Power control for grid-connected converter to comply with safety operation limits during grid faults

This paper presents a new power control strategy of grid-connected converter under grid fault conditions. Positive-and negative-sequence reactive power are controlled separately in order to effectively support unbalanced grid voltage. Both maximum phase current limit and maximum active power oscillation limit are taken into consideration which makes the converter operate safely under grid faults. Spare capacity are fully used to generate active power. Reactive power is generated immediately and active power is generate gradually during calculation procedure which makes it possible for online application. Also, generating active power gradually lighten the burden of crowbar or other energy transfer devices and bring less impacts to grid. Experiment results prove that the proposed method is effective.