High-voltage Switch Research Articles

Modular pulsed power supply for characterization of high-power microwave devices.

Developing a robust and reliable high-voltage (HV) pulse power system (PPS) is essential for the characterization and testing of microwave tubes and industrial applications. This paper presents the design, simulation, and implementation of a modular and versatile high-voltage pulse power supply used in microwave device characterization and testing. A microcontroller-based digitally controlled pulse generation unit is also developed to generate the trigger pulses for high-voltage switching modules to control the turn-ON and turn-OFF of the switching devices. The digitally controlled pulse generation unit provides better resolution of pulse width, pulse repetition frequency, and system protection over the entire range of operations. The pulse generation and control circuit controls the pulse repetition frequency (PRF) and pulse wide (PW). The PRF and PW can be varied from 100 to 1000Hz and 10 to 100 µs, respectively. The experimental prototype with ten series-connected high-voltage modules is connected to achieve a 25kV pulsed output voltage. The experimental results of HV-PPS on a resistive dummy load and 5GHz klystron tube are presented in this work.

Synaptic Device based on Resistive Switching Memory using Single-walled Carbon Nanotubes

Recently, research has been conducted on a biomimetic system called artificial neural networks (ANNs) to overcome the limits of Von Neumann’s system. Spiking neural networks (SNNs) in ANNs are hardware systems that implement NNs’ low-power parallel processing. The electrical characteristics of synaptic devices, which affect learning and memory, are important in SNN construction. Synaptic devices based on resistive switching are called memristors and have sufficient learning capabilities, such as spike-timing-dependent plasticity gradual switching [1]. However, memristors require high switching voltages and currents, resulting in high power consumption. To reduce the operation voltage of the synapse, new materials must be developed for the switching oxide and metal electrode. The conventional memristor structure comprises metal-oxide-metal (MOM) or metal-oxide-N+Si (MOS). This study proposes a synaptic device with single-walled carbon nanotubes (SWCNTs) with excellent electrical and mechanical properties to lower the switching voltage and fabricate a metal-oxide-SWCNTs-N+Si (MOCS)-structured synaptic device using SWCNTs as a metal electrode, as shown in Fig. 1 [2]. Finally, the electrical characteristics of MOM, MOS, and MOCS structures are analyzed and compared.

Class-C Pulsed Power Amplifier with Voltage Divider Integrated with High-Voltage Transistor and Switching Diodes for Handheld Ultrasound Instruments

A novel Class-C pulsed power amplifier with a voltage divider integrated with a high-voltage transistor and switching diodes is proposed to reduce DC power consumption and increase the maximum output power for handheld ultrasound instruments. Ultrasonic transducers in ultrasound instruments are devices that convert electrical power into acoustic power or vice versa, which are triggered by power amplifiers. Efficient power conversion is also very important to avoid thermal issues in handheld ultrasound instruments owing to limited battery power and excessive heat generation caused by the enclosed structures of the handheld ultrasound instruments. Consequently, higher output power and lower DC power consumption are desirable for a power amplifier. Therefore, a circuit to control power amplifiers was developed. The measured output power (94.66 W) and DC power consumption (2.12 W) when using the proposed circuit are better than those when using the existing Class-C pulsed power amplifier (74.90 W and 2.77 W, respectively). In the pulse-echo measurement mode, the echo amplitude (12.34 mVp-p) and bandwidth (27.74%) of the proposed Class-C pulsed power amplifier were superior to those of the existing Class-C pulsed power amplifier (4.38 mVp-p and 23.25%, respectively). Therefore, the proposed structure can improve the performance of handheld ultrasound instruments.

Fuel vehicle improvement using high voltage gain in DC-DC boost converter

Fuel cell electric vehicles (FCEV) are becoming increasingly popular among manufacturers as carbon dioxide emissions and fuel economy rules have become more stringent. Fuel-cell vehicles often have lower output voltages than those required by the DC bus; therefore, the output voltage decreases rapidly as the output current increases. In this critical circumstance, it is essential to have a DC-DC converter for FCEVs with a high switching frequency and voltage gain. Furthermore, DC-DC booster converters are used in FCEV systems to achieve a high voltage gain. Over a 40 V input range, MATLAB tests the modified converter for gains of approximately five times the input voltage gain. Furthermore, when the fuel cell was operational, a converter efficiency of approximately 90% was measured.

