I've looked at the designs of switching power supplies (buck/boost/buck-boost) and I basically understand how they work. But is this the same thing used in large power supplies such as those in the VFD of a tower crane (etc.)? Like the larger of the two hoist winches offered for the Liebherr 710 HCL 25/50 tower crane, which uses a 220 kW (294 H.P.) AC motor. How does the power supply maintain DC output while the motor is bogged out to ~18% of full speed?** Do large VFD's and whatnot still use a conventional buck (boost) switching converter to get the required "rail voltage"?
Note that 480 Vrms coming in gets you approx. 680 VDC through the rectifier and reservoir capacitors.
**Here's part of the performance data if anyone wants to know:
0 - 3450 kg*** at 0 - 238 m/min (0 - 6900 kg at 0 - 119 m/min)
0 - 25000 kg at 0 - 43 m/min (0 - 50000 kg at 0 - 22 m/min)
***238 m/min only goes up to 1800 kg on 1-part line if the reduced speed curve is used.