High-voltage Switch Research Articles

Electrical wear performance of copper matrix composites reinforced with hybrid CNTs and TiB2 particles

PurposeCopper matrix composites are widely used in high-voltage switches, electrified railways and other electric friction fields. The purpose of this study is to improve its wear resistance and investigate the effect of hybrid carbon nanotubes (CNTs) and titanium diboride (TiB2) particles reinforced copper matrix composites on electrical wear performance.Design/methodology/approachCNTs and TiB2 particles were introduced into copper matrix simultaneously by powder metallurgy combined with electroless copper plating. Electrical wear performance of the composites was studied on self-made pin on disk electrical wear tester.FindingsThe results show that the friction coefficient and wear rate of (1CNTs–4TiB2)/Cu composite are respectively reduced by 40% and 25.3%, compared with single TiB2/Cu composites. The micron-sized TiB2 particles can hinder the plastic deformation of composites, and bear part of the load to weaken the wear rate of composites. CNTs with the self-lubricating property can form lubricating layer to reduce the friction coefficient of composites.Originality/valueThis work can provide a design method for further improving the wear properties of TiB2/Cu composites.

Design and analysis of an input‐series quasi‐resonant flyback high‐voltage SMPS based on an integrated transformer

An input-series quasi-resonant (QR) flyback high-voltage switching mode power supply (SMPS) based on an integrated transformer has been designed and analysed. It is capable of converting a high DC input voltage to lower DC voltage to power the control components of high-power converters in a DC microgrid. An integrated transformer, combined with identical duty cycle control, is adopted to achieve automatic equalization of the series modules effectively even without employing any voltage or current equalization control strategy, of which effect is analysed theoretically. The design of the control system, based on QR flyback SMPS is given, which is implemented by peak current control, and a DCM small-signal model for the designed SMPS is established, which indicates that the system has high stability and accuracy to ensure normal operation across a broad range of input voltages. Finally, the validity of the theoretical analysis and the proposed method is demonstrated by the development of a 48 W SMPS experimental prototype, which is composed of three input-series modules. The overall efficiency of the prototype has been improved due to the adoption of QR. The proposed design and analysis methods can be extended to other input-series isolated DC/DC topologies.

Design of 30 V High-Voltage Low-Power Radiation-Tolerant Analog Switch IC

In this study, a circuit- and device-level design was developed to improve the radiation tolerance of an analog switch integrated circuit (IC), which was fabricated using a commercial 0.35- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> bipolar–CMOS–DMOS (BCD) process. Both circuit- and layout-level approaches were used to improve the total ionizing dose (TID) tolerance of the IC. In the circuit-level approach, a level shift unit was used to reduce the amount of oxide traps. Under the layout-level approach, a ring gate and a doping ring were added to reduce the leakage current. Moreover, the optimum doping concentration of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$P_{\mathrm {WELL}}$ </tex-math></inline-formula> and length of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N_{+}$ </tex-math></inline-formula> drift zone were calculated for the n-MOSFET based on simulations to obtain the best device structure and improve the single-event burnout (SEB) tolerance. The radiation tolerance was tested experimentally. The results indicated that the newly designed 30-V high-voltage low-power analog switch chip had a TID tolerance >300 krad(Si) and a SEB tolerance >75 MeV cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /mg, which are useful to improve the radiation-tolerant capability of high-voltage analog switches.

