单元串联中压变频试验系统控制软件设计

为发展完善中压电机变频调速系统,分析了中压大功率变频器试验系统DSP控制软件的结构,设计了主程序、PWM调制模块、顺序控制模块、WF曲线控制模块,给出了各功能块的实现方法,并对试验结果进行了分析.试验表明所设计的中压变频器系统输出稳定、可靠性高且性能优良.     

基于STC单片机的超声波清洗机

针对目前工业清洗问题,设计了一款基于STC单片机超声波清洗机系统。该系统采用STC15F2系列的单片机为控制核心,加以功率调节、半桥逆变、PWM发生与控制等模块电路,利用了调谐匹配和阻抗匹配,使压电换能器输出最大功率。本超声波清洗机具有功率、频率可调、定时清洗的功能,以及清洗效率高、成本低、运行稳定的特点,达到节能环保的目的,应用前景广阔。     

基于TMS320F28234的SVPWM等效方法在逆变系统中的应用

基于两电平情况下,分析SVPWM与载波PWM之间的相互关系,得出SVPWM的基于载波PWM的统一实现方法,给出算法流程图并进行仿真。最后通过基于DSP（TMS320F28234）的逆变电路分别进行开环逆变实验和有源逆变闭环实验。结果证明了该等效方法在逆变系统中的应用是切实可行的。     

Direct Patterning of Self‐Assembled Monolayers by Stamp Printing Method and Applications in High Performance Organic Field‐Effect Transistors and Complementary Inverters

Self‐assembled monolayer (SAM) is usually applied to tune the interface between dielectric and active layer of organic field‐effect transistors (OFETs) and other organic electronics, a time‐saving, direct patterning approach of depositing well‐ordered SAMs is highly desired. Here, a new direct patterning method of SAMs by stamp printing or roller printing with special designed stamps is introduced. The chemical structures of the paraffin hydrocarbon molecules and the tail groups of SAMs have allowed to use their attractive van der Waals force for the direct patterning of SAMs. Different SAMs including alkyl and fluoroalkyl silanes or phosphonic acids are used to stamp onto different dielectric surfaces and are characterized by water contact angle, atomic force microscopy, X‐ray diffraction, and attenuated total reflectance Fourier transform infrared. The p‐type dinaphtho[2,3‐b:2′,3′‐f]thieno[3,2‐b]thiophene (DNTT) and n‐type F₁₆CuPc OFETs show competitive mobility as high as 3 and 0.018 cm² V^?1 s^?1, respectively. This stamp printing method also allows to deposit different SAMs on certain regions of same substrate, and the complementary inverter consists of both p‐type and n‐type transistors whose threshold voltages are tuned by stamp printing SAMs and shows a gain higher than 100. The proposed stamp or roller printing method can significantly reduce the deposition time and compatible with the roll‐to‐roll fabrication.     

面向地铁车辆的辅助逆变系统设计

为使地铁辅助逆变系统在负载突变过程中能够保持输出电压稳定性,从而满足地铁辅助逆变系统需求,本文提出一种面向地铁车辆的双级功率变换高频辅助逆变系统结构,采用TDSVPWM调制算法和DSP+FPGA的控制框架,实现了良好的负载跟踪性能。通过MATLAB仿真和实验平台试验,证明该系统在负载突变过程中能够保持电压稳定性,运行状态良好。     

Synthesis of lumped dual-frequency impedance transformers for complex loads using inverters

Novel lumped dual-frequency impedance transformers (DFITs) for arbitrary frequency dependent complex loads (FDCLs) are synthesized using the concepts of capacitive and inductive inverters. Such a dual-frequency impedance transformer is constructed with one Pi-shaped lumped inverter and two shunt susceptance blocks at two sides, and get simplified after susceptance merging. The shunt susceptance blocks have specified susceptance values at two frequencies and are realized with lumped circuits of certain topologies. Design formulas of the DFITs are derived and are validated by two examples. Compared with a former technique, this method uses less lumped elements and provides one design freedom, so largest matching bandwidths can be achieved by comparing a series of possible designs.     

一种新型Z源逆变器

为提高Z源逆变器升压能力同时减小电容应力,提出了一种电源嵌入式Z源逆变器的电路拓扑理论;采用了开关电感和直流电源嵌入分支电路的拓扑结构,通过分析该拓扑的储放能过程,及其基本结构和工作原理,利用MATLAB/Simulink仿真软件进行了验证,最后基于DSP-TMS320F2812控制平台搭建样机进行实验验证,仿真及实验结果表明,该拓扑结构是可行的准确的;在有效提高逆变器的升压能力的同时降低了电容电压的应力。     

A novel photovoltaic inverter topology based on common mode current suppression

ABSTRACT

Aiming at the problems of large leakage current and low efficiency of existing transformerless single-phase grid-connected photovoltaic inverters, a novel transformerless single-phase grid-connected photovoltaic inverter topology is proposed. In this topology, two freewheeling diodes are added to the single-phase full-bridge inverter, and the filter inductors are moved between the upper and lower bridge arms, so that the common mode voltage remains constant during the switching period and the common mode current is effectively suppressed. Finally, through simulation and the experimental platform of 3kW single-phase grid-connected photovoltaic inverter, it is verified that compared with the traditional full-bridge topology, the novel topology can effectively suppress the common mode current, while compared with the H5 and H6 topology, the novel topology reduces the system loss and improves the system efficiency.     

Two new impedance source network topologies for inverter applications

In the last decade, the impedance source networks have been vastly used in electrical power conversion such as in electric vehicles, industrial machines, medical systems and avionics, with considerable efficiency improvements. In this study, two new impedance source network topologies for inverter applications have been designed and tested. The first one is a one-cell switched inductor (SL), the second is a two-cell switched inductor (X-SL) combined with the classical Z-source inverter (ZSI). This novel combination allows the switched inductor to store the unused source energy in the interval when the source separates from the ZSI network during the shoot-through zero state. The design is generalised by adding multiple branches of series inductors and diodes which further improve the circuit performance. The National Instrument Multisim programme is used for the simulations of the new topologies. Both of the proposed topologies, SL combined with classical ZSI (SL&ZSI) and X-SL combined with classical ZSI (X-SL&ZSI), are tested with specific inductance and capacitance values. Major improvements are observed in the boost factor and the elimination of the start-up inrush current for both topologies, compared to the classical ZSI scheme. Furthermore, in both topologies, a significant reduction in the capacitor stress levels is obtained.     

SINAMICS G120变频器在恒压供水系统中的应用

文章介绍了SINAMICS G120变频器调速技术在恒压供水中的应用,阐述了恒压供水的工作原理,变频器外部接线端子功能,工艺控制器参数设置及调试方法。