Power Conversion Interface for a Small-Capacity Photovoltaic Power Generation System

A power conversion interface for a small-capacity photovoltaic power generation system (PPGS) is proposed in this paper. The proposed power conversion interface is composed of a DC–DC converter (DDC), a battery pack and a buck–boost inverter (BBI). The battery pack is integrated to the power conversion interface to store or release energy for smoothing the power fluctuation of the small-capacity PPGS. The battery pack is only activated when a large power change occurs in the photovoltaic array (PV array). The DC power, no matter whether is from the PV array or the battery pack, needs to be converted into AC power only by the BBI in the proposed power conversion interface. Moreover, the PV array charges the battery pack only through the DDC, which simplifies the power circuit and improves the power conversion efficiency. To verify the feasibility of the proposed power conversion interface, a hardware prototype is established for practical experiments

Auxiliary health diagnosis method for lead-acid battery

This paper proposes a health auxiliary diagnosis method for the lead-acid battery unit. The proposed method is based on Approximate Entropy (ApEn). Since ApEn can quantify the regularity of a data sequence and the discharging curve for a health lead-acid battery unit is smooth, the proposed method can detect the degradation of battery unit caused by the internal short, opening of internal shorted or cell undergoing reversal using the distorted discharging curve. Aging experiments for the lead-acid battery are developed to verify the proposed method. The experimental results verify that the proposed health auxiliary diagnosis method can diagnosis the degradation of battery unit caused by the internal short, opening of internal shorted or cell undergoing reversal.Lead-acid battery State-of-health Approximate Entropy Coulomb counting method Coup de fouet Sample Entropy