298 results about "DC block" patented technology

High voltage direct current systems to connect direct current energy sources to an alternating current system. In one aspect, a system includes a plurality of direct current modules having variable direct current inputs; an inverter; and a direct current bus to connect the direct current modules to the inverter, where the bus is configured to operate at a nominal voltage higher than 100 volts and to operate within 10 percent of the nominal operating voltage.

A converter has a transformer with primary and secondary windings each having n coils in a series-series arrangement connected to primary and secondary sides. The primary side has n primary legs each having a top switch and a bottom switch and connected to the primary winding therebetween. The secondary side has n secondary legs, each secondary leg has a synchronous rectifier switch and an output filter inductor connected to the secondary winding therebetween. A complimentary control for the primary side comprising a gate driver transformer with primary winding in series with a DC blocking capacitor connected to a drain and a source of the top switch of each primary leg, and a gate drive transformer, for each primary leg, with secondary winding containing a leakage inductor and in series with a DC blocking capacitor and a damping resistor connected to gate and source of the secondary side synchronous rectifier.

A surge protection device is disclosed that includes an input path for receiving an rf signal, dc power, and a surge, an output path for propagating the rf signal, and a dc blocking device coupled in series between the input path and the output path. The surge protection device also includes a first inductor coupled to the input path for isolating the rf signal and providing a path for the dc power, a gas tube coupled to the first inductor for routing a portion of the surge to a ground plane, a second inductor coupled to the first inductor for providing a path for the dc power, and a metal oxide varistor coupled to the second inductor for routing a portion of the surge to the ground plane. Furthermore, the surge protection device includes a third inductor coupled to the second inductor for providing a path for the dc power, a diode coupled to the third inductor for routing a portion of the surge to the ground plane, and a fourth inductor coupled to the third inductor for providing a path for the dc power to the output path.

The invention provides a method for defending periodic commutation failures of a one-tower double-circuit DC transmission system. The method comprises the following steps that (I) an inverter station determines a descent rate of voltage amplitude values according to instantaneous values of grid-side three-phase AC voltages; (II) changes of grid-side voltages are judged by using a sine and cosine component detecting method and a zero-order voltage method; (III) a turn-off angle added value and a turn-off angle returned time constant are determined by using a turn-off angle logic method, and a trigger angle is reduced through a turn-off angle controller; (IV) a rectification station puts instantaneous current control into a commutation failure recovery process. The method for defending the periodic commutation failures of the one-tower double-circuit DC transmission system can effectively prevent periodic commutation failures from occurring to a DC transmission system, and DC blocking accidents are prevented from occurring.

A surge protection device is disclosed that includes a conductor for receiving an rf signal and a dc current, a first shield having a lumen configured to accommodate at least a portion of the conductor, and a second shield having a lumen configured to accommodate the first shield so that a portion of the first shield is positioned within the lumen of the second shield. The surge protection device further includes a dc blocking device, coupled to the conductor, for attenuating the dc current, a device, coupled to the conductor, for diverting the dc current to the second shield, and a dielectric disposed between the first shield and the second shield for preventing the dc current from traveling from the second shield to the first shield.

The mixer circuit is a singled ended input to a double balanced high dynamic range mixer with only two base-emitter junctions across the supply. It provides for the use of bondwires to off chip ground as DC block and DC feed elements. The single ended input and differential output balanced mixer is well suited for the input stage of an integrated radio receiver—off chip circuitry is usually single ended, but on chip circuits are usually differential. No off chip differential RF circuits or baluns are required which reduces off chip component count and improves radio performance. The mixer circuit has lower LO drive requirements because of the DC coupled LO port. This results in better radio performance and a smaller die area because of the DC coupled IF port.

This invention provides a voltage tunable filter comprising an input connection point, an output connection point, and at least one circuit branch electrically coupled to the input connection point and the output connection point and including a voltage tunable dielectric varactor electrically connected to an inductor. The voltage tunable filter can be one of a low-pass, high-pass, band-pass, or band-stop filter. The varactor can include built-in DC blocking capacitors.

This invention discloses a bi-directional air intake pulse tube refrigerator, which contains compressor, heat exchanger at heat end of heat regenerator, cold heat, pulse tube, pulse tube heat end exchanger, small hole valve, air reservoir, corrugated pipe dc block structure in heat end of pulse tube, and capillary set between air inlet of heat regenerator and heat end of pulse tube. Said invention eliminates the influence of dc to refrigeration temperature and quantity, and operation stability.

The invention discloses a method for testing performance of different types of partial discharge detector mainframes based on analog voltage signal injection. A function generator with adjustable output frequency of 0-3.5 GHz and an adjustable output amplitude of 0-10 V is adopted in the method disclosed by the invention, and equivalent analog voltage signals generated by the function generator and based on partial discharge waveforms actually tested by a pulse current partial discharge detection sensor, an ultrasonic partial discharge detection sensor and an ultrahigh frequency partial discharge detection sensor are correspondingly and directly injected into the mainframes of a pulse current partial discharge detector, an ultrasonic partial discharge detector and an ultrahigh frequency partial discharge detector or through DC blocking elements with frequency bands of 10 kHz to 10 MHz. The method disclosed by the invention has the excellent advantages that the testing method is universal and standard, the testing result is reproducible and quantifiable, the range of application of testing objects is wide, the testing contents are comprehensive, and the like.

A radio frequency (RF) switch includes a common port, a first port, and a second port, a first semiconductor switching element disposed in a first RF pathway between the common port and the first port, a second semiconductor switching element disposed in a second RF pathway between the common port and the second port, a first pair of direct current (DC) blocking capacitors disposed to isolate the first semiconductor switching element in the first RF pathway, and a second pair of DC blocking capacitors disposed to isolate the second semiconductor switching element in the second RF pathway. The respective pairs of DC blocking capacitors allow for different bias voltages to be applied to the respective RF pathways. A charge-discharge circuit may also be employed to decrease transient switching time of the RF switch.

