Carlos Villanueva

Modeling and simulation of PEM fuel cell with bond graph and 20sim

Due to the increasing and highly promising use of fuel cells as an important electrical energy source, its modeling has been a major research issue for some years, trying to find mathematical models precise enough to accurately predict how a cell will behave in a real world system, without becoming too complex. Many attempts have been made using different techniques. In this paper, the authors describe a static model for the PEM (proton exchange membrane) fuel cell, developed by means of bond graphs and simulated in 20 sim. The model proves to be simple and accurate, reproducing the characteristic curve of a commercial PEM fuel cell.

A Novel Method to Estimate the Rotor Resistance of the Induction Motor Using Support Vector Machines

Modern indirect vector control based drives of the squirrel cage induction motor (SCIM) have a main weakness in the true value of the rotor time constant is always unknown, which is used by the control block to know the exact position of the rotor flux and locate the synchronous d-q axes correctly. The main parameter affecting the rotor time constant variation is the rotor resistance whose value may change because of temperature rise, flux saturation, and skin effect. A novel rotor resistance estimator of the SCIM was designed using support vector machines (SVM) as a non-linear regressor. The all drive including a SCIM model with time-varying rotor resistance was simulated. Flux errors according to the current and voltages models were obtained. SVM was trained with those flux error records and variable rotor resistance. The drive with the rotor resistance estimator in closed loop showed a well performance when was undergone to other operation conditions different to that from the training signals were obtained and nevertheless to achieve an excellent estimation of the rotor resistance, even during start up of the machine

Modeling of faults in operational amplifier circuits using bond graph

Fault detection and identification techniques based on bond graphs have proved their importance in many engineering fields. In order to apply these techniques to complex electronic and mechatronic systems, it is necessary to have bond graph models of electronic devices. In this paper a model is obtained, which reproduces the behavior of an inverter using an operational amplifier, both under normal and faulted operation conditions. The model is validated against other models currently accepted.