Increasing environmental issues and energy crises led to rapid developments of hybrid electric vehicles, especially the planetary hybrid powertrain system (PHPS). This paper presents a comprehensive review of the PHPS, focusing primarily on contributions in the aspect of configuration, classification and comparison. In this work, a new classification method for PHPS architectures is proposed according to the number of electric motors (EMs). In addition, two kinds of PHPS, in the new

more »

... the new classification framework, are extensively emphasized in terms of its architectures, advantages and disadvantages. Furthermore, the port diagrams of representative architectures are presented to provide an intuitive method for power flow representation. Finally, a conclusion is made to provide an insight for developing PHPS as well.