Flexible Power Electronic Transformer for Power Flow Control Applications

This paper proposes a Flexible Power Electronic Transformer (FPET) for the application in the micro-grids. The low frequency transformer is usually used at the Point of Common Coupling (PCC) to connect the low voltage grid and utility network to each other. The conventional 50Hz transformer results in enhanced low voltage-grid power management system during grid-connected operation. In this paper, the whole system represented as two, three-phase AC systems with an intermediate high-frequency transformer for power flow controlling. The FPET consists of a high frequency transformer and three-phase to single-phase matrix converter. The matrix converters are modulated with a Pulse Width Modulation (PWM) strategy for a bi-directional power flow control. Phase shift modulation strategy in two sides of FPET is used for power flow controlling by PI controller from utility network to low voltage grid and vice versa. FPET model is established in Matlab/Simulink software with controller for power flow controlling. Presented simulation results have shown the validity of the proposed control system for FPET through the Matlab/Simulink simulation.