@inproceedings{5828dfda901544a89a86948ec08d44e6,
title = "Control of parallel single-phase inverters in a low-head pico-hydro off-grid network",
abstract = "In rural locations, where the national power grid is not available, pico hydropower (<;5kW) is typically used in stand-alone configurations, with one unit supplying a single house or a small community. This paper investigates the interconnection of several off-grid pico-hydro generation units with differing power ratings and unequal distances from the load. Each unit is identical, employing a single-phase power electronic converter interface, which comprises a rectifier, a DC-DC converter, and a single-phase inverter. There is no communication between the units, each unit using local measurements to control its output with the ability to form and support an off-grid network. The inverter regulates the output voltage and frequency using droop control. The output impedance is fixed using a virtual resistance, decoupling the droop equations. The voltage control loop has addition harmonic loops to improve voltage quality. The droop coefficients and virtual resistance are adjusted according to the power available at the turbine to ensure that the power sharing is proportional to the available turbine power. Experimental results show that the harmonic voltage control loops improve the voltage quality significantly, with the total harmonic distortion reducing from 9.53% to 1.93% when a non-linear load is connected to a single inverter. The transient response of two parallel inverters to the switching in of a non-linear load, and the response of the power sharing ratio to the hydraulic head at one turbine unit being reduced are demonstrated and shown to be stable.",
keywords = "rural electrification, Off-grid network, droop control, parallel inverter, pico-hydro",
author = "Williamson, {Sam J} and Antonio Griffo and Stark, {Bernard H} and Booker, {Julian D}",
year = "2014",
month = mar,
doi = "10.1109/IECON.2013.6699367",
language = "English",
isbn = "9781479902255",
series = "Proceedings of the IEEE Industrial Electronics Society (IECON)",
publisher = "Institute of Electrical and Electronics Engineers (IEEE)",
pages = "1571--1576",
booktitle = "IECON 2013 - 39th Annual Conference of the IEEE Industrial Electronics Society",
address = "United States",
note = "39th Annual Conference of the IEEE Industrial Electronics Society, IECON 2013 ; Conference date: 10-11-2013 Through 14-11-2013",
}
