Advanced Materials Research Vols. 433-440

Abstract: This paper studies on how to design a new kind of permanent magnet synchronous motor according to the need of electric wheel. We broaden the limits from the power density and moment of inertia, and focus on security, speed control range, start torque, overload capacity and so on. By linking mechanism, the motor is connected to wheels and drive them directly. The motor and the wheel hub also remain relatively independent. So the motor inherits the advantage of electric wheel and broadens the limits from dimension at the same time.

Abstract: ZIGBEE and LONWORKS related technologies are the current research focus in the area of the communication, and it plays a great part in the development of the intelligent building. At the same time, how to collect the power parameter accurately is in urgent need in the intelligent building. We take the CC2430 of the TI Corporation as the host processor, the Neuron 3150 of the Echelon Corporation as the coprocessor to build the communication system, and use the ATT7022 chip to collect power parameters, so we can control and monitor the power through this communication system.

Abstract: In this paper, an efficient algorithm for computing 10-point DFT, radix-10 FFT algorithm for computing 10^M-point DFT and N=L×10^M-point DFT are presented. FFT is often employed in power systems harmonics analysis even though it is not accurate due to spectral leakage and barrier effect. When N=L×10^M-point DFTs are used to analyze harmonics in power systems, comparing to N=2^M-point DFTs, very accurate harmonic parameters can be obtained. The simulation results in MATLAB show that the methods are feasible and effective to enhance analysis accuracy.

Abstract: This paper set up the model of power transmissive observational section and put forward the real-time tracking method of power angle curve in steady state which could be used to identify and focus on monitoring the weak links, then to take early warnings of low frequency oscillation. On the dynamic situation of system been disturbed, we extracted the real-time dynamic damping value of the observational section, calculated its fitting curve of local maximum points and took the slope of curve as the criteria, in order to achieve early warning of low frequency oscillation under multiple disturbances in the interconnected power system.

Abstract: Electronic instrument transformers are used in power line for electrical measurement and protection purposes. Calibration instruments are necessary for the transformation error test of electronic instrument transformers. The operation principles of the direct and difference measurement method based calibration instrument for the medium-voltage electronic instrument transformers are systematically analyzed in this paper. The analysis results show that the direct measurement method based instrument can be used for the calibration of electronic instrument transformers with air-core coils or resistor-capacitor voltage divider without a built-in integrator, and the difference measurement method based instrument is suitable for the calibration of the electronic instrument transformers with no rated phase offset.

Abstract: Support Vector Machines (SVM) has been extensively studied and has shown remarkable success in many applications. However the success of SVM is very limited when it is applied to the problem of learning from imbalanced datasets in which negative instances heavily outnumber the positive instances (e.g. in medical diagnosis and detecting credit card fraud). In this paper, we propose the fuzzy asymmetric algorithm to augment SVMs to deal with imbalanced training-data problems, called FASVM, which is based on fuzzy memberships, combined with different error costs (DEC) algorithm. We compare the performance of our algorithm against these two algorithms, along with different error costs and regular SVM and show that our algorithm outperforms all of them.

Abstract: As a new microwave remote sensing technique, synthetic aperture interferometry has been developed rapidly in last thirty years. It is based on synthetic aperture. The imaging algorithm of the synthetic aperture radar interferometry (INSAR) is introduced. Two approaches of flat earth removal are derived and compared. The influence of the flat earth removal processing to the interformetry phase statistics distribution and phase derivative is analyzed. The results indicate that the flat earth removal technology makes the phase unwrapping easier and improves the precision of it.

Abstract: This paper introduces digital substation engineering applications typically schemes of CBZ-8000B in different stages of the program, in which the analog input uses the mode from the IEC61850-9-1 point-to-point to the IEC61850-9-2 network transmission, 10kV analog inputs use the IEC60044-8 small analog mode, and it realizes the transmission of tripping and closing commands and network protection by transporting GOOSE information of process layer. Meanwhile, superior points of different projects are compared and the greater innovation and application on network protection and quadratic functions which will be achieved in following engineering application are forecasted.

Abstract: The unfragile control problem of a class of uncertain state-delay sampled system is discussed. Applying Lyapunov method, and combining the properties of matrix inequality, the sufficient condition of robust stability is given, and the unfragile controller is designed. Finally a numerical example illustrates the effectiveness and the availability for the design.

Abstract: The eddy current loss of stator strands in the in-phase slot and out-phase slot was calculated by the finite element method (FEM). 3D static heat transfer equations and equivalent variation equations of large turbo-generator under the Cartesian coordinates system were given. The stator temperature field of large turbo-generator was calculated by using 3D FEM, and the influence of thermal conductivity reduced due to main insulation aging both in in-phase slot and out-phase slot on the stator was analyzed. The obtained conclusions will provide theoretical basis for fault prediction and fault diagnosis.