37results about How to "Reduce the rated voltage" patented technology

A solid electrolytic capacitor having a capacitor element which includes an anode foil and a cathode foil rolled with a separator interposed therebetween, and a solid electrolyte layer or an electrically conductive polymer layer provided therein. The anode foil is coated with a dielectric oxide film. The dielectric oxide film is an oxide film formed by oxidizing a film of a mono-metal nitride or a composite metal nitride formed on the anode foil. The mono-metal nitride is titanium nitride, zirconium nitride, tantalum nitride or niobium nitride. The composite metal nitride is aluminum titanium nitride, chromium titanium nitride, zirconium titanium nitride or titanium carbonitride.

A multi-port DC-DC autotransformer, which is used for realizing interconnected transmission among a plurality of DC systems of different voltage levels. The autotransformer comprises 2N-1 current converters. The 2N-1 current converters are connected in series in sequence at a DC side and are connected to an AC line at an AC side, and the positive electrode of the ith current converter and the negative electrode of the (2N-i)th current converter of the 2N-1 current converters connected in series in sequence are respectively and correspondingly connected to the positive electrode and the negative electrode of the ith DC system, where N is the number of DC systems, and i is the serial number of the current converter. Further disclosed are a capacity design method for the current converters in the autotransformer and a control method for the autotransformer. The autotransformer enables most of the power transmitted among various DC systems to be directly transmitted through the electrical interconnection among the various DC systems without DC-AC-DC conversion, so that the rated voltage and the operating loss of the various current converters are greatly reduced, thereby reducing operating costs.

The invention relates to a bidirectional DC-DC converter with intermediate conversion into AC power, including: a DC-AC conversion circuit using a plurality of MOSFETs; an AC-DC conversion circuit using a plurality of power diodes; a transformer; a pair of switches, one of which being inserted in series between a DC terminal of the DC-AC conversion circuit and the AC-DC conversion circuit and the other of which being inserted in series between another DC terminal of the DC-AC conversion circuit and the AC-DC conversion circuit; and a controller being adapted for turning on the pair of switches such that the plurality of power diodes of the AC-DC conversion circuit are reverse-biased where the AC power is transferred in the forward direction and turning off the pair of switches where the AC power is transferred in the backward direction.

The invention relates to a high-voltage power transmission and transformation current detecting technology which discloses an on-site accuracy detecting and testing line of a high-voltage current mutual inductor and is adapted to the on-site accuracy detection of an ultra-high voltage (750 kV) current mutual inductor. The on-site accuracy detecting and testing line of the high-voltage current mutual inductor comprises a voltage regulator, a current raising device, a compensated capacitor, a main loop, a testing power supply which is electrically connected with the first side of the voltage regulator, a standard current mutual inductor, an on-site current mutual inductor and a mutual inductor check meter, wherein the standard current mutual inductor and the on-site current mutual inductor are arranged on the main loop, the mutual inductor check meter is electrically connected with the standard current mutual inductor and the on-site current mutual inductor, the second side of the voltage regulator is electrically connected with the first side of the current raising device, and the second side of the current raising device is electrically connected with the main loop. The invention is characterized in that the compensated capacitor is connected in the main loop in series.

A differential driving circuit (200) for powering a light source (210) is disclosed. The differential driving circuit includes a first set of switches and a second set of switches. A first current from a power source (201) flows through the first set of switches (221,223) to charge a first energy storage element (225) when the first set of switches is turned on. A second current from the first energy storage element (225) flows through the second set of switches (222,224) to power the light source when the second set of switches are turned on. The differential driving circuit further includes a second energy storage element (250,260) coupled to the light source in parallel and for providing a differential voltage to the light source.

The invention discloses a dual-active full-bridge converter-based hybrid energy storage system and a control method therefor. The hybrid energy storage system comprises a supercapacitor, a lithium battery, a dual-active full-bridge converter, a Buck / Boost bidirectional converter and a direct current bus; and two kinds of energy storage equipment form a cascading type hybrid energy storage system. The supercapacitor is connected with the direct current bus through the dual-active full-bridge converter; by adoption of phase-shifting closed-loop control and by collecting the voltage information of the direct current bus, the output power of the hybrid energy storage system can be automatically regulated so as to stabilize the voltage of the direct current bus; the lithium battery is connected with the supercapacitor through the Buck / Boost bidirectional converter; and by adoption of voltage and current dual-closed-loop control, and by collecting the voltage of the supercapacitor, automatic charging and discharging of the lithium battery can be controlled, so that the voltage of the supercapacitor can be maintained within a working voltage range, so as to perform indirect compensation to power fluctuation of a direct current microgrid, reduce action frequency of the lithium battery, and effectively prolong the service life.

The invention discloses a transformerless hybrid active power amplifier and implementation and control methods thereof. The transformerless hybrid active power amplifier comprises a double-turned passive filter and a diode-clamped active filter. The diode-clamped active filter is a tri-level inverter. The double-turned passive filter comprises three passive filter branches connected with phases A, B and C of a power grid respectively. Each passive filter branch comprises an impregnated capacitor (C1), a divider capacitor (C2), a parallel capacitor (C3), a first inductor (L1) and a second inductor (L2). Impregnation points of the three passive filter branches are connected with three terminals on the alternating-current side of the tri-level inverter through three output inductors (L) respectively. The transformerless hybrid active power amplifier features both low cost of a PPF (passive power filter) and excellent filtering and dynamic performance of an APF (active power filter), is easy to implement and is effective in filtering.

