Frequency/time domain modeling of a direct drive point absorber wave energy converter

Two different methods to model a point absorber wave energy converter(WEC)with direct drive linear power take-off(PTO)are proposed in the present study:the frequency domain(FD)method and the time domain(TD)method.In the FD analysis,the frequency response function(FRF)of the WEC device is obtained via the equation of motion,and the expressions of power capture width in regular and random waves are derived as well.In the TD modeling,based on a state space approximation of the convolution term in the motion equation,both regular wave and random wave simulations are carried out.The regular wave simulation results indicate that the state space approximation is sufficiently accurate and the capture width reaches the maximum in the vicinity of the natural frequency.In the random wave simulations,the effects of buoy size,the PTO damping and wave climate on the power capture width are discussed in detail,which leads to the conclusion that the capture widths are influenced by the natural frequency of the WEC device,peak frequency of the wave spectrum,the amplitude of FRF and PTO damping.Furthermore,the increase of the capture width is at the cost of a relatively large buoy size and PTO damping when control is not included.     

一种数字化接收机的实现方案研究

讲述了在宽带中频数字化接收机中的带通采样及抽取技术。通过具体的例子，分析了带通采样定理，多级抽取的应用及HSP50214B数字下变频器各级抽取因子和滤波器设计思路，用软件无线电的思想构造了一个数字化接收机的试验平台。     

RCC自激变换器的分析与设计

RCC是一种自激振荡式变换器,该电路只需要少量的分立元件就可以得到良好的稳压输出性能。其电路结构简单、成本低、高效可靠、可以实现多路输出。文中对RCC电路进行了小信号模型分析,设计了一种两路输出电压型驱动RCC电路,并进行了仿真验证。     

基于DDS的阶梯波合成FPGA控制多电平逆变的设计实现

阐述通过直接数字频率合成技术(DDS)用FPGA设计阶梯波合成的多电平逆变控制的原理和要点,使多电平逆变器控制电路实现数字化控制。研究表明该方案结构合理,具有高频率分辨率,可以实现快速频率切换,适用于不同频率的电力逆变系统,和大规模多电平级联电路的控制设计。     

千兆以太网卡芯片A/D转换电路的设计与实现

介绍了一种用于千兆以太网卡芯片的8位125 MS/s CMOS流水线A/D转换电路的设计,包括体系结构设计、电路设计与仿真、版图设计。该A/D转换电路经过TSMC 0.13μm 1P8MCMOS工艺验证,工作电压为1.5 V/2.7 V。芯片测试结果表明,设计的A/D转换电路能够满足千兆以太网卡芯片的性能要求。     

光伏系统DC/DC变换器设计与仿真

本次研修主要针对整个光伏发电系统前端的DC/DC转换器部分进行研究、设计和仿真。此部分不仅要根据设计要求设计选择合理的占空比和元件参数,完成DC/DC变换,还需要考虑最大能量跟踪控制,以保证最大可能的利用能源,提高系统效率。     

新型恒频ZCS/ZVS准谐振变换器电路设计及实验分析

提出了一种新型恒频率ZCS/ZVS准谐振变换器，其性能优于其它变换器。它具有较小开关损耗、较好的可控性、高操作性能、能够获得可以调节的直流输出电压等优点。并给出这种变换器的电路设计、实验波形以及实验结果分析。     

A 1.2-V 19.2-mW 10-bit 30-MS/s pipelined ADC in 0.13-μm CMOS

A 10-bit 30-MS/s pipelined analog-to-digital converter(ADC) is presented.For the sake of lower power and area,the pipelined stages are scaled in current and area,and op amps are shared between the successive stages. The ADC is realized in the 0.13-μm 1-poly 8-copper mixed signal CMOS process operating at 1.2-V supply voltage. Design approaches are discussed to overcome the challenges associated with this choice of process and supply voltage, such as limited dynamic range,poor analog characteristic device...     

A critical analysis of Z-source converters considering the effects of internal resistances

Nowadays Z-source networks are the most promising power converter networks that cover almost all electric power conversion (dc–dc, dc–ac, ac–dc and ac–ac) applications. However, the controller design is critical for Z-source converter (ZSC) due to the presence right-half-plane zero (RHPZ) in the control-to-capacitor-voltage transfer function. This RHPZ exhibits non-minimum phase undershoot in the capacitor voltage and also in the dc-link voltage waveforms. A perfect small-signal model is required to predict locations of the RHP zero and its dynamics. This paper contributes towards the small-signal analysis of ZSC under continuous conduction mode considering the parasitic resistance of the inductor, equivalent series resistance of the capacitor, internal resistances of active switch and forward voltage drop of the diode. The maximum allowable value of shoot-through duty ratio (STDR) and voltage gain for different values of the internal resistance and load resistance are discussed in this paper. The accuracy of the developed small-signal average model is compared with detailed circuit model in MATLAB/SIMULINK. Finally, the steady-state simulation results of ZSC are validated with hardware results.     

直流脉宽调速系统电流脉动规律分析

本文在研究直流脉宽调速系统的电流脉动规律中,推导了PWM变换器处于不同工作状态时电流动态过程的统一表达式;分析了电动机在不同运行状态下的电流波形,给出了电动运行状态和降速过程的转速、电枢电流和电压的响应曲线;得出了无论电动机处于电动还是制动状态,在一个开关周期内,电枢电压在电源电压和零电压间切换,电流动态过程包括电流上升和下降两段,都遵循所推导出的电流表达式。笔者通过仿真,研究了PWM信号的占空比、开关周期和电磁时间常数等参数对电流脉动幅值的影响。