**2. Modeling**

In this research, a simulation model was created with Matlab/Simulink that included a vehicle, TMH transmission system, internal combustion engine (ICE), motor/generators (M/Gs), battery, and controller, as shown in Figure 1. With the United States FTP-75 (EPA Federal Test Procedure) of urban and highway driving cycles, the vehicle model could estimate the torque and power required for driving. The controller module (Controller) determined the transmission mode switching and the optimal output torques of the engine and M/Gs. The transmission module simulated the torques and speeds of the two motor/generators. The battery module would simulate the battery's state of charge (SOC) and battery charge and discharge status. These modules are presented in the following sections.

**Figure 1.** Simulink model of two-mode power-split hybrid system.
