Applied Mechanics and Materials Vols. 40-41

Abstract: This paper proposed a hierarchical structure model of the electronic system firstly, and then the expression method of the structure matrix was optimized. After that, the repair question of the system with redundant module was analyzed and turned into a kind of matrix solving, and the redundant repairs algorithm was provided at the same time. By repairing one bit half adder with one redundant mould, the feasibility of this method was proved and a new thought for the electronic system repair online was raised.

Abstract: To analyze the fault of AC circuit that contained several energy storage components, a method based on phase analysis is presented. Firstly, the circuit program is developed by MATLAB software, Equation of output voltage of AC circuit is established in MATLAB. Secondly, the program of phase analysis is compiled in MATLAB language, this program convert sinusoidal signal to phase signal. Thirdly, circuit responses are obtained in different fault conditions through repeated modifying parameters of components. Finally, fault dictionary is constructed that these samples will be used to diagnose AC circuit in the future. A fault analysis example of AC circuit is provided. The result shows that this method has several advantages of simple algorithm, objective formulation, understandable signal, explicit figure, etc.

Abstract: Based on the analysis of the design of USB peripheral driver program under embedded Linux and considering of the hardware characteristics of USB interface of the Portable WSNs Node Tester, the USB interface drive program for the Portable WSNs Node Tester based on the embedded Linux was designed by the way of kernel module. The WSNs Node connected the Tester through the USB interface, information transmission between the Tester and the WSNs Node was successfully realized.

Abstract: Wavelet denoising method is applied in the measurement voltage signals in this paper. Noise reduction is important for signal preprocessing in order to achieve many objects such as the improvement of accuracy of modal analysis and electrical parameter identification, the effective extraction of features and auto-matic classification of different kinds of signals. The voltage signals measured from one 35Kv bus are used for the preprocessing research. The denoising effect is evaluated by three parameters, i.e. signal to noise ratio, mean squared error, and capture ability of step points. Compared with the traditional methods including mean filtering and medial filtering, wavelet method is superior in signal to noise ratio and mean squared error.

Abstract: In recent years, there has been a growing interest in switched reluctance motor when it is widely used in the field of electric vehicles for its simple structure, low cost, high reliability, wide speed range, high response speed, high operating efficiency and strong renewable braking ability. The performance and structure of the power converter will directly affect the efficiency, cost and reliability of SRM, so the reasonable design of SRM power converter is the key to increase the cost performance of the whole SRM speed control system. Based on the principle and advantages of SRM, an improved asymmetrical half-bridge structure power converter with soft-switching is proposed for SRD in the paper. The DC / DC switching mode power supply for switched reluctance motor drive system is also successfully designed based on LT1247 integrated chip. Experiment results show that the new type of power converter and the DC / DC switching mode power supply can work better on electric vehicles.

Abstract: In this paper, a 34 to 36 GHz vector modulator for using in low cost and high performance RPC (Reflected Power Canceller) is presented. The key circuit consists of two push-pull (bi-phase) attenuators arranged in phase quadrature and a 3dB quadrature coupler (branch line couplers but not Lange couplers which is different from traditional circuits in Ka band) and a Wilkinson combiner, and then transition from micro-strip to waveguide using antipodal finline. To fully exploit this circuit’s capacity to generate accurate constellations at millimeter-wave frequencies, a generalized theoretical analysis of the (push-pull) vector modulator is presented. Based on the theoretical model and the measured results, the I-Q (push-pull) vector modulator promises to be a vital component for the realization of reflected power canceller in LFMCW (Linear Frequency Modulated Continuous Wave) radar.

Abstract: Based on technology of linear frequency modulation, constructed a wireless communication network in accord with the standard of IEEE 802.15.4a, which being fitted for using in mine. By method of symmetric double-sided two-way ranging, implemented a precise ranging and locating system for mines and tested it in indoor environment, which is similar to the straight laneway of mine and coalface. Result data show that the system has good performance in anti-jamming and anti-multi-path effects of electromagnetic wave and can communicate in a distance of 100m in laneway. The ranging accuracy is 1.5m, which well meeting the need of locating for person and equipment in mine.

Abstract: By circuit averaging method, a small-signal model is derived from push-pull forward topology which works in Continuous Conduction Mode (CCM). Dynamic large-signal model, DC circuit model and small-signal model are derived. The effect of leakage inductance on push-pull forward topology is analyzed and simulated in detail.

Abstract: In order to meet varied requirements of gas and electricity in petrochemical enterprises, as well as reducing the operation cost and minimizing energy use, optimal operation of steam power systems is a must. Based on previous work, this research proposes a mixed integral non-linear planning model (MILNP), which accounts for expenses of operation, maintenance, depreciation, and changeover cost in between startup and shutdown stage. The model is validated against operative data. The results show optimal control strategy can be quickly obtained with improved PSO algorithm, accompanied with considerable cost saving.

Abstract: Power sector faces serious challenges, e.g. greenhouse effect, acid rain, supply security, etc, along with the durative price rising of fossil and more worsening of environmental problems. An assessment model of power mix is put forward in this paper, basing on multi-criteria Diversity Analysis (MCDA). The efficient frontier can be gained at the basis of analyzing the power mix’s risk factors, such as environment pollution, supply security, system stability and land use. By the assessment model, the author analyzes the efficiency of China’s power mix in 2008 and 2020. We can find that actual China’s power mix is non-efficient, because of excessively depending on coal-fired plants. In order to decrease the risk of power mix, China should reduce the proportion of coal-fired plants, accordingly increase the proportion of clear energy, such as hydro, nuclear energy, wind energy, etc, in power mix. Hydro is the first choice for China to improve the efficiency of power mix. Nuclear is second at present. However, wind will become the second choice in future, if its cost can decrease because of scale effect.