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1.
Analytical and experimental considerations of the large-signal transient responses of the buck-type switching regulator are described. The dynamic behavior under the large-signal condition is different from the small-signal operation because of the saturation characteristics of the pulsewidth modulator feedback controller. The effect of this nonlinearity is analyzed by dividing its operation into three modes. As a result the peak values of the inrush current and output voltage are obtained analytically both for the start-up and for the step change of the load condition. 相似文献
2.
W. Miyake Y. Saito M. Harada M. Saito H. Hasegawa A. Ieda S. Machida T. Nagai T. Nagatsuma K. Seki I. Shinohara T. Terasawa 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009,43(12):1986-1992
The Mercury Magnetopsheric Orbiter (MMO) is one of the spacecraft of the BepiColombo mission; the mission is scheduled for launch in 2014 and plans to revisit Mercury with modern instrumentation. MMO is to elucidate the detailed plasma structure and dynamics around Mercury, one of the least-explored planets in our solar system. The Mercury Plasma Particle Experiment (MPPE) on board MMO is a comprehensive instrument package for plasma, high-energy particle, and energetic neutral particle atom measurements. The Mercury Ion Analyzer (MIA) is one of the plasma instruments of MPPE, and measures the three dimensional velocity distribution of low-energy ions (from 5 eV to 30 keV) by using a top-hat electrostatic analyzer for half a spin period (2 s). By combining both the mechanical and electrical sensitivity controls, MIA has a wide dynamic range of count rates for the proton flux expected around Mercury, which ranges from 106 to 1012 cm−2 s−1 str−1 keV−1, in the solar wind between 0.3 and 0.47 AU from the sun, and in both the hot and cold plasma sheet of Mercury’s magnetosphere. The geometrical factor of MIA is variable, ranging from 1.0 × 10−7 cm2 str keV/keV for large fluxes of solar wind ions to 4.7 × 10−4 cm2 str keV/keV for small fluxes of magnetospheric ions. The entrance grid used for the mechanical sensitivity control of incident ions also work to significantly reduce the contamination of solar UV radiation, whose intensity is about 10 times larger than that around Earth’s orbit. 相似文献
3.
The optimum design of an RC snubber to suppress the surge voltage across the transistor in a switching regulator with a two-winding reactor is presented. Analyzing the surge voltage by means of high-frequency equivalent circuits, we obtain the third-order characteristic equation. This third-order equation is first analyzed by the aid of the root locus method. As a result, the region where the surge voltage can be suppressed is described in the R-C plane. Then considering the snubber loss, the optimum resistance and capacitance can be obtained. Second, the precise design procedure of RC snubbers is discussed by normalization and numerical calculations. This procedure is summarized in easy-to-use nomographs. 相似文献
4.
Analytical and experimental considerations of the common-mode noise in a dc-to-dc connverterare discussed. Analyzing the mechanism of the common-mode noise generation by means of a high-frequency equivalent circuit, we estimate the output noise voltage generated during the transistor's turn-on time. This commonmode noise consists mainly of two frequency components distributed in several megahertz. The effects of parasitic parameters on the noise voltage and frequencies are clarified. In addition, the effect of a common-mode choke on the noise suppression is discussed experimentally. 相似文献
5.
The new dc-to-dc converter driven by the external pulse is presented. The principle is based on the synchronizing phenomenon in the transistor core multivibrator. There are the voltage feed- back in the OFF interval and the current feedback in the ON interval. The flux of the saturable core is changed along the minor hysteresis loop. The operations are explained by the aid of the averaged method of the state space technique. The efficiency of this converter is high and the construction is very simple. 相似文献
6.
Nakahara M. Ninomiya T. Harada K. 《IEEE transactions on aerospace and electronic systems》1985,(5):619-630
Switching surge and noise voltages are analyzed under the common-mode condition in a forward dc-to-dc converter. The analysis is performed by partitioning the switching time into several states and introducing the high-frequency equivalent circuits. The equivalent circuits include not only inductive and capacitive parameters, but also the parameters related to the switching speed of the transistor and the recovery characteristics of the diode. As a result, the effects of these various parameters on the surge and noise generation are made clear quantitatively. 相似文献
7.
