Development of metallized polypropylene capacitor reliability in pulse power systems

The advancement of the Army´s electronic lethality and survivability programs requires energy dense capacitors that are capable of being discharged at a rate greater than 20 kA/μs, and can sustain a voltage reversal of 20% of the rated charge voltage. The electrical and mechanical stresses of these requirements inherently cause capacitance loss during the discharge of the capacitor under test. The Army Research Laboratory (ARL), in conjunction with General Atomics (GA), has been working to develop state of the art metalized polypropylene (MPP) capacitors that can withstand the stresses of operating in pulse power systems. This paper will discuss the pulse power test results of various MPP capacitors developed by GA and evaluated by ARL with the goal of maintaining 90% capacitance after enduring 10 charge and discharge cycles where the discharge occurs within tens of microseconds and the peak currents exceed 100 kA. Over the past decade design advancements have been made that yield MPP capacitors with long DC life and high energy density but are also capable of discharge currents and rise times typically reserved for discrete foil capacitors.