Decentralized Secondary Frequency Control of Autonomous Microgrids via Adaptive Robust L2-Gain Performance

This paper presents an innovative passivity-based L2-gain performance (L2-GP) adaptive robust control method for the design of primary and secondary frequency control in the low-inertia microgrid with lines and the inverter-interfaced generation. First, by exploiting and analyzing the internal structural properties, the Port-controlled Kuramoto-Hamiltonian model with dissipation for the microgrid system is derived. Combining the dynamics of Kuramoto oscillators with energy viewpoints and following the physical features of dynamic energy coordination in the microgrid, an adaptive robust L2-GP decentralized secondary control is developed to guarantee frequency restoration and active power sharing. An adaptive mechanism is adopted to estimate the electrical parameters so that the parameter randomness can be overcome and fast transient response, high performance, and robust stability can be achieved. Via local measurements, the decentralized framework accordingly obviates the need of any communication links for information broadcast or exchange. Finally, the comprehensive case studies are presented to validate satisfactory performance under rapid randomness and flexibility during plug-and-play operations.