Wrong results in the CharacteristicIdealDiode example

[casella]

The comparison of the results of the MTK model obtained from the Base Modelica model Modelica.Electrical.Analog.Examples.CharacteristicIdealDiodes.bmo do not match the reference results, see report.

This is the diagram of the circuit

Diode With_Ron_Goff has an internal resistance Ron = 0.1 Ohm, while the series-connected resistor R2 has much smaller internal resistance of 0.001 Ohm. Hence, between time = 0.2 and time = 0.3, when the diode is conducting, 99% of the sinusoidal source voltage drops on the diode, so that With_Ron_Goff.v is almost a sinusoidal signal, as shown by the reference result in blue.

The Julia MTK model result in red is badly off in that interval. This should be investigated.

[casella]

Here is the .bmo code of an MWE which only contains the With_Ron_Goff diode and R2 resistor:

//! base 0.1.0
package 'MWE'
  model 'MWE' "Characteristic of ideal diodes"
    Real 'With_Ron_Goff.v'(unit = "V", quantity = "ElectricPotential") "Voltage drop of the two pins (= p.v - n.v)";
    Real 'With_Ron_Goff.p.v'(unit = "V", quantity = "ElectricPotential") "Potential at the pin";
    Real 'With_Ron_Goff.p.i'(unit = "A", quantity = "ElectricCurrent") "Current flowing into the pin";
    Real 'With_Ron_Goff.n.v'(unit = "V", quantity = "ElectricPotential") "Potential at the pin";
    Real 'With_Ron_Goff.n.i'(unit = "A", quantity = "ElectricCurrent") "Current flowing into the pin";
    Real 'With_Ron_Goff.i'(unit = "A", quantity = "ElectricCurrent") "Current flowing from pin p to pin n";
    parameter Real 'With_Ron_Goff.Ron'(min = 0.0, unit = "Ohm", quantity = "Resistance") = 0.1 "Forward state-on differential resistance (closed resistance)";
    parameter Real 'With_Ron_Goff.Goff'(min = 0.0, unit = "S", quantity = "Conductance") = 0.1 "Backward state-off conductance (opened conductance)";
    parameter Real 'With_Ron_Goff.Vknee'(min = 0.0, unit = "V", quantity = "ElectricPotential") = 0.0 "Forward threshold voltage";
    parameter Boolean 'With_Ron_Goff.useHeatPort' = false "= true, if heatPort is enabled" annotation(Evaluate = true);
    parameter Real 'With_Ron_Goff.T'(nominal = 300.0, start = 288.15, min = 0.0, displayUnit = "degC", unit = "K", quantity = "ThermodynamicTemperature") = 293.15 "Fixed device temperature if useHeatPort = false";
    Real 'With_Ron_Goff.LossPower'(unit = "W", quantity = "Power") "Loss power leaving component via heatPort";
    Real 'With_Ron_Goff.T_heatPort'(nominal = 300.0, start = 288.15, min = 0.0, displayUnit = "degC", unit = "K", quantity = "ThermodynamicTemperature") "Temperature of heatPort";
    Boolean 'With_Ron_Goff.off'(start = true) "Switching state";
    Real 'With_Ron_Goff.s'(start = 0.0, unit = "1") "Auxiliary variable for actual position on the ideal diode characteristic";
    constant Real 'With_Ron_Goff.unitVoltage'(unit = "V", quantity = "ElectricPotential") = 1.0;
    constant Real 'With_Ron_Goff.unitCurrent'(unit = "A", quantity = "ElectricCurrent") = 1.0;
    parameter Real 'SineVoltage1.V'(start = 1.0, unit = "V", quantity = "ElectricPotential") = 10.0 "Amplitude of sine wave";
    parameter Real 'SineVoltage1.phase'(displayUnit = "deg", unit = "rad", quantity = "Angle") = 0.0 "Phase of sine wave";
    parameter Real 'SineVoltage1.f'(start = 1.0, unit = "Hz", quantity = "Frequency") = 1.0 "Frequency of sine wave";
    Real 'SineVoltage1.v'(unit = "V", quantity = "ElectricPotential") "Voltage drop of the two pins (= p.v - n.v)";
    Real 'SineVoltage1.p.v'(unit = "V", quantity = "ElectricPotential") "Potential at the pin";
    Real 'SineVoltage1.p.i'(unit = "A", quantity = "ElectricCurrent") "Current flowing into the pin";
    Real 'SineVoltage1.n.v'(unit = "V", quantity = "ElectricPotential") "Potential at the pin";
    Real 'SineVoltage1.n.i'(unit = "A", quantity = "ElectricCurrent") "Current flowing into the pin";
    Real 'SineVoltage1.i'(unit = "A", quantity = "ElectricCurrent") "Current flowing from pin p to pin n";
    parameter Real 'SineVoltage1.signalSource.amplitude' = 10.0 "Amplitude of sine wave";
    parameter Real 'SineVoltage1.signalSource.f'(start = 1.0, unit = "Hz", quantity = "Frequency") = 1.0 "Frequency of sine wave";
    parameter Real 'SineVoltage1.signalSource.phase'(displayUnit = "deg", unit = "rad", quantity = "Angle") = 0.0 "Phase of sine wave";
    parameter Boolean 'SineVoltage1.signalSource.continuous' = false "Make output continuous by starting at offset + amplitude*sin(phase)" annotation(Evaluate = true);
