Semiconductor Modeling with Bondgraphs

Abstract

The work contained in this thesis is the conversion of a standard ``electronic circuit based'' transistor model into a ``bond graph based'' model. This bond graph model not only allows the modeler to determine the model's voltage and current trajectories, but also its power flow trajectories. While power flow can be derived from the voltage and current flows in an electrical circuit, a bond graph model uses power flow as a first principle. This first principle states that power flow is simply the rate at which energy flows between localized points in space that have different energy levels; and, energy in a closed system always remains constant. Because of these principles, a transformer can be used to allow power to flow between different types of systems such as electrical and thermal. The thesis is based on an earlier ``electronic circuit based'' transistor model proposed by Hild, who developed a Spice-like Gummel-Poon model of a bipolar junction transistor. The model was encoded in Dymola. The newly proposed bond graph model is also encoded in Dymola. It matches the earlier model perfectly in terms of its electrical properties. However, while the standard circuit simulation programs allow the modeler to specify the initial temperature of the environment, they do not adjust the temperature of the environment during the simulation. That is, these simulation programs do not modify the simulation temperature to reflect the fact that the circuit's resistors are heating up and are adding heat to the environment. The bond graph model developed in this thesis, on the other hand, lets the environment heat up.


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Last modified: May 30, 2005 -- © François Cellier