A High-Voltage Series-Stacked IGBT Switch With Output Pulse Shaping Capability to Reduce EMI Generation

A High-Voltage Series-Stacked IGBT Switch With Output Pulse Shaping Capability to Reduce EMI Generation

Ultra-compact nonvolatile plasmonic phase change modulators and switches with dual electrical–optical functionality

Programmable photonic integrated circuits (PICs) are the foundation of on-chip optical technologies, with the optical modulators being one of the main building blocks of such programmable PICs. However, most of the available modulators suffer from high power consumption, low response time, and large footprint. Additionally, they show a large resistance modulation; thus, they require high switching voltage. In consequence, they operate much above CMOS-compatible voltages of 1.2 V and with high insertion losses. Furthermore, the state and information they carry are lost once the power is turned off—so, they are volatile. Thus, realizing modulators and phase shifters that overcome all those problems still remains a challenge. To overcome some of those limitations, the nonvolatile phase change materials implemented in the plasmonic structures are proposed that can offer many advantages as result of high electric field interaction with nonvolatile materials. Consequently, novel plasmonic nonvolatile switches proposed here can operate by phase modulation, absorption modulation, or both and under zero-static power. For the first time, the nonvolatile phase modulator is proposed that requires only 230 nm long active waveguide to attain full π phase delay with an insertion loss below even 0.12 dB. Simultaneously, under the requirements, it can operate as an amplitude modulator with an extinction ratio exceeding 2.2 dB/μm while the insertion losses are kept below 0.185 dB/μm. Furthermore, the heating mechanism can be based on the external heaters, internal heaters, electrical (memory) switching, or optical switching mechanism, which provide a lot of flexibility in terms of a design and requirements.

Research on Characteristics of Copper Foil Three-Electrode Planar Spark Gap High Voltage Switch Integrated with EFI

In view of the low-energy explosion foil detonation system’s requirements for the integration technology of high-voltage switches and technical overload resistance technology, a magnetron sputtering coater is used to sputter copper film on the surface of the substrate. The thickness is 4.0 μm, the radius of the main electrode is 4 mm, the trigger electrode is 0.6 mm and 0.8 mm, and the main gaps are 0.8 mm, 1.0 mm, 1.2 mm mm, 1.8 mm, 2.0 mm, 2.2 mm, and 2.6 mm. Copper foil three-electrode planar spark gap high voltage switches are designed and manufactured; and the static self-breakdown characteristics, dynamic operating characteristics, and discharge life characteristics of the three-electrode planar spark gap high voltage switch based on copper foil are studied in this paper. The test results show that with the increase of the main electrode gap from 0.8 mm to 2.6 mm, the self-breakdown voltage of the planar spark gap switch increases, and the working voltage also increases. When the main electrode gap is a maximum of 2.6 mm, the self-breakdown voltage of the switch can reach 3480 V, which indicates that the maximum operating voltage of the switch is 3480 V. When the charging voltage is 2.0 kV, with the increase of the main electrode gap from 0.8 mm to 2.6 mm, the minimum trigger voltage value of the planar spark gap switch increases from 677 V to 1783 V (a = 0.6 mm), and from 685 V to 1766 V (a = 0.8 mm), the switch on time is 16 ns, 22 ns, 28 ns, 48 ns, 64 ns, 77 ns, 93 ns (a = 0.6 mm), and 26 ns, 34 ns, 51 ns, 67 ns, 81 ns, 102 ns (a = 0.6 mm). With the increase of the gap between the two main electrodes of the switch, the maximum static working voltage of the three-electrode plane spark gap high-voltage switch increases, the minimum trigger voltage value also increases, and the on-time of the switch gradually becomes longer. The peak current of the discharge circuit decreases and the dynamic impedance and inductive reactance of the switch also increase; as the width of the trigger electrode increases, the minimum trigger voltage decreases, the dynamic impedance and inductance decrease, and the switch operating voltage with the same parameters is higher. The easier the switch is to turn on, the lower the minimum trigger voltage. The electrode thickness of the three-electrode plane spark gap switch has a certain influence on the field strength and the service life of the switch. The results of this study provide useful references for promoting the research and development of LEEFIs.

