Aluminum Electromagnetic Continuous Casting Research And Design Of The Electromagnetic Field In The Computer Control System

The electromagnetically continuous cast-rolling of aluminum is a new technology with high efficiency and less energy-consuming by introducing the electromagnetic technology into the aluminum continuous roll-casting process. The design of a power electrical system to produce electromagnetism with full function and perfect running reliability is the key to realize the technology. In this dissertation, some things about the design of the computer controlled electrical system are researched.The content of this dissertation includes:Ⅰ. The specific requirements of the power electrical system are put forward by analyzing the functional mechanism of electromagnetic roll-casting of aluminum and the effect of many electromagnetic parameters on the size of aluminum crystalline grain during the roll-casting process. In order to match the requirements, the variable frequency converter which is a AC-DC-AC converter with Pulse-width-modulated voltage source inverter(PWM-VSI) is adopted in the system.Ⅱ. According to the whole scheme, the main circuit and the control circuit are designed. The main circuit includes the rectifier and the inverter. The rectifier is three-phase, full-bridge controlled rectifier which is made of thyristors and the inverter is made of IPM.Ⅲ. Aimed at the specific requirements, some strategies are adopted to control the rectifier and the inverter. In order to keep the output current having good stability, current loop and fuzzy control are used in the control of the rectifier. The control of the inverter uses special SPWM. The order of three phases can change, the phasic difference of three phases can alter, the frequency of SPWM can shift with randomicity within a range based on a fiducial frequency.Ⅳ. The control strategies are implemented by using two level computer control system. The language of the program of the MCU is assemble language. The upper computer use DELPHI as main language to program the supervision and control system.The power electrical system have been put into application in the laboratory after its design and test. According to the results, we can drawthe conclusions below:1. Inputting rotated electromagnetic field into the aluminum continuous roll-casting process can decrease the size of aluminum crystalline grain and increase the quality of aluminum products.2. The power electrical system described in this dissertation can produce complex magnetic field which match the special requirements.