67 results about "Four-current" patented technology

A direct current feeder protection system includes six conductors, four current sensors sensing four currents flowing in four of the conductors, four circuit interrupters interrupting currents flowing in the four conductors, and a processor cooperating with the current sensors to input four sensed currents, and to output a number of commands to the circuit interrupters. The processor includes a routine detecting a number of: a directional current fault of the sensed currents, a differential current fault of the sensed first and third currents or the sensed second and fourth currents, and a residual current fault of the sensed first and second currents or the sensed third and fourth currents, and to responsively output the commands. The first, fifth and third conductors are electrically connected in series with two of the circuit interrupters, and the second, sixth and fourth conductors are electrically connected in series with the other circuit interrupters.

An apparatus and method for multi-point detection in a power source equipment (PSE) device is provided. During multi-point detection, a series of at least four currents is sequentially applied to a link port of the PSE device. Each current is applied during a different measurement interval. A voltage measurement sample is obtained for each of the measurement intervals. A difference in voltage between alternating voltage samples is determined and used by a detection module to determine whether a valid power device is coupled to the link port of the PSE.

The invention discloses a direct current method for bed-parallel advanced detection of water bearing structure in mine tunnel. Common advanced detection technology comprises a seismic reflection wave method, a Rayleigh wave method and the like, but with the extensive application of a fully-mechanized roadheader, the above methods are harder to adapt to the present production task requirements. The method of the invention is as follows: a mine direct current method seven-electrode series detecting device is used to arrange four current-emitting electrodes of A1, A2, A3 and A4 which are arranged on one straight line near a mine tunnel heading end, and the four current-emitting electrodes respectively form a loop with another current-emitting electrode B arranged at infinity to supply direct current under the ground, so that a direct current field is built; meanwhile, two electrodes M and N with relatively fixed distance behind the tunnel are used for measuring the distribution rule of the electric field; after treatment with special mating interpreting technology, electrical property distribution information in a geologic body 0-140m ahead a drifting tunnel or a tunnel is obtained. The invention has the advantages of small workload, high speed, small possibility of influence by personal factors, high objectivity and high accuracy, and belongs to a non-destructive detection method.

To accurately measure the muscle mass, body-fat ratio and / or other information of the subject, the human body is divided into nine segments including the trunk, right and left forearms, right and left upper arms, right and left thigh, and right and left crura. Four distal voltage-measuring points Pv are determined at the wrists and ankles, and four proximal voltage-measuring points Pv are determined at the elbows and knees. Four current-carrying electrodes and four measuring electrodes are used. First, the measuring electrodes are attached to distal points, and the impedances of four limbs and the trunk are measured. Then, the measuring electrodes are moved to proximal points, and the impedances of four limbs and the trunk are measured. From the measurement result, the measurement value is calculated for each segment. Then, using estimation formulae created by a regression analysis based on the data collected with an MRI, the body composition such as a muscle mass is estimated from the measurement values of the impedances and body specific information including the height, weight, etc.

An output stage for a Class-G amplifier includes four current mirrors, (CmpL) powered by a first low voltage supply (VspL), (Cmph) powered by a first high voltage supply (Vsph), (CmmL ) powered by a second low voltage supply (VsmL), and (Cmmh) powered by a second high voltage supply (Vsmh). The outputs of the current mirrors are connected together to form an output of the output stage. A buffer (10), whose input forms an input to the output stage, includes a first transistor (19) and a second transistor (27) connected in an emitter follower configuration, which are used to steer the buffer's output either through the first transistor (19) to a first switch (69) or through the second transistor (27) to a second switch (84). The first switch (69), which is controlled by a first comparator (68) connects a collector of the first transistor (19) to either the input to the first current mirror (CmpL) or the input to said second current mirror (Cmph). The second switch (84), which is controlled by a second comparator (82) connects a collector of the second transistor (27) to either the input to the third current mirror (CmmL) or the input to the fourth current mirror (Cmmh). This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims.

The invention discloses a positive and negative sequence component separation method of low-voltage ride-through control of a photovoltaic grid-connected inverter. The positive and negative sequence component separation method of the low-voltage ride-through control of the photovoltaic grid-connected inverter is characterized by comprising the following steps of obtaining three-phase voltage instantaneous values and three-phase current instantaneous values through detection of voltage and current of a power gird, obtaining output signals which are a voltage synchronous phase angle sine value and a voltage synchronous phase angle cosine value of the power grid, and output signals which are a current synchronous phase angle sine value and a current synchronous phase angle cosine value of the power grid through processing of a synchronous phase locking unit, obtaining three-phase reference voltages of the photovoltaic grid-connected inverter according to four obtained voltage positive and negative sequence components, four obtained current positive and negative sequence components and four current positive and negative sequence component set values which are set according to output power of a photovoltaic cell panel through a current control unit, and obtaining a PWM switching signal corresponding to the three-phase inverter according to the three-phase reference voltages and bipolar triangle carrier signals through a PWM wave generating unit to achieve the low-voltage ride-through control of the photovoltaic grid-connected inverter. The positive and negative sequence component separation method of the low-voltage ride-through control of the photovoltaic grid-connected inverter is simple and reliable in method and good in practicability.

