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Flexible multi-state switch (FMSS) has the characteristics of nonlinearity and strong coupling. It is difficult to achieve complete decoupling of output power through traditional proportional integral (PI)control. There are some problems in PI control such as difficulty in adjusting PI parameters, slow system dynamic response speed, and poor robustness. Firstly, feedback accurate linearization is uesd to transform the FMSS from a high-order nonlinear system into two completely independent first-order linear systems, realizing the complete decoupling of active and reactive currents. Then, aiming at the problems of slow approach speed, poor system convergence performance and large motion chattering of traditional sliding mode control, an improved sliding mode control based on adaptive approach rate is designed to optimize the voltage outer loop and the current inner loop, and the stability of the proposed algorithm is verified by Lyapunov function. Finally, the simulation analysis of the three-port FMSS are carried out in the Simulink software under the conditions of output power disturbance, AC voltage sag and system parameter perturbation. The results show that the proposed control enhances the robustness and anti-interference ability of the system, and it can effectively increase the dynamic response speed of the system.

Ceramic/polymer nanocomposites have been extensively explored for dielectric capacitor application due to their high energy storage performance and ease of processing, flexibility, and low cost. However, improving compatibility between inorganic and organic materials is of great significance and has been a long-standing challenge. In this work, the polymer surfactant Pluronic[TM] F127 was employed to perform surface modification of Ba[TiO.sub.3] through a facile solution process. The compatibility between Ba[TiO.sub.3] nanoparticles and P (VDF-HFP) can be remarkably strengthened by the affinity between F127 polymer chains and the organic matrix. Structural defects such as pores, cracks, and agglomeration of inorganic particles were obviously reduced, and interfacial polarization has been significantly enhanced. The discharged energy density [U.sub.d] and charge-discharge efficiency [eta] reach up to 5.0J/[cm.sup.3] and 58.1% under the breakdown strength of 3740 kV/cm for the nanocomposite containing 1 vol% BT@F127. These dielectric properties are clearly better than the nanocomposite using unmodified BT, as well as similar hybrids reported previously. KEYWORDS ceramic/polymer nanocomposite, dielectric property, energy density, surface modification, 1 | INTRODUCTION Dielectric capacitors are the basic components of energy storage in modem electronic and electrical systems. They have been widely used in the fields of power transmission, hybrid [...]

The rapid development of 5G and 6G technologies has led to an increased demand for microwave dielectrics ceramics. Microwave dielectrics ceramics with high Q value and low cost have attracted a lot of attention from researchers. Such as material sintered at relatively low temperature and cheap raw materials. Magnesium titanate (MgTiO3) is a material with excellent dielectric properties but requires high-temperature sintering. It is reported that substitution of Zn2+ for Mg2+ can lower sintering temperature and improve dielectric properties. Here, microwave dielectric properties and phase evolution of Zn-excess Mg0.95Zn0.05+xTiO3+x (x = 0, 0.025, 0.05, 0.075, 0.1) compositions were investigated. A moderate Zn-excess is found to promote formation of pure MgTiO3 phase with lower temperature. The composition with x = 0.05 sintered at 1300 °C possess optimal dielectric performance εr of 17.85, Q × f of 173,300 GHz (@11 GHz) and τf of − 52.04 ppm/°C with relative density of 97%. [ABSTRACT FROM AUTHOR]

Calcium bismuth niobate (CBN) ceramic, as a core element of high-temperature piezoelectric sensors, has attracted widespread attention due to its high Curie temperature within the class of Aurivillius compounds. However, CBN usually faces two shortcomings: poor piezoelectric constant and low resistivity. In this work, CBN-based ceramics with donor–acceptor ions (W/Co) co-substituted at B-site were prepared by solid-state reaction method, and structure–property relationship of ceramics was studied in detail. Co-substitution of W/Co ions effectively improved the electrical property and hardness of CBN ceramics. CaBi2Nb 1. 9 1 (W 2 / 3 Co 1 / 3 ) 0. 0 9 O9 exhibits enhanced electrical and mechanical properties including high resistivity of ∼ 1 0 7 Ω ⋅ cm at 500°C, piezoelectric constant of ∼ 1 5. 3 pC/N and hardness value of ∼ 3. 5 7 GPa. These values are two orders of magnitude, over two times, and 1.36 times higher than those of pure CBN ceramic, respectively. This work provides a reference for exploring other bismuth-layered structural ceramics. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the impact of the Kovar glass content on the mechanical and electrical properties of Si3N4–Kovar composites sintering at air atmosphere. To achieve this, Si3N4–Kovar composites were prepared using molding technology with the Kovar glass powder ranging from 20 to 70 wt%. The phase composition, morphology, bulk density, apparent porosity, flexural strength at room temperature, dielectric constant, and dielectric loss of the composites were all examined in relation to changing the Kovar glass content. During the sintering process, the α‐quartz on the surface of Si3N4 particles acted as the crystal nucleus, inducing the crystallization of the glass at the wetting position that the Kovar glass and the surface of the Si3N4 particles. A small amount of the β‐quartz phase was crystallized at 750–850°C, followed by a large amount of the β‐quartz phase crystallizing above 900°C. Additionally, some β‐quartz phase transformed into the metastable β‐cristobalite phase that could exist below 1470°C. During the cooling process, the β‐cristobalite phase transformed into a low‐temperature α‐cristobalite phase, while the β‐quartz phase transformed into a low‐temperature α‐quartz phase. The results indicate that the Si3N4–Kovar glass composite with 60 wt% the Kovar glass content sintered at 900°C exhibits higher density (1.88 g/cm3), lower porosity (25.4%), higher flexural strength (55.34 MPa), lower dielectric constant (3.46), and lower dielectric loss (4.26 × 10−3). [ABSTRACT FROM AUTHOR]

Starting from the market rules of the pilot provinces of the domestic spot market, this paper analyzes the mechanism of market intervention and suspension, the mechanism of the power supply period, and the mechanism of market clearing anomaly. At the same time, combined with the real-time operation of the Inner Mongolia power grid, the traditional dispatching mode and the power spot market operation dispatching mode are compared. Given the abnormal frequency, section overload, and insufficient spinning reserve in real-time operation, an auxiliary decision mechanism of manual intervention in the power spot market is proposed. The mechanism includes load bias setting, section limit bias setting, deviation monitoring, and other auxiliary functions, which provide a method of quick intervention under the electric spot market to ensure the safe and stable operation of the power grid.