This paper presents parallel operation of inverters grid-connected fuel cell systems in accordance with IEEE1547-2018 category3. The grid code regulations are becoming stricter due to the increasing amount of the new and renewable energy generated. Therefore, these new requirements need to be complied with. The current fuel cell system has its limitations to conform with IEEE1547-2018 category3. In order to solve this problem, a separate inverter is required, which is connected in parallel with the PCS of the fuel cell system. The inverter connected in parallel can be operated in two different modes. Constant current mode is applied when the grid is stable, while constant voltage mode applied when the grid is unstable. The control strategy for the parallelly connected inverter in fuel cell system is discussed and verified by simulation.
