Wireless power transfer systems in accordance with embodiments of the invention are disclosed. In one embodiment, a wireless power transfer system includes a power transmitter driven by an oscillator, a power receiver including a resistive load, and a coupled resonator link configured to deliver power from a transmitter tank circuit to a receiver tank circuit, wherein the free-running oscillator automatically tunes to oscillate at a frequency that does not experience a phase shift due to the impedance of the transmit side of the coupled resonator link, wherein the power transmitter provides regulated voltage across a range of distances between the transmitter tank circuit and the receiver tank circuit, and wherein the power transmitter regulates voltage across a range of resistive loads of the power receiver.