DC-Link Capacitance Estimation for Power Converters Using Integrated PCB Rogowski Coils

This is the authors' abstract. We don't add key points for this paper.

Capacitance is a key electrical parameter of capacitors in power electronic converters, and its estimation is important for the stable operation of the converters. This article presents a small printed circuit board (PCB) with Rogowski coils for measuring ripple voltage rate (dv/dt) and ripple current in an online and contactless manner to estimate the capacitance. Electric field coupling is utilized to achieve dv/dt measurement capability in the Rogowski coil-based current sensing solutions. The coils and processing circuit are designed to achieve high sensitivity and low noise for accurate low-frequency band measurements. The wireless module is integrated to sample and transmit the result without any wiring. Through a case study of an aluminum electrolytic capacitor (Al-cap), the proposed method has been demonstrated to be applicable to capacitors in converters. The small PCB is nested on the capacitor terminals, and the accuracy of the presented method is verified through offline, online-based single-phase inverter, and degradation emulation experiments.