A compact coaxial structure ultra-high voltage pulse transformer

Abstract

The application relates to a compact coaxial structure super-high-multiple-voltage direct-current pulse converter, belonging to the technical field, which comprises an upper computer control unit, a main control component and a high-voltage source, the main control component contains a low-voltage modulation circuit and a digital control and protection system, the low-voltage modulation circuit integrates a direct-current modulation circuit and a pulse modulation circuit, and generates low-voltage high-frequency pulses and modulation pulses with adjustable amplitude and pulse width respectively; the high-voltage source contains a step-up transformer, a spiral coaxial stacked voltage doubling rectification network, an equipotential shielding cylinder, a high-thermal-conductivity insulation medium filling layer and a pulse trigger source, the spiral coaxial stacked voltage doubling rectification network adopts a spiral coaxial stacked structure in which multiple capacitors and silicon stacks are spirally and coaxially stacked along a circumference, the parasitic capacitances of the multiple capacitors and silicon stacks are symmetrically distributed to the equipotential shielding cylinder, and the structure is self-voltage-equalized. The application has the advantages of small size, self-voltage-equalization, good heat dissipation, excellent electromagnetic compatibility, flexible and adjustable dual-path output and full solid state maintenance-free and the like.

Description

Technical Field

[0001] The high-voltage DC pulse converter involved in this invention belongs to the field of high-voltage DC pulse power supply technology, and in particular relates to a compact coaxial structure ultra-high voltage DC pulse converter. Background Technology

[0002] High-voltage DC pulse converters are widely used in radar, medical equipment, particle accelerators, high-voltage testing and pulse power technology. With the increasing demand for miniaturization of equipment, how to achieve ultra-high voltage output in a limited space while ensuring insulation reliability, heat dissipation efficiency and electromagnetic compatibility has become a technical problem that urgently needs to be solved in this field.

[0003] The existing high-voltage DC pulse sources mainly adopt the following schemes: 1. Planar discrete component voltage multiplier combination scheme: This scheme involves laying out and soldering silicon stacks, capacitors, and voltage equalizing resistors on a PCB or insulating bracket. The withstand voltage requirement is met by increasing the spacing between components and spraying insulating varnish. The pulse output requires an additional modulation stage. The drawbacks of this scheme are: the volume increases approximately proportionally with the output voltage, the electric field is concentrated at the solder joints and small curvature connections, and there is a lack of overall field uniformity measures; the thick insulating layer required for withstand voltage has poor thermal conductivity, and local temperature rise accelerates insulation aging.

[0004] 2. Modular cascaded scheme: Each voltage multiplier unit is independently potted, and the modules are connected in series with high voltage wires or connectors, arranged in a planar or stepped manner. This scheme also has the problem of large size, and the pulse introduction requires additional space. The uneven parasitic parameters lead to dynamic interstage voltage drop imbalance, which requires additional voltage equalization resistor chain compensation, increasing power consumption and the number of components.

[0005] 3. Coaxial stacked design: Voltage multiplier elements are stacked step by step along the central axis, with annular insulating sheets or potting materials between the stages. Although this design improves space utilization to some extent, most of them can only output a single DC, making it difficult to integrate pulse generation components. The edge of the annular electrode and the dielectric interface are still areas of field strength distortion.

[0006] 4. Oil-immersed / gas-filled closed-loop solution: The voltage multiplier module is immersed in insulating oil or filled with high-pressure gas, and the gap is compressed by the high breakdown medium. The disadvantages of this solution are: the sealed cavity volume is large, high-voltage isolation is required for pulse introduction, and the system is complex; liquid and gas-assisted heat dissipation brings sealing and maintenance risks; the thermal expansion coefficients of the potting medium and solid insulation are mismatched, and interface peeling or air gaps are easily generated by cold and hot cycles.

