EFFICIENCY OF DIRECT PIEZO DISCHARGE GENERATION DEPENDING ON THE WAVEFORM AND FREQUENCY OF THE INPUT SIGNAL FROM THE DEVELOPED GENERATOR

Cold atmospheric pressure plasma based on a piezo discharge is of great interest in many areas of human activity. This relatively new cold plasma source can be used from various plasma surface treatment methods, to various applications in the food industry, biology, genetics and medicine. The purpose of this study is to establish the dependence of the generation efficiency of piezodischarges on the frequency and shape of the applied signals. For the study, a compact source of cold plasma with a rigid control coupling from the generator was developed. The generation frequency is analyzed by an oscilloscope, using a connected loop magnetic antenna, depending on the shape and frequency of the signal supplied by the generator to the piezotransformer. In addition, in the study, single piezo discharges are resolved in time using the method of pointwise integration. The spectrum and transient processes of the piezoelectric emitter are also analyzed using a spectrum analyzer, and the energy of a single piezodischarge is estimated. The research results showed that the most advantageous form of the applied voltage, from the point of view of energy efficiency, is a triangle when used both on the first and second harmonics of the piezotransformer, and the most efficient form of the applied voltage is a rectangular waveform, while a sinusoidal waveform signal is intermediate between the efficiency and performance of piezo discharges. It was also noted that despite the fact that the 2nd harmonic has a larger output voltage amplitude and quality factor, it is ineffective in terms of generating piezo discharges. The obtained results of the study can help in the development and optimization of portable and small-sized cold plasma sources