查询词典 frequency converter

Based on analysis to the principle of back-to-back converter for direct-driven variable speed constout frequency WECS,phase lock loop based sensorless control strategy was adopted to determine the speed and phase angle of PMSG,and its work principle and realization method are analyzed in detail.

在分析直驱型变速恒频风电系统背靠背变流器工作原理的基础上，采用锁相环无速度传感器控制策略对永磁同步发电机的速度和相位进行观测，对其工作原理和实现方法进行了分析。

In this paper, a current control mathematical model is established with fixed switching frequency for three-phase pulse width modulated converter.

建立了三相电压型PWM整流器电流控制数学模型，输入电流在静止坐标系下实现了固定开关频率的解耦控制。

Based on these, the single phase converter system is studied in detail, including the selection of the main circuit scheme, the formation of Sine-wave Pulse- width Modulation signal, the design of the drive and protection circuit of IGBT, and the design of high frequency transformer. Finally, the simulation software is employed to test the effect. And the result is satisfactory.

在此基础上，本文主要对电能质量控制稳定器所需的DC/AC控制电源进行了详细研究，包括主电路方案的选择、SPWM波的生成、IGBT的驱动和保护电路、高频变压器的设计以及闭环电压控制原理，最后进行了输出电压的计算机仿真分析，结果是令人满意的。

This thesis firstly discusses some research focus of high-frequency power supply and variable circuit topologies are compared here. Then it emphasizes the operating principle of phase shift full bridge converter and realization of soft switching techniques.

首先简单讨论了目前高频开关电源的研究热点，对各种变换电路拓扑结构形式进行了分析比较，然后重点分析了移相全桥变换器的工作原理和软开关技术的实现。

Proposed DSP engine consists of rectangular to polar converter and digital phase modulator that are designed based on the COordinate Rational DIgital Computer and Direct Digital Frequency Synthesizer algorithm respectively.

所提出来的数位讯号处理引擎包含了座标转换器和数位相位调变器，两者分别是利用数位座标旋转器以及数位频率合成器来实现。

Double-frequency three-phase bridge converter in three phase power factor correction, three-phase active power filter are studied theoretically and experimentally.

本部分研究内容提出的双频变换器理论，申请人和导师合作分别于2006、2005年申请成功国家自然科学基金项目&高效率高性能双频变换器理论及其控制&(50677071)、教育部博士点基金项目&双频变换器理论及其应用&(200611012)和重庆市自然科学重点基金项目&新型高效电能变换技术理论及控制研究&(2005BA6017)，发表相关论文9篇。

In order to reduce the capacity of the pulse converter, the paper try to choose family as high-frequency pulse output.

为了减少脉动转换器的容量，本文选择试用高频脉冲族作为输出。

Based on one-cycle control having such merits as anti-perturbation of source, fast dynamic response, robustness, constant frequency, but when converter works in light load its power factor becomes very poor. The modified OCC was proposed, adopting feed-forward compensation control improves influence of power factor at light load, further study adopting independence saw tooth wave completely eliminate influence of power factor at light load.

基于单周期控制有源前端变换器具有抗电源扰动能力强、动态响应快、鲁棒性强、恒频控制等优点，但在轻载时变换器的功率因数变差，提出了改进OCC策略，采用前馈补偿控制改善轻载时对功率因数的影响，进一步研究采用独立的锯齿波电路完全消除轻载时对功率因数的影响，建立改进OCCAFE变换器的数学模型。

Its final target is to fully digitize the analogue receiver. The all digital receiver not just means digitizing every unit of the analogue receiver, but is a new receiver architecture. The two outstanding characters of this new architecture is: 1 It uses a high stable oscillator to generate a fixed frequency source. And both the sample signal and the local carrier required are obtained from it. 2 Once the received signal has been sampled by a high speed A/D converter, some digital signal processing algorithms will be used to realize all further processes, such as digital down-converting, match filtering, symbol timing, channel equalizing, carrier synchronizing, demodulating and decoding.

全数字接收机并不是简单地将传统的模拟接收机中所有的部件数字化的结果，而是一种全新的接收机体系结构，这种新的体系结构具有两个最为突出的特点：1）采用高稳定度晶体振荡器产生一个固定的本地频率源，接收机中所需的采样时钟信号和本地载波均从这一固定频率源得到；2）接收信号一旦经过高速模数转换后，余下的工作如频率变换、匹配滤波、定时同步、信道均衡、载波同步、符号解调、判决与译码等全部由数字信号处理算法来实现。

A new type high efficiency synchronous step-up DC/DC converter for hand-held device is designed in this thesis. It works in the PFM mode, and its switching frequency can up to 500 KHz. It offers a built-in synchronous rectifier that reduces size and cost by eliminating the need for an external Schottky diode and improves overall efficiency by minimizing losses.

本文设计了一种用于移动电子设备的高效同步整流的DC/DC升压芯片，该芯片采用PFM调制方式，工作频率最高可达500 KHz，内部集成功率管作为同步整流管，代替传统的肖特基二极管，导通电阻仅有0.4？

Since historical times,England ,where the early inhabitants were Celts, has been conquered three times .

从有历史以来，英国，在此地早期居住的是凯尔特人，已经被征服了三次。

Bluetooth OBEX File Transfer Enables the sending and receiving of files on your phone via Bluetooth.

蓝牙OBEX文件移动允许经过蓝牙传送和接受文件。。。。