Triple-active Bridge DC-DC Converter Control for PV and ESS Integration in DC Microgrid Applications

This paper proposes the control methodology for DC microgrids integrating diverse energy sources such as photovoltaic (PV) and Energy Storage Systems (ESS). In remote microgrids, ESS play a crucial role in balancing power by compensating for variations in PV generation. Multi-port converters, like the Triple Active Bridge (TAB), offer benefits such as galvanic isolation and bidirectional power flow. This work utilizes a TAB converter to provide regulated DC bus voltage while concurrently managing power sharing between ESS and PV, implementing a decoupled power flow strategy for effective regulation of the output DC voltage. A control-focussed converter model based on generalized harmonic approximation (GHA) is formulated, which is used to obtain multiple transfer functions. The TAB converter’s transfer functions are validated by employing switching simulations in PLECS, utilizing multitone analysis. Experimental results validating the analytical model are shown and discussed using a prototype of a TAB converter.