High-voltage Switch Research Articles

Toxic Gas Eliminator from Print Ink by Applied High Frequency High Ripple Pulse Corona

This paper presents the design and development of toxic gas eliminator from print ink using high frequency high ripple pulse corona technique for decrease VOCs gas in the suction gas of printing ink using high voltage AC switched mode power supply. Using mini inverter principle and control of the switching by IC No.MB3579. The inverter is designed to operate at 10 kHz to 20 kHz through a high voltage switching transformer at output voltage of 1.5 kV, and at the input voltage of 18 VAC 50 Hz, By adapting the non-uniform electric field to the electrode design 3 tubes, one - hour operating yields the ozone gas (O3) generating capacity of 6.3 ppm enables decrease VOCs gas as well.

Ultrahigh-Voltage Switch for Bidirectional DC–DC Converter Driving Dielectric Elastomer Actuator

Specific applications, such as dielectric elastomer actuators (DEAs) or electroactive polymers, require to switch voltage levels exceeding the ratings of existing semiconductor devices. In low-power application, reversible flyback is widely used to supply DEAs. Lowering the parallel parasitic capacitance of the high-voltage switch is important to improve the energy transfer, while it becomes mandatory to increase the output voltage of flyback above 2.5 kV. In this article, a pulsed transformer gate driver (PTGD) is used to drive series-connected MOSFET and, therefore, push the limits from 4.5 to 16 kV. At these high-voltage levels, the structure reveals a drastic voltage unbalance related to the transformer interwinding parasitic capacitance. The compensation method proposed to achieve voltage balance only adds few passive components and reduces significantly the additional parallel capacitance of the switch compared to common load side voltage balancing methods. Finally, and as proof of concept, a half-bridge bidirectional converter was designed from this switch technology and drove an actual DEA at 16 kV.

Analysis of Internal Heat Transfer Characteristics of High voltage Switch Cubicle Heating Fault

The high-voltage Switch Cubicle is an important equipment in the power system, which undertakes the connection function. There are many kinds of components and parts in the cabinet, and there are many connection contacts. It is easy to be affected by the surrounding environment, aging and corrosion and other internal and external factors. Some components and parts in bad working conditions or in abnormal conditions, especially the dynamic and static contacts of components and parts are prone to heating failure. If the heating parts cannot be identified, maintained and disposed in time, the failure probability of the switch cabinet will be greatly increased, the destructive force and influence caused by the failure will be amplified, and finally the stability of the whole power system will be affected, reliability. Based on the structure of the switch cabinet and the characteristics of the heating fault, combined with the theory of heat transfer, this paper analyzes the internal heat transfer characteristics of the heating fault of the switch cabinet, and uses the fluent software to establish a mathematical model for simulation verification, so as to provide a theoretical basis for the diagnosis of the internal heating fault of the cabinet.

Design and Implementation of Electro-Optic 2×2 Switch and Optical Gates using MZI

AbstractMZI switches are well-known devices for high speed communication applications. A lot of researchers have designed MZI switches by using lithium niobate and potassium niobate material. But the major problem of using these type of material includes high insertion losses and required high switching voltage. So, in this research paper we have designed a 2×2 electro-optic switch using optical waveguide designed with Titanium (Ti) diffused in Strontium barium niobate (SBNO3) material which can operate at wavelength of 1.3 um. Results show that the proposed structure gives better output in terms of extinction ratio (=29.9 db) as well as for insertion losses (≤0.018). Further, we have designed various optical gates i. e. XNOR, XOR and AND optical gates and their performance is also evaluated by varying electrode voltages. It is inferred from the results that the proposed model gives better results even in terms of output power which can be used for commercial purpose.

