complexity and cost remain high. The structure, where the number of components is proportional to the number of thyristors, causes the system size, cost, and failure rate to increase dramatically with increasing voltage levels. The increased number of connection nodes leads to an exponential increase in the probability of failure. ③ Traditional drive units use ordinary insulation materials and processes (such as enameled wire + ordinary impregnation), with limited insulation strength between windings (typical value <1kV AC), insufficient insulation and anti-interference capabilities, and are prone to partial discharge and insulation aging under the action of high voltage pulse rapid dv / dt. Traditional drive units are prone to false triggering under the strong electromagnetic interference generated by high voltage pulses, and their insulation design (such as ordinary transformers and fiber optic connectors) is difficult to withstand potential differences of several kV for a long time, significantly increasing the risk of device thermal breakdown. Summary of the Invention

[0007] To address the technical deficiencies in synchronization, reliability, and insulation adaptability of existing high-voltage series thyristor drive devices, this invention provides a novel series thyristor group drive device. The technical solution adopted by this invention is as follows: A series thyristor grouping drive device includes m thyristors connected in series, and o identical secondary windings wound on the magnetic cores of n current transformers, where m, n, and o are all positive integers, and m is o times n. The starting end of each secondary winding is electrically connected to one end of a current-limiting resistor R1, the other end of the current-limiting resistor R1 is electrically connected to the gate of the thyristor and one end of the gate resistor R2, and the other end of the gate resistor R2 is electrically connected to the cathode of the thyristor and the end of the secondary winding, respectively. A single primary cable passes through the central hole of the magnetic core of the n current transformers in sequence.

[0008] Preferably, the anode and cathode of each thyristor are connected in parallel with the equalizing resistor R3 and the varistor MOV, and the resistor R4 and the capacitor C1 are connected in series and then connected in parallel with the varistor MOV.

[0009] Preferably, the primary cable is made of silicone-insulated high-voltage wire, and the primary cable passes directly through the center of the magnetic core of each current transformer in a straight line, maintaining a straight extension between the magnetic cores of each current transformer.

[0010] Preferably, the magnetic core of the current transformer is prepared by vacuum potting process, and the secondary winding of the current transformer uses triple-insulated wire.

[0011] The beneficial effects of this utility model are: (1) Achieve nanosecond-level high-precision synchronous drive. A synchronous triggering mechanism based on a "single-wire series core" magnetic circuit structure is provided to eliminate transmission path differences from a physical perspective. Through the design of consistent magnetic circuit parameters, the synchronization error is controlled within 50ns, ensuring dynamic voltage balance of the series thyristors and avoiding overvoltage breakdown.

[0012] (2) Construct a simplified and reliable system architecture. Establish a “group-driven” architecture to break the binding relationship between the number of drive units and power devices, reduce the number of current transformer cores for driving thyristors, reduce system complexity by 75%, improve system MTBF (mean time between failures) through architectural innovation, and reduce total life cycle cost.

[0013] (3) Strengthen insulation design and anti-interference capability. The current transformer core adopts three-layer insulation wire and vacuum potting process to improve the insulation strength of the drive unit to >2kV AC; design a stable local energy transfer mechanism to avoid the instability of high-level energy extraction; enhance immunity to high dv / dt and electromagnetic interference from both circuit and structural aspects through optimized gate resistor network and simplified collinear magnetic circuit design. Attached Figure Description

[0014] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the structure of the series thyristor grouping drive device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the driving circuit and protection circuit of the thyristor according to an embodiment of the present invention. Detailed Implementation

[0015] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are some embodiments of this utility model, but not all embodiments.

[0016] This utility model embodiment provides a series thyristor grouping drive device, which adopts an innovative grouping drive architecture. Its core lies in achieving electrical synchronization through a "single-wire series core" physical structure, such as... Figure 1 As shown, the system includes m thyristors (SCR1, ..., SCRm) and n current transformers (TR1, ..., TRn), where m is three times n. The m thyristors are connected in series, and every three thyristors form a group electrically connected to one current transformer. Each current transformer contains three identical secondary windings, each connected to the gate-cathode of a thyristor via an independent drive circuit. A single primary cable passes sequentially through the central hole of the magnetic core of each of the n current transformers.

