Clutch-to-Clutch Gearshift Control for Multi-Speed Electric Vehicles during Regenerative Braking Events

Electric vehicles with stepped automatic transmissions provide benefits for improve drive performance and lower energy consumption. To deliver the desired operational functionality of power-on shifting for all driving states, this paper presents a novel methodology for the achievement of power-on gear shifts during regenerative braking events in electric vehicles equipped with multi-speed transmissions. Separate algorithms are developed for upshift and downshift events, where the control of clutches is considered for both torque and inertia phases of these events. Consideration is given primarily to the delivery of negative friction torque through the clutches during the inertia phase of gear change. A multi-body dynamic model of a dual clutch transmission equipped powertrain is then developed, including a DC equivalent motor model and piecewise clutch models, to evaluate the performance of these clutch control algorithms. Results of these simulations demonstrate the effectiveness of these shift control strategies and the capacity to maintain brake torque to the road during shift events.