Electromagnetic interference characteristics during switching operation in power distribution network

The disturbance problem caused by the transient electromagnetic field during high-voltage switching operation is the most typical. Electromagnetic interference can be coupled to the secondary circuit in a conductive and radiating manner, then, affects the reliability of the secondary-side circuit. The key to the simulation calculation of the operating switch overvoltage is the judgment and simulation of its opening and closing conditions. The arc current zero-crossing judgment signal, the arc extinguishing and reignition judgment signals are fused, and a control signal is recursively obtained for switching operation. By analyzing the transient process during switch operation, a simplified model for isolating and closing the no-load bus, an overvoltage calculation model, and a fast transient model for overvoltage time-frequency signals are established. The characteristics of the transient electromagnetic field generated when the no-load bus and the circuit breaker of the disconnector are charged to the no-load transformer are simulated. The mechanism of fast transient pulse group generated by switching operation is obtained. The maximum overvoltage amplitude generated during the disconnector’s switching, and the no-load bus is obtained by simulation. Comparing with the measured data, the laws of electromagnetic interference characteristics during switching operation in power distribution network are verified.

A Family of Zero-Voltage-Switched Resonant Converters: Derivation, Operation, and Design

Soft switching based on resonant operation, through mitigating switching loss and alleviating electromagnetic interference, is essential to high-frequency operation to achieve high power density. To overcome the obstacles of high switch voltage stress and ease the contradiction between voltage stress and conduction loss for traditional single-switch resonant converters, a family of zero-voltage-switched (ZVS) isolated resonant converters is proposed which utilizes a novel resonant switch. The converters enable parasitic components, including transformer leakage inductance, switch output capacitance, and diode junction capacitance to act as a part of resonant components, which facilitates ZVS and zero-current-switching operation and pushes up switching frequency. The specific derivation of the topologies is expounded, and one of the proposed converters is taken for example to perform in-depth analysis, whose mode analysis, operation principles, and parameter design method are minutely presented. Synchronous rectification is employed to further improve efficiency. A prototype was built in the laboratory and the experimental results validate the theoretical analysis well.

Experimental Studies of the Corrosion Resistance for Q235 and Q235NHin the Outdoor High-voltage Disconnector

Aiming at the corrosion failure question of the outdoor high-voltage isolation switch, accelerated corrosion testsusing 5% (mass fraction) NaCl salt spray for materials of Q235 and Q235NH were carried out. By means of the controlled trials method, samples were divided into two groups, and each group contains four specimens. After that, neutral-salt-spray corrosion tests with 60h, 100h, 130h, and 160h were conducted. Finally, the rust layer was observed by a microscope, and the corrosion rate was calculated according to the weight loss method. Experimental results indicated that the rust layer in Q235NH was more compact after being corroded. As a result, it provide more protection for the substrate.

A Novel Modified Switched Inductor Boost Converter With Reduced Switch Voltage Stress

Recently, switched inductor (SI) and switched capacitor techniques in dc-dc converter are recommended to achieve high voltage by using the principle of parallel charging and series discharging of reactive elements. It is noteworthy that four diodes, one high-voltage rating switch, and two inductors are required to design classical SI boost converter (SIBC). Moreover, in classical SIBC, the switch voltage stress is equal to the output voltage. In this article, modified SIBC (mSIBC) is proposed with reduced voltage stress across active switches. The proposed mSIBC configuration in this article is transformerless and simply derived by replacing the one diode of the classical SI structure with an active switch. As a result, mSIBC required low-voltage rating active switches, since the total output voltage is shared into two active switches. Moreover, the proposed mSIBC is low in cost, provides higher efficiency, and requires the same number of components compared with the classical SIBC. The continuous conduction mode and discontinuous conduction mode analysis, the effect of nonidealities on voltage gain, design methodology, and comparison are presented in detail. The operation and performance of the designed 500-W mSIBC are experimentally validated under different perturbations.

Dynamic Switching of SiC Power MOSFETs Based on Analytical Subcircuit Model

Compared to silicon counterparts, silicon carbide (SiC) power mosfet s have lower on -state resistance and faster switching speed, which in turn makes them better candidates for high-voltage power switching applications. This creates a growing need to develop device models for such SiC power devices. The models that are currently being used are mostly physics-based models, which require all the physical parameters of the device and are not so suitable for real time hardware in loop simulations. In this article, we show a subcircuit model based on the analytical study using nonlinear curve fitting method for modeling of dynamic switching behavior. Using a 1.2 kV, 17 A mosfet as a testbed, this subcircuit model is validated by implementing the model into Synopsys Saber in comparison with the measured dc characteristics, the Saber mosfet Tool model, and the manufacturer's model. The switching behavior of the device at 800 V/17 A and 800 V/5.5 A based on the subcircuit model were also compared and validated with experimental measurements, the Saber mosfet model, and manufacturer's model. Excellent agreements were achieved on both dc characteristics and switching behaviors. On the LTspice platform, the computation time of the analytical subcircuit model is 4.5 times faster than the manufacturer's model. This subcircuit model is adoptable and suitable for real time hardware in loop simulations and power converter designs .

