| Adding grain refining material in process of aluminum continuous roll-casting production raised cost of product & caused pollution. Focusing on the character, a technology-improving schemes based on electromagnetic fields is designed. After we consulted the domestic and international relevant document materials, a scheme based on 'complex magnetic field formed of frequency conversion magnetic field of vertical pulses & horizontal travelling wave' is established.The control object of this subject is the special electric parameter on the load coil so as to produce the complicated electromagnetic field. VVVF power which the load coil needed is produced by SPWM frequency conversion. PWM pulse produced by microcontroller control frequency of the converter power adjusted at random . And DC power used to produce the additional magnetic field is realized through SCR Rectifier.At first, the fact of aluminum roll-casting & supply-demand is introduced and grain refining mechanism of aluminum based on magnetic field is discussed in this thesis. After control method of special electromagnetism parameter is proposed, we introduce the basis chosen of SPWM frequency conversion & IGBT power module. Then realization of microcontroller based on software and hardware & electromagnetic capability (EMC) of control system are described emphatically. The last chapter summarizes research work & expects research emphasis in future.Feasibility and applied value of the control schemes are verified through industrial-scale tests. |
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