115 results about "Back-to-back connection" patented technology

A developing mechanism for the solar cell said board of spaceship is composed of the developable torsional spring, the nylon band for binding the foldable solar cell said board, the fusing unit for cutting off the nylonb and to develop said solar cell said board, and the developed solar cell said board locating mechanism consisting of the automatic extensible locating pin and its locating tube, which are respectively arranged on adjacent solar cell board.

The invention relates to a turn-off device-based mobile power transmission device, which comprises two groups of independent high-voltage converter stations. The two groups of independent high-voltage converter stations are combined together through parallel connection on a DC side in a back-to-back connection mode and are taken as a transmitting end and a receiving end for DC power transmission respectively, wherein the transmitting end is connected with a three-phase AC output terminal of an electric network; and the receiving end can be connected with an active electric network or a passive electric network according to the requirements of the power transmission. The power transmission method adopts a two-layer control mode of upper layer control and lower layer unit control, wherein the upper layer control mainly coordinates control targets of power units of a plurality of converters and system protection, and the lower layer unit control performs real-time control and protection on the power units. The mobile power transmission device has the characteristics of small size, high efficiency, flexible control and the like, improves the operating range and the utilization ratio of the device and also greatly improves the quality of electric energy.

The invention discloses a control method for an alternating current solid-state power switch. The method comprises two solid-state switch MOSFETs which are in back-to-back connection, a load current polarity sampling circuit, a line voltage polarity sampling circuit, a D-type trigger, a logic gate circuit and an isolated power supply; and the control method is characterized by comprising the following steps: detecting the changes of the voltage polarity or the current polarity of a load circuit; latching opening/closing control signals by the D-type trigger; and switching on or off the two solid-state switches so as to switch on or off a power supply circuit of an alternating current load. The control method for the alternating current solid-state power switch has the advantages of achieving the switch-on and switch-off controls of an alternating current electric load and having the characteristics of one triggering, natural zero-crossing switch-on and switch-off, no generation of electromagnetic interferences, and low switch power consumption.

The present invention provides permutation instructions which can be used in software executed in a programmable processor for solving permutation problems in cryptography, multimedia and other applications. The permute instructions are based on a Benes network comprising two butterfly networks of the same size connected back-to-back. Intermediate sequences of bits are defined that an initial sequence of bits from a source register are transformed into. Each intermediate sequence of bits is used as input to a subsequent permutation instruction. Permutation instructions are determined for permitting the initial source sequence of bits into one or more intermediate sequence of bits until a desired sequence is obtained. The intermediate sequences of bits are determined by configuration bits. The permutation instructions form a permutation instruction sequence of at least one instruction. At most 21 gr/m permutation instructions are used in the permutation instruction sequence, where r is the number of k-bit subwords to be permuted, and m is the number of network stages executed in one instruction. The permutation instructions can be used to permute k-bit subwords packed into an n-bit word, where k can be 1, 2, . . . , or n bits, and k*r=n.

The invention discloses an MMC-UPFC-based three-phase imbalance governance system and method of a power transmission line. The system comprises a modular multilevel-unified power flow controller MMC-UPFC, wherein the MMC-UPFC comprises a parallel side converter and a series side converter which are in back-to-back connection and share a same DC bus; the parallel side converter is connected with an AC side of a power grid through a parallel transformer; and the series side converter is connected with a power transmission line side through a series transformer. The system and the method disclosed by the invention have the beneficial effects that control on power flow of the power transmission line can be achieved while a three-phase imbalance problem of the power transmission line is solved, the problems of a light load and an overload of the power transmission line can be solved; the application function is expanded; and safe, economic and stable operation of a power system is ensured.

