【作者】 王辉；

【导师】 李宏；

【作者基本信息】 西安石油大学 ， 电力电子与电力传动， 2018， 硕士

【摘要】 电渣炉是冶金领域生产电渣锭的特殊冶炼设备,其供电方式为单相交流供电,且随着炉体吨位的不同,需求电流达到几千至数万安培。传统电渣炉因常规变频器输出电流的局限性不得不使用工频直接供电,此种供电方式,分布电感不可忽视,导致系统功率因数多在0.8以下,电能浪费严重,且因单相供电,无法保证三相平衡,引起电网波形畸变,导致谐波污染严重。在现代工业提倡节能减排的形势下,本文采用从工频三相到低频单相的交-交变频方案,将供电电源频率降低,减少感抗压降,提高功率因数。本文针对低频电源的技术难点,为提高供电系统的功率因数,降低谐波污染,设计了输出10.8MW,1~5Hz可调的300T电渣炉单相低频供电电源变换系统,考虑到晶闸管数量较多、钢质整流柜壳体因涡流发热及扩大输出电流容量等问题,经比较,主电路的基本拓扑结构选为带平衡电抗器的双反星形同相逆并联交-交变频电路。为降低注入电网电流的谐波和系统运行时电网电压的脉动频率对系统运行的影响,变压器设计为24脉波整流变压器。应用有载调压器粗调和晶闸管细调相结合实现输出电压、电流的精确控制,保证系统在不同的工况下都有较高的功率因数。采用以DSP和CPLD为核心单元的全数字化、相位自适应触发控制板,确保多路脉冲同时产生。整套系统还设计了完善的电压、电流信号检测与处理电路、保护电路和监控电路。最后,对软硬件设计进行仿真和调试,验证设计结果的正确性和可行性,进一步证实降低电渣炉供电电压频率,可以提高功率因数,减少电能浪费。更多还原

【Abstract】 Electroslag furnace is a special smelting equipment for the production of electroslag ingots in the field of metallurgy.It often uses single-phase alternating current power supply.With the different tonnage of the furnace body,the current demanded from several thousands to tens of thousands of amps.The traditional electroslag furnace has to use the power frequency power supply directly because of the limitations of the conventional inverter output current.Since the distributed inductance can not be ignored,the power factor is mostly below 0.8 by this kind of power supply mode,it is a serious waste of electrical energy.Due to the single-phase power supply,the three-phase balance cannot be guaranteed,causing distortion of the power grid waveform and causing serious harmonic pollution.Under the situation in which modern industry promotes energy conservation and emission reduction,this paper adopts an AC-AC frequency conversion scheme from power frequency three-phase to low-frequency single-phase.This design reduces the frequency of the power supply in order to reduce the pressure drop of the inductive reactance and increase the power factor.The article against the technical difficulty of low-frequency power,this paper designs a single-phase low-frequency power supply conversion system for single-phase 300 T electroslag furnace with 10.8MW output and 1~5Hz output in order to improve the power factor of the power supply system and reduce the harmonic pollution.the large number of thyristors,steel rectifier cabinet due to eddy current heating and expanding the output current capacity and other issues is considered,the basic topology of the main circuit is selected as a double anti-star inverse in parallel with the balance reactor AC-AC inverter circuit after comparison.In order to reduce the influence of the harmonics injected into the grid current and the fluctuating frequency of the grid voltage during system operation,the transformer design a 24 pulse rectifier transformer.The combination of on-load voltage regulator coarse adjustment and thyristor fine adjustment enables precise control of the output voltage and current to ensure that the system has a higher power factor under different operating conditions.All-digital,phase-adaptive trigger control board with DSP and CPLD as the core unit is used to ensure simultaneous generation of multiple pulses.The whole system has also designed perfect voltage/current signal detection and processing circuit,protection circuit and monitoring circuit.Finally,the software and hardware design are simulated and debugged to verify the correctness and feasibility of the design results.It is further confirmed that reducing the frequency of the electric slag furnace power supply voltage can improve the power factor and reduce the energy waste.更多还原