The magnetic coupled wireless power transfer driver based on adjustable gain constant-current compensation network

� 2016, The editorial office of Transaction of China Electrotechnical Society. All right reserved. Due to the large leakage inductance of the loosely coupled transformer, compensation technology is crucial to improve the transfer efficiency in the magnetic coupled wireless power transfer (WPT) system. In the light-emitting diode (LED) lighting application, the WPT LED driver should provide not only the required LED current directly, but also zero reactive power, low device stress and soft switching. Compared with the conventional compensation network whose output current gain relies on the transformer parameters significantly, as well as the loosely coupled transformer with the constrained design,a family of novel constant-current compensation network using two-port network theory was proposed in this paper, where high freedom of current gain and transformer design were achieved by adjusting the compensation parameters. The prototypes with the same circuit topology and transformer were built to realize the output current of 0.5A, 1A, 1.5A, respectively, which agreed well with the theoretical analysis. Characteristics of these compensation networks were also analyzed in detail.