The invention provides a flexible direct current power transmission converter performance testing platform and a control method thereof. The direct current side of a first modularized multi-level converter and the direct current side of a second modularized multi-level converter are connected in a back-to-back mode, and three phases of the alternating current side of the first modularized multi-level converter are connected with three phases of the alternating current side of the second modularized multi-level converter correspondingly, so that a power circulation pathway is formed; a test power source is in parallel connection with the direct current side of the first modularized multi-level converter and the direct current side of the second modularized multi-level converter and provides loss power for steady-state operation testing; a short circuit generator is in parallel connection with the direct current side of the first modularized multi-level converter and the direct current side of the second modularized multi-level converter. According to the testing platform and the control method thereof, the requirement for power grid capacity is low; meanwhile, the direct current side power supply mode is adopted in the testing platform, and therefore the single test power source is adopted for the whole platform. With regard to test items of the short circuit and over-current turn-off required by IEC standards, due to the fact that the basic structure of the platform is basically the same with that of practical engineering, the short circuit test and the over-current turn-off test can be set through the platform according to double-pole short-circuit faults in a practical flexible direct current power transmission system.

A steel joist member for use in supporting floor structures giving great strength and convenience and improved acoustical performance having a web defining side edges and an axis, a flange on at least one side edge, openings through said web at spaced intervals therealong, having rounded ends and parallel linear sides, portions of said web displaced from said opening remaining attached integrally to the web by bend lines formed on the linear sides of the opening along axes parallel to the web axis, and forming reinforcing channels alongside the opposite sides of the opening. Also disclosed is a composite joist member made up of two such members joined together back to back with their openings in registration creating an H shape or an I shape. Also disclosed is a rim member for supporting the composite joists to form a floor structure. Also disclosed is a method of making such a floor joist member. Also disclosed is a floor panel system wherein floor panels can be prefabricated in a factory and transported to a construction site ready for installation in a building.

The invention discloses a ship shaft generator system and a control method thereof, so as to solve the problems that seamless switching between power generation voltage and a frequency of brushless doubly-fed machine stator and voltage and frequency of a ship power station can not be realized in the prior art and the system can not operate stably when the ship load changes suddenly. The system mainly comprises a grid-connected device (11), an input filter unit (12), a grid-side power unit (13), a machine-side power unit (14), an output reactor (15) and a control system (17), wherein the grid-connected device is connected with the grid-side power unit via the input filter unit; the machine-side power unit is connected with a control winding (3) via the output reactor; and the grid-side power unit and the machine-side power unit are in back-to-back connection. An industrial PC (18) acquires current, voltage, rotation speed and busbar voltage of the brushless doubly-fed machine respectively and the ship shaft generator system is stably controlled. The control method of the invention adopts vector control algorithm and can be used in the ship shaft generator system.

A configuration of vector units, digital circuitry and associated instructions is disclosed for the parallel processing of multiple Viterbi decoder butterflies on a programmable digital signal processor (DSP) that is based on single-instruction-multiple-data (SIMD) principles and provides indirect access to vector elements. The disclosed configuration uses a processor with two vector units and associated registers, where the vector units are connected back to back for processing Viterbi decoder state metrics. Viterbi add instructions increment vectors of state metrics from a first register, performing a desired permutation of state metrics while reading them indirectly through vector pointers, and writing intermediate result vectors to a second register. Viterbi select instructions perform element-wise maximum or minimum operations on vectors from the second register to determine survivor metrics, performing a desired inverse permutation of survivor metrics while writing them back to the first register and recording the corresponding decisions in a shift register for use in a subsequent traceback operation.

The invention discloses a modular multilevel converter (MMC) four-quadrant frequency converter and belongs to the field of electric power and electronics, for solving the problems of capacitive voltage fluctuations existing during low-frequency operation of an MMC, quite large current impact brought by a high-frequency injection method and the like. The MMC four-quadrant frequency converter comprises two MMCs connected in a back-to-back mode, and the two MMCs are a network-side MMC and a machine-side MMC; and the power supply input end of the network-side MMC is connected with an AC power network, the DC bus output end of the network-side MMC is connected with the DC bus input end of the machine-side MMC, and the load output end of the machine-side MMC is connected with a motor type load.

A first motor-actuated expansion valve and a second motor-actuated expansion valve which are connected in parallel with each other in back-to-back connection are provided between an outdoor heat exchanger and an indoor heat exchanger. In the first motor-actuated expansion valve, at the time of non-operation and full closure, when the refrigerant pressure on the indoor heat exchanger side is higher than the refrigerant pressure on the outdoor heat exchanger side by a predetermined value or more, the full closure is released by receiving the refrigerant pressure on the indoor heat exchanger side. In the second motor-actuated expansion valve, at the time of non-operation and full closure, when the refrigerant pressure on the outdoor heat exchanger side is higher than the refrigerant pressure on the indoor heat exchanger side by a predetermined value or more, the full closure is released by receiving the refrigerant pressure on the outdoor heat exchanger side.

