The most usual kind of motor with permanent magnets, is just a synchronous motor, where, in order to remove the power supply needed by the rotor windings, the rotor windings are replaced by permanent magnets.

Here, in order to achieve the same brushless operation like when using permanent magnets, the rotor windings are kept, but the electrical current needed by them is transmitted to the rotor wirelessly.

For this to work, I suppose that the rotor includes some kind of semiconductor rectifiers and the rotor current is induced at a frequency much higher than the rotation frequency.

This should indeed have characteristics similar to the permanent magnet motors, except that it is not clear if the energy efficiency can be equally good.

A permanent magnet rotor is equivalent with a rotor having superconducting windings, so it has no losses due to the electrical excitation currents (though it may have losses due to other causes, e.g. hysteresis and eddy currents).

This motor will have extra losses in the copper windings of the rotor and in whatever kind of rectifiers it uses.

Nevertheless, perhaps these extra losses are small, so the efficiency can be much higher than that of asynchronous motors (like initially used by Tesla) and only a little lower than that of the permanent magnet motors.