Diamond semiconductor and elastic strain engineering

Diamond, as an ultra-wide bandgap semiconductor, has become a promising candidate for next-generation microelectronics and optoelectronics due to its numerous advantages over conventional semiconductors, including ultrahigh carrier mobility and thermal conductivity, low thermal expansion coefficient, and ultra-high breakdown voltage, etc. Despite these extraordinary properties, diamond also faces various challenges before being practically used in the semiconductor industry. This review begins with a brief summary of previous efforts to model and construct diamond-based high-voltage switching diodes, high-power/high-frequency field-effect transistors, MEMS/NEMS, and devices operating at high temperatures. Following that, we will discuss recent developments to address scalable diamond device applications, emphasizing the synthesis of large-area, high-quality CVD diamond films and difficulties in diamond doping. Lastly, we show potential solutions to modulate diamond’s electronic properties by the “elastic strain engineering” strategy, which sheds light on the future development of diamond-based electronics, photonics and quantum systems.

High Gain Converter with Improved Radial Basis Function Network for Fuel Cell Integrated Electric Vehicles

In a recent trend, electric vehicles (EV) have been facing various power quality issues, so fuel cells (FC) are considered the best choice for integrating EV technology to enhance performance. A fuel cell electric vehicle (FCEV) is a type of EV that uses a fuel cell combined with a small battery or super-capacitor to power its on-board electric motor. However, the power obtained from the FC system is much less and is not enough to drive the EV. So, another energy source is required to deliver the demanded power, which should contain high voltage gain with high conversion efficiency. The traditional converter produces a high output voltage at a high duty cycle, which generates various problems, such as reverse recovery issues, voltage spikes, and less lifespan. High switching frequency and voltage gain are essential for the propulsion of FC-based EV. Therefore, this paper presents an improved radial basis function (RBF)-based high-gain converter (HGC) to enhance the voltage gain and conversion efficiency of the entire system. The RBF neural model was constructed using the fast recursive algorithm (FRA) strategy to prune redundant hidden-layer neurons. The improved RBF technique reduces the input current ripple and voltage stress on the power semiconductor devices to increase the conversion ratio of the HGC without changing the duty cycle value. In the end, the improved RBF with HGC achieved an efficiency of 98.272%, vehicle speed of 91 km/h, and total harmonic distortion (THD) of 3.12%, which was simulated using MATLAB, and its waveforms for steady-state operation were analyzed and compared with existing methods.

Improved limit of detection of a high-resolution fs-LIMS instrument through mass-selective beam blanking

Laser Ablation Ionisation Mass Spectrometry (LIMS) is an important quantitative method for chemical analysis of solids. Current limits of detections (LoDs) of LIMS instruments are in the ppm to sub-ppm range (atomic fractions), while other commonly used techniques for solid sample analysis reach LoDs at ppb levels or even below. This study presents the implementation of mass-selective beam blanking in the Laser Mass Spectrometer – Gran Turismo (LMS-GT) to improve the instruments’ detection limit. LMS-GT is a high-performance time-of-flight LIMS instrument coupled to a femtosecond laser ablation ion source reaching micrometre spatial resolutions and mass resolutions ≳ 12′000. A fast high voltage switch was developed in-house to induce potential changes at an Einzel lens at the intermediate time focus of the ion trajectory, leading to short deflections of the ion beam and hindering selected species from reaching the detector. The intensities of single mass lines are reduced with 100% efficiency to below the noise floor when blanked. The detector gain can safely be increased while blanking the most intense mass lines simultaneously, thus improving the detection limit. The LoD of LMS-GT prior to the installation of the mass-selective blanking device was at ppm level (at. frac.) with few sub-ppm detections, the installation pushed it to the lower ppb range, without compromising the initial performance. This emphasises that fs-LIMS can be a powerful quantitative technique for the chemical analysis of solids, with the potential to reach the levels of mass spectrometric analysis achievable with Secondary Ion Mass Spectrometry (SIMS) and Laser Ablation–Inductively Coupled Plasma–Mass Spectrometry (LA-ICP-MS).

