The use of real-time digital simulation (RTDS) has become an effective alternative for validating control and power flow strategies in modular power converters for low-voltage (LV) distribution networks, especially when full-scale testing is not feasible or rapid prototyping is required. However, conventional switched models of bidirectional AC-AC converters impose high computational loads that make them unsuitable for real-time execution on HIL platforms. This paper addresses this limitation by developing a large-signal dynamic model tailored for RTDS applications, enabling accurate and efficient emulation of the converter’s behavior under dynamic conditions. The model is designed to support hardware-in-the-loop validation of embedded control algorithms and system-level coordination strategies. As a case study, the proposed method is applied to a three-stage SST architecture composed of T-Type converters and a Dual Active Bridge (DAB), commonly adopted in modular 30 kW converter systems for LV applications such as electric vehicle charging and distributed energy integration.