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Islanded mixed-source CERTS microgrids that include photovoltaic (PV) microsources and natural gas gensets are vulnerable to the collapse of the dc bus voltage in the CERTS-compatible PV microsources designed with voltage-source characteristics during dynamic overload conditions. Control techniques tailored to prevent the bus voltage collapse are explored. Simulation and experimental verification...
The modular multilevel converter (MMC) is attractive for medium-or high-power applications because of the advantages of its high modularity, availability, and high power quality. Reliability is one of the most important challenges for the MMC consisting of a large number of submodules (SMs). The capacitor monitoring in each SM of the MMC is an important issue, which would affect the performance of...
Traditional power systems have become outdated, unable to provide the clean energy enforced by current regulations. In addition, the intermittent renewable energy and the distributed generation make it difficult for the current electricity grid to reliably respond to increased energy demands. For that, a heat and power integrated energy system (IES) can provide better results compared to individually...
The internal model control (IMC) has been widely used for its simple structure, but its control performance has a relationship with the filter order and time constant directly, so that its disturbance rejection performance is influenced in the permanent magnet synchronous motor (PMSM) drive system. An IMC with extended state observer (ESO) is proposed in this paper. Based on the mechanism of IMC and...
A novel topology is proposed for three-phase electric spring (TPES) to achieve specific functionalities. With respect to the existing one, the novel topology contains an additional three-phase transformer with the primaries located at the position of the non-critical three-phase load (NCL) of the existing topology and its secondaries connected to the new three-phase NCL, thus forming a new three-phase...
The input capacitors' voltages are unbalanced under the conventional control strategy in a dual half-bridge cascaded three-level (TL) DC/DC converter, which would affect the high voltage stresses on the capacitors. This paper proposes a pulse-wide modulation (PWM) strategy with two working modes for the dual half-bridge cascaded TL DC/DC converter, which can realize the zero-voltage switching (ZVS)...
Developing a driving cycle in according with the actual road conditions is instrumental for the matching of power system design, fuel economy and emissions assessment. This paper used GPS to collect the actual operation of taxi in Harbin urban and divided into four model events: acceleration, deceleration, cruising and idle. The model events with similar mean of velocity and average acceleration are...
This paper proposes a new solution for realizing a pattern reconfigurable dielectric resonator antenna (DRA) using liquid injection to the 3D-printed container. The proposed methodology solves the existing problems of PIN-diode type reconfigurable antennas in narrow bandwidth and low radiation efficiency. The proposed DRA successfully demonstrates how to manipulate HEM01δ and TM01δ modes with broadside...
This study focused on the attitude of senior adults to text entry of Chinese characters on the mobile devices. Various Chinese input methods, including Pinyin input method, Wubi input method, Handwriting input method, Stylus input method, Voice input method, other input methods, were evaluated in this study. Preference and Motivation on different text entry methods were investigated. This study interviewed...
Cyber-Physical System is a novel intelligent system integrating computing and physical procedures, which combines computing, communication and control technologies. Event is the key element to link the cyber world and the physical world. However, the time stamp of the event is imprecise in practical applications because of data loss, mismatching of the time granularities of events from different monitoring...
Spectrum sensing is the fundamental technology of Cognitive Radio (CR). This paper proposes a novel multiple-antenna based spectrum sensing method with random arrivals of primary users (PUs). The method first constructs a local test statistic for each antenna based on the assumption that the PU is randomly arriving, and then calculates the estimated optimum coefficient for every local test statistic...
While visible light positioning (VLP) cooperated with mobile platform has been considered as one of the most attractive solutions for indoor positioning mobile services, most existing visible light positioning (VLP) systems have limited performance in terms of positioning accuracy and speed due to the requirement of multiple VLP luminaires for vision analysis and the high computational cost of image...
Two kinds of side-polished fiber (SPF) devices with ordered/disordered polymer nanostructure cladding were demonstrated. The nanostructure cladding was constructed by the dehydrated dichromate gelatin(DCG). The temperature sensitivity of the device with disordered polymer nanostructure cladding was up to 1.360 nm/°C, which was 70 times larger than that of the device with ordered polymer nanostructure...
Violet light sensing of a micro fiber (MF) with cladding of titanium dioxide (TiO2) nanoparticles on the tapered region is demonstrated. The device has a sensitivity of ∼0.28 dB/mW (1520 nm), which indicates that the TiO2 holds g reat potential in photonic applications such as fiber-optic sensors or controlled Devices.
Physical-layer security is desirable for visible light communication (VLC) in order to hide information from unauthorized receivers, without reliance on upper-layer encryption. In this paper, we propose a physical-layer secure coding scheme based on polar codes to achieve secrecy capacity of indoor VLC under Wyner's wiretap model. Compared with the beamforming approach requiring multiple-input, single-output...
Software watermarking is a general tool usedto combat software piracy by embedding identifying informationinto a program. Most existing schemes of softwarewatermarking have the weak point that the security onlydepends on the stealth of the watermark structure. Besides,the watermarking is independent of program in semantic leveland can be destroyed via fairly straightforward semanticspreservingcode...
In this paper, a numerical model of halloysite nano-tubes (HNTs) modified surface plasmon resonance sensor is established and optimized. The simulations investigate the effect of HNTs size parameters on the SPR sensor performance. From this study we can find that the optimal design for halloysite modified SPR sensor.
In this paper, we demonstrate and investigate numerically the chiral coupling effect between a microfiber and a nanofiber. The light propagation direction in the nanofiber is determined by the handedness of the light field in microfiber. According to the radius of nanofiber, the fundamental mode in microfiber can be coupled into both the fundamental and the higher order modes of nanofiber. Our findings...
This paper proposes a frequency scanning-based impedance analysis for stability assessment of grid-connected inverter system, which is able to perform stability assessment without using system mathematical models and inherit the superior feature of impedance-based stability criterion with consideration of the inverter nonlinearities. Small current disturbance is injected into grid-connected inverter...
We propose an improved image defogging algorithm based on Retinex, which consists of two parts: HSV color enhancement and RGB space detail enhancement. Through the single-scale Retinex algorithm to enhance the brightness component, in HSV space to introduce enhanced adjustment factor, to avoid color distortion and noise amplification, to achieve the effect of color enhancement. In the RGB space, based...
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