EXPLORING THE EFFECTS OF A VOLTAGE BASED SHIFTING ALGORITHM ON A HYBRID-ELECTRIC VEHICLE LIMITED BY BACK EMF

Open Access
Author:
Brown, Kyle
Area of Honors:
Electrical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Gary L Neal Jr., Thesis Supervisor
  • Julio Urbina, Honors Advisor
Keywords:
  • hybrid-electric vehicles
  • simulation
  • MATLAB
  • Simulink
  • Penn State Advanced Vehicle Team
  • Electrical Engineering
Abstract:
In hybrid vehicle architectures where the engine is directly coupled to the motor, the two components must share the same speed. In a vehicle where the motor speed is limited by back EMF issues, this can greatly limit vehicle performance. This thesis explores a method of improving vehicle performance in such hybrid architectures. The maximum speed of the motor varies with voltage. A real-world bench test is conducted to map the top speed limits of this motor at different voltages. With this real-world data, an algorithm is designed that controls vehicle shifts to maintain higher engine and motor speeds as much as possible. The algorithm is tested using a Simulink vehicle model of the hybrid vehicle architecture described above. Testing shows that the algorithm successfully maintains the motor speed below its specified limit at all times. Simulations also show an improvement in vehicle acceleration using the new shifting algorithm. The vehicles IVM-60 mph time is decreased by 0.04 to 0.08 seconds, and its 50 – 70 mph passing times is decreased by 0.26 to 0.30 seconds.