Bi-directional power flow through a digital grid router

Renewable energy sources have increased rapidly. The increase of renewable energy sources causes various problems. We propose a digital grid (DG) to solve these problems. The DG divides power systems when frequency is synchronized into various sizes. Each small grid is connected asynchronously with a digital grid router (DGR). The DGR is a multi-terminal AC/DC/AC power conversion device. In order to construct a DG, bi-directional power flow and asynchronous interconnection become the main factors. In this paper, we propose the control method of bi-directional power flow. We verify its possibility by doing an experiment. Through this method, we control the direction of current flow through a ‘leg’ and the value of current by hysteresis control. Hysteresis control is a method which controls the switching of an insulated gate bipolar transistor ‘IGBT’ by comparing output current and reference current having constant width of the amplitude of reference current. The direction of current flow can be changed whe...