Power flow control in single-phase and three-phase grid-connected inverters using LMI, state-feedback linearization and D-stability

This paper proposes a methodology for the active and reactive power flow controls, applied at single-phase and three-phase inverters operating in grid-connected mode at low voltage. The converter´s control technique is based on Linear Matrix Inequalities (LMI) together with D-stability criteria and state-feedback linearization. The power flow control uses the power transfer curves (similarly to droop control) P-ω e Q-V, applied to a multi-loop control system. The multi-loop control uses the technique of state-feedback linearization in order to minimize the non linearities of system, improving the controller´s performance and mitigating potential system´s disturbs. Moreover, the purpose of the methodology is to obtain the best controllers with the lowest gains placing the poles in the left-half s-plane region specified during the design stage, resulting in fast responses with reduced oscillations. Finally, a 1000VA single-phase and one 3000VA three-phase prototypes were implemented in order to demonstrate the feasibility of the proposed control.