## 1 Introduction  
WPS are the fastest growing renewable energy sources from the perspective of cost and that of benefits. There are many benefits to using a permanent magnet synchronous generator (PMSG) as opposed to the DFIG; PMSGs and DFIGs are the two most popular systems used in WPS operation. A PMSG has several advantageous features, such as the absence of a gearbox, high power density, and a simple control mechanism with high precision; however, its cost is greater than that of a DFIG because it uses permanent magnets and needs topologically full power converters [1, 2]. As many power electronics-based converters require intricate control mechanism driven by complex strategies, this full power converter is beneficial in terms of WP control [3, 4]. Initially, a WPS is required only to operate at the maximum power point tracking (MPPT) to produce as much power as possible at a given wind speed using model-based or model-free methods [5]. Even though the WP experiences fluctuations and uncertainties in its power production, they had no significant impact on grid stability because their proportions were relatively low when compared to the total power produced by the grid. However, when many WPSs are integrated into a power network, these fluctuations and uncertainties can result in a significant impact on the operation of the grid [6, 7]. Therefore, grid operators require WPSs to support stable grid operation by setting up a grid code. One of the major issues in developing a grid code for WP is the low-voltage ride through (LVRT). Using an LVRT grid code for WPSs, a grid can recover from a low voltage grid fault and achieve stable operation immediately after the occurrence of the fault [8]. Recently, the universal grid code was introduced in Reference [9] after taking into consideration the entire set of LVRT requirements of all countries. We considered the most extreme requirement from this set to validate the effectiveness of the proposed method. Grid code requirements vary depending on the power system. Each grid code defines the specific duration for which a wind turbine (WT) should remain connected during the fault period; this duration depends on the voltage sag level [8]. Thus, the grid code is related to power system characteristics and should be varied according to the WP penetration level. As shown in Figure 1, different countries have different requirements regarding the LVRT connection time; this parameter also takes into consideration the zero voltage condition. Various methods have been proposed in the past for LVRT control. These methods can be categorized into two groups. One group is characterized by the WT alone handling the LVRT while the other group uses additional devices such as FACT, energy storage system (ESS), or other energy dissipating devices [10]. A PI current controller for dc link voltage regulation using current feed-forward methods was proposed for better transient response; further, the impact of unbalanced voltage sags on the controller performance was studied [11]. A feedback linearization controller was proposed in Reference [12] for nonlinear control of the GSC in a PMSG. Using this controller, the performance of the GSC current control strategy during a voltage sag was improved by maintaining its rate of current flow within a given range. Because this method is quite complex to implement, feedback linearization was implemented using a sliding mode control [13]. A sliding mode control algorithm was applied in the GSC control scheme to regulate the dc link voltage [14]. This results in a better performance compared to that obtained using a linear control strategy as dc link voltage dynamics are nonlinear and the GSC exhibits this nonlinearity in its switching operation. [15] proposed a combined control for pitch and RSC control. The authors also used a breaking resistor to ensure that the WPS did not reach the current limit or rotor speed limit during LVRT.