Resistive switching behaviors and mechanisms of HfS2 film memory devices studied by experiments and density functional theory calculations

Energy band diagrams are widely utilized to explain the switching mechanism of resistance random access memory (RRAM). However, a precise and quantitative band theory is still lacking in this field. Although HfS2 has good applications in many fields because of its good electrical and optical properties, its applications in RRAM have seldom been reported. In this work, the exfoliated nanosheets of HfS2 were utilized to fabricate memory devices with a structure of Pt/Al/HfS2/p+-Si, which show typical bipolar resistive switching behavior with high switching voltage and a small ratio of high and low resistive states (R-ratio). According to the density functional theory (DFT) calculation results of energy band diagrams, instead of conductive filament formation in other resistive switching materials, the doping of sulfur vacancy (VS) of 3.8% is already enough to change the whole HfS2 layer from the semiconductor to the metal. The transition is caused by the change in the VS doping concentration from low to high, which is the result of the generation and movement of VS under an electric field. The DFT also calculated that HfS2 devices utilizing Indium Tin Oxide as the bottom electrode can show bipolar resistive switching behavior with lower switching voltage and a higher R-ratio than those utilizing p+-Si, which is confirmed by the experimental results. The DFT calculation can be utilized for both explaining the switching mechanism and designing the device structure to optimize the switching characteristics.

Construction and test of an ion-gate with high-voltage switch system for single-reflection time of flight measurement

An ion gate and its high-voltage pulse switch system are constructed to produce a few nanosecond pulse beam so that the beam can be used for the time of flight (TOF) measurement. The maximum gating voltages are set to be ±1 kV to deflect away ion beams of intermediate heavy nuclei such as 133Cs when the gate is closed. The ion gate was designed by calculating deflection angles analytically and was checked numerically, which were in agreement. On the other hand, the switch system uses a Behlke switch, solid-state high voltage device, for pulse gating and its circuit was designed utilizing an equivalent circuit of the gate. Simulation by LTspice showed that a 10 ns pulse with a peak voltage of 2 kV can be produced if the capacitance of the gate is less than 50 nF. The ion gate was first tested inside the TOF system to ensure that a Cs1+ beam can be turned on and off in terms of beam arriving at a Faraday cup. The switch was then tested in connection with the gate, and we found that the pulse can be produced and its peak can be controlled by adjusting the capacitance of connection cables so far as its width is kept.

Continuous temporal ion detection combined with time-gated imaging: Normalization over a large dynamic range

Imaging micro-channel plate (MCP) detectors are a common tool for chemical physics studies used to image a single ion mass species in a time-of-flight (TOF) spectrum. Temporal selection of the mass to be imaged is traditionally implemented by gating the voltage across the MCP stack, however this leads to the loss of all information about other species in the mass spectrum. Here we show that by gating the phosphor voltage instead, as has been demonstrated by Zajfman et al. (1995) among others, we gain the capability of measuring multiple masses in TOF while retaining the ability to image a single desired species. In our precision spectroscopy experiment, we image the spatial distribution of Hf+ photodissociation fragments, while its more plentiful HfF+ precursor, which arrives at a later time, can also be detected in TOF. This enables the shot by shot normalization of technical noise associated with the precursor production. Since the scheme alters only the configuration of the high-voltage switch, it can be readily implemented in most existing gated MCP setups, allowing the full TOF information to be harvested. Combining the imaging and TOF data in a single shot, we can detect species with substantially different abundances.

