Dear all,
thank you for your comments on the energy model in SUMO. I am just internally answering my colleague Jan to his questions but think that you could be interested in some of my observations.
Despite bugs mentioned by Burford, their correction (that is certainly important in SUMO) will only slightly impacts our energy results for these reasons:
1.
Change of Rotational Energy << Change of Kinetic Energy
since the internal moment of inertial << mass of the vehicle (for example for our simulated trolleybus J_int = 0.03*mass)
2. The calculation of
the Curvature Energy Loss is applicated only 3 times per trolleybus No. 13 line circulation in simulation without surrounding traffic. The reason for such behavior is that the diff of route angle is not zero only at three time-steps of the simulation from total ca 5k.
3. Fortunately we use the default SUMO length
1 s of the time-step and therefore, the confusion of power [W] vs energy [Ws] vanishes. (It counts both for the bug in the constat power of aux system calculation and for the order logic of energy/power calculations in SUMO's emission/energy model).
Finally, the paper [
I. Sagaama, A. Kchiche, W. Trojet and F. Kamoun, "Proposal of More Accurate Energy Model of Electric Vehicle For SUMO] you mentioned proposes three changes for SUMO model
b. calculation of efficiency as \eta_bat*\eta_inv*\eta_mot
I don't understand the difference between such calculation in comparison with using only one constant eta, that can be precalculated of course using the above-mentioned formula.
Maybe in our case would be interesting to consider different values for the efficiency of propulsion using energy from battery (battery->inverter->motor) and from overhead wire (owhd wire -> inverter -> motor) but again fortunately these values are almost the same in practice.
a. using the proposed modified equation for calculation of the energy of auxiliary drives corresponds to the common approach in SUMO if the ambient temperature is 20°C
c. the modification of efficiency of regenerative breaking is already integrated into the SUMO
Best,
Jakub