Simultaneous Power and Data Transmission Using Combined Three Degrees of Freedom Modulation Strategy in DC–DC Converters

Power and signal dual modulation (PSDM) modulates both power and data at the same time, making it an appropriate communication method for power electronics’ applications. While the conventional PSDM schemes use either duty cycle control or phase/frequency control of the gate signal for switching devices, which achieve limited bitrate performances, this article proposes a novel PSDM scheme that combines the control of the three degrees of freedom (DoF) to further improve the bitrate. The scheme's feasibility is shown by examining the compatibility between the control of different DoFs from the perspective of communication. Then, a practical scheme is determined based on the analysis of the influence between signal carriers with different frequencies and the upper limit of M-ary modulation for each carrier. Finally, a 230 W experimental prototype, which achieves independence between power and communication control as well as a bitrate of 41.7 kb/s under the switching frequency of 100 kHz/83.3 kHz, demonstrates the correctness of the proposed scheme and the pertinent theoretical analysis.