The Research On Key Technology Of Corona Test Circuit

The corona performance of the enameled wire directly determines the service life of the variable frequency motor,but it is difficult to meet the ordinary pulse power supply because of its need for high-pressure,high-speed pulse and other conditions.This article for the enameled wire corona test with the power supply output pulse requirements,designing a corona test circuit,the main contents are as follows:(1)Design of High Voltage and High Speed Pulse Circuit.This paper uses H bridge as the form of circuit,and takes insulated gate bipolar transistor(IGBT)as the H bridge switching device.Using the high-voltage power supply for large and low resistance of the capacitor,then the capacitor provides transient current charge on the capacitive load by the H bridge,thus achieving rapid changes in voltage across the load.(2)Determination of Main Circuit Parameters for Corona Test.On the basis of the anti-corona test technology,by analyzing the charging and discharging process of the capacitive load in the corona test,the relevant parameters of the corona test circuit's main circuit and the 'parameters of the IGBT are determined,and the design of the main circuit is finally completed,after being verified by circuit simulation;the use of gate resistance of the resistance can be appropriate to adjust the pulse rise/fall time.(3)Design of Corona Test Isolation Drive Circuit.According to the requirements of anti-corona test circuit isolation drive,compared with other isolation drive mode,modeling analysis the coupling between high-voltage part of the circuit and isolation drive circuit,finally designing for this issue of isolation drive circuit,and the circuit board layout is optimized to further improve the isolation drive anti-jamming capability.(4)Design of Circuit Protection Circuit for Corona Test Circuit.Analysis of corona test circuit protection circuit of the particularity,and for the gate overvoltage and instantaneous high dv/dt caused by misoperation and other issues,coupling with a reliable protection circuit to ensure that the IGBT tube is not burned out,to safe and reliable operation.Finally,the corona test circuit is debugged and analyzed,and the waveform of the output pulse is tested.The output voltage of the corona test circuit is bipolar square wave,the voltage peak-to-peak value is 3kV,the voltage rise time and the falling time are 100ns,the pulse duty ratio is 50%.The experimental results show that the main technical indicators of the test circuit meet the enameled wire corona test with the pulse power supply standards.This technology provides the experimental basis for the design of the enameled wire corona resistance test device.