janik
06c62e04f8
DC/AC resistance, power dissipation, and via/injection-area currents of copper zone fills. KiCad 10 IPC-API plugin (kicad-python/kipy): multi-layer via-coupled FDM solver, multi-part terminals via User.1/User.2 marker layers, pads as contacts, uniform-injection and equipotential contact models, per-foil skin effect, optional solder/copper buildup on mask openings. 54-case test suite incl. exact analytic references. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
125 lines
4.8 KiB
Python
125 lines
4.8 KiB
Python
import numpy as np
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import pytest
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from fill_resistance import config, raster, solver
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from tests.util import NM, make_problem, strip_problem
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def _solve(problem, h_mm, i_test=1.0):
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stack = raster.rasterize_stack(problem, h_mm * NM)
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e1, e2 = raster.electrode_masks(stack, problem)
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return solver.run_solve(problem, stack, e1, e2, i_test,
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contact_model="equipotential"), stack
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def test_uniform_strip_exact_discrete():
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"""Full-width electrodes on a uniform strip: every row is an identical
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series chain, so the discrete solution is exact:
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R = (n_free_columns + 1) / (n_rows * sigma_s)."""
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p = strip_problem(length=50, width=10, e_len=5)
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res, stack = _solve(p, 0.5)
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n_free_cols = int(round((50 - 2 * 5) / 0.5)) # 80
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n_rows = int(round(10 / 0.5)) # 20
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r_exact = (n_free_cols + 1) / n_rows / p.sigma_s(0)
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assert res.R_ohm == pytest.approx(r_exact, rel=1e-9)
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assert res.mismatch_rel < 1e-10
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r_cont = p.rho_ohm_m * 0.0405 / (0.010 * 70e-6)
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assert res.R_ohm == pytest.approx(r_cont, rel=1e-6)
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def test_strip_R_independent_of_h():
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p = strip_problem(length=50, width=10, e_len=5)
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for h in (1.0, 0.5, 0.25):
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res, _ = _solve(p, h)
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m = int(round(40 / h))
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rows = int(round(10 / h))
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assert res.R_ohm == pytest.approx((m + 1) / rows / p.sigma_s(0),
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rel=1e-9)
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def test_partial_electrode_constriction():
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full = strip_problem(length=50, width=10, e_len=5)
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partial = make_problem(
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[([(0, 0), (50, 0), (50, 10), (0, 10)], [])],
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rect1_mm=(0, 4, 5, 6),
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rect2_mm=(45, 4, 50, 6))
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r_full, _ = _solve(full, 0.25)
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r_a, _ = _solve(partial, 0.25)
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r_b, _ = _solve(partial, 0.125)
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assert r_a.R_ohm > r_full.R_ohm * 1.05
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assert abs(r_a.R_ohm - r_b.R_ohm) < 0.01 * r_b.R_ohm
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def test_l_shape_corner_squares():
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"""Right-angle bend of equal-width arms: corner square counts as
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~0.559 squares (conformal-mapping result), within 5% at a fine grid."""
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w = 10.0
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outline = [(0, 0), (30, 0), (30, 30), (20, 30), (20, 10), (0, 10)]
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p = make_problem([(outline, [])],
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rect1_mm=(0, 0, 2, 10),
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rect2_mm=(20, 28, 30, 30))
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res, _ = _solve(p, 0.125)
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a_sq = (20 - 2) / w
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b_sq = (28 - 10) / w
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r_expect = (a_sq + b_sq + 0.559) / p.sigma_s(0)
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assert res.R_ohm == pytest.approx(r_expect, rel=0.05)
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def test_hole_increases_resistance_and_converges():
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solid = make_problem([([(0, 0), (40, 0), (40, 20), (0, 20)], [])],
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rect1_mm=(0, 0, 2, 20), rect2_mm=(38, 0, 40, 20))
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holed = make_problem(
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[([(0, 0), (40, 0), (40, 20), (0, 20)],
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[[(15, 5), (25, 5), (25, 15), (15, 15)]])],
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rect1_mm=(0, 0, 2, 20), rect2_mm=(38, 0, 40, 20))
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r_solid, _ = _solve(solid, 0.25)
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r_a, _ = _solve(holed, 0.25)
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r_b, _ = _solve(holed, 0.125)
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assert r_a.R_ohm > r_solid.R_ohm * 1.1
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assert abs(r_a.R_ohm - r_b.R_ohm) < 0.01 * r_b.R_ohm
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def test_cg_path_matches_direct(monkeypatch):
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p = strip_problem(length=50, width=10, e_len=5)
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r_direct, _ = _solve(p, 0.25)
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monkeypatch.setattr(config, "SPSOLVE_MAX_UNKNOWNS", 0)
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r_cg, _ = _solve(p, 0.25)
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assert r_cg.solve_info.method == "cg+jacobi"
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assert r_cg.R_ohm == pytest.approx(r_direct.R_ohm, rel=1e-6)
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assert r_cg.mismatch_rel < 1e-5
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def test_current_density_and_potential_scale():
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"""Uniform strip at 1 A: |J| in the free region equals I/(W t); the
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potential span equals R * I."""
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p = strip_problem(length=50, width=10, e_len=5)
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res, stack = _solve(p, 0.5)
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j_expect = 1.0 / (0.010 * 70e-6)
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ny, nx = stack.shape2d
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assert res.Jmag[0, ny // 2, nx // 2] == pytest.approx(j_expect, rel=1e-6)
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assert np.nanmax(res.V) == pytest.approx(res.R_ohm, rel=1e-9)
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def test_test_current_scaling():
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"""V and J scale linearly with I_test, power quadratically; R fixed."""
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p = strip_problem(length=50, width=10, e_len=5)
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r1, _ = _solve(p, 0.5, i_test=1.0)
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r10, _ = _solve(p, 0.5, i_test=10.0)
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assert r10.R_ohm == pytest.approx(r1.R_ohm, rel=1e-12)
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assert np.nanmax(r10.V) == pytest.approx(10 * np.nanmax(r1.V), rel=1e-9)
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assert np.nanmax(r10.Jmag) == pytest.approx(10 * np.nanmax(r1.Jmag),
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rel=1e-9)
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assert r10.P_total == pytest.approx(100 * r1.P_total, rel=1e-9)
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def test_power_identity():
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"""Sum of edge powers equals I^2 R exactly for the direct solve."""
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p = make_problem(
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[([(0, 0), (40, 0), (40, 20), (0, 20)],
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[[(15, 5), (25, 5), (25, 15), (15, 15)]])],
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rect1_mm=(0, 0, 2, 20), rect2_mm=(38, 0, 40, 20))
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res, _ = _solve(p, 0.25, i_test=40.0)
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assert res.power_balance_rel < 1e-9
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assert res.P_total == pytest.approx(40.0 ** 2 * res.R_ohm, rel=1e-12)
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assert res.P_vias == 0.0
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