Abstract:

The present study is the further development of the work presented in Edulearn 2016 "A MATLAB toolbox for symbolic electrical circuit analysis". In that study the authors proposed a toolbox, within the MATLAB work environment, that allows to analyze electrical circuits symbolically, both in the Laplace domain and the time domain.

In this extension of the study, some specific parts of the computational core have been modified to adapt it to the new demands of the latest versions of MATLAB (especially regarding the elimination of "string" as a way of defining symbolic variables). The scope of the application of the tool developed is Industrial Engineering bachelor degree, in the specialities of Electricity and Electronics.

Specifically, it is focused on the field of an electrical circuit resolution symbolically. The idea is still that of the original article, but specific utilities are being developed to provide new functionalities with no need from the user to code them. The way to approach the analytical resolution of the circuits, continues being from "basic branches", in the Laplace domain and, if any, to pass to the time domain, through the Laplace Reverse Transform (ILT).

The circuits may contain parameters, which will not be assigned a previous value, but it could be done after if there is interest. This brings an unusual power to the toolbox, although it can not always be exploited since, if the number of parameters is greater than three (simultaneously), some results may be obtained in the Laplace domain, but it will be almost impossible to be able to get exact results in the time domain (due to the impossibility of obtaining the associated ILT), as would happen if the circuit is solved by hand.

The method of use has been modified, so that the system analyzes only in the Laplace domain and, if requested, passes the results obtained (and manipulated from MATLAB) to the time domain. It is necessary create small files "scripts" that describe the circuit (several if, for example, they are intended to make commutations in it), which it will be named in a format accepted by MATLAB: "file.m". Although it is possible to operate with .m files directly from the console of MATLAB, it is highly recommended to generate previously some new "live script" files (with extension ".mlx") in order to obtain complete reports of the respective simulations and improve the usability for the user.

For the moment, some new MATLAB scripts have already been developed, which allow to analyze a wide range of simulations of circuits, in a relatively easy way. Now the authors are completing the modifications to the system to get Thevenin equivalent circuits and resolving circuits in Sine-steady Stationary Regime (RES). Also the authors plan to address the study of harmonics, quadrupoles, frequency response, symmetric components, etc.

Keywords:

Electrical Circuit, MATLAB, Symbolic, Innovation, Educational Software.