Research On Multi-Frequency And Variable- Power Ultrasonic Equipment For Chinese Medicine Extraction

The ultrasonic extraction for Chinese medicine has made rapid progress in recent years due to its high extraction rate, short extraction time and physical extraction feature. As the development of the ultrasonic extraction for Chinese medicine, different ultrasonic devices are adopted in the extraction experiment, and researchers explore the optimal parameters of the devices based on the mass experiment data. However, the current ultrasonic equipment for Chinese medicine extraction all only have the single frequency and power, which brings inconvenience for the research of the optimization of the extraction process. This paper has delved into the ultrasonic generation technology, impedance matching technology for multi-frequency transducer, and the frequency tracking technology. And this paper also designed a variable power and multi-frequency ultrasonic generation device based on the multi-frequency transducer, which can be effectively used in the experiments of Chinese medicine extraction. Firstly, conducting research on the principle of the impedance matching technology of ultrasonic transducers. And also, on the basic of the traditional single frequency impedance matching, this paper has excogitated a dynamic impedance matching method, which aims at characteristics of the multiple frequency transducer impedance matching. As a result, the multi-frequency impedance matching technology is realized.In addition, delving into the frequency drift of the ultrasonic transducers. And aiming at the characters of the multiple frequency transducer, this paper has designed a composited frequency tracking method based on PLL and current feedback, which can solve the multiple-frequency transducer tracking problem.Finally, debugging the hardware system, and making some analysis of the real problem found in the debugging process. Then, all separated modules are integrated for the experiment in honeysuckle flowers extraction. The result proved that this device have the advantages of multi-frequency, variable power, and high working efficiency, which brings a reference for the research of industrial multiple-frequency ultrasonic extraction equipment in the future.