Abstract: The topology structures and operating modes of two kinds of Hybrid Power Systems (HPSs) were compared to verify the feasibility of the HPSs and analyze the  operating characteristics, in which one is a typical ‘2-Mode’ parallel-series hybrid system, and the other is a novel Anti-Direction-Dual-Rotor (ADDR) electric motor based system. Simulation was made using a mathematic model of HPS developed in previous work for comparative analysis of the two systems for two typical load conditions, running with low power and accelerating with large power. The results show that both the two systems improve the ability to mechanically transmit power and minimize energy circulation of engine power conversion to electricity. The performance requirement of the ADDR electric motors is lower than that of the traditional ‘1-Mode’ system for the same required condition. Therefore, this HPS control leads to the reduction in the vehicle size, mass, and even the cost, though it is more complicated.

Key words:  hybrid power system (HPS), series-parallel power hybrid system, electric motor, comparative analysis, simulation