Quasi-Omnidirectional Wireless Power Transfer for a Sensor System

The wireless sensor networks play a vital role in the field of monitoring, which can be powered by the wireless charging technology. In this paper, we reported a sensor node charging system via Omni-directional magnetic coupling resonant technology based on the application background of using the unmanned aerial vehicle (UAV) for wireless charging in a hazardous industrial environment. The system on the UAV can charge rapidly the battery on the wireless sensor nodes in the high-risk working environments when the battery capacity is below the threshold. The system can select two most suitable transmitter (TX) coils to charge for the sensor nodes by the feedback control circuit based on the sensor node location. Angle misalignment of the transmitter coils is a problem for many practical applications. Therefore, And we also models and analyzes the transmitter coil deviations to meet the angle misalignment during actual applications. The efficiency variation caused by the deflection of the transmitting coil and the offset of the optimal operating point are analyzed. The result shows that the optimal efficiency point will change as the coil is deflected. Controlling the UAV to the optimal efficiency point can reduce the influences of the non-orthogonal transmitter coil on the efficiency. Moreover, the experiments show that the system achieves a maximum output power of 12 W. Thus, this system can be a good candidate for the power supply of wireless sensor nodes working in a special environment.