15results about How to "Reduced insulation requirements" patented technology

The invention discloses an adjustable wide-adaptation MOSFET turn-off gate drive circuit and a drive method, and relates to the field of power electronics, and the drive circuit matches parasitic parameters of a to-be-controlled power MOSFET through parameter configuration so as to improve the applicability. In the turn-off process of the to-be-controlled power MOSFET, the circuit controls the grid voltage to be rapidly decreased at the stage higher than the Miller platform, to be kept at the Miller platform voltage during the Miller platform, to be linearly decreased at the stage from the Miller platform to the threshold voltage, and to be rapidly decreased below the threshold voltage. Through continuous fine control of grid voltage, drain-source side voltage and current track regulation and control are realized. The problems that according to an existing turn-off driving circuit, grid voltage is difficult to finely regulate and control in the turn-off process of a power MOSFET device, voltage and current tracks on the drain side and the source side of the power MOSFET cannot be finely regulated and controlled independently, the targets of low voltage overshoot and low turn-off loss are difficult to meet in the turn-off process at the same time, limited application of the power MOSFET device is difficult to achieve, and the turn-off efficiency of the power MOSFET device is low are solved. And the high power density requirement of the power electronic device is difficult to meet.

The invention discloses a portable X-ray machine for measuring osteoporosis, and relates to the technical field of medical equipment.The X-ray machine adopts 18-26 V wide-range low-voltage power supply, primary boosting is performed through a full-bridge inverter circuit and a high-voltage transformer, secondary boosting is performed through a single-side CW voltage doubling rectifying circuit, the output voltage ranges from 30 kV to 80 kV, and the tube current ranges from 0.1 mA to 1 mA. A pseudo dual-energy imaging technology is introduced, low-energy and high-energy X-rays are used for imaging respectively, artifacts are reduced through continuous multi-image taking and contrast synthesis, and the imaging quality is improved. And the overexposure risk of the CCD camera is reduced by adopting an accurate dose control and delayed exposure technology. And a glue sealing insulation design and a split type structure are adopted, so that the equipment volume is reduced, and the portability is improved. Through integration of multiple technologies, the portable X-ray machine which is efficient, safe, capable of reducing measurement errors and radiation cost is provided, and the portable X-ray machine is suitable for osteoporosis detection.

The invention belongs to the technical field of wind power generation, and particularly provides a semi-direct-drive direct-current type wind turbine generator based on a multi-winding transformer and a control method.The wind turbine generator comprises an impeller and the multi-winding transformer, and the impeller is connected with a wind driven generator through a gearbox; the output end of the wind driven generator is connected with a primary winding of the multi-winding transformer, and each secondary three-phase winding of the multi-winding transformer is connected with an electric energy conversion unit through a three-phase alternating-current circuit breaker; the anode output end of each electric energy conversion unit is used as a first electrical interface of the electric energy conversion unit after passing through a direct current circuit breaker; the cathode output end of each electric energy conversion unit passes through a direct current circuit breaker and then is used as a second electrical interface of the electric energy conversion unit; a bypass switch is connected between the first electrical interface and the second electrical interface of the same electric energy conversion unit; the output ends of the electric energy conversion units are connected in series. No circulating current problem exists, and the output voltage grade of the wind turbine generator is improved.

This invention discloses an inertia-adjustable grid-connected device and control method for reducing motor-to-ground voltage. The device comprises an even number of motor grid-connected interface devices connected in series between the positive and negative buses of a bipolar DC-DC converter. The intermediate node of each even number of motor grid-connected interface devices is grounded to reduce the motor-to-ground voltage. Each motor grid-connected interface device includes a doubly-fed induction generator (DFIG), a first DC / AC converter, a permanent magnet synchronous motor (PMSM), and a second DC / AC converter. The positive terminal of each motor grid-connected interface device is connected to the positive DC side of both the first and second DC / AC converters, and the negative terminal is connected to the negative DC side of both the first and second DC / AC converters. This invention aims to reduce the ground voltage of both the DFIG and PMSM, lower insulation requirements, extend insulation life, and improve the stability and reliability of the electrical system.

The invention provides a power grid supporting type energy storage power station and an operation method, the energy storage power station is connected with an external high-voltage alternating current bus, and the energy storage power station comprises a grid-connected energy storage all-in-one machine, an energy storage direct current converter, a low-voltage direct current bus and voltage strength supporting type equipment; the grid-connected energy storage all-in-one machine is connected to the high-voltage AC bus One side of the energy storage DC converter is connected with the grid-connected energy storage all-in-one machine, and the other side is connected with the low-voltage DC bus The voltage intensity supporting type equipment is connected to the low-voltage direct-current bus; during normal operation of the power grid, the grid-connected energy storage all-in-one machine performs power charging and discharging according to a scheduling instruction; during a power grid fault period, low-voltage direct current provided by the grid-connected energy storage all-in-one machine is converted through the voltage intensity supporting type equipment to provide stable voltage support for the high-voltage alternating current bus; the method can be compatible with an existing energy storage power station, the operation mode of an original power station is not affected, and voltage strength support of a power grid can be achieved.

