3644 results about "High-voltage direct current" patented technology

A system for controlling an electrosurgical generator using a full bridge topology is disclosed. The system includes a high voltage direct current power source which supplies power and a radio frequency output stage which receives power from the high voltage direct current power source and outputs radio frequency energy at a predetermined radio frequency set point. The system also includes one or more sensors which determine one or more parameters of radio frequency energy being applied to tissue and a microprocessor configured to receive one or more parameters and outputs the predetermined radio frequency set point to the radio frequency output stage as a function of one or more of the parameters of radio frequency energy.

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 modular HVDC converter system including a high voltage direct current network, and at least two DC / AC converters being connected in series to the HVDC network. Each of the DC / AC converters is arranged to provide AC to a separate AC load.

A system to collect energy from generation systems such as, for example, wind farms or solar farms with distributed energy-generation equipment. The energy is collected and transmitted to a feed-in site. At the feed-in site, static inverters alone or in combination with pulse width modulation inverters may be used to feed the energy to a power grid. In some other cases, back-to-back static inverters create a high-voltage direct current to feed a transmission line.

The utility model relates to a digitized high voltage direct current power supply, and comprises a main power circuit, a digitized control circuit based on DSP and a control program of host computer based on PC, wherein the main power circuit comprises a three phase rectifying element [1], a soft start element [2], a filter element [3], a resonance inverting element [4], a high frequency and high voltage transformer [5], a doubling circuit [6] and a two-stage voltage divider [7]; the digitized control circuit based on DSP comprises an interface circuit of IPM drive signal, a high voltage feedback element, a resonance overcurrent protection element, a soft start circuit and a serial communication interface circuit. The voltage of power frequency electrical network is converted into DC voltage which is used as busbar voltage by three phase rectification, soft start and filter, and the busbar voltage is converted into 20KHz quasi-sine-wave by the resonance inverting element which is driven by a phase difference computed by the DSP according to feedback signal, and then 0-100Kv AC high voltage is output by the high frequency and high voltage transformer [5] and the doubling circuit [6]. The utility model adopts a host computer as a control device, and outputs the voltage via the control instructions of the DSP, therefore meets the requirements of voltage withstand test of insulation material.

A power electronic converter for use in high voltage direct current power transmission and reactive power compensation comprises a plurality of switching elements interconnecting in use a DC network and one or more AC networks, the plurality of switching elements being controllable in use to facilitate power conversion between the AC and DC networks, wherein in use, the plurality of switching elements are controllable to form one or more short circuits within the power electronic converter so as to define one or more primary current flow paths, the or each primary current flow path including a respective one of the AC networks and the power electronic converter and bypassing the DC network.

The invention relates to a breaker of a direct current system, in particular to a semi-controlled active injection current high voltage direct current breaker and a realization method thereof. The breaker comprises a high speed switch-thyristor module branch, as well as a lightning arrester branch and a bridge circuit which are connected in parallel with the branch, wherein a capacitor-reactor series branch and a resistor-thyristor series branch are connected in parallel and then connected with middle points of two bridge arms of the bridge circuit; and the two ends of a capacitor are connected in parallel with a charging loop. The breaker is based on a direct current breaking principle by the traditional active injection current manner; semi-controlled power electronic devices are added; a high speed mechanical switch is adopted; the advantage of low loss during normal breakover is kept; and bidirectional current can be broken quickly without an arc. The breaker is simple in circuit topological structure, simple and convenient to control, mature in technology, easy to realize, great in current breaking capability, high in withstand voltage level and strong in expansion capability, and the cost is lowered greatly since the number of the adopted power electronic devices is small.

The invention discloses an electrical system for a pure electric vehicle. A positive end bus high-voltage direct current contactor, a negative end bus high-voltage direct current contactor and a high-voltage safety switch are arranged between a battery management system of the electrical system and a driving motor controller; and a key switch is used for controlling low-voltage power supply relays of all electrical parts. When the electric vehicle is stopped to be charged, a vehicle-mounted charger independently supplies power to a low-voltage power supply end of the battery management systemand a high-voltage direct current bus; when the key switch is adjusted to an ON position, all of a vehicle controller, the battery management system and the vehicle-mounted charger have no serious faults, and the negative end bus high-voltage direct current contactor, a precharging high-voltage relay and the positive end bus high-voltage direct current contactor are sequentially closed; and when the key switch is adjusted to a Start position, the electrical system can accept an instruction of a driver to drive the vehicle to run. When the key switch is switched on, an electric power-assisted steering device, an electric air conditioner, a braking power-assisted vacuum pump, an electric pump and an electric cooling fan are all controlled to work, and a low-voltage storage battery is charged through buck DC / DC.

