Secondary Frequency Control of Isolated Microgrid Based on LADRC

Abstract

The microgrid is considered to have bright prospects in the future for its advantages of high economic benefits and environmentally friendly and alleviate the antinomy for energy's supply and demand. Due to the introduction of renewable energy such as wind power into the microgrid, the intermittent, random, and unpredictability of its output makes it difficult to control the frequency when the microgrid operates in the isolated islands. In order to reduce the frequency fluctuation, this paper proposes a secondary frequency control strategy for isolated microgrid based on the linear active disturbance rejection control (LADRC) technology. Extended state observer (ESO) is used to estimate the extended state online and compensate the disturbance estimation actively so that the disturbance can be eliminated quickly and the frequency stability can be maintained. In addition, considering the demand response, the influence of different demand response coefficients on frequency control is analyzed. By a series of trial declarations, the LADRC control strategy can effectively suppress the frequency oscillation, and after adding the demand responses, the response speed can be faster than the traditional frequency modulation, reflecting its better robustness and stability. The simulation based on the frequency response model of AC microgrid results shows the effectiveness of the proposed method. INDEX TERMS Renewable energy, islanding microgrid, LADRC, demand response, ESO.

Load Frequency Control of Pumped Storage Power Station Based on LADRC

“…LADRC is composed of three important components: linear extended state observer (LESO), linear feedback control law, and disturbance compensation. Figure 4 shows the second-order LADRC structure adopted from [26], where r and y are the reference input and output of the system; G p (s) is the controlled object; k P and k d are the linear feedback control rate parameters; d is the external disturbance of the system; and b 0 is the estimation of the input gain b of the system in the controller. The principle and function of each structure are introduced below.…”

“…The controller adopts traditional PID, FOPID, and LADRC. According to the parameter design of the controllers in [26], the cut-and-trial method is used to determine and select the LFC parameters suitable for the pumped storage power station in this paper, so as to effectively suppress the disturbance and restore the frequency stability. Its control parameters are given in Table 2, and the simulation time domain is 60 s. The frequency variation chart of the disturbance zone under different controllers is shown in Figure 6.…”

Analysis and Control of Fault Ride-Through Capability Improvement for Wind Energy Conversion System Using Linear Active Disturbance Rejection Control With Correction Link

“…Sinceḟ is unknown and can be estimated by correction,ḟ is omitted. Rewrite the observer equation [32], [36], as follows:…”

“…According to the structure of LADRC-CL shown in Figure 6 and results of combining the model information (29)- (36), the structure of the LADRC-CL with model information can be obtained, as shown in figure 11.…”

A Novel Hybridized Fuzzy PI-LADRC Based Improved Frequency Regulation for Restructured Power System Integrating Renewable Energy and Electric Vehicles

“…Sahaj Saxena et al have investigated internal model control for AGC of a single and multiple area system in the presence of uncertainty [17]. LADRC is proposed for the frequency regulation of microgrid in [18].…”