Real-Time Monitoring of High Voltage Switch Based on CAD

In the process of online real-time monitoring of intelligent digital filter high-voltage switchgear, the mechanical state diagnosis of high-voltage circuit breaker is based on fully understanding the mechanical characteristics of each component of circuit breaker. In this paper, K-means clustering algorithm is applied to the mechanical state detection of digital filter high-voltage switchgear. The mechanical state of the digital filter high-voltage switchgear is monitored in real time by using 126 kV GIS. Through fault simulation experiment and mechanical stability experiment, the corresponding changes of characteristics of each mechanical component of circuit breaker in signal waveform and corresponding data changes are found. The experimental results show that this method has good running speed and stability and is more suitable for the real-time monitoring of intelligent digital filter high-voltage switchgear.

Study of Current Collapse Behaviors of Dual-Gate AlGaN/GaN HEMTs on Si

Surface traps on GaN-based HEMTs (high-electron-mobility transistors) usually result in the increase of channel on-resistance. It becomes worsen when short pulses are applied during high-frequency and high voltage switching. Here we present a dual-gate transistor structure to suppress the dynamic on-resistance increase. The auxiliary gate under a proper fixed voltage is able to induce additional electrons to compensate the channel carrier loss during main gate switching, leading to a lower dynamic on-resistance. In this work, we benchmarked the fundamental electrical properties of both single-gate and dual-gate HEMTs. We further extracted the dynamic electrical properties by stressing the devices with short pulses. The results suggest a significant mitigation of current collapse of a dual-gate HEMT under a proper bias applied on the auxiliary gate electrode. The physical mechanism based on the charge distribution in the channel is employed to explain the observations.

ФЕРРОРЕЗОНАНСНЫЕ ПЕРЕНАПРЯЖЕНИЯ В ЭЛЕКТРОУСТАНОВКАХ 6–220 кВ: ТЕОРИЯ И РЕЗУЛЬТАТЫ ЭКСПЕРИМЕНТАЛЬНЫХ ИССЛЕДОВАНИЙ

Relevance The article is devoted to the systematization and generalization of theoretical and experimental studies of ferroresonance overvoltages in electrical installations 6–220 kV. The need to study this issue is associated with the active introduction of distributed generation facilities into distribution networks, as well as medium and low voltage networks. In power districts with distributed generation facilities, the settings and operation algorithm of relay protection and automation devices differ from the traditional ones used in centralized power supply. The generation parameters and the nature of electromechanical transients also differ, which is caused by the low dynamic stability of generating plants based on synchronous generation and the use of network inverters with energy storage in electronic generation. Thus, due to significant differences in the parameters of the network operation mode with and without distributed generation objects, it is necessary to revise many well-known technical problems, including the issue of ferroresonant processes. Electrical installations of 6–220 kV were chosen as the object of research, since the concept of distributed generation does not imply backbone networks, and the maximum installed power of an individual facility is limited by 25 MW. Aim of Research Aim of research is to systematize and summarize the theoretical and experimental studies of ferroresonance overvoltages in electrical installations 6–220 kV. Research methods To study the circuit-mode conditions for the occurrence of ferroresonant processes in electrical installations of 6–220 kV, an analysis of foreign and domestic publications, standards was carried out, and the theoretical foundations of electrical engineering and the theory of nonlinear electrical circuits were used. Results The physical essence of the phenomenon of ferroresonance, the conditions for the occurrence of ferroresonant processes and measures to prevent them in medium and high voltage networks, experimental studies of ferroresonant processes are considered. The ferroresonant process consists in compensating the inductive and capacitive resistances in the oscillatory circuit with a saturated inductance core. There are various modes of ferroresonance, which are determined by the initial conditions: fundamental, subharmonic, aperiodic and chaotic. A prerequisite for the occurrence of a ferroresonant process is the power of the power source sufficient to saturate the inductance core. Non-linear inductance that can participate in the formation of an oscillatory circuit are voltage transformers, power transformers, shunt reactors. The capacity of the circuit can be a power line, a busbar system, a capacitor bank, shunt capacitors of switches. Hardware and operational measures to protect against ferroresonant processes in electrical installations are aimed at changing the capacitance or inductance of network elements that may participate in the formation of a ferroresonant oscillatory circuit, preventing the formation of such a circuit or reducing its quality factor. The results of experimental studies of ferroresonant processes do not contradict the guidelines for protection against resonant voltage increases in electrical installations. Keywords: ferroresonance overvoltages, distributed generation, ferroresonant process, electrical installation, busbar system, high-voltage switch, non-linear inductance

