This contribution proposes an identification technique of the parameters which are needed to minimise power consumption of a city-bus equipped with permanent magnet three-phase synchronous motor. A constrained optimisation problem is formulated and its solution is approximated by exploiting local flatness and physical properties of the system. The problem is posed as a two-point boundary value optimisation problem that clearly takes the structural physical constraints and the properties of the system into account. This paper verifies the efficacy of the suggested method by means of simulations of a synchronous motor used in automotive applications. Copyright © 2014 Inderscience Enterprises Ltd.