A random switching method for HPWM full-bridge inverter

To overcome the problem of unequal switching loss in power switches, in conventional hybrid pulse width modulation (HPWM) full-bridge inverters, a random switching method for HPWM full-bridge inverters is proposed. The proposed method equalizes switching losses of the four switches, while also providing good output performance     

Switch energies of electronic and optical switches: a simplecomparative study

A comparison of the switch energies of electrically controlled optical absorption switches and electronic switches is performed. It is shown that in the investigated case with quantum box based absorption switches, the switch energies of the optical switches are generally orders of magnitude larger than those of the electronic switches for very high frequencies. Consequences on integration of optical devices as well as on the potential for photonic switching and processing are briefly discussed     

Novel zero-voltage and zero-current-switching full bridge PWMconverter using transformer auxiliary winding

A novel zero voltage and zero current switching (ZVZCS) full bridge (FB) pulse width modulation (PWM) converter is proposed to improve the demerits of the previously presented ZVZCS-FB-PWM converters, such as use of lossy components or additional active switches. A simple auxiliary circuit which includes neither lossy components nor active switches provides ZVZCS conditions to primary switches, ZVS for leading-leg switches and ZCS for lagging-leg switches. Many advantages including simple circuit topology, high efficiency, and low cost make the new converter attractive for high power (>2 kW) applications. The operation, analysis, features and design considerations are illustrated and verified on a 2.5 kW, 100 kHz insulated gate bipolar transistor (IGBT) based experimental circuit     

High-Voltage Solid State Switches for Grid Modulators of High-Power Microwave Devices

Microsecond high-voltage solid state switches based on metal–oxide–semiconductor field-effect transistors for application in pulse grid modulators of high-power microwave devices have been developed and investigated. Stable switching ranges of the switches based on unipolar and bipolar control circuits have been established. Combined switches with operating voltages of up to 10 kV and pulse currents of up to 12 A have been experimentally implemented.     

110kHz高重频多注速调管发射机

通过某110 kHz高功率多注速调管发射机的研制介绍了高重频发射机的设计要点,重点介绍了一种采用IGBT开关管串联组成的高重频高压固态浮动板调制器的设计,对调制器的电路组成和为实现高重频所采取的关键技术进行了简要的介绍,对发射机的主要组成、高压电源和撬棒保护电路等也进行了简要的介绍。试验结果表明,采用固态开关串联完全可取代传统的真空管开关,在高重频的大功率雷达发射机中稳定可靠工作。     

The new switching effect in liquid selenium

Liquid selenium shows above 720°C a reversible switching from higher to lower conductance effected by an electric field. Below 720°C liquid selenium switches first to higher and then to lower conductance. After switching to low conductance, a voltage controlled negative resistance is observed. By means of a single pulse technique the current oscillograms of the switchings (switching to high conductance, to low conductance and multi-switching) are investigated. The influence of magnetic field upon the switching (delay time and threshold voltage) is investigated. An electronic explanation for the switching and the influence of the magnetic field on it is given.     

Ultrafast switching dynamics of Mach-Zehnder interferometerswitches

We present results of cross-gain and cross-phase modulation experiments on InGaAsP-based semiconductor optical amplifiers and Mach-Zehnder interferometer (MZI) switches. For 150-fs input pulses, we observe strong spectral and pulse shape distortions of the signal pulse, especially in the pulse overlap regime. These pulse deteriorations are induced by subpicosecond gain and refractive index nonlinearities. In consequence, the ON-OFF ratio of the MZI switch is drastically reduced for subpicosecond switching windows. In the copropagation arrangement, the switching window with maximum transmission is shown to be limited to about 1.5 ps     

Survey of switching techniques in high-speed networks and their performance

One of the most promising approaches for high speed networks for integrated service applications is fast packet switching, or ATM (asynchronous transfer mode). ATM can be characterized by very high speed transmission links and simple, hard-wired protocols within a network. To match the transmission speed of the network links, and to minimize the overhead due to the processing of network protocols, the switching of cells is done in hardware switching fabrics in ATM networks. A number of designs have been proposed for implementing ATM switches. Although many differences exist among the proposals, the vast majority of them are based on self-routeing multistage interconnection networks. This is because of the desirable features of multi-stage interconnection networks such as self-routeing capability and suitability for VLSI implementation. Existing ATM switch architectures can be classified into two major classes: blocking switches, where blockings of cells may occur within a switch when more than one cell contends for the same internal link, and non-blocking switches, where no internal blocking occurs. A large number of techniques have also been proposed to improve the performance of blocking and non-blocking switches. In this paper, we present an extensive survey of the existing proposals for ATM switch architectures, focusing on their performance issues.     