A radio frequency device and a wireless communication device. The radio frequency device contains a grounding assembly used for providing ground connection, an antenna which contains a radiator, a signal feed-in assembly for transmitting a radio-frequency signal to the radiator so as to transmit the radio-frequency signal through the radiator and a ground terminal for coupling the grounding assembly, a capacitive sensing assembly for sensing an environmental capacitance value within a specific range through the radiator, a first DC blocking assembly for blocking a DC signal path from a ground terminal of the antenna to the grounding assembly, a second DC blocking assembly for blocking a DC signal path from the radiator to the signal feed-in assembly of the antenna, and a high-frequency blocking assembly which is electrically connected between the radiator and the capacitive sensing assembly and is used for blocking a high-frequency signal path from the radiator to the capacitive sensing assembly. According to the invention, radiant efficiency is not influenced, design and production costs can be reduced, and it is beneficial to parts management. The radio-frequency device has characteristics of small size, high efficiency, high environmental suitability and low interference.

A power utilization information acquisition terminal detecting system comprises terminal conveying device and a detecting device. The terminal conveying device comprises a conveying line, a tooling plate, a jacking transplant, a bar-code scanner, a PLC (programmable logic controller) control system, a first lifter, a second lifter, a driving mechanism and a multilayer detecting bin. The detecting device comprises an automatic pressure jointing mechanism and terminal test equipment which are electrically connected, the terminal test equipment comprises a computer, a control box, a standard scale, a scale position controlling and testing module, a multifunctional tester, a pulse direct-current module, a grounded phase loss testing module, a carrier wave switching module, a carrier save attenuating module, a timer and a power source control module. By the aid of the power utilization information acquisition terminal detecting system, automatic conveying functions of three terminals can be realized, full automatic detecting function of the terminals can be realized, parallel tests to a plurality of centralized meter reading terminals and collector carrier channels can be realized with only one set of power source.

The invention discloses a coordination control and parameter optimization method for a multi-loop DC frequency limit controller. The coordination control and parameter optimization method adopts an online self-adaptive method, balances power fluctuations under a DC blocking fault of a multi-direct-current sending-end system through coordination and cooperation of a frequency limit controller of a multi-loop DC power transmission system, and improves stability of system frequency. The coordination control method for the multi-loop DC frequency limit controller can be applied to a power system dispatching control center. Compared with the prior art, the coordination control and parameter optimization method for the multi-loop DC frequency limit controller can exert the promotion effect of the multi-loop DC frequency limit controller on frequency stability during the system failure more effectively, has higher self-adaptive capability for power system operation methods, and has more effective and flexible control method.

A surge-protected coaxial termination includes a metallic outer body, a center conductor extending through a central bore of the outer body, and a spark gap created therebetween to discharge high-voltage power surges. A pair of dielectric support insulators support the center conductor on opposite sides of the spark gap. High impedance inductive zones surround the spark gap to form a T-network low pass filter that nullifies the additional capacitance of the spark gap. An axial, carbon composition resistor is disposed inside the outer body, and inside the dielectric insulator to absorb the RF signal, and prevent its reflection. The resistor extends co-axially with the center conductor, and one end of the resistor is electrically coupled thereto. A blocking chip capacitor extends radially from the opposite end of the resistor to the grounded outer body. The opposing second end of the resistive component may protrude from the metallic outer body and related dielectric material; the DC blocking capacitor preferably extends radially between the second end of the resistive component and the metallic outer body, or to a grounding post secured thereto.

The invention discloses a direct current magnetic leakage detecting system based on a triggered acquisition mode. The direct current magnetic leakage detecting system comprises a sensor array, a DC-block, an amplifying circuit, a filtering circuit, a triggering circuit, an acquisition card, and an industrial personal computer which are in serial connection sequentially, and also comprises a displacement sensor and a mileage encoder which are in serial connection with the triggering circuit sequentially, wherein the sensor array is provided with a 48-channel hall sensor, and every 16 channels are separately arranged in a radial routing inspection direction BX, a lateral direction BY and a direction BZ perpendicular to the surface of each steel rail; the acquisition card adopts a triggered acquisition mode, and a trigger signal of the acquisition card is provided by the triggering circuit; the triggering circuit is in series connection between the acquisition card and the filtering circuit, and performs threshold judging treatment on a 48-channel detecting voltage signal; the displacement sensor can measure a lift-off value between the sensor array and the surface of the measured steel rail; and the mileage encoder can acquire the routing inspection mileage of the railway steel rails. According to the direct current magnetic leakage detecting system disclosed by the invention, defect magnetic leakage detection can be performed under the condition with different routing inspection speeds, data is not liable to lose, the routing inspection mileage can be acquired and defects can be efficiently positioned.

A low-frequency band suppression enhanced anti-reversal power system stabilizer is presented by the invention. Currently the widely used PSS2B power system stabilizer needs lead elements above Order 2 to meet the phase compensation requirement of DC blocking signal of active power, thus quickly increasing high-frequency band gain, restricting allowable total setting gain of PSS, limiting low-band gain and reducing low-frequency band suppression ability of power system stabilizer. The invention will add generator speed signal ω (which is treated by DC blocking element and corrected by parallel proportional differential PD) and active power signal P_e (which is treated by DC blocking element and gained by gain factor K_s3) to get equivalent synthetic mechanical power of power system stabilizer. The actual active power signal gained by gain factor K_S1 can meet the requirement of phase compensation through Order 1 lead and lag elements, thus increasing allowable total setting gain of PSS and improving the ability of low-frequency band oscillation suppression.