Design Research On Ultrasonic Power Used In Aluminum Alloy Casting Process

Aluminum is one of the most widely used metal alloys and also the most important strategic resources to domestic industry even military affairs. In this case, improving the production of aluminum alloy has extremely vital significance. Introducing a certain power ultrasound to the process of crystallization of molten aluminum, such as the ultrasonic cavitation, acoustic streaming effect and other special physical effects can effectively refine the grain and improve the ingot surface quality. Ultrasonic generator that applied to casting process, i.e. the ultrasonic power, is a crucial part in the ultrasonic processing system. The performance of ultrasonic power affects the processing of the results directly, thus the according academic research can be very significant.This paper focuses on the analysis of power performance requirements during the aluminum alloy casting process. Based on the aim of easy-implemented and working stability, this paper proposes to construct the main circuit structure with the diode rectifier, chopper voltage regulation and single-phase bridge inverter frequency modulation.Three major technical issues related to ultrasonic power's performance are considered in this paper: including the frequency control, power control and load matching. First, the study of frequency control methods such as fuzzy control and integrated PLL combined helps to maintaining the resonant condition of load, and further maximize the power output current by frequency modulation. Second, the management of power output power can be carried out by PID control mode, which is based on the error of judgment and aims at control the chopper output voltage. Last, under the theory frame of dynamic matching load, tuning matching inductance is designed. In this process, impedance matching transformer was used to increase power output on impedance transformation properties of transformer.Using TMS320F2812 as the core of the control system, drive circuit, sampling circuit, protection circuits, man-machine interface circuit hardware components and control system software were designed. The use of MATLAB on the power system modeling and simulation showed that the design of the control method can improve the power system performance effectively. Therefore, the design expectations are fulfilled and theoretical analysis in this paper is proved to be feasible.