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А high-voltage multicellular power supply with energy transfer through a current loop and current transformers is considered. The power source (static-electricity converter) consists of an inverter that generates a current with a preset magnitude in a current loop, which consists of a cable segment, and current transformers, the primary winding of which is represented by a current loop, as well as controlled rectifier cells. Such a decision makes it possible to provide a reliable isolation level between the input and output circuits of the source with a rather simple design of the device. Owing to the use of the same type of rectifier cells in the structure, one can provide a simple scaling of the source according to the output voltage level, as well as a simple setup and repair of the device. The principle of operation has been considered, and the choice of engineering solutions for the main components of the device has been justified. A system for stabilizing rectifier cell output voltage has been investigated as an automatic control system with pulse-phase control. The frequency characteristics of this system for two modes of energy transfer to the load are obtained, the modes are compared, and the most promising one is determined. A mockup of a 10-kV power supply has been manufactured and tested. The results of testing have confirmed the correctness of the calculations and the efficiency of the proposed approach. [ABSTRACT FROM AUTHOR]

Objective. The article presents the results of experimental studies on the effect of a high-potential electrostatic field on the combustion of liquid fuel. Method. Experimental studies were carried out on the developed laboratory installation, which makes it possible to ensure the combustion of liquid fuel in a high-potential electrostatic field with the possibility of changing the polarity. The change in the polarity of the applied voltage to the electrode system of the experimental setup led to an increase in the fuel burning rate in the first case, and to its attenuation in the second.Result. In this paper, studies have been carried out proving the effect of an electrostatic field on the burning rate and reducing the content of harmful components (soot and carbon monoxide) in fuel combustion purges. Based on the values of the fuel burning rate obtained as a result of the experiments, graphic dependences were constructed on the applied voltage, on which the areas of linear and non-linear changes in the combustion parameters were identified.Conclusion. The results of the research carried out can be used to create new highly efficient burners for liquid fuel boilers. The effect of reducing the burning rate can be used to create fire safety devices that block the spread of flame during a fire.

The energy intensity of the output circuit of a high-voltage pulse source for a gas-discharge load is determined by the totality of energies accumulated in its reactive elements in operating or transient modes. During breakdowns in the output circuit of high-voltage power supplies, the accumulated energy can be released uncontrollably and lead to element failures or technological defects. The relationship between the magnitude of the output voltage ripple, the load resistance, the parameters of the inductive-capacitive output filter, the power of the power source and the frequency of its conversion has been established. Analytical expressions are obtained that make it possible to calculate the parameters of the output filter of a high-voltage powerful power supply based on the allowable energy that can accumulate in the output filter while providing allowable voltage ripples at the output of the converter. It has been established that the lower the attenuation coefficient of transient processes, the more energy must be accumulated in the filter elements to ensure the required quality of the output energy. On a calculated example of a power supply with a voltage of 30 kV, a power of 450 kW, a conversion frequency of 20 kHz and output ripples of less than 1%, it is shown that for implementation without oscillatory transients with significant changes in load current, the energy intensity of the output filter can exceed 1 J/kW. With an increase in the equivalent conversion frequency, this indicator can be significantly reduced. [ABSTRACT FROM AUTHOR]

Widely applied in medical, industrial, and military fields, the high-voltage power supply based on LCC resonant converter (LCC) is ought to establish tens kilovolts of output voltage within milliseconds according to many standards. And any overshoot during this start-up process is not allowed because of the issue or even deadly consequence it may lead. Traditional linear control schemes are powerless to fulfill these two conflicting requirements, especially for the LCC with nonlinear gain characteristics. In this paper, a multi-segment fuzzy control is proposed to tackle this problem. Firstly, the nonlinear gain curve of LCC is piecewise linearized based on its large-signal model, and the control requirements for different segments are determined. Then the control parameters for each part are selected by an off-line fuzzy algorithm. The allowed minimum frequency during the start-up is also piecewise linearized so that the gain ability of LCC is utilized. Finally, the proposed control scheme is verified with an 80kW/150kV X-ray power supply. A low-cost controller is used to implement the start-up control scheme since the control parameters can be pre-calculated and stored in the controller. Compared with the commonly used linear PI control, the non-overshoot start-up time with the proposed control scheme is reduced by more than 60%.

