电压

The fundamental law that is applied in this method is Kirchhoff's first law, which states that the algebraic sum of the voltage around a closed loop is 0, or, in any closed loop, the sum of the voltage rises must equal the sumof the voltage drop.

该方法所使用的一个基本定律是基尔霍夫第一定律，该定律表述为：沿着一个封闭回路的电压代数和为0，或者：沿着一个封闭的回路，电压降之和等于电压升之和。

The fundamental law that is applied in this method is Kirchhoff's first law, which states that the algebraic sum of the voltage around a closed loop is 0, or, in any closed loop, the sum of the voltage rises must equal the sum of the voltage drop.

该方法所使用的一个基本定律是基尔霍夫第一定律，该定律表述为：沿着一个封闭回路的电压代数和为 0，或者：沿着一个封闭的回路，电压降之和等于电压升之和。

Trickle and floating charge can make each single cell battery receiving electricity constant, ensure batteries capacity resuming maximum, settle the disproportion phenomenon of single cell battery, avoid the overvoltage charge danger of the power voltage change and the end of battery charge and extend the operational life of battery.

61548；完善的充电特性：采用恒流技术，充电初期电流恒定，使每节电池都能较快地充分地充满电，充电效率高，电池温升小；在充电电压达到上限电压时自动切换到恒压限流充电，有效的提高了蓄电池的容量转换效率；涓流浮充使各单体电池均衡受电，保证电池容量得以最大限度恢复，有效解决单体电压不均衡现象，避免了市电电压的变化和蓄电池充电的末期造成的蓄电池过压充电的危险，大大延长了蓄电池的使用寿命。

The article presents the developing condition of PWM and SVPWM first.Then the theory of SVPWM is discussed in detail.The SVPWM is based on the thought of magnetic chain tracking.It makes the ideal magnetic chain circle of three-phased sysmmetry electric motor supplied by three-phased sysmmetry sine wave voltage for basis,uses the practical magnetic chain vector formed by the different switch modes of three-phased inverter to track the basic magnetic chain circle.During the course of tracking,the inverter changes the switch modes properly to form the PWM waves.Then the modulation wave of SVPWM is analyzed in detail.The modulation wave of SVPWM is implicit,but the analogous modulation wave in A-B-C axis needs to be calculated in order to expose the internal relation of SVPWM and SPWM.That is to show the implicit modulation wave of SVPWM. SVPWM actually is a transformed SPWM ruly sampled by the modulation wave which is injected by the zero prefaces based on space vectors.

本文首先对脉宽调制技术的发展现状进行了综述，在此基础上分析了电压空间矢量脉宽调制技术的发展现状；接着对空间电压矢量脉宽调制技术的基本原理进行了详细的分析和推导，SVPWM是基于磁链追踪的思想，它以三相对称正弦波电压供电下三相对称电动机定子理想磁链圆为基准，由三相逆变器不同开关模式下所形成的实际磁链矢量来追踪基准磁链圆的，在追踪的过程中，逆变器的开关模式作适当的切换，从而形成PWM波；然后详细分析了电压空间矢量脉宽调制技术的调制波，虽然SVPWM法的调制波是隐含的，但是为了揭示SVPWM法与SPWM法的内在联系，需要求出SVPWM在A-B-C坐标系上的等效调制波，也就是将SVPWM的隐含调制波显化；SVPWM实质是一种基于空间矢量在三相正弦波中注入了零序分量的调制波进行规则采样的一种变形SPWM。

This system to dc voltage source as the core, mainly AT89S52 SCM, through the keyboard controller to install dc power supply output voltage, setting stepping class can reach.01v output voltage, the range of 0-9.9 V, the maximum current 330mA for, and can show the actual pipe by digital output voltage value s.

摘 要：本系统以直流电压源为核心，AT89S52单片机为主控制器，通过键盘来设置直流电源的输出电压，设置步进等级可达0.1V，输出电压范围为0—9.9V，最大电流为330mA，并可由液晶屏显示实际输出电压值。系统有过流保护电路，当输出电流过大时功率管自动截至，而且有红色指示灯发出警报。

Abstract摘要:This system to dc voltage source as the core, mainly AT89S52 SCM, through the keyboard controller to install dc power supply output voltage, setting stepping class can reach.01v output voltage, the range of 0-9.9 V, the maximum current 330mA for, and can show the actual pipe by digital output voltage values.

论文摘要摘要：本系统以直流电压源为核心，AT89S52单片机为主控制器，通过键盘来设置直流电源的输出电压，设置步进等级可达0.1V，输出电压范围为0—9.9V，最大电流为330mA，并可由液晶屏显示实际输出电压值。系统有过流保护电路，当输出电流过大时功率管自动截至，而且有红色指示灯发出警报。

Keywords: regulated power supply of direct current; single2ch ip m icrocomputer, digital control Abstract:This system to dc voltage source as the core, mainly AT89S52 SCM, through the keyboard controller to install dc power supply output voltage, setting stepping class can reach.01v output voltage, the range of 0-9.9 V, the maximum current 330mA for, and can show the actual pipe by digital output voltage values.

数控直流稳压电源论文关键词：论文关键词：直流稳压电源单片机数字控制论文摘要：论文摘要：本系统以直流电压源为核心，AT89S52 单片机为主控制器，通过键盘来设置直流电源的输出电压，设置步进等级可达 0.1V，输出电压范围为 0—9.9V，最大电流为 330mA，并可由液晶屏显示实际输出电压值。

This system to dc voltage source as the core, mainly AT89S52 SCM, through the keyboard controller to install dc power supply output voltage, setting stepping class can reach.01v output voltage, the range of 0-9.9 V, the maximum current 330mA for, and can show the actual pipe by digital output voltage values.

论文摘要：本系统以直流电压源为核心，AT89S52单片机为主控制器，通过键盘来设置直流电源的输出电压，设置步进等级可达0.1V，输出电压范围为0—9.9V，最大电流为330mA，并可由液晶屏显示实际输出电压值。系统有过流保护电路，当输出电流过大时功率管自动截至，而且有红色指示灯发出警报。

This system to dc voltage source as the core, mainly AT89S52 SCM, through the keyboard controller to install dc power supply output voltage, setting stepping class can reach.01v output voltage, the range of 0-9.9 V, the maximum current 330mA for, and can show the actual pipe by digital output voltage values.

本系统以直流电压源为核心，AT89S52单片机为主控制器，通过键盘来设置直流电源的输出电压，设置步进等级可达0.1V，输出电压范围为0—9.9V，最大电流为330mA，并可由液晶屏显示实际输出电压值。系统有过流保护电路，当输出电流过大时功率管自动截至，而且有红色指示灯发出警报。

The influences of seasonal factor on the safety of grounding system were analyzed in numerical method.

因为网孔电压是发变电站内最严重的接触电压，在本文的分析中都是采用网孔电压来代替接触电压［1］。

Shop assistant: Please check at the door.

店员：请您到门口柜台交费。

In the end, transportation of PAHs in the environmental matrix was preliminarily investigated and discussed according to PAHs data of soils and sediments from a certain region in Shanghai. The result indicated that there are two or more pathways on PAHs transportation in the environmental matrix.

最后，对上海特定地区内PAHs在环境介质中的迁移径途进行了分析讨论，结果表明上海市土壤和沉积物等环境介质中PAHs的迁移存在多种途径。