采用ZVS-PWM三电平直流变换器的电力整流模块

介绍了一种采用移相控制零电压开关PWM三电平变换器的电力整流模块，讨论了主电路和控制与驱动电路的设计，并给出谐振电感的参数设计，和实验波形。     

移相控制ZVSPWM全桥变换器在中小功率电源中的应用

移相PWM控制方式是近年来在全桥变换器中广泛应用的一种软开关控制方式,它实际上是将谐振变换技术与PWM变换技术相结合的产物。通常情况下移相PWM控制方式应用于大功率的变换器中,在文中将移相PWM控制方式和同步整流技术相结合,在中小功率的应用中进行尝试。     

移相控制ZVC PWM DC／DC全桥变换器的设计

就谐振软开关技术在DC／DC变换器中广泛应用,介绍了一种移相控制ZVC PWM DC／DC全桥变换器的设计方法,其包括功率开关管参数选取、主变压器设计、换流电感设计、缓冲电容选择及参数验算等。     

移相全桥ZVS变换器的分析和设计

移相全桥零电压开关变换器是中大功率直直变换场合的理想拓扑之一,但其次级整流二极管反向恢复时,产生严重的寄生振荡,二极管上存在很高的尖峰电压。而文献1中的变换器通过增加一个谐振电感和两个二极管,不仅可以实现软开关,还可以消除次级整流二极管反向恢复引起的电压振荡。基于此变换器的工作原理,文中设计了一台500W移相控制零电压软开关电源,给出了主电路的设计过程和实验波形。     

基于UC3875控制的高频谐振逆变电路

提出了一种以MOSFET为功率开关器件谐振电容分压输出高频逆变电路,分析了UC3875芯片移相控制的外围电路。文中还给出了一个60kHz逆变电路的仿真和实验波形,实验证明采用UC3875移相调压控制谐振电容分压输出的逆变电路是可行的。     

基于ORCAD Pspice A／DV9的移相谐振控制器UC3875的仿真应用

简要描述了全桥软开关移相控制的原理，介绍了谐振控制器UC3875的电气特性。在此基础上，设计了一个基于ORCDADPspice A／DV9的UC3875的仿真电路，对电路进行了仿真分析并引入PI调节技术进行了参数优化。     

移相控制全桥ZVS-PWM变换器及其控制电路的分析与设计

介绍了移相控制零电压开关PWM变换器的工作原理,分析了主电路实现零电压开关过程的条件、副边占空比丢失的原因以及工程解决策略,给出1kw电源的设计方法及主要参数的确定,讨论了相移脉冲宽度调制谐振控制器(UC3875)的工作原理和应用中要注意的若干问题,最后给出了实验结果和主要波形。     

电力操作电源主电路参数设计

本文简单分析了2.2KW电力系统用直流操作电源移相全桥软开关拓扑结构,设计和选择了主电路的滤波电容和电感等元件,制作了软开关主电路的主要部件,包括高频变压器和谐振电感;根据设计的开关电源实际特点,选择了主功率管和次级整流二极管。     

基于软开关技术移相全桥变换器的仿真分析

本文首先在硬开关与软开关的对比分析中提出软开关技术,介绍了移相全桥零电压PWM软开关电路的组成及其优点,对选定的拓扑结构主电路工作原理进行了详细的分析,详细地阐述了移相全桥软开关电路超前臂、滞后臂的不同工作状态,及超前桥臂和滞后桥臂的谐振过程。在对软开关逆变器工作过程及模型研究的基础上,建立了基于saber软件的仿真模型,仿真结果验证该方法的有效性,为逆变系统的软、硬开关的研究和设计参数的验证带来极大的方便。     

电力操作电源主电路参数设计

简单分析了2．2 kW的电力系统用直流操作电源移相全桥软开关拓扑结构,设计和选择了主电路的各元件参数,制作了软开关主要部件高频变压器、谐振电感；根据研制的开关电源实际特点,选择了功率管和次级整流二极管,最后利用实验来验证设计的正确性。     

移相谐振PWM控制器UC3875在开关电源中的应用

开关损耗是开关电源高频化的主要障碍之一,开关管共同导通而留的死区时间,限制了开关电源工作频率的提高,而移相谐振PWM技术正是利用死区时间,通过谐振腔使开关管输出电容上的电压迅速放电,从而实现零电压或零电流开关,减少开关损耗和降低噪声干扰。文章介绍了移相谐振PWM控制器UC3875的工作原理及应用。     

考虑数字控制的开关电源系统仿真

数字控制是开关电源的发展趋势，考虑数字控制开关电源系统仿真成为目前理论分析必须解决的问题。文中以工程实际电镀电源系统的研制为例，在Matlab与Simulink工具中提出了数字PI控制器的实现方法，利用S-Function实现了脉冲移相信号输出，完成了对移相全桥控制电镀电源系统的仿真。结果表明，它与实际结果十分吻合，可以很好地用于指导数字控制式电镀电源的研制。从而对一般数字控制式开关电源的分析具有借鉴意义。     

