Short-Circuit Current Limiting Control Strategy for Single-Phase Inverter Based on Adaptive Reference Feedforward and Third Harmonic Elimination

The fast short-circuit fault ride-through capability of the inverter is an important indicator for the reliability of an independent power supply system. Fast short-circuit fault ride-through requires the inverter to output the short-circuit fault current quickly and reliably, which is conducive to shortening the duration of short-circuit faults and realizing fast short-circuit protection. In addition, when the single-phase inverter outputs a short-circuit fault current, the third harmonic in the short-circuit current may cause malfunction of the protection circuit. To effectively achieve the fast short-circuit current limiting and third harmonic suppression of the single-phase inverter, this article proposes a short-circuit fault diagnosis strategy and a current-limiting control strategy, respectively. The former is a short-circuit fault diagnosis strategy, and the latter is a fast current limiting control strategy based on adaptive reference feedforward and third harmonic elimination. The proposed strategies can enable the single-phase inverter to reach a current-limiting steady state within a fundamental period, which can greatly improve the response speed of single-phase inverters and achieve fast short-circuit protection. They can also be applied to three-phase inverters. A 35-kVA/50-Hz high-power single-phase inverter prototype is built to verify the effectiveness of the proposed method.