电路

The methods to achieving balanced current are presented and simulated in this paper. Thirdly, the snubbers are designed to compress the switching voltage transient. When IGBT is abruptly turned off, trapped energy in the circuit stray inductance is dissipated in IGBT, causing a voltage overshoot and damaging IGBT.

针对IGBT工作过程中出现的电压尖峰、电流尖峰和大的开关损耗问题，本文首先从理论上详细分析了IGBT逆变桥缓冲电路的工作原理，推导出缓冲电路各元件的参数计算公式，讨论了缓冲电路各元件参数对关断电压波形的影响并进行了仿真分析。

Some circuits use resonant, quasi-resonant, and/or multi-resonant techniques. However, voltage or current stresses in these converters are higher and require the devices of higher VA rating. Some circuits use passive snubbers or active clamp techniques. However these converters become more complicate. Phase-shift ZVS technique has been used in bidirectional DC/DC converters since it can realize ZVS for all switches without auxiliary switches.

谐振、准谐振或多谐振技术方案，变换器的电压电流应力较高，变频控制增加了滤波器设计的难度；能量缓冲吸收电路或有源钳位电路方案，由于需要增加多个额外辅助元件，增加了变换器的复杂性；全桥相移技术方案，由于主电路无需增加额外元件，只需利用相移控制，即可实现软开关，因此引起关注。

First the conception of switched—current technology is introduced in this paper,and then an analysis of errors in SI—memory cell is given.The resolvents which aimed at the errors mentioned above are provided.At last,a new improved circuit is given.

首先介绍了SI技术，然后以SI电路基本单元为例，分析了SI电路存在的各种误差，并针对这些误差提出了解决方法；最后提出了一种新的改进电路。

In view of these problems,an intrinsically safe pilot circuit for underground motor intelligent protective systems based on single chip microcomputer is given according to the design specifications of intrinsically safe circuits and the requirements of microcomputer control systems.

针对这些问题按照本安电路设计规范和微机控制系统的要求，设计了一个适合矿井电动机微机保护系统用的本安先导电路，对所设计的电路进行了试验研究并将其应用于矿用隔爆型电磁起动器。

This article angle has analyzed the higher professional technical education from CBE/DACUM "the electrical control technology" the curriculum ability localization, according to the higher professional technical education "the electrical control technology" the curriculum ability localization, point out the insufficiency and flaw existed in commonly used control electric appliance choice, electrical pilot wire road map, electricity control system installment, wiring craft, electrical control line fault diagnosis system approach, new starting velocity modulation equipment and control circuit, control circuit and main circuit aspect and so on.

摘要本文从CBE/DACUM角度分析了高职&电气控制技术&课程的能力定位，根据高职&电气控制技术&课程的能力定位，指出了现行高职&电气控制技术&教材在常用控制电器选择、电气控制线路图、电气控制系统安装、接线工艺、电气控制线路故障诊断的系统方法、新型起动调速设备及控制电路、控制电路与主电路的连接等方面存在的不足和缺陷。

There are three parts in this system such as high-power RF Auto-follow circuit, radio tube RF high-handed monofier, and monitor and show circuit.

该系统主要包括大功率射频激励电路、电子管射频高压振荡电路及监控与显示电路3部分。

This design uses AT89C51 SCM chip controls the charging process, achieving A/D convert and show circuit. The battery voltage information can be detected by the external circuit to choose the correct charge mode, realizing the intelligent conversion mode of the trickle charge, the constant current charging, the constant voltage charging and the float charge.

采用AT89C51单片机芯片作为充电过程的控制芯片进行电路设计，实现A/D转换和显示电路，并根据外部电路检测到的电池电压信息选择正确的充电模式，实现在涓流、恒流、恒压及浮充电模式之间的智能转换。

This paper presented the main functions and characteristics of Multisim8.0, and the main qualities of high frequency tunable amplifier such as voltage gain, transmission bands and selectivity were studied using simulation analysis and testing technologies of Multisim 8.0. The results are visual and precise, and prove the theory very well. This software has powerful simulation and analysis function, by which the analysis and design of high frequency circuit are not only more precise and credible, but also more closed to the real circuit running status.

本文介绍了Multisim8.0仿真软件的主要功能及特点，并结合该软件对高频单调谐放大电路的电压增益、通频带、选择性等主要质量指标进行了测试与仿真分析，结果直观、精确，很好地验证了理论，表明该软件有强大的仿真和分析功能，在实现高频电路分析和设计方面不仅高效、可靠，而且具有逼近真实电路的效果。

In the last new years , as the demands of wireless communication system grows rapidly , the bands of microwave frequency had been saturated with various communication applications . To achieve wider spectrum for high-speed and high-capacity transmission , bands of millimeter-wave frequency are the solution of this problem . The advantage of MMW wireless communication systems is wider bandwidth comparing with microwave communication systems . To utilize the spectrum efficiently , many methods of complexly digital modulation is proposed . The more complex modulation , the higher linearity is required , and more various phase of signals are required to accomplish process of modulation . Therefore high-linearity and quadrature-phase modulator and demodulator are the emphasis of this thesis . For high level of integration , high performance and low cost , this chip is fabricated by the complementary oxide semi-conductor 0.13um process . A compact size of direct down-conversion and direct up conversion circuits will be presented in this thesis .

近年来随著无线通讯产业的蓬勃发展，微波频带已经趋近於饱和，为了追求更宽的频谱来达到更快传输速率及高资料容量的传输，宽频的毫米波频段提供了解决此问题的途径，毫米波无线通讯系统提供了相对於微波通讯系统宽频的优点，且为了更有效的使用频谱，各种不同且复杂的数位调变方式及方法被发表出来，越复杂的调变方式其所需的线性度越高，且需要更多不同的相位讯号来完成调变的过程，因此高线性度及四相位的调变及解调器将是此篇论文的研究重点，为了达到高整合性，高效能，及低成本的电路设计，我门利用互补式金氧半导体制程来完成此电路设计，因此一小面积的直接降频(Direct down-conversion)及直接升频(direct up-conversion)电路将在文中介绍。

A redundant control circuit comprises a pair of heater circuits for heating a hot melt adhesive hose assembly to a predetermined temperature level, and a pair of temperature sensors which are used to sense the temperature of the hot melt adhesive hose assembly and to control energization of the heater circuits in order to maintain the desired temperature level.

一种冗余控制电路，包括用于将热熔胶软管组件加热到预定温度水平的一对加热器电路，和用于感应热熔胶软管组件的温度并控制加热器电路的电压以便维持期望的温度水平的一对温度传感器。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。