Linearity Analysis of High-Voltage RF Switches for Antenna Tuning Applications

An analysis describing nonlinearities in shunt aperture tuning radio frequency (RF) switches operating in OFF-state is presented in this article. The focus is put on the analysis of second- and third-order nonlinear products and their power distribution as a function of geometry of high-voltage (HV) field-effect-transistor (FET)-based RF switch. According to the results of analysis, the third-order nonlinear product can be reduced by 6 dB at the expense of 4.1 dB increase in the second-order product by doubling the stack size and transistor width used in the switch. The analytical findings are verified with measurements for which two integrated circuits (ICs) were designed and manufactured in Infineon 130-nm RF switch technology. The experiment demonstrated reasonable hardware-to-model correlation, showing around +8 and −7 dB difference in second and third harmonic and intermodulation (IM) products between high-voltage (HV) and low-voltage (LV) RF switches, respectively.

A broadband optical fiber transmission-based time domain measurement system for nanosecond-level transient electric field.

A novel nanosecond transient electric field (E-field) measurement system is developed in this paper to measure the E-field pulse caused by the operation of the high-voltage switch (switching E-field pulse) in the substation. An electrically small rod antenna is used as the receiving antenna and is matched by the operational amplifier with high input impedance to achieve broadband frequency response and stable working performance. A broadband analogoptical fiber transmission system is further designed based on the high-frequency circuit model of the electronic components. Unlike the traditional frequency domain E-field measurement methods, the developed measurement system can directly output the time domain waveform of the switching E-field pulse. It also has the advantages of adjustable sensitivity, portability, and anti-electromagnetic interference. The calibrated measurement bandwidth ranges from 200Hz to 680MHz. Furthermore, the switching E-field pulse in an ultra-high voltage substation is measured and analyzed to verify the effectiveness of the fabricated measurement system.

A Quasi-Two-Level Medium-Voltage SiC MOSFET Power Module With Low Loss and Voltage Self-Balance

High-voltage and fast-switching silicon carbide (SiC) power modules are needed to construct high-voltage and high power-density converters. Stacking multiple low-voltage SiC devices to increase the equivalent blocking voltage shows advantages in <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> -state resistance, current capacity, and cost over one single high-voltage device. An indirect series-connected SiC MOSFET power module using quasi-two-level hybrid-clamp topology is proposed in this article. The voltages across the devices are automatically balanced with an open-loop modulation strategy to avoid sensors and control algorithm. Moreover, only ceramic capacitors are needed besides the MOSFETs and diodes in the topology. Thanks to this, the topology was highly integrated into a power module using SiC dies, which is equivalent to a general-purpose two-level medium-voltage SiC MOSFET power module. The switching losses of the power module show advantages over other stacking methods and even a single high-voltage switch and it can be evaluated with a two-level half-bridge (HB). To achieve this, the automatic voltage-balancing performance is analyzed in detail and the parasitic output capacitance in the topology is investigated, based on which the design considerations are presented. The simulation results from LTspice confirm the voltage-balancing and a 3600V/20A HB power module is built in the lab and the experimental results verify the design.

