The Study Of Dual-motor Control Algorithm Based On The Electrical Variable Transmission For Hybrid Vehicle

New energy vehicles is gradually well received in the automotive industry, which include pure electric vehicles, hybrid electric vehicle and fuel cell vehicles.The Hybrid vehicle is developing rapidly for its long travel distance and good fuel economy, especially in the domain of city bus. Nowadays the Toyota hybrid system——Electrical Variable Transmission(EVT) hybrid system is more successful for its mass production. In this paper EVT for city bus will be discussed.The EVT configuration studied is composed of two motors(MG1, MG2) and double Planetary gear system.First of all,working principle of EVT is introduced including analysing the working state of the engine and two motors in different mode.The method of lever model is used to get the relations of the rotational speed and torque between engine and motors.Then the requirements of the system for motors in different mode could come out.On that basis,feedforward and feedback control algorithm of MG1 and torque compensation algorithm of MG2 are proposed.Motors are the key components in EVT working as the power unit and the mode switch actuator.Therefore the permanent magnet synchronous motor and its control system is discussed. Then the Field Oriented Control(FOC) and flux weakening control of motor are introduced.To realize the process of FOC, pulse width modulation technology is analyzed with the built Simulink simulation model.The simulation results show that the motor control system has good dynamic response and flux weakening control expanding the rotational speed and torque output capacity of the motor.Besides,the EVT simscape model and its control algorithm model are built,which is integrated with the motor control system.By the whole system simulation, results show that the control algorithm can make the engine follow target working point and the torque compensation algorithm of MG2 can reduce the impact during mode conversion.