Power and Communication Decoupling for a Dual-Active-Bridge Converter With FSK-Based Talkative Power Conversion

Talkative Power Conversion (TPC), which can transfer power and data simultaneously using interfaced power electronics converters, eliminates the need for additional communications infrastructures. Frequency Shift Keying (FSK) is a classic TPC modulation used in DC-DC converters, of which the Dual Active Bridge (DAB) converter is one of the most popular topologies. However, a DC bias in inductor current is generated by the FSK, and such phenomenon is caused by the coupling of power and communication. This coupling effect, which has been ignored in literature so far, will cause magnetic saturation, degrading the performance of the DAB converter and resulting in overcurrent issues. In this paper, a power and communication decoupling method is proposed for DAB converters with FSK-based TPC to eliminate the DC bias inductor current. A mathematical model of the DC bias inductor current with switching frequencies, phase shift ratio and circuit parameters is developed. According to the model, a regulation of the phase shift ratio is proposed to decouple the power and communication. The effectiveness of the proposed decoupling method for DC bias inductor current elimination as well as the TPC performance are verified by simulations and experiments.