System interconnection power conversion device

Abstract

A voltage drop Vzs is calculated based on an output current detection value Iac and a virtual synchronous impedance Zs or a corrected virtual synchronous impedance Zs’, and a value obtained by subtracting the voltage drop Vzs from an internal induced voltage Ef is output as a grid voltage command value Vac*. Zs calculation unit 7 limits an output current phase Ɵ so that the output current phase Ɵ is within an effective range by a phase limiter 12a, and calculates the corrected virtual synchronous impedance Zs’ based on a limited output current phase Ɵ, the internal induced voltage Ef, a grid voltage detection value Vac and a current limit value Ilim. Accordingly, in grid interconnection power conversion device that controls a virtual synchronous generator, it is possible to continue operation while suppressing an overcurrent and possess a synchronizing power generated by action or working of a virtual synchronous impedance.