Design Of Intelligent Sonochemical Ultrasound Generator Based On Embedded System

The study described in this dissertation root in a project which name was parameters optimizes and mechanism research on ultrosound water disposal machines. The project was supported by National Natural Science Foundation of China (grant No. 10574038). The main objectives of this thesis were to research and design an efficient high-power and intelligent ultrasonic generator that was used in sonochemical reactor.Sonochemistry has become a new embranchment of chemistry, and is making a figure in exploring of safety, cheapness and non pollutive chemistry industry. However, the design of sonochemistry reactor is a decisive approach to application of sonochemical industry. And, the design of ultrasonic generator is a key step in the design of sonochemistry reactor.The character of ultrasonic generator and the merit of embedded technology were analyzed in the thesis. And an ultrasonic generator based on embedded technology was designed. The whole system was made up of micro-controller unit, signal generator, power amplifier, frequency auto-tracking unit, matching network, user interface, and communication module. The details were as follows:Firstly, the principle of direct digital frequency synthesis (DDS) was analyzed. And a broadband, the frequency from 15 kHz to 9 MHz, signal generator based on DDS was designed. Secondly, amplifier for ultrasonic generator .was studied, and an amplifier consisting of class-A preamplifier and push-pull amplifier was designed. Thirdly, impedance matching of ultrasonic generator and transducer was research, and transmission line transformer was used to match impedance. Finally, the impedance characteristic of piezoelectricity transducer and the principle of frequency tracking were studied. Software phase-locked loop was used to track self-adapting frequency, and arithmetic of frequency tracking based on change step and dichotomy was presented.Besides above study, the dissertation focused on studying embedded system used in controlling ultrasonic generator. An embedded hardware was designed based on LPC2104, an ARM7TDMI microprocessor (MPU). Then, μC/OS-II, a Real Time Operation System, was analyzed. In order to ensure that embedded system was more efficient and reliable, the RTOS was transplanted to LPC2104. An integrated embedded system was constructed after application software was designed. The dissertation explored intelligently controlling ultrasonic generator, and achieved some aims of the project supported by National Natural Science Foundation of China.