###### Abstract
In recent years, the research of battery Energy storage technology, especially large capacity battery energy storage, has been changing with each passing day, the control technology has been continuously improved and innovated, and the cost of energy storage has been constantly reduced. The application of battery energy storage in the field of wind power control will usher in greater opportunities. The causes of low-frequency oscillation include rapid changes in wind speed, tower mechanical oscillation, and control dynamic interaction, etc., which can be analyzed based on external monitoring or internal modeling, using negative damping, bifurcation theory, etc. From the perspective of the power grid, the weakly damped LFO is often derived from the dynamic interaction between the internal controls of the SGs. The grid-connected DFIG and SG control strategies interact with each other, which may aggravate the low-frequency oscillation. Installing SGs a power system stabilizer (PSS), improving the PSS control strategy and control parameters, and adding wide-area control to high-voltage DC, flexible AC, energy storage and other equipment, can also suppress LFO. The difficulty lies in the control algorithm and coordinating with each other. The basic idea of suppressing LFO is to increase system damping, including adding PSS to SG, optimizing control parameters of DFIG [5], adding POD to DFIG, and adding flexible AC transmission systems (FACTS) and high-voltage DC(HVDC) with POD, etc. [6]. In the frequency regulation task of the power grid, the synchronous machine has a slow response but still bears the main role of frequency regulation. The rapid response of the inverter can provide short-term support and a conservative bottom line. The two need to work together and jointly for frequency regulation. This article focuses on the research of wind turbine inverters and energy storage inverters. The imbalance of active power is the inherent driving force behind low-frequency oscillation in the power grid, so inverters must provide active support to suppress the fluctuation of active power in the power grid system, thereby quelling low-frequency oscillation in the power grid [7]. This article first takes the wind storage joint grid connection system as the research object and establishes a wind storage system model; secondly, it analyzes the suppression strategies of wind storage systems for low-frequency oscillations. The main contribution is the installation of POD on the side of the Double-fed Induction Generator machine side converter and the installation of POD on the energy storage side converter, and adjusting the frequency based on the frequency trajectory planning method. Finally, a simulation model is built in Matlab/Simulink 2019 simulation software to verify the effectiveness of the proposed suppression strategy through simulation. The paper is structured as follows: the modeling and analysis of wind storage systems are presented in Section 2, the control strategy for suppressing low-frequency oscillation in wind storage systems is discussed in Section 3, and in Section 4 the Pareto-based controller parameter optimization is presented. In Section 5, the simulation verification and conclusions are presented.