Applied Mechanics and Materials Vols. 548-549

Abstract: In order to overcome the defects of the high computational loads and selecting the threshold of mean square error (MSE) for time domain decision-directed constant modulus blind equalization algorithm (DD+CMA), a frequency domain parallel decision multi-modulus blind equalization algorithm based on frequency domain MMA(FMMA) and frequency domain LMS (FLMS) algorithm is proposed. The proposed algorithm is composed of the FMMA and FLMS, and the FMMA and FLMS run automatically in soft switching parallel manner. In running process, it is not necessary to selecting the threshold of the MSE. Moreover, the computational loads can be reduced by circular convolution in the frequency domain signals instead of linear one of the time domain signals. Simulation results show that performance of the proposed algorithm outperforms the FLMS and the FMMA algorithm.

Abstract: The impedance of a horizontal Extremely low frequency (ELF) line-current antenna is studied. A new analytic expression for calculating a grounding resistance in any shape of ground screen in a two-layer earth is proposed, model adapted to a bed-rock with high resistivity. Its calculated accuracy has a significant improvement compared with previous literature. The radiation resistance of an ELF line-current antenna over inhomogeneous anisotropic ground is researched. The effect of anisotropy of the ground conductivity on radiation efficiency of an ELF line-current antenna is analyzed. The obtained results have important purpose in engineering design of ELF horizontal antenna path.

Abstract: The deployment of the wireless technology since FCC regulated the UWB technology spectrum was going rapidly. The wireless system that supports UWB, especially the antenna as the transducer should be UWB supported beside the other existed wireless technology, ease to fabricate and low cost. Not only that, The antenna performance should be has circular polarization to reduce misalignment. With the dimension of 60 x 60 mm made from FR-4 epoxy 0.8 mm thickness, and L-shape for the feedline with the star shape as the patch, the microstrip antenna can work at the frequency of 2 up to 9.8 GHz and has circular polarization in the frequency range of 2 up to 3.3 GHz.

Abstract: A compressed multiple band loop antenna that has multiple superimposed compressed loops. Each compressed loop is formed from numerous segments arrayed in multiple diverse directions so that the enclosed area of that loop and the overall size of the antenna are decreased. Multiple loops are arrayed and superimposed to provide multiple frequency bands of operation and are used to broaden the useful bandwidth of individual-bands. The small size of the compressed antenna facilitates its use in small mobile communications devices requiring internal antennas that operate in close proximity to conductive surfaces. Multiple loops are arrayed in several configurations that include nested and non-nested loops as well as closely located and spatially separated superimposed loops.

Abstract: This paper discusses about the modeling of frequency coded serial communication for the application of Eurobalise on hardware-based field programmable gate array (FPGA). The transceiver consists of FPGA and the ultra-high frequency (UHF) band amplitude shift keying (ASK) module. In the convention interface of the ASK transceiver module with the digital controller, noise has introduce into the channel. The noise in the output of ASK receiver has distorted the transmitted data causing the throughput of the wireless channel to be decreased. When the ASK module interfaces with the FPGA device, the noise from the output of the ASK receiver causing the receiving FPGA retarded. The purpose of the frequency coded serial data is to provide continuous specific frequency pulse train to the ASK transmitter. The original serial bit stream is then modulated in the pulse train with different frequency corresponding to the bit’s logic level. This technique has made the output of the ASK receiver to produce a very clean signal with extremely less noise. Hence, the receiver’s FPGA able to capture all the transmitted data accurately across traditional disciplinary boundaries, including computer hardware, algorithms, electronics interfacing and application domain.

Abstract: In order to promote improvement in the applicability, quality and economic rationality for ATSE with dual power supply, the design method based on the notion of inverse form is proposed in this paper. The component-based inverse form innovation design concept for ATSE with dual power supply is discussed by theoretical analysis and applicable study with two examples, after this paper expresses the importance of product innovation design, including innovation design of ATSE with dual power supply. Especially, ATSE innovation design process with component-based inverse form is researched in detail. Next, some useful and basic advices on how to optimize ATSE products by the notion of inverse form are stated. At the same time, this paper also points out that the structure of ATSE product becomes more reasonable by appropriate use of the innovation design method with inverse form.

Abstract: With the more penetration of wind power based on the DFIG wind turbine to the grid, there is increasing significance for controlling output power in order to meet power system requirements and to participate the frequency regulation in the power grid. This paper is presented proposed control method of DFIG implemented in the RSC using system frequency coordinated control. In this study, the GSC is controlled by using modified vector control method while the RSC is controlled by adjusting the rotor dq-axis currents. The quadrature axis current controls by using the active power generating from the frequency deviation and DFIG store kinetic energy, whereas the direct axis current is controlled by using grid reactive power. Moreover, this power is also used as a main parameter besides rotor speed to control the pitch angle blade in the turbine side. To confirm this method study, the system operation is conducted at steady state and transient modes, and the simulation results were carried out using PSCAD software program. The simulation results show that the voltage of DFIG is very stable, and the system frequency response has been improved. Furthermore, this study realized a full rated value of rotor speed and stable operation of DFIG active power at a steady state besides a good transient response. Moreover, the pitch angle control provided adequate control action at dynamic mode to decrease turbine torque hence to lead to safety transient mode operation.

Abstract: The SVPWM technique plays an important role in the DC-AC transform. The modeling and simulation for SVPWM were proposed in this paper. The sector calculating model and basic vector working time model were set up. The effective vector function of time was set up. The triangle wave symmetry modulation was established too. The simulation results show that the model proposed in this paper is effective and has application value.

Abstract: In the AC control system, vector control theory is very popular as it makes the AC motor achieve the performance as perfect as DC motor [1]. In the paper, the vector control theory is briefly introduced, and then a vector control system model is builded in the matlab/simulink, and the SVPWM technique is adopted. The results show that the improved vector control sytem of PMSM has a excellent performance.

Abstract: Smart phone has various function and large display for convenience. However, there is some disadvantage that the smart phone is less portable than before. The thickness of the smart phone should be reduced in order to improve the portability of a smart phone. The vibrating motor is one of the thicker components in a smart phone. Therefore, we develop a horizontally vibrating linear motor that can be used to reduce the thickness of a smart phone. In order to develop a horizontally vibrating linear motor (HVLM), Mathematical vibration modeling is used, and a finite element analysis using the commercial electromagnetic analysis software MAXWELL. Also, the guide spring is designed using commercial structural analysis software ANSYS workbench. Finally, a prototype is manufactured for use in experiments. Its thickness is reduced by 30 % compared to a vertical linear vibrating motor. In addition, the motor can vibrate with an acceleration of approximately 2.10 Gravity (G).