A high-voltage direct-current breaker is composed of an initial current path (1) and a fail current interdicting path (2). The initial current path (1) comprises at least one electric electronic switch module (3) and a mechanical switch (4), and the fail current interdicting path (2) comprises an initial capacitor (C) and a modular switching subunit series connection component (5). The modular switching subunit series connection component (5) is formed by connecting a plurality of sub units (6) in series. When a high-voltage direct-current electric transmission line fails, the opening and closing of a fail electric transmission line can be rapidly achieved.

The invention provides a device, a system and a method for measuring space charges by using an electro-acoustic (PEA) method. The device comprises a first electrode, a second electrode, a first thermostatic source, a second thermostatic source, a high-voltage direct current power supply, a pulse generator and a piezoelectric transducer, wherein the first electrode is used for contacting with one surface of the tested insulation material sample; the second electrode is used for contacting with the other surface of the tested insulation material sample; the first thermostatic source is used forconducting the temperature to the first electrode; the second thermostatic source is used for conducting the temperature to the second electrode; the high-voltage direct current power supply is used for transmitting the high-voltage direct current to the first electrode; the pulse generator is used for transmitting a high-voltage pulse signal to the first electrode; the piezoelectric transducer is used for detecting the acoustic signal of the tested insulation material sample, generated by the functions of the temperature gradient field, the high-voltage electric field and the high-voltage electric pulse, and is used for converting the acoustic signal into an electrical signal to output. The invention is used for measuring the distribution of the space charges in the high-voltage direct current power equipment insulation in the temperature gradient field.

The invention discloses a high-precision bio-compound 3D printing device and a printing method. The high-precision bio-compound 3D printing device comprises a cell printing spraying head and an electrostatic direct writing device which are arranged above a collection platform and are connected with a motion control module, wherein the cell printing spraying head is connected with an ultra-precision injection pump; the electrostatic direct writing device is connected with a reflux heating device; a main unit and a high-voltage direct current power supply are arranged outside an ultra-clean experiment table; the electrostatic direct writing device, the cell printing spraying head and the high-voltage direct current power supply are connected with the main unit. The printing method comprises the following steps: the main unit automatically switches the cell printing spraying head and the electrostatic direct writing device to print a cell-containing gel / biological scaffold / micro-channel compound structure; after the printing of one layer is completed, the cell printing spraying head and the electrostatic direct writing device move a distance equal to the thickness of one layer in the Z-axis direction for printing of the next layer, and repeating till all tissue organs to be printed are completed in printing. The high-precision bio-compound 3D printing device can stably and precisely print compounds of various cells and submicron or nano-level biological scaffolds.

In one embodiment, a current-fed modular multilevel dual active-bridge DC-DC converter suitable for medium voltage direct current (MVDC) grid or high voltage direct current (HVDC) grid integration is described. The DAB modular converter and the current-fed DAB converter are soft-switched modular multilevel dual-active-bridge (DAB) converters having DC fault ride-through capability. In an additional embodiment a voltage-fed isolated modular dual active-bridge DC-DC converter for medium voltage direct current (MVDC) or high voltage direct current (HVDC) grids or systems is described. In specific embodiments, the converters may be coupled to a battery energy storage system (BESS), wherein the BESS comprises split-battery units and the interface of the isolated DC-DC converter connects the split-battery units to the MVDC or HVDC system. The converters can be implemented in single-phase or poly-phase configurations and can be controlled to maintain a desired DC output current under both normal and DC grid fault condition.

A variable speed wind turbine having a doubly fed induction generator (DFIG), includes an exciter machine mechanically coupled to the DFIG and a power converter placed between a rotor of the DFIG and the exciter machine. Thus, the power converter is not directly connected to the grid avoiding the introduction of undesired harmonic distortion and achieving a better power quality fed into the utility grid. Moreover, the variable speed wind turbine includes a power control and a pitch regulation.

