Research On Driving Power Supply Of Piezoelectric Dispensing Valve Based On State Feedback

Piezoelectric jet dispensing technology as an important technology of microelectronics packaging field frontier is the key research of high speed and high precision fluid dispensing technology at home and abroad.However,countries dominated by Germany,Japan,and the United States have basically monopolized the high-end piezoelectric jet dispensing technology from the valve body of the piezoelectric dispensing valve to the dispensing valve controller.This article combines the technical accumulation of the research group in the piezoelectric dispensing valve body,aiming at the lack of precision of the existing commercial dispensing valve controllers in piezoelectric ceramic displacement,firing pin displacement,and even glue point control,facing the control needs of high-speed and high-precision jet dispensing of piezoelectric dispensing valves,developing a piezoelectric ceramic drive power supply based on the displacement and state perception of the striker,and strive to further improve the dispensing accuracy of the piezoelectric jet dispensing technology from the drive power supply.The main research contents of this disseration are as follows:(1)A method is proposed to further improve the accuracy of dispensing by using the piezoelectric ceramic drive power of the dispensing valve with state feedback.The closed-loop feedback system is constructed through the displacement of the striker and the voltage and current detection of the piezoelectric ceramic.The dynamic input of various parameters of the driving power supply is used to compensate for the nonlinearity of the piezoelectric actuator and the displacement amplification structure,so as to realize the high-speed and high-precision driving of the piezoelectric dispensing valve.(2)Analyze the basic theory and characteristics of piezoelectric ceramic drive,study the nonlinear dynamic model of the dispensing valve,and obtain the internal connection from the drive power,the piezoelectric stack,and the displacement amplification mechanism to the consistency of the dispensing points.Simulate the dynamic model and analyze the control requirements of its response characteristics.(3)A power amplifier stage based on the theory of Class D power amplifier is proposed,and its working characteristics are studied to improve the output capacity while reducing noise interference.The structure topology of a fourth-order trapezoidal LC low-pass filter is proposed.Based on the working characteristics of the piezoelectric dispensing valve,a bootstrap boost circuit based on the principle of self-excited oscillation is constructed.A PWM waveform generator based on STM32 is designed,the PWM modulation waveform of the trapezoidal wave is generated by the software method,and the dead time of the driving power is studied at the same time.(4)Carry out the research of displacement feedback control theory,and propose a nonlinear displacement feedback control strategy for the dynamic system of the dispensing valve,and establish a simulation model to verify the effectiveness of the control strategy.Design the displacement detection module,and build a test platform to test the performance of the displacement detection module,at the same time,combined with the microprocessor to design the closed-loop state feedback control system of three state detection of striker displacement detection,voltage detection,and current detection.(5)Build the electrical performance test system of the piezoelectric ceramic drive power supply to conduct steady-state ripple noise,linearity,stability,dynamic characteristics,and trapezoidal wave output tests.After testing,the ripple noise,steadystate drift,and linearity error of the designed driving power supply are less than 1%.The transient output current can reach 11.88A,and the output amplitude can reach 120V with any parameter adjustable regular trapezoidal wave.At the same time,the injection performance test system of the driving power supply driving dispensing valve is built,and the hot melt adhesive is selected for injection test.Comparing the difference in the consistency of the glue points between the driving power supply with state closed-loop feedback and the commercial power supply,the results show that under the same test conditions,the volume consistency error of the commercial valve controller to control the injection of hot melt adhesive is±2.3%,while the volume consistency error of the driving power test developed in this disseration is±1.05%,which verifies the advantages of the drive power developed in this disseration in the precision drive of the valve.