Research And Development Of Microcomputer Control System For The SCR Rectifier

The high-power electronic rectifier technology is widely used in the electricpower, chemical, metallurgy, iron and steel industry, and other important areas of thenational economy, based on SCR phase-controlled rectifier technology is one of whichthe most developed and widely used. The trigger control system is the key to stableand reliable operation of phased rectifier circuit. Given the breadth, diversity andcomplexity of controlled object of the phase-controlled rectifier circuit, the design ofthe trigger control system with high-performance and versatility has become the focusof wide attention and research in the field of scientific research and engineering.As the rapid development of microcomputer control technology and micro-electronics manufacturing technology, the microcontroller represented by micro-controller chip, for its low price and reliable performance, has become the main forceof the digital control technology in the field of control engineering applications.Based on industrial grade MPC series microcontroller, the trigger and control systemof the thyristor rectifier is designed and developed as a single-chip control system,which is combined digital trigger and digital regulator. Through the experiment, it isproved that, the trigger pulse generated by the system has high real-time quality andcontrol accuracy, and can achieve triggering phase-controlled rectifier circuit withlong-term, stability and reliability, and is able to complete a precisely regulatedoutput DC voltage (current). Systematic summary of the research and developmentwork is carried out as below.Firstly, the controlled objects of the SCR rectifier system are analyzed in detail,and corresponding mathematical models are established, and then, the basic principleand hardware structure of the trigger and control system of thyristor rectifier isdescribed. part of the hardware is including the main circuit of the thyristor rectifiersystem and the control loop. The main circuit is included supply power andthree-phase bridge rectifier circuit; The control loop is included the power sync signalacquisition module, feedback and given signal sampling module, parameter settingsand data storage module, the pulse phase shift trigger and output module, digitalvoltage and current regulation module and other auxiliary function modules, etc.Secondly, the software processes of the trigger and control system of thyristorrectifier is designed on the Keil compiler platform, including phase sequence detection and phase shift trigger subroutine, signal sampling and processingsubroutine, regulate and control subroutine, state detection and indication subprogram,debug subroutine parameter tuning subroutine. And through the experiments producedby the test device verify the correctness of each part of the designed program.In addition, the trigger and control system of thyristor rectifier is debuged, andcorresponding test waveforms and data are given, and also the problems as well assolutions of hardware and software appeared during the debugging process aresummarized and. And then the system’s overall test is completed, the test results showthat trigger pulse produced by the system has high reliability and stability, and meetthe requirement of the rectifier circuit for triggering.Finally, as a device upgrade options, the intelligent control based on fuzzy-PIDalgorithm and bias-separated feedback linearization control algorithm were designed,and the simulations of the controller based on the algorithms were carried out, fordefierent performance requirements of the rectifying the system. The results Obtainedby the simulations verify the effectiveness of the two control strategies.