A new ZVT–ZCT quasi-resonant DC link for soft switching inverters

In this article, the new ZVT–ZCT Quasi-Resonant DC Link, which ensures zero crossings at any time required for soft switching (SS) and provides zero voltage transition (ZVT) turn-on and zero current transition (ZCT) turn-off together for the main switch of active snubber cell in pulse width modulated or space vector modulated operation of inverter is presented. The new circuit combines the most desirable features of the circuits presented previously and overcomes most drawbacks of these circuits by using only one auxiliary switch with fewer other components. Consequently, new ZVT–ZCT Quasi-Resonant DC Link, which is verified by a prototype of a 1.2 kW and 50 kHz circuit, is analysed in detail. All semiconductor devices operate under SS, the main switch is subjected to no additional voltage and current stresses, and the stress on the auxiliary switch is very low in the proposed new inverter.     

Output feedback and dynamical sliding-mode control of power converters

Using the underlying idea of the most widely accepted controller for power converters, the current-mode control, a new dynamical and sliding-mode control for dc–dc power converters, is proposed. The controller requires only voltage measurements; is easy to design; is robust under load and input voltage variations, exhibits fast response and does not depend on the load (although a knowledge of the load range is necessary to tune the controller). In spite of these features, it can be easily implemented using standard electronics components. The stability analysis is carried out using the discontinuous (large signal) nonlinear model. This analysis provides a set of controller admissible parameters to keep closed-loop system stability.     

Integrated on-chip 0.35 μm BiCMOS current-mode DC–DC buck converter

A current-mode DC–DC buck converter with a fully integrated power module is presented in this article. The converter is implemented using BiCMOS technology in amplifier and power MOSFET in a current sensor. The current sensor is realised by the power lateral double-diffused MOSFET with the aspect ratio much larger than that of a matched p-MOSFET. In addition, BiCMOS technology is applied in the error amplifier for an accurate current sensing and a fast transient response. The DC–DC converter is fabricated with 0.35?µm BiCMOS process. Experimental results show that the fully integrated converter operates at 1.3?MHz switching frequency with a supply voltage of 5?V. The output DC voltage is obtained as expected and the output ripple is controlled to be within 2% with a 30?µH off-chip inductor and 100?µF off-chip capacitor.     

Voltage–frequency converter for laser welding control

An experimental model of a voltage–frequency converter was realised and utilised for the control of the thermal behaviour by the laser welding of thermoplastic polymer materials. The input signal of 0–10?V comes from a thermal–optical real-time analysing device of the welding process. The output signal of 0–300?Hz is introduced to the input interface of a laser welding equipment, for setting the laser pulse frequency. Operation tests were performed on the laser welding equipment type HL 124P LCU. The pulses have rectangular waveform, with the amplitude of 20?V. The frequency is very stable, with deviations of less than 0.5?Hz. The waveform and the frequency response at the converter output are appropriate.     

Pulse amplitude-modulated time-based interface for off-chip interconnect

An increased number of bits pulse amplitude-modulated differential-time signalling interface for off-chip interconnect is introduced in this article by combining the differential time signalling (DTS) technique with the pulse amplitude-modulation (PAM) approach. Applying the PAM to the DTS-transmitted signal increases the total number of the transmitted bits per symbol while maintaining the transmitted signal bandwidth. 4-bit 6 Gb/s DTS serial link has been designed and simulated using 65 nm CMOS mixed signal technology. 5-bit 7.5 Gb/s and 6-bit 9 Gb/s amplitude-modulated DTS serial links have been designed, simulated and compared to the 6 Gb/s DTS serial link. The three serial links use 1.5 Gb/s as input clock signal. In the amplitude-modulated DTS-transmitted signal, the rising and falling edges of the input clock signal are modulated in time as well as the transmitted signal amplitude is modulated. A reference clock pulse is generated from the input clock signal and embedded on the transmitted signal to be used as reference timing at the receiver circuit. The design details of the designed links are presented in the article. The 9 Gb/s link uses a 60 cm 4003C Rogers substrate as a transmission channel. The transmitted signal spectrum is presented and compared for the three designed links. The total power consumption of the 9 Gb/s amplitude-modulated DTS interface is less than 25 mW.     

一种改进的多模数字下变频结构及其FPGA实现

针对目前多种通信模式的共存和发展趋势,对传统DDC结构进行改进,以适用于多模系统。提出了多模数字下变频改进结构与参数设计,完成了各模块Verilog代码编写和Modelsim仿真,并对Modelsim仿真结果进行分析和验证,验证了改进数字下变频的可行性;最后将代码移植到FPGA,并结合ETTUS射频板、自主设计的中频板以及友晶TR4 FPGA开发板多模硬件平台进行了板级调试,验证了多模功能的可行性,充分证明该结构能兼容WCDMA和TD-LTE两种模式,具有较高的实用性和通用性。     

基于双向PWM变换器的微燃机发电系统起动／发电控制研究

针对微型燃气轮机（微燃机）发电系统的特点,建立了以电压型双向脉宽调制（PwM）变换器为功率变换装置的起动／发电控制模型。微型燃气轮机发电系统起动时,采用矢量控制;发电运行时,采用电压外环电流内环的双环PWM整流控制。仿真实验结果表明：起动时,高速永磁同步电机（PMSG）采用矢量控制比速度开环控制性能更优,减少了起动时间,满足快速起动的要求;发电运行时,与二极管整流相比,PWM整流能使交流侧电流跟踪发电机的感应电动势,功率因数约为1,降低了发电机侧的电流谐波,即减少了谐波热。同时保证了发电机在一定宽速范围内,输出直流电压稳定,并且在起动一发电过渡转换过程中,直流母线电压降落后,快速恢复为稳定值,满足平滑转换的要求。     

ADC模数转换器有效位计算

将模拟信号转换为数字信号后再进行处理,是当前信号处理普遍使用的方法,模数转换器（ADC）就是将模拟信号转换为数字信号的器件,所以计算其有效转换位数对系统性能评估就显得尤为重要。文中结合项目工程实践,讨论了ADC有效转换位数的两种测试方法:噪声测试法和信噪比测试法,并对两种方法进行了仿真与分析。     

Inductor Current Sampled Feedback Control of Chaos in Current-Mode Boost Converter

A chaos control strategy for chaotic current-mode boost converter is presented by using inductor current sampled feedback control technique.The quantitative analysis of control mechanism is performed by establishing a discrete alterative map of the controlled system.The stability criterion,feedback gain,and corresponding critical duty ratio are obtained from the eigenvalue of the map.The simulation results verify the t heoretical analysis results of the control strategy.     

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??Aimed at relevancy chemical equilibrium, material balance and thermal equilibrium of the reaction stove and converter of Claus sulfur recovery by direct method, this paper establishes two nonlinear equations sets, and carries out numerieal calculation by use of the Newton-Raphson algorithm for derivation, measures the composition from the mouth of reaction stove and converter, and calculates the optimum air ration and the optimum reaction temperature. The related problems are discussed and some examples calculated are given.