On Grid-Interactive Smart Inverters: Features and Advancements

Traditionally, a grid-interactive inverter providing ancillary services is called a smart inverter. However, broader features will be required for the next generation of inverters that can be categorized as self-governing, self-adapting, self-security, and self-healing. For grid-interactive inverters, the self-governing feature can be identified as the capability of inverters to operate in grid-following and grid-forming control modes, where the self-adapting is referred to as more flexibility realized by adaptive controllers for stable dynamics of inverters under various grid conditions. Moreover, for supervisory control and economic dispatch in a grid with high-penetration of inverter-based power generators, a minimum communication might be necessary, but it can place grid-interactive inverters in danger of being hacked when self-security becomes essential to identify malicious setpoints. Furthermore, the self-healing is defined as fault-tolerance and stress reduction under abnormal conditions. It suggests that after realizing these features, an inverter is called a smart inverter. In this paper, the advancements toward achieving these features for grid-interactive inverters are reviewed.