Advanced Materials Research Vols. 383-390

Abstract: Short-channel under TaCN/La₂O₃ gate structure SOI NMOSFET has been studied in this paper, contrast with the traditional gate structure gate leakage current and others electrical properties, using TaCN/La₂O₃ gate structure，significantly improved short-channel device performance etc. Additionally, the gate structure in the L=40nm, 30nm and 20nm of C-V characteristic and output characteristic are also studied; all the simulation results coincide with the theoretical analysis.

Abstract: A novel flowrate sensor based on a couple of fiber Bragg gratings( FBGs) has been proposed, consisting of fiber grating pressure sensing setup and Venturi tube. The expression of relationship between the flowrate and the wavelength shift difference of the FBGs is derived. The pressure that two sides of the cross section of the aluminum foil tube in the pressure sensing setup results in the distortion of an isosceles triangle cantilever structure. The distortion results in the wavelength shift of a couple of FBGs that are mounted at either side of the cantilever. By monitoring the wavelength shift difference of the two FBGs, the flowrate can be obtained. The cross-sensitive problem of the FBGs sensor can be solved by compensating the temperature effect. The preliminary experiments have been carried out, and the results verify the feasibility of the proposed sensor with a measurement range from 8 to 200 mm/s.

Abstract: The user interface made of a LCD (liquid crystal display) screen and a touch screen based on LPC2138 is presented in this paper. The hardware design of the LCD and the touch screen is introduced and the software flow of the LCD and the touch screen is also described in this paper. And this paper proposes the synchronization algorithm which can achieve the LCD and the touch screen point by point with high accuracy and great reliability. On the basis of analyzing the principle of the embedded touch panel system, the working principle and control method of the dedicated controller DV320240GB touch screen are analyzed. The method for obtaining the coordinates of the touch screen and the synchronization algorithm of the LCD display are proposed to improve the efficiency of the touch screen and the LCD. The above-mentioned design has been successfully applied in ESR (erythrocyte sedimentation rate) detection system.

Abstract: The inverter technology gaining interest in high voltage high power is likely the multilevel inverter. The main characteristic of a multilevel inverter is able to reduce each power device voltage stress. Static Synchronous Compensator (StatCom) is the major application of the inverter to compensate reactive power in power system. Compared with traditional StatComs, multilevel StatComs exhibit faster dynamic response, smaller volume, lower cost, and higher ratings. A novel structure of StatCom with delta-connected multilevel inverter is proposed. The SPWM technique, which offers simplicity and good response, is used in the multilevel StatCom switching control strategy.

Abstract: Mineral grinding circuit (GC) is essentially multivariable system characterized with strong couplings, large time-varying parameters and multiple time delays. The product particle size and the circulating load are two important production indexes that directly related to the operation performances of subsequent beneficiation process. However, they are usually difficult to be controlled effectively with conventional control strategies due to the above mentioned complex characteristics. Especially the various process disturbances have a great influence on the control performances of the closed-loop system. In this paper, a multivariable disturbance observer (MDOB) based analytical non-interacting control (ANC) scheme is proposed to control the complex GC with model mismatches and strong external disturbances. Control studies have been performed by simulation tests for setpoint tracking, disturbance rejection and robustness problems.

Abstract: In this paper permanent magnet synchronous motor (PMSM) which is a multi-variable, nonlinear and high coupling system has a good performance adopting the strategy of field-oriented control (FOC) and space vector PWM (SVPWM). Furthermore, multi-PMSM synchronous driving system is established on employing adjacent cross-coupling strategy (ACC). In addition, a variable structure control with an integral sliding surface and exponential reaching law is designed for speed controller. Comparing with traditional PI controlled multi-PMSM system the results illustrate the effectiveness of the proposed control.

Abstract: Support vector machine (SVM) has excellent learning, classification ability and generalization ability, which uses structural risk minimization instead of traditional empirical risk minimization based on large sample. The perfect performance of SVM will be realized only if the parameters are rightly selected. The accuracy and efficiency of classification largely depend on the quality of the parameters selection. Focusing on the problem of the parameters selection in least squares support vector machine (LSSVM), a new method is proposed to optimize the parameters in LSSVM using adaptive genetic algorithm. The research is provided using this method on the fault diagnosis of a certain type of helicopter’s helicopter-electrical-box. Simulated results show that the proposed method achieves perfect accuracy and efficiency in fault diagnosis.

Abstract: In this paper, on the basis of the mathematic model of the three-level PWM rectifier, a power feedforward based control strategy is proposed combining with direct power control with space vector modulation (DPC-SVM) control principle. Feedforward control can reduce or even eliminate the impact on the system causing by load disturbance to improve dynamic performance. The simulation results show that the control method makes the system response speed faster and the dynamic performance better, it largely improved the system rectifier capacity against load disturbances.

Abstract: This paper presents a novel approach of single neuron PID control for switched reluctance motors based on RBF neural network on-line identification. The method is adjusted to the nonlinearity of switched reluctance motors, and use the single neurons capable of self-learning and self-adaption to form the single neuron adaptive controller of switched reluctance motors. It not only has simple structure and strong robustness, but but can adapt to environmental changes. Also we construct a RBF network system to identify the system online, and to build its online reference model, using a single neuron controller to achieve self-learning of its parameters, in order to achieve their online adjustment, and to obtain better control effect.

Abstract: Shaping and filtering of ultrashort pulsed beam at 1.06um by using multilayer volume holographic gratings (MVHGs) is analyzed. The modified multilayer coupled wave theory used to analyze the Bragg diffraction of a system of MVHG is derived. The spectral intensity distributions of the diffracted beam are calculated. The diffraction bandwidth, diffraction pulse duration and the total diffraction efficiency of the filter are also analyzed. Control of the optical pulse shape is accomplished by adjusting the width of the intermediate layer of an optical filter of MVHGs. This pulse shaping technique will be useful in the optical communication and optical computing systems.