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163results about How to "Small inductance" patented technology

Active damping control method of lcl filter controllable rectification with current feedback on converter side

The invention relates to a LCL (Lower Control Unit) filtering controlled rectifying active damping control method of electric currents on a feedback variable current side, belonging to an active rectifying method of power electronics. The method comprises the following steps: a direct current voltage control unit is used for finishing the control on a direct current voltage and producing d-shaft active currents of an electric current control unit; a q-shaft current given is used for controlling reactive components of a rectifier; a soft phase locking unit is used for locking a power grid voltage phase position and realizing the synchronous rotational transformation of the power-grid voltage and sampling currents on the variable current side; the current given and a sampling actual value are fed into the electric current control unit; the output quantity of the electric current control unit is accumulated with the electric current on the variable current side which is fed back by usinga first-order high-pass filter to generate the given quantity of a voltage space vector unit; and finally, the voltage space vector unit generates six PWM (Pulse-Width Modulation) signals to finish the control on the rectifier. The method solves the stability problem of a LCL (Low Control Unit) filtering voltage type controlled rectifier and realizes the control of the rectifier on direct-currentvoltages and currents on line side under the condition that the electric current or voltage detection of a capacitor branch is not needed.
Owner:CHINA UNIV OF MINING & TECH +1

Input-series-output-parallel (ISOP) system having natural voltage sharing characteristic and control method thereof

The invention provides an input-series-output-parallel (ISOP) system having natural voltage sharing characteristic and a control method thereof. The system comprises n sub-modules, wherein each sub-module comprises a Boost converter and an LLC resonant converter, n is a natural number larger than or equal to 2, in each sub-module, the Boost converter is a front stage, the LLC resonant converter isa rear stage, an output of the Boost converter is used as an input of the LLC resonant converter, the two converters are connected by an intermediate bus capacitor, input ends of the Boost convertersof the n sub-modules are sequentially connected in series, a positive electrode of an input voltage source is connected with an input positive end of a first Boost converter, a negative electrode ofthe input voltage source is connected with an input negative end of an n(th) Boost converter, and output ends of the LLC resonant converters of the n sub-modules are connected in parallel and are respectively connected with a positive end and a negative end of an output resistor. By the system, no extra measure is needed to be added, input voltage sharing and output current sharing of the ISOP system can be achieved, and the influence of inconsistent parameter among the modules on a voltage sharing and current sharing effect is relatively small. The implement method is simple, and the reliability of the system can be greatly improved.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Three-fracture double-acting type high-speed permanent magnet repulsion switch and method thereof

The invention discloses a three-fracture double-acting type high-speed permanent magnet repulsion switch and a method of the three-fracture double-acting type high-speed permanent magnet repulsion switch and belongs to the field of direct-current switches. The three-fracture double-acting type high-speed permanent magnet repulsion switch comprises a switch body, high-speed electromagnetic repulsion mechanisms, permanent magnetic operating mechanisms, contact springs, insulation pull rods, opening driving circuits, closing driving circuits, a detecting unit and a control unit. Each moving contact is connected to one end of one insulation pull rod through one contact spring, the other end of each insulation pull rod is connected with a driving rod, and each driving rod penetrates through a metal disc in one high-speed electromagnetic repulsion mechanism and is connected with a moving iron core; the control unit is respectively connected with a detecting circuit, the opening driving circuits and the closing driving circuits; each opening driving circuit is connected with an opening coil and each closing driving circuit is connected with a closing coil. According to the three-fracture double-acting type high-speed permanent magnet repulsion switch, a fracture with a large opening distance is formed at a short time and the opening speed of the switch is increased; meanwhile, according to the switch, the two moving contacts and two fixed contacts are in contact in sequence, so that when opening operation is conducted, the problems of movement dispersibility generated when multiple switches are independently driven and the like are solved.
Owner:SHENYANG POLYTECHNIC UNIV

Voltage online monitoring device for power system

The invention discloses a voltage online monitoring device for a power system. A high-voltage capacitive voltage divider is connected with a bus-bar and operated in the grid to divide the voltage of the bus-bar for the first time, a low voltage arm signal is transmitted to a secondary resistance-capacitance divider through a first coaxial cable, the secondary resistance-capacitance divider carries out secondary voltage division on the low voltage arm signal, the voltage signal at the low voltage side is transmitted to a high-speed data acquisition card to be subjected to A / D conversion through a second coaxial cable, and then the obtained digital signal is transmitted to an industrial personal computer to be judged, stored and analyzed; the high-voltage capacitive voltage divider, the secondary resistance-capacitance divider, the high-speed data acquisition card and the industrial personal computer are respectively grounded. The voltage online monitoring device for the power system can reach the sampling rate per channel of 7.5 MS / s, can run in the grid for long time, is low in power consumption and convenient to maintain, can track and record various over-voltage and voltage dip waveforms in an online manner, has various analysis and waveform processing functions, and provides scientific basis for the safe and reliable running of the power system.
Owner:ELECTRIC POWER RES INST OF GUANGXI POWER GRID CO LTD

