Research And Design Of High Frequency And High Voltage Power Supply For Underground Cable Fault Detection

In order to meet the needs of urbanization construction,the application of urban underground cable is becoming more and more extensive.When the underground cable fault occurs,equipments which are able to quickly detect the cable fault and the fault point location have become the urgent demand of the current enterprose production and city life.As an important part of cable fault detection equipment,high voltage power supply is used to drive the fault cable to generate echo response,and then the receiver responds to the received signal to analyze and process,so as to locate the fault cable fault location.Aiming at the shortage of the traditional high voltage pulse power supply of single function,large volume,unable to realize the wireless operation,this paper has developed a power supply which can achieve 1 DC high voltage output and 2 different frequency AC high voltage output,to achieve the positioning of the underground cable fault point and the path of the cable fault detection.The high voltage power supply has the characteristics of small volume,and can be interconnected with mobile phone APP through Wi Fi wireless communication.The 10.1 inch TFT-LCD touch screen is used for human-machine interaction,which greatly improves the safety and practicability of the operation of the high-voltage power supply.In this paper,the demand of high frequency and high voltage power supply is analyzed firstly,and the overall implementation scheme of power supply system is put forward,including power circuit,auxiliary power circuit topology and control circuit design.Then the detailed theoretical modeling of DC power circuit topology of DC Buck converter preset pressure unit,the whole bridge converter unit of the lagging arm of a series diode ZVZCS phase-shift full-bridge converter as well as the power transmission unit of high-frequency step-up transformer design are analyzed.At the same time,the isolation of the full-bridge inverter drive unit power supply was discussed and the auxiliary power design method based on multi-winding output of the flyback converter was analysed in detail.Finally,the control circuit based on DSP28335 was discussed in detail.In order to verify the correctness and feasibility of the design scheme,a high-voltage power supply experimental platform was made.The experimental platform has good man-machine interaction interface,and it can communicate with mobile phone APP.By testing the functional modules of the experimental platform and the whole machine,the measured waveforms and data of all the key points of the power meet the design requirements of the project,which can achieve 0-30 k V adjustable AC/DC and high voltage output steadily.This paper has completed the design and debugging of the whole high voltage power supply which realized the digital control of high voltage power supply based on TMS320F28335 unified digital controller as the core.Through theoretical analysis and experimental verification,the power source is effective to be applied to underground cable fault detection.