This article deals with a vacuum-arc ion source, which generates high-intensity beams of metal ions. The power supply system largely determines the ion source parameters such as accelerating voltage, average current, and pulse current densities of the ion beam. This article proposes the power supply system for the vacuum-arc ion source intended for the generation of pulses with the length up to $2000~\mu \text{s}$ at an accelerating voltage up to 50 kV. At the frequency of 50 Hz, the average ion current can reach 50 mA due to long pulses. This article considers the main design solutions for the generation of long pulses. A comparison is given to the novel power supply system based on insulated-gate bipolar transistors (IGBTs) and the earlier thyristor power supply. [ABSTRACT FROM AUTHOR]

This article puts forward a high repetition rate and high-voltage resonant pulse generator for plasma-assisted milling. This circuit uses only one semiconductor switch with an antiparallel diode and works in the resonant mode with the help of a resonant inductor, a resonant capacitor, and a pulse transformer to generate high-voltage pulses. An equivalent circuit of the proposed topology considering parasitic elements is established. Based on the equivalent circuit, the working principle of the pulse generator is analyzed in detail. In order to verify the theoretical analysis and circuit operation, a laboratory prototype with a 150-V dc input is implemented. The pulse repetition rate can be adjusted from 5.32 to 18.90 kHz, and the peak output voltage correspondingly varies between 8.84 and 11.7 kV. The pulse generator is used to drive a dielectric barrier discharge plasma-assisted milling chamber. Experimental results show that the pulse generator can work stably. [ABSTRACT FROM AUTHOR]

This paper presents an improved three-phase PWM rectifier with predicted current space voltage-vector pulse width modulation technology. The designed rectifier can realize controllable soft start, and has high power factor and wide voltage regulation．A new over current protection circuit is designed，which has fast response speed and can meet repetitive start requirement of high voltage supply application．Simulation and test results show that the improved PWM rectifier can achieve controllable soft start and the error in steady state is less than 2%，the recovery time is less than 0.5 s after a sudden change of the load，the power factor is more than 95%．

In this article, a new high-voltage and high-frequency power supply for ozone generation is introduced. This circuit uses a single switch and works in the resonant mode with the help of transformer magnetizing and leakage inductances (without adding a distinct resonant inductor), a separate resonant capacitor, and a step-up transformer to generate high voltage output. The simulation results demonstrate that with a 250-V dc input, a 7.9-kV pulse with 1.66 μs pulse-width is generated at the output. A hardware prototype with 250-V dc input and 7.3-kV output pulse is developed. The pulse repetition frequency can go up to 15 kHz, and the efficiency of 84% is achieved. The simulation, experimental, and microbiological test results are presented to validate the proposed converter and its operating principle. [ABSTRACT FROM AUTHOR]

In order to realize the 200 keV negative-ion-based neutral beam injector (N-NBI) prototype of China Fusion Engineering Test Reactor, an acceleration grid power supply (AGPS) is under development. Adopting a single stage inverter type topology, the AGPS is rated at 200 kV/25A for 3600 s. Here, the paper presents a distributed control system based on PCI extensions for instrumentation (PXI) and field programmable gate array (FPGA) technology, which can fulfill the high requirements in terms of the control strategy, malfunction protection, integration with the upper control system and real-time monitoring, highlighting the operation sequence both in normal and abnormal scenarios. In addition, a 10 kV/6A AGPS prototype has been realized to verify the control system. The distributed control system can respond to the interlock signal from the upper controller within 2 μs while disabling the inverter within 20 μs in case of an abnormal current or voltage output status. [ABSTRACT FROM AUTHOR]

Featured Application: Power supply construction for dielectric barrier or corona discharge, atmospheric pressure plasma reactors. Non-thermal plasma reactors offer numerous advantages and are used in a wide variety of applications. Exemplary fields of use include exhaust gas or water quality improvement, surface processing, agriculture, or medical processes. Two of the most popular discharge chamber constructions are dielectric barrier discharge (DBD) and pulsed corona discharge (PCD, barrierless) plasma reactors. Various power supply constructions are presented in the literature with varying complexity and operating principles. A simple, power electronic, pulsed power supply construction is presented in this work, implementing resonant power switch operation, modern silicon carbide (SiC) power semiconductors and a Tesla coil-like transformer design. The power supply construction is immune to short circuits in the reactor and can be used for both types of reactor constructions. The principles of operation, simulation results, and prototype test verifications are presented with main power supply characteristics. [ABSTRACT FROM AUTHOR]

