modelDSreal

Electrical real diode of the Modelica bond graph library

Extends from Interfaces.TwoPort (Partial model invoking two bondgraphic connectors).

Information

The real diode source element is a directed TwoPort element. It inherits the effort and flow variables from the directed TwoPort. Real diodes are a special class of non-linear resistors.

The real diode model consists of the diode itself and an parallel Ohmic resistance R. The diode formula essentially is:

f = Ids*(exp(e/Vt) - 1)

However, if the exponent e/Vt reaches the limit Maxexp, the diode characterisic is linearly continued to avoid overflow.

The diode source element is a bit more complex than the diode element, because it not only computes the heat flow, but also the temperature dependence of the diode characteristic.

The resistive source element has free causality on the primary side, and fixed causality on the secondary side. The causality stroke is at the element on the secondary side (a source of entropy, rather than a source of temperature).


Potential variables:

 e1:      Bondgraphic effort variable of inflow

 f1:      Bondgraphic flow variable of inflow, normalized positive for flows into the model

 e2:      Bondgraphic effort variable of outflow

 f2:      Bondgraphic flow variable of outflow, normalized positive for flows out of the model

 Vt:      Thermal voltage


Parameters:

 Ids:     Saturation current (default value = 1e-6 Amp)

 Maxexp:  Maximum exponent (default value = 15)

 R:       Parallel Ohmic leakage resistance (default value = 1e8 Ohm)

 EG:      Activation energy (default value = 1.11 J)

 N:       Emission coefficient (default value = 1)

 TNOM:    Nominal temperature (default value = 300.15 K)

 XTI:     Temperature exponent of saturation current (default value = 3)


Equations:

Vt = k*e2/q
dchar = exlin((v/(N*Vt)), Maxexp) - 1
tdep = exp((e2/TNOM - 1)*EG/(N*Vt))*pow(e2/TNOM, XTI/N)
f1 = Ids*tdep*dchar + e1/R
f2 = (e1/e2)*f1

Parameters

TypeNameDefaultDescription
Modelica.SIunits.EntropykModelica.Constants.kBoltzmann's constant
Modelica.SIunits.ElectricChargeq1.6021892e-19Electron charge
Modelica.SIunits.CurrentIds1.e-6Saturation current
Modelica.SIunits.VoltageEG1.11Energy gap of Si at 300 K
RealN1Emission coefficient
Modelica.SIunits.TemperatureTNOM300.15Nominal temperature
RealXTI3Temperature exponent of saturation current
RealMaxexp15Max. exponent for linear continuation
Modelica.SIunits.ResistanceR1.e8Parallel Ohmic resistance

Connectors

TypeNameDefaultDescription
BondLib.Interfaces.BondConBondCon1 (from TwoPort)Left bond graph connector
BondLib.Interfaces.BondConBondCon2 (from TwoPort)Right bond graph connector

Components

TypeNameDefaultDescription
Reale1 (from TwoPort)Bondgraphic primary effort
Realf1 (from TwoPort)Bondgraphic primary flow
Reale2 (from TwoPort)Bondgraphic secondary effort
Realf2 (from TwoPort)Bondgraphic secondary flow
Modelica.SIunits.VoltageVtThermal voltage

Contents

NameDescription
exlinprotectedExponential function linearly continued for x > Maxexp
powprotectedJust a helper function for x^y