EXAMPLE: busbar joule heating

examples/low_frequency/magnetic/joule_heating.py

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+# # Busbar Joule Heating Analysis
+#
+# This example demonstrates how to set up and solve a busbar Joule heating analysis using PyAEDT.
+# The analysis captures frequency-dependent phenomena including skin effect, current redistribution,
+# and AC losses in power electronics systems.
+#
+# 1. Import packages and instantiate the application.
+# 2. Create busbar geometry with input/output terminals and assign materials.
+# 3. Set up current excitations following Kirchhoff's laws and configure analysis.
+# 4. Run eddy current analysis and extract engineering results.
+#
+# Keywords: **Busbar**, **Joule heating**, **Eddy current**, **Skin effect**
+
+# ## Prerequisites
+#
+# ### Perform imports
+
+# +
+import math
+import os
+import tempfile
+import time
+
+import ansys.aedt.core  # Interface to Ansys Electronics Desktop
+
+# -
+
+# ### Define constants
+# Constants help ensure consistency and avoid repetition throughout the example.
+
+AEDT_VERSION = os.getenv("AEDT_VERSION", "2025.2")
+NUM_CORES = 4
+# Run headless in CI environments to avoid UI launch failures
+NG_MODE = True
+
+# Geometry parameters (mm)
+BUSBAR_L = 100.0
+BUSBAR_W = 10.0
+BUSBAR_H = 5.0
+TAB_L = 5.0
+TAB_W = 3.0
+TAB_H = 3.0
+
+# Electrical parameters
+I1 = 100.0  # Input current 1 (A)
+I2 = 100.0  # Input current 2 (A)
+FREQ = 50  # Frequency (Hz)
+
+# Gate solver execution for CI/doc builds
+RUN_SOLVER = os.getenv("PYAEDT_RUN_SOLVER", "0") == "1"
+
+# ### Create temporary directory
+#
+# Create a temporary working directory.
+# The name of the working folder is stored in ``temp_folder.name``.
+#
+# > **Note:** The final cell in the notebook cleans up the temporary folder. If you want to
+# > retrieve the AEDT project and data, do so before executing the final cell in the notebook.
+
+temp_folder = tempfile.TemporaryDirectory(suffix=".ansys")
+
+# ### Launch application
+#
+# Launch Maxwell 3D for eddy current analysis of the busbar system.
+
+project_name = os.path.join(temp_folder.name, "busbar_joule_heating.aedt")
+m3d = ansys.aedt.core.Maxwell3d(
+    project=project_name,
+    design="BusbarJouleHeating",
+    solution_type="Eddy Current",
+    version=AEDT_VERSION,
+    non_graphical=NG_MODE,
+    new_desktop=True,
+)
+m3d.modeler.model_units = "mm"
+
+# ## Model Preparation
+#
+# Create the busbar geometry, assign materials and boundary conditions,
+# and configure the electromagnetic analysis setup.
+
+# ### Create 3D model
+#
+# Build the busbar geometry including main conductor and terminal tabs.
+# Main busbar
+busbar = m3d.modeler.create_box(origin=[0, 0, 0], sizes=[BUSBAR_L, BUSBAR_W, BUSBAR_H], name="MainBusbar")
+m3d.assign_material(busbar, "copper")
+
+# Input tabs
+input_tab1 = m3d.modeler.create_box(origin=[-TAB_L, 1.0, 0.0], sizes=[TAB_L, TAB_W, BUSBAR_H], name="InputTab1")
+m3d.assign_material(input_tab1, "copper")
+
+input_tab2 = m3d.modeler.create_box(origin=[-TAB_L, 6.0, 0.0], sizes=[TAB_L, TAB_W, BUSBAR_H], name="InputTab2")
+m3d.assign_material(input_tab2, "copper")
+
+# Output tab
+output_tab = m3d.modeler.create_box(origin=[BUSBAR_L, 3.0, 0.0], sizes=[TAB_L, 4.0, BUSBAR_H], name="OutputTab")
+m3d.assign_material(output_tab, "copper")
+
+# Unite all parts
+united = m3d.modeler.unite([busbar, input_tab1, input_tab2, output_tab])
+conductor = m3d.modeler[united] if isinstance(united, str) else united
+conductor.name = "CompleteBusbar"
+
+# ### Assign boundary conditions
+#
+# Set up current excitations on terminal faces following Kirchhoff's current law.
+
+# Sort faces by x-coordinate to identify input and output terminals
+faces_sorted = sorted(conductor.faces, key=lambda f: f.center[0])
+left_x = faces_sorted[0].center[0]
+right_x = faces_sorted[-1].center[0]
+
+# Get faces at left and right ends
+left_faces = [f for f in faces_sorted if abs(f.center[0] - left_x) < 1e-3]
+right_faces = [f for f in faces_sorted if abs(f.center[0] - right_x) < 1e-3]
+
+# Select terminal faces
+input_face1 = left_faces[0].id
+input_face2 = left_faces[1].id if len(left_faces) > 1 else left_faces[0].id
+output_face = right_faces[0].id
+
+
+# Assign current excitations (following Kirchhoff's current law)
+current1 = m3d.assign_current(assignment=input_face1, amplitude=I1, phase=0, name="InputCurrent1")
+
+current2 = m3d.assign_current(assignment=input_face2, amplitude=I2, phase=0, name="InputCurrent2")
+
+current3 = m3d.assign_current(assignment=output_face, amplitude=-(I1 + I2), phase=0, name="OutputCurrent")
+
+# Create air region for boundary conditions
+air = m3d.modeler.create_air_region(x_pos=0, y_pos=50, z_pos=100, x_neg=0, y_neg=50, z_neg=100)
+
+# ### Define solution setup
+#
+# Configure eddy current analysis with frequency and convergence settings.
