1 THz Modulation in InGaAsP Multiple Quantum Wells for 40 Gb/s Applications

The terahertz (THz) rate modulation of quantum well (QW) electrooptic modulators necessitates a new way of thinking about how the modulation field modulates light; specifically, an incident narrow-band (with respect to the modulation frequency) signal once modulated acquires frequency components separated from the input signal center frequency by multiples of the modulation frequency. In this paper, we discuss the design of the QWs comprising the modulator to maximize the output at such THz sidebands of the incident optical frequency in InGaAsP QW based devices. We present a theoretical treatment of the case in which the THz modulation frequency is out of resonance between any exci- tonic levels near those exploited for the optical modulation, thus enabling an adiabatic treatment of the modulated optical susceptibility. We show that THz sideband conversion efficiencies of ~1% may be possible.     

Optical Wavelength Conversion by Cross-Phase Modulation of Data Signals up to 640 Gb/s

In this paper, all-optical wavelength conversion by cross-phase modulation in a highly nonlinear fiber is investigated. Regenerative properties of the wavelength converter are demonstrated, and the effect of adding Raman gain to enhance the performance of the wavelength converter is shown. The wavelength conversion scheme is demonstrated at the record-high bit rate of 640 Gb/s.     

Digital Control Technologies for DC/DC Switching Converters

An overview of recent advances in digital control of low-to medium-power DC/DC switching converters is presented.Traditionally,analog electronics methods have dominated in controlling such DC/DC converters.However,with the steadily decreasing cost of ICs, the feasibility of digitally controlled DC/DC switching converters has increased sig-nificantly.This paper oudines a sample of digital solutions for DC/DC switching converters to enhance the performance of DC/DC switching converters.Furthermore,latest research activities pertaining to applications for steady-state and dy-namic performance improvement,such as efficiency optimization,controller auto tuning,and capacitor charge balance control, is discussed.These applications demonstrate the significant advantages and potentials of digital control.     

开关DC/DC变换器多级脉冲调节控制方法

提出了一种新型的开关DC/DC变换器控制方法--多级脉冲调节(MPA)控制方法.MPA控制器在每个开关周期起始时刻根据变换器的输出电压误差,在强弱等级不同的多级脉冲中选取一个作为该周期的有效控制信号.文中分析和讨论了MPA控制原理,研究了工作于电流断续模式的MPA控制Buck变换器的工作过程和小信号模型.分析结果表明,MPA控制具有优异的鲁棒性、瞬态特性和稳态特性.仿真和实验结果验证了理论分析的正确性.     

准滑模控制开关DC-DC变换器分析

准滑模控制的滑模系数和边界层的选取因缺乏明确的关系式而难以确定,该文以相变量系统模型为基础,详细分析了准滑模控制方法的特性和在Buck变换器控制中的应用;研究了准滑模控制的边界层、滑模系数、准滑动模态区相互之间的定量数学关系,所获得的研究结果可以指导我们有效的选取滑模系数和边界层厚度。计算机仿真和实验结果表明准滑模控制器可以获得更加平滑的占空比,有利于减小输出电压的纹波,抑制系统抖振。     

Monolithic Wavelength Converters for High-Speed Packet-Switched Optical Networks

This paper describes the design and demonstration of advanced 40-Gb/s return-to-zero (RZ) tunable all-optical wavelength converter technologies for use in packet-switched optical networks. The device designs are based on monolithic integration of a delayed interference Mach-Zehnder interferometer (MZI) semiconductor optical amplifier (SOA) wavelength converter with a sampled-grating distributed Bragg reflector tunable laser and an on-chip waveguide delay. Experimental results are presented demonstrating error-free wavelength conversion with 1-dB power penalty at 40-Gb/s data rates. By incorporating label modulation functionality on-chip along with a fast tunable 40-Gb/s wavelength converter, fully monolithic packet-forwarding chips are realized that are capable of simultaneous error-free wavelength conversion of 40-Gb/s payloads, remodulation of 10-Gb/s packet headers, and data routing through fast wavelength switching     

