Simultaneous Wireless Power and Data Transfer System With Single Coil Based on Multifrequency Modulation

The existing energy modulation simultaneous wireless power and data transfer (EM-SWPDT) system will cause severe load voltage drop and power efficiency reduction at the data transmitting. Besides, those methods can only achieve simplex communication. To solve these problems, this article proposes a single coil half-duplex communication EM-SWPDT system using a novel multifrequency modulation, which can enhance data transmission performance. By modulating the conduction angle of the converter with desired signal frequency, the steady state and sinusoidal fluctuating states are realized, which compose different data wave, respectively. Because the data transmission relies on frequency information instead of amplitude information, the load voltage drop can be reduced. And the phase-shifting equivalent current model is constructed to evaluate the influence of data transmission on load voltage. Since the data modulation is performed by the converters of wireless power transfer system, additional auxiliary data circuits, such as signal generators and wave trappers are omitted and branch crosstalk is reduced. Therefore, the influence of data transmission on power transmission efficiency is weak. Finally, the effectiveness of the proposed EM-SWPDT system with a novel multifrequency modulation is verified by experimental platforms.