A Novel Estimation Method for Equivalent Series Resistance of Film Capacitors Considering Frequency Characteristics

Capacitors have been widely utilized for power converters in renewable power generation. Their equivalent series resistance (ESR) is a critical parameter for estimating capacitor lifespan and aging. This study proposes a novel ESR estimation method specifically for low-ESR, low-capacitance capacitors such as film capacitors. Simulations and experimental results under various conditions demonstrate that the proposed method more accurately estimates ESR values, compared to the conventional methods. In addition, frequency characteristics of ESR are estimated under actual operating conditions, which has not been considered in previous literatures.