Bidirectional Simultaneous Wireless Information and Power Transfer via Sharing Inductive Link and Single Switch in the Secondary Side

In wireless power transfer (WPT) system, communication between the primary and the secondary plays an important role in system status monitoring and operation control. Bidirectional information transmission is also essential to detect the working state and send control command in both sides. This article proposes a bidirectional simultaneous wireless information and power transfer method. The secondary has a simple structure and employs only one switch. The proposed WPT system can achieve bidirectional information transmission via a sharing inductive link. The forward information is transferred by using a single full bridge inverter based on selected harmonic elimination PWM (SHEPWM) control methods without other high-frequency signal sources. In the secondary side, uncontrolled rectifier and a parallel MOSFET are adopted to realize constant voltage output and backward information transfer. The backward information modulation is achieved by changing the switching frequency of MOSFET. The forward and backward information demodulation modules are designed and analyzed in details. A 30W experiment platform with forward communication rate 5 kbps and backward communication rate 10 kbps is built to verify this proposed method.