CODEWITHSUNDEEP
pythonpython-3.xnumpysympy
Kailash Kumawat
Kailash Kumawat

Reputation: 23

How to solve an equation which has a solution variable in form of function at both side of equation

I want to plot a graph of an equation in Python which has a solution variable at both sides in form of some function. The equation is:

i = Ip - Io*(exp((V+i*R1)/(n*Vt)) - 1) - (V +I*R1)/(R2)

where Ip, Io, n, R1, R2, Vt are some constants.

I want to iterate V in the range (0,10) and want to get values for i using Python and plot a V-i graph.

import numpy as np
from sympy import *
import matplotlib.pyplot as plt
r = 50
V = np.linspace(0,10,r)

def current():
    current = []
    for t in V:
        i = np.zeros(r)
        Ipv = 3
        Rs = 0.221
        Rsh = 415
        n = 2
        m = 1.5
        T = 302
        Eg = 1.14
        K = 1.3
        Vt = T/11600
        Io = K*(T**m)*exp(-Eg/(n*Vt))
        i = Ipv - Io *(exp((t + Rs*i)/(n*Vt)) - 1) - (t + Rs * i)/Rsh
        current.append(i)
    return np.array(current)

Icurrent = current()
plt.plot(V,Icurrent)
plt.show()

I did this but this not working.

Any suggestions welcome.

Upvotes: 0

Views: 213

Answers (1)

Mr. T
Mr. T

Reputation: 12410

It seems, your problem is that you mix numpy arrays with a scalar math function. Don't do this. Substitute it with the appropriate numpy function:

import numpy as np
import matplotlib.pyplot as plt
r = 50
V = np.linspace(0,10,r)
print(V)

def current():
    current = []
    for t in V:
        i = np.zeros(r)
        Ipv = 3
        Rs = 0.221
        Rsh = 415
        n = 2
        m = 1.5
        T = 302
        Eg = 1.14
        K = 1.3
        Vt = T/11600
        Io = K*(T**m)*np.exp(-Eg/(n*Vt))
        i = Ipv - Io *(np.exp((t + Rs*i)/(n*Vt)) - 1) - (t + Rs * i)/Rsh
        current.append(i)
    return np.array(current)

Icurrent = current()
plt.plot(V,Icurrent)
plt.show()

Output:
enter image description here

I would have suggested using scipy.fsolve, but seemingly your approach is working.

Upvotes: 1

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