Magnetic pulse compressors, based on magnetic switches, are considered as competitive candidates for high-voltage pulse generation. It is generally believed that the lack of operating-parameter tunability of these devices is currently one of the crucial factors limiting their applications. In this paper, an adjustable high-power magnetic pulse compressor, which is deemed as the key component of a power supply system, is investigated theoretically and experimentally. Dominant parameters of the compressor, including the compression ratio, the saturation time, and the peak voltage, can be regulated, which is beneficial for widening the application areas of power supply systems. Specifically, the prepulse of the magnetic pulse compressor is studied as one of the key parameters. A two-stage magnetic pulse compressor was then setup and when the charging time of the primary source was alternated between 19 and 25 μs, pulses with rise-time of 1 μs were achieved with good repeatability. This in turn verified the tunable capacity of the device. When applied in a solid-state high-voltage pulse generator, the pulse compressor successfully enabled the generation of intense electron-beam with peak power over 5 GW, peak voltage of 380 kV, pulse width over 170 ns, and repetitive rate of 20 Hz. The device has been successfully used for research on plasma science and for driving the sources of high-power microwaves where the requirements on the device often vary substantially. In the latter application, based on the high reliability of the solid-state pulse generator, optical diagnosis has been conducted of the plasma expansion characteristics of the magnetically insulated coaxial diodes cathode, in order to analysis the mechanism of the pulse shortening phenomenon. Experimental results show reasonable agreements with the analyses. [ABSTRACT FROM AUTHOR]

The Korea Superconducting Tokamak Advanced Research (KSTAR) is planned to be installed with an electron cyclotron (EC) system to achieve a 6 MW radiofrequency (RF) output by 2024, and this installation is currently in progress. At present, five gyrotrons are installed for the EC system of the KSTAR. Among these, four EC systems are installed with 105/140 GHz dual-frequency gyrotrons, each generating 950 kW of RF power at 140 GHz and 800 kW of RF power at 105 GHz. Moreover, an EC system additionally installed in 2022 is a 170 GHz single-frequency gyrotron, and it generates 1 MW of RF power. The high-voltage power supply (HVPS) and the EC integrated control system (ECICS) were developed in 2019 to obtain a more stable and efficient EC system. Several useful functions were added to the newly developed ECICS for efficient EC system operation. Real-time control operations and shot retrigger are now possible with the application of this integrated control system. In addition, a function to automatically save and recall shot information was added and is essential for reducing operator errors. The new HVPS was designed in the pulse step modulation (PSM) topology, and a crowbar system was applied as a double protection device to protect the gyrotron. Instead of the heavy and bulky oil-cooling type high-voltage switch, a light and low-maintenance natural air-cooling type commercial switch was applied. The newly developed HVPS and ECICS were applied in the 2020 and 2021 KSTAR campaigns. Unfortunately, serious problems such as noise and timing issues were discovered during the two-year KSTAR campaign. Therefore, the second upgrade of the HVPS and ECICS was conducted in 2022 to realize a more stable and accurate EC system. The core part of the ECICS was developed anew, and the structure of the control system was significantly upgraded. In addition, the control method of the HVPS PSM module was newly developed. Moreover, the communication method between the ECICS and the controller of the HVPS was upgraded. In this paper, the upgraded HVPS and ECICS are explained in detail, and a discussion on the experimental results of the upgraded system for the next KSTAR campaign is also presented. [ABSTRACT FROM AUTHOR]

Non-thermal plasma reactors offer numerous advantages and are used in a wide variety of applications. Exemplary fields of use include exhaust gas or water quality improvement, surface processing, agriculture, or medical processes. Two of the most popular discharge chamber constructions are dielectric barrier discharge (DBD) and pulsed corona discharge (PCD, barrierless) plasma reactors. Various power supply constructions are presented in the literature with varying complexity and operating principles. A simple, power electronic, pulsed power supply construction is presented in this work, implementing resonant power switch operation, modern silicon carbide (SiC) power semiconductors and a Tesla coil-like transformer design. The power supply construction is immune to short circuits in the reactor and can be used for both types of reactor constructions. The principles of operation, simulation results, and prototype test verifications are presented with main power supply characteristics.

