| Large-scale electroslag furnace is a necessary equipment for smelting high-quality large-scale ingots on the basis of electroslag remelting technology.With the urgent demand for large steel ingots in China,and the development strategy of eliminating low efficiency and high energy consumption industry.The problems of high inductance pressure drop,low power factor and no closed-loop voltage stability are becoming more and more prominent in the electric power supply system of electroslag furnace.It is of great practical significance to discuss the power supply scheme and control strategy of high efficiency and flexible electroslag furnace.In order to solve the above problems,the theoretical basis of reducing the power supply frequency and reducing the control angle of thyristor to improve the power factor is studied.Then the control strategy of high power factor low frequency power supply for single-phase electro-slag furnace is studied,and the control scheme of thyristor control angle and on-load voltage regulating switch gear is designed.By using PID algorithm,the power supply frequency is reduced.Maintain the output voltage stability while maintaining the thyristor control angle in a small range of design objectives.Then,the simulation system is built with the help of simulation software,and the feasibility of this scheme is verified by comparison and analysis.On this basis,the DSP chip is designed as the core,and the CPLD chip is used as the assistant,peripheral synchronous signal acquisition,trigger pulse isolation and amplification,signal conditioning and communication circuit is designed.The feasibility of the scheme is further verified through the debugging of single-phase 55V/2.2kA low frequency power supply for electroslag furnace,which provides a good reference for the improvement and renewal of the existing electroslag furnace equipment in our country and is of great significance. |
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