Extensive technique for grid‐connected converter power generation maximisation during asymmetrical grid voltages

Abstract

Short-circuit faults and asymmetrical power production and consumption result in the appearance of unbalanced voltages. The change in voltage profiles could result in grid-connected converter's overcurrent protection triggering if power references are kept at the pre-disturbance level. This study provides a framework for current references calculation that can result in virtually any active and reactive power profiles that are within the domain of the converter's physical capabilities. This is accomplished by introducing three references calculation algorithms, which are all based on the same underlying concept. The first algorithm gives the grid operator the option to choose to prioritise the production of either active or reactive power and to curtail the power production only to the extent that converter's current ratings are not surpassed. Simultaneously, the oscillations in one of the powers are managed. The second approach also provides power production prioritisation feature, but here power production is realised through adjustable ratio between positive and negative current components. The third scheme is an enhancement of the previous two schemes and allows for the constant power factor to be produced before and during the disturbances. Distribution network model emulated in the hardware-in-the-loop environment was used for the validation of proposed solutions.

Integrated Framework for Development, Emulation, and Testing of High-Level Converter Control Functions for Distributed Generation Sources

“…The analysis of simultaneous inverter currents quality enhancement together with power oscillations minimisation during unbalanced grid faults is shown in [20], [21]. Different prioritization strategies for active and reactive power generation desired by grid operators are given in [22]. The control scheme presented in Section 4 builds on the ideas proposed in these contributions.…”

“…For some voltage profiles, the mitigation of reactive power oscillations results in lower current amplitudes when compared with the regime in which only reactive power oscillations are controlled. For these voltage profiles it is advantageous to control the reactive power oscillations while the active power oscillations remain uncontrolled [22].…”

Guest Editorial: Challenges in Future Grid‐Interactive Power Converters: ControlStrategies, Optimal Operation, and Corrective Actions

“…To resolve power quality related issues in weak grids, paper [9] proposes an extensive technique for GCC power generation maximization during asymmetrical grid voltages. Paper [10] reports a control algorithm based on nonlinear adaptive second order Volterra filter to supply compensating current to improve power quality in weak grid condition.…”

Minimisation of power oscillations with a novel optimal control strategy for distributed generation inverter under grid faulty and harmonic networks

“…Mora et al [26] have proposed to eliminate the APOs and RPOs in four grid-connected converters. In [27], a new methodology based on current references calculation has been discussed to eliminate the power oscillations and to prevent overcurrent problems within the converter's physical capabilities.…”

“…Mora et al [26] have proposed to eliminate the APOs and RPOs in four grid‐connected converters. In [27], a new methodology based on current references calculation has been discussed to eliminate the power oscillations and to prevent overcurrent problems within the converter's physical capabilities. However, all these control schemes generally emphasise avoiding overcurrent problem, eliminating the APOs or the RPOs and improving reference tracking, while there is seldom control strategies considering the optimal selection model of the control coefficients to ensure minimal synthesis power oscillations.…”