48 lines
1.2 KiB
Python
48 lines
1.2 KiB
Python
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import numpy as np
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import matplotlib.pyplot as plt
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from scipy.signal import TransferFunction, lsim
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# ---- Parameters (edit these) ----
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R = 1.5 # ohms
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L = 0.0025 # henries
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V = 12.0 # volts
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# Time base
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t_end = 0.2
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dt = 1e-4
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t = np.arange(0, t_end, dt)
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# ---- Define a duty command D(t) ----
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# Example: start at 0, step to 0.2 at 20 ms, then to 0.6 at 80 ms, then to 1.0 at 140 ms (DC full on)
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D = np.zeros_like(t)
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D[t >= 0.020] = 0.2
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D[t >= 0.080] = 0.6
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D[t >= 0.140] = 1.0 # "straight DC" case (100% duty)
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# Clamp just in case
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D = np.clip(D, 0.0, 1.0)
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# ---- Transfer function I(s)/D(s) = V / (L s + R) ----
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# In scipy.signal.TransferFunction, numerator/denominator are polynomials in s
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G = TransferFunction([V], [L, R])
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# Simulate i(t) response to input D(t)
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tout, i, _ = lsim(G, U=D, T=t)
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# ---- Print steady-state expectations ----
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# For constant duty D0, steady-state i_ss = (V/R)*D0
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print("Expected steady-state currents (V/R * D):")
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for D0 in [0.0, 0.2, 0.6, 1.0]:
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print(f" D={D0:.1f} -> i_ss ~ {(V/R)*D0:.3f} A")
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# ---- Plot ----
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plt.figure()
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plt.plot(tout, D, label="Duty D(t)")
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plt.plot(tout, i, label="Current i(t) [A]")
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plt.xlabel("Time [s]")
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plt.grid(True)
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plt.legend()
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plt.show()
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