基于FPGA的DC/DC开关变换器的数字控制器

在DC/DC开关变换器的数字控制器设计中,数字信号处理器(Digital Signal Processor,简称DSP)和现场可编程门阵列(Field Programmable Gate Arrays,简称FPGA)是两种主要的数字器件.在此,结合实际的数字控制DC/DC开关变换器,研究了在FPGA平台上实现DC/DC开关变换器的数字控制器,同时介绍了数字控制器中使用的各功能模块及其整个系统的时序.实验系统的测试结果证明了将FPGA用于DC/DC开关变换器的数字控制器是可行的.     

All-Optical Tb/S 3R Wavelength Conversion Using Dispersion-Managed Light Bullets

We present an all-optical wavelength converter that can operate at a very-high-switching rate with simultaneous reshaping, retiming, and regenerating (3R) capabilities based on nonlinear interactions between dispersion-managed (DM) (3+1)-dimensional optical solitons (light bullets). Numerical simulations have been performed to demonstrate the generation of the DM light bullets and the spatial dragging interaction between solitons with different colors for ultrafast wavelength conversion application. This all-optical 3R wavelength converter has a very compact size of 100 mum times 100 mum times 1 mm, and is able to convert information at an ultrahigh speed of over 1 Tb/s between wavelength channels of 50 nm apart. Such an ultrafast all-optical wavelength converter has potential applications in future optical time-division multiplexing (OTDM) and wavelength-division multiplexing (WDM) combined communication networks that require both the ultrafast switching speed due to the large bandwidth within each wavelength channel and the wavelength conversion function for exchanging information between different wavelength bands or spatial switching within the same wavelength bands.     

双级PFC AC/DC变流器的设计及电路实验

系统并深入地分析了单级和双级功率因数校正(Power Factor Correction,简称PFC)AC/DC变流器的性能特征,指出了它们各自存在的优缺点.在此基础上,结合软开关技术特点,提出了一种基于集成化设计的双级PFC AC/DC开关变流器电路.该电路克服了传统单级和双级变流器存在的不足,具有高效、高功率因数和低成本的特点.此外,还给出了该电路的实验结果.     

Low-Crosstalk 103 Channel$,times,$10 Gb/s (1.03 Tb/s) Wavelength Conversion With a Quasi-Phase-Matched LiNbO$_3$Waveguide

We propose a low-crosstalk multichannel wavelength conversion scheme based on a parametric process. Simultaneous wavelength conversion of 25 GHz spaced 103 channel$,times,$10 Gb/s (1.03 Tb/s) wavelength-division multiplexing signals with an 8- and 4-nm guard band is successfully demonstrated by using a quasi-phase-matched lithium niobate waveguide. The method is evaluated both theoretically and experimentally.     

开关DC/DC变换器的统一离散模型

为了确切地描述DC/DC变换器的系统特性,指导变换器的控制策略设计,文中利用状态转移矩阵,建立了基于电感电流连续和不连续两种运行模式的Boost变换器统一离散模型.给出了根据系统当前状态及控制策略,计算每个开关周期中功率开关关断后电感电流持续时间的方法,给出了变换器运行模式的判断条件,确定了模型的系数矩阵.与实验结果进行比较,验证了统一离散模型的有效性.     

开关变换器的双频率PWM调制技术研究

提出了开关变换器的双频率PWM调制(Bi-frequency Pulse Width Modulation,简称BF-PWM)技术,分析了其工作原理和调制特性,利用PSPICE对双频率PWM调制Buck变换器进行了仿真,并与传统PWM调制Buck变换器的仿真结果进行了比较.仿真和实验结果表明,双频率PWM调制方法具有比传统PWM调制方法优异的抑制电磁干扰(Electro-magnetic Interference,简称EMl)性能.     