The invention discloses a gasified hydrogen recovery and pressure relief coupling system for liquid hydrogen storage. The secondary heat exchanger and the primary heat exchanger are respectively provided with a cold side inlet, a cold side outlet, a hot side inlet and a hot side outlet; a hydrogen and air inlet and a tail gas outlet are formed in the auxiliary power device; a hydrogen and diluent gas inlet and a mixed gas outlet are formed in the mixed gas cylinder; a first liquid hydrogen pump in the liquid hydrogen storage tank is connected with the power device through a first one-way valve; a gas hydrogen outlet of the liquid hydrogen storage tank is connected with a hydrogen inlet of the mixed gas cylinder and an inlet of the hydrogen compressor, an outlet of the hydrogen compressor is connected with a cold side inlet of the secondary heat exchanger, and a cold side outlet of the secondary heat exchanger is connected with a hydrogen inlet of the auxiliary power device. An outlet of the air compressor is connected with a cold side inlet of the primary heat exchanger, and a cold side outlet of the primary heat exchanger is connected with an air inlet of the auxiliary power device. According to the liquid hydrogen storage tank, the situation that evaporation gas hydrogen in the liquid hydrogen storage tank is directly discharged to cause aircraft energy waste can be avoided, and meanwhile redundant evaporation gas hydrogen can be safely and reliably discharged to the external environment.

The utility model belongs to gas -cooker technical field discloses a kind of commercial gas -cooker of external low-voltage power supply, this gas -cooker is converted into 24V direct current safety very low voltage by using the power adapter of external convertible voltage, realizes the safe work of gas -cooker;The gas -cooker includes cooktop main body, gas system (including gas valve, igniter etc.), safety control system and the 24V low-voltage wiring harness of connecting each component.The utility model removes the 220V high-voltage line and connecting point of traditional gas -cooker through cookware interior completely, fundamentally eliminates electric shock accident and high-voltage short-circuit fire risk caused by internal line aging, breakage, maintenance error touch.

This invention discloses a MOSFET-based isolated drive circuit system that is easy to control, comprising: an input voltage regulator circuit, a transformer drive circuit, a transformer secondary rectifier and filter circuit, a drive output, and a negative voltage bootstrap circuit; wherein, the input voltage regulator circuit includes: a linear voltage regulator element, a drive power supply, a feedback network, and a filter capacitor; the input terminal of the linear voltage regulator element is coupled to the drive power supply, the drive power supply input voltage is VIN, and the linear voltage regulator element is connected to ground through the coupled feedback network; the input voltage regulator circuit is used to provide a stable DC input to the transformer drive circuit. This invention separates the secondary winding of the transformer in the auxiliary power supply of traditional technology and places it in a discrete transformer, effectively reducing the insulation requirements of the auxiliary power supply transformer and making it easier to drive more MOSFETs. By driving with high-voltage MOSFETs, the problem of excessive auxiliary power supply windings is effectively solved.

The invention discloses a new energy off-grid operation system and method. The new energy off-grid operation system comprises a large-capacity energy storage system branch, an active / passive filtering system branch, a water electrolysis hydrogen production system branch, a station power system branch and a plurality of new energy alternating current system branches which are respectively connected with a medium-voltage alternating current bus; the plurality of new energy alternating current system branches inject electric energy generated by new energy power generation into a power grid through a medium-voltage alternating current bus, and the new energy alternating current system branches adjust power generation power according to load conditions; each system branch performs energy transmission through a medium-voltage alternating-current bus; the water electrolysis hydrogen production system decomposes water into hydrogen and oxygen through electric energy generated by new energy power generation, and the water electrolysis hydrogen production system adjusts the hydrogen production power by being connected with a medium-voltage alternating-current bus. An active filtering system of the active / passive filtering system branch compensates harmonic waves and reactive power in the power grid, and a passive filtering system filters the harmonic waves; and the station power utilization system provides power for the new energy off-grid operation system.

The present application discloses a phase-shifting transformer, including a Sen-type phase shifter and a three-phase isolation transformer connected to each other; the Sen-type phase shifter is used to provide a series compensation voltage for a transmission line, including a three-phase main winding and a three-phase secondary winding; the three-phase main winding includes an A-phase main winding, a B-phase main winding and a C-phase main winding; the three-phase secondary winding includes an A-phase secondary winding, a B-phase secondary winding and a C-phase secondary winding; the three-phase main winding adopts a Y-type connection and is grounded through a neutral point. Through the above-mentioned method, the present application reduces the number of three-phase isolation transformers required; and increases the adjustment range of power flow and phase shift angle; reduces the insulation requirements for the Sen-type phase shifter, making the phase-shifting transformer more suitable for high-voltage power systems.

