Interesting to see your circuit.
Have you considered dumping the power into a battery or something?
At work we burn in power supplies and use loads which end up re powering the grid. Very nice compared to burning up 50kw in heat 24x7
Glad you found it of interest.
I had seen a post where a member had asked about using a switching load rather than linear and thought it may be interesting to play with. It wasn't. One thing that was mentioned was using a resistor to burn off the energy. For this circuit, the majority of heat is going to be in the IGBT and FRED. After that the inductor and 4-wire sense.
I had not considered doing anything with energy recovery. There's a pretty big benefit if you can recover some of your 50KW. This thing with that tiny heat sink is not going to handle any sort of power for any length of time. The circuit has so many disadvantages anyway, it really was a pointless effort. There was a post where someone mentioned feeding energy back into the supply being tested. I see no reason this could not be done.