开关DC-DC变换器双频率脉冲序列调制技术

提出一种新颖的开关DC-DC变换器调制方法:双频率脉冲序列调制(bi-frequency pulse train modulation,BF-PTM)方法。BF-PTM通过对两组频率不同、但导通时间相同的控制脉冲进行调制,实现开关变换器输出电压的调节。BF-PTM适用于各种开关变换器拓扑。以电感电流断续模式(discontinuous conduction mode,DCM)Buck变换器为例,分析BF-PTM开关变换器的工作原理及控制特性,并进行相应的仿真及实验研究。研究结果表明,BF-PTM控制开关变换器具有优于PWM开关变换器的瞬态响应和电磁干扰特性。     

电流型双频率脉冲序列调制开关变换器

提出了开关变换器电流型双频率脉冲序列调制BF-PTM方法,研究了电流型BF-PTM的控制策略。电流型BF-PTM控制技术无需误差放大器及其相应的补偿网络,具有结构简单,稳定性好,动态响应速度快,电磁干扰噪声水平低,易于实现等优点;此外,通过将电感电流引入到控制环,易于实现电流型BF-PTM控制开关变换器的过电流保护和多变换器的并联均流控制。以电感电流断续导电模式Buck变换器为例,对电流型BF-PTM控制开关变换器进行了研究,仿真及实验结果表明,电流型BF-PTM比传统的电流型PWM具有更快的动态响应速度和更低的电磁干扰噪声。     

DC/DC变换器及谐振软开关技术

对几类最具代表性的软开关技术从理论到电路拓扑进行了论述，并指出各自的优缺点及发展趋势。     

电力电子变换器机内辅助开关电源

反激变换器具有电路拓扑简洁、输入输出电气隔离、电压升/降范围宽、易于多路输出等优点,因而是机内辅助开关电源理想的电路拓扑。     

恒定导通时间双频率控制开关变换器

本文提出并研究了一种新型开关变换器控制技术——恒定导通时间双频率(COT-BF)控制技术。COT-BF控制技术利用两组预先设定的具有相同导通时间但不同开关频率的控制脉冲,实现对开关变换器输出电压的调整。COT-BF控制器实现简单,无需误差放大器及其相应的补偿网络。本文以电感电流断续导电模式(DCM)Buck变换器为例,研究了COT-BF控制开关变换器的工作原理及控制策略,并进行了实验研究。实验研究结果表明,COT-BF控制DCM Buck变换器具有比传统电压型脉冲宽度调制开关变换器更快的瞬态响应速度和更低的电磁干扰。     

开关变换器传导干扰抑制策略综述

开关变换器广泛应用于可再生能源并网、电机驱动系统、消费电子供电等领域,其电磁干扰问题日益突出,因此该问题的解决非常重要.该文总结开关变换器传导干扰抑制策略及其最新进展,重点说明这些策略的基本原理、研究现状和作用特点.总结的策略主要包括滤波、电桥平衡、反相补偿、改进脉宽调制、改进功率器件/模块封装、优化电路板设计、改善开...     

三电平变流器低开关损耗调制算法研究

随着工业应用对大功率电力电子设备性能要求的提高,变流设备开关频率升高导致开关损耗增大。研究了三电平变流器低开关损耗调制算法,通过预先设定合理的脉冲序列并根据序列对中点电位的影响将其分类为P型和N型序列,根据中点电位偏移情况控制两类序列的柔和切换,从而实现中点电位平衡和降低开关损耗的目标。预设的脉冲序列在一个采样周期只有4次开关动作,可减少开关损耗约1/3。另一方面,在部分扇区内,通过选择冗余序列实现大电流箝位以进一步减小开关损耗。实验结果证明了算法对中点电位平衡控制及其减少开关损耗的有效性。     

一种有源交错并联Boost软开关电路

本文提出了一种新型的有源交错并联的Boost软开关电路。在boost主开关两端并联一个有源辅助开关和关断缓冲吸收电容组成的有源缓冲吸收支路。使用该拓扑结构，Boost的主开关管可以实现零电流导通和零电压关断，二极管的反向恢复电流带来的能量损耗能够大大削减。并且，在整个开关周期期间，附加的辅助开关管都是零电压开关。在理论分析的基础上，试制了1台1.2kW实验样机