A Novel Finite-Time Settling Control Algorithm Designed for Grid-Connected Three-Phase Inverter With an LCL-Type Filter

In this paper, a cost-effective finite-time settling current control system for a utility-interactive three-phase voltage source inverter system with an inductor-capacitor-inductor (LCL)-type filter is originally designed and developed. The discrete-time system equation of the LCL-type filter is first simply derived in the α-β stationary reference frame. Then, the finite time of a three-sampling-period settling control algorithm is derived in the form of state feedback, whereas the required numbers of sensors are reduced by introducing an identification algorithm. Moreover, the implementation of the novel control scheme achieves the time-optimum response of a 3-D controlled variable in the LCL-type filter when damping the LC resonance strongly. The effectiveness of the proposed finite-time settling control algorithm is substantially confirmed by the simulation and experimental results of inverter, static synchronous compensator, and rectifier modes of operation.