Applied Mechanics and Materials Vols. 347-350

Abstract: With the increasingly serious crisis of the energy problem, all around the world, the application of solar energy has become an approach of solving the problem undoubtedly. In recent years, due to the rapid development of Chinese photovoltaic (PV) industry, the emergence of PV buildings is more and more widely in the domestic. The current trend is to apply Computer-Aided Design (CAD) software to realize the design of Building Integrated Photovoltaic (BIPV). The core problem of CAD is to obtain the best solution to a laying scheme of PV cell. In this paper, the design problem of PV building is concerned about. Through the research on the multi-objective optimization theory, it is to establish the model of multi-objective optimization that can meet these two objectives of the largest total annual solar photovoltaic power generation, yet the smallest possible the unit cost of power generation. The model can be solved by MATLAB using ideal point method. In order to detail explain the application of model and verify it, the design of PV cabin, in Datong area of Shanxi Province, is as an example. The study has laid the foundation for the development of CAD in the future.

Abstract: 1200V-8A 4H-SiC junction barrier schottky (JBS) diodes were designed and fabricated based on in-house SiC epitaxy and device technology. As a free-wheeling diode for the IGBT in inverter of motor system, the 1200V SiC JBS diode was compared to the Si ultra-fast diode from Fairchild Co. Ltd. The SiC diode achieved 88% recovery loss reduction and corresponding IGBT showed 35% lower turn-on loss. So, it will promote the application of motor system in high frequency and high efficiency.

Abstract: In this letter, a high breakdown voltage GaN HEMT device fabricated on semi-insulating self-standing GaN substrate is presented. High quality AlGaN/GaN epilayer was grown on self-standing GaN substrate by metal organic chemical vapor deposition. A 0.8μm gate length GaN HEMT device was fabricated with oxygen plasma treatment. By using oxygen plasma treatment, gate forward working voltage is increased, and a breakdown voltage of more than 170V is demonstrated. The measured maximum drain current of the device is larger than 700 mA/mm at 4V gate bias voltage. The maximum transconductance of the device is 162 mS/mm. In addition, high frequency performance of the GaN HEMT device is also obtained. The current gain cutoff frequency and power gain cutoff frequency are 19.7 GHz and 32.8 GHz, respectively. A high f_T-L_G product of 15.76 GHzμm indicating that homoepitaxy technology is helpful to improve the frequency performance of the device.

Abstract: With the rapid development of high-voltage large-capacity converters, multi-level inverter has been more widely used. Cascaded H-bridge multi-level inverter topology and using the trapezoidal modulation technique are described in this paper. The trapezoidal modulation of the H-bridge cascaded inverter is simulation studied with Matlab simulation software. This paper analyzes trapezoidal modulation techniques, how to establish the elimination of specific harmonics of nonlinear equations and the equations of Runge-Kutta algorithm to solve the problem, given in the different modulation to eliminate the 5th and 7th harmonic of the switching angle data. Finally, simulation results show the feasibility and correctness of the trapezoidal modulation of selective harmonic elimination technique.

Abstract: In multi-sensor integrated navigation systems, when sub-systems are non-linear and with Gaussian noise, the federated Kalman filter commonly used generates large error or even failure when estimating the global fusion state. This paper, taking JIDS/SINS/GPS integrated navigation system as example, proposes a federated particle filter technology to solve problems above. This technology, combining the particle filter with the federated Kalman filter, can be applied to non-linear non-Gaussian integrated system. It is proved effective in information fusion algorithm by simulated application, where the navigation information gets well fused.

Abstract: A design method of safety lock test based on 89S52 Singlechip is put forward and hardware structure and circuit scheme is introduced. Through the modularized design method of software, parameters of safety lock under different conditions are measured and quality test of safety lock is achieved.

Abstract: For the control characteristics of lithium batteries and nickel-metal hydride batteries, to design the hardware and software components of the PWM microcontroller battery charger, 2 battery charger can access, display temperature, automatic charging, sound and light alarm function. Voltage and current parameters self-tuning method to further improve the performance of adaptive charger, it can play a good dynamic response, fast charge and slow charge, the overshoot small, and has a the dynamic tracking quality and steady-state accuracy, and mobile phone lithium battery practical application, to obtain better control effects.

Abstract: Due to the impact from the conditioning circuit, it is easy to generate DC component for the reference voltage when the digital signal processor (DSP) sampling the grid voltage. It cannot eliminate the DC component for the grid inverter based on feed-forward decoupling control, and this would bring the DC component to the inverter voltage. The traditional DC component elimination method includes two aspects of hardware and software. This paper presents a new method to eliminate the DC component. The simulation results show that the algorithm is correct by using PSCAD/EMTDC.

Abstract: We study the Nth best relay selection schemes over independent and non-identically distributed (i.ni.d) Nakagami-m fading channels. For such opportunistic relaying schemes, we first obtain the closed-form expressions to the probability density function (PDF) and cumulative distribution function (CDF) of the instantaneous end-to-end signal-to-noise ratio (SNR). Then, with the obtained CDF and PDF, three main measurements are investigated, i.e., outage probability, average symbol error ratio (SER), and ergodic capacity. The numerical results show that the simulations match derivations exactly.

Abstract: The paper introduces the method by the way of applying Multisim in the course of the basic data electronic technique.We can find that the Multisim has a good perspective. Its ability of changing the circuit and component parameter can help us to know about its different characteristics of electronic circuit. It also will become a tool to train the students actual ability. To use the computers to design EDA will be a good direction in the course of electronic teaching.