Novel approach to harmonic control for Class F power amplifier with high power added efficiency

This paper presents a new topology to implement Class F power amplifier for eliminating the on-resistance (R_(ON))effect.The time-domain and frequency-domain voltage and current waveforms for Class F amplifier are ana- lyzed using Fourier series analysis method.Considering the on-resistance effect,the formulas of the efficiency,output power,dc power dissipation,and fundamental load impedance are given from ideal current and voltage waveforms.For experimental verification,we designed and implemented a Class F power amplifier,which operates at 850 MHz using MGaAs/GaAs Heterostructure FET(HFET)device,and analyzed the measurement results.Test results show that the maximum PAE of 67% can be achieved at 28 dBm output power level.

PERFORMANCE ANALYSIS OF POWER SAVING CLASS OF TYPE Ⅲ IN IEEE 802.16E WITH USER INITIATED TRAFFIC

A novel method for analysing the performance of power saving class of Type III in IEEE 802.16e is proposed, which is applicable to design, maintenance and management for mobile wireless metropolitan area network. Considering the memoryless nature of user initiated packet arrival, a Geom/G/1 queue model with multiple vacations and setup period is built to capture the principle for the power saving class of Type III. By using an embedded Markov chain method and the boundary state variable theory, we obtain the queueing measures such as queueing length, waiting time and busy cycle in steady state. Correspondingly, we derive explicitly the performance measures for the power saving class of Type III in terms of handover ratio, energy saving ratio, and average packet response time. Based on numerical results, we develop a cost function to determine numerically the optimal length of sleep window and the minimal cost with different offered loads.

Using LDMOS Transistor in Class-F Power Amplifier For WCDMA Applications

The fundamental operating principle of a Class F power amplifier and the factors aiding or affecting Class F performance were explicated previously. A Class F power amplifier design which satisfies WCDMA specifications is explained in this paper. The Class F amplifier was designed by employing Motorola’s LDMOS (Laterally Diffused Metal Oxide Semiconductor) transistor models and we simulated its performance by means of ADS. A variety of procedures were applied in the process of designing Class F amplifier, namely, DC simulation, bias point selection, source-pull and load-pull characterization, input and output matching circuit design and the design of suitable harmonic traps, which are explained here.

Analysis of the third harmonic for class-F power amplifiers with an Ⅰ–Ⅴ knee effect

The appearance of third-generation semiconductors represented by gallium nitride （GaN） material greatly improves the output power of a power amplifier （PA）, but the efficiency of the PA needs to be further improved. The Class-F PA reduces the overlap of drain voltage and current by tuning harmonic impedance so that high efficiency is achieved. This paper begins with the principle of class-F PA, regards the third harmonic voltage as an independent variable, analyzes the influence of the third harmonic on fundamental, and points out how drain efficiency and output power vary with the third harmonic voltage with an I-V knee effect. Finally, the best third harmonic impedance is found mathematically. We compare our results with the Loadpull technique in advanced design system environment and conclude that an optimized third harmonic impedance is open in an ideal case, while it is not at an open point with the I-V knee effect, and the drain efficiency with optimized third harmonic impedance is 4% higher than that with the third harmonic open.

Inner Mongolia builds up world's class wind power generation farm

The first phase project of Huitengxile Wind Power Generation Farm in Inner Mongolia, with nine 600 kW wind power generators installed, was formally put into commercial operation on November 28,

Study of the Effect of Using Power Point in an English Class

This action research aims to work out whether the effect of using powerpoint in an English class is positive or not.This research is carried out through the researcher’s lessons to a class of 45 students,experienced teachers and a philosophy teacher after previous meeting with the researcher are invited to observe the lessons with observation forms,questionnaires are completed by the students in the class and after class discussions.The conclusion from this action research is that in the context of the time and place when research is made,the Effect of Using Power Point in an English class is positive.

