A load-independent Class EF inverter may maintain ZVS operation, and produce a constant output current, rather than a constant output voltage, regardless of the load resistance. A constant output current allows the inverter to operate efficiently for a load range from zero resistance (short circuit) to a certain maximum load resistance, making the inverter more suitable as a coil driver for an IPT system. The resonant frequency of the resonant circuit may be tuned to a non-integer multiple of a switching frequency.