Homework Assignment 6
Solved study problems
ECEN 4797 assignment
- [50 pts] Textbook Problem 6.5
- [50 pts] Textbook Problem 6.6
ECEN 5797 assignment
- [50 pts] Textbook Problem 6.5
- [50 pts] Textbook Problem 6.6
- [50 pts] Textbook Problem 6.8
Notes and suggestions for this problem set:
- Problem 6.6: in accordance with normal practice for forward converter transformers, the transformer magnetizing inductance LM is very large, and hence the magnetizing current is very small.
Why: negligible magnetizing current in the forward converter is a result of how the transformers of these converters are normally designed (with no air gap and hence large LM -- a topic for later in the course). One could design the transformer to have significant magnetizing current as in a flyback converter (this is done by adding an air gap), but nothing good comes of it: the currents around the converter are increased, and there is more loss. There is an additional problem with significant magnetizing current in this problem: since LM operates in DCM in the conventional forward converter, it has large ripple and the small ripple approximation doesn't work. As a result, we can't use an averaged model to accurately calculate the losses induced by the magnetizing current. So you are asked to calculate losses assuming that the magnetizing current is negligible, which is how it is normally done in practice.