Control of Dual Mode Power Split Transmission for a Hybrid Electric Vehicle

Motor control algorithm for a dual power split system is proposed for hybrid electric vehicles (HEV). The dual mode power split system consists of an electric variator, MG1 and MG2, and three planetary gear sets. In order to develop the control algorithm for the best fuel economy, the dual mode PST is analyzed by network analysis. From the network analysis results, it is found that the dual mode PST efficiency decreases in the speed ratios where the power circulation occurs, and it is required that the ICE needs to be operated on the speed ratio region where the powertrain efficiency is relatively high. Using the dynamic models of the HEV powertrain, a motor control algorithm to obtain the high system efficiency is designed by inversion-based control. In order to evaluate performance of the control algorithm, HEV simulator is developed using Cruise and MATLAB Simulink. It is found from the simulation results that the motor control algorithm proposed in this study provides improved fuel economy since the motor control is able to provide the ICE operation on the speed ratio range, which gives relatively high powertrain system efficiency.