The self-healing characteristics of metallized film capacitors under DC voltage have been studied extensively by scholars.
A significant increase in the efficiency of modern metallized filmcapacitors has been achieved by the application of special segmented nanometer-thick electrodes. The proper design of the electrode segmentation guarantees the best efficiency of the capacitor's self-healing (SH) ability.
As a result, the geometric optimization of self-healing capacitor should be studied further. To investigate the geometric optimization of self-healing capacitor systematically, the temperature distribution simulation model of self-healing power capacitors with different elements orientations are formulated in Fluent15.0.
Currently, self-healing power capacitors are mainly applied in low voltage cases. This is because that the geometry of the self-healing capacitor is not the most optimized solution. If the high voltage is applied, the temperature rise is significant. The lifetime of self-healing power capacitor is shortened.
Metallized film capacitors (MFCs) are reliable because of the self-healing feature and are widely used in the sub-module of the modular multilevel converter (MMC-SM). To reflect the practical working condition of MMC-SM, the self-healing characteristics of MFC in MMC-SM under DC and AC superimposed voltage with harmonics were studied in this paper.
Unfortunately, this mechanism can be dificult to control, and in the worst case, a run-away process can result, causing the destruction of the entire capacitor in short order. To avoid this, KYOCERA AVX developed a controlled self-healing process in 1974 based on the segmentation of overall capacitance into elementary cells protected by fuse gates.