An apparatus and a method for wireless transmission of power between dc voltage sources

An apparatus for wireless transmission of power from a DC voltage source to a DC voltage load, comprising:

• a) one primary coil and one secondary coil, the primary coil and the secondary coil each connected with means of capacitors configured to achieve a common resonance frequency, ω0;
• b) said one primary coil and one secondary coil are mutually movable during operation;
• c) a DC/AC-converter converting the DC voltage at primary side to an AC voltage of controllable magnitude and frequency at the primary side;
• d) one rectifier at the secondary side converting the AC voltage at terminals of the secondary coil to a DC voltage at the load on the secondary side;
• e) a control system that regulates the power flow between the primary and the secondary coil and automatically adapts to changes in the mechanical positions of the two coils by changing in a coordinated way the magnitude and frequency of the AC voltage at the terminals of the primary coil during operation.

A method for wireless transmission of power from a DC voltage source to a DC voltage load, comprising the steps of:

• a. loosely coupling one primary coil with one secondary coil,
• b. equipping each with a series-connected resonant capacitor, so that the coil on the primary side resonates at the same frequency as the one on the secondary side;
• c. arranging said resonant coils on the primary side and the secondary side so that mutual movement during operation is possible;
• d. providing a DC/AC-converter converting the DC voltage at primary side to an AC voltage of controllable magnitude and frequency;
• e. providing a rectifier that converts the AC voltage at the terminals of the resonant pickup coil at the secondary side to a DC voltage;
• f. providing a control system that regulates the power flow between the primary and secondary coil and automatically adapts to changes in the mechanical positions of the two coils by changing in a coordinated way the magnitude and frequency of the AC voltage at the terminals of the primary resonant coil;
• g. providing a load at pickup-side that has constant-voltage characteristics.