[0007] Furthermore, existing solutions mostly employ analog regulation or low-speed digital management in terms of control, lacking nanosecond-level fault protection and closed-loop real-time regulation capabilities. This makes it difficult to ensure output stability and device safety under extreme operating conditions. Human-machine interaction is usually limited to a simple local panel, which cannot achieve remote real-time monitoring and flexible parameter configuration. Currently, no single converter can simultaneously provide adjustable DC high voltage and adjustable pulse width and amplitude single pulse output, while also ensuring high reliability, ease of manufacturing, high-speed control, and remote intelligent management. Summary of the Invention

[0008] This invention provides a compact coaxial structure ultra-high voltage DC pulse converter, which aims to solve the problems of electric field concentration, heat dissipation, voltage equalization, precise control and rapid protection under multiple outputs in a compact space by using a spiral coaxial stacked layout, equipotential shielding cylinder, high thermal conductivity matching packaging medium, dual-channel modulation integrated design, digital high-speed loop control and remote human-machine interaction.

[0009] The solution to the above-mentioned technical problems of the present invention is as follows: a compact coaxial structure ultra-high voltage DC pulse converter, including a host computer control unit, a main control component and a high voltage source.

[0010] The host computer control unit is used to set operating parameters and monitor the converter status in real time. Through this host computer control unit, operators can remotely set parameters such as DC output voltage, pulse amplitude, pulse width and repetition frequency, and know the equipment operating status in real time, realizing intelligent remote management of the converter, effectively reducing the professional threshold requirements for operators, and improving the safety and convenience of using the converter.

[0011] The main control component includes a low-voltage modulation circuit and a digital control and protection system. The low-voltage modulation circuit includes a DC modulation circuit and a pulse modulation circuit, which respectively generate low-voltage high-frequency pulses and modulation pulses with adjustable amplitude and pulse width. This dual-channel integrated design enables a single device to simultaneously achieve two output modes: DC high voltage and adjustable single pulse, without the need for an external modulation stage, which greatly simplifies the system configuration and broadens the application scenarios of the device.

[0012] The high-voltage source includes a DC step-up transformer, a pulse step-up transformer, a spiral coaxial stacked voltage multiplier rectifier network, an equipotential shielding cylinder, a high thermal conductivity insulating dielectric filling layer, and a pulse triggering source.

[0013] The DC step-up transformer and the pulse step-up transformer receive the low-voltage excitation output from the DC modulation circuit and the pulse modulation circuit respectively and step up the voltage. The two transformers work independently, serving the DC circuit and the pulse circuit respectively, ensuring that the two outputs do not interfere with each other, and providing the required voltage level for subsequent voltage multiplication and pulse modulation.

[0014] The spiral coaxial stacked voltage multiplier rectifier network consists of multiple high-voltage capacitors and high-voltage silicon stacks. Each stage is arranged spirally upward along the circumference in quadrant order. Adjacent stages are interconnected near the axis by low-impedance welding to form a spiral coaxial stacked structure. This spiral coaxial stacked structure enables the components of each stage to be evenly distributed in three-dimensional space, which greatly reduces the axial and radial dimensions of the voltage multiplier network. At the same time, it makes the parasitic capacitance of each stage to the equipotential shielding cylinder tend to be consistent, providing a topological basis for the structure to self-equalize voltage.

[0015] The equipotential shielding cylinder is coaxially sleeved outside the spiral coaxial stacked voltage multiplier rectifier network, forming an equipotential cavity connected to the internal reference potential. The equipotential shielding cylinder works synergistically with the spiral coaxial stacked structure to ensure that the parasitic capacitance of each stage to the equipotential shielding cylinder and the interstage capacitance are symmetrically distributed and approximately equal in size. This achieves self-equalization of voltage under high-frequency pulse conditions, eliminating the need for the voltage equalization resistor chain required in traditional solutions, thus reducing power consumption and circuit complexity. At the same time, the equipotential shielding cylinder also provides electrostatic shielding, blocking the outward coupling of the high-voltage electric field, improving electromagnetic compatibility performance, and reducing output ripple.

[0016] The high thermal conductivity insulating dielectric filling layer is filled between conductors in the high voltage area, between conductors and equipotential shielding cylinders, and within the PCB isolation slots, achieving full filling without gaps. This high thermal conductivity insulating dielectric filling layer not only withstands high voltage and provides an insulation barrier, but also efficiently conducts the heat generated by internal components to the external shell, eliminating the hidden danger of partial discharge that easily occurs in traditional air gaps, while solving the problem of heat dissipation difficulties for high voltage components; its thermal expansion coefficient matches the contact metal and PCB materials, and it does not peel or crack during thermal cycling, ensuring long-term insulation reliability.

