Opened 12 years ago

Closed 7 years ago

Last modified 7 years ago

#2014 closed task (fixed)

Modelica.Electrical.Spice3.Examples.CascodeCircuit

Reported by: Jens Frenkel Owned by: Volker Waurich
Priority: normal Milestone: 1.9.1
Component: Backend Version: trunk
Keywords: index reduction, remove simple equations Cc: christian.schubert@…

Description (last modified by Jens Frenkel)

The model Modelica.Electrical.Spice3.Examples.CascodeCircuit fails in simulation because the equations

4/8 (1): J1.icGD = J1.cc.cGD * der(J1.vGD)
5/9 (1): J1.icGS = J1.cc.cGS * der(J1.vGS)
13/21 (1): J2.icGD = J2.cc.cGD * der(J2.vGD)
14/22 (1): J2.icGS = J2.cc.cGS * der(J2.vGS)

are not solvable for the der(...) variables because J*.cc.cGD is zero.

If you take a look at the equation

22/30 (1): J2.vGS = v_sin.VO + (if time < v_sin.TD then 0.0 else v_sin.VA * exp((v_sin.TD - time) * v_sin.THETA) * sin(6.283185307179586 * v_sin.FREQ * (time - v_sin.TD)))

you see that the state candidate J2.vGS is the only unkown variable in the equation. Hence the variable J2.vGS is purely algebraic and the variable der(J2.vGS) is known as

der(J2.vGS) = if time < v_sin.TD then 0.0 else v_sin.VA * (exp((v_sin.TD - time) * v_sin.THETA) * 6.283185307179586 * v_sin.FREQ * cos(6.283185307179586 * v_sin.FREQ * (time - v_sin.TD)) + (-v_sin.THETA) * exp((v_sin.TD - time) * v_sin.THETA) * sin(6.283185307179586 * v_sin.FREQ * (time - v_sin.TD)))

Subsequently the variable J2.igsgmin is known from equation

15/23 (1): J2.igsgmin = 0.000000000001 * J2.vGS

Change History (6)

comment:1 by Jens Frenkel, 12 years ago

Description: modified (diff)

comment:2 by Volker Waurich, 7 years ago

Owner: changed from Jens Frenkel to Volker Waurich
Status: newassigned

the issue has been adressed by evaluation of function calls.

comment:3 by Volker Waurich, 7 years ago

Resolution: fixed
Status: assignedclosed

comment:4 by Martin Sjölund, 7 years ago

Milestone: Future

What milestone should this be closed for? (Shouldn't close with milestone=Future)

comment:5 by Volker Waurich, 7 years ago

partial function evaluation has been introduced with 1.9.1

comment:6 by Martin Sjölund, 7 years ago

Milestone: 1.9.1
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