The present invention provides a measurement device for the voltage of a high voltage system and an insulation resistance, which comprises a high voltage system direct current voltage sampling module, an insulation resistance sampling module, a signal processing module, a high voltage system isolation module, a primary controller module, a CAN bus interface module and a power supply module. The high voltage system direct current voltage sampling module and the insulation resistance sampling module are connected with a positive end of a high voltage direct current system by sampling resistances R36 and R38, and connected with a negative end of the high voltage direct current system by the sampling resistances R37 and R39. The sampling voltage is directly transmitted to the signal processing module through amplifiers U16A and U17B, and voltage signals U1 and U2 are output. The voltage signals U1 and U2 are isolated after connecting with the high voltage system isolation module, and output signals AD1 and AD2 are directly input an AD converter of the primary controller module. Pins164 and 265 of a primary controller are connected with the CAN bus interface module. A power supplying module is connected with a direct current power supply +9V-+18V which can supply the whole system. The present invention can transmit the measured insulation resistance and the direct current voltage to a CAN bus and can be connected to vehicle systems easily.

The invention relates to high-voltage DC cable insulating material and a preparation method thereof in the technical field of the insulating material. The preparation method is that: 100 weight portions of low-density polyethylene, 0.1-1 weight portion of anti-oxidizer, 0.5-5 weight portions of nano inorganic powder and 0.2-5 weight portions of maleic anhydride are placed into and mixed and compounded in a banbury mixer; the temperature of mixing and compounding is 373K to 378K and the mixing and compounding time is 10 to 15 minutes; 0.1-5 weight portions of cross-linking agent is added into the mixture and is mixed and compounded under the temperature of 373K to 378K for 10 to 15 minutes; then, the high-voltage DC cable insulating material is obtained; wherein, the density of the low-density polyethylene is less than 0.9g / cm<3>. The insulating material of the preparation method can effectively improve the mechanical and electric properties of the high-voltage DC cable, thus avoiding the disadvantage that the environment is polluted and damaged by an oilpaper insulating cable due to the leakage of the insulating oil.

A high voltage direct current (HVDC) converter system includes a line commutated converter (LCC) configured to convert a plurality of AC voltages and currents to a regulated DC voltage of one of positive and negative polarity and a DC current transmitted in only one direction. The HVDC converter system also includes a buck converter configured to convert a plurality of AC voltages and currents to a regulated DC voltage of one of positive and negative polarity and a DC current transmitted in one of two directions. The LCC and the buck converter are coupled in parallel to an AC conduit and are coupled in series to a DC conduit. The HVDC converter system further includes a filtering device coupled in parallel to the buck converter through the AC conduit. The filtering device is configured to inject AC current having at least one harmonic frequency into the AC conduit.

A high voltage direct current (HVDC) converter system includes at least one line commutated converter (LCC) and at least one current controlled converter (CCC). The at least one LCC and the at least one CCC are coupled in parallel to at least one alternating current (AC) conduit and are coupled in series to at least one direct current (DC) conduit. The at least one LCC is configured to convert a plurality of AC voltages and currents to a regulated DC voltage of one of positive and negative polarity and a DC current transmitted in only one direction. The at least one current controlled converter (CCC) is configured to convert a plurality of AC voltages and currents to a regulated DC voltage of one of positive and negative polarity and a DC current transmitted in one of two directions.

The invention relates to a circuit breaker and a realization method thereof, and specifically relates to a mixed high-voltage direct-current circuit breaker and a realization method thereof. The direct-current circuit breaker is based on the principle of secondary current transfer. A main branch is composed of a quick-action mechanical switch and a current transfer module which contains a full-controlled device, which ensures the advantages of low loss and flexible current transfer control in the state of normal conduction. A first current transfer branch is composed of half-controlled device thyristors connected in series, so that the circuit breaker has strong fault flow capacity and breaking capacity, 'zero voltage and zero current' of the mechanical switch can be maintained long enough, and arc-free switching of the mechanical switch is realized. A second current transfer branch is composed of capacitors with pre-charged voltage, an inductor, and series-connected thyristors. After the thyristors of the first current transfer branch are reliably switched off, the capacitors quickly build up direct voltage high enough to resist the system, and an energy absorption circuit limits the voltage of the capacitors. Thus, the size and cost of the capacitors are well controlled.

