At present, there is no long-term reliable power source for the sensors on underground three-phase or dc power cables. Thus, a lateral free rotation inductive power transfer (LFR-IPT) system is proposed to charge the power cable sensors. The idea of the proposed system is to use two partially overlapped receiving coils to construct the power receiver. This design ensures even with the rotation of the receiver, the magnetic flux of the transmitting coil passing through the receiving coils would not decrease to zero. Compared with a fully enveloping single cylindrical receiving coil, the proposed overlapped receiving coils require less material, consequently, lower expense, and offer relatively higher system efficiency. Specific rotation and scanning angles are designed for the proposed overlapped two coils, and a decoupling circuit is utilized to eliminate the impact of cross-coupling between the two receiving coils and simplify the system design. Two half-bridge rectifiers are series connected to improve the system output voltage. Thus, comprehensively, the output of the system can keep a relatively lateral rotation-independent characteristic. A prototype is built to validate the performance of the proposed system. Experiment results show that, with 50 cm transmitting distance, the output power of the system can remain larger than 1.64 W when the receiving coils rotate from 0° to 360°.

inductive power transfer,sensor,Cable,free rotation