The present invention discloses a single-bipolar conversion high-voltage large-capacity DC transformer and a control method thereof, including: a unipolar primary side, a bipolar secondary side and an AC unit, wherein the AC unit is connected between the unipolar primary side and the bipolar secondary side. It also includes a single shift control strategy, a sub-module capacitor voltage balancing control strategy, and a DC bias suppression strategy. The AC link of the present invention reduces the cost of the entire system and can achieve bipolar operation. The voltage matching ratio can be 1 / 2, which reduces the insulation requirements of medium and high frequency isolation transformers. The introduction shift angle of the drive signal between the upper and lower bridge arms of the unipolar primary side can also be used to actively inject DC into the primary side of the AC transformer to reduce the time when the DC bias phenomenon occurs.

The invention discloses a powder column coating agent and a coating method for an aerosol fire extinguishing agent. The powder column coating agent is prepared by mixing high temperature resistant silicone oil, an inorganic flame retardant and a platinum-containing catalyst. The powder column coating agent is tightly coated on the surface of the powder column of the aerosol fire extinguishing agent, so as to enhance the shock resistance of the powder column and reduce the damage rate caused by storage and transportation. Meanwhile, the powder column coating agent can also block the combustion heat, reduce the risk of leaping fire and deflagration of the powder column, reduce the heat insulation requirements for the fire extinguishing device and improve the safety of the operators; meanwhile, the powder column can be ensured to burn in an orderly manner and continuously generate a fire extinguishing aerosol for fire extinguishing, so as to avoid explosion accidents caused by the fire extinguishing device being unable to withstand the pressure caused by a large amount of gas generated by the deflagration, thereby improving the safety of fire extinguishing.

The present disclosure relates to a converter for transferring power from a medium voltage side to a low voltage side, comprising: a medium voltage unit on the medium voltage side, comprising a DC / AC unit having a medium voltage AC terminal; a low-voltage unit located at the low-voltage side and configured to generate a low-voltage direct-current voltage from a low-voltage alternating-current voltage at the low-voltage alternating-current terminal; a first transformer unit configured to generate a low-voltage AC voltage at the low-voltage AC terminal from a medium-voltage AC voltage at the medium-voltage AC terminal; a second transformer unit configured to generate an auxiliary AC supply voltage at one or more supply terminals of the second transformer unit from a medium voltage AC voltage at a medium voltage AC terminal; and an auxiliary power supply circuit configured to provide an auxiliary power supply to one or more components of the medium voltage unit based at least in part on an auxiliary AC power supply voltage at the one or more power supply terminals. The invention further relates to a corresponding method for operating the converter.

The utility model discloses a weather resistant charging cable and charging pile, charging cable includes: by power line core, control line core, ground wire, auxiliary power cord and return flow pipe and is twisted into the cable core and the sheath of cladding in the cable core outside, the outside of power line core's central conductor is equipped with a cooling pipe, and the medium flow channel is formed between its inner wall and central conductor, and the medium flow channel and return flow pipe are all used for passing into cooling medium and the flow direction of cooling medium in the medium flow channel and return flow pipe is opposite, and the central conductor is twisted into by several conductor strands, and each conductor strand is twisted into by several monofilament conductors, and the monofilament conductor is composed of metal conductor and insulating coating coated on the outside surface of metal conductor. Return flow pipe and the power line core with the outside cooling pipe are all provided with 2. The utility model neither influences the heat dissipation performance of conductor itself, and can reduce the insulating property requirement of cooling medium in medium flow channel, improves the safety in the use process.

The invention discloses an adjustable wide-adaptation MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) opening gate driving circuit and a driving method, and relates to the field of power According to the circuit, drain-source side information of the power MOSFET to be controlled is not introduced in design, and drain-source voltage and current track regulation and control in the opening process of the power MOSFET to be controlled are realized only by finely controlling grid voltage of the power MOSFET to be controlled. According to the circuit, parasitic parameters of the to-be-controlled power MOSFET are matched through parameter configuration so as to improve the applicability, and in the opening process of the to-be-controlled power MOSFET, the voltage rising slope of the grid voltage in the stage of being higher than the threshold voltage is regulated and controlled, so that drain-source voltage and current track regulation and control are achieved, and the reliability of the power MOSFET is improved. The electromagnetic noise generated by the drain-source current in the reverse recovery stage in the switching-on process is regulated and controlled according to the requirements of the power electronic device; the problems that an existing power MOSFET drive circuit is difficult to finely and continuously regulate and control grid voltage in the turn-on process, drain-source voltage and current cannot meet low electromagnetic interference and low loss at the same time in the turn-on process, and the requirement for high power density of a power electronic device is difficult to meet are solved.