Applied Mechanics and Materials Vols. 556-562

Abstract: The Smart Home is an important realization of the environments of intelligent electricity. As an essential part of the system, smart home smart sockets and the gateway work together to achieve the function of the on-off control, intelligent control, data acquisition and overload protection, etc. In this paper,the smart socker was designed and composed with the CC430 series processors introduced by TI , the power module, metering module and relay control module .At last, each module was tested accordingly.

Abstract: This paper mainly studies the off grid wind solar hybrid power supply system based on the DC bus, a practical mathematical model, implemented in MATLAB software on the system modeling and simulation. Through controlling the light intensity, temperature and other environmental parameters, operating characteristics of the system, analysis of system output voltage (current), dynamic and steady-state output power parameters. On the basis of the maximum power point tracking (MPPT) problem, and the maximum power point of PV power generation system tracking (MPPT) in-depth simulation experiments, using variable step perturbation and observation method, and the corresponding simulation model is established in MATLAB, changes in the environment variable parameters of the system can make timely adjustment re operation, in the vicinity of the maximum power point, and the work efficiency and the operating characteristics of the system through the analysis of the problem.

Abstract: The temperature distribution of the heat waveguide optical switch with different cladding materials is simulated on Fourier heat conduction theory and non-Fourier heat conduction theory, discussing effect of the cladding materials on the power consumption and the response speed of the device. The main conclusions as follows: (1)The response speed of waveguide optical switch with silica as cladding is faster than that with PMMA as cladding. (2)Thermal relaxation time has significant influence on the temperature of the core layer: the variation of optical switch core layer temperature gets bigger with the increase of material thermal relaxation time.

Abstract: To distinguish the ultraviolet (UV) photoresponse of Ohmic and Schottky contact devices, we have fabricated symmetrical and nonsymmetrical devices by standard lithography based on a single WO₃ nanowire. For the Ohmic contact device, the photocurrent can change from 100 nA to 300 nA. Even 200 s under UV illumination, nonsaturated photocurrent can be observed, and the fall time is more than 1000 s. But for the Schottky contact device, the rise and fall time are faster than that of Ohmic device. The barrier height of Schottky device can be easily controlled through the oxygen adsorption and desorption on the junction region, which can be served as a ‘‘gate’’ that effectively tunes the conductance of the device. Therefore, the Schottky barrier plays a very important role in the rapid-response of UV photodetector.

Abstract: Gas hot water boiler is widely used as heating equipment in everyday life. Because gas hot water boiler has the characteristics of nonlinear, large inertia and disturbances, so it is particularly important to build a precise mathematical model. Then the difference equation model of the system is identified by the least square method according to the collected data in this paper. Writing M file in the MATLAB software to get the continuous transfer function, and setting up Vague Set PID simulation, fuzzy self-tuning PID simulation and conventional PID algorithm in SIMULINK. By comparing among the three kinds of adjusting method, We get that Vague Set PID not only in regulation time, overshoot and effect of dynamic performance is superior compared the other two controller models , but also enhance the robustness and adaptability of the system, has a good dynamic, static performance..

Abstract: The diode uncontrolled rectifier or the phase controlled rectifier is widely used in conventional rectifier link, thus the conventional rectifier link on the grid inject a large number of harmonics and reactive power, and they cause a severe grid “pollution”. This paper starts from the basic principles of the PWM rectifier, then the paper discusses the topological classification of three-phase PWM rectifier in detail. Based on topological structure, the paper builds the mathematical model of three-phase stationary coordinate system and two-phase rotating coordinate system. Based on space voltage vector, the paper studies PWM control method in-depth and simulates in Matlab/Simulink. The correctness of the theoretical study of three-phase voltage source PWM rectifier system is verified by the simulation results.

Abstract: Vibration monitoring of machinery and equipment plays a very important role in judging the equipment maintenance and operational status. This paper discussed the mechanical vibration amplitude measurement system scheme based on PVDF piezoelectric sensors. The entire test system is mainly composed of PVDF piezoelectric film sensors, charge amplifiers, data acquisition and processing and display of valid values. It can display the amplitude of vibration signals in real time and alarm. The measurement system has the advantages of a simple structure and convenient operation.

Abstract: The unbalanced grid voltage causes the current harmonics, the fluctuation of the active power in AC side and the fluctuation of the DC voltage. The dual-current loops control strategy can slove those problems. The positive and negative sequence components of grid voltages and currents were calculated based on the symmetrical component method and were used to calculate the instantaneous power in double dq rotate coordinate, which ratate at positive and negative synchronous angular velocity respectively. The dual-current loops control strategy was finally verified in simulation by comparing with the conventional synchronous PI current control. The simulation results show the dual-current loops control strategy is effective on eliminating the fluctuation of the active power in AC side and the fluctuation of the DC voltage.

Abstract: Introduces the development of several power units of 24 multi-station pen machine, which include the contracting pipe power unit, the power unit of hitting three points, and the blanking power unit, analyzes the performance, structure and features of these power units.

Abstract: As an electric coupling sensor, the D-dot voltage sensor can achieve non contact measurement of voltage. With the advantages of simple structure, a high dynamic range and measurement bandwidth, it can meet the needs of accurate measurement^[1][2]. Thus it has great application prospects in voltage on-line monitoring, relay protection or other fields in the power system. This paper considered the operation of the three-phase lines, and established the D-dot voltage sensor simulation model in the simulation platform of Ansoft Maxwell 3D. With the simulation of the sensor working conditions, we can get the distributed parameters of the system under three-phase lines in operation, construct an equivalent circuit of measurement and analyze the simulation results to get a voltage signal of input and output. The simulation results show that, with the equivalent circuit simulation of the three-phase D-dot voltage sensor, if we improve electrode capacitance parameter, there will be a good linear relationship between the input and output.