Fully Controlled Bridge Rectifier

hi im doing a project at college and im trying to find out how to derive the equations for:

a) load voltage
b)supply current

for a circuit with and without a flywheel diode connected

can anyone help? im totally stumped with this

 

What is a flywheel diode?

 

Can you supply us with a circuit diagram to give us a clear picture of what you are working with?

hgmjr

 

A flywheel diode is often required, because when the current through an inductive load is suddenly broken, a back EMF will build up as the magnetic field breaks down, and if there is no path for the current, a high voltage builds up. The high voltage can damage a transistor or cause arcing in a switch. The flywheel diode is connected in reverse across the load, and provides a path for the current so the magnetic field and current can safely decline.

there is a copy of the circuit i am working with, sorry i dont know how to post images

http://services.eng.uts.edu.au/~venkat/pe_html/ch04s2/mathsim/cirdia5.gif

when the flywheel diode is attached it will be connected in parallel across the inductor and resistor

thanks for your help guys