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The objective of this research is to reduce the speed fluctuation of Permanent Magnet Synchronous Motor (PMSM) due to periodic torque fluctuation. To achieve this, the authors designed a cascade control system based on Linear/Nonlinear Switching Active Disturbance Rejection Control (SADRC) and Quasi Resonant Controller (QRC). Periodic torque pulsations, mainly the first, second, and fourth harmonics, are analyzed first. The architecture of the SADRC and QRC cascade control systems is then established. Subsequently, the parameters of SADRC and QRC are calibrated by the bandwidth method, and a closed-loop system model of cascade control is developed. Ultimately, periodic load fluctuations with step load fluctuations are applied at the load side to ascertain the efficacy of the SADRC and QRC cascade control systems. The SADRC and QRC cascade control reduce the first, second, and fourth harmonics of speed fluctuations by 74%, 33%, and 47.5%, respectively, through the use of QRC current compensation in the presence of peak 2 N m periodic torque fluctuations. The SADRC and QRC cascade control systems demonstrate excellent performance in the context of cyclic and step load fluctuations. [ABSTRACT FROM AUTHOR]

Data have become a virtual factor of production, and when integrated with the traditional factors of labor, capital, and land form digital labor, digital capital, and digital land, thereby generating a multiplier effect that contributes to the comprehensive revitalization of rural areas. This paper utilizes panel data from 30 provinces (autonomous regions and municipalities) in China from 2013 to 2023 and employs a double machine learning model to empirically test the impact mechanism of rural digitalization on the integration of rural industries. The results indicate that digital villages significantly promote the integrated development of rural industries through three direct pathways—digital industry development, digital information infrastructure, and digital service levels—with this conclusion remaining valid after a series of robustness tests. A mechanism analysis shows that digital villages facilitate the integration of rural industries through three indirect pathways—alleviating urban–rural factor mismatches, adjusting the agricultural–industrial structure, and promoting agricultural technological advancement—with this conclusion still valid after various robustness tests. The heterogeneity results show that there is significant variability in how digital villages promote the development of integrated rural industries, with the effects being more pronounced in major grain-producing and eastern regions compared to non-major grain-producing and central-western regions. Based on this, this paper proposes policy recommendations focused on accelerating digital village construction, formulating differentiated strategies, and alleviating factor mismatches, aiming to provide references for achieving rural revitalization. We mainly propose countermeasures and suggestions from three aspects: digital dividend, differentiation strategy, and element mismatch. Our main purpose in writing this article is to make up for the shortcomings of existing theories, enrich the theoretical system of digital rural construction, contribute Chinese solutions for digital rural construction around the world, and improve the word's level of digital rural construction. [ABSTRACT FROM AUTHOR]

The self-excited thermoacoustic instability (SETAI) frequently occurs in combustion equipment, leading to intense mechanical vibration, big noise and flame instability. SETAI poses a substantial challenge to the advancement of combustion technology, chiefly due to its complex mechanism. Our previous research has demonstrated that altering the premixed chamber length upstream of furnace can impact the interaction between heat release and sound pressure oscillations, which potentially enables SETAI control. However, supply duct is generally not straight, and changing the premixed section is impractical and unsafe. This paper aims to investigate the influence of introducing elbows and adjusting the supply duct length preceding the premixing stage on SETAI behavior. The goal is to offer guidance for the safe and convenient control of SETAI. Finds reveal that incorporating an elbow in the premixed chamber or changing its position does not affect sound wave propagation along the duct's center axis within a low frequency regime when maintaining a constant total equivalent length. In systems with both separate and premixed sections, the oscillation pattern is determined by the total time required for acoustic propagation throughout the entire supply system. Consequently, modifications to either of these lengths can impact SETAI. [ABSTRACT FROM AUTHOR]

Self‐excited thermoacoustic instability (SETAI) is a dangerous phenomenon in combustion equipment. While it is widely acknowledged that SETAI behavior is determined by the couple between pressure and heat release oscillation, their phase difference is difficult to predict, which impedes the development of SETAI control technology. With the aim of passive control technology development, this paper conducted experiment on a premixed hedge combustor to explore the mechanism whereby premixed chamber length (LP) and equivalence ratio (φ) collaboratively influence SETAI behavior. Results showed LP mainly affects the pressure mode shape within premixed chamber and consequently alters the phase difference between pressure and flowrate oscillation at combustion chamber inlet. Changing φ gives rise to different reaction time‐lag (τ), thus altering the phase difference between flowrate and reaction heat release oscillation. By introducing this flowrate oscillation, how LP and φ collaboratively determine phase difference between pressure oscillation and heat release oscillation was clarified. The mechanisms identified in this study are consistent with the emerging rationalization of the factors contributing to SETAI, and also provides better understanding on Rayleigh criterion and guidance for SETAI control. With further work on heat release and flow rate measurement, as well as the development on τ description, SETAI can be better predicted and controlled. [ABSTRACT FROM AUTHOR]