Simulation method for determining traction power of ATN–PRT vehicle

Abstract

The construction of Personal Rapid Transit (PRT) vehicle made within the framework of Eco-Mobility project has been described in the present paper. Key features of the vehicles were identified – e.g. drive with three-phase linear motor with winding on the vehicle and fixed rotor in the road surface, contactless dynamic vehicle powering. Attention was paid to the difference in dynamic properties compared to rail vehicles, related to the lack of the so-called ‘centering mechanism’. A development of a nominal model for the analysis of vehicle drive properties was presented. Results of simulation studies were presented for a vehicle with running-drive system construction, planned for implementation in the city of Rzeszów (Poland). While discussing the problems of building a PRT system, there was a focus on the issue of determining power and traction of the vehicle. A methodology for determining the power and traction energy consumption of the vehicle was presented for assumed conditions of travel on road segments. Input values for the calculation of power are variables describing the curvature (or bends radii) of paths of movement between stops and the course of the current speed. Output values are total traction power or traction energy (where ‘traction’ refers to the power or mechanical work of drive forces). Three basic elements of traction power were isolated: the power of kinetic energy (for acceleration/delay of vehicle movement) basic (to offset the aerodynamic force of motion resistance at constant speed) and additional losses (to offset additional motion resistance forces operating in turns at constant speed). Due to the lack of vehicle prototypes with assumed structure, it was proposed that these components are determined via simulation. The presented results relate to the calculation of demand for power and energy for the planned test section. The scope of further work was indicated: determining the required traction characteristics of electric drive, selecting the best values for supercapacitor’s capacity in the drive system, determining the technical parameters of substation.

First published online 20 October 2016

Keyword : ATN–PRT (Automated Transit Network – Personal Rapid Transit), physical model in scale; electromechanical PRT drive dynamics model, computer simulation; traction power, PRT vehicle energy demand