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2010 2nd International Conference on Education Technology and Computer (ICETC)

Development of Visual Circuit Calculation Software Based on MATLAB GUI

Jingxiu Lee Department of Computer and Information Engineering

Luoyang Institute of Science Technology Luoyang, China

e-mail: [email protected]

Abstract-MA TLAB has been widely applied in circuit analysis calculation as high-powered value calculation software. Because it is inefficient to calculate by programming, and user must master MATLAB language, so the visual circuit calculation software uses object-oriented graphic technology and GUI to automatically compute and save value solution, resolution and oscillogram. Results of experiments show that this software can calculate accurately and effectively, and be easy to master, greatly improve efficiency of circuit calculation.

Keywords-MATLAB; GUIDE; Tabular matrix; Visualization; Circuit calculations

I. INTRODUCTION

Computer-aided circuit analysis has been a powerful and widely used assistant tool of circuit analysis and des.ign accompanied with the development of modem electrIcal technology and computer. MA TLAB has already bee a powerful tool in developing circuit analysis calculatIOn software, which can process scientific calculation, sign calculation and graphic process. Meanwhile it can figure out some peculiar problems which are out of the ability of Multisim[31.But now, circuit analysis calculation of MA TLAB mainly aims at particular problems, not for all. From the trends of software development, it is can be seen that friendly user interface has been basic interactive portal. The graphic user interface design tool of MA TLABGUIDE, which supports GUI, can design easily-manipulated and convenient interface with menus and controls.

II. CIRCUIT EQUATION

Circuit calculation software requires that the computer can automatically found equations and solve them in order to realize circuit auto-computation. Nowadays, there are many easily-solved circuit analysis methods applied for large complicated circuit. Table matrix can directly calculate branch voltage, branch current and node voltage without any transforms. In additional, it sees a organ as a branch, so there is no any limitation of organ types.

According to table matrix, table matrix equation is as follows: 11 0 -A-T],U

bl ,0 l

l b b l r l b J (I)

Weijuan Zhang Department of Computer and Information Engineering

Luoyang Institute of Science Technology Luoyang, China

e-mail: [email protected]

A is related matrix, Yb and Zb are matrix of describing organ features, Wb is matrix of describing electric power features, Vb' Ib and Vn respectively is branch voltage, branch current and node voltage. Sub-matrix in coefficient matrix are all square matrices. So the equation above also can be written as TX=B, whose solves is X=TIB.

III. SOFTWARE SYSTEM STRUCTURE AND FUNCTION DESIGN

Generally, circuit calculation can be included into computation of DC Steady, AC Steady and dynamic circuit. Therefore, the software package composes of DC calculation platform, AC calculation platform and dynamic circuit calculation platform.

Each model can input circuit information, display results, save results and provide help. AC circuit and dynamic circuit calculation platform also can display waveform to help user observe dynamic changes.

There are two methods of data input: one is platform input, the other is importing from Excel.

Results of DC circuit and AC circuit calculation are number, which will be saved in Excel; dynamic circuit calculation results are resolution, which will be saved in text.

The scope of waveform display can be fixed also be adjusted. AC circuit waveform is periodic sinusoidal quantity whose scope is fixed; waveform of dynamic circuit is nonperiodic whose scope can be adjusted to observe waveform widely.

IV. SOFTWARE FUNCTION IMPLEMENT

Software function implements are realized by executing callback function of controls and menu.

The foundation of circuit equation and calculation programme flowchart is illustrated as figure 1. .

Because all of three circuits founded in each calculatIOn model are different, coefficient matrix Yb, Zb are different too. For DC, Yb and Zb respectively represent conductivity and resistance of organ. Meanwhile, model founded by AC is vector model, so Yb and Zb respectively represent admittance and impedance, but for the calculation circuit model founded by dynamic circuit, Yb and Zb respectively represent calculation admittance and calculation impedance. The calculation programme and circuit equations which are coded according to flowchart in figure2, are all saved as .m file for other programme.

978-1-4244-6370-11$26.00 2010 IEEE V3-113

2010 2nd International Conference on Education Technology and Computer (ICETC)

Calculated slip branch number and independent nodes

Formation of correlation matrix

Formation ofYb, Zb, and Wb matrix based on component type

The formation tabular matrix

Figurel. Flowchart

Data import is completed by callback function of buttons, which is as follows:

[FileName PathName ]=uigetfile(C* .xls'),'Choose a File');% set up dialog box for opening file

str= [PathName FileName];% acquire path and file name shuju=xlsread(str);% read Excel into variable shuju set(handles.editl ,'string',num2str(shuju)); % set edit box

editl which displays variable shuju guidata(hObject,handles); % update hObject manually Data export is completed by callback function of menu,

whose results are saved in two ways: the number results in Excel, and the resolution in text. The callback function of Excel is as follows:

NVV=str2num(get(handles.edit7 ,'string'));% read data into variable NVV

[ FileName,PathName]=uiputfile( ... ,* .xls','Excels(* .xls ) " ...

'AC node voltage');% set up dialog box for saving file xlswriteCAC node voltage ',NVV,'range');% saved as

Excel guidata(hObject,handles ); The callback function of text is as follows: VV=get(handles.editl9,'string'), [FileN ame,PathName ]=uiputfile( ...

'* .txt','Text(* .txt)', ... 'calculation results')

fid=fopenC calculation results.txt','w'); fprintf(fid,'%s',VV), guidata(hObject,handles );

V. VISUAL INTERFACE DESIGN

GUIDE of MA TLAB provides a convenient and efficient integrate environment, where all of user controls supported by GUI are integrated together, and setup of interface appearance, attributes and behave response methods. GUIDE saves the GUI interface designed by users in FIG file. At the same time, it creates a M file which includes codes of GUI initialization and module interface layout. Therefore, friendly interface can be designed by using various controls and their functions provided by GUIDE.

VI. ApPLICATION EXAMPLE

Examplel-Calculation of AC Calculate each branch voltage, current and power. First, mark the node number, branch number; choose

branch reference direction, seen as figure2. Call-out sine steady circuit calculation platform as

figure3; input circuit information(or import data).Supposed w=lrad/s, the result as figure3 illustrated is saved in Excel. Oscillogram can be various with different variable, which can be seen in figure 4.

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2010 2nd International Conference on Education Technology and Computer (ICETC)

Example2-Calculation of Dynamic circuit Calculate circuit voltage uc(t) , supposed uc( O)=2V,

draw its waveform.

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FigureS. Dynamic circuit calculation example

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Firstly, mark circuit node and branches, seen as figure 5, then input circuit information in figure 6 shows the"dynamic circui calculation platform", choose branch voltage and input serial number 5, finally obtain voltage of branch 5 after pushing "display result" button. The resolution is:

u cCt ) = 4. 9 8 8+0. 156 0e - 6 3*e x p ( - 275 . 0*t)*(O. 1 9 15 e65*cos(315 4. *t) +O. 809 4e66*s in(315 4. *t))

After choose suitable scope of waveform, we will see the waveform of uc(t) illustrated in figure7

This sample is from reference [4],whose oscillogram is fit result of it. Reference [4] adopted PSpice to test waveform of uc(t). PSpice and Multisim only can test voltage waveform, not current waveform. However, current waveform can be obtained by choosing different variables and inputting its corresponding serial number in this simulation platform.

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