"...170V with 100 amp output..."

Crikey.

A boost is not a good topology for 17kW. Assuming you'll get about 95% efficiency, you're dealing with almost 400 Amps in the primary. I would spend some time performing some topology studies.
Here are just a few suggestions for study: A single full-bridge using one of those Infineon water-cooled bridge modules, Multiple SMPS all tied together such as: multiple full bridge, half bridge, or auto transformers.

Darrell Hambley P.E.
SENTEK Engineering, LLC

In addition to what DHambley posted, you may also need a multi-phase approach to keep input ripple down and synchronous rectification for better efficiency than regular diodes.

The boost converter is a perfectly fine topology for very high power, but it becomes less attractive as the ratio of output voltage to input voltage rises. To boost 48V to 170V (sounds like the front end of a very large 120VAC inverter) you will need to run the switch at a duty cycle of 70-75%; at this point you really ought to use a transformer (or perhaps an autotransformer - aka a "tapped inductor boost") to assist with the voltage multiplication and, perhaps, a multiphase/interleaved approach to reduce current stresses.

Besides a multiphase/interleaved boost (and likely 8+ phases) I would consider using multiple 2-switch forward converters or a single current-mode push-pull. The latter two choices especially if isolation between the 48V and 170V sides is needed.