Ph.D. Thesis title:

Efficiency Improvement in Autonomous Electric Vehicles using Dynamic Commutation of Energy Resources.

Author:

Julio Garcia Calvete

Director:

Rafael Pindado / Ricard Bosch

Reading Date:

21/05/2010

Abstract:

The need of having autonomous traction systems, together with the increasing availability limitation and rise of cost of the fossil fuels, force the check-up of the systems of traction, driving conceptual improvements in the electric vehicles (EV), giving advantageous systems over the present ones.

This thesis “Efficiency Improvement in Autonomous Electric Vehicles using Dynamic Commutation of Energy Resources” studies, proposes and it carries out its main multidisciplinary contributions in the areas of electric and electronic engineering.

This thesis proposes a vision of electric traction stand-alone systems, as systems of energetic management, using intelligent way available resources and assigning them again dynamically in a controlled way, through techniques of commutation.

The proposed topic is dealt with to three levels: A first level that consists of a dynamic method of energetic management of resources. A second level where the method is applied to a generic model of EV, and finally, a prototype where the proposed model is verified through two matrixes' management of batteries (in all 17 batteries), a bidirectional inverter and a three-phase asynchronous motor of 1,5 CV.

Within the evolution of EV the three-phase power converters are dealt bidirectional multilevel, operating with voltage of bus symmetrical and variable. This thesis also studies the bridges feeding, dealing with stand-alone systems and, therefore, not connected to the utility grid, considering especially the energy flows and the energy recovery in the braking process, using the electrical engine as a generator.

Depending on the different energetic formats that appear, must be convenient the energetic accumulator used as secondary (SESU) constituted by Flywheel or Ultracapacitors. The communications need is also studied, in such a way that they enable the control of the system and the global management of the energy in the same one.

As a result of this work, two patents have been requested. The patent P200902012 entitled “Método y dispositivo de conmutación de recursos energéticos para sistemas eléctricos autónomos” (Method of energy resources commutation system for autonomous electrical systems), describes the applicability and operation of system arrays for energy storage. This patent refers to a set of energy accumulators able to commute his connections to provide an energy management system and improvement its performance.

This method includes the commutation of elements (batteries, ultracapacitors, flywheels, etc.) with changing configurations among serial, parallel and mixed, with the aim of improve the energy availability. The patent P200902013 entitled “Servomando para el control de vehículos” (servocontrol for control of vehicles) describes a device designed and built to control the system during laboratory tests. This device is an electromechanical human interface used as system control and data monitoring display.


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