查询词典 pulse-code modulation

In this thesis, the heterojunction with intrinsic hydrogenated amorphous silicon thin layer ( heterojunction with intrinsic thin layer: HIT) solar cells are investigated. The solar cell structure of p/i/n are fabricated. The substrate is a typical 4-inch n-type wafer with (100) crystal orientation, 1~10 ohm-cm and about 525 μm thickness. The p and i a-Si:H layers are deposited by a 13.56 MHz plasma enhanced chemical vapor deposition. The i a-Si:H layers are especially deposited by pulse-wave modulation plasma technique with fixed plasma turn-off time toff = 10 ms and changed plasma turn-on time ton= 10 to 40 ms to selectively control the different silicon to hydrogen bonding configurations. The effect of various Si:H bonds on the performance of HIT solar cells are explored.

中文摘要本论文针对异质接面薄本质层(heterojunction with intrinsic thin layer： HIT)太阳电池进行研究，采用一般典型四英吋晶向为(100，厚度约为525 μm，电阻率约为 1~10 ohm-cmn型矽晶圆为基板，制作p/i/n太阳电池，p及i层薄膜以13.56 MHz电浆加强化学气相沈积，i层并采用脉波调变电浆技术，在固定电浆关闭时间toff = 10 ms及改变电浆开启时间由ton = 10 ms 至40 ms条件下制作具有不同矽氢键结微结构的氢化非晶矽薄膜以探讨不同矽氢键结对太阳电池性能的影响。

An effective method for improvement transient response in pulse-width modulation current source converter is studied.

给出了单相和三相变频器的实验结果，与采用其他方法的变频器相比，该方法的变频器电源电流的暂态响应得到了有效改善。

Buck and Boost topology switching power conversion circuits as the core of this system, ultra low power MSP430F1222 microcontroller-based controller, microcontroller produced by the PWM pulse width modulation signals, respectively, two-way control switch voltage conversion circuit the turn-on and turn-off in order to achieve the above two kinds of topology switching power conversion circuit, and then to draw power from the flow of electrical energy has been filled into the rechargeable battery, and using microcontroller A / D input voltage implementation of the monitoring, according to the input voltage switching buck - circuit at a lower cost to achieve a highly efficient energy transfer, and the circuit is simple, the parameter to determine easy, self-low power consumption,to achieve full-featured.

本系统以Buck降压和Boost升压拓扑结构开关电源变换电路为核心，以超低功耗单片机MSP430F1222为主控器，由单片机产生PWM脉宽调制信号，分别控制两路电压变换电路中开关管的导通与关断从而实现以上两种拓扑结构开关电源变换电路，进而从一直流电源中吸取电能充入可充电电池，并利用单片机A/D对输入电压实施监测，根据输入电压切换升降压电路，以较低的成本实现了高效率的电能转移，并且电路简单、参数确定容易，自身功耗低，实现功能完整。

A DC-to-DC converter includes a pulse width modulation circuit cooperating with at least one power switch for supplying power from a source to a load over a range between a lower limit and an upper limit to thereby control an output voltage for the load.

一种直流-直流转换器，包括一个与至少一个的电源开关协作，以在一个上限和下限的范围内由电源向负载供电，从而为负载控制输出电压的脉宽调制电路。

The control mode has developed from early U\f control mode to vec to r control technology and pulse width modulation.

控制方式也从早期的电压；频率控制方式发展到向量控制技术和冲宽度调制技术。

Three-phase Asynchronous Motor;Digital Signal Processor;Intelligent Power Module;Vector Control;Space Vector Pulse Width Modulation

三相异步电动机；数字信号处理器；智能功率模块；矢量控制；电压空间矢量脉宽调制

The principle of Space Vector Pulse Width Modulation control of three phase inverter is presented.

文中叙述了三相逆变器空间电压矢量控制的基本原理。

This paper introduces the basic principle of pulse width modulation based on voltage space vectors and realization algorithm.

本文介绍了SVPWM的基本原理及其实现算法。

Based on this model, interaction between the parallel grid-connected inverters is analyzed and the influence on circulating current when it is adopted zero vector with space vector pulse width modulation is also analysed.

在这模型的基础上，分析并网逆变器并联运行时的相互影响；分析了并网逆变器采用间矢量脉宽调制算法时零矢量对环流的影响。

Secondly, the vector control theory,the kinematics model and the sinusoidal space vector Pulse-Width-Modulation control technology were analyzed dividually, and then the mathematic simulation model of the servo system of PMSLM was built.

其次，综合运用电机控制理论和计算机仿真技术，分别对永磁同步直线电机的矢量控制原理、运动力学模型以及电压空间矢量脉宽调制技术进行分析，搭建了永磁同步直线电机伺服控制系统的数学模型。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。