Multivariable Grid-Forming Converters with Direct States Control

A multi-input multi-output based grid-forming (MIMO-GFM) converter has been\nproposed using multivariable feedback control, which has been proven as a\nsuperior and robust system using low-order controllers. However, the original\nMIMO-GFM control is easily affected by the high-frequency components especially\nfor the converter without inner cascaded voltage and current loops and when it\nis connected into a strong grid. This paper proposes an improved MIMO-GFM\ncontrol method, where the frequency and internal voltage are chosen as state\nvariables to be controlled directly. In this way, the impact of high-frequency\ncomponents is eliminated without increasing the complexity of the control\nsystem. The H-infinity synthesis is used to tune the parameters to obtain an\noptimized performance. Experimental results verify the effectiveness of the\nproposed method.\n