# ECEN_405_Assignment_1

```ECEN 405 Assignment 1
Due: 16 March
Worth: 3%
1. A power electronics package is designed to handle 200W of power dissipation. Compare the
two values of the output power capability if the conversion efficiency is increased from 74%
to 91%.
2. Induction cooking based on power electronics is estimated to be 80% efficient compared to
55% for conventional electrical cooking. If the average home consumes 2kW-hrs of daily
using conventional electric heating and one million households switch to induction cooking,
calculate the annual savings in electricity usage.
3. In a buck converter, the input voltage is 12V. The output voltage is required to be 9V. The
switching frequency is 400Hz. Assuming ideal switching power pole, calculate the pulse
width of the switching signal and the duty ration of the power pole.
4. Describe the role of power electronics for energy conversion in lighting using CFLs and LEDs.
5. The circuit of the figure on page 7 of your ‘power computations’ notes on energy recovery
has Vcc = 90V, L=200mH, R=20Ω, t1=10ms, and T=100ms. Determine (a) the peak current
and peak energy storage in the inductor, (b) the average power absorbed by the resistor and
(c) the peak and average power supplied by the source.
6. On slide 33 of you lecture slides, lighting consumes 19% of the generated electricity. If an
average household in New Zealand uses 8600 KWh of electricity a year and we have 1.8
million private dwellings in our country, estimate the cost savings in consumption if all of the
lighting is replaced by LED bulbs.
```