Applied Mechanics and Materials Vols. 672-674

Abstract: According to the working principle of the Boost type switch converter, the small signal analysis method was used to model the Boost circuit. Its transfer function exists right half plane zero. The system is a non-minimum phase system. A PI regulator was designed. The boost circuit simulation model was built through matlab. The simulation result has a good static and dynamic performance. It verifies the rationality of the mathematical model and control strategy. It can conduct the actual circuit design.

Abstract: 3D printing, is a kind of rapid prototyping manufacturing, fabricating expected objects by way of cumulative constructed layer by layer, based on digital model files and powdered materials used. In this paper, the controller of desktop 3D printer is designed and carried out, both from the hardware and software part. For hardware design, a 32-bit ARM core microcontroller, STM32F103VB is selected as the core, supplemented by stepper motor driver chips, thermocouple digital converters and other devices, which build a desktop 3D printer controller panel. For software design, referred to open-source design being based on the AVR microcontroller, the whole process of 3D printing is accomplished by programming the ARM core microcontroller.

Abstract: In the paper hardware and software of lighting control system are designed within the office building based on C-bus. In terms of hardware design, C-bus controller is chosen as the main control part of the whole process to implement the lighting dimming control. In the aspect of software design, the use of C-bus programming software can realize the characteristics of the complete set, multi-channel dimming light and infrared induction control implementation. The black and white touch screen is used to complete the multi-channel dimming of parameter settings and information display.

Abstract: To protect dwindling coal and oil resources and open up a new way of renewable green energy, the technology of piezoelectric harvesting from pavement is proposed. Effect of traffic flow, including contact pressure and speed of a vehicle, on characteristics of a piezoelectric harvesting unit is discussed with the finite element method. Results show that the harvested electric power is approximately linear with the contact pressure and a vehicle’s speed. The contact pressure takes more effect on the harvested electric power and stress on pavement than the vehicle’s speed. A PHU of 280*280*20mm can harvest about 10mJ electric power when the contact pressure is 0.85MPa. That shows that application of the piezoelectric harvesting unit has very nice optimistic prospects.

Abstract: SiC MOSFETs are expected as one of next generation power devices for their superior performances compared with conventional Si power devices and have become one of the new promising substitude to Si devices. The characteristics of 1200V SiC MOSFET are presented first and the power losses analysis model of SiC devices are given. As losses of power devices are essential parameters in converter design, the power dissipation of SiC MOSFET in SPWM inverter are calculated. In this paper, whether a free-wheeling-diode necessary is illustrated from the point of power dissipation and choice is made based on the power loss. According to the analysis result, the inverter without SBD shows less power losses, which can reduce the cost and volume of inverter.

Abstract: Converter transformer is one of the most important equipments of UHVDC power transmission system, its faults directly affects the safe and stable operation of DC system. The valve winding of converter transformer needs to withstand the voltage that consist of DC voltage and serious distortion of AC voltages (harmonic bound) which are similar to the AC sine waveform compound voltage, so in the design and manufacture of the valve side of converter transformer, bushing is much more complex and difficult than alternating current casing. Valve bushing is weak spot of converter transformer insulation. Through the anatomy of failure bushing, the reason of bushing failure is analyzed. Without changing body size of the converter transformer, the bushing of new structure is developed and the old bushing is replaced to improve the reliability of equipment operation.

Abstract: Design a battery with a power factor correction two level converter structure of charging power supply .Discuss the design scheme of main circuit and control circuit. Expound the calculation method of the key element parameters. The experiments indicate that the device get a good performance on output and reliability. The source is appropriate for all types of Battery charging.

Abstract: In civil defense engineering, three anti-ventilation, air conditioning dehumidification, power supply and other electrical control equipment have long distance, distributed monitoring area and are not convenient for centralized monitoring. To improve the level of civil air defense system of automatic monitoring, enhance the system's rapid response ability, adapt to the need of modern war, this paper based on data communication problems of distributed electrical system in civil defense engineering, combined with the low communication rate and high security requirements in civil defense engineering, puts forward the communication solutions based in Siemens PPI fieldbus, configures the communications PLC which has powerful functions, compiles multipoint PPI communication program, designs remote monitoring system and gives results of test analysis when it is running. Actual operation results show that the communication system of civil defense engineering based on Siemens PPI fieldbus has fast communication speed, low error rate, strong expansibility and other advantages..

Abstract: Analysis strategies of nonlinear electromagnetic interference have always been a focus in the literature. This paper designs a identification of scattering pattern by using a improved least squares method (LLM) combined with method of moment for mutual coupling among inner elements and interactions with outside scatterers. The novel LLM is applied to optimize the radiation pattern of arbitrary arrays in the operational environment as well as represses the array gain and phase tracking error caused by electromagnetic compatibility based constraints. The algorithm has a simple control structure and enhances the robustness of the electrical system, and the experimental results based on dSPACE testify its reasonability and validity.

Abstract: Using DC current sensor as current detecting element in leakage protective in underground LV distribution network and single chip processor as central control unit,a new computerized DC examination and selective leakage protective system is formed. Hardware and software designs are introduced in the essay. The simulated experiment results show that all the property indexes of the system reach the design requirements and achieve good results.