[0017] The pulse trigger source is coaxially mounted on the high-voltage lead-out terminal of the final stage of the spiral coaxial stacked voltage multiplier rectifier network. It receives the high-voltage modulated pulse output by the pulse step-up transformer and outputs a high-voltage single pulse superimposed on the DC level after fast switching modulation. The coaxial integration of the pulse trigger source and the voltage multiplier network avoids the distributed parameters and electromagnetic interference problems caused by long high-voltage leads, making the output pulse leading edge steep and the amplitude precisely controllable.

[0018] Furthermore, discharge resistors and silicon stacks are provided in the gaps between the capacitors of each stage of the spiral coaxial stacked voltage multiplier rectifier network and the PCB. The discharge resistors are used to discharge the residual charge of the capacitors after power failure. After the equipment is powered off, the discharge resistors safely discharge the high voltage charge stored in the voltage multiplier capacitors, avoiding the risk of electric shock to operators caused by residual charge and improving the safety of equipment maintenance. At the same time, the discharge resistors do not participate in the voltage equalization under operating conditions, eliminating the impact of their power consumption on system efficiency.

[0019] Furthermore, the PCB has isolation grooves between different potential areas. These isolation grooves provide a flow channel for the high thermal conductivity insulating medium during the potting process. The opening of these isolation grooves ensures that the insulating medium can completely fill all gaps and eliminate internal air bubbles during potting, making the electric field distribution more uniform. At the same time, it increases the creepage distance along the surface and effectively suppresses surface discharge.

[0020] Furthermore, the equipotential shielding cylinder, together with the grounding isolation plate, forms an electrostatic shielding structure between high and low voltage, cutting off the coupling path of the high-voltage pulse electric field to the low-voltage circuit. This shielding structure effectively suppresses the interference of high-voltage side capacitive coupling on the low-voltage control circuit, ensuring the stability of the control system and reducing output ripple and pulse jitter.

[0021] Furthermore, the primary and secondary windings of the DC step-up transformer and the pulse step-up transformer are wound in sections, and multiple layers of insulation barriers are provided between the primary and secondary windings, between secondary sections, and between the winding and the magnetic core. An equalizing body is installed at the secondary high-voltage output terminal. This sectioned winding and multi-layer insulation barrier design increases the creepage distance and reduces the interlayer field strength, enabling the transformer to reliably withstand high voltage. The equalizing body suppresses electric field concentration and partial discharge at the output terminal, thereby improving the insulation life of the transformer.

[0022] Furthermore, the final stage of the spiral coaxial stacked voltage multiplier rectifier network is connected in series with a current-limiting resistor. This current-limiting resistor is integrated with the equipotential shielding cylinder and the high-voltage lead-out terminal. When the output discharges, the current-limiting resistor limits the transient current and the rate of current rise, protecting the internal power devices and high-voltage structure from overcurrent impacts. At the same time, it suppresses transient overvoltages, ensuring the controllability of the output waveform and the safety of the equipment. Its integrated design with the equipotential shielding cylinder and the lead-out terminal ensures the controllability of the output electric field and avoids the introduction of new field strength distortion points.

[0023] Furthermore, the digital control and protection system includes an independent high-speed ADC sampling unit, a digital controller, a hardware comparator chain, and programmable logic. The independent high-speed ADC sampling unit respectively collects the output voltage, output current, and key node voltage and current signals of the DC channel and pulse channel. The digital controller performs real-time closed-loop adjustment based on the set value and sampling feedback. The hardware comparator chain and programmable logic monitor the sampled signals cycle by cycle, triggering nanosecond-level hardware protection actions when overcurrent, overvoltage, arcing, or pulse parameter exceeding the limit is detected. This digital control and protection system achieves independent and precise control of the two outputs. The hardware-level protection can cut off instantaneous overload within nanoseconds. Together with digital cycle limiting and software status monitoring, it forms a three-layer protection system to ensure the safety of power devices and high-voltage structures under extreme operating conditions.

