Chongwei Zhang

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—In order to realize the Smart Grid vision, it is necessary to have guaranteed Quality of Service (QoS) for the communication and networking technology used in various stages of the Smart Grid, ranging from power generation, transmission, distribution, to the customer applications. The low cost wireless protocols such as Zigbee (using IEEE 802.15.4 defined(More)
In high power wind power generation systems, grid connected voltage source inverters (VSI) are essential devices for power transporting and energy converting. Output currents of inverters increase harmonic distortion due to low switching frequencies. A series inductance usually is used to reduce switching harmonics entering the power distribution network.(More)
The localization is an important issue in wireless sensor networks(WSN). As one of the range-free localization algorithms, DV-Hop can be simply implemented in real WSN. To improve the accuracy of localization, three improved algorithms are proposed based on the characteristic of DV-Hop with the first one based on secondary reference node, the second one(More)
The starting control of AMT vehicle clutches is complicated with multi-influence factors, multi-parameters and multi-objectives. By selecting various control parameters at different stages of the clutch jointing, a fuzzy control method was adopted to resolve the complexity and the uncertainty. Also, control matching between the clutch and the engine was(More)
The transient coupling between the vessel motion and liquid sloshing in multiple tanks is investigated. External disturbance factors (e.g., spring constraint or force field) that might affect the oscillation characters of the coupling system are not involved so that the vessel motion is only excited by the liquid sloshing in tanks. The analytical solution(More)
A third-order KdV solution to the internal solitary wave is derived by a new method based on the weakly nonlinear assumptions in a rigid-lid two-layer system. The solution corrects an error by Mirie and Su (1984). A two-dimensional numerical wave tank has been established with the help of the open source CFD library OpenFOAM and the third-party software(More)
Filtration during extracorporeal circulation (ECC) not only removes but also activates leukocytes; therefore, long-term leukocyte filtration may cause adverse effects. In the present study, we tested this hypothesis by priming ECC with 300 mL of canine blood and examining filtration effects in 3 groups (n = 6 each) during 60 min ECC. In the control group(More)
Based on the characteristics of DV-Distance, an improved algorithm for wireless sensor networks is proposed. The main principle of the improved algorithm is introducing of the straight line/polyline ratio of and the hops between the anchors, reducing the cumulated distance error and location precision error. The simulation results show that the improved(More)
Permanent magnet synchronous Generator (PMSG) based direct-drive WECS has been attracting wide attentions. For the special application, sensorless control for PMSG is desired. By widely studying the previous contributes, a novel estimator based on back-EMF is proposed. The estimator is composed of back-EMF observer and a phase-lock-loop (PLL) control to get(More)