Advanced Materials Research Vols. 986-987

Abstract: The reactive compensation controller using MC9S08AW60 chip and ATT7022A is introduced. The detail design of the hardware and software is illustrated too.

Abstract: This paper proposes a design method of the micro power consumption synchronous chopped wave and low-power switching power supply based on fixed and mobile double comparative point. The output of this power supply ranges from 5V to 200V. It overcomes the residual voltage effect after the bridge rectifier by using fixed comparative point to limit the maximum output voltage, and stabilizes the voltage by using mobile point to produce the required output voltage. The circuit charges with nonlinear resistors pattern in the low voltage, thus improving the charging efficiency, and it has short circuit protection function, simple structure and low power consumption.

Abstract: Half bridge switching power supply is a kind of form in the family. It has the characteristics of good voltage output, high efficiency, the simple circuit and so on. On the design of the half bridge switching power supply, the key and difficult point is the design of switch transformer. Taking the switch transformer of a half bridge switching power supply as the research object and based on the design requirements, this paper aims to realize the calculation of the coil turns and the selection of core in switching transformer. the design of switch transformer of the push-pull switch power supply has been completed by circuit simulation and implementation.

Abstract: Compared with the normal energy meters which use the integrated measurement chip as the key component, the three-phase reference energy meter based on FPGA and ARM possesses the advantages of high precision. And compared with the energy meters which use DSP as the key part, it has the advantages of small volume and multi-parameter measurement. The design method of three-phase reference energy meter integrating FPGA with ARM is presented in this paper. And the individual miniaturization design are discussed, the key parts during the realization are also discussed. After that, two kinds of electric energy metrological algorithm which are digital differential and instantaneous IV are introduced according to the characteristic of the system, and the advantages and disadvantages of them are compared. All this work will provide powerful foundation for the engineering applications of design method.

Abstract: In view of the problems that traditional direct current control calculation is complex, that sensor precision requirements are high. This paper proposes a new control method of unit power factor power converter, which is easy to realize with simple control structure dispense with current sensor. Through the simulation and experimental verification, the control strategy can achieve unity power factor control, and the harmonic content is small and the operation is stable.

Abstract: China's coal mine monitoring system and scientific management level is relatively backward. Environmental information of coal mine is difficult to achieve control and sharing. Combining with the traditional model of the safe production of coal, the author presents a new monitoring system structure of coal mine based on embedded technology to achieve the aboveground control and underground monitoring of coal mine. By combining control instance of monitoring system, this paper focuses on the safety production monitoring system design and implementation of coal mine, and describes the design methods for monitoring system, which is helpful for China's coal production safety.

Abstract: Cross-linked polyethylene cables are widely used in power transmission system. In this work the effect of frequency and boost on the breakdown performance of XLPE cable with inserted needle defects was investigated by the frequency-tund resonant system with frequency ranging from 20Hz to 300Hz. The breakdown paths were observed by an optical microscope, and the fractal dimensions of the paths were estimated according to box-counting method. It was found that, with the increase of frequency, the variation of path fractal dimension as a function of frequency corresponded to that of breakdown voltage. Compared with the continuous boost method, the frequency, at which the fractal dimension of breakdown paths approached saturation and the breakdown voltage peaked, became lower under step test method. The increase of breakdown voltage is due to the increase of electrical power used for the initiation and development of dense discharge paths.

Abstract: Three-phase combined transformer has a large number of application to special energy metering in power grid, its performance is directly related to the accuracy of electric energy metering. So it is necessary to ensure its performance and accuracy. It rules that three-phase combined transformer should be calibrated with three-phase method, but most of metrology departments calibrate three-phase combined transformer in single-phase method. Based on the mechanism of the three-phase transformer, single-phase method and three-phase method had been compared on three-phase transformer experimental platform. The result shows that it would be large error when the three-phase transformers are calibrated with single-phase method. Three-phase transformer calibration should be operated with three-phase method.

Abstract: Whereas three-phase phase locked loop could not get accurate phase position under three-phase unbalanced condition of the power grid, the design of single phase locked loop is implemented in the principle of single phase locked loop, based on FPGA technology. the paper explains design difficulties of single phase locked loop in detail, puts forward adaptive sampling scheme using single phase locked loop under variable frequency, increases accuracy of SVC sampling system. And tests response speed of phase locked loop via Real Time Digital Simulator for Power Systems (RTDS), through final verification in Fushun Lishizhai SVC Project, the design could meet system requirement for voltage phase accuracy.

Abstract: The paper presents sixteen nullor-mirror representations for the reported grounded gyrator by means of sixteen alternative NAME equations of the gyrator. Moreover, only four alternative grounded gyrators employing OTAs have been received. Having used canonic number of components, the circuits are easy to be integrated and their parameters can be tuned electronically through tuning bias currents of OTAs. The MULTISIM simulation results have been included to verify the theoretical predictions.