[0017] Specifically, the starting end of each secondary winding is electrically connected to one end of the current-limiting resistor R1. The other end of the current-limiting resistor R1 is electrically connected to the gate of the thyristor and one end of the gate resistor R2, respectively. The other end of the gate resistor R2 is electrically connected to the cathode of the thyristor and the end of the secondary winding, respectively, forming a complete drive circuit loop. This drive circuit loop design controls the rise rate of the drive pulse through the current-limiting resistor R1, while using the gate resistor R2 to provide a static discharge path, significantly enhancing the system's anti-interference capability and ensuring stable and reliable operation under high-voltage pulse environment.

[0018] As a further preferred embodiment, to ensure stable system operation under high-voltage conditions, each thyristor is also connected in parallel with a protection circuit. The anode and cathode of the thyristor are connected in parallel with the voltage equalization resistor R3 and the varistor MOV. The resistor R4 and capacitor C1 are connected in series and then in parallel with the varistor MOV. The voltage equalization resistor R3 provides static voltage equalization protection; the varistor MOV provides overvoltage protection; and the resistor R4 and capacitor C1 form a damping network to ensure dynamic voltage equalization.

[0019] In this embodiment of the invention, the output terminal of the pulse signal source is electrically connected to the beginning of the primary cable. The primary cable passes through the core center hole of the current transformer TRn, ..., the core center hole of the current transformer TR1 in sequence, and the end of the primary cable finally returns to the ground terminal of the pulse signal source, forming a complete excitation circuit.

[0020] The m thyristors are connected in a strict series configuration: the anode of thyristor 1 is connected to the positive terminal of the energy storage capacitor as the high-voltage input terminal, the cathode of thyristor 1 is connected to the anode of thyristor 2, and so on, forming a complete series link. The cathode of thyristor m is connected to one end of the winding of the motor under test, and the other end of the winding of the motor under test is connected to the negative terminal of the energy storage capacitor, together forming the main discharge circuit.

[0021] The workflow is executed in the following order: a pulse signal source generates a trigger pulse with a nanosecond rising edge; the pulse current passes synchronously through n high permeability magnetic cores via a single primary cable; three identical secondary windings wound on each magnetic core synchronously induce a drive voltage; the drive voltage directly drives the corresponding thyristor through an optimized resistor network; multiple thyristors achieve synchronous conduction in a very short time.

[0022] The key innovation of this architecture lies in breaking the traditional 1:1 drive ratio and adopting a 1:3 group drive mode, which greatly simplifies the system structure while ensuring synchronization performance.

[0023] The primary cable uses silicone-insulated high-voltage wire and comprises an integral cable transmission section one, a cable bend section, and a cable transmission section two. Cable transmission section one passes directly through the center of each magnetic core, maintaining a straight extension between the magnetic cores of each current transformer, effectively avoiding magnetic circuit asymmetry caused by bending. The cable bend section is close to the current transformer TRn. Cable transmission section one and cable section two are arranged in parallel. The magnetic circuit design of this invention adopts a unique collinear layout, ensuring that the centers of the magnetic cores of multiple current transformers are precisely aligned on the same straight line, forming a simplified elliptical magnetic circuit.

[0024] The core advantages of the magnetic circuit design are reflected in three aspects: ① All magnetic cores share the same magnetic circuit, fundamentally eliminating the path differences in traditional distributed layouts; ② The same magnetic circuit environment ensures that the magnetic reluctance and coupling coefficient of each magnetic core are highly consistent; ③ The straight primary cable minimizes the loop inductance, providing ideal conditions for high-speed pulse transmission.

[0025] The secondary winding of the current transformer uses triple-insulated wire, and the magnetic core of the current transformer is fabricated using a vacuum potting process, thereby increasing the insulation strength of the drive unit to >2kV AC and preventing the high voltage of the thyristor cathode from interfering with the circuit of the primary coil. The use of triple-insulated wire and vacuum potting process in the secondary winding ensures insulation reliability under high-voltage environments.

[0026] The main innovations of the series thyristor grouping drive device provided in this embodiment of the utility model include: (1) Group drive architecture: The series thyristors are divided into multiple groups, and each group shares a current transformer core. Multiple (e.g., 3) secondary windings with the same inductance value are wound on the core, which drive multiple thyristors in the group respectively, breaking the traditional one-to-one drive mode.

[0027] (2) Synchronous triggering circuit of single-wire series magnetic core: All driving magnetic cores are connected in series by the same wire to form a primary excitation circuit that ensures absolute synchronization.

[0028] (3) Simplified collinear magnetic circuit structure: The magnetic ring centers of multiple current transformers are arranged on the same straight line, so that the primary cable naturally forms a simplified elliptical magnetic circuit after passing through all the magnetic rings, so as to achieve uniform magnetic resistance and minimize parasitic parameters.

