tailieunhanh - Electric Vehicles Modelling and Simulations Part 14

Tham khảo tài liệu 'electric vehicles modelling and simulations part 14', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Predictive Intelligent Battery Management System to Enhance the Performance of Electric Vehicle 379 Vehicle model The EV model represents a series of mathematical equations representing the characteristics of the identified EV components in Figure 3 and the forces applied to the vehicle as depicted in Figure 12 The earth s gravitational force imposes a force Fg on the vehicle. Fg is derived from Newton s second law where a body of mass m endure an acceleration a resulting in an applied net force F. F mg 4 The gravitational normal force applied to the vehicle shall take into consideration the slope angle 0 when vehicle is moving uphill or downhill. Fgz mgCosỡ Fgx mgSinỡ In order to move the vehicle a wheel force Fw is applied on the wheel. Fw is the resulting force from the generated torque in the electric motor applied to the vehicle s wheels through a gear box with a fixed differential ratio. Fw is then represented as the ratio of the torque applied to the wheel Tw to the wheel radius rw. 77 _ w Fw ----- Tw When vehicle is moving the aerodynamic drag force Fd is created. Fd depends on the air density p the vehicle frontal area Av the drag coefficient Cd and the vehicle velocity Vv. 1 Ft 2 CtpVv2 Av 380 Electric Vehicles - Modelling and Simulations The contact surfaces between the vehicle s wheels and the road results into a friction force Ff. The product of the friction coefficient Pl and the vehicle s gravitational force Fg results in the corresponding frictional force Ff. Ff 1 T The total force acting on the vehicle Ft is the sum of all applied forces on the vehicle in the driving direction. Ft Fw - Fx - Fd - Ff The acceleration of the vehicle is determined by the torque applied to the wheels. The wheel torque Tw is the product of the E-motor torque Tem the gear box ratio Gb Tw emGb The acceleration of the vehicle av through the application of Newton s second law is the ratio of the total force acting on the vehicle to the mass of