Hybrid isochronous-droop control for power management in AC microgrids

The application of droop control as the sole mechanism for power management in microgrids is limited due to its difficulty in achieving operational economy and regulation of frequency. Consequentially, these needs are usually managed using higher level communication-based distributed or centralised control layers. To address these issues, this paper introduces an alternative approach for power management in AC microgrids, using a hybrid isochronous-droop (HID) control scheme that does not require communication. The proposed HID scheme is fully autonomous, and achieves a performance that is comparable with communication-based approaches. It enables generation sources to be scheduled in a defined priority, reduces the number of generation sources in operation for light load conditions, and improves the microgrid frequency load variation, all without requiring communication links. This enables efficient and reliable microgrid power management. Moreover, the proposed power management scheme is straightforward, easy to implement, and cost-effective, which are certainly features preferred by industry. The performance and robustness of the proposed scheme have been validated using an example microgrid operating under a variety of load conditions.