Switching

The figure below shows a composite power switching device and the current through it under steady state. The MOSFET of the switching device has an ON state resistance of $10\,$m$\Omega$. The ON state voltage drop across the diode of the switching device is $1\,$V . The current passing through the device is a periodic half sine wave as shown below. What is the average power loss in the composite device in Watts?
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from IPython.display import Image
Image(filename =r'switching_6_fig_1.png', width=500)
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No description has been provided for this image
In [2]:
import numpy as np
import matplotlib.pyplot as plt 
import gseim_calc as calc
from setsize import set_size

Im  = 50.0
T   = 20e-3
Rd  = 10.0e-3
Von = 1.0

n_div = 2000
t = np.linspace(0.0, T, (n_div+1))

omg = 2.0*np.pi/T
Tb2 = T/2

I = np.where(t < Tb2, Im*np.sin(omg*t), 0.0)

P_Rd  = I*I*Rd
P_Von = 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(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, 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 right',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:  2.2165E+01 W
No description has been provided for this image

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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