PV Battery Charger Using an L3C Resonant Converter for Electric Vehicle Applications

In electric vehicles with rooftop PV panels, the solar irradiance and surface temperature can affect their performance and output voltages (e.g., V-pv = 24-45 V-dc). In these systems, the maximum energy must be extracted from the variable input voltage (PV panel), boosted by different gains, and stored in high-voltage battery packs. Furthermore, depending on the battery state of charge, the charger should operate in constant voltage, constant current, or constant power modes, all the way from complete discharge condition, up to the charged floating voltage phase (V-bat = 230-430 V-dc). This combination of the variable PV input voltage and different states of charge creates a significant regulation challenge for the converter. In this paper, a high-efficiency fourth-order L3C resonant converter is proposed with an extreme voltage regulation capability that can effectively extract the maximum power from the PV panels and respond to the battery states of charge at different voltage and current levels. The experimental results from a 350-W prototype prove the features of the proposed L3C resonant converter and demonstrate its ability to track the maximum input power while responding to the battery various states of charge.