浅谈几种谐振变换器的控制方法

阐述了谐振变换器的变频、移相、自持振荡、自持振荡移相、最优轨迹等五种控制方法的实现原理,从其暂态响应、频率控制范围、软开关性能三个主要方面进行了对比研究,并做了仿真验证。     

电动汽车镍氢充电器的设计

介绍了一种2.4kW用于电动汽车的高频软开关镍氢充电器,该充电器主充电电路采用零电压零电流全桥PWM逆变器,移相芯片UCC3895作为调节器,单片机ATMEGA8作为辅助控制器,实现对镍氢电池的智能三段式充电。     

电动汽车镍氢充电器的设计

介绍了一种2.4kW用于电动汽车的高频软开关镍氢充电器,该充电器主充电电路采用零电压零电流全桥PWM逆变器,移相芯片UCC3895作为调节器,单片机ATMEGA8作为辅助控制器,实现对镍氢电池的智能三段式充电。     

All-optical switching in a laterally coupled microring resonator by carrier injection

We demonstrate all-optical switching in a laterally coupled GaAs-AlGaAs microring resonator by carriers injections. The ring waveguide is optically pumped just above its bandgap energy, which results in a temporal tuning of the microring resonant wavelengths by the refractive index change due to the induced carriers. A switching window of 20 ps could be obtained and is only limited by the carrier recombination time. A switching energy of a few tens of picojoules per pulse is used and has resulted in a 1.2-nm wavelength shift of the microring resonance.     

Microwave Frequency Translator

A stepped phase-shift approach, employing semiconductor switching techniques in waveguide, is used to achieve frequency translation at microwave frequencies. Stepped phase shift is employed to approximate a continuous or ideal sawtooth phase shift. It has been shown by Fourier analysis that three is the minimum number of phase steps required to achieve frequency translation with suppression of the carrier and first symmetrical sideband. A tunable device using microwave switching diodes in a single port Y junction is described. The diodes progressively switch three lenths of waveguide into the circuit establishing three phase steps. A ferrite circulator is used to create a two port device and a modulator supplies proper diode biases and switching logic. Carrier suppression of greater than 30 dB and first symmetrical sideband suppression of greater than 20 dB was observed; other sideband amplitudes are predictable. A conversion efficiency of -6 dB including the circulator loss was measured and the bandwidth for 20 dB carrier suppression varies from almost one per cent to three per cent, depending on other suppression criteria.     

A wide range analog MMIC attenuator with integral 180° phaseshifter

A circuit topology is discussed for achieving a wide-range analog attenuator in MMIC form using enhancement mode FET's by combining it with a 90° phase shift network. By switching the phase shift network between a 90° phase lead high-pass structure and a 90° phase lag low-pass structure, a dual-purpose circuit is formed comprising both a variable attenuation and 180° phase shift function. The approach requires only a single control voltage for the attenuator and achieves an attenuation range of over 30 dB in L-band with less than 10° of phase imbalance over the range. In the low-loss state, the phase shifter achieves a 10° phase balance over a 250 MHz bandwidth with less than 0.3 dB of amplitude imbalance     

Optimal loop length of a nonlinear optical loop mirror in switchingsolitons

The optimal loop length of a nonlinear optical loop mirror (NOLM) for switching solitons was investigated numerically for the case where the wavelengths of the control pulse and signal soliton straddle the dispersion zero. In our analysis, the Raman effect is also included because the wavelength difference between the control and signal pulses is within the Raman gainband. It was found that the control pulse not only imposes phase shift on the copropagating signal, but also transfers part of its energy to the signal. Furthermore, the broadening of the control pulse due to the combined effect of self-phase modulation and group velocity dispersion increases the switching power of the control pulse significantly. The broadening of the control pulse also introduces more uniform phase shift to the signal, thus resulting in a higher switching efficiency. Finally, our results show that the pulse distortion is minimal if a loop length equivalent to one soliton period is employed     

Frequency response and phase-shift nonlinearity of a cylindricalPVF2-film-based fiber-optic phase modulator

A cylindrical coil configuration for a polyvinylidene-fluoride (PVF₂)-film-based fiber-optic phase modulator is studied, focusing on the frequency response and the nonlinearity of the phase shift at the resonant frequency. This configuration, hitherto used for PVF₂ film modulators, offers resonance at well-defined, controllable, and higher frequencies than possible for the flat-strip configuration. Two versions of this configuration that achieve selective mode suppression or enhancement and hence provide a choice of the resonance frequency at which a large phase shift occurs are presented. It is shown that a coil version in which the fiber loops are bonded strongly to each other leads to large reduction in the phase shift. A comparative study of the existing piezoelectric fiber-optic phase modulator designs is also presented