High-efficient, ultra compact integrated electric drives for tomorrow’s alternative drivetrains Mojgan Nikouei-Harnefors, Funding period: 2013-08-01 – 2015-03-31 Dept. Electrical Energy Conversion, KTH Royal Institute of Technology Swedish Hybrid Vehicle Centre (SHC) Granted funding: 1.58 MSEK

Motivation

Integrated drives (examples) Volvo ReCharge

Project overview

Project overview

Stacked polyphase bridges (SPB) Power converter Electric machine Battery

Machine considerations Fractional-slot concentrated-winding (FSCW) - Short end-turns - Low cogging torque - High slot filling factor (segmented stator) Challenges - Suitable slot/pole combinations to obtain: - High fundamental winding factor - Low rotor losses - Ease of integration (identical converter sub modules) - Fault tolerance to handle a converter sub module fault

Control considerations Converter sub module - Current control - Field weakening Master control - DC-link voltage control and communication (ongoing work) - Fault handling (ongoing work)

Technical summary New method of machine and converter integration New converter topology (SPB converter) Low voltage Si MOSFETs provide very high efficiencies and allows reasonably high junction temperatures Future GaN may enable even lower losses Low voltage, high switch frequency → very small, non-electrolytic capacitors Potential fault tolerance (limp home) is “in built” 9/31

Future/ongoing work Refine the design of the electric machine Develop a robust control technique Evaluate tolerance to faults Investigate power electronic manufacturing techniques Full-scale prototype evaluation Identify suitable applications for the converter topology 10/31

High-efficient, ultra compact integrated electric drives for tomorrow’s alternative drivetrains Mojgan Nikouei-Harnefors, Funding period: 2013-08-01 – 2015-03-31 Dept. Electrical Energy Conversion, KTH Royal Institute of Technology Swedish Hybrid Vehicle Centre (SHC) Granted funding: 1.58 MSEK