A vector control strategy to eliminate active power oscillations in four-leg grid-connected converters under unbalanced voltages
Fecha
2020-06
Tipo
artículo original
Autores
Mora Castro, Andrés Felipe
Cárdenas Dobson, Jesús Roberto Pedro Alejandro
Urrutia O., Matías
Espinoza Bolaños, Mauricio
Díaz Díaz, Matías
Título de la revista
ISSN de la revista
Título del volumen
Editor
Resumen
The problems associated with active power oscillations (APOs) in grid-connected converters are well-known. Imbalances in the grid usually produce double-frequency oscillations in the dc-link voltage and current which could reduce the useful life of solar panels, batteries, and capacitors connected to this point. Moreover, as reported in the literature, double-frequency
reactive power oscillations (RPOs) also produce adverse effects
in distribution systems, and it is desirable to eliminate or
mitigate them. When a four-leg power converter is connected
to an unbalanced grid, the zero-sequence current provides
extra degrees of freedom to compensate or even eliminate the
power oscillations at the converter dc-link side. In this paper,
a new methodology to regulate these double-frequency power
components is proposed. It is based on a closed-loop vector
control approach, where the active power oscillations (APOs)
at converter side are transformed into a synchronous frame
rotating at twice the grid frequency and regulated using the
zero-sequence current. To avoid overcurrent produced by the
circulation of positive-, negative-, and zero-sequence components a current limiter is also proposed in this paper. Experimental results obtained with a 4-kW four-leg power converter prototype are presented and discussed in this paper.
Descripción
Palabras clave
DC–AC converters, distribution system, symmetrical components, Reactive power, DC-AC power converters, Power distribution, Power control