Papers by Keyword: High Power

Abstract: The next space missions require power levels that current space qualified semiconductor technology cannot provide. The silicon carbide devices are considered to overcome these challenges, and provide the required technical performance. European space industry is asked in individual meetings about their specific needs and requirements, this information is gathered, classified and presented to the silicon carbide manufacturers. This work is the connection between the two industries to better understand the requirements and applications, and build a new business case for the SiC devices in space applications.

Abstract: This work presents simple layout configurations for current sensing resistor networks to measure fast and high currents in SiC devices. The proposed layout reduces the inserted inductance in the switching loop when compared to coaxial shunts, which is key for the application of SiC devices in space. High inductance in the switching loop leads to dangerous overshoots during turn-off transients, that can block the adoption of SiC devices in space due to single event burnouts. After presenting the different proposed layouts, the inserted inductance of each one is measured with an impedance analyzer as well as performing switching tests. Applying field cancellation techniques in the layout of a simple parallel resistor network, the inserted inductance is reduced up to 17.6 % when compared to a coaxial shunt, while obtaining the same current sensing performance.

Abstract: The energy level structure and spectral characteristics of Yb-doped fiber laser are analyzed,and the absorption and emission cross sections of ytterbium ions in quartz matrix are given. It can beseen that there are two absorption peaks, 915 nm and 975 nm, respectively. The absorption coefficientcorresponding to 915 nm absorption peak is smaller, but the absorption spectrum is wider. Theabsorption coefficient corresponding to the absorption peak at 975 nm is relatively large, but thespectrum width is very narrow. The advantages and disadvantages of Yb3+ doped laser materialscompared with other rare earth ions doped laser materials are analyzed. It is pointed out that Yb3+itself, due to its strong absorption and emission at 980 nm, disperses the pump power in the innercladding of double cladding optical fibers and reduces the pump efficiency.

Abstract: This paper presents an overview of the main technical requirements of high voltage Silicon Carbide MOSFETs rated above 3300V when compared to the well-established requirements of Silicon IGBTs and diodes. Combined with a performance evaluation of existing 3300 V SiC MOSFET prototypes from ROHM, the paper will discuss the benefits and challenges facing these devices for targeting mainstream and future topologies employed in high power applications such as those in grid systems, railway traction and industrial drives. The paper will also attempt to provide an outlook into potential development trends towards exploiting the full benefits of SiC MOSFETs.

Abstract: The laser source of Lidar usually use the high power solid laser, the performance of Lidar depend on the laser features, so that to study the laser features is contribute to optimize the performance of Lidar. Set up and design a pulse solid laser of Nd³⁺:YAG as the working substance. Through adopt the KTP crystal frequency multiplication technology outside the laser cavity and electro-optic q-switch technique, the maximum dynamic pulse energy of 155mJ and pulse width of 9.6 ns with the 532nm laser is generated. Using the oscilloscope, photoelectric pulse sensor and laser energy meter to measurement the experimental data of the laser source features Through analyze and discuss the experimental data, the relationship between the pulse width, the static and dynamic ratio, the peak power of the pulse Nd³⁺:YAG laser, the frequency doubling efficiency of the KTP crystal and the input power of laser are given, the solid laser system and the experimental data can provide a basic equipment and reference data to the further study.

Abstract: A novel topology for efficient utilization of parallel inverters as current source active power filter (APF) for high-power applications is presented and analyzed. The proposed technique operates the master inverter with high-power low-switching-frequency devices to compensate the low-order large-amplitude current harmonic components and the slave inverter with low-power high-switching-frequency devices to compensate the high-order small-amplitude current harmonic components. This paper discusses the operating principle, main circuit and control system design. Simulation and experimental results are provided to demonstrate the viability of the scheme.

Abstract: According to the requirements of the aircraft power supply equipment, the high voltage DC-DC power converter module is developed. In this paper, the HVDC (High Voltage DC-DC Converter) topology is studied. The starting circuit is designed based on the control chip TL3844. The components parameters are calculated. An overvoltage protection circuit and a current limiting protection circuit are designed to improve the stability of the system. At the same time voltage compensation circuit is designed to compensate the voltage.

Abstract: This paper designs and implements an IEEE 802.11n based mining high power access point to improve the disadvantages of low throughput, low communication distance which are met in current mining communication systems. By adding high power design to transmitting and receiving path, this design can get over more than 190Mbps throughput in lab testing, and can achieve more than 2km outdoor communication distance. Test results show that the mining high power access point is more suitable for mining application.

Abstract: New micromachining techniques now provide the opportunity to fabricate vacuum electron devices with dimensions suitable for operation in the terahertz region of the electromagnetic spectrum. In this paper, results of theoretical and numerical simulation studies of a MW-class, large diameter terahertz backward wave oscillator are presented. A novel full electromagnetic particle-in-cell simulation tool UNIPIC is also introduced. With this method, we studied the device at the frequency of 0.14 THz. It is found that the steady-state, single-frequency operation in this oversized situation could be realized by the property of surface wave near the upper cutoff area.

Abstract: The output characteristics of high power ytterbium-doped fiber super-fluorescent sources were analyzed. 75.7W output power can be achieved when the 915nm pump power is 100W, and the fiber length is 10m.when the pump power changes from 20 to 100W, the backward super-fluorescent power is always larger than the forward. The mean wavelength of the forward and backward super-fluorescent is very stable. The spectrum width all decrease. The spectrum width of forward ASE changes from 24.8nm to 21.4nm when the pump power changes from 20 to 100W. The spectrum width of backward ASE changes from 25.5nm to 22.3nm.