IDA-PBC controller design for grid connected Front End Converters under non-ideal grid conditions

A passivity-based non-linear controller design for three-phase front-end converters used to connect renewable energy sources to the grid is proposed in this paper. The control objective is to inject all the generated power to the grid, while adjusting the reactive power exchanged with the power system. Besides, generated currents must have very low distortion, in order to satisfy the standards, even when grid voltages are distorted or unbalanced. The proposed controller is first designed using the Interconnection and Damping Assignment strategy, which allows obtaining controller parameters while ensuring the closed-loop system stability. In order to ensure that the output currents have very low harmonic distortion, the obtained control laws are modified based on the fundamental positive sequence grid voltage, obtained from a positive sequence detector. The proposal allows controlling both injected powers and DC-link voltage, from a unique controller design. Simulation and experimental results are presented to validate the proposed controller.