The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
An effective way to solve the problem of wind power curtailment is to install heat storage (HS) facilities in CHP plants. However, the existing power grid does not have the ability to schedule the heat storage facilities. In this paper, we have developed the combined heat and power dispatching system to schedule the power plants as well as the heat storage facilities for the maximum effect of wind...
In this paper, a near Optimum Power Allocation (OPA) for a cooperative jamming relay network is proposed, by using physical layer security to protect the user's messages from relay's interception. The network uses Amplify and Forward (AF) relay to enlarge the coverage area, however the relay is untrusted. By defining secure Energy Efficiency (EE) as the ratio of the instantaneous secrecy rate to the...
The output voltage of a traditional full-bridge inverter is lower than the input dc voltage. In applications when the input voltage is low, the front-end step-up converter is usually required, presenting a two-stage power conversion. Dual boost inverter (DBI) can realize single-stage conversion, which has the advantages of a simple structure, less power devices, and buck–boost ability. The traditional...
Modular multilevel converter (MMC) has been proved a prospective topology in high voltage and high power occasions. Hybrid MMC mixed with half-bridge (HB) and full-bridge submodules (FBSMs), which achieves a good tradeoff between power devices quantity and dc short circuit fault handling capability, attracts extensive attention. In this paper, the characteristics of SM capacitor voltage ripples are...
For medium- to high-voltage AC/AC conversion applications, direct AC/AC conversion scheme by adopting the modular multilevel converter (MMC) shows remarkable advantages on costs and efficiency compared with the AC/DC/AC solution which employs a back-to-back MMC configuration. However, direct AC/AC MMC suffers from branch energy instability when conversion frequencies of input and output are equal...
Security is a demanding request for wireless networks, with physical layer security the problems in traditional encryption algorithms and key management are vanished. In this paper, a novel beamforming scheme is proposed to improve secrecy rate in an untrusted relay network, where the untrusted relay helps to improve the network coverage area but may act as a potential eavesdroper. A destination-assisted-jamming...
Modular multilevel converter (MMC) has attracted great attention in the high voltage direct current (HVDC) transmission systems. Redundant submodules (SMs) are usually set to enhance the reliability of MMC. However, if some SMs break down, the arm energy is unbalanced and fundamental fluctuation appears in the DC current. This paper proposes an arm energy rebalancing control scheme to suppress the...
Hybrid transmission systems associated with line commutated converters (LLC) and voltage source converters (VSC) have gradually become a particular solution for high voltage direct current (HVDC) transmission. The full-bridge submodule (FBSM) based modular multilevel converter (FB-MMC) has gained significant attention for its dc voltage reversal and fault ride through capabilities. However, large...
Because the numerous nonlinear components and fiber interfaces are used in Module Multiple Converter (MMC), the HIL test of MMC with detailed EMT model and the full-scale interface is hard to be implemented. In recent years, this existing disadvantage caused the MMC controller hardware and software difference between the HIL test and real project. In this paper, a detailed EMT model of hybrid MMC...
Unwanted residual vibration in dynamic system always causes many problems in industrial manufacturing. For instance, it is difficult for a crane to transport a heavy cargo to a specified location safely, quickly and accurately in the case of oscillation. In this paper, the crane system is simplified as a rail trolley hoisting system where the payload is a rod, and an input shaping method is investigated...
A fault-alarm based hybrid controller design approach for Markovian jump system with actuator fault is investigated in this paper. By using linear matrix inequality (LMI) technology, both robust and reliable controllers are presented, which ensure that the normal systems and the fault systems are robustly stable. Then, in order to reduce the conservativeness of reliable controller design algorithm,...
For medium- to high-voltage, high-power direct AC/AC conversion, modular multilevel converter (MMC) is a potential solution due to its outstanding features. However, MMC suffers from branch energy instability when frequencies of input and output are equal. This paper presents a single-phase five- branch MMC which is capable of direct AC/AC equal frequency conversion without branch energy stability...
In this work, a hybrid plasmonic microfiber knot resonator (HPMKR) is demonstrated as well as its multi-sense applications. A microfiber knot resonator (MKR) is attached to gold film and generates the hybrid plasmonic mode. The HPMKR has an extinction ratio of more than 10 dB in C-band, with the Q-factor of more than 47,000. For a chosen polarization, the resonator has an extinction ratio of nearly...
Here we report an active microresonator by integrating a thin layer of all-inorganic CsPbBr3 nanocrystals (NCs) to a silica microsphere. We also demonstrate the transition from spontaneous emission to stimulated emission (SE) of CsPbBr3 with varying pump power. Further lasing is expected by improving the fabrication technology. Our configuration may provide a route to low threshold and compact lasers,...
The applications of specklegram analysis techniques have been developed recently. In this paper, we represent a fiber-optic method to measure the temperature through the analysis of output specklegrams. The proposed all-fiber device excites higher-order modes through splicing a multimode fiber (MMF) to a single-mode fiber (SMF) with a core offset. The basic principle of the sensor is based on determining...
We proposed a portable online Raman detection system with all fiber components, by inserting two large-diameter optical fibers respectively into each end of the inner metal-coated capillary for Raman excitation and signal collection simultaneously. The all fiber structure not only could enhance the interaction length between the excitation beam and the detecting material, but also provide a very effective...
We demonstrate a new fiber-optic current sensor based on graphene nanoelectromechanical systems (NEMS) with a graphene membrane covering the hole on a fiber tip and two gold electrodes on opposite sides of the tip. The suspended graphene membrane will deform due to thermal effect when electrical current flows through it. Then the strain in the graphene nanomechanical resonator will change and it leads...
In this paper, we fabricate a microfiber coupler (MFC) functionalized with Teflon thin film. Since Teflon has a negative thermo-optic coefficient, it can compensate for the thermal effects of silica. The temperature dependence of the MFC depends on the radius of microfiber which controls the thermal effect contributions of silica and polymer. The device we fabricate has the temperature sensitivity...
There will be a big load on the structure after aircraft ditching and spacecraft water recycling, which has an important effect on the safety of the capsule structure and the people inside. Therefore the research of water impact has a practical significance. Base on the wedge and arc body model, the test of the body free falling on the water has been vertically investigated. The acceleration signals...
The state feedback control switching problems for stochastic fuzzy system by means of switching technology are discussed in paper. The sufficient conditions for mean square stability via linear matrix inequality (LMI) are introduced by using the multiple Lyapunov function methods. The state feedback switching controllers are designed, and these controllers are switched at the point of state feedback...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.