一个快速高压固态开关的设计及实现

大多数固态功率开关中，开关速度会随着电源的增加而降低。基于这种原因，有很多方法在高功率下可获得合适速度。其方法之一是中压和额定电流大功率开关串联或并联的开关结构。这篇文章研究了不同型号的快速固态功率开关并选择IGBT作为开关单元。为了模拟，设计了IGBT的微观工作模型。最后，采用了8个IGBT串联的原型固态开关结构并且在7KV和600A下测试，其开通时间少于150纳秒。     

节能型谐振直流环节逆变器

为改善逆变器的运行效率,提出了一种节能型三相谐振直流环节软开关逆变电路,在直流环节增设了辅助电路.当主开关需要切换时,提前使辅助电路进入谐振状态,将直流环节电压变化到零,保证主开关完成零电压软切换,并且辅助开关也能完成软切换.通过控制辅助开关切换的间隔时间来调节直流环节电压保持为零的时间,使逆变器能根据需要来调整脉宽调制策略.详细说明了电路的工作过程.实验结果表明逆变器主开关和辅助开关能完成软切换.因此,该拓扑结构对于研发高性能谐振直流环节逆变器具有借鉴意义.     

为电流探头分析设计的60ns上升时间的1kA脉冲电流源

在电力电子应用方面，大电流和高带宽电流探头的运用是必须的，以便分析现代快速开关功率半导体器件的开关特性。目前普通的电流探头基本上可以达到每微秒10KA或更高。为了检测电流探头的可用性，象取样电阻、电流变换器或者Rogowski传感器，设计了电流源，它能产生以60纳秒上升的平顶为1KA脉冲。     

用布拉格相移光纤光栅实现光标记交换的方法

提出了用布拉格相移光纤光栅中相移来实现低功率的光标交换的新方法。设计了一个基于该方法的光标记交换实验。实验所用的布拉格光纤光栅是在通信用的标准光纤内刻写而成,通过强泵浦脉冲作用在低强度的探测信号上。光标记交换是基于交叉相位调制来完成的。     

Nanosecond Laser-Driven Semiconductor Switch for 70 GHz Microwave Radiation

We study a new type of semiconductor switches for microwave radiation driven by laser emission. The switches comprise a plate of plain semiconductor built in a hollow metallic waveguide resonator. The plate can be illuminated by laser emission changing the resonator properties due to photoconductivity and therefore switching between two stable states. A sample switch has been built and experimentally investigated, demonstrating nanosecond level of switching performance. The results of numerical simulation by the FDTD method are compared with the experimental data. Typical laser pulse energies sufficient for switching are from 1 nJ to 100 nJ, switched radiation frequency tuning range is about 10 % around 70 GHz. The switching operation was observed in wide range of the driving 100-femtosecond laser parameters - for pulse energy from 6 pJ to 250 μJ, and laser emission wavelength from 0.75 μm to 2 μm.     

Nonlinear pulse switching using cross-phase modulation and fiberBragg gratings

We propose and analyze a new all-optical nonlinear switch. The device is based on cross-phase modulation (XPM)-induced temporary frequency shift upon co-propagation of signal and control pulses with walkoff, and on the filtering effect of a fiber Bragg grating (FBG). Very high ON/OFF contrast with practically no pulse distortion can be achieved with moderate switching power. The new device possesses some important advantages over nonlinear optical-loop mirror switches     

