The Structure Design Of The Conversion Unit And The Power For The Electro-pneumatic Inverter

Electro-pneumatic inverter is a kind of equipment that converts electric signal to pneumatic signal, and is the essential device in many automatic process control systems. Piezoelectric electro-pneumatic inverter is an improvement of the membrane electro-pneumatic inverter which is produced by Dalian University of Technology. Based on converting principle of nozzle-flapper structure, it uses a piezoelectric ceramic composite plate as actuator. Thanks to the breakthrough in principle, its structure is simple and it's easy to control.The thesis mainly contains four parts as following. Firstly, converting characteristic of the electro-pneumatic inverting device is researched. Secondly, optimization design on the inverter's mechanical structure is realized. Thirdly, inverter's intelligence control system is redesigned. Finally, a two-wired piezoelectric ceramic driving power is designed.Using FLUENT, optimum design of the pneumatic path structure and the nozzle of the inverter is achieved, the performance of the nozzle-flapper structure is improved and optimum design of the mechanical structure of the inverter is achieved, which reduces the volume of the inverter enormously.The control system of the electro-pneumatic inverter is redesigned, which kernel is MSP430F149 with super low dissipation. The system adopts the analog and digital closed loop control and uses the techniques of software filter and digital PID control. Control intelligence, diagnose intelligence and protection intelligence are the remarkable characteristics of the system. It meets the requirement of the two-wired low dissipation instrument, improves accuracy and reliability of the control system greatly. Two-wired piezoelectric ceramic driving power is designed, and the experiments demonstrate that the power can supply the control system and achieve the anticipant requirement.Through the static test of the inverter device and the operation of the whole set, the results show that the structure design of piezoelectric electro-pneumatic inverter is reasonable, its performance is reliable, and anticipant requirement is attained.