[0029] (4) Optimized gate resistor network: The secondary winding is connected through a series network of “small resistance current limiting resistor -> thyristor gate -> large resistance gate resistor -> thyristor cathode”.

[0030] Finally, the performance of this drive device was experimentally verified through the construction and testing of a prototype. In a system with 12 thyristors connected in series, a high-voltage pulse with a peak voltage of 10kV was successfully achieved, and the voltage rise time of this pulse was less than 100ns. The significance of this experimental result is twofold: ① It directly proves the synchronization performance. The voltage can rise from 0 to 10kV within 100ns, fully demonstrating that all 12 series-connected thyristors are driven and turned on almost synchronously in an extremely short time. Any significant trigger delay will cause the pulse rise edge to be elongated or to form a step. ② It verifies the driving capability. This result proves that the drive device of this invention can provide a sufficiently strong (high di / dt) driving current, enabling the thyristors to respond quickly and jointly support the rapid establishment of the high-voltage pulse.

[0031] The series thyristor grouping drive device provided in this embodiment of the invention has advantages such as high synchronization accuracy, simplified structure, optimized cost, and high reliability. It effectively solves key technical problems such as synchronous triggering of series thyristors, system complexity, and insulation reliability in high-voltage pulse systems. Specifically, it is reflected in: (1) The collaborative design of "single-wire series core" and "collinear magnetic ring" eliminates the difference in driving path from the circuit perspective and ensures the consistency of magnetic circuit and minimum parasitic parameters from the physical structure perspective. The advantage is that it achieves extremely high synchronization accuracy. Experiments have verified that it can generate a high voltage pulse of 10kV / 100ns when driving 12 series thyristors, which fundamentally eliminates the thyristor overvoltage breakdown caused by asynchronous triggering.

[0032] (2) By adopting a “one-to-three” grouping mode, the number of magnetic cores, connecting cables and circuit complexity of the system are greatly reduced. The advantages are: while achieving the above-mentioned high performance, the drive device has an extremely simplified structure, significantly reduced manufacturing costs, compact size and high overall reliability.

[0033] (3) The device employs a gate resistor network that combines strong triggering and anti-interference capabilities, along with a customized high-insulation / encapsulated current transformer. This allows the device to provide a high di / dt drive current instantaneously to support the rapid establishment of high-voltage pulses, while effectively suppressing noise coupling from the high-voltage oscillation circuit. Furthermore, the drive module itself has extremely high insulation strength, eliminating the risk of breakdown. The advantages are: near-zero false triggering and high stability operation are achieved in the harsh electromagnetic environment of high-voltage pulse testing, and the system's lifespan and safety are fundamentally guaranteed.

[0034] In this embodiment of the utility model, all technical features not described in detail are existing technologies or conventional technical means, and will not be repeated here.

[0035] Finally, it should be noted that the above embodiments are merely specific implementations of this utility model, used to illustrate the technical solution of this utility model, and not to limit it. The protection scope of this utility model is not limited thereto. Those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the technical scope disclosed in this utility model; and these modifications, changes, 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 this utility model, and should all be covered within the protection scope of this utility model.

Claims

1. A series thyristor grouping drive device, comprising m thyristors connected in series sequentially, characterized in that, Each of the n current transformers has o identical secondary windings wound on its core. m, n, and o are all positive integers, and m is o times n. The starting end of each secondary winding is electrically connected to one end of a current-limiting resistor R1. The other end of the current-limiting resistor R1 is electrically connected to the gate of the thyristor and one end of the gate resistor R2, respectively. The other end of the gate resistor R2 is electrically connected to the cathode of the thyristor and the end of the secondary winding, respectively. A single primary cable passes through the center hole of the core of each of the n current transformers in sequence.

2. The series thyristor grouping drive device according to claim 1, characterized in that, The anode and cathode of each thyristor are connected in parallel with the equalizing resistor R3 and the varistor MOV, and the resistor R4 and capacitor C1 are connected in series and then in parallel with the varistor MOV.

3. The series thyristor grouping drive device according to claim 2, characterized in that, The primary cable uses silicone-insulated high-voltage wire. The primary cable passes directly through the center of the magnetic core of each current transformer in a straight line, and the primary cable extends in a straight line between the magnetic cores of each current transformer.

4. The series thyristor grouping drive device according to claim 2, characterized in that, The magnetic core of the current transformer is prepared by vacuum potting process, and the secondary winding of the current transformer uses triple-insulated wire.

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