Power required for h2, 70 F, 150 ACFM, 40 barg inlet, 41 barg outlet, 80% isentropic efficiency is about 12 hp.
Problem you've probably already come up against is that there aren't any off-the-shelf machines like this. Pressure is relatively high. The pressure ratio is fine, but the 40 bar part is going to make it a real odd-ball. A conventional blower manufacturer isn't going to touch this.
Centrifugal compressors can be made to handle higher pressures. And recips could easily be made to do this service. Another attractive option is a diaphragm machine because it has no dynamic seals. If this is for a process that runs non-stop, then consider a custom made centrifugal. If the process duty is intermittent or will only be used for a year or two and then dismantled, consider a diaphragm machine or a recip. The recip is going to be a less expensive option but with seal issues. Either way, hydrogen will need to be captured as it gets past the seals on a centrifugal or recip. That gas must be routed to a vent stack or possibly to some location where it can be compressed and put back into the process.
I suspect you won't find anything 'off-the-shelf' in a centrifugal. If that's what you're after, you'll need to contact manufacturers that do 1-off machines such as http://www.airproducts.com/Products/Equipment/CryoMachinery/default.htm" . You'll need to call them or email your needs. If you consider a diaphragm or recip machine, consider using a triplex to even out the pulsating flow of a single cylinder. There, I'd suggest RIX, Greenfield, PDC, Burton Corblin, lots of others.