Research Of Nanosecond Pulser For PEA Measuring System

With years of development, pulse electro-acoustic(PEA) method has become awidely used method for space charge measurement. PEA method is a criticaltechnology to promote the research of electrical characteristics of dielectric materials.Nanosecond pulser is an important part of PEA measuring system as the resolutionand sensitivity of the PEA measuring system are determined by pulse width and thethickness of piezo-electric sensor.This study designed main circuit of pulser with single transmission line pulseforming principle. The pulser’s characteristics and requirements are suit for PEAmeasuring system. The main circuit’s high-voltage DC source was built by switchingpower supply circuit and used mercury relay as discharge switch. This study givennot only the selection process of key components of the pulser, but also analyzed anddesigned the control circuit of high-voltage DC source and discharge switch.This study analyzed the influence to the output waveform of different matchingimpedances and different stray inductances by Multisim software. The pulser circuitmodel connected with load was built to verify the connection design. This study alsoverified the design of the control circuit of high-voltage DC source and dischargeswitch by Simulation.Based on the analysis of simulation, this article built the main circuit of thepulser. The influence to the output waveform of matching impedance, groundingmethod and transmission line material was investigated by actual measurement. Bythis way the design problems were found and settled. Finally a pulser which couldoutput pulse square waveform in good shape was obtained. The waveform’s pulseamplitude was0~1kV tunable, pulse width was50ns and it’s rising edge was4ns.In order to improve the pulser’s applicability in the PEA measuring system, it isvaluable to research the technique to shorten the rising edge and increase the pulseamplitude. To shorten the rising edge, this article analyzed the principle of correctivecapacitor and it’s calculation, built model with Multisim software to verify the corrective effects. To increase the pulse amplitude, this article analyzed the principleof Blumlein transmission line, built artificial pulser circuit model based on Blumleintransmission line with Multisim software.