Design and Analysis of P-GaN/N-Ga₂O₃ Based Junction Barrier Schottky Diodes

This article proposes a new junction barrier Schottky diode (JBSD) design based on P-GaN/N-Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> heterojunction with faster switching characteristics and higher breakdown ability than the traditional two-terminal power switches. Calibrated models have been used for technology computer-aided design (TCAD) simulations of the proposed JBSD after a comprehensive review of various physical models and model parameters in the present literature. Analysis in terms of static and transient behavior for a varying proportion of PN area to the Schottky contact area (PN:SBD ratio) was looked upon for the JBSD. With the increase of PN:SBD ratio, the reverse voltage handling capability increased as expected, but the reverse recovery time and maximum reverse recovery current decreased. This might be counterintuitive initially, as with an increase in PN:SBD ratio, the PN behavior would dominate over SBD, and slower transient behavior is expected. However, due to redistribution of electric field and the reduction in depletion capacitance across the JBSD with increase in PN:SBD ratio, JBSD with PN:SBD ratio of 8 gives us a breakdown at 1890 V and a switching time of 9.72 ns. Furthermore, a comparison of the transient response with state-of-the-art SiC Schottky diode reveals the efficiency of the proposed structure in terms of reverse recovery parameters to be significantly better, translating to 7.4 times lower power losses at higher frequencies. Overall, the design and analysis presented here suggest the promising potential of P-GaN/N-Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> vertical devices for high-voltage and fast switching applications.

Self-terminating barium ion laser at 614.2 nm

Experimental results of the laser operating on the barium ion self-terminating transition 6p2P3/2o - 5d2D5/2 at λ=614.2 nm investigations are presented. Through a series of tests, we demonstrated a significant improvement of the output characteristics of this laser by employing (i) a novel high-voltage nanosecond switch capable to operate at high pulse repetition frequency (more than 50 kHz), and (ii) hydrogen addition to the active medium. Achieved steady-state average output power in the burst-mode operation amounted to 125 mW with laser pulse duration of ≈5 ns at half-maximum.

Research on the triggering process of a laser-triggered vacuum switch

The laser-triggered vacuum switch (LTVS) is a type of high-voltage closing switch with broad application prospects in pulsed-power technology. Research into the triggering process of the LTVS is not only helpful to understand the triggering mechanism of the LTVS but also beneficial to the optimization of the LTVS. In this paper, the triggering process and the delay time of a LTVS with a Ti–KCl mixture target was analyzed theoretically. A numerical simulation was performed to describe the laser-target ablation process and the expansion dynamics of the initial plasma. The simulation results were compared with the experimental results. It is clear that the triggering process and delay time strongly depend on the laser intensity. As the laser intensity rises, the velocity of initial plasma increases, resulting in a shorter delay time of the LTVS. Increasing the gap voltage can also shorten the delay time.

Development Trend of High-voltage Switching Technology for the Sustainable Society

Development Trend of High-voltage Switching Technology for the Sustainable Society

A Transceiver ASIC for a Single-Cable 64-Element Intra-Vascular Ultrasound Probe

This article presents an application-specific integrated circuit (ASIC) designed for intra-vascular ultrasound imaging that interfaces 64 piezoelectric transducer elements to an imaging system using a single micro-coaxial cable. Thus, it allows a single-element transducer to be replaced by a transducer array to enable 3-D imaging. The 1.5-mm-diameter ASIC is intended to be mounted at the tip of a catheter, directly integrated with a 2-D array of piezoelectric transducer elements. For each of these elements, the ASIC contains a high-voltage (HV) switch, allowing the elements to transmit an acoustic wave in response to an HV pulse generated by the imaging system. A low-noise amplifier then amplifies the resulting echo signals and relays them as a signal current to the imaging system, while the same cable provides a 3-V supply. Element selection and other settings can be programmed by modulating configuration data on the supply, thus enabling full synthetic aperture imaging. An integrated element test mode measures the element capacitance to detect bad connections to the transducer elements. The ASIC has been fabricated in a 0.18- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> HV CMOS technology and consumes only 6 mW in receive. Electrical measurements show correct switching of 30-V transmit pulses and a receive amplification with a 71-dB dynamic range, including 12 dB of programmable gain over a 3-dB bandwidth of 21 MHz. The functionality of the ASIC has been successfully demonstrated in a 3-D imaging experiment.