Design Of Piezoelectric Driver Based On Dds

Pipelines are commonly used in daily life and industry, and often transmit high-temperature high pressure flammable explosive toxic materials. So the safety of the pipeline is very important. In order to guarantee the safe operation of the pipelines, which nondestructive testing technology is used is the key. Ultrasonic guided wave detecting technique is widely used, because the sound field transmits throughout the wall, testing distance is long and high sensitivity. At the same time, piezoelectric driving technology has also been more and more concerned. Piezoelectric driver drives piezoelectric ceramic to generate ultrasonic guided waves, so the quality of the piezoelectric driver effect on the detection directly and greatly. So the study of piezoelectric driver has important practical significance and great prospect.As the dispersion and multi-mode properties of the ultrasonic guided waves while propagating through the pipeline, piezoelectric driver must has high-voltage high-frequency output capability arbitrary waveform capability and arbitrary window function modulation capability.This dissertation is based on the propagation characteristic of the ultrasonic guided waves, use DDS FPGA and USB communication technology, to achieve a high frequency, high voltage, arbitrary waveform, arbitrary window modulation, burst function, portable, low-cost, extensible, easy used piezoelectric driver. The work the author has done is as follows:(1) Analysed the propagation characteristics of ultrasonic guided wave, and analysed the property of piezoelectric ceramic, according to the high-frequency and high-voltage output requirement of driving piezoelectric ceramic and according to the arbitrary waveform arbitrary window function modulation requirement of ultrasonic guided wave detection, designed the block diagram.(2) Designed and developed the hardware of the system. Including USB communication circuit, microcontroller communication and control circuit, FPGA circuit, D/A circuit, filter circuit, instrumental amplifier circuit, and high-voltage power amplifier.(3) Designed and developed the software of the system. Including GUI on PC, communication and control program on microcontroller, and DDS hardware program on FPGA.(4) Tested the system. As the results show, the system can provide a voltage greater than 100V. a frequency from 75Hz to 195.31KHz output. Equipped arbitrary waveform, arbitrary window modulation, burst function and so on. Satisfied the requirement of driving piezoelectric ceramic and the requirement of ultrasonic guided wave pipeline defect detection.