The controller is not mandatory.
Most fans use under 1 amp. Many under .5 amps. Unless you are using powerful fans, you can normally connect 3 to a single header by splitters.
Any fan will run off the PSU if you have a Molex connector for the fan, rather than the standard tiny 3 pin or 4 pin connection. Molex connectors go directly to the PSU, unlike 3 pin or 4 pin connectors, which go to the motherboard.
If you use Molex connectors, you don't have to wonder if you might be overloading the motherboard fan header.