Decentralized Controller for a Grid Tied Cascade Multilevel Inverter

The article is about a decentralized controller for a Cascade Multilevel Inverter connected to the grid. The objective of this controller is to supply current to the grid and to balance the output voltage of each full bridge cell. The controller is composed of two stages, one to manage the output current and the other for balancing the output voltage of each Full Bridge cell. Besides, a bypass system is implemented in the controller in order to have the ability to insert or remove a full bridge during the operation. This control technique avoids that the disturbances in the current affect the voltage balancing of full bridges. The control technique is validated in three simulations, changing the output current reference, disturbing the input voltages and inserting/removing a Full Bridge cell. Finally, the article shows the comparison between theoretical part and the simulations.