Three-phase unfolding-based architectures offer a more efficient and power-dense alternative to multi-stage converters for grid-tied applications, but their lack of bulk energy storage limits reactive power support. This work proposes an auxiliary converter that circulates only partial power to regulate grid reactive power, thereby overcoming this limitation without sacrificing efficiency or power density. The main challenges of operating under time-varying dc voltages and selecting a suitable topology are addressed, with the proposed approach validated through simulations and a 1~kW prototype. This integration expands the functionality of unfolding architectures by enabling energy storage and reactive power control.
