Applied Mechanics and Materials Vols. 556-562

Abstract: This paper proposes a high-power LED driver circuit with economical high power factor based on universal chip NCP1200. NCP1200 itself doesn’t have the function of APFC, however, by adding a simple amplitude control circuit in the periphery without using special dedicated APFC chip, the APFC rectification mode can be achieved at work, which greatly reduce the pulse current caused by first-time rectification, the power factor can be as high as 98%, and it can achieve the goal of constant current drive in the meantime. The designed circuit is simple, low cost, stable and reliable work ability and it has high cost performance.

Abstract: The AC electronic load circuit is studied, PWM converter is used in this circuit in order to achieve the simulation function of load characteristics.The methods of how to get the command current mathematical model and simulation module is given which is based of the Matlab/Simulink platform, Hysteresis control mode is used in order to get fast and stable actual current and then carried on the simulation of the proposed electronic load. The simulation results show that the proposed algorithm and the control instruction current method and the effectiveness of the current control method, realized the simulation of ac electronic load.

Abstract: The operating status of the microgrid is given, currently three classic control modes of microgrid isintroduced. And a method is put forward, which is a improved active power-frequency droop control method based on Lagrange interpolation.This method can effectively guarantee the stability of the microgrid running frequency. The correctness of the method is confirmed through the simulation.

Abstract: In order to solve the problem of electricity from the grid, designing a set of independent power supply system based on micro-network technology, through the use of solar, wind, diesel, battery, etc. This paper introduces the structure and working principle of the system, focuses on the design of the control system to meet under no circumstances, intelligent control of the entire system to make it stable operation, and optimization method proposed system configuration.

Abstract: The advantage of HVDC is large power of transmission, low cost and good control performance. Generation system has harmonic because of the nonlinear characteristics of the converter. It has very important significance for HVDC transmission system to accurate analysis and rational allocation of harmonic filtering device. This paper mainly studies the characteristics and suppression of harmonics on AC side in HVDC system, and the filtering effect of different filter combinations of simulation.

Abstract: The development and application of energy storage technology was described. Based on wind power fluctuation limit and system peaking demand in the smart grid, a novel optimized operation strategy between wind power and energy storage devices. The correctness of the strategy is verified by numerical example.

Abstract: A new optimum design process is established by mathematical model in this paper based on the theory of material mechanics and electricity. According to optimization,the conductive ring device is designed. Based on virtual modeling under abaqus, the simulation validation of experimental design is carried out.contact resistance is calculated under contact states. A series of data measured in simulation shows that this final optimum design of conductive ring has a better performance than the experimental design in physical properties.

Abstract: This paper introduced the research status of microgrid control system(MCS) and analyzed the functions of microgrid control center(MCC). A design of multi-functional of microgrid control center was presented , and each relevant functional module was described.

Abstract: FPGA structures are common designed in Serial structure and Parallel structure. As the most efficient one, Parallel structure also could be divided into whole-parallel and half-parallel which we called pipe-line structure. Whole Parallel structure FPGA take a great advantage on speed but consuming enormous resources. Moreover, FFT cannot give enough details on Time-frequency domain. In order to avoid these disadvantages, proposed STFT processer plan on FPGA. Based on the research on algorithms STFT, we gave an improved pipeline structure FPGA design. Then this design implied high speed STFT which take both speed and precision into count on FPGA. At the last of this paper, we conducted signal test. In this step , any signals were all collected from actual work condition. And then verify the feasibility of the program through simulation and actual signal test.

Abstract: This paper presents a capacitive humidity sensor in CMOS technology. The humidity sensor element is implemented in standard CMOS technology without any further post-processing, which results in low fabrication cost. The sensor interface is based on a delta-sigma converter and can be easily reconfigured to compensate for process variation of the sensing element. The proposed humidity sensor is fabricated in 0.16μm standard CMOS process and the chip occupies 0.25mm². The measurement result shows that this humidity sensor acquires a resolution of 0.1%RH in the range of 20%RH to 90%RH. The interface achieves a 12.5-bits capacitance-to-digital conversion and consumes only 9.6μW power at 1.2V supply voltage.