Mobile QR Code QR CODE : The Korean Institute of Power Electronics
Title An Output Voltage Balance Control of Grid Connected Inverter by Phase Current Control at Critical Load Unbalanced Condition
Authors Tae-Hyeon Park ; Hag-Wone Kim ; Kwan-Yuhl Cho ; Joon-Ki Min ; Won-Il Choi
Page pp.22-29
ISSN 1229-2214
Keywords Grid connected inverter; Stand-alone mode; Balanced phase voltage control; Critical load unbalaced; Load unbalanced control
Abstract A grid-connected inverter can be used in grid-connected or stand-alone modes. Generally, a grid-connected inverter operates in a grid-connected mode, but the inverter operates in stand-alone mode if grid faults occur. In the stand-alone mode, the grid-connected inverter must supply electric power to a critical load that needs to receive stable power even though grid faults occur. Generally, three-phase loads are used as critical loads, but a single phase is configured in some cases. In these conditions, the critical load is required to unbalance the load power consumption, which makes the three-phase load voltage unbalancd. This unbalanced voltage problem can cause fatal problems to the three-phase critical loads, and thus must be addressed. Hence, this paper proposes an algorithm to solve this unbalanced voltage problem by the individual phase current control. The proposed method is verified using Psim simulation and experiments.