A study on improving the efficiency of non-isolated buck-boost bidirectional DC–DC converter

ABSTRACT In battery-based systems such as hybrid electric propulsion system for ships that use electric propulsion and DC grid, bidirectional converters are often used as interfaces between high-voltage power sources and low-voltage batteries for the purpose of storing excess energy and the fields of application for bidirectional converters are steadily expanding. This study proposes a new bidirectional converter with a high voltage conversion rate and low switch voltage stress. The proposed converter allows current to flow between modules by adding only one capacitor compared to a conventional bidirectional converter. To check the effectiveness of the proposed method, PSIM software by Powersim co. Ltd. was used to perform simulation tests. It was confirmed that the high voltage conversion rate was 4 times that of a conventional bidirectional converter in step-up mode and 1/4 that of a conventional bidirectional converter in step-down mode. Therefore, low-voltage components, such as MOSFETs, GTOs, etc., can be applied in the DC–DC converters thanks to the 1/4 voltage that is required in each switching time.

Off-the-Shelf Diodes as High-Voltage Opening Switches

A semiconductor opening switch (SOS) (also known as SOS diode) is a solid-state nanosecond switch of gigawatt power level. Due to its high pulse repetition rate, long lifetime, and maintenance-free capability, the SOS diodes are becoming increasingly attractive for use in solid-state pulsed power generators. However, the lack of SOS diode manufacturers prevents the widespread use of this technology. This work demonstrates the ability of off-the-shelf diodes to operate in the SOS mode. A wide range of off-the-shelf diodes including rectifier, fast recovery, avalanche, and transient-voltage-suppression (TVS) diodes have been tested as high-voltage opening switches. An experimental arrangement based on a saturating pulse transformer (PT) was developed to test off-the-shelf diodes in the SOS mode. The results obtained were compared with the existent top of the range SOS diodes, used as reference. Two versions of the experimental setup with the initially stored energy of 25 mJ and 10 J were used. The following pulse parameters were obtained using off-the-shelf diodes: 1) peak voltage impulse of 3 kV and rise time of 10 ns with a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$110 \Omega $ </tex-math></inline-formula> load (for the 25 mJ setup) and 2) peak voltage impulse of 80 kV and rise time of 20 ns with a 1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{k}\Omega $ </tex-math></inline-formula> load (for the 10 J setup). Based on the parameters obtained, the door is opened for a future use of off-the-shelf diodes as opening switches in a wide range of solid-state-based pulsed power systems.

Extraction of Dynamic Threshold Voltage in Resistive Load Hard Switching Operation of Schottky-Type p-GaN Gate HEMT

Threshold voltage (VTh) drift of Schottky-type p-GaN gate high-electron mobility transistor (HEMT) was analyzed under high-voltage and hard switching conditions with a resistive load (R-Load). To overcome the distortion in the drain current (ID) – gate voltage (VG) curve caused by the internal drain capacitance (IDisp) charging current during the switching transients, a method is presented to accurately measure dynamic VTh through appropriate correction of IDisp. The dynamic variation of VTh was tracked with a gate-drive rise/fall times of 200 ns. During the switching operation, VTh increases rapidly at the beginning and then saturates at a stable value. This is attributed to the gate forward current during turn-on that increases the hole depletion of the p-GaN gate through the AlGaN barrier. The dynamic VTh increases linearly at a rate of 40% with the increase of gate turn-on voltage. VTh is independent of duty cycle but minorly increases with frequency at high voltages, suggesting that channel hot electrons be injected into the AlGaN barrier and p-GaN.

Multi-spectral Characteristics of Arc Discharge in Switch Cabinet

The partial discharge (PD) in high voltage switch cabinet might develop into non-penetrating or penetrating arc under extreme conditions, which can lead to insulation failure in severe case. From the optical radiation characteristics of discharge, an optical detection method for abnormal arc was proposed. Multi-spectral characteristics of arc discharge were obtained by the synchronous monitoring of ultraviolet, visible, and infrared optical signals, and the average intensity of light pulse, average light intensity ratio and the light intensity ratio of three bands were analyzed. The results show that the average light pulse intensity of arc discharge and the proportion of three-band light intensity have obvious characteristics and there is a good corresponding relation between the amplitude of discharge light signal and the applied voltage.

