Isolated three-port DC-DC converter with power and FSK-PSK signal composite modulation

This paper proposes a power-signal synchronous transmission (PSST) strategy based on composite frequency-shift keying and phase-shift keying (FSK-PSK) modulation for an isolated three-port DC-DC converter (TPC). By embedding dual-channel digital data into the carrier frequency and phase of the drive signal for the switches, the proposed method enables simultaneous transmission of electrical power and communication signals through a shared converter platform. The system architecture and modulation principles are analyzed, and an equivalent Δ-connected model is established to describe inter-port power relationships. A hybrid coherent demodulation scheme is further developed to parallelly extract both frequency- and phase-modulated data, achieving accurate reconstruction of the original information sequence. Simulation studies conducted in MATLAB/Simulink demonstrate that the proposed TPC maintains stable voltage regulation and reliable data recovery under load transients and input power fluctuations. The output voltage ripple remains below 1%, while demodulated signals show minimal delay and distortion. The results confirm that the proposed FSK-PSK-based PSST strategy effectively enhances the functional integration and communication capability of power electronic systems.