RLC_series example

examples/RLC_series/README.md

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+# RLC series
+
+This example simulates a [series RLC electrical circuit](https://en.wikipedia.org/wiki/RLC_circuit#Series_circuit).
+
+![An RLC series circuit](https://upload.wikimedia.org/wikipedia/commons/thumb/f/fb/RLC_series_circuit_v1.svg/500px-RLC_series_circuit_v1.svg.png)
+
+## How to run the example
+
+Just run
+```
+python main.py
+```

examples/RLC_series/RLC_series.mo

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+model RLC_series "A resistor-inductor-capacitor circuit in series with a voltage source"
+  type Current=Real(unit="A");
+  type Voltage=Real(unit="V");
+  type Capacitance=Real(unit="F");
+  type Inductance=Real(unit="H");
+  type Resistance=Real(unit="Ohm");
+  parameter Voltage V_source = 1;
+  parameter Resistance R = 1;
+  parameter Inductance L = 1;
+  parameter Capacitance C = 1;
+  Current i;
+  Voltage v_C;
+  Voltage v_L;
+  Voltage v_R;
+equation
+  V_source = v_C + v_L + v_R;
+  C*der(v_C) = i;
+  L*der(i) = v_L;
+  R*i = v_R;
+end RLC_series;

examples/RLC_series/main.py

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+from OMPython import ModelicaSystem
+from pathlib import Path
+import pandas
+import plotly.graph_objects as go
+from plotly.subplots import make_subplots
+import numpy
+
+def simulate(path_to_output_folder:Path):
+	model = ModelicaSystem(
+		str(Path(__file__).parent/'RLC_series.mo'), # Path to file where modelica code is.
+		'RLC_series', # Name of model from that file.
+	)
+
+	model.setParameters(['V_source=1','R=.4','C=1','L=1'])
+
+	path_to_results_file = path_to_output_folder/'data.csv'
+	model.setSimulationOptions(['outputFormat=csv', 'stopTime=111'])
+	model.simulate(resultfile=str(path_to_results_file))
+
+	print(f'Simulation finished, results available in {path_to_results_file}. ')
+
+	# Get the parameters used in the simulation and compute some analytical values:
+	R = float(model.getParameters()['R'])
+	L = float(model.getParameters()['L'])
+	C = float(model.getParameters()['C'])
+	omega_0 = 1/(L*C)**.5
+	alpha = R/2/L
+	print(f'R={R:.2e}, L={L:.2e}, C={C:.2e}')
+	print(f'omega_0 = {omega_0:.2e} rad/s')
+	print(f'Oscillation period = {((omega_0**2 - alpha**2)**.5/2/numpy.pi)**-1:.2e} s')
+	print(f'Decay time = {1/alpha:.2e} s')
+
+def plot(path_to_output_folder:Path):
+	data = pandas.read_csv(path_to_output_folder/'data.csv').set_index('time')
+	fig = make_subplots(
+		cols = 1,
+		rows = len(data.columns),
+		shared_xaxes = True,
+		vertical_spacing = .02,
+	)
+	for i,col in enumerate(data):
+		fig.add_trace(
+			go.Scatter(
+				x = data.index,
+				y = data[col],
+			),
+			row = i+1,
+			col = 1,
+		)
+		fig.update_yaxes(
+			title_text = col,
+			row = i+1,
+			col = 1,
+		)
+	fig.update_xaxes(title_text=data.index.name, row=i+1, col=1)
+	fig.update(layout_showlegend=False)
+	path_to_plot = path_to_output_folder/'results.html'
+	fig.write_html(path_to_plot)
+	print(f'Plots available in {path_to_plot}. ')
+
+def main():
+	# Create a directory in which to put the simulation results and plots:
+	path_to_output_folder = Path(__file__).parent/'simulation_results'
+	path_to_output_folder.mkdir(exist_ok=True)
+	# Run the simulation:
+	simulate(path_to_output_folder=path_to_output_folder)
+	# Plot the results:
+	plot(path_to_output_folder=path_to_output_folder)
+
+if __name__ == '__main__':
+	main()