[0024] Furthermore, the high-voltage side signal is transmitted to the low-voltage control domain via a sampling loop composed of a high-bandwidth isolation operational amplifier. The isolation operational amplifier has high common-mode rejection ratio and low propagation delay characteristics. This high-bandwidth isolation operational amplifier ensures the integrity and fast response capability of the signal during the high- and low-voltage isolation transmission process, enabling the control system to capture the rapid leading edge of the pulse and dynamic disturbances in a timely manner, providing accurate real-time data for high-speed closed-loop regulation and precise protection.

[0025] Furthermore, the host computer control unit is connected to the main control component via a wired communication interface, providing a graphical user interface for remotely setting DC output voltage, pulse amplitude, pulse width, and repetition frequency parameters, and displaying output voltage, current, system temperature, and fault indication information in real time. This host computer control unit enables human-machine isolation operation of the equipment, allowing operators to perform fine adjustments and comprehensive monitoring of the equipment from a safe distance. Multi-level permission management and parameter range restriction functions prevent misoperation and improve the safety of equipment use.

[0026] Furthermore, the converter is an all-solid-state packaged structure that does not rely on oil immersion or gas-filled insulation. This all-solid-state packaged structure eliminates the need for sealed cavities and auxiliary systems required by oil immersion or gas-filled solutions, significantly reducing volume and weight, eliminating leakage risks, and enabling the equipment to adapt to a wide temperature range, vibration and other harsh operating conditions, achieving maintenance-free long-term stable operation.

[0027] The beneficial effects of this invention are as follows: This invention provides a compact coaxial structure ultra-high voltage multiplier DC-DC pulse converter, which has the following advantages: 1. Self-equalizing overall structure simplifies circuit: The spiral symmetrical layout and equipotential shielding cylinder work together to achieve self-equalizing voltage using parasitic capacitance, eliminating the need for an additional equalizing resistor chain. This results in fewer components, lower power consumption, and higher reliability. The discharge resistor is only responsible for discharging residual charge when the power is off and does not participate in voltage equalization under operating conditions.

[0028] 2. The compact package solves the problems of insulation and heat dissipation: the gapless high thermal conductivity medium eliminates the concentration of field strength, allowing high withstand voltage with reduced spacing; the short radial low thermal resistance path conducts heat efficiently, and the heat dissipation capacity is significantly improved while the volume is reduced.

[0029] 3. Dual-channel output with flexible adjustment: Each unit integrates adjustable DC high voltage and adjustable single pulse output, with pulse amplitude and pulse width independently adjustable to meet the needs of multiple application scenarios.

[0030] 4. Uniform electric field, suppressing partial discharge and corona: equalizing body, equipotential shielding, gapless potting and PCB isolation groove eliminate curvature abrupt changes, uniform electric field distribution, no peeling during hot and cold cycles, and long insulation life.

[0031] 5. Good electromagnetic compatibility: The equipotential shielding cylinder and isolation plate cut off the capacitive coupling between high and low voltage, resulting in low output ripple and clean pulse leading edge.

[0032] 6. Nanosecond-level rapid protection: Hardware comparator chain and programmable logic realize cycle-by-cycle monitoring and nanosecond-level protection actions, and the three-layer protection system ensures equipment safety under extreme conditions.

[0033] 7. No oil immersion or gas filling required, good environmental adaptability: All-solid-state packaging eliminates leakage risk, withstands wide temperature range, resists vibration, and requires no maintenance.

[0034] 8. Enables intelligent remote management: The host computer's graphical interface enables remote parameter setting, real-time monitoring, and access control, reducing the operational threshold and improving security.

[0035] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Specific embodiments of the present invention are given in detail below with reference to the accompanying drawings. Attached Figure Description

[0036] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a system block diagram of a compact coaxial structure ultra-high voltage multiplier DC-DC pulse converter provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the outer cylinder structure of the high-voltage source in a compact coaxial ultra-high voltage multiplier DC pulse converter according to an embodiment of the present invention; Figure 3 This is a partial structural detail of the spiral coaxial stacked voltage multiplier rectifier network in a compact coaxial ultra-high voltage multiplier DC pulse converter provided in an embodiment of the present invention. Detailed Implementation

[0037] The following is in conjunction with the appendix Figure 1-3 The principles and features of the present invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. The invention is described more specifically in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0039] Example 1: The overall structure of the converter is as follows Figure 1 As shown, this embodiment provides a compact coaxial structure ultra-high voltage DC pulse converter, which includes three main components: a host computer control unit, a main control component, and a high voltage source. The three components are connected through a communication bus and a high-low voltage isolation interface to work together to complete adjustable DC high voltage and adjustable single-pulse high voltage output.