A DC −1 MV insulating transformer has been developed for the power supply of the neutral beam injector ( NBI) at ITER (International Thermonuclear Experimental Reactor) . A DC long-pulse −1 MV insulation structure between the primary and secondary windings, considering potential variation in the insulator for DC long pulse, has been designed. Simultaneous development of a compound bushing, which consists of an AC 500 kV condenser bushing inside a cylindrical fiber-reinforced plastic tube, has been carried out. The DC −1 MV insulation design has been verified by high-voltage insulation tests of AC 50 Hz 1300 kV peak for 1 min, DC −1200 kV for 1 h, and a long-duration test of DC −1060 kV for 5 h. The results showed that the insulating transformer satisfies the power supply requirements for the ITER NBI. Copyright © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

In view of shortcomings such as poor reliability, high error rate existed in current leakage protection system of underground high-voltage power grid，a design scheme of leakage protection system of underground power grid based on ZigBee wireless sensor network was put forward. The system adopts CC2530 as core and uses improved RSSI location algorithm to locate fault position，which realizes remote fault location, and reduces error rate. The test results show that performance of the system is stable, and meets requirements of leakage protection of underground power grid.

This paper presents a new driving method for a sulfur plasma lamp in low-power applications. The newly developed magnetron power supply (MPS) is a series-resonance type with a full-bridge topology controlled by the phase shift to track the beam current of the magnetron. To drive the sulfur plasma lamp optimally, the MPS should: 1) provide peak power above a discharge condition to excite the sulfur plasma lamp, and 2) allow average power control of the light dimmer while satisfying condition 1. The newly developed driving method uses the burst mode, which enables both peak and average power controls to satisfy these conditions. Furthermore, a magnetizing current offset balancer is developed; it guarantees zero-voltage switching of all field-effect transistors, although the MPS operates in the burst mode. Thus, the proposed method provides easy lighting and relighting under optimized conditions with high efficiency. The power of the MPS delivered by the proposed method reached 1.6 kW with variable average power of 200 ∼ 400 W by adjusting burst-on time proportionally. Experimental results proved the feasibility of the proposed driving method. [ABSTRACT FROM PUBLISHER]

Capillary electrophoresis (CE) systems have undergone extensive development for spaceflight applications. A flight-compatible high voltage power supply and the necessary voltage isolation for other energized components can be large contributors to both the volume and mass of a CE system, especially if typical high voltage levels of 25-30 kV are used. Here, we took advantage of our custom CE hardware to perform a trade study for simultaneous optimization of capillary length, high voltage level, and separation time, without sacrificing method performance. A capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C 4 D) method recently developed by our group to target inorganic cations and amino acids relevant to astrobiology was used as a test case. The results indicate that a 50 cm long capillary with 15 kV applied voltage (half of that used in the original method) can be used to achieve measurement goals while minimizing instrument size., (© 2022 Wiley-VCH GmbH. California Institute of Technology. Government sponsorship acknowledged.)

This paper describes the design and implementation of a three-phase resonant converter with low ripple and high control accuracy. Based on a three-phase LCC-type resonant converter—which has advantages of low ripple, high-efficiency, and high-power density compared with a single-phase converter—a high-voltage power supply with low ripple (<0.1%) was designed. In addition to the general merits of an LCC-type resonant converter operating at continuous conduction mode—including soft switching, low conduction loss, and current source characteristics—the proposed scheme uses only one phase under a light-load condition by having different leg designs of the gate drive circuit and snubber parameters. This allows the design to overcome the operational constraints of the general LCC-type resonant converter. The distinctive design of the three-phase converter structure provides high efficiency and low ripple not only during rated operation, but also under light-load conditions. In order to analyze the high performance of the proposed scheme from no load to rated load, a PSPICE simulation was carried out. Comparison results with a conventional LCC-type resonant converter based on a single-phase structure are analyzed from the viewpoints of output ripple, losses, and operable load range. Using the proposed converter, a 20-kV, 20-kW high-voltage dc power supply design and implementation was presented with a superior gate drive circuit. Finally, the superiority of the proposed converter was verified through a simulation and experimental results. It was experimentally confirmed that the developed power supply achieves high performance in terms of efficiency (98%), operable load range (0.5–20 kV), and low ripple (0.05%), with a high power density. [ABSTRACT FROM PUBLISHER]