Spatiotemporal modes of fast avalanche switching of high-voltage layered semiconductor structures: From subnano to picosecond range

The effect of delayed impact ionization breakdown initiated in high-voltage Si or GaAs p+nn+ diode by a steep voltage ramp leads to 100 ps avalanche transient from blocking to conducting state. Here, we demonstrate that qualitatively different inner mechanisms—or spatiotemporal modes—can be responsible for superfast high-voltage avalanche switching. The well-known mechanism based on TRApped Plasma Avalanche Triggered Transit (TRAPATT)-like ionizing front passage is compared with three novel spatiotemporal switching scenarios. The first of these novel modes corresponds to a new type of ionizing front travelling across the structure faster than the saturated drift velocity. Another corresponds to the quasiuniform avalanche breakdown of the whole n base. The last one—the “back-stroke” mode—takes place when switching occurs only in the part of the device cross section. For these novel modes, the calculated switching time (tens of picoseconds) is several times smaller than for well-known TRAPATT-like front (∼100 ps). We analyze all four spatiotemporal modes in their connection with the device structural parameters. By means of numerical simulations, we demonstrate that varying only one parameter of a p+nn+ structure—the n base dopant concentration—it is possible to completely change the inner dynamics. Our analysis reveals that subnanosecond—100 ps or less—switching time may be determined either by the ionizing front passage time or by the internal “discharge” time of the device via generated electron–hole plasma.

High Step-Up DC–DC Converter With Zero Voltage Switching and Low Input Current Ripple

A high step-up dc-dc converter is proposed in this article. With magnetic-coupling-based voltage multiplier technique, the proposed converter achieves high voltage gain and low switch voltage stress. Also, due to a boost inductor at the input, continuous input current is obtained, which is beneficial for battery, fuel cell, and photovoltaic applications. Moreover, zero voltage switching of the mosfets is achieved, leading to low switching losses. Furthermore, zero dc bias of the coupled inductor is realized, resulting in small magnetic size and low core losses. The operation principles, performance analysis, and design considerations of the proposed converter are discussed. A prototype with 40-V input and 400-V output has been developed to verify the theoretical analysis.

A High-Voltage Solid-State Switch Based on Submodule Topology of SiC MOSFETs for J-TEXT Tokamak

Due to safety and reliability concerns, high-voltage solid-state switch is required for electron cyclotron resonance heating system on J-TEXT Tokamak. It cuts off the power supply within a little time usually in microseconds, when a fault occurs. At present, wide-bandgap semiconductors based on silicon carbide (SiC) show superior material properties enabling potential power device operation at higher voltage, current, and switching speeds than current silicon (Si) semiconductors. SiC metal-oxide-semiconductor field-effect transistors (MOSFETs) are considered to be a better solution for the basic component of the switch than Si insulated gate bipolar transistors (IGBTs). To solve the problem of voltage balancing in series-connected MOSFETs, a submodule with four, 1.7 kV/40 A rated MOSFETs in series has been developed and experimentally tested. A voltage-clamped snubber circuit is designed to control the overvoltage of each MOSFET. The turn-off performance of the proposed circuit and traditional circuit has been compared by simulation, and the submodule has also been evaluated in a dual-pulse test. Finally, the solid-state switch with 16 submodules in series has been tested by a dummy load. The experimental results show that switch can operate successfully, and the switching performance satisfies the anticipated demand.

A Hybrid String-Inverter/Rectifier Soft-Switched Bidirectional DC/DC Converter

In this article, a new bidirectional dc/dc converter topology based on a hybrid string-inverter/rectifier structure with an isolated CLLC resonant circuit is presented for energy storage applications. In this topology, a novel inverter/rectifier leg is presented that enables this circuit to operate in rectifying mode with much lower voltage ripple compared to the standard four-switch string rectifier circuit with the same capacitive filter. Compared to the dual-active-bridge circuit structure, the proposed inverter/rectifier leg is able to reduce the number of high-voltage switches required. A CLLC resonant circuit is employed to step-up/down the dc voltage levels. The operating principles of the proposed converter are discussed in this article. Silicon Carbide switches are used in both legs of the proposed converter, with zero-voltage switching turn- on and zero-current switching (ZCS) turn- off realized for all switches, whereas ZCS turn- on and off are achieved for all diodes. Simulation and experimental results are provided on a 1-kW, 100-kHz, 400-V/700-V converter system to highlight the merits of the proposed converter. Experimental results demonstrated that an efficiency of close to 97% is achieved in the proposed converter in both boost mode and buck mode at the full-load condition.

