Applied Mechanics and Materials Vols. 448-453

Abstract: A new control method, a model-free adaptive control,is used to resolve the steady-state error , insensitivity to the disturbance of power system, adaptive load is bad which is existed in feedforward control method of traditional, it only use the the data of load voltage and input voltage to determine the controller parameters, no need to establish the mathematical model of the system, Only by adjusting the parameters of a line, to achieve interference suppression system, the purpose of load voltage stability base on the theory analysis made emulation research and made the compare with the traditional feedforward control method . The Simulation results make clear that the correctness and feasibility of the method.

Abstract: The proportion of wind power in power systems is increasing year by year. Large-scale wind turbine off the grid when grid system failures. So the wind turbine needs to low voltage ride through (LVRT) function of wind turbine. Aiming at this problem, which in this article by DIgSILENT simulation software build 1.5MW doubly-fed wind turbine(DFIG) model, using active Crowbar and series grid side converter (SGSC) control strategy to realize the simulation of low voltage ride through of wind turbine. The control strategy of active Crowbar is mainly through the short circuit of rotor side converter to realize LVRT, and needs to be matched with the active and reactive power control strategy. SGSC is a novel converter structure, which mainly through compensating stator flux drop to realize LVRT. Finally this two kinds of control strategies were compared, demonstrated SGSC control strategy can achieve the low voltage ride through capabilities of the doubly-fed wind turbine.

Abstract: On the basis of analyzing the synthesis application of p-q (instantaneous reactive power) theory and unit vector template, a multi-functional grid-connected inverter (MFGCI) with auxiliary services on power quality enhancement in micro-grid (MG) is presented. The novel control strategy for achieving maximum benefits from these MFGCI when installed in AC MG access to 3-phase 4-wire distribution systems by isolated transformer at the point of common coupling (PCC). This kind of inverter can not only deliver the power generation of renewable energy sources (RESs), but also can perform as active power filter (APF) at their PCC as well as can improve the efficiency of inverter and decrease the hardware investment. Finally, both feasibility and effectiveness of this new topologies and control strategies of MFGCI are verified by PSCAD/EMTDC.

Abstract: the micro-arc oxidation technology is introduced in this paper firstly. The main circuit is designed according to the design demand. The main circuit is made up by chopper circuit and inverter circuit, the chopper circuit regulates the output voltage. Then the control circuit is designed, the control circuit include the key circuit, A/D converter circuit, driver circuit and LED display circuit.

Abstract: Permittivity signifies a key component to metamaterial which can achieve negative index of refraction, but it has not been sufficiently addressed in computational design. This paper aims to attain negative permittivity through a topology optimization approach and provides an example equivalent to electric inductive-capacitive resonator. Similar to split ring resonator, this locally self-contained (without the demand for inter-cell connection) resonator allows keeping bulk electromagnetic properties homogeneously, facilitating mass fabrication, and realizing single sampling test.

Abstract: Condensation heat of turbine exhaust steam is not only failed to use reasonable and effective in traditional thermal power plant, but also had a huge negative impact on the environment in the form of thermal pollution. This paper has a comparative analysis in condensation heat recovery technology programs of turbine exhaust steam, which is taken a certain 200MW CHP unit as the application object. Simulation and optimization analysis of the absorption heat pump technology is made for optimizing system parameters and operating parameters. The coal consumption analysis shows that absorption heat pump has a good energy conservation and emission reduction benefits.

Abstract: As a method in the evaluation of smart grid, anti-Shannon-entropy weight can compute index weight which is in even distribution or normal distribution, and a reasonable evaluation result can be obtained, but it is not fit for the weight computation when the index includes a distinctive event in non-unique small probability through the research. For the above problem, a novel index weight algorithmanti-nonextension-entropy weight algorithm is proposed and applied to evaluating microgrid. After constructing the typical microgrid evaluation indexes, some microgrids whose indexes include a distinctive event in non-unique small probability is taken as the research objects to find the difference of two evaluation methods based on the different anti-entropy weight algorithm, and the evaluation testing of microgrid is also performed using two methods. Theoretical analysis and simulation results show that in comparison with the traditional evaluation method the novel evaluation method can not only inherit the merits of the traditional evaluation method but also obtain the reasonable weight of index including a distinctive event in non-unique small probability, which improves the precision of microgrid evaluation.

Abstract: The concept of smart home is gaining in popularity. A new interactive terminal applied to smart home basing on Z-Wave is given. The interactive terminal includes control module, source module, level shift module, display module, Z-Wave communication module and peripheral circuit module, etc. The Z-Wave communication module is connected with control module in two-way mode, and communicates with smart meter, smart socket and intelligent switch. Also, Z-Wave communication module receives the tariff information from grid. Peripheral circuit module is connected with control module in single-way mode, and provides control module with clock information and protection. The installation of the terminal is simple and convenient. The terminal can be split easily, and also has the strong anti-interference ability.

Abstract: Due to their high inter-temporal variation and intermittence, large-scale integration of the new energies, such as wind power and photovoltaic power, will pose great challenges to the safe and stable operation of power system. Analysis on gird stability and adaptability before integrating the new energy should be made. The paper investigates all kinds of restrictions and assesses each constrained capacity from the perspective of steady-state and transient voltage, frequency stability, cross-section transmission limit and peak load regulating capacity, respectively. Then the comprehensive evaluation on the capability to accommodate new energy for a power grid is accomplished. Take a practical grid for example, its accommodation capacity for new energy is calculated based on the above-mentioned method, which provides a theoretical basis for the grid to accommodate new energy and planning and construction of new energy.

Abstract: The droop control is commonly used as the control strategy in microgrid. The traditional droop control only considers the relation between the active power and voltage frequency; and the relation between the reactive power and voltage amplitude.This study proposes the improved droop control ; which considers the active and reactive power are simulatedly related with both the voltage amplitude and the voltage frequency. This improved droop control not only could satisfy the load sharing in according to the capability of the distributed generations; but also represents better stability than the conditional droop control.The simulation in MATLAB/simuliink validate the effectiveness of the proposed control strategy