Applied Mechanics and Materials Vols. 241-244

Abstract: Designed an intelligent controller for FMC, this kind of intelligent controller can provide a variety of functional interfaces. Connected to the MCU and operated by the MCU will be very convenient. It provides DMA channels, which are used to transfer large data blocks. Most of the FMC can be easily controlled by the intelligent controller. It can be a separate hardware or combined in a smart chip with the FMC.

Abstract: With the development of electronic technology, the signal generator used in most of the lab employs direct digital synthesis (DDS) technology. The signal generator using digital technology has advantages of high resolution and short conversion time and so on [1, 2]. Through ARM chip STM32F103VET6, we realize the control to the chip AD5791. At the same time, it engender high-accuracy periodic e exponential decremented signal. Doing above, we correct transient electromagnetic system which has been manufactured. The output signal amplitude is 5V. Frequency can be adjusted according to the sampling points and sampling time of the receiving device.

Abstract: In this paper, the principal and application of digital frequency synthesizer are analyzed firstly. Then, the phase truncation error of phase accumulator is discussed theoretically and is eliminated by the real-time scrambling code from Linear Feedback Shift Registers (LFSR) for the purpose of engineering. At last, a new method combined difference method with coarse and fine lookup table (LUT) is proposed to reduce the length and amplitude of LUT. From the simulation of the new method, it is found that the LUT is reduced from 2^14*16 bit to2^10*14 bit and 2^14*7 bit. Also, the spurious free dynamic range of the power of output signal is more than 100dBc.The method can meet the request of project efficiently and save a lot of cost.

Abstract: One method called “low-order digit decided by high-order digit” is introduced to be applied to equilibrate AC electric bridge with two adjustable parameters frequently encountered in college physics experiment. The full verification of this method is discussed intuitionally. It is indicated that one can eliminate some disturbance of noise and improve measurement precision by using this method.

Abstract: NetGap is used to physically isolate the interior-net and the exterior-net, and protect the information transferred between the interior-net and the exterior-net through the electric mobile access system. This paper first introduces the background of the mobile access system and the basic principles of netgap, then analyzes why gap should be used in the mobile access system. Finally, the solution and policy configuration of netgap used in the mobile access system are given.

Abstract: In this paper, an energy recovery for plasma display is proposed. The proposed energy recovery sustainer provides soft-switching of main sustain switches and reduces the switching loss. Due to soft-switching characteristic, the switching losses of main switches are significantly reduced. In addition, the conduction losses in both main and auxiliary switches are effectively reduced by varying a current build-up time according to image patterns. Theoretical analysis and performance of the proposed energy recovery sustain driver were verified on an experimental prototype operating at 200 kHz switching frequency.

Abstract: This paper developed a mathematical model of three-phase PV grid-connected inverter, and studied the grid-connected current control method based on PI control in synchronous rotating reference frame. Simulation and experimental results from the prototype of 30kW three-phase PV grid-connected inverter proved the correctness and the feasibility of the control strategy, and this grid-connected inverter can operate at the unity power factor state with a nice dynamic performance, and the output current has high sinusoidal and low harmonic content as well as good symmetry.

Abstract: A phase compensation method based on signal transfer principle of electronic transformer is presented. The causes of phase error in electronic transformer are analyzed. The phase-delay caused by Rogowski coil and time-delay in signal transferring process from high voltage side to merging unit are analyzed. A phase compensation method is proposed based on high sampling rate and linear interpolation. The simulation result verifies the effectiveness of the proposed compensation method for electronic transformers.

Abstract: In order to achieve MTFs at different contrasts, the MTF measurement system is designed and developed. Two integrating spheres are used to illuminate the face and back of the test target uniformly. The target luminance and background luminance of the test target are regulated by adjusting the attenuators near the entrance of each integrating sphere. The many groups’ experimental results indicate that the luminance differences between the values by the system and those by L88 first level luminance meter, which is checked by National Institute of Metrology P. R. China, are within ±0.3 cd/m2. Thereby the measurement precision can be ensured in MTF test. MTFs of Sony camera and Cannon camera at different contrasts are measured by this system. The measurement values show that MTFs at different contrasts can demonstrate the imaging quality fully and objectively. This study provides an effective method to evaluate the imaging quality of visible imaging systems.

Abstract: Electrostatic precipitator is the efficient dust removal equipment for environmental protection. As the core part, high voltage inverter power supply determines the efficiency and effect of dust removal. This paper design a high frequency and high voltage switching power supply for electrostatic precipitator based on FPGA. The power supply system is composed of rectifier and filter circuit, high frequency inverter circuit, step-up transformer and high voltage rectifier silicon reactor circuit. Using IRFP460N as power switches, single-phase full-bridge inverter was set up. The SPWM signals produced by FPGA EP2C5T144C8 were isolated and amplified through drive circuit IR2110. The function of variable frequency and voltage was realized. Hardware test showed the whole system operated safely and reliably.