Development Of High Voltage Frequency-modulated Power Supply Based On Phase-locked Technology

At present,the output voltage amplitude of the analog high-voltage frequency-modulatedpower supply is maximum when the working frequency of power supply is similar to the resonant frequency of the whole circuit made up of the power supply and the load.The output voltage of the power supply will drop sharply when the working frequency of the power supply deviates from the resonant frequency of the whole circui.The output voltage amplitude of frequency-modulated power will be very low at the frequency distant from the resonance frequency.If we use such AC power to do high voltage test,the frequency range of the output high voltage that meets the experimental requirements is narrow.Aiming at the problem of analog high voltage frequency modulation power supply,a high voltage frequency modulation power supply is developed in this paper.When the operating frequency of the power supply is regulated in a wide frequency range near the resonant frequency of the circuit,the output voltage of the power supply can not be reduced too severely,and the higher voltage amplitude can be output at the frequency distant from the resonance frequency.Thus,the power supply can output high voltage that meets the experimental needs in a wider frequency range,providing more experimental data for high-voltage experimental research.The steeper the amplitude frequency characteristic curve of the output voltage of the HV FM power supply,the more severely the output voltage drops when the power frequency deviates from the resonant frequency;the flatter the amplitude frequency characteristic curve of the output voltage is,the more gently the output voltage drops when the frequency of the power supply deviates from the resonant frequency.In this paper,a high voltage FM power supply which can be used in dielectric barrier discharge experiment is designed.The factors that affect the amplitude frequency characteristic curve of the power output voltage are investigated and analyzed in the whole circuit composed of the power supply and the load.It is proposed that how to regulate those factors to make the amplitude frequency characteristic curve of the output voltage flatter.Further more,it is also proposed how to choose the transformer winding method and the winding structure to change these factors so that the output voltage amplitude frequency characteristic curve becomes flatter.In this paper,the main circuit composed of the rectifier and filter circuit,the half bridge inverter circuit and the transformer is designed.Based on the importance of phase-locked technology to high voltage frequency modulation power supply,a phase-locked control circuit with CD4046 phase locked loop is designed.The control circuitrealizes the working frequency regulation function of the power supply by controlling the working frequency of the switch tube in the half bridge inverter circuit.In addition,the overvoltage and overcurrent protection circuit and soft start circuit are designed to improve the reliability of power supply operation.The HV FM power supply also has the function of measuring the amplitude and the frequency of the output voltage,and reduces the dependence on the expensive experimental installations such as high voltage probes and oscilloscopes.A high voltage FM power supply for dielectric barrier discharge experiment is successfully designed in this paper.The maximum output power of the power supply is 1k W,and the input voltage of the power supply is the power frequency AC 220 V voltage with the voltage fluctuation of no more than 10%.The output voltage amplitude is 2 to 20 k V and the frequency is adjustable from 5 to 20 k Hz.Finally,the actual load test proves that the power supply achieves the expected goal and meets the requirements of the experimental load.