[0040] The host computer control unit is based on a human-machine interface (HMI) and runs on an embedded terminal. It connects to the main control component via a wired communication interface. Operators can remotely set parameters such as DC output voltage, pulse amplitude, pulse width, and repetition frequency through a graphical user interface, and monitor output voltage, current, system temperature, and fault indications in real time. The host computer control unit also has multi-level operation permissions and parameter range restriction functions to prevent misoperation; it is equipped with an independent remote emergency stop function, which can cut off the high voltage output with one click in an emergency.

[0041] The main control unit is located on the low-voltage side and includes a low-voltage modulation circuit and a digital control and protection system. The low-voltage modulation circuit includes a DC modulation circuit and a pulse modulation circuit. The DC modulation circuit converts the DC input into a low-voltage high-frequency pulse. The switching devices alternately turn on and off to obtain a high-frequency square wave voltage on the primary side of the DC step-up transformer, which is matched with the subsequent voltage multiplier network. The pulse modulation circuit generates modulation pulses with adjustable amplitude and pulse width to drive the primary side of the pulse step-up transformer. The primary sides of the two channels share a common ground and are uniformly controlled by the digital controller.

[0042] The digital control and protection system uses a digital chip as the main controller and runs a real-time loop control algorithm. The DC channel and pulse channel are each equipped with an independent high-speed ADC sampling unit to collect output voltage, output current and key node voltage and current signals, respectively. The digital controller performs real-time closed-loop adjustment based on the set value and sampling feedback. The DC channel stabilizes the high-voltage DC output through frequency modulation and pulse width modulation. The pulse channel precisely controls the pulse amplitude, pulse width and repetition characteristics. All high-voltage side signals are transmitted to the low-voltage control domain through a sampling loop composed of high-bandwidth isolation operational amplifiers. The isolation operational amplifiers are selected with high common-mode rejection ratio and low propagation delay to ensure signal integrity and response speed. The sampling rate is optimized to capture the fast leading edge of the pulse and dynamic disturbances. Before entering the digital controller, the sampled data undergoes anti-aliasing filtering and digital preprocessing to extract peak value, average value and transient characteristics.

[0043] The digital controller incorporates a hardware comparator chain and programmable logic to monitor the sampled signal cycle by cycle. When overcurrent, overvoltage, arcing, or pulse parameter exceeding limits is detected, hardware protection is triggered within nanoseconds, forcibly shutting down the drive pulse and reporting the fault status. The protection mechanism consists of three layers: hardware nanosecond-level rapid protection to cut off instantaneous overload; digital layer to limit current and voltage peak values ​​in each modulation cycle; and software layer to continuously monitor temperature and system health, smoothly reducing power or safely shutting down when necessary. The control algorithm adaptively adjusts loop parameters based on load characteristics and converter status to optimize dynamic response and steady-state ripple. The system state before and after the fault is recorded in non-volatile memory for easy post-fault analysis and maintenance.

[0044] The high-frequency pulses and modulation pulses output by the low-voltage modulation circuit are stepped up by two step-up transformers. The transformers are located inside the high-voltage source, and high-low voltage isolation and energy and signal transmission are achieved through magnetic circuit coupling.

[0045] Example 2: Spiral coaxial stacked voltage multiplier rectifier network as follows Figure 3 As shown, the high-voltage source is equipped with a spiral coaxial stacked voltage multiplier rectifier network. This network consists of multiple high-voltage capacitors and high-voltage silicon stacks. Each stage contains paired capacitors and silicon stacks. The number of stages of the voltage multiplier network is determined according to the target output voltage.

