Abstract:

An electric machine type with a dual-rotor structure called electrical variable transmission (EVT)
was proposed in hybrid electric vehicle (HEV) transmission application, whose speed difference of dual shafts is
detected in real time for its inner motor vector control. A detection method was developed based on salient outer
rotor variable reluctance (VR) resolver work with ring transformer, with the resolver-to-digital converter (RDC)
board based on AD2S1200 being built for the control system. The method can avoid defects such as signal
delay and error accumulation caused by traditional methods, which use two sensors to detect the dual shafts’
speeds and solve the difference thereafter. The results show that the method can be used in EVT’s speed
control systems.

Key words: hybrid electric vehicle (HEV), electrical variable transmission (EVT), speed difference, variable reluctance (VR) resolver, ring transformer