Control Architecture for Solid-state Transformer with Effective Power Sharing

The control architecture of solid-state transformers (SSTs) is vital for their sustainability and longevity. Features like fast transient response and reactive power support enhance SST reliability over conventional line-frequency transformerbased solutions for applications such as EV charging and grid storage, along with benefits such as high power density and modularity. Proper power routing (Note, here, power routing means the system’s capability of processing equal, unequal, and partial power considering the ageing of the devices and passive components) is essential for extending the system’s lifespan in modular SST designs. Effective reactive power distribution among the sub-modules is also crucial for system reliability and utilization. However, current literature often lacks robust control architectures that support efficient power routing and reactive power management among the sub-modules in SSTs. The control architectures discussed in the literature require highbandwidth sensors or some estimation algorithm to ensure equal power sharing. Also, this literature does not discuss reactive power support and its effective distribution in case of unequal or partial power sharing. This paper introduces a novel control architecture for SSTs that supports effective active and reactive power routing at the sub-modular level with detailed stability analysis of all loops. The proposed control architecture does not require additional sensors or estimation algorithms to ensure equal power sharing. Also, it ensures effective reactive power routing for partial or unequal active power processing. The proposed architecture and the equal power sharing algorithm are validated through simulation and experiment using a 1 kW, $230 \mathrm{~V}, 50 \mathrm{~Hz}$ (AC) to 250 V (DC) system.