The three-level ZVS-PWM DC-to-DC converter

A novel high-frequency DC-to-DC power converter for high voltage and high power is introduced which features zero voltage switching (ZVS), operation at constant frequency, regulation by pulse width modulation (PWM), and low RMS current stress upon power switches. Its greatest attribute, in comparison with the full-bridge (FB-ZVS-PWM) converter, is that the voltage across the switches is half of the input voltage, This property is achieved due to the use of a three-level leg in place of the conventional two-switch leg. Operation, analysis, design procedure and example, and simulation are presented. A prototype operating at 100 kHz, rated at 600 V input voltage, and 1.5 kW output power and 25 A output current has been fabricated and successfully tested in the laboratory. The measured efficiency at full load was 93%     

A wavelength-tunable duplex integrated light source for fastwavelength switching

A new monolithically integrated opto-electronic device has been developed for fast wavelength switching in photonic packet switching. The integrated device, called a tunable duplex integrated light source comprises two distributed Bragg reflector lasers (DBR-LDs), two electroabsorption optical switches, a Y-shaped waveguide coupler, an electroabsorption modulator, and two thermal drift compensators (TDCs). The tuning range of the DBR-LDs is 3 nm, and the wavelength switching time of the optical switches is estimated to be 60 ps including a 50 ps rise time for the electrical pulse generator. The wavelength of a 10 Gb/s NRZ-modulated optical signal is switched without bit loss. Thermal crosstalk between the DBR-LDs, and wavelength drift of the DBR-LDs, which is due to a thermal transient, are effectively suppressed by thermal-drift-compensation operation using the TDCs     

High-Frequency Waveform Generation Using Optoelectronic Switching in Silicon

Conversion of dc energy to RF pulses may be accomplished by fast optoelectronic switching in semiconductors. A particular device is described and demonstrated involving the simultaneous activation of an array of silicon switches by a laser pulse. The resultant traveling wave is a short RF pulse burst whose waveshape is determined by the static voltage profile established in the device. The possibility exists for generating megawatt-level pulses at frequencies extending into the higher microwave bands.     

单相全桥三电平节能逆变器

随着开关频率的提高,单相全桥逆变器处于硬开关切换时的开关损耗也会明显增大,将导致逆变器处于低效率运行.为解决这一问题,提出了一种单相全桥三电平节能逆变器.通过设置辅助换流电路,利用谐振使主开关并联的电容的电压下降到零,主开关可实现零电压切换,而且在换流过程中,两组双向辅助开关可分别实现零电压切换和零电流切换.分析了电路的工作状态,实验结果表明主开关和辅助开关都能实现软切换.因此该单相全桥三电平逆变器可实现高效率运行.     

微空心阴极放电试验用软开关电源的研究

微空心阴极放电（MHCD）是在普通空心阴极放电的基础上提出的一种高气压下亚毫米级微放电技术.将MHCD作为大体积辉光放电的外部电离源（即等离子体源）,可以解决高气压下大体积辉光放电不稳定的问题.在MHCD实验的基础上,研制出可对MHCD气体放电模式（连续/脉冲）和输出功率进行调控的开关电源.这种开关电源可以与单片机、微机等其他外部控制设备相连.该电源采用全桥软开关技术,串联谐振并联输出,4个MOSFET管为主控制元件,实现了高频工作,响应快速.脉冲模式工作时避免了开关管的硬开关,减小了高次谐波对电网干扰;无需镇流电阻也可实现气体稳定放电.     

Narrow Pulse Elimination PWM for Multilevel Digital Audio Power Amplifiers Using Two Cascaded H-Bridges as a Nine-Level Converter

This paper presents a methodology to reduce total harmonic distortion (THD) in digital audio power amplifiers, using two new approaches: 1) a multilevel converter made of two cascaded full-bridges, with suitable power supplies to operate as a nine-level hybrid type converter and 2) a new pulsewidth modulation (PWM) technique called narrow pulse elimination (NPE) PWM. The proposed nine-level converter uses only eight MOSFETs. Unlike conventional PWM, the NPE PWM does not generate excessively narrow pulses, so that power semiconductors nonideal delays and switching times are still negligible. Therefore, the nine-level output voltage THD, mostly introduced in the power stage, is strongly reduced. With the NPE technique, the resolution of the generated PWM is no longer limited by the switching speed of the output switches, but only by the frequency of digital processing circuit. Simulation and experimental results from a laboratory prototype are presented in order to show the effectiveness of the proposed approaches