I think you need to explain a bit more what you want to do.
Do you need the device to just dissapear from the host machine? Do you need to actually cut USB power to the device. Is this a device on the end of a fiber USB cable so that cutting power to one end doesn't cut the power on the other end?
In general you can get fancy USB hubs that are "managed" in that a piece of software can see what is in the ports, see power consumption on each port, cut power to it etc.. Tho expect to pay a fair bit more for such a hub compared to the cheep Chinese garbage hubs that you find in computer stores.