An air filtration system includable in and for HVAC equipment includes one or more intense field dielectric filter units and a field charging unit retained in a support structure or cabinet by a removable door which includes control circuitry and contactors engageable with corresponding contact members on a filter unit and the field charging unit for supplying high voltage DC potential to the respective units. Each filter unit includes a filter core comprising a stacked array of filter elements formed of dielectric sheets interconnected by elongated spaced apart ribs forming flow passages. The field charging unit and the filter units are removable from the support or cabinet for cleaning or replacement by opening or removing the door. An interlock switch and a field shorting mechanism are actuated during servicing or replacement of the system components.

An apparatus for DC fast charging of an electric vehicle includes an active front end AC-DC converter and an isolated DC-DC converter. The active front end AC-DC converter is adapted to rectify a medium voltage alternating current (AC) from a utility grid to a high voltage direct current (DC). The isolated DC-DC converter is adapted to transform the high voltage DC to a low voltage DC for charging the electric vehicle.

The present invention relates to a no-ozone cleanable electrostatic dust collector which comprises an ionized region, a dust collecting region, a high-voltage alternating current power supply and a high-voltage direct current power supply. The ionized region is arranged above the dust collecting region; the high-voltage alternating current power supply is connected with the ionized region; the high-voltage direct current power supply is connected with the dust collecting region; adjacent ionized electrode plates are two different electrodes; dust collecting electrode plates are fixed on an outer frame by the block position; and the interphase dust collecting electrode plates are connected by conductive material, so that the adjacent dust collecting electrode plates are two different electrodes. The no-ozone cleanable electrostatic dust collector can collect dust efficiently, no ozone nearly is produced, no static electricity is accumulated, thus being safe and environment protective and having wide application range.

The invention discloses a method for determining the commutation failure of a high voltage direct current system, which comprises the following steps: S1 calculating the load component and the fault additional component of commutation voltage on a conversion bus of the high voltage direct current system when a fault occurs in a certain point thereof under a given fault close angle; S2 determining an integral interval and calculating the actual commutation voltage time area; S3 comparing the actual commutation voltage time area with the critical commutation voltage time area and determining whether the fault of the point can cause the commutation failure or not; S4 repeating the step S1 to step S3 and determining an alternating current fault region which causes the commutation failure of the high voltage direct current system. The invention further discloses a device for determining the commutation failure of the high voltage direct current system, which comprises a preparing unit, a calculation unit and a determining unit. The method and the device can greatly reduce the calculation scale, lead the precision to meet the needs of engineering applications, disclose the mechanism of how the fault close angle affects the commutation failure and be applicable to the analysis of fault steady state and fault transient state.

A hybrid green uninterruptible power system including an input port, a boost module, a secondary battery, a bi-directional converter module, and an inverter module is provided. The boost module converts an AC utility power into a high voltage DC power. The bi-directional converter module includes a multi-winding transformer for either converting the high-voltage DC power into a low-voltage DC power for charging the secondary battery, or for releasing and boosting the power stored in the secondary battery. The multi-winding transformer further induces an additional DC power when converting the power. Whereby, the hybrid green uninterruptible power system is able to generate the additional DC power all the time and optimizes its energy converting efficiency between the secondary battery and an external device consuming DC power.

The invention belongs to the technical field of electrostatic spinning and relates to a portable handheld electrostatic spinning device. The top of a pushing rod of a medical syringe is provided with a pressure welding switch, a metal foil is arranged on the top side fixedly, a spinning solution is arranged in a front end inner cavity of the medical syringe, a square battery and a high-voltage direct-current inverter are arranged fixedly on the side wall of the syringe in a butt joint mode, and a stainless steel needle head which is used for spinning is arranged at the bottom end of the syringe in an inserting mode. A conventional medical syringe needle head structure and the syringe are combined and matched, the spinning solution is stored in the inner cavity of the medical syringe which is provided with the stainless steel needle head, the square battery provides a power supply for the high-voltage direct-current inverter, when the direct current voltage is inverted, the voltage in the unit of kilovolt, the positive pole of the high-voltage direct-current inverter is communicated electrically with the stainless steel needle head, and the negative pole of the high-voltage direct-current inverter is communicated electrically with the metal foils. The device is simple in overall structure, is convenient to carry, use and operate, applicable to occasions such as outdoor teaching and wounded rescue and high in economical value.

