Advanced Materials Research Vols. 383-390

Abstract: In order to reduce the cogging torque in dual-rotor permanent magnet (PM) ring torque motor, the expression of cogging torque is deduced on the motor, and the influence rules of the resulting cogging torque are analyzed with change the inner and outer slot opening widths. According to the dual-rotor PM ring torque machine, the method for reducing the cogging torque amplitude and leading a reverse phase torque curve by suitable selection of the inner and outer slot opening widths is proposed. The results of simulation show that selecting the appropriate slot opening widths can effectively reduce cogging torque by the finite element simulation method.

Abstract: In order to improve the accuracy of the underwater acoustic detection effectively, the digital signal acquisition circuxcA`\\it is a necessary deceive, which must have enough high data acquisition rate. Therefore the high frequency operating clock is employed in the traditional digital signal acquisition circuit. However, the high frequency operating clock will bring troubles to the design of hardware and software, and the power consumption and interference of the system are both increased. According to the principle of the pipelined system, the operation of AD deceive is divided into two process, including the conversion starting and data reading. The FPGA is employed to produce control signals which make twin-AD work in proper state. The design of the underwater acoustic signal acquisition system based on the pipelined twin-AD is presented here. On the base of the system design, simulation, implementation, the hardware experiments are completed. The results show: driven by the operating clock with same frequency, the underwater acoustic signal acquisition system based on the pipelined twin-AD can obtain the acquisition rate which is twice as the traditional data acquisition system.

Abstract: In this article, the general design of external-rotor ferrite permanent magnet BLDC motor is required. Based on the principle of cost reduction, we designed and manufactured motor prototype, and simulated it with the finite element method for electromagnetic field, and had no load and load test to verify the legitimacy of motor design parameters. We made a system test of fan-driven by a prototype, and the measured data showed that the external-rotor brushless DC motor had good performance and lower cost and had the advantages for industrial production.

Abstract: Because of the shortage of the online adjustment of parameters in fuzzy logic controller, a fuzzy logic controller based on particle swarm optimization was presented. Improved particle swarm optimization was used to optimize he numerical factor ke, kec and scale factor ku of fuzzy logical controller online increasing the robustness of overall system and this controller was applied in the control of brushless direct current motor. Controller parameters can be adjusted in TMS320F2812DSP experimental platform on-line, with the advantages of fast response, steady-state error is small and adaptability.

Abstract: Because the high precision ultrasonic flowmeter has shortcomings of expensive, the A/D conversion circuit based on ARM for the time-difference method ultrasonic flowmeter is designed. On the basis of time-difference method ultrasonic flowmeter theory and the domestic and overseas advanced technology, a cost-effective low-power 12-bit ADC12DL040 chip and ARM processor LPC2138 are chosen for the design. According to the data acquisition system issues of the time- difference method ultrasonic flowmeter, the two-channel 12-bit low-power monolithic CMOS analog-digital conversion chip is adopted to design the nanosecond-level high-resolution data acquisition system. In this paper, the A/D chip peripheral pin circuit design is given, hardware structure diagram and software flowchart are also given. The input frequency of ultrasonic signal is 400 kHz and the sampling frequency is 8MHz.The experimental results indicated that the designed A/D conversion circuit is able to accomplish the high-speed and high-resolution ultrasonic echo signal sampling; the minimum resolution time of A/D conversion circuit is 0.305ns. The physical map of A/D conversion circuit for the time-difference method ultrasonic flowmeter is presented. The design of A/D conversion circuit for time-difference method ultrasonic flowmeter not only lower the production cost, but also lays a solid foundation for the research of low-cost and high-precision time-difference method ultrasonic flowmeter.

Abstract: Geomembranes are installed on the bottom and sides of a landfill to protect the surrounding ground and water from being polluted by the leachate from the waste. Geotextile is also placed over the geomembrane to protect it from mechanical damage. In order to evaluate the tensile forces of geotextile and geomembrane, centrifugal model tests were conducted in the laboratory. This paper presents the results of these centrifugal tests and compares them with the calculated values based on the ordinary ultimate force equilibrium method and FEM analyses.

Abstract: In this paper, a type of control system of coke machine interlocking and automatic running on PLC is proposed. The control principle, system configuration and application is introduced in detail. The design method of hardware and software on PLC is given, which is useful for the application of control system. The whole system is based on induction radio communication. It has proved that this system has the characteristics of advanced design, complete functions and high stability. It also could bring about vast economic and social benefit.

Abstract: Brushless Doubly-fed Machine (BDFM) is a new inverter-driven induction motor, and it has broad prospects in wind power generation. This paper analyses the structure and VSCF electricity generating principle of a cascade Brushless Doubly fed Wind Power Generator, deduces the BDFG’s mathematical model, The variable structure control (VSC) was used to the active and reactive power decoupling control of the BDFM, analysis the relation of electromagnetism and energy balance .Finally, simulation and analysis of the whole system and control strategy are carried through in matlab/simulink soft. According to these results, the correct of parameters and simulation model for BDFM is proved.

Abstract: This paper studies the control strategy of STATCOM with LCL filter. The STATCOM sixth orders differential equations in dq coordinate separate to two parts. Invert system theory deals with their uncoupling and nonlinearity. Then the sliding mode control strategy is used to the differential equations. Finally simulation results show validity and effectiveness of the design by comparing with PI controller.

Abstract: Crash sense module of vehicle emergency call system determines whether or not the system can sense accurately the accident happened in time. Based on the function requirements of crash sense module, this paper researched on its software and hardware so that implemented the serial communication between MCU and LabVIEW. And the result of sled crash test shows the reliability of software and hardware of crash sense module.