A High Power-Added-Efficiency 2.5-GHz Class-F Power Amplifier Using 0.5 μm GaN on SiC HEMT Technology

This paper proposed the high-frequency, multi-harmonic-controlled, Class-F power amplifier (PA) implemented with 0.5 μm GaN Hetrojunction Electron Mobility Transistor (HEMT). For PA design at high frequencies, parasitics of a transistor significantly increase the difficulty of harmonic manipulation, compared to low-frequency cases. To overcome this issue, we propose a novel design methodology based on a band-reject, low-pass, output matching network, which is realized with passive components. This network provides optimal fundamental impedance and allows harmonic control up to the third order to enable an efficient Class-F behavior. The implemented PA exhibits performance at 2.5 GHz with a 50% PAE, 14 dB gain, and 10 W output power.

A 1.8 GHz Power Amplifier Class-E with Good Average Power Added Efficiency

This paper presents a 1.8 GHz class-E controlled power amplifier (PA). The proposed power amplifier is designed with two-stage architecture. The main advantage of the proposed technique for output control power is a high 37 dB output power dynamic range with good average power adding efficiency. The measurement results show that the PA achieves a high power gain of 23 dBm and power added efficiency (PAE) by 38%. The circuit was post layout simulated in a standard 0.18 μm CMOS technology.

X-band inverse class-F GaN internally-matched power amplifier

An X-band inverse class-F power amplifier is realized by a 1-mm Al Ga N/Ga N high electron mobility transistor（HEMT）.The intrinsic and parasitic components inside the transistor,especially output capacitor Cds,influence the harmonic impedance heavily at the X-band,so compensation design is used for meeting the harmonic condition of inverse class-F on the current source plane.Experiment results show that,in the continuous-wave mode,the power amplifier achieves 61.7% power added efficiency（PAE）,which is 16.3% higher than the class-AB power amplifier realized by the same kind of HEMT.To the best of our knowledge,this is the first inverse class-F Ga N internally-matched power amplifier,and the PAE is quite high at the X-band.

Power Quality Disturbance Classification Method Based on Wavelet Transform and SVM Multi-class Algorithms

The accurate identification and classification of various power quality disturbances are keys to ensuring high-quality electrical energy. In this study, the statistical characteristics of the disturbance signal of wavelet transform coefficients and wavelet transform energy distribution constitute feature vectors. These vectors are then trained and tested using SVM multi-class algorithms. Experimental results demonstrate that the SVM multi-class algorithms, which use the Gaussian radial basis function, exponential radial basis function, and hyperbolic tangent function as basis functions, are suitable methods for power quality disturbance classification.

Integrated Delta-Sigma 1.5bit Power DAC with 100dB Dynamic Range

A stereo 1.5bit delta-sigma digital-analog converter （△∑ DAC） integrated with a filterless class D power amplifier is introduced. It consumes no static power, and its maximum output power is 436mW with an 8Ω load. Its output dynamic range exceeds 100dB. The circuit is implemented with a TSMC 0. 18μm process. The die area is 0. 28mme. The supply voltage is 1. gV for the digital part and 3.3V for class D.

基于π型谐波控制网络的高效功率放大器设计

为了提高通信系统的工作效率,提出一种基于F类理论的π型谐波控制网络。该网络利用直流偏置电路引入二次谐波短路点,从而降低谐波控制电路的复杂度;同时,能够确保二次、三次谐波阻抗不受后续基波匹配电路的影响。为避免寄生参数对晶体管芯漏极阻抗的影响,在π型谐波控制网络与晶体管之间引入L型寄生补偿电路,实现二次谐波阻抗趋近零、三次谐波阻抗趋近无穷大。为验证所设计网络的可行性,设计一款高效率F类功率放大器并进行仿真测试,结果表明在1.8~2.1 GHz工作频带内,饱和输出功率为43.21~44.84 dBm,增益为13.21~14.84 dB,功率附加效率为69.59%~73.54%。由此证明了所提出的π型谐波控制网络在高效率放大器设计中能够很好地满足各项性能指标。