[0046] When viewed from above along the axial direction, each stage is arranged spirally upward along the circumference in the order of the first to the fourth quadrant. Specifically, the first stage is located in the first quadrant of the circumference, the second stage is located in the second quadrant and its axial height increases by one stage, the third stage is located in the third quadrant and its axial height increases by another stage, and the fourth stage is located in the fourth quadrant and its axial height increases by another stage. This cycle repeats to form a spirally ascending topology. Adjacent stages are interconnected near the axis by low-impedance welding to form a spiral coaxial stacked structure. This spiral coaxial stacked structure allows the components of each stage to be evenly distributed in three-dimensional space, significantly compressing the axial and radial dimensions of the voltage multiplier network.

[0047] A discharge resistor and silicon stack are placed in the gap between the capacitor and the PCB. The discharge resistor is a high-resistance resistor, which can quickly discharge the residual charge of the capacitor after power is cut off to ensure operational safety. Isolation slots are opened in each high and low potential area on the PCB. The width and depth of the isolation slots are determined according to the working voltage level. The isolation slots provide a flow channel for the high thermal conductivity insulating medium in the potting process to ensure that the insulating medium can completely fill all gaps during potting.

[0048] Example 3: Integrated structure of equipotential shielding cylinder as follows Figure 2 As shown, the voltage multiplier network is encased in a metal equipotential shielding cylinder, which is connected to an internal reference potential (grounded or intermediate potential) to form an equipotential cavity. The inner diameter of the equipotential shielding cylinder is determined based on the outer diameter of the voltage multiplier network to ensure a uniform thickness of the filling layer.

[0049] The spiral coaxial layout makes the parasitic capacitance of each level of the equipotential shielding cylinder symmetrical and similar in size. Under high-frequency pulse conditions, these parasitic capacitances can play a dynamic voltage equalization role without the need for an additional parallel voltage equalization resistor chain. The equipotential shielding cylinder and the grounding isolation plate together form an electrostatic shielding structure between high and low voltage, cutting off the coupling path of the high-voltage pulse electric field to the low-voltage circuit. The equipotential shielding cylinder is provided with high-voltage lead-out holes and low-voltage inlet holes, and a voltage equalization structure is set at the hole openings to prevent electric field concentration.

[0050] Example 4: High thermal conductivity insulating dielectric filling process High thermal conductivity insulating medium is filled between conductors in the high voltage zone and between conductors and equipotential shielding cylinder. In this embodiment, a packaging material with both excellent electrical insulation and high thermal conductivity is selected. This material can withstand high voltage and efficiently conduct internal heat to the outer shell. Moreover, its coefficient of thermal expansion must match the contact metal and PCB materials to prevent cracking.

[0051] The filling process is as follows: First, the assembled voltage multiplier network and equipotential shielding cylinder are placed in a vacuum potting device and a vacuum is drawn to remove internal gases. Then, a high thermal conductivity insulating medium is injected from the bottom, using the isolation grooves on the PCB as flow channels to ensure that the medium can completely fill all gaps. After potting, curing is carried out according to the predetermined curing conditions. The cured medium is tightly bonded to the electrodes, equipotential shielding cylinder, and PCB isolation groove structure without any gaps, eliminating electric field distortion at sharp corners such as solder joints and bends. It allows for a reduction in insulation spacing while maintaining high withstand voltage. The heat generated by the internal components is efficiently conducted to the equipotential shielding cylinder along a short radial path and dissipated. The thermal expansion coefficient of the medium matches the materials of the electrodes and equipotential shielding cylinder, and it does not peel or crack during thermal cycling, ensuring long-term reliable insulation.

[0052] Example 5: The final stage of the voltage multiplier rectifier is connected to the high-voltage lead-out terminal to output DC high voltage. A pulse trigger source is coaxially installed on the lead-out terminal. The pulse trigger source receives the high-voltage modulation pulse sent by the pulse step-up transformer. After being modulated by a fast switch, a high-voltage single pulse superimposed on the DC level is generated at the output terminal. The high-voltage component of the pulse trigger source is also integrated with the equipotential shielding cylinder and potting medium to meet the requirements of pressure resistance and heat dissipation.

