Frequency Division Multiplexing-based Power/Signal Synchronous Transmission Strategy for IPOS-DAB DC/DC Converters

Modular input-parallel-output-series dual active bridge (IPOS-DAB) DC/DC converters have been frequently used in electric vehicles, energy routers, and other fields due to their high control flexibility, bidirectional operations, and high power density. Reliable communication is the basis for secure and stable power conversion, but the multi-module system faces many types of communication security threats. In an attempt to address this issue, a frequency division multiplexing (FDM)-based power/signal synchronous transmission (PSST) strategy realized by IPOS-DAB converters is proposed in this article. The DC power bus is utilized as a multiplexed signal transmission medium to realize high power and high bit-rate signal synchronous transmission. The constraints of IPOS-DAB converters with different switching frequencies are derived, together with the peak-to-peak value and fundamental amplitude of output voltage ripples. Then, the expression of the sending signals for the proposed FDM-based PSST strategy is obtained, and signals can be demodulated under a low signal-to-noise ratio (SNR) according to the sign of the designed demodulation criterion based on the coherent demodulation. The effectiveness of the proposed strategy is validated by experimental results in steady-state and transient operations.