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A compact narrow-band low temperature co-fíred ceramic (LTCC) filter with a fractional bandwidth of 3% is proposed. The proposed filter consists of five cascaded half-wavelength resonators vertically arrayed on each LTCC layer. End-coupling between adjacent resonators is precisely controlled by rectangle-shaped slot on intermediate ground layer. The overall size of the filter is only 8 × 6 × 0.89...
A 3D packaging based 4-channel X-band receiver module is implemented using low temperature co-fired ceramic (LTCC) technology. A dual-mode X-band bandpass filter (BPF), an lumped-element branch-line coupler and an lumped BPF is proposed for the receiver module, respectively. The overall size of the module is only 54 mm × 60 mm × 1 mm. The measured gain parameter, noise figure (NF), image rejection...
The influences of current amplitudes on four-phase 24/18-pole doubly salient electro-magnetic motor(DSEM) under fault-tolerant operation are studied in this paper. Taking average output torque, output torque ripple and stator copper losses into consideration, the optimal fault-tolerant current amplitude (FTCA) range is obtained. A four-phase full-bridge converter with two bilateral switches is applied...
Advanced angle commutation is an effective approach to suppress the commutation torque ripple for doubly salient electromagnetic machine (DSEM). In this paper, the commutation process under “three-phase three-state” conduction mode is analyzed in detail at first. On this base, a novel self-optimizing control strategy of advanced commutation angle for DSEM is proposed, it starts with setting an initial...
This paper proposes a novel rotor angular position estimation method based on self-inductance rectangle for doubly salient electro-magnetic motor (DSEM). It starts with injecting three test voltage pulses A+C-, B+A- and C+B-with the same width in order. At the end of each test pulse, the response currents iac, iba and icb are sampled and detected to identify the two-phase series inductances Lac, L...
In order to solve the excitation and position sensor installment problems for the brushless synchronous machine(BSM) used as starter/generator in the variable frequency AC power system of the civil aircraft, this paper presents a novel integrated method of AC excitation and high frequency injection for the sensorless starting control of BSM. The fixed three-phase 400Hz AC power is adopted for the...
Indirect matrix converter (IMC) has attractive advantages such as lack of dc-link electrolytic capacitor, bidirectional power flow and high power density. Aiming at faulty condition, this paper presents an analysis work for indirect matrix converter (IMC), which could make contribution to detecting the failure accurately. First, some possible types of open-circuit fault are introduced and the current...
In order to achieve the integration of ac/dc output in the aircraft power system, a novel single-input/dual-output indirect matrix converter (IMC) is proposed in this paper. Based on the fact that a real dc-link is formed in IMC, the proposed topology realizes dc output by inserting a simple two transistor forward converter (TTFC) into the dc-link. Its modulation strategy is composed of two parts,...
A compact narrow-band low temperature co-fired ceramic (LTCC) filter with a fractional bandwidth of 3% is proposed. The proposed filter consists of five cascaded half-wavelength resonators vertically arrayed on each LTCC layer. End-coupling between adjacent resonators is precisely controlled by rectangle-shaped slot on intermediate ground layer. The overall size of the filter is only 8 × 6 × 0.89...
This paper proposes a novel sensorless speedup method for doubly salient electro-magnetic motor (DSEM). Based on the characteristic that phase self-inductance varies with rotor position, accurate and quick estimation of rotor sector is achieved through three-phase response currents with only one test injection pulse needed. Besides, no negative torque will be produced by the test pulse unless the...
In the present study, Sn0.3Ag0.7Cu spherical solders with diameter in the range of 10∼50 µm were assembled on the flux-coated Cu metallization and then reflowed at temperature of 250°C to form Sn0.3Ag0.7Cu/Cu micro-bump joints, and the size and boundary effects on the growth and morphology evolution of interfacial intermetallic compound (IMC) of micro-bump solder joints were studied. Results show...
The formation and propagation of void in flip-chip solder joints would reduce the reliability of solder interconnects obviously. Notably, continuously scaling down of the feature size of solder joints may greatly promote the formation and propagation of void in solder joints under electric current stressing. In addition, the elastic stress field induced by the externally applied stress has a big influence...
Creep deformation and fracture behavior of solder joints with a constant diameter (300 µm) and the decreasing joint thickness (from 300 to 25 µm) under electro-thermo-mechanical coupled loads were characterized using a dynamic mechanical analyzer assembled with a DC power source. The results show that the feature of creep curves of solder joints remains unchanged with the decreasing joint thickness,...
This paper proposes a novel nine-switch converter for the dual stator Doubly Salient Electro-magnet Motor (DSEM) in the compact driving system. The dual stator windings are connected to the dual output ports of the proposed converter, and both the operation principle and normal commutation method for the proposed system are analyzed. The interaction of the coupled outputs of the nine-switch converter...
Mechanical properties and strain rate sensitivity of the eutectic Sn-58Bi solder alloy, before and after isothermal aging at 100 °C for 200 h, were investigated. Results show that the grain coarsening occurs in the Sn-58Bi solder alloy with prolonging the isothermal aging time, and the lamellar microstructure of the Sn-58Bi alloy is changed, in which the Bi-rich phase exhibits network-like morphology...
Grain characteristics of copper filler have an important influence on physical properties of through silicon vias (TSVs) in three-dimensional (3D) packaging. Due to the mismatch of coefficients of thermal expansion (CTE) between the copper and silicon, there exist obvious thermal stresses when the TSV structure is bearing thermal load. However, the elastic response characteristics of copper can be...
In this study, core-shell structured SiO2@Ag submicro-sized spheres were prepared and used to improve the performance of the micro-sized silver flakes filled electrically conductive adhesive (ECA). The silica cores with an average diameter of 400 nm were prepared by hydrolysis and polycondensation of tetraethoxysilane using a modified Stöber process. The synthesis of compact silver shells on silica...
Silver nanoparticles stabilized by sodium citrate with an average size of 10 nm were obtained via a modified Carey-Lea method. The synthesized silver nanoparticles were investigated by transmission electron microscope and powder X-ray diffraction. Thermal decomposition and exfoliation of the capping agent from the surface of the nanoparticles were studied by thermogravimetric and differential scanning...
With advantages of non-contact, high energy density and local heating, the laser jet solder ball bonding (SBB) technique provides a flexible packaging method for three dimensional (3D) package structure and temperature sensitive components. In previous works, the microstructure and reliability of solder joints fabricated by laser jet SBB were studied. In recent studies, the essential factors influencing...
To reduce the cost of soldering materials and alleviate the thermal shock of temperature-sensitive electronic components during board-level packaging process, SnBi(Ag) solder pastes were explored to replace SnAgCu solder pastes due to the feature of low melting temperature of SnBi(Ag) solders. In this study, Sn3.0Ag0.5Cu (SAC305) solder balls as IC pins were assembled with SnBi(Ag) solder pastes in...
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