Class-AB型低功耗轨到轨CMOS模拟缓冲器设计

设计了一种新型Class-AB轨到轨CMOS单位增益模拟缓冲器。实现电路基于并行互补差分对输入,在保持整个电路简洁的同时,可提供低功耗Class-AB输出方式,使电路实现轨到轨的电平跟踪功能。使用0.35μm工艺库仿真,结果表明,该缓冲器具备较大的电容驱动能力,可以应用在具有大电容负载的场合。使用特殊设计方式,使电路主极点移动到输出节点上,彻底解决了大负载电容下电路的稳定性问题。电路使用3.3V单极性电源,在负载电阻大于1MΩ时,可以提供完全的轨到轨输出。在20pF负载电容时,输出摆率为+7.9V/μs和-5.8V/μs,整个电路的静态功耗仅为184μW。

基于NSGA-Ⅱ算法的微电网无功分区节点选择

无功分区节点错误规划会导致微电网实时功率异常增大,从而造成电能过量消耗的问题。为控制微电网实时功率水平,选定正确的无功分区节点,提出基于NSGA-Ⅱ算法的微电网无功分区节点选择方法。利用NSGA-Ⅱ算法分析微电网局限性,定义无功区域划分原则,完成微电网无功区域划分。求解微电网无功分区内的类间合并距离,通过修正无功功率的方式,选择必要的分区节点,完成微电网无功分区节点选择方法的设计。实验结果表明,所提方法可将微电网实时功率控制在4.0×10~9kW之下,达不到微电网的额定功率水平,表示所选择无功分区节点不会造成微电网电能过量消耗的问题。

基于SOI-0.18 μm高PAE CMOS Class-E功率放大器

基于IBM SOI-0.18μm CMOS工艺,实现了高PAE的Class-E功率放大器.此放大器由两级构成.在输出级采用了负电容技术,抵消寄生电容,提高效率.输出级的共栅管采用自偏置,防止晶体管被击穿.驱动级采用Class-E结构,使得输出级能更好地实现开与关.两级之间使用了改善输出级电压和电流交叠的网络.通过使用这些技术,在2.8V电源电压下,功率放大器工作在2.4GHz的时候,输出功率为23.44dBm,PAE为58.99%.

基于UML/Power Designer的信息系统分析方法

本文主要针对基于UML/PowerDesigner的信息系统分析方法进行研究:在基于面向对象UML的平台上,以CRM客户关系管理信息系统为研究对象,对其需求模型,总体设计模型和详细设计模型进行了分析设计,并采用了基于UML建模语言的CASE工具PowerDesigner进行进一步的辅助分析和设计,得到了CRM的相关实现模型。本文的研究对管理信息系统的分析方法提供了一种实用的技术途径。

基于Class-D功率放大的超声波电动机驱动方案

研究了一种基于有源滤波器和D类(Class-D)功率放大的新型高性能超声波电动机驱动方案。基于有源滤波器设计了频率、幅值、相位可调的正弦信号发生器,设计了基于Class-D功放的功率放大和匹配电路。通过匹配电路仿真分析验证了该方案的设计思想。在现有旋转行波超声波电动机上将所提方案与传统脉宽调制(PWM)逆变式驱动方案进行了对比实验,对两种驱动电路产生的波形进行了频谱分析。实验结果显示,与PWM逆变式驱动方案相比,基于有源滤波器和Class-D功率放大方案的驱动波形谐波分量较少,能量损耗较小,同时缩小了驱动器体积,有利于实现超声波电动机驱动器的小型化。

基于图像分割及小波脊线的变压器绕组状态检测

新型电力系统的建设给电力设备及电网的安全可靠运行提出了更高的要求,进一步提升了变压器绕组状态的检测水平,该文从变压器振动信号的小波时频图像出发,使用最大类间方差法对其进行图像分割以获取表征绕组状态信息的关键区域,进而利用模极大值法提取经图像分割后各关键区域的小波脊线,据此定义了小波脊线特征向量与特征向量角(WRFVA),对变压器绕组状态进行检测。某110 kV变压器多次短路冲击试验下振动信号的计算结果表明:经图像分割提取出的变压器振动信号小波时频图像的小波脊线时频分辨率高,直观清晰地反映了不同短路冲击电流作用下绕组状态的变化过程;当同一短路电流作用下振动信号的WRFVA的变化超过2°时,意味着绕组有轻微松动或变形存在,建议关注其运行状态。