A voltage source converter including a string of series connected active semiconducting elements. The converter includes in case of an active semiconducting element failure a calculation element configured to calculate an operation dc voltage including a sum of dc ratings of each remaining active semiconducting element in the string, and a regulator configured to regulate the converter to assume the operation dc voltage over the converter.

A lightning arrester degradation protection device, which relates to the technical field of lightning arresters. The upper end of the lightning arrester degradation protection device is connected to the lightning arrester, and the lower end is connected to the grounding copper bar. It includes a compensation impedance element, an increasing resistance switch and a control unit. The compensation impedance element One end is connected to the low-voltage end of the arrester, the compensation impedance element is connected in parallel with the resistance increasing switch and then grounded, the circuit after the compensation impedance element and the resistance increasing switch is connected in parallel is connected in series with the control unit through the magnetic flux sensor, and the described The control unit controls the connection of the increasing resistance switch. During normal operation, the increasing resistance switch is closed and the compensation impedance element is short-circuited, which is equivalent to directly grounding the ground terminal of the arrester. When the control unit detects that the leakage current of the arrester exceeds the limit value, it sends an opening command to drive the The resistance switch is disconnected, and the compensation impedance element is connected in series to the arrester circuit to achieve the purpose of reducing the leakage current.

The electrical switching device has an interrupter unit for interrupting and connecting an electrical line. The interrupter unit is connected with other closed interrupter unit. The electrical flashovers produced appear as electric arcs by connecting or interrupting the electrical conductor in the later interrupter unit. The later interrupter unit is switched, when connecting the electrical line before the former interrupter unit. The later interrupter unit is switched, when connecting the electrical line before the former interrupter unit and when interrupting the electrical line, after the former interrupter unit. An INDEPENDENT CLAIM is also included for method for switching an air-insulated grounding switch of electrical line.

Disclosed is a capacitor voltage balance control method of an MMC flying capacitor submodule. The method comprises the steps of: obtaining a voltage reference value of any bridge arm of an MMC; dividing the voltage reference value by a reference voltage of a second capacitor to obtain electrical level value and electric level complementary value needed by the bridge arm at the next moment; measuring voltages of an first capacitor and an second capacitor of each bridge arm submodule to generate a voltage original input sequence; respectively multiplying the odd-numbered bits in the voltage original input sequence by h1, and respectively multiplying the even-numbered bits in the voltage original input sequence by 2h1, so as to obtain a new normalized voltage sequence; successively comparingeach normalized capacitor voltage value in the normalized voltage sequence with other normalized capacitor voltage values in the sequence, summing the comparison results, and arranging the results inorder to obtain a sequence of numbers; measuring the current direction of the bridge arms to obtain a capacitor on-off state sequence; and generating a corresponding IGBT trigger pulse according to the capacitor on-off state sequence. The method improves the stability of the system based on flying capacitor submodules.

The invention provides a power decoupling circuit for a photovoltaic grid-connected inverter, and relates to circuit devices of alternating-current main lines or alternating-current power distribution networks. The power decoupling circuit is composed of a filter capacitor, an inductor, a decoupling capacitor A, a decoupling capacitor B, a switch tube A and a switch tube B. The decoupling capacitor A is in parallel connection with the filter capacitor after being in series connection with the decoupling capacitor B, a collector of the switch tube A in series connection with the switch tube B is connected to a positive pole node of the part, in parallel connection with the filter capacitor, of the decoupling capacitor A in series connection with the decoupling capacitor B,, an emitter of the switch tube B in series connection with the switch tube A is connected to a negative pole node of the part, in parallel connection with the filter capacitor, of the decoupling capacitor A in series connection with the decoupling capacitor B, and an intermediate node enabling the decoupling capacitor A to be in series connection with the decoupling capacitor B is connected to the connecting point of an emitter of the switch tube A and a collector of the switch tube B through the inductor. The defects that an existing photovoltaic grid-connected inverter needs large-capacity and large-size decoupling capacitors and is complex in structure and high in cost are overcome.

Disclosed is a three-phase 18-pulse asymmetric Y-shaped output winding phase-shifting rectifier. The three-phase 18-pulse asymmetric Y-shaped output winding phase-shifting rectifier includes a rectifier bridge and a three-phase 18-pulse asymmetric Y-shaped output winding phase-shifting rectifier transformer. The rectifier transformer is provided with a primary winding, a secondary winding and an iron core. Primary winding wiring is triangular, star-shaped, hexagonal or extended hexagonal. In the secondary winding, the phases each have a set of long side output winding which has the same numberof turns of each phase and are symmetrical and three-phase connected or not-connected and two sets of short side windings which have the same number of turns of each phase and are symmetrical, and the head end of each phase of the long side output winding is connected to the head ends of the other two phases of short side output windings or the tail end of each phase of the long side output winding is connected to the tail ends of the other two phases of the output windings to form three inequilateral Y-shaped windings. The primary winding and the secondary winding are arranged concentricallyor up-down on each phase of an iron core column and are wound after being insulated by metal foil or a conductor. The iron core is a three-phase iron core shaped like a Chinese character 'ri' or delta-shaped or three single-phase iron cores which are square-shaped, a shell type shaped like a Chinese character 'ri' or double-ring shaped shell type. The three-phase 18-pulse asymmetric Y-shaped output winding phase-shifting rectifier can be powered by a four-wire direct current system and is low in harmonic content and cost.