A switching circuit with a high conversion ratio is proposed in this paper, due to the fact that it is difficult for the basic line frequency voltage-multiplying rectifier to keep its output voltage constant when the load varies, and its windings and volume of the set-up transformer are large. The proposed circuit operated in discontinuous conduction mode, and its operation was divided into three subintervals. The steady-state gain function for output voltage verse input voltage was derivate by virtual capacitor method and average modeling. The switching circuit combined merits of the voltage-multiplier with flyback converters. It was very suitable for low-power high-voltage power applications where small size and high conversion ratio were needed. The operations and prominent characteristics of the converter were described. A laboratory prototype was built based on the analysis. The effectiveness of proposed approach is verified by experimental results. [ABSTRACT FROM AUTHOR]

Although research on electrostatic precipitators (ESPs) has studied and analyzed all the technical aspects of this device, their cost is, nowadays, the major constraint for manufacturers and users. Therefore, medical waste incinerators of hospitals in Algeria, as well as municipal waste incinerators, operate, in most cases, without flue gas filtration system due to the high costs that requires the installation of a cleaning system. This constraint is reflected in the Maghreb and African countries. The objective of this paper is to show that it is possible to build up a cost-efficient ESP, including a high-voltage power supply made up of a static converter and a step-up ferrite transformer. A home-made “wire-plate”-type half-scale prototype ESP was designed and served to optimize the filtration efficiency according to the interelectrode distance and to determine the optimum voltage to be applied without risk of breakdown. [ABSTRACT FROM PUBLISHER]

It is well known that ozone concentration depends on air/oxygen input flow rate and power consumed by the ozone chamber. For every chamber, there exists a unique optimum flow rate that results in maximum ozone concentration. If the flow rate is increased (beyond) or decreased (below) from this optimum value, the ozone concentration drops. This paper proposes a technique whereby the concentration can be maintained even if the flow rate increases. The idea is to connect n number of ozone chambers in parallel, with each chamber designed to operate at its optimum point. Aside from delivering high ozone concentration at high flow rate, the proposed system requires only one power supply to drive all these (multiple) chambers simultaneously. In addition, due to its modularity, the system is very flexible, i.e., the number of chambers can be added or removed as demanded by the (output) ozone requirements. This paper outlines the chamber design using mica as dielectric and the determination of its parameters. To verify the concept, three chambers are connected in parallel and driven by a single transformer-less LCL resonant power supply. Moreover, a closed-loop feedback controller is implemented to ensure that the voltage gain remains at the designated value even if the number of chambers is changed or there is a variation in the components. It is shown that the flow rate can be increased linearly with the number of chambers while maintaining a constant ozone concentration. [ABSTRACT FROM PUBLISHER]

In high-voltage systems such as in pulse power, commonly used semiconductor devices cannot be applied to the generation part of high-voltage pulse. However, unlike semiconductor, the magnetic switch cannot control its own ON and OFF operation. Moreover, with the magnetic switch the system efficiency goes down with load variation, and arcs caused by saturation of the energy in reactor have a negative effect on the whole system. This letter presents the way to effectively control the magnetic switch applied to high-voltage pulse power supplies such as plasma generators. The efficiency of the system is optimized by automatically controlling the magnetic switch based on the load variation. Then, the energy the load requires is supplied to the system, which leads to the stability of the system. The proposed method is confirmed by experiments on a designed system. [ABSTRACT FROM AUTHOR]

This paper describes the analysis and design of an LCL resonant power supply for ozone generation. The main advantage of the proposed topology is the absence of high-voltage transformer; the high voltage gain is achievable by means of double-resonance phenomena. Furthermore, the bandwidth is wider than the ordinary LC and its phase difference is constant over specific frequency range; as a result, an open-loop operation can be implemented. The complete analysis and design procedure of the power supply is presented. The design procedure is verified by implementing the power supply to drive a dielectric barrier discharge prototype ozone chamber. The hardware results are found to be in close agreement with simulation and thus justify the validity of the design procedures. The proposed circuit is suitable for portable ozone power supply fed by low-voltage source such as battery or photovoltaic module. [ABSTRACT FROM AUTHOR]