One or more on-chip VNCAP or MIMCAP capacitors utilize a variable MOS capacitor to improve the uniform capacitance value of the capacitors. This permits the production of silicon semiconductor chips on which are mounted capacitors having capacitive values that are precisely adjusted to be within a range of between about 1% and 5% of their design value. This optimization can be achieved by the use of a back-to-back connection between a pair of the variable MOS capacitors for DC decoupling. It involves the parallelization of on-chip BEOL capacitance of VNCAP and/or MIMCAP capacitors by the insertion in the FEOL of pairs of back-to-back variable MOS capacitors.

A microphone having: a first bidirectional microphone unit formed by connecting two unidirectional microphone units, each of which has a vibrating section on a front side thereof, back to back; and a second bidirectional microphone unit formed by connecting two unidirectional microphone units, each of which has a vibrating section on a front side thereof, back to back, and a directional axis of the second bidirectional microphone unit is arranged to be shifted by 90 degrees with respect to a directional axis of the first bidirectional microphone unit.

Apparatus for lifting a hollow frame when the apparatus is attached to a hoist, comprising a pair of lifting members each in the form of a bell crank having an upright arm and a lateral arm, extending outwardly from a lower end of the upright arm, outer ends of the lateral arms having flanges for engaging the interior of the frame to be lifted. The lifting members are connected back-to-back by brackets and a central pivot. Suspension chains connect upper ends of the upright arms to a hoist chain such that the suspension chains slope outwardly from the hoist chain to the arms, and so that when the hoist chain applies tension to the suspension chains the upright arms are pulled towards each other while causing the lateral arms to extend and engage with the inside of the hollow frame.

The invention relates to a variable wind generator system of a double convex pole permanent-magnet wind motor and a control method thereof, including a wind mill and a double convex pole permanent-magnet wind motor and two PWM power converters and a controller, wherein the wind mill is connected with the transmission shaft of the double convex pole permanent-magnet wind motor; the stator armature winding terminal of the double convex pole permanent-magnet generator is connected with the PWM power converter at the side of the generator; the AC side of the net side PWM power converter is connected with the electric network; two PWM power converters are connected back to back. The controller at the side of the generator of the PWM power converter includes a current sensor, a rotary encoder and a controller including s SVPWM generator, the input end of which is connected with the current sensor, the rotary encoder, and the PWM power converter is controlled by the output signals of the SVPWM generator.

The invention relates to a four-quadrant three-level power unit. The four-quadrant three-level power unit is characterized in that the four-quadrant three-level power unit comprises three-phase three-level rectifier bridges which are respectively connected to a DC (direct current) bus, equalizing resistances, DC-link capacitor modules and single-phase three-level inverter bridges, wherein the three-phase three-level rectifier bridges and the single-phase three-level inverter bridges are connected back to back, each of the three-phase three-level rectifier bridges includes three phases first bridge arms and each of the three phases first bridge arms includes four power switch tubes, antiparallel follow current power tubes and two clamping modules, and each of the center taps of the clamping modules is connected to each of the center taps of the DC-link capacitor modules. The invention also provides a high-voltage inverter including the four-quadrant three-level power unit. The four-quadrant three-level power unit utilizes the three-level topological structure to enable the output voltage of the power unit to be increased substantially, so that the amount of the power units which are in overall unit series with the high-voltage inverter can be decreased substantially and the overall unit is high in reliability and long in service life.

Duplicate PCI bridge devices are configured for synchronous initializations based on shared initialization signals. A first of the PCI bridge devices is configured to rely on bus arbitration performed by the second PCI bridge device. The first PCI bridge device also is configured for modifying an address of a data transaction received via a PCI bus, and forwarding the data transaction with the modified address to the second PCI bridge device via a link distinct from the PCI bus.

