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Небесная энциклопедия

Космические корабли и станции, автоматические КА и методы их проектирования, бортовые комплексы управления, системы и средства жизнеобеспечения, особенности технологии производства ракетно-космических систем

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Мониторинг СМИ и социальных сетей. Сканирование интернета, новостных сайтов, специализированных контентных площадок на базе мессенджеров. Гибкие настройки фильтров и первоначальных источников.

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Применить Всего найдено 8. Отображено 8.
13-10-2010 дата публикации

Determination method of network side harmonic current of high-voltage direct current power transmission system

Номер: CN0101860037A
Принадлежит:

The invention discloses a determination method of network side harmonic current of a high-voltage direct current power transmission system. The determination method comprises the following steps: if the harmonic current voltage at a direct current power transmission line inlet is zero, decoupling and equalizing a rectifying side and an inverting side into a plurality of independent six-pulse moving bridge units; dividing a work period of the six-pulse moving bridge units into six phase converting sections and six non-phase converting sections; calculating a phase converting overlapping angle of each phase converting section; equalizing a current converter into a harmonic current voltage source containing internal resistance; calculating the direct current side harmonic current according to the concrete forms of a smoothing reactor and a direct current filter; obtaining valve side harmonic current according to an equivalent circuit of the current converter; and converting the valve side ...

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02-11-2011 дата публикации

Hybrid DC (direct current) electric power transmission system

Номер: CN0102231520A
Принадлежит:

The invention discloses a hybrid DC (direct current) electric power transmission system comprising a passive filter, a rectifier converter transformer, a thyristor converter, a flat wave reactor, a DC electric power line, a multi-level converter and an inverse converter transformer. A twelve-pulse bridge converter based on a thyristor is arranged at a sending-end rectifier side, and a modularized multi-level converter is arranged at a receiving-end inverter side, thus eliminating the phase conversion failure of the traditional DC electric power transmission system fundamentally and being suitable for supplying power for multi-DC droppoint areas, passive networks or weak alternating current systems and other occasions. Compared with a light-type high-voltage DC electric transmission system, the hybrid DC electric power transmission system provided by the invention has the advantages that the number of expensive full-control devices is greatly decreased, the cost is reduced, the loss is reduced ...

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06-10-2010 дата публикации

Circulating-current restraining method for three-phase modular multilevel convertor

Номер: CN0101854061A
Принадлежит:

The invention discloses a circulating-current restraining method for a three-phase modular multilevel convertor. The method comprises the following steps of: processing detected bridge current by utilizing fundamental frequency-doubled rotating coordinates transform based on negative sequences, and then performing signal processing and feedforward compensation link so as to acquire an additional control signal used for restraining circulating current; subtracting the additional control signal from a half of a DC voltage value, superposing an output voltage reference signal on the AC side of the existing converter to acquire a bridge voltage reference signal, and performing pulse width modulation to acquire trigger pulses of various bridges of the converter to ensure that the converter outputs corresponding voltage. The circulating-current restraining method can restrain the circulating current in the converter in a low level under the condition of not increasing the inductance of the bridges ...

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25-04-2012 дата публикации

Circulating-current restraining method for three-phase modular multilevel convertor

Номер: CN0101854061B
Принадлежит:

The invention discloses a circulating-current restraining method for a three-phase modular multilevel convertor. The method comprises the following steps of: processing detected bridge current by utilizing fundamental frequency-doubled rotating coordinates transform based on negative sequences, and then performing signal processing and feedforward compensation link so as to acquire an additional control signal used for restraining circulating current; subtracting the additional control signal from a half of a DC voltage value, superposing an output voltage reference signal on the AC side of the existing converter to acquire a bridge voltage reference signal, and performing pulse width modulation to acquire trigger pulses of various bridges of the converter to ensure that the converter outputs corresponding voltage. The circulating-current restraining method can restrain the circulating current in the converter in a low level under the condition of not increasing the inductance of the bridges ...

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04-07-2012 дата публикации

Determination method of high voltage direct current converter commutation overlap angle

Номер: CN0101834437B
Принадлежит:

The invention discloses a determination method of a high voltage direct current converter commutation overlap angle, aiming to solve the problem that a traditional method for calculating a commutation overlap angle can not take nonideal factors including background harmonics into consider to cause poor design performance of a wave filter. The method comprises the following steps of dividing the working period of a converter into six commutation sections and six non-commutation sections; establishing a differential equation to each commutation section by considering factors such as background harmonic interference, asymmetric fundamental voltage, asymmetric converter trigger angle distances, commutation impedance deviation and the like; and accurately calculating the commutation overlap angle. The invention efficiently enhances the calculation efficiency when ensuring the accuracy and can enhance the design quality of an alternating current converter.

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04-08-2010 дата публикации

Method for starting three-phase modular multilevel inverter without auxiliary DC power supply

Номер: CN0101795057A
Принадлежит:

The invention discloses a method for charging and starting a three-phase modular multilevel inverter in a self-excitation way under the condition of no need of an auxiliary DC power supply. In the method, by adopting interphase currents generated by line voltages of an AC system among converter bridge arms, the process of charging capacitors of all the submodules on the bridge arms is completed by controlling switching on and switching off an upper electronic power switch and a lower electronic power switch in the submodules of all the bridge arms when current directions of the bridge arms and capacitor voltages of all the submodules are detected; and all the bridge arms can be simultaneously charged, so that the three-phase modular multilevel inverter can be quickly and normally started in the self-excitation way.

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15-09-2010 дата публикации

Determination method of high voltage direct current converter commutation overlap angle

Номер: CN0101834437A
Принадлежит:

The invention discloses a determination method of a high voltage direct current converter commutation overlap angle, aiming to solve the problem that a traditional method for calculating a commutation overlap angle can not take nonideal factors including background harmonics into consider to cause poor design performance of a wave filter. The method comprises the following steps of dividing the working period of a converter into six commutation sections and six non-commutation sections; establishing a differential equation to each commutation section by considering factors such as background harmonic interference, asymmetric fundamental voltage, asymmetric converter trigger angle distances, commutation impedance deviation and the like; and accurately calculating the commutation overlap angle. The invention efficiently enhances the calculation efficiency when ensuring the accuracy and can enhance the design quality of an alternating current converter.

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27-06-2012 дата публикации

Method for starting three-phase modular multilevel inverter without auxiliary DC power supply

Номер: CN0101795057B
Принадлежит:

The invention discloses a method for charging and starting a three-phase modular multilevel inverter in a self-excitation way under the condition of no need of an auxiliary DC power supply. In the method, by adopting interphase currents generated by line voltages of an AC system among converter bridge arms, the process of charging capacitors of all the submodules on the bridge arms is completed by controlling switching on and switching off an upper electronic power switch and a lower electronic power switch in the submodules of all the bridge arms when current directions of the bridge arms and capacitor voltages of all the submodules are detected; and all the bridge arms can be simultaneously charged, so that the three-phase modular multilevel inverter can be quickly and normally started in the self-excitation way.

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