Switching
The periodic current through a power diode in a particular application is given below. The power diode in the ON state can be modelled as a voltage source of magnitude $0.7\,$V in series with a resistance of $0.5\,$m$\Omega$. For $I_1 = 100\,$A, $t_1 = 0.2\,$ms, $T = 1\,$ms, find $I_2$ if the average power loss in the diode is $53.6\,$W.In [1]:
from IPython.display import Image
Image(filename =r'switching_7_fig_1.png', width=350)
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In [2]:
import numpy as np
import matplotlib.pyplot as plt
import gseim_calc as calc
from setsize import set_size
I1 = 100.0
I2 = 50.0 # to be changed by user
t1 = 0.2e-3
T = 1e-3
Rd = 0.5e-3
Von = 0.7
n_div = 2000
t = np.linspace(0.0, T, (n_div+1))
l_I = []
slope_I = (I1-I2)/(T-t1)
for i, tx in enumerate(t):
if tx < t1:
I = 0.0
else:
I = I1 - slope_I*(tx-t1)
l_I.append(I)
np_I = np.array(l_I)
P_Rd = np_I*np_I*Rd
P_Von = np_I*Von
P = P_Rd + P_Von
P_avg = np.trapz(P, t)/T
print('P_avg:', "%11.4E"%P_avg, 'W')
plot_min_P, plot_max_P = calc.delta_plot_1(P , 0.2)
plot_min_I, plot_max_I = calc.delta_plot_1(np_I, 0.2)
color1='red'
color2='green'
color3='dodgerblue'
color4='tomato'
fig, ax = plt.subplots(2, sharex=False, gridspec_kw={'height_ratios': [1, 3]})
plt.subplots_adjust(wspace=0, hspace=0.0)
set_size(6.5, 5, ax[0])
for i in range(2):
ax[i].set_xlim(left=0.0, right=T*1e3)
ax[i].grid(color='#CCCCCC', linestyle='solid', linewidth=0.5)
ax[0].set_ylim(bottom=plot_min_I, top=plot_max_I)
ax[1].set_ylim(bottom=plot_min_P, top=plot_max_P)
ax[0].set_ylabel(r'$i$', fontsize=12)
ax[1].set_ylabel(r'$P$', fontsize=12)
ax[0].tick_params(labelbottom=False)
ax[0].plot(t*1e3, np_I , color=color1, linewidth=1.0, label="$i$")
ax[1].plot(t*1e3, P , color=color2, linewidth=1.0, label="$P$")
ax[1].plot(t*1e3, P_Rd , color=color3, linewidth=1.0, label="$P_{Rd}$")
ax[1].plot(t*1e3, P_Von, color=color4, linewidth=1.0, label="$P_{Von}$")
ax[1].set_xlabel(r'time (msec)', fontsize=12)
ax[1].legend(loc = 'upper left',frameon = True, fontsize = 10, title = None,
markerfirst = True, markerscale = 1.0, labelspacing = 0.5, columnspacing = 2.0,
prop = {'size' : 12},)
#plt.tight_layout()
plt.show()
P_avg: 4.4315E+01 W
This notebook was contributed by Prof. Nakul Narayanan K, Govt. Engineering College, Thrissur. He may be contacted at nakul@gectcr.ac.in.
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