Chapter 1
Introduction
In 1993 at the Technische Universit¨at M¨unchen (TUM), began the project ”Sonderforschung-bereich 365” (SFB 365), an environmentally-friendly propulsion technology for a power train. Industrial partners such as ZF F riedrichshaf enAG, OpelP owertrainGmbH, ZF − SACHSAG and EP COSAG joined this research. The definition of the Hybrid Electric Vehicle is given by Technical Committee 69 (Electric Road Vehicles) of the International Electrotechnical Energy Commission - is a vehicle in which propulsion energy is available from two or more kinds or types of energy stores, sources, or converters and at least one of them can deliver electrical [5]- The goals of SFB 365 are:
• fuel economy
• reduction of pollution emissions
Figure 1.1 shows the hybrid concept. The propulsion can be due to an internal combustion engine (ICE) or to a separate Electric motor, and a special infinitely variable mechanical transmission (IVT) is included. This is in order that both motors can work with opti-mal points of torque and speed based on the minimum fuel consumption. The controller coordinates the work of the ICE, IVT and the electric motor.
1.1
Objective of the Thesis
Figure 1.2 shows the energy flow between the components of the car, emphasizing the elec-tric powertrain system. The elecelec-tric system is composed of a battery, a bidirectional AC-DC inverter, a DC-DC converter, supercaps and a synchronous motor. The objective of this thesis is to calculate the efficiency of the DC-DC converter at different points of operation. This is in order to draw efficiency maps that will be compared with the efficiency maps of
Figure 1.1: concept of a hybrid car ICE IVT Inverter DC-DC Converter Battery Ultracaps Wheels Electric Motor/Generator
Figure 1.2: Energy flow in a hybrid car
the other components, to find the most economical points of operation of the global system. A further challenge of the dissertation has been the investigation of the Three-Phase con-verter, in particular the evaluation of the current ripple across the inductor, and the voltage capacitor ripple.
