Low-Cost Embedded Hardware-in-the-Loop Validation of Bidirectional Converter Control in Hybrid Microgrids

Converter-dominated hybrid microgrids rely on digitally implemented control strategies that are commonly validated using offline simulation. However, such approaches cannot capture practical real-time implementation effects, including sampling delay, quantization, and computational latency. Although hardware-in-the-loop (HIL) platforms provide more realistic validation, conventional systems are often costly and inaccessible for early-stage research.This paper presents a low-cost embedded HIL framework for validating bidirectional converter control in hybrid microgrids. A dual-DSP architecture is employed, where one processor executes the control algorithms while the second emulates the microgrid plant using a reduced-order switching-state-free model. The plant model incorporates an LCL filter with damping and an equivalent RL load representation, enabling dominant converter dynamics to be captured with real-time execution on low-cost hardware.Two representative control strategies, namely droop control and virtual synchronous generator (VSG) control, are implemented and evaluated under realistic operating conditions. Experimental results show that the proposed platform reproduces the dominant converter dynamics with good agreement with offline simulation, while minor discrepancies arising from sampling delay and computational latency remain observable, particularly under VSG control. The proposed system achieves comparable dynamic fidelity to conventional HIL platforms at significantly lower hardware cost, providing a practical intermediate validation stage between simulation and full-scale experimental deployment.