The invention discloses a method for current differential protection of a direct current electric transmission line, which comprises the following steps: according to a distributed parameter model of the electric transmission line, using mode transformation in a time domain to transform sampling values of direct current and direct current voltage into a modulus; then using the mode voltage and the current of two ends from two ends of a line respectively to calculate mode current of certain point of the line at each moment; and using the mode current to directly construct a current differential protection criterion, or synthesizing electrode current through electrode mode inverse transformation, and then constructing the current differential protection criterion according to the electrode current. The method can improve the sensitivity and the reliability of direct current line protection, has good controllability and high security, has a complete setting theory, overcomes the defects of the conventional traveling-wave protection as the main protection of a high-voltage direct current line, and requires no recognition of a traveling-wave wave head; besides, the calculation is simple. The method is mainly used for the current differential protection of the direct current electric transmission line in an electric power system, in particular for the protection of an ultra / extra high-voltage direct current electric transmission line.

The invention provides a biological mass thermal decomposition, gasification and purification method which comprises, disintegrating the biological mass, gasifying in a furnace, obtaining retort gas, cyclone dedusting, cooling down and purifying, high voltage static coke trapping, making the coke tar bubbles and dust in the coal gas deposit onto the coke collection poles, thus purifying the coal gas, finally washing and dewatering.

The invention discloses a direct current de-icing device based on a full-bridge modular multilevel converter. The full-bridge modular multilevel converter has a three-phase bridge structure, each phase of the converter comprises an upper bridge arm and a lower bridge arm, the upper and lower bridge arms which are respectively formed by serially connecting N full-bridge power modules end to end, and the full-bridge power modules form a chain type multilevel structure, the front ends of the first power modules of the upper bridge arms of all phases are connected to form the positive pole of a public direct current bus; the tail ends of the Nth power modules of all lower bridge arms of all phases are connected to form the negative pole of the public direct current bus; the tail ends of the Nth power modules of all upper bridge arms are connected with the front ends of the first power modules of the respective lower bridge arms of the phases by smoothing reactors; and the center of the electric reactor serves as the alternating current bus of the phase. The device has high high-voltage direct current output capacity and the direct current voltage of the device can be regulated continuously from zero; on the other hand, the fully compatible chain type scalable vector graphics (SVG) topology can realize quick dynamic reactive regulation; and the device has the combined functions of direct current de-icing and alternating current dynamic reactive compensation.

The invention relates to a high-voltage direct-current direct-current (HVDC-DC) power electronic converter transformer comprising a cascade modular converter (1), a double-winding medium or high-frequency transformer (2) and a fully-controlled H bridge (3). The cascade modular converter (1) consists of two same bridge arms, and the two bridge arms are formed by connecting the same number of sub-modules end to end in a cascading way; the middle points of both the two bridge arms are respectively connected with two leads of the primary side of the double-winding medium or high-frequency transformer (2); and the secondary side of the double-winding medium or high-frequency transformer (2) is directly connected with the fully-controlled H bridge (3) or is connected in series with a resonant capacitor (5) between the double-winding medium or high-frequency transformer (2) and the fully-controlled H bridge (3). The HVDC-DC power electronic converter transformer can realize the conversion of the high-voltage DC voltage and the low-voltage DC voltage and has the electrical isolation function. Compared with the prior HVDC-DC converting device, the HVDC-DC power electronic converter transformer has the advantages of small volume and light weight.

The invention discloses an online detection method and protection device for direct current system arc faults. Characteristics of current alternating components of a power circuit in the power-on starting process, the normal work process and the overload fault process of the power circuit and characteristics of the current alternating components of the power circuit during arc generating are combined, selected arc current characteristic components include peak-to-peak values and standard deviations of a time domain and a frequency component power sum within the range from 1 kHz to 100 kHz after noise of specific frequency points of a load is filtered, mahalanobis distance values of the real-time characteristic components and the characteristic components in the power-on starting process, the normal work process and the overload fault process of the power circuit through a mahalanobis distance algorithm, and the mahalanobis distance values are compared with a threshold value set in the learning process to detect whether a single arc is generated or not. By means of the technical scheme, the online detection method and protection device have advantages of being high in university, high in detection rate and low in misjudgment rate, and can be widely applied to low-voltage and high-voltage electric power systems and photovoltaic cell systems of airplanes, electric vehicles and ships, and civil high-voltage direct current power distribution systems.