IEEE Access (Jan 2019)
Control of e-CVT to EV Mode Transition on Braking Deceleration Condition for a Compound Power-Split Hybrid Electrical Vehicle
Abstract
The braking deceleration process of a compound power-split hybrid electrical vehicle is often accompanied by the switching process from electronic-continuously variable transmission (e-CVT) hybrid mode to pure electric mode. To reduce the impact of engine shutdowns on the powertrain, and improve the ride comfort of the vehicle, this study proposes a mode transition coordinated control strategy for the braking deceleration process of a compound power-split hybrid system. First, a powertrain dynamics model and resistance torque model of the engine shutdown process are established. Second, the driver's intention is identified, and the braking deceleration process is analyzed. Subsequently, the mode transition coordinated control strategy of e-CVT hybrid mode to pure electric mode is proposed and designed to distribute the output torque of each power source reasonably. Specifically, the optimal speed trajectory of the engine when it is dragged is designed based on a dynamic programming algorithm and is tracked with a model predictive control algorithm. Simulations and tests on a dynamic performance test bench show that the established control strategy can reduce the longitudinal jerk of the vehicle under the premise of satisfying driver braking demand. This effectively improves the ride comfort of the vehicle during mode transition.
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