Motor Control for Power Variator in a Hybrid Electric Vehicle

Motor control algorithm on how to operate the internal combustion engine (ICE) is proposed for hybrid electric vehicle (HEV) with EVT which consists of a power variator, MG1 and MG2, and planetary gear set. From the network analysis results, it is found that the EVT efficiency decreases in high speed ratio region due to the power circulation, and it is required that the ICE needs to be operated on the speed ratio region where the powertrain efficiency is relatively high. The motor control algorithm to operate the ICE is designed by inversion-based control. In order to evaluate performance of the control algorithm, HEV simulator is developed based on the dynamic models of the HEV powertrain using Cruise and MATLAB Simulink. It is found from the simulation results that the motor control algorithm proposed in this study shows improved fuel economy compared with the conventional control since the power variator motor control is able to provide the ICE operation on the speed ratio range, which gives relatively high powertrain system efficiency.