A Multi-MHz Active Clamp Topology for High Cost-Performance Wireless Power Transfer

The single-switch topologies, e.g., the Class E topology, have the advantages of low component count, no shoot-through problem, simple driving circuit, which make it more suitable for high frequency low/medium-power wireless power transfer (WPT) applications. However, due to the high switch voltage stress, narrow soft switching range, bulky input choke, or ac inductor, its power delivery capability and applications are limited. In order to solve these problems, this article proposed a novel active clamp topology for high cost-performance medium-power WPT systems. The proposed topology offers low component count with no bulky inductor and low switch voltage stress, leading to high power-density, low cost, and compact size, i.e., high cost-performance for WPT applications. And the switch peak voltage can be adjusted and the soft switching operation can be achieved in a wide load range by designing the compensation capacitor and clamp capacitor. In this article, the detailed theoretical analysis and parameter design are discussed and the proposed topology is compared with the existing single-switch topology in terms of voltage stress, cost, and component count. A 120 W and 1 MHz active clamp WPT system is built and a 92.4% system efficiency is achieved with high cost-performance, which validate the feasibility of the proposed topology and the theoretical analysis.

Fast silicon carbide MOSFET based high-voltage push-pull switch for charge state separation of highly charged ions with a Bradbury-Nielsen gate.

In this paper, we report on the development of a fast high-voltage switch, which is based on two enhancement mode N-channel silicon carbide metal-oxide-semiconductor field-effect transistors in push-pull configuration. The switch is capable of switching high voltages up to 600V on capacitive loads with rise and fall times on the order of 10ns and pulse widths ≥20ns. Using this switch, it was demonstrated that, from the charge state distribution of bunches of highly charged ions ejected from an electron beam ion trap with a specific kinetic energy, single charge states can be separated by fast switching of the high voltage applied to a Bradbury-Nielsen Gate with a resolving power of about 100.

Characteristics and Underlying Physics of Bipolar Corona Discharge of Floating Conductor

Bipolar corona discharge is the fundamental phenomenon that preoccurs in air breakdown for nongrounded objects facing a high-voltage source, which sets important bases for aircraft protection crossing thunderclouds and improvement of high-voltage switches with floating conductors, while this phenomenon has not been fully understood to date. This article proposes a bipolar corona plasma model (BCPM) based on the plasma hydrodynamic process and the chemical reactions of air discharge. The numerical analysis of the charged particle distribution matches the experimental result of the bipolar corona discharge appearance. Furthermore, the characteristics of bipolar corona discharge are described from the perspective of electric field and electron current density at the two opposite ends of the floating conductor. Results show that, at the positive end, the corona discharge has a long columnar shape in a faint light blue. While at the negative end, the corona presents a spherical shape in a stronger luminous light purple. There exists a density extremum at the position 0.03 cm away from the conductor ends in the distribution of electrons, where a low electron density zone with a concentration of 0.42 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times \,\,10^{13}\,\,\text{m}^{-3}$ </tex-math></inline-formula> forms at the positive end, while electrons group to a high density of 2 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times \,\,10^{16}\,\,\text{m}^{-3}$ </tex-math></inline-formula> at the negative end. The geometric length of the high-density ions zone is enlarged by 2 times at the positive end compared to the negative end. The peak electric field at the negative end is about 1.5 times stronger than the electric field at the positive end, consistent with the space charge distribution at the positive and negative ends. The unbalance of the emission and entry of electron current results in a slightly positive polarity for the floating conductor. This study can be consulted for shedding light on the underlying physics of bipolar corona discharge of floating conductors.

Gas sensitivity and mechanism of metal-modified MoSe2 to air decomposition products in air-insulated switch cabinet

Metal (Pd, Pt, and Ni) modified MoSe2 are proposed to diagnose the partial discharge by detecting the air decomposition products: NO, CO, and NO2 existing in the insulation equipment of high-voltage switch cabinets. Based on the first-principle calculation, the most stable structure of the metal-modified MoSe2, and optimal gas adsorption structure of gas molecules on metal-modified MoSe2 were obtained. The adsorption energy and charge transfer during the adsorption process were calculated, and the total and projected state of density and molecular orbital changes were analyzed. The results showed that all of the gas adsorptions tend to be chemical adsorption, which provides a key basis for gas detection. The calculation results and theoretical analysis in this paper can be used to design Pd, Pt, and Ni modified MoSe2 gas-sensing material to detect NO, NO2, and CO components in the insulation equipment of high-voltage switch cabinet.

