查询词典 power frequency

Later, it makes some comparison with four kinds of modulation technique, and finally, it implements the three-level PWM switching power amplifier with the PWM technique. The power of the amplifier is 2kVA, and the frequency bandwidth is 10～3kHz. In the thesis, the author designs and makes the hardwares of the switching power amplifier. The hardwares contain power inverter rank circuit, control system circuit based on DSP, drive and isolation circuit, and protective circuit. The thesis also analyses the potential safety problems and put forward some solutions for the problems. Furthermore, the thesis accomplishes the software design of the control system, and successfully debugs it. The methods of designing higher power ampilfier are also discussed in the thesis. It analyses the feasibility of the methods, outlines the way of how to design higher power switching power amplifier, and does some experiments with the method of switches-parallelling.

根据电动振动试验系统对开关功放的要求，提出了以电感电流瞬时值控制技术为基础的三电平脉宽调制开关功放的设计方案，并通过系统仿真进行了原理性论证；然后设计并制作了开关功放的硬件，包括功率转换电路，基于DSP的控制电路，驱动、隔离电路以及保护电路；针对开关功放数学模型不易得出的特点，细致分析了模糊自适应PID控制方法，在此基础上编写了控制程序；研制出一台功率为2kVA，通频带为10～3kHz的三电平脉宽调制开关功放；论文中还探讨了实现大功率开关功放的方法，分析了各种方法的可行性，给出了实现大功率开关功放的思路，并进行了并联开关管实现大功率开关功放的实验。

Vertically put the KAS detector on the upper part of the transmitter cover, turn EAS detector power supply switch on, EAS detector displays radio frequency output center frequency is: 8.2±0.05MHz; Adjust R15 (counterclockwise decrease, clockwise increase) can change radio frequency output center frequency.

把 EAS 检测仪垂直放置于发射机壳上部，按动 EAS 检测仪电源开关， EAS 检测仪显示射频输出中心频率为：8.2±0.05MHz ；调节 R15（反时针减少、顺时针增大）可改变射频输出中心频率。

Some possible applications of wide-area measurement system in power system are gathered up, including applications in static analysis, recording dynamic procedures of the whole power network and post-contingency analysis, identifying and calibrating the dynamic model of power system, transient stability prediction and control, voltage and frequency stability monitoring and control, analyzing and damping the low frequency oscillation, global feedback control, fault location and parameter measurement o...

综述了广域测量系统(Wide-Area Measurement System，WAMS)在电力系统稳态分析、全网动态过程记录和事后分析、电力系统动态模型辨识和模型校正、暂态稳定预测及控制、电压和频率稳定监视及控制、低频振荡分析及抑制、全局反馈控制、故障定位及线路参数测量等方面的应用。通过这些应用可以看到，WAMS给电力系统分析与控制提供了新的视角和解决方法，值得深入研究。

ABSTRACT:The half-power bandwidth method is the commonly used method at home and abroad, the authors discover that factors, such as the sampling frequency, the frequency resolution, the ratio of the sampling frequency to the signal frequency, the analyzed width and the damping ratio, make the estimated damping ratio fluctuate vastly. Mostly the result is incredible except for some conditions, the error is sometime amazing, which is not acceptable.

半功率带宽法是国内外常用的测试阻尼的方法，笔者发现半功率带宽法由于受到信号处理中的①采样频率SF②频率分辨率△f③采样频率与信号频率之比K ④采样分析的长度T和⑤阻尼比D的大小等因素的影响使得测得的阻尼比值波动很大，除少数状态是可信的外，多数状态是不稳定的，有时误差惊人，得到的测试数据不能使用，易导致错误的结论。

They are advocates of green environmental protection energy-saving power supply, has been formed are: crystal-like medium, high, ultra-high frequency induction heating machine, high frequency quenching machine, high-frequency annealing machine, IF forging furnace, medium frequency melting furnace, high-frequency brazing welding machine, such as a series of high-tech products.

他们正在倡导绿色环保节能电源，目前已形成有：晶体式的中、高、超高频感应加热机，高频淬火机床，高频退火机，中频锻造炉，中频熔炼炉，高频钎焊机等一系列的高新技术产品。

It adopts the single chip computer control calculation meritorious service capacity, and parameters such as real power, reactive power, meritorious service rate element, tension fundamental harmonic virtual value and tension harmonious wave virtual value and so on these are separation to the calculation branch to the measurement that on the basis of the scattered integration formula in immediate future scattered Fourier transformation, the exchange basseted on to power system parameter sampling idea was achieved to adjust all the journey moreover the frequency alternating current frequency and the tension virtual value as well as the electric current virtual value in the way of software .

它采用单片机的控制运算功能，根据离散积分公式即离散傅立叶变换，基于对电力系统参数进行采样的思想，实现同时对一路工频交流电的频率、电压有效值、电流有效值的测量，用软件计算分析出有功功率、无功功率、功率因素、电压基波有效值、电压谐波有效值等参数。

It adopts the single chip computer control calculation meritorious service capacity, and parameters such as real power, reactive power, meritorious service rate element, tension fundamental harmonic virtual value and tension harmonious wave virtual value and so on these are separation to the calculation branch to the measurement that on the basis of the scattered integration formula in immediate future scattered Fourier transformation, the exchange basseted on to power system parameter sampling idea was achieved to adjust all the journey moreover the workmans frequency alternating current frequency and the tension virtual value as well as the electric current virtual value in the way of software .