Cascading inductor based on metal magnetic slurry and preparation method thereof

The invention firstly aims to provide a cascading inductor based on metal magnetic slurry. The cascading inductor comprises a first base body, an interlayer and a second base body, wherein the first base body, the interlayer and the second base body are arranged from bottom to top. The interlayer comprises at least two single-layers arranged from bottom to top. Each single-layer comprises a dielectric layer, a packing layer and a coil electrode, wherein the dielectric layer is provided with a through hole in the vertical direction; the packing layer is arranged at the through hole, and the upper surface of the packing layer is not lower than the upper surface of the dielectric layer; the coil electrode is arranged on the upper surface of the dielectric layer and located around the packing layer; the packing layer comprises inorganic powder bodies composed of metal magnetic powder, lead-free glass powder, organic carriers and auxiliaries. The cascading inductor based on the metal magnetic slurry is simple in overall structure; since the packing layers are made of metal alloy materials with high saturation flux density, the saturation magnetization intensity of the whole cascading inductor is improved, and then the rated current is increased. The invention secondly aims to provide a preparation method of the cascading inductor based on the metal magnetic slurry. By means of the preparation method, the process steps are simple, the cost is low, and the cascading inductor is quite suitable for large-scale batch production.
Owner:SHENZHEN GUDIAN ELECTRONICS

Detecting structure and method for detecting turn-to-turn insulation fault of electric reactor through oscillation method

The invention relates to a detecting structure and method for detecting a turn-to-turn insulation fault of an electric reactor through an oscillation method. The structure comprises a discharging ball gap and a pulse capacitor respectively connected to one end of the electric reactor, wherein the other end of the discharging ball gap is connected to the negative electrode of a power supply, the positive electrode of the power supply is connected to the other end of the reactor, and the other end of the pulse capacitor is connected to the negative electrode of the power supply. Since a discharging ball gap and a pulse capacitor are respectively connected to one end of the electric reactor, the power supply provides electric energy, and the pulse capacitor is charged through the power supply. When the pulse capacitor is charged to a certain value, the discharging ball gap discharges, and the pulse capacitor and the reactor form a damped oscillation circuit of a certain frequency. When turn-to-turn short circuit fault occurs to the reactor, the inductance value is reduced, and the active loss is increased sharply. The wave-shaped oscillation period of the reactor is reduced, and the attenuation speed of amplitude is accelerated, so that presence or occurrence of turn-to-turn short circuit fault of the reactor can be detected accurately. The detecting structure and method are highly practical.
Owner:ZHUHAI LANRUIMENG ELECTRIC

Voltage-reduction structure LED driving circuit, and constant current driver and design method thereof

The invention provides a voltage-reduction structure LED driving circuit, and a constant current driver and a design method of the voltage-reduction structure LED driving circuit. The driver comprises a power switch, a zero cross detection circuit, an on-signal generation circuit and a driving circuit, wherein the power switch is directly or indirectly connected with an inductor in the voltage-reduction structure LED driving circuit, the zero cross detection circuit responds to inductor current and outputs a zero cross detection signal in a zero cross mode, the on-signal generation circuit obtains inductor current duration time according to a driving signal and the zero cross detection signal, determines the inductor current interruption time according to the inductor current duration time and generates a setting signal used for switching on of the power switch so that the ratio from the inductor current duration time to the inductor current interruption time can be kept as a preset value, and the driving circuit is used for generating the driving signal according to a resetting signal for switching off the power switch and the setting signal. Under the condition of the same output current, the peak current of the inductor is increased, the inductance amount of the inductor is reduced, and the driver is particularly suitable for occasions with low output current and low requirement for the inductance amount.
Owner:HANGZHOU SILAN MICROELECTRONICS

SEPIC feed buck-boost converter

The invention discloses an SEPIC feed buck-boost converter comprising an SEPIC circuit, a polarity inversion converting circuit and a controller which are mutually coupled. The SEPIC circuit is connected with a power source. The SEPIC circuit and the polarity inversion converting circuit are connected through a control switch. The polarity inversion converting circuit is connected with a load. When the control switch SISBB is closed, the SPPIC circuit stores the electric energy of the power source in an energy storing coupled inductor of the SEPIC circuit and the polarity inversion converting circuit; meanwhile, an energy storage coupled capacitor feeds back electric energy to the load through the polarity inversion converting circuit. When the control switch is switched off, the power source feeds back electric energy to the load through the SEPIC circuit, and electric energy is fed back to the load by the energy storing coupled inductor of the SEPIC circuit and the polarity inversion converting circuit through the SEPIC circuit and the polarity inversion converting circuit. By the adoption of the SEPIC feed buck-boost converter, the work efficiency of the converter is improved, output follow current of the converter can be achieved, and the output EMI of the converter is reduced.
Owner:STATE GRID CORP OF CHINA +1

High-precision downhole electromagnetic thickness-measuring caliper

The invention relates to a high-precision downhole electromagnetic thickness-measuring caliper. The high-precision downhole electromagnetic thickness-measuring caliper comprises a magnetic protective sleeve, a coil component, a control unit, a thickness measuring unit, a fixing component and a thickness measuring drive unit, wherein the coil component and the control unit are positioned in the magnetic protective sleeve; the thickness measuring unit is arranged on the fixing component; the fixing component is connected with the magnetic protective sleeve and the thickness measuring drive unit; the thickness measuring unit comprises a plurality of thickness measuring sensors; the coil component comprises a high-frequency electromagnetic coil and an intermediate-frequency electromagnetic coil; the high-frequency electromagnetic coil is positioned above the intermediate-frequency electromagnetic coil; the intermediate-frequency electromagnetic coil is positioned above the control unit; and the control unit is connected with the thickness measuring unit through the fixing component. The high-precision downhole electromagnetic thickness-measuring caliper solves the technical problems that the conventional electromagnetic thickness-measuring caliper can only perform point-to-point transmission and reception, and can only be used for qualitative analysis, and the measured thickness is a relative value. The high-precision downhole electromagnetic thickness-measuring caliper has high resolution and extremely high precision and can calculate absolute wall thickness of different sectors in the process of measuring borehole diameters.
Owner:XIAN SITAN INSTR
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