Study On Overload Characteristics Of MPP Capacitor

Currently, the compact pulsed power devices for single use have attracted more and more attention. Because of single use, more compact pulsed power devices are possible. The pulsed capacitors due to their safety and reliability are the main primary energy sources for pulsed power devices. Especially, the developments of MPP capacitor technology provide great convenience for building compact primary energy system. The MPP capacitor at rated voltage and rated current has a certain life. If the capacitor is designed to work reliably once or several times in over-voltage and over-current status, the energy density can be improved greatly, this method can be applied in building an extremely compact primary energy in pulsed power devices. This dissertation has investigated the overload characteristics of the MPP capacitors. The results make a good foundation for conducting compact primary energy sources operating at once or several times. The main content of the dissertation are as follows:Firstly, the developments and characteristics of MPP capacitors are described, the related knowledge of MPP capacitor is introduced, the research of overload experiments in foreign is briefly summarized, and the test methods of capacitor parameters, temperature, high voltage and pulse current of overload experiments are briefly introduced.Secondly, the overload characteristics of capacitor units under different temperature are studied in detail. The results of temperature experiment show that the capacitance with temperature change rate of MMJ4-6.6 capacitor units is k_C≈-1.2×10^-3μF/°C at -45℃⁶0℃. The overload energy storage density is more than 1.8 times of the rated energy storage density at -45℃⁶0℃. According to the results of overload discharge experiment, the discharge capability of these units is more than 100kA/kJ. The leakage experiment indicates that the charging current of MMJ4-6.6 capacitor units must be larger than 500μA. These provide an important experimental basis for the design of compact primary energy sources.Lastly, the overload characteristics of capacitor units in series-parallel connection are researched preliminarily. The results of withstand voltage experiment show that the voltage-reliability confidence lower limit of MKMJ3-50 capacitor units is 0.81 and the confidence level is 0.7 at 4kV. The results of overload discharge experiment show that the single reliable discharge (30kA) reliability of MKMJ3-50 capacitor units is 0.94 at the confidence level of 0.7. Based on the results of overload discharge experiments of capacitor units in series-parallel connection, the discharge current capacity of MKMJ3-50 capacitor units reaches 48kA for single use. These make a good foundation for conducting compact primary energy sources operating at once or several times.