Partial Classes Describe Common Properties

1 Types from Modelica.SIunits

type Voltage = Real(unit = "V");
type Current = Real(unit = "A");

2 Electrical Connectors

connector Pin Voltage v; flow Current i; end Pin;

3 Components

3.1 TwoPin

The class prefix partial is used to indicate that a class is incomplete such that it cannot be instatiated. The class TwoPin can be used to define our own Resistor, Capacitor, Inductor, Voltage source AC and Ground classes.

partial class TwoPin "Superclass of elements with two electrical pins" Pin p, n; Voltage v; Current i; equation v = p.v - n.v; p.i + n.i = 0; i = p.i; end TwoPin;

3.2 Resistor

class Resistor "Ideal electrical Resistor" extends TwoPin; parameter Real R(unit = "Ohm") "Resistance"; equation R*i = v; end Resistor;

3.3 Capacitor

class Capacitor "Ideal electrical Capacitor" extends TwoPin; parameter Real C(unit = "F") "Capacitance"; equation C*der(v) = i; end Capacitor;

3.4 Inductor

class Inductor "Ideal electrical Inductor" extends TwoPin; parameter Real L(unit = "H") "Inductance"; equation v = L*der(i); end Inductor;

3.5 VsourceAC

class VsourceAC "Sin-wave voltage source" extends TwoPin; parameter Voltage VA = 220 "Amplitude"; parameter Real f(unit = "Hz") = 50 "Frequency"; constant Real PI = 3.141592653589793; input Voltage u; equation v = u; u = VA*sin(2*PI*f*time); end VsourceAC;

3.6 Ground

class Ground Pin p; equation p.v = 0; end Ground;

4 SimpleCircuit

Based on these classes we can declare the Simple Circuit Model:

class SimpleCircuit Resistor R1(R = 10); Capacitor C(C = 0.01, v(fixed = true)); Resistor R2(R = 100); Inductor L(L = 0.1, i(fixed = true)); VsourceAC AC(f = 1); Ground G; equation connect(AC.p, R1.p); // 1, Capacitor circuit connect(R1.n, C.p); // Wire 2 connect(C.n, AC.n); // Wire 3 connect(R1.p, R2.p); // 2, Inductor circuit connect(R2.n, L.p); // Wire 5 connect(L.n, C.n); // Wire 6 connect(AC.n, G.p); // 7, Ground end SimpleCircuit;

5 SimpleCircuit Simulation

simulate( SimpleCircuit )
plot( {R1.v, R2.v } )

plot( {R1.i,R2.i} )