125 lines
3.4 KiB
Python
125 lines
3.4 KiB
Python
#!/usr/bin/env python3
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# -*- coding: utf-8 -*-
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"""
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Created on Fri Apr 26 00:50:35 2019
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@author: oyvind
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"""
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import math
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import numpy as np
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import matplotlib.pyplot as plt
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# Name for the saved graph
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filename = "SimuleringPy"
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#RPM to simulate
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RPM = 40000
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#RPM to calculate tau
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tauRPM = 40000
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# Forward voltage of the diode
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forwardVoltage = 0.7
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# Threshold voltage of the transistor
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thresholdVoltage = 2
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# Upper voltage of the pulsetrain
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upperVoltage = 5
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# How many cycles you want it to run
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cycles = 5
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# The resolution of each cycle
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resolution = 2000
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# Converting from RPM to Hz and period in seconds and milliseconds
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def RPMtoPeriod(rpm):
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Hz = rpm / 60.0
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period = 1 / Hz
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periodmS = period * 10**3
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return periodmS
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periodmS = RPMtoPeriod(RPM)
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print("Period in ms: " + str(periodmS))
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# Calculates the tau based on the period, and the different voltages
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def CalculateTau():
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# Calculate the roots of the tau-equation
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roots = np.roots([forwardVoltage, -upperVoltage, upperVoltage - thresholdVoltage])
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# Calculate the possible taus
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taus = -(RPMtoPeriod(tauRPM)) / (2 * np.log(roots))
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print(taus)
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# Discard the non-real tau
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if taus[0] > taus[1] and taus[0] > 0:
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return taus[0]
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return taus[1]
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# Just creates a pulsetrain with some voltage and duty-cycle
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def GeneratePulsetrain(voltage = 5, dutyCycle = 0.5):
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pulseTrain = []
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for i in range(cycles):
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for i in range(round(resolution * 2 * dutyCycle)):
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pulseTrain.append(voltage)
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for i in range(round(resolution * 2 * (1 - dutyCycle))):
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pulseTrain.append(0)
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return pulseTrain
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# Generate the time-signatures from the number of cycles, the resolution and
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# the periodtime. result in milliseconds
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def GenerateTime():
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times = []
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for t in range(cycles * resolution * 2):
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times.append(periodmS * t / (resolution * 2))
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return times
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def OutVoltage(wave, times):
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cP = wave[0] # Start voltage-supply
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v0 = 0 # Start voltage
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cT = 0 #Start time
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volt = []
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for p in range(len(wave)):
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# If the voltage-supply changes, recalculate startvalues
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if wave[p] != cP:
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v0 = volt[-1] # New start voltage, uses the last voltage calculated
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if wave[p] == 0:
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v0 = forwardVoltage
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cP = wave[p] # Variable so the array is not accessed.
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cT = times[p] # Offset time for each period
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# Calculate the outgoing voltage over the CAPACITOR with the start values
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volt.append(cP + (v0 - cP) * math.exp(-(times[p] - cT) / tau ))
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return volt
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def GenerateThreshLine(times):
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thresh = []
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for i in times:
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thresh.append(thresholdVoltage)
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return thresh
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# Calculate Tau
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tau = CalculateTau()
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print("Tau in ms: " + str(tau))
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# Generate all the lists of pulsetrain and time-signatures
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time = GenerateTime()
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pulse = GeneratePulsetrain(upperVoltage)
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threshLine = GenerateThreshLine(time)
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# Simulate the outgoing voltage
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voltage = OutVoltage(pulse, time)
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plt.figure(figsize=(12,5))
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plt.plot(time, pulse)
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plt.plot(time, voltage)
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plt.plot(time, threshLine, 'k--')
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plt.title("Spenningsutvikling ved " + str(RPM) + " RPM. Grensefrekvens er " +
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str(tauRPM) + " RPM.")
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plt.xlabel("Tid [ms]")
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plt.ylabel("Spenning [V]")
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plt.legend(["Pulstog, " + r'$v_1$', "Utgående spenning, " + r'$v_2$', "Terskelspenning, " + r'$V_T$'], loc="upper right")
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plt.savefig(filename + ".png", dpi = 300)
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plt.show()
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