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To further improve the comprehensive operating performance of the single motor hybrid electric vehicle, a single motor hybrid powertrain configuration with dual planetary gears (SMHPC-2PG) design is proposed in this paper. By adopting a topology design method that characterizes the constraint relationship between power resource components and planetary gear (PG) nodes, all feasible configuration candidates based on the basic configuration scheme are systematically explored, and dynamic models of configuration candidates are automatically generated. The optimal fuel economy and dynamic performance for configuration candidates are simulated by applying the global optimal control strategy based on dynamic programming (DP). Results of this study demonstrate that SMHPC-2PG with excellent operating performance can be screened out by this method.

At present, the regenerative braking control strategies for hybrid electric vehicles equipped with continuously variable transmission (CVT) mainly focus on improving the regenerative braking efficiency. But the influence of dynamic change of the CVT ratio is not considered with regard to the intended braking effect. For a CVT ratio control strategy based on steady-state optimal efficiency, the performance of motor-only braking and engine/motor combined braking modes are analyzed. The analysis of these modes shows that actual braking strength deviates from that required during the dynamic braking process. After analyzing the dynamic characteristics of a transmission system, a CVT ratio control strategy based on the limitations of the ratio rate of change is proposed, with the use of a discrete exhaustive optimization method. The simulation results show that, under a variety of braking conditions, the proposed regenerative braking control strategy can make the actual braking strength follow the requirements and recover more braking energy.

Increasingly strict emission and fuel economy standards stimulates the researches on hybrid electric vehicle techniques in automobile industry and one of the most important techniques is the design of powertrain configurations. In this paper, a theoretical design methodology for hybrid electric vehicle powertrain configurations is proposed to find the configurations with excellent performance in a large pool of configurations. There are two main parts in a powertrain configuration, power/coupling devices (engine, electric machine, wheel and planetary gear set) and mechanical connections between these devices. Different connections will lead to the configurations having different performance. This paper divides all connections in configurations into three categories and a novel matrix representation method is developed to express these kinds of connections so as to reflect system dynamics and physical structure of configurations. With the support of the matrix representation method, configuration selections from large pools can automatically be completed by computer and manually calculation and comparison can be avoided, which saves much energy and time. Finally, the proposed method is vigorously verified by simulations.