The invention relates to a multi-time-scale mathematical model establishing method of a distributed power flow controller. The method comprises: S1, a parallel-side apparatus of a distributed power flow controller is used as one converter groups including a parallel grid-side three-phase converter equivalent circuit, a parallel harmonic-side single-phase converter equivalent circuit, and a parallel-side common direct-current capacitor equivalent circuit in back-to-back connection; S2, a series-side apparatus of the distributed power flow controller is used as one applied to an alternating-current fundamental wave network equivalent circuit, an alternating-current third harmonic network equivalent circuit, and a series-side direct-current capacitor equivalent circuit simultaneously; S3, according to the principle of a voltage type PWM converter switch cycle average model, a dynamic mathematical model of the distributed power flow controller is established; and S4, a multi-time-scale analysis is carried out on the dynamic mathematical model of the distributed power flow controller by combining a singular perturbation principle and a multi-time-scale mathematical model of the distributed power flow controller is established. Therefore, the multi-time-scale characteristic of the whole power system can be analyzed well. The method is suitable for the order reduction analysis of the power system.

The invention discloses a general adaptive assembly for a large-scale interface and a signal path planning method based on the adaptive assembly. A 32*8 (line*row) row matrix switch and n 8*32 (line*row) line matrix switches are connected in a back-to-back way; common 8 channels serve as analog bus 8 channels, a 32*32n switch network based on an analog bus is formed, the scale of the adaptive assembly is expanded, and the expansion capacity of the adaptive assembly is improved; a matched resistance selecting circuit is arranged in the switch network, a user can be allowed to select resistance access circuits with different resistance values according to testing equipment and the attribute of a load, and impedance matching between an instrument and the load is improved; according to a path planning method based on the general adaptive assembly provided by the invention, a channel with the minimum using frequency is selected during path planning at each time, and the using frequency of a control switch in each channel is balanced, so that the service life of the whole switch network is prolonged.

The invention provides a back-to-back connection method for a new energy vehicle charging pile. The method comprises the steps that a charging gun is inserted into a docking device in a new energy vehicle and automatically switches the docking device to a conductive state from a masked state, the charging gun introduces electric energy into the docking device through a pile body, and an electric storage tank in the new energy vehicle is charged; after charging is completed, the charging gun is pulled out of the docking device and automatically switches the docking device to the masked state from the conductive state, and the charging gun stops charging the new energy vehicle.

The invention provides a back-to-back testing circuit based on a DC/DC converter. The back-to-back testing circuit comprises DC buses, a power supply module and a DC/DC converter module. The DC buses are used for connecting the power supply module and the DC/DC converter module in series. According to the back-to-back testing circuit, a back-to-back connection manner is utilized on a tested member; Supplying of one end DC voltage to the tested member is required. Furthermore voltage grade can be selected according to a relatively low rated DC voltage of the tested member. More importantly, two converters can feed most absorbed electric energy back to a power grid, and the power supply part of the testing circuit only supplies a relatively low output current, thereby greatly reducing capacity and manufacture difficulty of testing equipment, and greatly reducing testing equipment cost and operation cost in testing.

The invention provides an oil pumping rod anti-fouling device and relates to an oil pumping rod anti-fouling device for an oil well. The oil pumping rod anti-fouling device comprises a main body; a channel is formed at the center of the main body; two elastic rubber barrels are arranged inside the main body, are C-shaped and are in back-to-back connection with each other; a through hole is formed at the connecting center of the two elastic rubber barrels, and a center point of the through hole in a horizontal plane is superposed with that of the main body on the same horizontal plane; and the two elastic rubber barrels are hermetically connected with an oil pumping rod.

The invention relates to the technical field of microwave circuits, in particular discloses a multiplier of a left-hand nonlinear transmission line based on Schottky diodes, comprising single-sectionor multi-section left-hand nonlinear transmission line units. An equivalent circuit of the left-hand nonlinear transmission line units comprises variable capacitors connected in series and inductors connected in parallel, wherein a variable capacitor is formed by the back-to-back connection of a pair of Schottky diodes, and blocking capacitors in a traditional left-hand nonlinear transmission lineare replaced by back-to-back diodes in a self-biasing structure. The invention increases the working efficiency of the multiplier, improves the microwave characteristics and simplifies the circuit structure.