+
+setup = m3d.create_setup("EddyCurrentSetup")
+setup.props["Frequency"] = f"{FREQ}Hz"
+setup.props["PercentError"] = 2
+# Reduce maximum passes for CI to shorten solve time
+setup.props["MaximumPasses"] = 4
+setup.props["MinimumPasses"] = 1
+setup.props["PercentRefinement"] = 20
+
+# Assign mesh for skin effect resolution
+mesh = m3d.mesh.assign_length_mesh(
+    assignment=conductor.name,
+    maximum_length=3.0,  # 3mm elements for skin effect resolution
+    name="ConductorMesh",
+)
+
+# ### Run analysis
+#
+# Execute the eddy current solver.
+
+validation = m3d.validate_simple()
+if RUN_SOLVER:
+    m3d.analyze_setup(setup.name)
+else:
+    print("Solver run skipped (set PYAEDT_RUN_SOLVER=1 to enable).")
+
+# ## Postprocess
+#
+# Extract and visualize the electromagnetic field results and calculate
+# engineering metrics for the busbar Joule heating analysis.
+
+# ### Evaluate loss
+#
+# Extract Ohmic loss (Joule heating) from the field solution.
+
+if RUN_SOLVER:
+    setup_sweep = f"{setup.name} : LastAdaptive"
+    solution_data = m3d.post.get_solution_data(
+        expressions=["SolidLoss"],
+        report_category="EddyCurrent",
+        setup_sweep_name=setup_sweep,
+    )
+    total_loss = solution_data.data_magnitude()[0]
+else:
+    total_loss = 0.0
+
+# ### Visualize fields
+#
+# Create field plots to visualize current density, electric field, and power loss distributions.
+
+if RUN_SOLVER:
+    j_plot = m3d.post.create_fieldplot_surface(assignment=conductor.name, quantity="Mag_J", plot_name="Current_Density_Magnitude")
+
+    e_plot = m3d.post.create_fieldplot_surface(assignment=conductor.name, quantity="Mag_E", plot_name="Electric_Field_Magnitude")
+
+    joule_plot = m3d.post.create_fieldplot_volume(
+        assignment=conductor.name,
+        quantity="Ohmic_Loss",
+        plot_name="Joule_Heating_Distribution",
+    )
+else:
+    print("Field plots skipped (no solver run).")
+
+# ### Calculate engineering metrics
+#
+# Compute key electrical parameters including resistance, loss density, and skin depth.
+print("\nANALYSIS RESULTS")
+
+# Basic electrical parameters
+total_current = I1 + I2
+busbar_volume = BUSBAR_L * BUSBAR_W * BUSBAR_H
+
+# Ohmic Loss
+print(f"Ohmic Loss (Joule heating): {total_loss:.6f} W")
+
+# Loss density
+loss_density = (total_loss / busbar_volume) if busbar_volume else 0.0
+print(f"Loss density: {loss_density:.8f} W/mm³")
+
+# Equivalent DC resistance
+resistance = (total_loss / (total_current**2)) if total_current else 0.0
+resistance_micro = resistance * 1e6
+print(f"Equivalent DC resistance: {resistance_micro:.2f} µΩ")
+
+# Skin depth calculation
+mu0 = 4 * math.pi * 1e-7
+sigma_cu = 5.8e7
+omega = 2 * math.pi * FREQ
+skin_depth_m = math.sqrt(2 / (omega * mu0 * sigma_cu))
+skin_depth_mm = skin_depth_m * 1000
+print(f"Skin depth at {FREQ} Hz: {skin_depth_mm:.3f} mm")
+
+current_density = (total_current / (BUSBAR_W * BUSBAR_H)) if (BUSBAR_W * BUSBAR_H) else 0.0
+print(f"Average current density: {current_density:.2f} A/mm²")
+
+power_per_amp_squared = (total_loss / (total_current**2)) if total_current else 0.0
+print(f"Power per A²: {power_per_amp_squared*1e6:.2f} µW/A²")
+
+# Comparison with conductor thickness
+if BUSBAR_H < 2 * skin_depth_mm:
+    print(f"Note: Busbar thickness ({BUSBAR_H}mm) < 2×skin depth ({2*skin_depth_mm:.1f}mm)")
+    print(f"      Skin effect is significant - current distribution is non-uniform")
+else:
+    print(f"Note: Busbar thickness ({BUSBAR_H}mm) > 2×skin depth ({2*skin_depth_mm:.1f}mm)")
+    print(f"      Current flows mainly near surfaces due to skin effect")
+
+print("\n--- Field Plot Information ---")
+print("Current density magnitude (|J|): Shows current distribution")
+print("Electric field magnitude (|E|): Shows electric field intensity")
+print("Joule heating distribution: Shows power loss density")
+
+# ## Finish
+#
+# ### Save the project
+
+m3d.save_project()
+m3d.release_desktop()
+# Wait 3 seconds to allow AEDT to shut down before cleaning the temporary directory.
+time.sleep(3)
+
+# ### Clean up
+#
+# All project files are saved in the folder ``temp_folder.name``.
+# If you've run this example as a Jupyter notebook, you
+# can retrieve those project files. The following cell
+# removes all temporary files, including the project folder.
+
+temp_folder.cleanup()