[0053] A current-limiting resistor is connected in series in the output circuit. The current-limiting resistor is used to limit the discharge transient current and the current rise rate, protect the power devices and high-voltage structure from overcurrent impact, and suppress transient overvoltage. The current-limiting resistor is integrated with the equipotential shield and the high-voltage lead-out terminal to ensure the controllability of the output electric field and avoid introducing new field strength distortion points.

[0054] Example 6: Dual-output working mode; The converter in this embodiment can operate in the following two modes: DC output mode: The host computer control unit sets the DC output voltage value, the DC modulation circuit of the main control component generates low-voltage high-frequency pulses, which are boosted by the DC step-up transformer and sent to the spiral coaxial stacked voltage multiplier rectifier network to output a stable DC high voltage. The digital controller stabilizes the output by combining frequency modulation and pulse width modulation.

[0055] DC superimposed pulse output mode: Based on DC output, the host computer control unit sets the pulse amplitude, pulse width and repetition frequency. The pulse modulation circuit of the main control component generates the corresponding modulation pulse, which is boosted by the pulse boost transformer and drives the fast switch of the pulse trigger source. A high voltage single pulse output is superimposed on the DC level. The two channels work together without interfering with each other.

[0056] The current-limiting resistor connected in series in the output circuit limits the discharge current to a safe range when the output discharges (such as when the load breaks down or sparks), thus protecting the internal components.

[0057] Example 7: All-solid-state packaging and environmental adaptability; The converter in this embodiment adopts an all-solid-state encapsulation structure, which does not rely on oil immersion or gas-filled insulation. All high-voltage components are integrated in the shielded encapsulation system, with only the low-voltage input interface, high-voltage output interface and communication interface left on the outside. The equipotential shielding cylinder also serves as the encapsulation shell, and both ends are sealed with insulating end caps.

[0058] The all-solid-state packaging eliminates the risk of leakage and can adapt to harsh conditions such as wide temperature range and vibration, achieving long-term stable operation without maintenance.

[0059] Example 8: Implementation Results; The converter in this embodiment adopts a spiral coaxial stacked layout, with each stage of components uniformly distributed in three-dimensional space, which significantly reduces the axial and radial dimensions of the voltage multiplier network, realizing the miniaturization of the converter. Through the synergistic effect of the equipotential shielding cylinder and the spiral coaxial stacked structure, the parasitic capacitance of each stage to the equipotential shielding cylinder and the interstage capacitance are symmetrically distributed and similar in size, achieving structural self-voltage equalization under high-frequency pulse conditions, eliminating the need for an additional voltage equalization resistor chain, reducing power consumption and circuit complexity. Through the gapless full filling of the high thermal conductivity insulating medium, the risk of electric field distortion and partial discharge is eliminated, while achieving efficient heat dissipation and ensuring long-term insulation reliability. By integrating DC modulation and pulse modulation dual channels on the low-voltage side, a single converter can simultaneously achieve two output modes: DC high voltage and adjustable single pulse. Through the three-layer protection system of digital control and protection system, nanosecond-level fast protection and precise closed-loop control are achieved. Through all-solid-state packaging, the converter does not require oil immersion or gas filling, eliminating the need for sealed cavities and auxiliary systems, eliminating the risk of leakage, and adapting to harsh operating conditions.

[0060] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Content not described in detail in this specification is prior art known to those skilled in the art.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Those skilled in the art can readily implement the present invention based on the accompanying drawings and the above description. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the present invention, utilizing the disclosed technical content, are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A compact coaxial structure ultra-high voltage DC-DC pulse converter, comprising a host computer control unit, a main control component, and a high voltage source, characterized in that, The host computer control unit is used to set operating parameters and monitor the converter status in real time. The main control component includes a low-voltage modulation circuit and a digital control and protection system. The low-voltage modulation circuit includes a DC modulation circuit and a pulse modulation circuit, which are used to generate low-voltage high-frequency pulses and modulation pulses with adjustable amplitude and pulse width, respectively. The high-voltage source includes a DC step-up transformer, a pulse step-up transformer, a spiral coaxial stacked voltage multiplier rectifier network, an equipotential shielding cylinder, a high thermal conductivity insulating dielectric filling layer, and a pulse triggering source. The DC step-up transformer and the pulse step-up transformer respectively receive the low-voltage excitation output from the DC modulation circuit and the pulse modulation circuit and step up the voltage. The spiral coaxial stacked voltage multiplier rectifier network consists of multiple high-voltage capacitors and high-voltage silicon stacks. Each stage is arranged spirally upward along the circumference in quadrant order. Adjacent stages are interconnected near the axis by low-impedance welding to form a spiral coaxial stacked structure. The equipotential shielding cylinder is coaxially sleeved outside the spiral coaxial stacked voltage multiplier rectifier network and connected to the internal reference potential to form an equipotential cavity. The high thermal conductivity insulating dielectric filling layer is filled between conductors in the high voltage area and between the conductor and the equipotential shielding cylinder; The converter has an all-solid-state package structure and does not rely on oil immersion or gas insulation.

