Advanced Materials Research Vols. 383-390

Abstract: This paper focuses on brushless doubly-fed generator (BDFG) control system used in variable speed constant frequency (VSCF) wind power generation. For maximum wind energy capture, a direct torque control (DTC) strategy is proposed based on the relationship between the maximum absorption power and speed of BDFG. The simulation results of the control system show that the maximum power can be tracked by a quick adjustment of the torque and the feasibility of the control system is verified using Matlab. Furthermore, considering the control system platform with DSP as the core, the control system software program and hardware circuit is designed, including main program and interrupt program processes.

Abstract: An AC-coupled output includes a series capacitor, while a DC-coupled output does not. This article explains the reasons for choosing either an AC-coupled or a DC-coupled video output. Maxim's DirectDrive video technology eliminates large output coupling capacitors and sets the output video black level near ground, which has the characteristics of an AC-coupled connection but the simplicity of a DC-coupled connection, is introduced. The working principle of Capacitive Charge Pump, is introduced too. Take the case of MAX9532 analyses the main choice of the components and parts in peripheral circuit, it has listed the precautions in the circuit design.

Abstract: Trilateral Flash Cycle (TFC) is particularly suitable for recovering energy from low-grade heat source. This paper presented a new mathematical model for calculating the performance of a twin screw expander integrated into a TFC working with organic components. The geometric parameters related to the rotation angle of male rotor e.g. groove volume, suction and discharge port area, leakage area etc were used in the model. The combination effects of internal leakage through five paths, oil injection, gas-oil heat transfer and refrigerant property were taken into account. The sensitivity of single parameter was also analyzed. To verify the model and the calculated p-φ indicator diagram, experimental recording of the diagram of twin screw expander was performed. The results of theoretical calculation were in good agreement with the experimental data, which indicated that the model in the present paper could be used as a powerful tool for performance prediction and product development.

Abstract: In the view of the shortcomings of high load fluctuation and complex operating parameters changes, the paper proposes a method, which combines the improved GM (1,1) Grey forecasting model and mathematical simulation for pumping operation, in order to simulate the operating parameters of oil field distribution network. By the metabolism ways of 4-days equal dimension and weighted average, these methods have improved the prediction accuracy. Based on the predicted results and the rand function in MATLAB, the operating parameters of oil field distribution network will be determined by power flow calculation. The example results show that the prediction accuracy and simulation results have achieved the expected goal.

Abstract: Based on the fusion of immune feedback mechanism for the conventional PID control technique, a new immune nonlinear PID controller is proposed in this paper. The stability of immune nonlinear PID is analysised using Popov stability criterion. The controller designed not only guarantees the stability robustness and performance robustness of the system but also the tracking performance of the system. The numerical simulation results of the Material-level control of the heat milling system show the effectiveness and feasibility of our immune unlinear PID are verified in Mat lab.

Abstract: Regenerative rotary reheating furnace is a new type furnace in metallurgy industry. It can reduce cost and it is low contamination exhaust. But it is hard for the temperature setting because it has complicated field and especial configuration. This paper focuses on the regenerative rotary furnace, develops mathematics models and regional discrete method for temperature setting. This paper produces a good example for subsequent research and development of regenerative rotary furnace.

Abstract: We conduct rapid and non-destructive experimental studies on various starches based on NIR and cluster analysis (a kind of quantitative analysis), taking a total of 54 samples from two starches as subjects, and study the feasibility of identifying starch categories with the combination of NIR and cluster analysis. The samples are identified quantitatively through cluster analysis (a kind of spectrum pattern recognition) under NIRDRS (near-infrared diffuse reflectance spectroscopy) with spectrum from 8914-1 to 4000-1 cm. Researches indicate that once the spectra are pre-processed trough vector normalization, samples can be classified into two categories accurately with cluster analysis, with a precision rate of 100%.In the meantime, the accuracy rate from experiment is also 100% when using the prediction set samples to test the accuracy of the model built. As research shows, a combination of NIRDRS and cluster analysis provides an accurate and reliable method to recognize starch categories rapidly and non-destructively.

Abstract: e furnace of steel plant is a complex controlled object and it has the properties of nonlinear, Time-varying and delay. Its modeling and control are very difficult. The temperature control of the furnace mainly depends on the control of gas flow. Therefore, the study of a reasonable gas flow control program is the key to increase the level of heating control. In this paper, an improved fuzzy PID control algorithm is proposed, in which, PID control algorithm and fuzzy control algorithm are integrated together, and its characteristics are improved according to feature of furnace. This made the algorithm to have good adaptability and Interference capability. The simulation results show that the improved control algorithm is better than traditional algorithm in overcoming the non-liner, delay of the object and the performance is excellent.

Abstract: This paper introduced a new technology of rapid prototyping which using wood powder as its raw material based on spray technology, and introduced working principle, and further elaborated the working principle and working process of the rapid prototyping methods, the system composition of powder supplied and powder paved, and the prospects of the rapid prototyping technology. This technology could solve the high-cost problem of rapid prototyping technology at present and had practical value in some degree.

Abstract: We focus on the annealing-induced changes of N-centered nearest-neighbor (NN) entironment in Ga1-xlnxNyAs1-y quaternary alloys and present a statistical distributing model of the binary bonds under thermodynamics equilibrium state. The core of this model is the assumption that the phase separation result of equimolar system at T=0 K is “ + ”, in which the effect of strain has been ignored. We propose two mechanisms for annealing: (i) Atomic relaxation lead to a total energy minimum. (ii) The type conversion of bond configuration is the main reason for the remarkable blue shift. Then parameter r, the number of NN In atoms per N atom, is calculated. We find that the theoretical NN distributions strain is in good agreement with former studies. It can be concluded that the blue shift induced by long-time annealing at low temperature is able to be equal with that induced by short-time annealing at higher temperature. The results are close to recent investigations. But an allegorical linear relation between band gap and composition (x, y) is still in question.