Research on eco-driving strategies for supercapacitor trams

Focusing on the eco-driving for supercapacitor trams, considering traction/braking characteristics, trip operation time constraint, variable value of slope and power constraints of supercapacitor, a modified dynamic programming method was proposed with consideration the optimal manipulation derived from the maximum principle. Firstly, the system model was introduced, and an optimization problem was constructed. Then, eco-driving regimes of supercapacitor trams were analyzed based on the maximum principle. The state space of velocity trajectory was constructed integrating dynamic programming. Finally, the bi-section method was utilized to find optimized eco-driving speed profiles to satisfied the trip time constraint. Simulation results show that the better solve efficiency and quality can be obtained by the modified dynamic programming compared to the traditional dynamic programming. The high utilization rate of regenerative braking for supercapacitor trams increases the usage of electric braking condition and shrinks the usage of coast condition.