Advanced Materials Research Vols. 846-847

Abstract: The imbalanced neutral point potential issue of the NPC inverter is analyzed in this paper. Based on the redundant voltage space vector control algorithm, a novel strategy by adjusting the working situation of positive and negative small vectors is proposed, which can suppress the neutral point potential imbalances effectively. The method is simulated with SIMULINK, and the control algorithm is implemented with the DSP of TMS3202812 in the laboratory. The simulation and experiments showed that the strategy is effective.

Abstract: A modified equivalent circuit model of an acoustic gas sensor with resonator is introduced in this paper. Based on FMYB and Babak models, our modified RCL-link model simulates the impedance curve in terms of amplitude and resonant frequency well. This modeling would be a helpful step to the gas mixture measurement and analysis.

Abstract: By analysing the wafer, the electrodes, etc. according to the energy limit theory and the ANSYS finite element simulation, in this paper the author has designed the integrated quartz crystal resonator and oscillator circuit, and has carried on the experimental comparison on the stability of the integrated resonators, which have different structure, different electrode material and thickness. The experimental results show that the frequency stability of quartz crystal resonator is not only related with the electrode material and thickness, but also related with the structure. Under the same condition, resonator of asymmetric structure has better frequency stability, and the stability of Au-electrode was better than others, and its magnitude could reach 10 ¹⁰. With the increase of the electrode thickness, the resonator oscillator stability will be improved.

Abstract: A staring and nothing blind-zone video surveillance system was designed based on the DSP chip of TMS320DM6467 and the fish-eye lens which has ultra-view field. This fisheye lens has 185 degree field of view, and make the system has 360 degree panorama and nothing blind-zone monitoring which used two fish-eye lens imaging system. Firstly, this paper designed the panorama imaging system, and then studied the calibration method for it. The hardware system used the multimedia imagery processing chip of TMS320DM6467 which has dual core processor and can processing the fish-eye image real time. The experiment shows the fisheye image had 360 degree sphere with nothing blind-zone for surveillance area and the hardware of processing center can work stable. This system can intelligent surveillance when upload the algorithm.

Abstract: Overhead transmission line temperature monitoring system for the protection of the safe operation of the transmission line is important, this paper introduces the ZigBee protocol level and the network topology, using the existing hardware platform designed and implemented programming ZigBee protocol stack, and then studied and designed based on ZigBee technologies overhead Transmission Lines temperature wireless data collection, gives the overall system architecture and hardware circuits, software systems, and do the experiment. After the unified information platform and experiment, the method is proved to be effective and feasible. The technology has high reliability, scalability, and low operating costs, especially for remote areas of Yunnan, China's high-voltage transmission line temperature monitoring.

Abstract: SVPWM controller is an important part of three-phase inverter. The paper is introduced the realization process for SVPWM controller based on EP3C40Q240C8 FPGA chip. The experimental results show that the control method is valid and feasible.

Abstract: Embedded system is applied more and more extensively in the fields of national defense weapon equipment. With the increasing complexity of embedded systems, the combination of the hardware with software is more and closer. Because of the overall characteristic of hardware and software combination in embedded system, traditional reliability test can hardly accurately identify the reliability of embedded systems. The proposed combined reliability testing method, which combines software reliability test with system integrated environmental stress test to simulate the state of system running, provides the basis for the accurate validation and evaluation of reliability of embedded system.

Abstract: The effects of multipath fading with time delay longer or shorter than one chip interval on DSSS system are mathematically and experimentally researched. Simulation results indicate that DSSS system can efficiently overcome multipath fading in multipath Rayleigh Fading channels. And the spreading gain is not the higher the better, it must be chosen reasonably.

Abstract: With the development of power electronics technology, PWM devices have been widely used. Non-sinusoidal power brings us serious vibration problem. In this paper, vibration acceleration measuring system is applied for detecting the vibration of reactor under SPWM modulated wave.

Abstract: This paper presents the frequency and driving voltage control based on PID controller for wireless power transmission system to restrain the influence of external disturbance and the movement of receiver coil. The phase difference of the voltage and current of the resonant tank is used by the frequency controller to control the frequency of DDS signal source to match the resonant frequency. The received voltage is detected wirelessly by the driving voltage controller to control the output voltage of switching power source to match the power need of the receiver. The experiment platform was built to verify the performance of the controllers. The results show that both controllers could operate normally to improve the stability and safety of the WPT system.