An Optimal Control Scheme for a Grid-Connected Inverter Under Measurement Noise

This brief addresses the optimal control issue of a three-phase grid-connected voltage source inverter under electromagnetic interference. Aiming to reduce the computational burden brought by the phase-locked loop, grid voltage modulation is used to transform the nonlinear inverter system into a linear system. A novel auxiliary variable is proposed to design a linear quadratic regulator, and the controller can exponentially stabilize the system globally. The nonlinear observer is used to estimate the grid voltage, and the unscented Kalman filter is utilized to filter the output of the nonlinear observer and the current sampling data. The control scheme proposed in this brief can achieve satisfactory transient and steady-state performance under severe electromagnetic interference. The simulation validates the theoretical analysis and the effectiveness of the proposed control scheme.