它采用单片机的控制运算功能，根据离散积分公式即离散傅立叶变换，基于对电力系统参数进行交流采样的思想，实现同时对一路工频交流电的频率、电压有效值、电流有效值的测量，用软件计算分析出有功功率、无功功率、功率因素、电压基波有效值、电压谐波有效值等参数。

The main products TQSW no local place-frequency electrical impulse voltage testing transformer test sets of series resonant frequency generator unit test transformer dry-type high-voltage testing transformer the ball-gap discharge frequency divider DC High-frequency DC generator, generator, inverter-current multi-function grounding impedance test system-current generator (up-flow device) performance of an integrated test bed Transformer Partial Discharge Detector mechanical properties of high-voltage switches Vacuum Tester Tester Tester Loop Resistance transformer capacity Tester-Load Switching Test Transformer tumor resistance measurement Transformer turns ratio tester tester MOA group tester insulating oil dielectric strength tester transformer loss parameter Intelligent Tester transformer loss-line parameter tester frequency interference dielectric loss dielectric loss tester anti-interference relay tester Ground Yin Xiaxian conduction tester cable fault tester tester tester generator rotor impedance large Grounding Resistance Tester Tester transformer features an integrated micro-moisture meter aperture automatic flash point tester Automatic Closed flash point detector vacuum oil filter boots pressure test device (automatic, semi-automatic) nuclear phase Instrument Series wireless digital core Instrument security tools relative to the mechanical properties testing machine clamp grounding resistance of grounding resistance measuring instrument digital megger digital high-voltage insulation resistance tester and a scalable high-altitude test tools, digital dual-phase volt-ampere facade sequence table clamp Three-phase Power Parameters Tester Calibrator lightning strike counter dedicated test wire, clamping insulation boards, pipe, cable tray mats polyimide film conductor line busbar electric appliances

扬州市苏博电气有限公司扬州市苏博电气有限公司主要产品有TQSW无局部放电工频试验变压器冲击电压发生器变频串联谐振试验成套装置试验变压器干式试验变压器高压分压器放电球隙中频直流发生器高频直流发生器变频大电流多功能接地阻抗测试系统大电流发生器变压器性能综合测试台局部放电检测仪高压开关机械特性测试仪真空度测试仪回路电阻测试仪变压器容量测试仪变压器有载开关测试仪变压器肿瘤电阻测试仪变压器变比组别测试仪氧化锌避雷器测试仪绝缘油介电强度测试仪变压器损耗参数智能测试仪变压器损耗线路参数综合测试仪变频抗干扰介质损耗测试仪抗干扰介质损耗测试仪继电保护测试仪接地引下线导通测试仪电缆故障测试仪发电机转子交流阻抗测试仪大型地网接地电阻测试仪互感器特性综合测试仪微量水分测定仪开口闪点全自动测定仪闭口闪点全自动测定仪真空滤油机绝缘靴耐压试验装置核相仪系列无线数字核相仪安全工具力学性能试验机钳形接地电阻仪接地电阻测量仪数字兆欧表数字高压绝缘电阻测试仪可伸缩高空测试工具数字双钳相位伏安表相序表三相电力参数测试仪雷击计数器校验仪专用测试导线，钳绝缘板，管，垫聚酰亚胺薄膜电缆桥架滑触线母线槽电热电器

This series of instruments for low-voltage, medium voltage, high-voltage switchgear and distribution systems, central station monitoring system, generator set systems, building automation systems, energy management system, such as factories, able to measure three-phase three-wire, three-phase four-wire system current, voltage, active power, reactive power, apparent power, active power, reactive power, power factor, frequency, voltage triangular openings, the largest open-shaped voltage power parameters, at the same time with a remote, remote control function.

该系列 仪表适用于低压、中压、高压开关和配电系统、中心电站监测系统、发电机组系统、楼宇自控系统、工厂能量管理系统等，能够测三相三线，三相四线系统的电流、电压、有功功率、无功功率、视在功率、有功电能、无功电能、功率因数、频率、开口三角形电压、最大开口形电压等电力参数，同时带有遥信、遥控功能。

After this text introduced and will imitate the audio frequency signal processing as numerical signal after red shoot outside, the numerical signal that will receive again solution adjust after the audio frequency power enlarger enlarge restore in order to imitate the speech signal, shot the electric circuit outside analyzed to design the audio frequency signal before collecting the electric circuit, signal placed the big electric circuit, frequency to make the electric circuit, red, red circumscribed to accept the electric circuit,, frequency the solution adjusted the electric circuit and audio frequencies to enlarge the electric circuit etc.

本文介绍了将模拟音频信号处理为数字信号后经红外发射，再将接收到的数字信号解调后经音频功率放大器放大后还原为模拟语音信号，在分析设计了音频信号采集电路、信号前置放大电路、频率调制电路、红外发射电路、红外接收电路、、频率解调电路以及音频放大电路等各组成部分。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。