Aug 2026· Review of Scientific Instruments· Vol 97 8· 0 citations· 17 references
Medicine
Abstract
All-solid-state Marx generators have shown broad application prospects in fields such as dielectric barrier discharge, biomedical engineering, and environmental treatment. When pursuing nanosecond-scale fast-front pulses, the extremely high voltage change rate (dv/dt) can readily induce Miller false turn-on in switching devices. Meanwhile, conventional isolated driving schemes with robust noise immunity typically rely on bulky independent power supplies, which severely limit the development of highly compact pulsed power systems. To address these challenges, this paper proposes a compact composite magnetic isolation drive circuit that eliminates the need for an independent high-voltage isolated power supply. The proposed topology integrates a passive negative-voltage bootstrap network with an active Miller clamp (AMC) branch. Through the establishment of a transient mathematical model and ablation experiments, the synergistic immunity mechanism of the composite drive is revealed: the steady-state negative bias generated by bootstrapping, together with the low-impedance discharge path provided by the AMC, physically blocks the path through which high-frequency displacement currents could otherwise elevate the gate potential. Quantitative parasitic parameter scanning shows that even with a severe gate stray inductance of 50 nH, the proposed scheme maintains the transient gate voltage within the safe operating area of the device. Based on the above investigation, a 20-stage SSMG experimental prototype was developed. Experimental results demonstrate that the system operates stably under a wide load range (2-20 kΩ) at a repetition frequency of 1 kHz, successfully outputting fast-front high-voltage pulse sequences with an amplitude of 20 kV and a rise time of 22.9 ns.
Power electronics converters that are high-performance and efficient are essential to the production of power from renewable sources. Nevertheless, low-voltage generation poses a serious challenge for electric vehicle applications utilizing renewable power sources like solar, fuel cells, etc. For this reason, high-gain (HG) DC-DC converters with low duty cycle variation are seen to be crucial for the use of EVs powered by renewable energy. This research presents a novel HG converter using the switched-inductor and voltage lifting approach. The suggested circuit uses a single switch to achieve an impressive voltage gain of approximately 8 times at 60% duty ratio while putting minimal voltage stress on the components. In both continuous and discontinuous conduction modes, the suggested circuits steady-state analysis is described. A design approach with an emphasis on components is examined, and it is compared extensively with state-of-the-art topologies. The performance of the proposed high-gain DC-DC converter with the nonlinear gain compensated PI voltage control (NGC-PI) based control strategy is evaluated under various operating conditions. A prototype of a 200W converter is tested in the lab with an input voltage of 24 V DC. The real-time performance and efficacy of the proposed converter are in line with analytical assumptions. The proposed converter achieves a peak analytical efficiency of 94.46%, while the experimentally measured efficiency remains in the range of 93-95% under different load and power conditions.
Madhav Kumar, K. Panda, Ritula Thakur et al.· IEEE Access· 0 citations
The high-energy fragment separator (HFRS) at the high-intensity heavy-ion accelerator facility (HIAF) employs 11 superferric superconducting dipole magnets to deflect heavy-ion beams. Operating at a design current of 210 A and storing 370 kJ of magnetic energy, each magnet requires a dedicated DC power supply capable of providing highly stable excitation current and fast quench protection. This article presents a complete power supply system for these magnets, with particular emphasis on a modular quench protection module (QPM) and an FPGA-based centralized controller. The QPM adopts a redundant full-bridge IGBT architecture in a compact 4U form factor. Upon receiving magnet quench trigger signals via a fiber optic interface, it completes IGBT turn-off and energy extraction circuit engagement within a microsecond-scale response time, thereby enabling fast and reliable magnet protection. The FPGA main controller incorporates a masking communication mechanism, which provides centralized management, independent control, and real-time diagnosis of magnet quench and module faults for distributed power units. Through a serial device server, the centralized controller simultaneously monitors the operating status and configures parameters for up to six power supply units over RS-485 links. Experimental results confirm that the power supply achieves a current stability of $\pm 1 \times 10^{-4}$ . Under simulated magnet quench conditions, the protection system successfully transfers the stored energy to an external dump resistor, validating the reliability and effectiveness of the proposed scheme. The system provides a scalable protection solution for the HFRS superconducting dipole magnet array.