This paper describes the design and analysis of a 42-kW (14 kV, 3 A) high-voltage power supply for a 30-kW industrial magnetron drive. The design is based on a series resonant converter in discontinuous conduction mode (DCM) to take advantage of both the superior arc protection stemming from the current source characteristics and the high power density owing to the use of parasitic elements such as the leakage inductance in the high-voltage transformer. The detailed design procedure for the resonant tank and high-voltage transformer with respect to the input and output specifications is described on the basis of a simplified analysis of the DCM series resonant converter. Special considerations for designing high-power high-voltage power supplies are provided, such as series stacking of diodes for a voltage doubling rectifier and insulation between each winding of the high-voltage transformer. In addition, a comparative study using theoretical equations, simulation, and experimental results was carried out. This study yielded the output voltage and current characteristics at different switching frequencies and verified the advantages of this topology, such as arc protection without an additional protection circuit and high efficiency due to zero-current or zero-voltage switching. Moreover, the parallel operation of two converters with phase shifted gating signal is proposed to reduce the output current ripple and increase power capability for higher power magnetron drive. Additionally, the design considerations of two auxiliary power supplies (a filament power supply: 15 V, 150 A and a magnet power supply: 50 V, 5 A) are also provided and optimized for effective driving industrial magnetron. Finally, the developed power supply was tested with a 30-kW industrial magnetron, and the results prove the reliability and robustness of the proposed scheme. [ABSTRACT FROM PUBLISHER]

This paper presents the steady-state analysis of a fixed-frequency phase-shift LCLC resonant converter with a capacitive output filter which is a very attractive topology for high-voltage applications. A conventional modeling procedure cannot thoroughly describe the converter behavior particularly at the load side. A comprehensive converter analysis is presented, and the obtained analytical expressions precisely describe the converter behavior. This paper shows that the range of zero-voltage-switching operation would extend significantly since the variations of the phase shift can be reduced by this topology. Therefore, high efficiency is achievable for a wide range of operation. This paper also provides some converter practical description for high-voltage implementation. The experimental results obtained from a 1.8-kW prototype verify the theoretical analysis and demonstrate the validity and accuracy of the employed model. [ABSTRACT FROM AUTHOR]

A miniaturized, scalable, and rad-hard high-voltage module is demonstrated as a “proof-of-concept.” The module is suitable for space applications. The design uses a commercial process that combines 0.25-\mum complementary metal-oxide semiconductor (CMOS) transistors with a high-voltage lateral double-diffused metal-oxide-semiconductor (DMOS) device (>600 V). The design was simulated, fabricated, and tested and shows functionality up to 2.5 kV. Several radiation-hardening-by-design (RHBD) techniques were used to improve radiation hardness over 100 krad. [ABSTRACT FROM AUTHOR]

• Upgrade of ECH HVPS (high voltage power supply) system for more stable and efficient long pulse operation in KSTAR • Development of an ECICS (Electron cyclotron integrated control system) applied new functions and structures for safe and stable EC system operation • Successful experimentation of upgraded EC system in 2020 KSTAR campaign • Successfully maintained H-mode plasma during over 70 seconds at 100 million degrees using the new EC system. • Due to the successful experimental results, the HVPS and ECICS systems are planned to be applied to all six EC systems. Korea Superconducting Tokamak Advanced Research (KSTAR) is planning to install an auxiliary heating device comprising six electron cyclotron (EC) systems with a total of 6 MW of radiofrequency (RF) output. Two EC systems were operated in the 2019 KSTAR campaign. To compensate the shortcomings identified during the operation of the previous two systems, the power supply was upgraded and a new integrated control system was developed. A power supply is a device that affects the RF beam quality generated by the gyrotron of an EC system and ensures efficient operation. Features such as real-time operation, a crowbar system, and a redundancy module were added to the upgraded power supply. An integrated control system is an important device that protects a gyrotron and supports stable operation. The overall structure of the integrated control system was changed to enable real-time operation, and functions such as retrigger and shot-information were added. In the 2020 KSTAR campaign, a new EC system including the upgraded power supply and the new integrated control system was added, and a total of three EC systems were operated. The new EC system was successfully employed at KSTAR. In this paper, we explain in detail the upgraded power supply and the new integrated control system and show and discuss the results of their application to the 2020 KSTAR campaign. [ABSTRACT FROM AUTHOR]

