电容型脉冲电源续流震荡暂态特性研究

Research on transient characteristics of freewheeling oscillation of capacitive pulse power supply

电容型脉冲功率电源放电续流过程易在电容支路和续流二极管支路产生震荡,而震荡现象会造成续流二极管损耗及脉冲电容反向充电电压增加,影响续流二极管及脉冲电容的运行寿命。为此,首先建立了电容型脉冲电源续流放电过程解析模型,求解得到了电容和负载支路电流曲线,分析了续流震荡产生机理及震荡特性影响因素;然后,基于频域矢量匹配法,通过对工作频带范围的阻抗特性曲线进行拟合,建立了电容支路和续流支路杂散参数的宽频带等效电路,利用该模型表征续流震荡过程中杂散参数的瞬时变化规律,进而实现对续流暂态过程震荡幅值和周期的准确描述;最后,搭建脉冲放电测试平台,对脉冲电容放电电流波形进行了仿真和实验对比,验证了所建理论模型的正确性。

The capacitive pulse power supply is easy to oscillate in the capacitor branch and the freewheel diode branch.The oscillation phenomenon will cause the loss of the diode and the increase of the reverse charging voltage of the pulse capacitor,which will affect the operation life of the diode and the pulse capacitor.Therefore,an analytical model for the process of continuous discharge of capacitive pulsed power supply was established whereby the current curves of capacitor and load branch were obtained,and the generation mechanism of freewheeling oscillation and the influencing factors of oscillation characteristics were analyzed.And then,based on vector matching method of frequency domain,and through the work frequency band range impedance curve fitting,the broadband equivalent circuit of stray parameters of capacitance branch and freewheel branch was established,with which the instantaneous change rule of stray parameters during the freewheeling oscillation process was represented,thus realizing the accurate description of the oscillation amplitude and cycle of the freewheeling transient process.Finally,the pulse discharge test platform was built to conduct simulation and experimental comparison of capacitor discharge current waveform.The comparison results show that the proposed theoretical model is correct.