A New Integrated Onboard Battery Charger For Electric Scooters

In this paper a new DAB based bidirectional integrated onboard charger for electric scooters is discussed. Utilizing a single-phase matrix converter as a high-frequency AC-AC converter, a high-frequency transformer as isolation, and incorporates semiconductors from the onboard traction inverter as rectifiers to efficiently charge the low-voltage battery. For enhanced safety, high-frequency isolation safeguards the internal traction circuit. Additionally, the onboard electric motor is disengaged during the charging process to protect unintentional power flow. A design example implementing optimal Triple Phase Shift (TPS) modulation with 4-step switching, and minimum RMS current technique is showcased, featuring a 3kW power rating and benchmarking this rating against a conventional off-the-shelf external charger. This approach promises improved integration and convenience in electric scooter charging solutions.