Compact Solid-State Marx Modulator With Fast Switching for Nanosecond Pulse

This article describes the compact solid-state Marx modulator (SSMM) with a fast rising time and a short pulsewidth based on the modular structure. By stacking of the TO-263-7 packaged silicon carbide <small>mosfet</small>s having high voltage and fast switching capabilities, the designed circuit consists of three components, including the Marx capacitor, an <small>on</small> switch for applying pulse to the load, and an <small>off</small> switch to pull down the pulse. The <small>off</small> switch connected in parallel with load is chosen as a <small>mosfet</small> instead of a diode that is used in the conventional Marx generator. Because the <small>off</small> switch provides a discharging path for the stored energy on the parasitic capacitance, it is highly related to the fast falling time. In order to provide complementary driving signal and power for <small>on&#x002F;off</small> switches, the simple control algorithm with a minimum component count and a reliable drive circuit against the noise are proposed. In addition, the synchronization of all the gate signals and a compact configuration for minimizing the stray inductance are essential to shorten the rising, falling, and pulsewidth. Based on the proposed circuit, the following specifications of the developed SSMM are achieved: the output voltage of 10 kV, the pulsewidth of less than 50 ns, and the rising and falling times of less than 15 ns.

High-performance memristor based on MoS2 for reliable biological synapse emulation

Inspired by the neural network of the human brain, neuromorphic emulation for memorizing and processing data using electronic devices has attracted widespread intention. The conductance of memristor device can be changed by the charge flowing through it, which is analogical to the variation of synaptic plasticity with the applied external stimulation. However, the high switch voltage and inferior stability of memristor limit the further application to the imitation of biological synapse. Here, a memristor based on large-area MoS2 with vertical structure Al/MoS2/Cu is constructed, which is deposited by magnetron sputtering system on aluminum foil. The memristor presents superior stability and robustness, and has a small set and reset voltages with narrow variation distribution. More importantly, by applying relevant pulse sequence, the essential synaptic behaviors are mimicked by using the memristor based on MoS2, including paired-pulse facilitation (PPF) and spiking-time-dependent plasticity (STDP), etc.

Speed-Power Improvement in High-Voltage Switches Employed in Multielectrode Arrays

In multi-electrode arrays (MEAs), for electrical recording and electrical stimulation, high voltage (HV) switches are employed to build an analog multiplexer to conduct either a HV stimulation signal from the pulse generator circuit to an electrode or a low-voltage noise-sensitive signal from the electrode to a recording stage. In this brief, a new circuit structure is proposed for HV switches that significantly improves their switching speed, reduces their power dissipation, and also employs a minimum number of bulky HV devices. In order to reduce the transition time of the proposed switch without consuming a large amount of power, during the transition time that the switch is turning on/off, a large current flows through the driver circuit of the switch to turn the switch on/off rapidly; however, after the transition times, this current is significantly reduced to save power. Based on the proposed HV switch, a multiplexer structure has been implemented in 25-V, 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> CMOS IC technology and the measurement results prove its efficacy. Supplied with 25 V and operating with 300 nA current consumption, this switch swings over 20 V with a relatively constant on-resistance of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$100 \Omega $ </tex-math></inline-formula> and features a 80 ns transition time.

Progress in the Preparation of Large-Size High-Performance CuCr Alloys

CuCr contact material, whose mass fraction of Cr is generally in the range of 25% to 50%, is one of the most desirable contact materials for medium- and high-voltage vacuum switches. The homogeneity and denseness of CuCr alloy are the keys to its application. The infiltration and powder sintering have defects, such as uneven distribution of Cr phase, and great difficulties in preparing high-performance CuCr alloys with low gas content; the equipment investment in the vacuum consumable arc melting method is large and the production cost is high, while mechanical alloying, vacuum induction melting, and laser-selective melting as new technologies are still in the laboratory stage. From the perspective of surface modification treatment and multicomponent alloying, refinement of Cr phase grains can improve the properties of CuCr alloy. The new process of aluminothermic reduction-electromagnetic coupling refining-water and gas composite rapid cooling takes oxides as raw material and obtains a fully miscible CuCr alloy melt by aluminothermic reduction theoretically at 2848K, followed by secondary refining under electromagnetic field coupling and water-gas composite cooling and casting, which can obtain alloy ingots of 50 mm in diameter and 10 mm in height. The density and hardness of CuCr alloy prepared by this process as vacuum contact material are better than the requirements of GB/T 26867-2011, so this process has the potential to become a new-generation preparation method for large-size homogeneous high-performance CuCr alloy.

