Source code for openmdao.test_suite.scripts.circuit_analysis

from __future__ import print_function, division, absolute_import
import unittest

import numpy as np

import openmdao.api as om
from openmdao.utils.assert_utils import assert_rel_error


[docs]class Resistor(om.ExplicitComponent): """Computes current across a resistor using Ohm's law."""
[docs] def initialize(self): self.options.declare('R', default=1., desc='Resistance in Ohms')
[docs] def setup(self): self.add_input('V_in', units='V') self.add_input('V_out', units='V') self.add_output('I', units='A') self.declare_partials('I', 'V_in', method='fd') self.declare_partials('I', 'V_out', method='fd')
[docs] def compute(self, inputs, outputs): deltaV = inputs['V_in'] - inputs['V_out'] outputs['I'] = deltaV / self.options['R']
[docs]class Diode(om.ExplicitComponent): """Computes current across a diode using the Shockley diode equation."""
[docs] def initialize(self): self.options.declare('Is', default=1e-15, desc='Saturation current in Amps') self.options.declare('Vt', default=.025875, desc='Thermal voltage in Volts')
[docs] def setup(self): self.add_input('V_in', units='V') self.add_input('V_out', units='V') self.add_output('I', units='A') self.declare_partials('I', 'V_in', method='fd') self.declare_partials('I', 'V_out', method='fd')
[docs] def compute(self, inputs, outputs): deltaV = inputs['V_in'] - inputs['V_out'] Is = self.options['Is'] Vt = self.options['Vt'] outputs['I'] = Is * (np.exp(deltaV / Vt) - 1)
[docs]class Node(om.ImplicitComponent): """Computes voltage residual across a node based on incoming and outgoing current."""
[docs] def initialize(self): self.options.declare('n_in', default=1, types=int, desc='number of connections with + assumed in') self.options.declare('n_out', default=1, types=int, desc='number of current connections + assumed out')
[docs] def setup(self): self.add_output('V', val=5., units='V') for i in range(self.options['n_in']): i_name = 'I_in:{}'.format(i) self.add_input(i_name, units='A') for i in range(self.options['n_out']): i_name = 'I_out:{}'.format(i) self.add_input(i_name, units='A') #note: we don't declare any partials wrt `V` here, # because the residual doesn't directly depend on it self.declare_partials('V', 'I*', method='fd')
[docs] def apply_nonlinear(self, inputs, outputs, residuals): residuals['V'] = 0. for i_conn in range(self.options['n_in']): residuals['V'] += inputs['I_in:{}'.format(i_conn)] for i_conn in range(self.options['n_out']): residuals['V'] -= inputs['I_out:{}'.format(i_conn)]
# note: This is defined twice in the file. Once so you can import it, and once inside a test that gets included in the docs.
[docs]class Circuit(om.Group):
[docs] def setup(self): self.add_subsystem('n1', Node(n_in=1, n_out=2), promotes_inputs=[('I_in:0', 'I_in')]) self.add_subsystem('n2', Node()) # leaving defaults self.add_subsystem('R1', Resistor(R=100.), promotes_inputs=[('V_out', 'Vg')]) self.add_subsystem('R2', Resistor(R=10000.)) self.add_subsystem('D1', Diode(), promotes_inputs=[('V_out', 'Vg')]) self.connect('n1.V', ['R1.V_in', 'R2.V_in']) self.connect('R1.I', 'n1.I_out:0') self.connect('R2.I', 'n1.I_out:1') self.connect('n2.V', ['R2.V_out', 'D1.V_in']) self.connect('R2.I', 'n2.I_in:0') self.connect('D1.I', 'n2.I_out:0') self.nonlinear_solver = om.NewtonSolver() self.nonlinear_solver.options['iprint'] = 2 self.nonlinear_solver.options['maxiter'] = 20 self.linear_solver = om.DirectSolver()
if __name__ == "__main__": import openmdao.api as om p = om.Problem() model = p.model model.add_subsystem('ground', om.IndepVarComp('V', 0., units='V')) # replacing the fixed current source with a BalanceComp to represent a fixed Voltage source # model.add_subsystem('source', IndepVarComp('I', 0.1, units='A')) model.add_subsystem('batt', om.IndepVarComp('V', 1.5, units='V')) bal = model.add_subsystem('batt_balance', om.BalanceComp()) bal.add_balance('I', units='A', eq_units='V') model.add_subsystem('circuit', Circuit()) model.add_subsystem('batt_deltaV', om.ExecComp('dV = V1 - V2', V1={'units':'V'}, V2={'units':'V'}, dV={'units':'V'})) # current into the circuit is now the output state from the batt_balance comp model.connect('batt_balance.I', 'circuit.I_in') model.connect('ground.V', ['circuit.Vg','batt_deltaV.V2']) model.connect('circuit.n1.V', 'batt_deltaV.V1') # set the lhs and rhs for the battery residual model.connect('batt.V', 'batt_balance.rhs:I') model.connect('batt_deltaV.dV', 'batt_balance.lhs:I') p.setup() ################### # Solver Setup ################### # change the circuit solver to RunOnce because we're # going to converge at the top level of the model with newton instead p.model.circuit.nonlinear_solver = om.NonlinearRunOnce() p.model.circuit.linear_solver = om.LinearRunOnce() # Put Newton at the top so it can also converge the new BalanceComp residual newton = p.model.nonlinear_solver = om.NewtonSolver() p.model.linear_solver = om.DirectSolver() newton.options['iprint'] = 2 newton.options['maxiter'] = 20 newton.options['solve_subsystems'] = True newton.linesearch = om.ArmijoGoldsteinLS() newton.linesearch.options['maxiter'] = 10 newton.linesearch.options['iprint'] = 2 # set initial guesses from the current source problem p['circuit.n1.V'] = 9.8 p['circuit.n2.V'] = .7 p.run_model()