I've been rewatching Doctor Who and I recently discovered something that has confused me about the TARDIS. In the classic and new Doctor Who, the Eye of Harmony is stated to be a limitless power source. Yet, the Doctor has been seen multiple times recharging/refueling the TARDIS using something called rift energy. In other instances, the TARDIS has completely lost power due to it being in "the wrong universe". And then on other occasions, the Doctor referred to artron energy as the main power source of the TARDIS.
What exactly powers the Tardis - is it ripped energy, or time vortex energy, or the Eye of Harmony, artron energy or a combination of these?