A 1.12 kW photovoltaic-integrated electric vehicle: Prototype development and application to a community bus

Integrating photovoltaics (PVs) into electric vehicles (EVs) is expected to significantly contribute to promoting renewable energy use in the transport sector. This study presents the development and application of our prototype PV-integrated EV with a PV capacity of 1.12 kW. The vehicle was designed to supply PV power directly to the inverter/motor and other onboard electronic devices while driving without passing through the battery, and to store PV power in the battery while parked. Two DC/DC converters, one equipped with maximum power point tracking (MPPT) and one without, were implemented to compare performance. The vehicle was deployed in an urban-rural, mountainous area in Fukushima, Japan, and operated on a 25-km round-trip route twice daily (50 km/d) for 140 days from September 2023 to August 2024 under various weather conditions. Results showed that the PV system supplied 13.5% of the energy required for the daily 50 km drive and improved electric efficiency by 3.9%. Performance analysis of the onboard PV system, focusing on DC/DC converters, suggested that using the MPPT-equipped DC/DC converter could increase output by about 1.25 times, potentially raising the PV supply rate to 14.8% and efficiency improvement to 4.3%.