A New Single-Phase AC Voltage Converter With Voltage Buck Characteristics for Grid Voltage Compensation

Voltage sags and swells are the major problems of the power distribution system that arise due to uneven distribution of the single-phase and nonlinear loads. They severely degrade the power quality and may cause the failure of the equipment at the user's side. The voltage sag and swell issues are compensated by operating the AC voltage controllers with bipolar voltage gain characteristics. In these converters, high switching voltage and current, and a large number of switching devices are the main issues that cause unwanted power losses and result in reduced efficiency of the system. High voltage stresses may cause device failure due to the increase in dv/dt rating. The large count of switching devices results in high cost and high conversion losses. So here, we propose a novel AC converter with fewer switching devices that reduces switching voltage and current to have low conversion losses. The amplitude of the output is governed through the direct PWM control (DPWM) of one switch that controls the switching state of the other switch indirectly called indirect PWM control switch (IDPWM). The detailed analysis of the proposed converter is carried out to compare its performance with the existing converters. MATLAB/Simulink environment-based simulation results are proved through the experimental results obtained by developing a hardware prototype.

Research on the online temperature measuring device in outdoor high-voltage isolation Switch

In view of the frequent overheat or even fusion accidents of outdoor high-voltage isolation switch contacts in operation, and they are serious threats to its equipment security and the reliability of power network. To mitigate and reduce the influence effected by abnormal heat of isolating switch contacts, this paper describes the structure of the temperature measuring device, the temperature chip, the wireless communication mode. Moreover, the on-line temperature measuring device’s characteristic of structure and function was summarized. The experimental dada shows that the device has large measuring range, high precision, high reliability and availability. In order to understand the operation status of outdoor high-voltage isolators, the device can realize real-time measurement the temperature without the technical personnel at the scene.

A BMC Analog and Digital PHY for USB Type-C Power Delivery

A Type-C biphase mark code (BMC) transceiver in 0.14- <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 technology is presented. The analog PHY in combination with digital PHY supports BMC data for USB power delivery (PD) negotiations through a Type-C cable. It compensates for signal-level loss and duty cycle distortion due to ground shifting at both ends of a Type-C cable. Analog receiver includes a BMC squelch detector decision-making comparators and a duty cycle correction circuit. Analog transmitter includes a slew rate control circuit, level shifter, and linear line driver. Digital PHY makes more corrections on duty cycle in the receiver side, recovers bits and symbols from the asynchronous serial data, and sends BMC coded data to the transmitter. The connector-facing high-voltage pins to which an analog transceiver is connected are protected against the high-voltage surge. Analog receiver consumes 0.2-mA current under 3-V supply and analog transmitter consumes 1.7-mA current to drive a 1-nF and serial 50- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> loads. The total area of receiver and transmitter with all supporting circuits and high-voltage switches is 0.4 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The implemented transceiver is compliant with USB PD and Type-C standards with respect to all required parameters.

Dual-Stage Control Structure for Multilevel Voltage Source Inverters

This work proposes an alternative for total harmonic distortion (THD) attenuation in power inverters by combining two different circuit stages. The Macro stage comprises of a Neutral-Point-Clamped (NPC) multilevel inverter operating in high voltage and low switching frequency. The Micro stage is a two-level three-phase inverter, which is faster and more accurate due to its higher frequency and limited voltage. In this dual-stage approach, the opposite characteristics of the converters lead the Micro stage to correct the distortions of the Macro. It is possible to work with small values of filtering components, lower than the ones needed in a one-stage approach. This way, the presented proposal aims to reduce the physical size of the converter and its costs. The NPC inverter works in open loop with its switching signals generated by optimized pulse patterns (OPP). For correct THD filtering, a resonant control strategy with a Notch filter is designed in the frequency domain, as well as a feedforward structure designed in time domain. Simulation results show that the proposed system keeps voltage THD in acceptable levels for IEEE Standards.