Amplitude-modulation tuned bidirectional simultaneous power and signal transmission

Abstract:

To address issues such as structural complexity, low transmission rates, and power-signal crosstalk in bidirectional power and signal synchronous transmission systems for inductive wireless power transfer, a novel bidirectional power-signal synchronous transmission method based on amplitude modulation and tuning is proposed. In this paper, the forward signal is amplitude-modulated by changing the phase shift angle of the inverter phase-shifted full-bridge control to achieve forward signal transmission. The reverse signal is tuned-modulated by changing the secondary resonant capacitance to achieve reverse signal transmission. This results in the current at both ends of the coil carrying signal characteristics. A current transformer is then used to feed the current signal with signal characteristics into the demodulation circuit to restore the signal. First, theoretical analysis of the circuit structure is conducted. Then, simulations are performed using Matlab/Simulink to verify the theoretical analysis. Finally, a 120 W experimental platform is constructed based on the simulation results. Experimental results demonstrate that at a power 120 W, the load voltage fluctuation is less than 3%, and the impact of power transmission on signal transmission is minimal. The system achieves half-duplex communication with a forward rate of 4 kbps and a reverse rate of 20 kbps at a bit error rate of 0.1%. Both experimental and simulation results confirm that this method effectively achieves bidirectional power and signal synchronous transmission in inductive wireless power transfer systems, offering high transmission rates and low bit error rates, which provide valuable guidance for wireless power transfer system design.