Research on Power System Monitoring System Based on Computer Ubiquitous Internet of Things Technology

This article uses the current ubiquitous power Internet of Things, sensor technology, detection technology, communication technology and the application of hierarchical distributed structure to design a set of intelligent substation online monitoring system. Real-time monitoring of the operating status of main equipment such as high-voltage switches and transformers in substations, alarms and early warnings of potential faults in the equipment, and transmission of monitoring data and alarm data to the Internet through wired or wireless means to achieve remote data monitoring. It has good reliability and flexible scalability.

Structural and Algorithmic Synthesis of Three-Phase Traction Voltage Inverters

An approach to the structural and algorithmic synthesis of power electronic devices based on multichannel energy flow transformation is further developed. Previously, the obtaining of a high-current output with current-limited capabilities of the used semiconductor switches was considered [1]. In this paper, the approach is extended to the use of high-voltage switches with a limited operating voltage. A distinctive feature of the approach lies in using transfilters to equalize the instantaneous voltage values of the channels with the simultaneous rejecting action of higher harmonic components. The feasibility of the approach is shown using two options for generating the output voltage of a two-channel three-phase inverter: according to the algorithms of pulse-amplitude and pulse-width modulation. The adequacy of the structural-algorithmic synthesis results is confirmed by computer simulation in the OrCAD/PSpice environment [2]. The interrelations between the inverter input and output voltages necessary for its designing are determined. The operation principle of transfilters is considered, and their power-to-size ratio is estimated as a fraction of the load power (according to the fundamental harmonic). Recommendations for using a three-phase voltage inverter in a high-voltage traction frequency-controlled electric drive of railway rolling stock are given.

A CMOS Dual-Mode Brain-Computer Interface Chipset With 2-mV Precision Time-Based Charge Balancing and Stimulation-Side Artifact Suppression

This article presents a multipolar neural stimulation and mixed-signal neural data acquisition (DAQ) chipset for fully implantable bi-directional brain–computer interfaces (BD-BCIs). The stimulation system employs four 40 V compliant current-stimulators, each capable of sourcing/sinking a maximum 12.75 mA stimulation current, connected to 16 output channels through a high-voltage (HV) switch fabric. A novel time-based charge balancing (TBCB) technique is introduced to reduce the residual voltage on the electrode-electrolyte interface during the inter-pulse time interval, achieving 2 mV charge balancing precision. Additionally, an analytical study of the charge balancing accuracy for the proposed technique is provided. The recording system incorporates a dual-mode DAQ architecture that consists of a 32-element front-end array and a mixed-signal back-end including analog-to-digital converters (ADCs) for both training (i.e., full-band) and decoding (i.e., baseband) operations. Leveraging the flexibility of the multipolar operation, stimulation-side contour shaping (SSCS) artifact cancellation is adopted to significantly suppress stimulation artifacts by up to 45 dB. SSCS method prevents the recording front-ends from saturation and greatly relaxes the dynamic range requirement of the recording system, enabling a truly bi-directional operation. The prototype chipset is fabricated in an HV 180-nm CMOS process and demonstrates a significant performance improvement compared to the prior art.

A modified modular multilevel converter topology trigger generator for a pseudospark switch.

A novel trigger generator for operating a pseudospark switch has been developed based on a modified modular multilevel converter topology using insulated gate bipolar transistors. The trigger generator can be operated in either single- or high-repetition rate shot mode. It is characterized by a fast rise time and low temporal jitter between the output trigger pulses of less than 1ns. It produces pulses of 4.5kV and 1 µs duration into a 50 Ω load that can trigger a single pseudospark switch. By minimizing the high-voltage components, faster high-voltage switching takes place and the power density of the unit is increased. Furthermore, the overall volume of the trigger generator is reduced. Using this pseudospark trigger generator, it is possible to trigger single or multiple pseudospark gaps without the requirement to use a pulse shaping circuit.