Diagnosis and Compensation of Power Capacitor Deterioration to Improve Performance and Safety of PV Inverters

Inside power devices, electrolytic capacitors for power are essentially used for AC/DC linkage for temporary energy storage and filter functions such as voltage smoothing. In particular, as the use of power converters has rapidly increased in the field of new and renewable energy such as PV power generation and the demand for electric vehicles has increased, the use of electrolytic capacitors has increased, and electrolytic capacitors are responsible for most accidents in power conversion devices. Therefore, in this paper, we analyzed the correlation between voltage and capacitance through a capacity-specific deterioration test for DC capacitors of PV inverters that are commercially available. In addition, we studied a compensation module and related algorithms that can detect the degree of electrolytic capacitor deterioration and compensate for the deterioration. Through this research, we aim to improve the safety of PV power generation systems by compensating for the deterioration of electrolytic capacitors and maintaining the continuous performance of PV inverters.