Error(s) simulating DC/DC boost converter

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Error(s) simulating DC/DC boost converter

Error(s) simulating DC/DC boost converter

Nov-01-13 19:54:38

Hi,

I am fairly new to Modelica and I am stuck on a error that I can't make sense of. I am trying to implement a very simple behavioral model of a DC/DC boost converter. It simply needs to do two things, step up the voltage while keeping Pin = Pout and regulate the output voltage to keep below a setpoint of the input current. In other words if the input current is above a certain limit the output voltage will need to drop.

I should also mention that the simulation works fine if I don't include the PID block in the converter, but then the behavior of the model is not complete.

I am sure I must be missing something so any help would be greatly appreciated!

Following are the two files I am using:

DC/DC boost converter

Code:


model DCConv7 

  extends Modelica.Electrical.Analog.Interfaces.TwoPort;

  parameter Real Pmax;

  parameter Real Vref;

  parameter Real Imax;

  Modelica.Blocks.Continuous.LimPID PID(yMax = Vref, Ti = 0.0001, Td = 0, y_start = Vref, k = 10, xi_start = Vref);

equation

  i1 = v2 * i2 / v1;

  PID.u_s = Imax;

  PID.u_m = i1;

  v2 = PID.y;

  annotation(Icon(coordinateSystem(extent = {{-100,-100},{100,100}}, preserveAspectRatio = false, initialScale = 0.1, grid = {2,2}), graphics = {Rectangle(lineColor = {255,255,255}, fillColor = {255,255,255}, fillPattern = FillPattern.Solid, extent = {{-72,-60},{-33,60}}),Line(points = {{-90,50},{-32,50}}),Line(points = {{-90,-50},{-32,-50}}),Rectangle(lineColor = {255,255,255}, fillColor = {255,255,255}, fillPattern = FillPattern.Solid, extent = {{33,-60},{72,60}}),Line(points = {{32,50},{90,50}}),Line(points = {{32,-50},{90,-50}}),Text(lineColor = {0,0,255}, extent = {{-100,10},{-80,-10}}, textString = "1"),Text(lineColor = {0,0,255}, extent = {{80,10},{100,-10}}, textString = "2"),Text(lineColor = {0,0,255}, extent = {{-146,115},{154,75}}, textString = "%name")}), Diagram(coordinateSystem(extent = {{-100,-100},{100,100}}, preserveAspectRatio = true, initialScale = 0.1, grid = {2,2}), graphics = {Text(lineColor = {0,0,255}, extent = {{0,10},{100,-10}}, textString = "2=secondary")}));

end DCConv7;

Test harness:

Code:


model TestDC

  Modelica.Electrical.Analog.Sources.ConstantVoltage constantvoltage1(V = 10);

  Modelica.Electrical.Analog.Basic.Resistor resistor1(R = 2000);

  Modelica.Electrical.Analog.Basic.Ground ground1;

  Modelica.Electrical.Analog.Basic.Capacitor capacitor1(C = 0.001, v(start = 100));

  /*DCConv1 dcdc(Pout = 80, Vout = 100, Vinmin = 1, Vinmax = 50, eff = 1);*/

  DCConv7 dcdc(Pmax = 80, Vref = 100, Imax = 2000);

  Modelica.Blocks.Sources.Pulse pulse(startTime = 0.5, amplitude = 1, period = 0.01, width = 50);

  Modelica.Electrical.Analog.Ideal.ControlledIdealClosingSwitch switch;

  Modelica.Electrical.Analog.Sources.SignalVoltage swDrv;

  Modelica.Electrical.Analog.Sensors.PowerSensor Pin;

