Isolated DC-DC converter with hysteresis-based single phase-shift control

This paper explores a modulation strategy for controlling an isolated DC-DC power electronics converter. The employed scheme is based on a dual active bridge (DAB) converter with an H-bridge on each side. A step-down high-frequency power transformer provides isolation while maintaining the DCDC conversion. The control scheme uses a microcontroller to generate the commanding signal for the MOSFETs on each full-bridge (FB). However, an external analog signal is used as a reference instead of generating signals internally, simplifying implementation. The phase-shift angle ($\phi_{\mathrm{ct} 1}$) controls the output voltage, defined as the difference between the primary and secondary transformer phases. The primary side is manipulated by squared waveform while a hysteresis comparator controls the FB at the output side, then an analog controller generates the phase-shift angle. Besides, the expressions for the primary side leakage inductor are determined. Simulation results validate the approach in a closed-loop configuration, while experiments demonstrate its practical performance.