一种基于DSP的逆变控制器电路设计

本文介绍一种基于DSP的逆变器,通过逆变电路把直流电转变为交流电,其中SPWM的基波频率是需要的逆变电源的输出频率,该信号经输出变压与隔离,再由LC滤波器滤掉SPWM波中的谐波转成正弦波,从而得到幅值和频率可调的三相交流电。     

基于PLC和变频器的液位控制系统设计与实现

采用PLC为主控制器、变频器为执行器,MCGS监控软件为人机交互界面,设计了一套液位控制系统,并利用西门子S7-200PLC的PID参数自整定功能实现了控制参数的在线自调整。MCGS监控软件构成了控制系统的操作站,可以实现实时数据采集、控制参数输入、控制模式转换等多项功能。在液位控制实验中,MCGS监控软件记录了在设定液位下的PID参数整定过程和设定液位控制效果,S7-200PLC整定出的PID参数较好地实现了设定液位的稳定跟踪。整套系统具有控制灵活、精确度高、故障率低的特点,能满足一般化工生产过程中对液位的控制要求。     

短波信道特征及通信系统关键技术

短波通信具有通信距离远,机动性好,顽存性强等独特优点,在我国军事通信领域占有重要的地位。首先概括短波信道的主要特性,分析短波信道的技术优势,最后就信系统关键技术进行重点探讨。     

Nonlinear Model Algorithmic Control of a pH Neutralization Process

Control of pH neutralization processes is challenging in the chemical process industry because of their inherent strong nonlinearity. In this paper, the model algorithmic control （MAC） strategy is extended to nonlinear processes using Hammerstein model that consists of a static nonlinear polynomial function followed in series by a linear impulse response dynamic element. A new nonlinear Hammerstein MAC algorithm （named NLH-MAC） is presented in detail. The simulation control results of a pH neutralization process show that NLH-MAC gives better control performance than linear MAC and the commonly used industrial nonlinear propotional plus integral plus derivative （PID） controller. Further simulation experiment demonstrates that NLH-MAC not only gives good control response, but also possesses good stability and robustness even with large modeling errors.