Model-free Subspace-based Control Scheme for Grid-Connected Voltage Source Inverters

In this paper, both model-free subspace-based LQG control and H-infinity control schemes are used to investigate the tracking control performance and robustness of grid-connected voltage source inverters (VSIs). The proposed approaches do not require any identification or other modeling process. The controller can be directly derived from the experimental inputs/outputs measurements. Both the subspace-based LQG controller and H-infinity controller are recursively designed. Simulation results show subspace-based LQG controller has a better tracking control performance than subspace-based H-infinity controller, whereas, H-infinity controller has stronger robustness than LQG controller.