Integration of Onboard Batteries and Supercapacitors Based on the Multi-Source Inverter for Light Rail Vehicles

Light rail vehicles with onboard energy storage systems have gained increasing interest due to higher efficiency and lower or null local emissions in catenary-less operation. Their traction circuit conventionally employs inverters to drive the traction motors and DC/DC converters to manage the onboard sources. Recently, the concept of multi-source inverter (MSI) was introduced for single-stage integration of AC loads and multiple DC sources without. This paper evaluates the feasibility and attractiveness of the MSI for single-stage integration of batteries and supercapacitors to the traction motors in a catenary-less tramway vehicle. The configuration of the MSI-based hybrid energy storage system is detailed. Numerical simulations are carried out to assess its performance over a typical driving cycle. Furthermore, the proposed architecture is compared to a standard configuration employing a DC/DC converter to control the supercapacitors, with focus on power losses and volumes of the converters and DC sources.