2. The compact coaxial structure ultra-high voltage DC-DC pulse converter according to claim 1, characterized in that, The pulse trigger source is coaxially integrated with the spiral coaxial stacked voltage multiplier rectifier network and is located at its final high-voltage output terminal. It receives the high-voltage modulation pulse output by the pulse step-up transformer and outputs a high-voltage single pulse superimposed on the DC level after fast switching modulation. The final stage of the spiral coaxial stacked voltage multiplier rectifier network is connected in series with a current-limiting resistor, which is integrated with the equipotential shielding cylinder and the high-voltage lead-out terminal.

3. The compact coaxial structure ultra-high voltage DC-DC pulse converter according to claim 1, characterized in that, The gaps between the capacitors of each stage of the spiral coaxial stacked voltage multiplier rectifier network and the PCB are provided with discharge resistors and silicon stacks. The discharge resistors are used to discharge the residual charge of the capacitors after power is cut off and do not participate in the dynamic voltage equalization when the voltage multiplier network is working.

4. The compact coaxial structure ultra-high voltage DC-DC pulse converter according to claim 3, characterized in that, The PCB has isolation grooves between different potential regions. These isolation grooves provide a flow channel for the high thermal conductivity insulating medium during the potting process to eliminate internal voids. The thermal expansion coefficient of the high thermal conductivity insulating medium filling layer is matched with the materials of the electrodes, PCB, and equipotential shielding cylinder.

5. The compact coaxial structure ultra-high voltage DC-DC pulse converter according to claim 1, characterized in that, The equipotential shielding cylinder, together with the grounding isolation plate, forms an electrostatic shielding structure between high and low voltage circuits, which is used to cut off the coupling path of the high-voltage pulse electric field to the low-voltage circuit.

6. The compact coaxial structure ultra-high voltage DC-DC pulse converter according to claim 1, characterized in that, The primary and secondary windings of the DC step-up transformer and the pulse step-up transformer are wound in sections, and multiple layers of insulation barriers are provided between the primary and secondary windings, between the secondary winding sections, and between the winding and the magnetic core. An equalizing body is installed at the secondary high-voltage output terminal.

7. The compact coaxial structure ultra-high voltage DC-DC pulse converter according to claim 1, characterized in that, The digital control and protection system includes an independent high-speed ADC sampling unit, a digital controller, a hardware comparator chain, and programmable logic. The independent high-speed ADC sampling unit respectively acquires the output voltage, output current and key node voltage and current signals of the DC modulation circuit and the pulse modulation circuit; The digital controller performs real-time closed-loop adjustment based on the set value and sampled feedback; The hardware comparator chain and programmable logic monitor the sampled signal cycle by cycle, and trigger nanosecond-level hardware protection actions when overcurrent, overvoltage, arcing, or pulse parameter exceeding the limit is detected.

8. The compact coaxial structure ultra-high voltage DC-DC pulse converter according to claim 1, characterized in that, The high-voltage side signal of the high-voltage source is transmitted to the low-voltage control domain via a sampling loop composed of a high-bandwidth isolation operational amplifier, which has high common-mode rejection ratio and low propagation delay characteristics.

9. The compact coaxial structure ultra-high voltage DC-DC pulse converter according to claim 1, characterized in that, The host computer control unit is connected to the main control component via a wired communication interface, providing a graphical user interface for remotely setting DC output voltage, pulse amplitude, pulse width and repetition frequency parameters, and displaying output voltage, current, system temperature and fault indication information in real time.

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