Design of the fuzzy PI control system for load voltage in hybrid distribution transformer.

Hybrid distribution transformer (HDT) is a novel transformer that has a powerful control on grid current and load voltage, and it is significant for the construction of the smart grid. The load voltage control is the key part in HDT control system. Here, a load voltage control strategy based on fuzzy PI controller is proposed, since the traditional PI controller cannot achieve satisfying dynamic performance under the operation of grid voltage change. The fuzzy controller can respond faster than PI controller for the outputs that is only determined by inputs and independent with time, when the grid voltage rags or swells. While combining the fuzzy controller with the PI controller, the fuzzy control will cover the shortage of PI control in transient process and the PI control ensures that the static performance will not be affected. In the end, the simulation model of HDT is carried out, and the result shows that the load voltage can track the reference faster than the traditional PI controller, which improves the performance of voltage control system. [ABSTRACT FROM AUTHOR]