Patent ID: 8749097

Claim:
A signal transfer system for controlling inductive power transfer between a primary inductive coil and a secondary inductive coil, the primary inductive coil being connected to a reception circuit configured to detect a plurality of control signals and the secondary inductive coil being connected to an electrical load and a transmission circuit configured to transmit said plurality of control signals, wherein the transmission circuit comprises at least one ancillary load selectively connectable to the secondary inductive coil and further comprises a switching unit for intermittently connecting the ancillary load to the secondary inductive coil, wherein said control signal is generated by the ancillary load being intermittently connected to the secondary coil at a determined rate; wherein the transmission circuit further comprises a half-wave rectifier, and a reception circuit configured to detect second harmonic signals in the power supplied to the primary inductive coil; and wherein a plurality of primary inductive coils are connected to a driver, the driver being configured to operate the primary inductive coils sequentially, and the reception circuit is configured to detect second harmonic signals in the power supplied to at least one primary inductive coil, indicating that the primary inductive coil is coupled to a secondary inductive coil.