  /*Modelica.Electrical.Analog.Sensors.PowerSensor Pout;*/

equation

  connect(capacitor1.n,ground1.p);

  connect(resistor1.n,ground1.p);

  connect(constantvoltage1.n,ground1.p);

  connect(constantvoltage1.p,Pin.pc);

  connect(constantvoltage1.p,Pin.pv);

  connect(Pin.nv,ground1.p);

  connect(dcdc.p1,Pin.nc);

  connect(dcdc.n1,ground1.p);

  connect(dcdc.p2,capacitor1.p);

  connect(dcdc.n2,ground1.p);

  connect(dcdc.p2,switch.p);

  connect(switch.n,resistor1.p);

  connect(switch.control,swDrv.p);

  connect(swDrv.n,ground1.p);

  connect(swDrv.v,pulse.y);

  annotation(Icon(coordinateSystem(extent = {{-100,-100},{100,100}}, preserveAspectRatio = true, initialScale = 0.1, grid = {2,2})), Diagram(coordinateSystem(extent = {{-100,-100},{100,100}}, preserveAspectRatio = true, initialScale = 0.1, grid = {2,2})), experiment(StartTime = 0, StopTime = 1, Tolerance = 0.000001));

end TestDC;

Using the default simulation parameters I am getting the following error:

Code:


LOG_NLS           | warning | Error solving nonlinear system Nonlinear function (residualFunc59, size 1) at time 0.002

LOG_NLS           | warning | Error solving nonlinear system Nonlinear function (residualFunc59, size 1) at time 0.002

stdout            | info    | model terminate | non-linear system solver failed. | Simulation terminated at time 0.002

LOG_STATS         | info    | ### STATISTICS ###

LOG_STATS         | info    | timer

|                 | |       | |   0.00136495s [  0.2%] pre-initialization

|                 | |       | |   0.00048028s [  0.1%] initialization

|                 | |       | |     0.552368s [ 99.1%] steps

|                 | |       | |   0.00139648s [  0.3%] creating output-file

|                 | |       | | 1.83313e-006s [  0.0%] event-handling

|                 | |       | | 1.02655e-005s [  0.0%] overhead

|                 | |       | |   0.00176347s [  0.3%] simulation

|                 | |       | |     0.557385s [100.0%] total

LOG_STATS         | info    | events

|                 | |       | |     0 state events

|                 | |       | |     0 time events

LOG_STATS         | info    | solver

|                 | |       | |   113 steps taken

|                 | |       | |   139 calls of functionODE

|                 | |       | |    23 evaluations of jacobian

|                 | |       | |     3 error test failures

|                 | |       | |     0 convergence test failures

LOG_STATS         | info    | ### END STATISTICS ###

Process crashed

Simulation process exited with code -2

If I modify equation i1 = -v2 * i2 / v1 to i1 = v2 * i2 / (v1+0.000001)

Code:


 DASSL--  AT T (=R1) AND STEPSIZE H (=R2) THE

      In above,  R1 =   .2456570990108E-03   R2 =   .6624589961672E-18

 DASSL--  CORRECTOR FAILED TO CONVERGE REPEATEDLY

 DASSL--  OR WITH ABS(H)=HMIN

stdout            | warning | The corrector could not converge.

stdout            | warning | can't continue. time = 0.000246

stdout            | info    | model terminate | Integrator failed. | Simulation terminated at time 0.000245657

LOG_STATS         | info    | ### STATISTICS ###

LOG_STATS         | info    | timer

|                 | |       | |   0.00144011s [ 13.5%] pre-initialization

|                 | |       | |   0.00056717s [  5.3%] initialization

|                 | |       | |    0.0056684s [ 53.0%] steps

|                 | |       | |   0.00142397s [ 13.3%] creating output-file

|                 | |       | | 1.09988e-006s [  0.0%] event-handling

|                 | |       | | 7.69914e-006s [  0.1%] overhead

|                 | |       | |   0.00157869s [ 14.8%] simulation

|                 | |       | |    0.0106871s [100.0%] total

LOG_STATS         | info    | events

|                 | |       | |     0 state events

|                 | |       | |     0 time events

LOG_STATS         | info    | solver

|                 | |       | |     0 steps taken

|                 | |       | |     0 calls of functionODE

|                 | |       | |     0 evaluations of jacobian

|                 | |       | |     0 error test failures

|                 | |       | |     0 convergence test failures

LOG_STATS         | info    | ### END STATISTICS ###

Process crashed

Simulation process exited with code -8