High-voltage DC power supplies are used in several applications, including X-ray, plasma, electrostatic precipitator, and capacitor charging. However, such a high-voltage power supply has problems, such as a decrease in reliability, owing to an increase in output ripple voltage, and a decrease in power density, owing to an increase in volume. Therefore, this study proposes a method for improving the power density of a parallel resonant converter using the parasitic capacitor of the secondary side of the transformer. Due to the fact that high-voltage power supplies have many turns on the secondary side, a significant number of parasitic capacitors are generated. In addition, in the case of a parallel resonant converter, because the transformer and the primary resonant capacitor are connected in parallel, the parasitic capacitor component generated on the secondary side of the transformer can be equalized and used. A parallel cap-less resonant converter structure developed using the parasitic components of such transformers is proposed. Primary side and secondary side equivalent model analyses are conducted in order to derive new equations and gain waveforms. Finally, the validity of the proposed structure is verified experimentally. [ABSTRACT FROM AUTHOR]

• 1, A new control method of the CFETR N-NBI accelerator grid power supply-conversion system topology is put forward. • 2, The proposed control method is based on master-slave architecture, the bottom slave is applied for rectifier and inverter, the top master is applied for AGPS. • 3, The control model of 3L-NPC rectifier and 5L-NPC/H inverterapplied for AGPS are developed. • 4, The adjustable DC-link voltage and phase-shifted carrier-pulse-width modulation are discussed, simulation results are performed that validate the new control method. The China Fusion Engineering Test Reactor (CFETR) uses a negative-ion neutral beam injection (N-NBI) system that requires a powerful acceleration grid power supply (AGPS). The AGPS is rated at -1000 kV/80 A and feeds one injector. AGPS-conversion system, which uses a three-level neutral-point-clamped active front-end rectifier as well as a five-level neutral-point-clamped / cascaded H-bridge inverter, was investigated in the reference design. Because the control problem of the conversion system is crucial for the AGPS, a well-designed control method can improve the steady-state performance during operation substantially. To achieve the full potential of the proposed design and meet the challenging demands of the CFETR N-NBI system, a new control method is proposed and investigated in this paper. Considering the requirement to provide a wide range output voltage, the new control method provides an adjustable DC-link voltage for the rectifier with unity power factor and a suitable modulation factor for the inverter, while maintaining a low ripple voltage of output voltage. The steady performance of the AGPS is successfully improved using phase-shifted carrier-pulse-width modulation. Simulation results are performed that validate the new control method. [ABSTRACT FROM AUTHOR]

• A new approach to the CFETR N-NBI accelerator grid power supply-conversion system topology is put forward. • The parameters and operation principle of the proposed conversion system are designed and analyzed. • CFETR AGPS simulation process is carried on to verify that the newly-design scheme is feasible. The acceleration grid power supply (AGPS) is developed to provide accelerator power for China Fusion Experimental Rector (CFETR) Negative-ion Neutral Beam Injection (N-NBI) system. The rated output parameters of this AGPS are -1000kV/80A/80MW. The preliminary design of the AGPS is proposed in this paper. To improve the steady-state and dynamic performance of the AGPS, a new CFETR AGPS conversion system (AGPS-CS) based on three-level neutral point clamped (3L-NPC) rectifier and five-level neutral-point-clamped/cascaded H-bridge (5L-NPC/H) inverter is presented. The parameters of AGPS-CS are obtained theoretically, and simulations are used to verify its operational performance and show the effectiveness of the proposed topology. Results indicate that the proposed design provides good input-output features and can meet the requirements of the CFETR N-NBI system. This solution can also be used as a reference for the design of large-power high-voltage power supply. [ABSTRACT FROM AUTHOR]

In pulsed power system, mechanical characteristic means the structure of the plasma reactor, and impedance matching between the pulse generator and the plasma reactor means the electrical characteristics. It is a very important issue in the industry because impedance matching is closely related to the efficiency and reliability of the pulsed power system. In this paper, the design and implementation for improving the energy density of the wire-plate plasma reactor are presented. The system configuration, impedance characteristics and structures of the plasma reactor are described, and the output characteristic of the plasma reactor according to the structure of the wires and plates is analyzed. The plasma reactor model is realized on the simulation tool, and the simulation results are compared with the experiment data. Based on the theoretical analysis and the simulated model, impedance matching between the wire-plate plasma reactor and the pulsed power generator can be more fully achieved. [ABSTRACT FROM AUTHOR]