Dual Voltage-Current Control to Provide Grid-Forming Inverters With Current Limiting Capability

The rapid uptake of renewable energy sources is causing synchronous generators (SGs) to be replaced by power electronic inverters, meaning that these inverters need to offer the characteristics traditionally associated with SG. As a result, it has been proposed that the inverters should be controlled in a grid-forming mode in order to support the voltage of the microgrids. Given that these inverters are controlled as a voltage source, temporary events, such as short circuits or overloads, could cause currents that are far higher than the rated current. As the semiconductors used in power electronics are highly sensitive to overcurrents, this article proposes a dual voltage-current control that provides the grid-forming inverters with the capability to quickly limit the current under any overload or short-circuit condition. The proposed method has been validated through experimental tests in standalone mode.

Automated summary

The rapid uptake of renewable energy sources has led to the replacement of synchronous generators with power electronic inverters, which need to exhibit traditional synchronous generator characteristics. Therefore, it has been proposed to control the inverters in a grid-forming mode to support microgrid voltage. To protect power electronics from overcurrents, this article proposes a dual voltage-current control method that enables the grid-forming inverters to quickly limit the current under any overload or short-circuit condition.