When several UPSs are connected in parallel, individual UPS should take charge of exactly same load current Because the output impedance of each UPSs is very low, small voltage difference among them will give rise to circulating current will bring a...
When several UPSs are connected in parallel, individual UPS should take charge of exactly same load current Because the output impedance of each UPSs is very low, small voltage difference among them will give rise to circulating current will bring about the decrease of UPS own capacity.<br/>
In order to solve this problem in this paper an inverter controller for the UPS which has a good response characteristic and robustness for directly applying in industrial world is proposed. This paper also describes that difference between load current divided by number of operating inverters and its own current is detected as unbalanced current Then frequency and voltage are controlled to minimize the active component and the reactive component respectively. A good controller load-sharing technique is verified by experiments in the parallel poerating system with 40kVA UPSs.