Modeling of ESR in metallized film capacitors and its implication on pulse handling capability

• A model to calculate ESR of capacitors with consideration of the contact status is presented.
• ESR at low frequencies is effective to reflect contact.
• Capacitors with smaller ESR at 100 Hz enjoy better pulse handling capability.

Metallized film capacitors (MFC) are widely used in pulsed power systems and power electronics applications. The pulse handling capability of MFC is one of important performances and drastically depends on the quality of contact states between the spray and metallization. The equivalent series resistance (ESR) is a significant parameter to the capacitor. This paper presents a model to calculate ESR with consideration of the end contact status. This model shows that ESR at low frequency (∼100 Hz) is more efficient to reflect the end contact status than that at high frequencies (∼10 kHz). Lifetime experiments are designed to demonstrate that MFC with significantly lower ESR enjoy longer pulse lifetime and better pulse handling capability. Thus measured at low frequency (∼100 Hz) can be regarded as a parameter to reflect the disconnections of weak contact in high current densities applications and to evaluate the pulse handling capability.