LVRT capability enhancement of a grid connected three phase PV system by ADRC and DSOGI FLL

Abstract

Summary Low voltage ride‐through is considered as one of the key technologies for the operation of grid‐connected photovoltaic power generation systems. At present, the most used control methods are based mainly on PI controllers, and their robustness results are still unsatisfactory. In contrast, this article introduces a new robust control strategy that uses the compensation effect of “total disturbance” before affecting the system; this control strategy is called Active Disturbance Rejection Control (ADRC) method. In addition, most of the controllers use the standard SRF PLL to achieve the phase lock and grid synchronization. However, when the grid voltage is distorted or other unbalanced, it is necessary to use the positive sequence voltage component of the fundamental wave as a reference, but the component of the negative sequence cannot be effectively filtered because of its narrow bandwidth, and then, accurate phase lock cannot be achieved, which may cause a failure. In this purpose, a Double Second Order Generalized Integrator based Frequency Locked Loop (DSOGI‐FLL) is proposed and used to improve the system operating performance and non‐off‐line capability. In order to confirm the robustness of the proposed control strategies, a multiple simulations tests were done by utilizing the Matlab/Simulink software. The results have demonstrated the superiority of the proposed methods and their robustness to symmetrical and unsymmetrical faults.

Comparative Analysis between Proportional-Integral and Artificial Neural Network Control of a Grid-Connected PV System

“…To enable separate control of the grid's active and reactive power, Voltage Oriented Control (VOC) is employed. Specifically, 𝑉 𝑔𝑑 is set to 0 and 𝑉 𝑔𝑞 is set to 𝑉 𝑔 , which allows us to express the PV-System output (𝑃 𝑔 and 𝑄 𝑔 ) in the following manner [21,22]:…”

Active disturbance rejection control of an islanded PV/wind/battery microgrid with power quality enhancement by SAPF

“…The control circuit is given in Figure 6. For more details about the design of this controller please refer to our previous paper [32].…”

“…The active and reactive elements related to the fundamental frequency and the component related to harmonics. This results [37]: (32) To counteract the reactive power and harmonic currents generated by the nonlinear loads, the reference signal for the parallel active filter must encompass the reactive current and the harmonic current. Also, to compensate for the switching losses in the converter and to keep its DC bus voltage constant, the SAPF consumes a small amount of active power (𝑃 𝑑𝑐 ) that must be taken into account when generating the reference currents.…”

Fuzzy logic controller-based enhancement for grid-connected large-scale PV systems

“…This intricate transformation is rooted in the photovoltaic effect, a phenomenon by which exposure to sunlight instigates the generation of an electric current within these materials. The crucial mechanism behind this effect entails the utilization of photovoltaic cells, also known as solar cells, which are engineered to harness and exploit the interaction between photons and electrons [42][43][44][45][46][47]. Figure 1 shows a diagram of the PV systems.…”