Advanced Materials Research Vols. 516-517

Abstract: This paper presents a Repeated Pulsed High Magnetic Field (RPHMF) generator for frequency-tunable terahertz sources, which mainly consists of a charging power supply, a capacitor bank, a discharging switch, a bitter magnet and other facilities. The four thyristors (80 mm, 4 kV) in series with a self-supplied gate driver are taken as the discharge switch which can be triggered when the high voltage capacitor C was charged to 300 V. Meanwhile, a bitter magnet with fast heat dissipation was designed and fabricated. According to the experiment, the designed system has a pulse repetition frequency of 0.1 Hz with a maximum magnetic field of 9 T.

Abstract: Copper alloy C194 lead frame occasionally has been observed creates non-sticking defect at wire bond process in typical microelectronic assembly line. The effect was significantly assessed as process variation during die attach. In this study, microstructure and mechanical properties of copper alloy lead frames were investigated. The copper alloy lead frames were selected from different batches in the production line that produced sticking (typical performance) and non-sticking defect. The micro structural and structural properties were investigated by means of optical microscopy (OM) and X-ray diffraction (XRD), respectively. The hardness and tensile strength were also determined. The result revealed that non-sticking lead frame has larger grain size of 43.8 nm than typical performance lead frame. Due to lower dislocation density, tensile strength and hardness of typical lead frame with smaller grain size were higher than that of defect lead frame. Elongation of defect lead frame was reached above 10% as compared to typical performance lead frame groups with the value below 4%.

Abstract: This paper presents a dual-mode control scheme for a boost rectifier at both extreme loads. The transition-mode (TM) technique is adopted to reduce the switching loss at light loads. On the other hand, the fixed-off-time (FOT) control with continuous conduction mode (CCM) operation decreases the conduction losses at heavy loads. The principles and design procedures of the proposed dual-mode controller are discussed and analyzed. Finally, a 300-W dual-mode boost rectifier with an output voltage of 380 V is implemented with satisfactory experimental results.

Abstract: Liquid desiccant cooling system is a novel air conditioner with good energy saving potential, which should be a promising choice to meet the needs of cooling and moisture loads. Among all regeneration methods, ED regeneration method should be a promising choice for liquid desiccant cooling system. In this paper, systematic experiments were carried out to investigate the electrical conductivity of desiccant solution. Experimental data of electrical conductivity of desiccant solution is acquired in the experiment, which will be greatly helpful to the energy analysis of ED regeneration system. The experimental results show that the energy consumption in the concentrated chambers is more than others for ED regeneration system cells. Moreover, increasing the temperature of desiccant solution may be a measurement to reduce the energy consumption of ED regeneration system.

Abstract: Metal-oxide-semiconductor (MOS) structure is highly sensitive to SiO₂-Si interface. It will reflect parameters such as interface density and oxide layer charge expediently. For the sake of researching of radiation effect of MOS structure irradiated by electron, we adopted 0.8 MeV electron at dosage between 2×10¹³ cm^-2~1×10¹⁴ cm^-2 as radiation source respectively. We found that electron radiation will induce interface density at SiO₂-Si interface. According to comparison with C-V curve of MOS structure at high frequency and low frequency, we obtain that the experimental data of interface density is up to 10¹⁴(cm^-2eV^-1). In addition, we also obtain the relationship between the parameter and radiation dosage.

Abstract: Wind power generation was developed rapidly in China. And many wind farms are configured Dynamic Static Var Compensators (SVCs) as reactive power compensator, which can meet the dynamic demands of the reactive power compensation for the wind farm. The paper put forward a coordination control strategy of reactive power for wind farm based on embedded real-time operation system in DSP, and by using LabVIEW to realize PC management and network communication management, and provides the research foundation for coordination and the optimal control of reactive power in large wind farm.

Abstract: with the higher mobility in many developing country, the vehicle volume, vehicle use frequency are rapidly increasing, driving skill training becomes one key factor for vehicle security and use quality. By the comprehensive application of electron, computer, network technology, the supervision, control and guidance can be done to realize the intelligent dynamic management in driving training and standardized test, which promotes the students to obtain the optimal training effect in the possible shortest time, to provide a method to improve the overall driving quality.

Abstract: Power balance control strategy is applied to a novel AC-AC converter. The simulated model was established based on the power balance. The paper analyzed the input/output characteristics of AC-AC converter under different power factor. The results show that decoupling the active and reactive current, the power factor can be regulated under power balance control, and it is able to avoid the phase-shifting from the input filter. And in inverter stage, the system applies the complex vector model control to obtain the better dynamic performance and stronger robustness.

Abstract: An asynchronous motor is widely used in traction locomotive system now, AC induction motor is nonlinear, strongly coupled and multivariable system, so it is very difficult to control as a linear system. For this, VVVF(Variable Voltage Variable Frequency) control method adopt in some running traction locomotives, that can reduce over-current with load starting and should be compensated at low frequency. Based on study the Control strategies of locomotives, vector control adopt in most electrical traction locomotive. According to the drawing performance requirements of electrical traction motor, feed-forward decoupling method adopted. Simulation and experiment proved this method can meet the traction locomotive control requirements.

Abstract: Repetition pulses with sub-microsecond arising time, high voltage and large current, have been widely utilized in the field of production and scientific research, in which the gas spark switch is usually selected because of the large state current and the high operating voltage. However, due to the recovery property of gas ionization, it is hard to get the repeated switch-on and switch-off at a high rate towards the conventional gas spark switch. Owing to the reliably triggering and faster arising time, the hydrogen thyratron is found to be more suitable for the switch to generate the repetition pulses at a high rate. In this paper we proposed a novel design of repetition pulses, in which it gets a several times high voltage output based on the inductive-adder, by using the hydrogen thyratron switch with a low operating voltage, and then we analyze the magnetic field distribution under the structure of the coaxial cable and describe the design of high voltage repetition pulses in details