Fangfang Zhu, Kaiming Wu, Huajian Zhang et al.· IEEE Transactions on Nuclear...· 0 citations
This paper presents a modular, highly efficient, fully soft-switched, quasi-single-stage, isolated three-phase AC-DC conversion system, intended for applications demanding an ultra-wide output voltage range, such as dc current distribution systems. The proposed topology comprises a three-phase Unfolder, a third-harmonic current injection (CI) circuit, and a dual active bridge (DAB) converter utilizing an $LCL$ resonant tank. The low-frequency-switched Unfolder significantly reduces the size of dc-link capacitors and eliminates the need for external grid-side inductive filters; however, it introduces fundamental design and control complexities due to time-varying dc-link voltages. To overcome these challenges, this paper introduces a novel zero-voltage/zero-current-switching (ZVS/ZCS) assisting circuit for soft-switching of the CI leg throughout the grid cycle, establishes wide-range soft-switching-oriented design guidelines for the DAB–$LCL$ converter over 200 V–800 V output voltage range, and develops a phasor transformation-based small-signal modeling framework that enables robust controller design and stability evaluation under time-varying dc-link voltage conditions. Hardware validation results demonstrate that the system achieves a peak efficiency of 97.4% at the rated output power of 5 kW with 2.1% grid current total harmonic distortion, and an input power factor of 0.99. Moreover, high efficiencies ranging from 94.3%-97.4% are achieved over a 200 V-800 V output voltage range. Furthermore, modular configuration is validated with a centralized Unfolder and two dc-dc converters in input-parallel, output-series (IPOS) configuration at 10 kW output power and a total output voltage of 1.6 kV, achieving a rated power ac-dc efficiency of 97.24%.
Shubhangi Gurudiwan, Aditya Zade, Hongjie Wang et al.· IEEE Open Journal of Power E...· 0 citations
In the Phase II upgrade of the China Spallation Neutron Source, the linac system will achieve a beam energy upgrade from 80 to 300 MeV through the implementation of twenty 324 MHz spoke superconducting radio frequency (SRF) cavities and twenty-four 648 MHz elliptical SRF cavities. Each spoke cavity requires a dedicated solid-state power amplifier (SSPA) delivering 300 kW peak RF power at a pulse width of 1.2 ms and a repetition rate of 50 Hz. This paper presents the development and experimental validation of a novel pulsed GaN (Gallium Nitride) based SSPA system that employs high-power GaN HEMTs (high-electron-mobility transistors), a redundant direct-current supply subsystem, a compact power-combining network, and a modular architecture. The first prototype SSPA has been successfully built and tested. Measurement results demonstrate that the GaN-based PA modules provide 130% higher output power than conventional laterally diffused metal-oxide-semiconductor (LDMOS) technology at 324 MHz, thereby reducing the number of required amplifier units by 50% while maintaining sufficient power margin. The system exhibits excellent reliability, availability, and operational flexibility, meeting all design specifications.
Linyan Rong, Zhencheng Mu, Hexin Wang et al.· Review of Scientific Instrum...· 0 citations
Conventional resistive-type superconducting fault-current limiters (RSFCLs) rely exclusively on fault currents and temperature increases to trigger quenching, resulting in delayed fault response and excessive heat buildup under short-circuit conditions. To mitigate these limitations, this paper proposes a self-triggered, magnetic-field-excited superconducting current-limiting reactor (SCLR) integrated with a solenoidal magnet assembly. During the design and simulation phases, a segmented discretization method is employed to quantitatively characterize the gradient distribution of the external perpendicular field within the superconducting tapes and coils. This approach theoretically elucidates the mechanism by which spatially non-uniform magnetic fields influence current-limiting performance. DC short-circuit simulations show that the background magnetic field instantly reduces the critical current, rapidly transitioning the superconducting layer into a nonlinear resistive state. In contrast to the conventional topology, the proposed SCLR achieves two key performance improvements during short-circuit faults: it limits the peak fault current to just 45.9% of the value recorded with the conventional RSFCL scheme, and it reduces the maximum temperature rise by 1.4 K. The findings of this study provide a theoretical foundation and technical references for multi-field coupling modeling and structural optimization of magnetic-field-regulated current-limiting devices in DC grids.
The rapid adoption of fast-switching wide bandgap (WBG) semiconductor devices in motor-drive systems has introduced significant benefits in achieving high efficiency and high power density but also posed challenges associated with reflected overvoltage phenomena. Such reflected overvoltages impose severe high-frequency voltage stress on motor stator windings, which accelerate insulation degradation and undermine the reliability of motor stator windings. Traditionally, RLC $dv/dt$ filters have been used as an effective mitigation technique for limiting voltage slew rates and protecting the motor winding against these reflected overvoltages. However, these filters introduce excessively additional losses, size, and weight to the overall motor-drive systems. In contrast, the recently proposed smart coil circuit (SCC) has emerged as an alternative mitigation technique. This new approach enables effective suppression of reflected overvoltages with ultrahigh efficiency through its adaptive, ultracompact, and self-powered design. This article presents a comparative study of the smart coil mitigation technique versus the conventional RLC $dv/dt$ filter for overvoltage mitigation. The comparison focuses on operating efficiency, the effectiveness of mitigating overvoltage stress on motor stator windings, and identifying which mitigation technique is more effective for various operating conditions. Finally, comparative experimental validations based on a 2-hp motor-drive system demonstrate the effectiveness of both mitigation methods and provide an assessment of their strengths and limitations in WBG-based motor-drive systems.
Abdelrahman Habib, Mohamed Y. Metwly, Jiangbiao He· IEEE Journal of Emerging and...· 1 citation