    Real 'SineVoltage1.signalSource.y' "Connector of Real output signal";
    parameter Real 'SineVoltage1.signalSource.offset' = -9.0 "Offset of output signal y";
    parameter Real 'SineVoltage1.signalSource.startTime'(unit = "s", quantity = "Time") = 0.0 "Output y = offset for time < startTime";
    parameter Real 'SineVoltage1.offset'(unit = "V", quantity = "ElectricPotential") = -9.0 "Voltage offset";
    parameter Real 'SineVoltage1.startTime'(unit = "s", quantity = "Time") = 0.0 "Time offset";
    Real 'Ground1.p.v'(unit = "V", quantity = "ElectricPotential") "Potential at the pin";
    Real 'Ground1.p.i'(unit = "A", quantity = "ElectricCurrent") "Current flowing into the pin";
    parameter Real 'R2.R'(start = 1.0, unit = "Ohm", quantity = "Resistance") = 0.001 "Resistance at temperature T_ref";
    parameter Real 'R2.T_ref'(nominal = 300.0, start = 288.15, min = 0.0, displayUnit = "degC", unit = "K", quantity = "ThermodynamicTemperature") = 300.15 "Reference temperature";
    parameter Real 'R2.alpha'(unit = "1/K", quantity = "LinearTemperatureCoefficient") = 0.0 "Temperature coefficient of resistance (R_actual = R*(1 + alpha*(T_heatPort - T_ref))";
    Real 'R2.v'(unit = "V", quantity = "ElectricPotential") "Voltage drop of the two pins (= p.v - n.v)";
    Real 'R2.p.v'(unit = "V", quantity = "ElectricPotential") "Potential at the pin";
    Real 'R2.p.i'(unit = "A", quantity = "ElectricCurrent") "Current flowing into the pin";
    Real 'R2.n.v'(unit = "V", quantity = "ElectricPotential") "Potential at the pin";
    Real 'R2.n.i'(unit = "A", quantity = "ElectricCurrent") "Current flowing into the pin";
    Real 'R2.i'(unit = "A", quantity = "ElectricCurrent") "Current flowing from pin p to pin n";
    parameter Boolean 'R2.useHeatPort' = false "= true, if heatPort is enabled" annotation(Evaluate = true);
    parameter Real 'R2.T'(nominal = 300.0, start = 288.15, min = 0.0, displayUnit = "degC", unit = "K", quantity = "ThermodynamicTemperature") = 300.15 "Fixed device temperature if useHeatPort = false";
    Real 'R2.LossPower'(unit = "W", quantity = "Power") "Loss power leaving component via heatPort";
    Real 'R2.T_heatPort'(nominal = 300.0, start = 288.15, min = 0.0, displayUnit = "degC", unit = "K", quantity = "ThermodynamicTemperature") "Temperature of heatPort";
    Real 'R2.R_actual'(unit = "Ohm", quantity = "Resistance") "Actual resistance = R*(1 + alpha*(T_heatPort - T_ref))";
  equation
    'R2.n.v' = 'Ground1.p.v';
    'R2.n.v' = 'SineVoltage1.n.v';
    'With_Ron_Goff.n.v' = 'R2.p.v';
    'SineVoltage1.p.v' = 'With_Ron_Goff.p.v';
    'R2.p.i' + 'With_Ron_Goff.n.i' = 0.0;
    'SineVoltage1.p.i' + 'With_Ron_Goff.p.i' = 0.0;
    'R2.n.i' + 'Ground1.p.i' + 'SineVoltage1.n.i' = 0.0;
    'With_Ron_Goff.off' = 'With_Ron_Goff.s' < 0.0;
    'With_Ron_Goff.v' = 'With_Ron_Goff.s' * (if 'With_Ron_Goff.off' then 1.0 else 0.1);
    'With_Ron_Goff.i' = 'With_Ron_Goff.s' * (if 'With_Ron_Goff.off' then 0.1 else 1.0);
    'With_Ron_Goff.LossPower' = 'With_Ron_Goff.v' * 'With_Ron_Goff.i';
    'With_Ron_Goff.T_heatPort' = 293.15;
    0.0 = 'With_Ron_Goff.p.i' + 'With_Ron_Goff.n.i';
    'With_Ron_Goff.i' = 'With_Ron_Goff.p.i';
    'With_Ron_Goff.v' = 'With_Ron_Goff.p.v' - 'With_Ron_Goff.n.v';
    'SineVoltage1.signalSource.y' = (if time < 0.0 then 0.0 else 10.0 * 'Modelica.Math.sin'(6.283185307179586 * time)) - 9.0;
    'SineVoltage1.v' = 'SineVoltage1.signalSource.y';
    0.0 = 'SineVoltage1.p.i' + 'SineVoltage1.n.i';
    'SineVoltage1.i' = 'SineVoltage1.p.i';
    'SineVoltage1.v' = 'SineVoltage1.p.v' - 'SineVoltage1.n.v';
    'Ground1.p.v' = 0.0;
    'R2.R_actual' = 0.001;
    'R2.v' = 'R2.R_actual' * 'R2.i';
    'R2.LossPower' = 'R2.v' * 'R2.i';
    'R2.T_heatPort' = 300.15;
    0.0 = 'R2.p.i' + 'R2.n.i';
    'R2.i' = 'R2.p.i';
    'R2.v' = 'R2.p.v' - 'R2.n.v';
    annotation(experiment(StopTime = 1));
  end 'MWE';
end 'MWE';

[AayushSabharwal]

Automatic discontinuity detection in MTK is still a WIP. Handling this requires adding a callback which steps to the discontinuity (With_Ron_Goff.s ~ 0) and updates the condition With_Ron_Godd.off appropriately.

[jClugstor]

#104 should fix this hopefully, it adds the necessary callbacks.

[casella]

Let's see the results of the CI tomorrow.

[casella]

Unfortunately #104 didn't pass the CI tests.

[casella]

Now #104 is merged in, but the results are still not OK, see verification report.