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In this paper, an investigation of arc root behavior on a pair of parallel electrodes is presented. An effective filtering method is introduced to allow the clear observation of arc root behavior. The position of the arc root is identified and tracked by a multi-objective dynamic tracing algorithm. Thus the trajectories and the speeds of arc roots can be obtained. The results show that the movement...
RF technology is widely used in many fields. This study is based on the knowledge of RF circuit. It is aimed to design a wireless communication transceiver, which includes transmitter circuit, receiver circuit and communication antenna. In design process, we do not only consider the transmitter circuit and the receiver circuit indicators to meet the requirements of the module, but also ensure that...
The softness and the switching losses are the key characteristics to evaluate the quality of the ultra voltage power diodes, especially for high frequency application. In this paper, we applied the Controlled Injection of Backside Holes (CIBH) structure to the 10kV SiC diode based on TCAD, by which, the softness and snap-off characteristics of the diode is significantly optimized compared with conventional...
Vehicle detection is the core function in any Driver Assistant System. Besides the challenge in various environmental conditions, the limitation in execution time and computing power is also critical. This paper proposes a shadow detection step that aims at recognizing the shadow part of the train in various environments (including very tough cases) to accelerate the detection process. We propose...
Aiming at the capturing difficulties for space satellites caused by pose error of the manipulator, a design method of modular reusable locking-release devices based on error field analysis is proposed in this paper. Firstly, error field of the captured trunnion at the bottom of the satellite is analyzed based on the pose error of manipulator terminal and the trajectory of the trapping component is...
This paper investigates the problem of cooperative formation control of unmanned surface vehicles (USVs). According to the second-order consensus protocol with a virtual-leader, a distributed control law is derived, in which the consensus formation motion information can only be obtained by a part of USVs. Taking advantages of the shared information between adjacent multi-USVs, the USVs can control...
Active disturbance flow control system depended on the ability of small square-edged rectangular flow effector (FE) generates aerodynamic forces by triggering or stabilizing the FE structures. Computational analysis is performed for supersonic flow runs through a generic slender body equipped with micro-structure on its nose cone. Computational Fluid Dynamics (CFD) studies show that a proportional...
The repeated locking-releasing device is used to extend the application range of payload in space. A repeated locking-releasing device with a slider crank mechanism and an electromagnetic device is presented. The key components, including the support and slider crank mechanism, are optimized. The simulation analysis is carried out to get the kinematics characteristics of this device. The sample is...
Picosatellite deployer is used for carrying and releasing picosatellites during the launching and in space respectively. For releasing several picosatellites placed in one deployer controllably, one design scheme based on memory alloy spring is presented to make arbitrary picosatellite have the same separation velocity with combination springs. The key components of deployer are optimized and its...
A novel slow-light reflector composed of a double ring resonator with a fiber Bragg grating (FBG) incorporated is proposed in this paper, which can be used as a mirror of narrow linewidth fiber laser. Due to the Vernier effect, it is shown that the amplitude of resonance peaks is modulated by the simulations and the mode spacing is expanded greatly. Compared with the case of single ring, the mode...
Through investigating the status of information management of laboratory equipment in a certain aerospace scientific research unit, analyzing the backwardness of its equipment information management mode, low efficiency and high error rate, this paper puts forward the application of RFID(Radio Frequency Identification) technology in the laboratory, combining visualization, data mining technology and...
In this paper, a low parasitic inductance SiC power module with double-sided cooling is designed and compared with a baseline double-sided cooled module. With the unique 3D layout utilizing vertical interconnection, the power loop inductance is effectively reduced without sacrificing the thermal performance. Both simulations and experiments are carried out to validate the design. Q3D simulation results...
Coupling factor is a important design parameter in inductive power transfer (IPT) systems as it determines the amount of VA effort required from the primary pad to deliver the necessary VA to the secondary pad. As IPT systems involve more complex magnetic systems such as multi-coil primary pads (whose currents can have an amplitude and phase difference), the effective coupling factor becomes more...
All engineering surfaces are of certain degree of roughness and comprising asperities of various size. When two rough surfaces contact with each other, the contact load will be dispersed by numerous contact spots generated by the compressive deformation of asperities. Weierstrass-Mandelbrot function is widely used in fractal contact theories to model the roughness and self-affinity of engineering...
In this paper, we comparative analysis the performance of DFT-based interpolation algorithm with different windows and Digital Lock-in amplifier(DLA) method. We recommend that DLA is a good choice for low signal to noise ratio (SNR). DFT-based interpolation can work with unknown frequency. In comparison with rectangle window, triangle window has better side-band affection with accuracy lose. Beside,...
As electrolytic capacitor is apt to fail in power system, it is very important to monitor its ESR and C. A novel online monitoring method of capacitor's ESR and C for DCM Flyback Converter is proposed in this paper. Based on the ac component of capacitor voltage, the calculation model is founded. The method needs no current sensor and is effective for the converter operating at any switching frequency...
The conventional Buck PFC converter adopts constant duty cycle control (CDCC), which can improve the PF to some degree. However, the peak and RMS values of the inductor current are large, which also occurs to the switch and diode. This paper derives the expressions of the input current and PF of DCM Buck PFC converter, and based on which, a kind of injecting 3rd current harmonic control (ICHC) is...
This paper presents a localization and recognition method for railway oil tank wagon ID in the industrial scene. Firstly, we use the maximum stable extremal regions (MSER) algorithm to obtain the extreme regions, and extract effective areas from the extracted extremal regions. Then the effective areas of the regions are merged into triplets region sequence as an ID candidate region, and we select...
▪ For wirebond connections, the total parasitic inductance value cannot be effectively reduced simply by increasing the number of wirebonds. ▪ A method to extract the power loop inductance is discussed in detail for a 3D PBA module. ▪ It is observed in simulation that power loop inductance's value is varying.
In this paper, the parasitic inductance extraction method is studied in detail. It is analyzed that the value of the lumped power loop inductance will be varying at different switching transients. With the aid of Ansys Q3D Extractor, different values of lumped power loop parasitic inductance are obtained at different time intervals during turn-off process for both upper and lower devices. A dedicated...
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