Harada K. Ninomiya T. Nishi H. 《IEEE transactions on aerospace and electronic systems》1979,(2):260-266
Analytical and experimental considerations of the noise suppression characteristics of a typical dc-to-dc converter with a two-winding reactor are described. The high-frequency equivalent circuits for external noise are presented which are composed of parasitic parameters and have parallel and series resonances. The high-frequency responses calculated from these equivalent circuits agree well with the experimental results. Effects of the parasitic parameters on the noise suppression capability are discussed. 相似文献
8.
Jianguo Yan Fei Li Jingsong Ping James M. Dohm Yuji Harada Zhen Zhong 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
An improvement to the Martian gravity field may be achieved by means of future orbiting spacecraft with small eccentricity and low altitude exemplified through a newly proposed mission design that may be tested in upcoming reconnaissance of Mars. Here, the near equatorial orbital character (with an inclination approximating 10°, eccentricity as 0.01 and semi-major axis as 4000 km) is considered, and its contribution to Martian gravity field solution is analyzed by comparing it with a hypothetical polar circular orbiter. The solution models are evaluated in terms of the following viewpoints: power spectra of gravity field coefficients, correlations of low degree zonal coefficients, precise orbit determination, and error distribution of both Mars free air gravity anomaly and areoid. At the same time, the contributions of the near equatorial orbiters in low degree zonal coefficients time variations are also considered. The present results show that the near equatorial orbiter allows us to improve the accuracy of the Martian gravity field solution, decrease correlation of low degree zonal coefficients, retrieve much better time variable information of low degree zonal coefficients, improve precise orbit determination, and provide more accurate Mars free air gravity anomaly and areoid around the equatorial region. 相似文献
9.
Six modes of operation for the push-pull 4c-to-dc converter are presented by taking into account the magnetizing current of the transformer. If the inductance of the transformer is decreased, the region where the output voltage is abnormally high is expanded in the load characteristics. 相似文献
10.
Hideo Hanada Takahiro Iwata Qinghui Liu Fuyuhiko Kikuchi Koji Matsumoto Sander Goossens Yuji Harada Kazuyoshi Asari Toshiaki Ishikawa Yoshiaki Ishihara Hirotomo Noda Seiitsu Tsuruta Natalia Petrova Nobuyuki Kawano Sho Sasaki Kaori Sato Noriyuki Namiki Yusuke Kono Kenzaburo Iwadate Osamu Kameya Katsunori M. Shibata Yoshiaki Tamura Shunichi Kamata Yukihiro Yahagi Wataru Masui Koji Tanaka Hironori Maejima Xiaoyu Hong Jinsong Ping Xian Shi Qian Huang Yusufu Aili Simon Ellingsen Wolfgang Schlüter 《Space Science Reviews》2010,154(1-4):123-144
The Japanese lunar explorer SELENE (Kaguya), which was launched on September 14th, 2007, was the target of VLBI observations over the period November 2007 to June 2009. These observations were made in order to improve the lunar gravity field model, in particular the lower degree coefficients and the model near the limb. Differential VLBI Radio sources, called VRAD instruments, were on-board the subsatellites, Rstar (Okina) and Vstar (Ouna), and the radio signals were observed by the Japanese VERA (VLBI Exploration of Radio Astrometry) network, and an international VLBI network. Multi-frequency and same-beam VLBI techniques were utilized and were essential aspects of the successful observing program. Multi-frequency VLBI was employed in order to improve the accuracy of the orbit determination obtained from the phase delay from the narrow-band satellite signals, while the same-beam VLBI method was used to resolve the cycle ambiguity which is inherent in the multi-frequency VLBI method. The observations were made at three S-band frequencies (2212, 2218 and 2287 MHz), and one X-band frequency (8456 MHz). We have succeeded in correlating the recorded signals from Okina/Ouna, and we obtained phase delays with an accuracy of several pico-seconds at S-band. 相似文献