The invention relates to a gain and slew rate enhancement type amplifier, which is realized by a current mirror type operational transconductance amplifier (OTA). The gain and slew rate enhancement type amplifier consists of a differential input stage unit and a double-end to single-end unit. The amplifier disclosed by the invention adopts a mode of adding current control variable resistors to optimize a current mirror structure, and a circuit can obtain higher voltage gain and bandwidth under the situation of the same static power consumption. During big-signal inputting, a higher slew rate can be obtained. According to the gain and slew rate enhancement type amplifier disclosed by the invention, by only adding four current control variable resistors, the circuit slew rate is improved to 4.8V / mu s from 0.88V / mu s and the band width is improved to 4.3MHz from 2.54MHz on the premise that the amplifier keeps the same power consumption. The circuit disclosed by the invention can be widely applied to the circuit fields such as a switched capacitor circuit, a data converter and a mixed signal system on chip.

A utility distribution pedestal for marine and recreational vehicles can be entirely separated and removed from its base without disturbing the service connections. Pedestals with different selections of receptacles can be quickly exchanged to change the service provided by any given pedestal location. Individual receptacle panels in the pedestal offering different combinations of receptacles can easily be added or exchanged after initial installation as utility needs change or for maintenance without any screw terminal wire removal. A metering system using four current transformers is controlled by an integrated mechanical jumper for switching the system into single or two phase configurations for one or two user readouts or a three-phase configuration for a one user readout. No pedestal disassembly or assembly is required to change these configurations. Remote monitoring for wireless metering and electromechanical counters may also be employed.

Methods and apparatus are provided for separating DC and AC components of a composite signal Is=Idc+Iac from a current source, e.g., a photodiode current source. Four current mirrors CM-1 . . . CM-4 are used with common branches and overlap. CM-1 through CM-3 mirror Is and CM-4 mirrors Idc where Iac has been removed by a frequency selective branch. Outputs of the Cm-3 and Cm-4 are combined at a node to provide a signal proportional substantially only to Iac. Complementary devices are used where Cm-1 and Cm-4 are of one type and Cm-2 and Cm-3 are of opposite type. The arrangement allows detection of AC signals (e.g., pulses) that are orders of magnitude smaller than the DC background. An I-to-V converter with a large feedback resistance is used at the output to produce a comparatively large voltage output proportional to Iac.

Methods and apparatus are provided for separating DC and AC components of a composite signal Is=Idc+Iac from a current source, e.g., a photodiode current source. Four current mirrors CM-1 . . . CM-4 are used with common branches and overlap. CM-1 through CM-3 mirror Is and CM-4 mirrors Idc where lac has been removed by a frequency selective branch. Outputs of the Cm-3 and Cm-4 are combined at a node to provide a signal proportional substantially only to Iac. Complementary devices are used where Cm-1 and Cm-4 are of one type and Cm-2 and Cm-3 are of opposite type. The arrangement allows detection of AC signals (e.g., pulses) that are orders of magnitude smaller than the DC background. An I-to-V converter with a large feedback resistance is used at the output to produce a comparatively large voltage output proportional to lac.

The invention belongs to the field of sensing technologies, and specifically relates to a novel temperature self-compensating strain gauge used in a temperature-variable environment, particularly in an environment with temperature gradient. The strain gauge comprises a substrate, four electrodes and four sensitive grids, wherein the four electrodes and the four sensitive grids are arranged in a mutually orthogonal manner, and the four sensitive grids are formed by four isotropic sensitive grid foils which are the same in size and uniform in thickness; the four sensitive grids are mutually connected to form a Wheatstone bridge, two adjacent sensitive grids in the bridge form a current channel, and the four sensitive grids are mutually connected to form four current channels; and the four current channels are respectively connected with the four electrodes. The strain gauge can compensate measurement errors caused by a resistance temperature effect of the material of the sensitive gridsand thermal expansion of a sensitive element and a test piece through the self structure, so that the temperature compensation effect of the strain gauge can be well guaranteed only by depending on the consistency of the processing technology and material, and an additional temperature compensation circuit is not needed.

A fully differential current feedback amplifier suitable for using in a fully differential operational amplifier circuit is disclosed. Symmetrical low input impedance input circuits receive a differential input current and provide a set of four currents that correspond to the differential input currents. These current are input to a pair of subtraction circuits that output a first voltage signal responsive to the positive difference and a second voltage signal responsive to the negative difference. In some embodiments these signals may be further amplified. A common mode circuit is provided that averages the output voltage and feeds back current in response to the subtraction circuits. In this way the average common mode output DC voltage can be set to particular voltage levels.

The embodiment of the invention discloses a digital phase shifter comprising a logic control circuit, at least four current digital-to-analog converters, at least four amplifiers and a vector summation circuit. The logic control circuit generates four N-bit digital phase shifting control signals according to (N+2)-bit digital control source signals to be respectively inputted to the four current digital-to-analog converters. The four current digital-to-analog converters are respectively connected in series with the four amplifiers so as to realize selection and amplification of four orthogonal input signals. The vector summation circuit synthesizes the amplification signals outputted by the four amplifiers so as to obtain the signals of which the phase can be shifted within the range of 360 degrees. The digital phase shifter is simple in circuit structure without additional arrangement of a phase shifting switching circuit so that noise can be reduced and the phase error / amplitude error can be improved; the circuit area is small and the chip cost can be reduced; and the phase shifting accuracy is high, and the accuracy value of the digital phase shifter can be adjusted by changing the total bits of the digital control source signals and the accuracy of the current digital-to-analog converters so as to meet different phase shifter design requirements.

The invention discloses a rail transit stray current detection method and a detection system, which relate to the technical field of rail transit and solve the technical defect that local measurement by the existing stray current detection method results in poor measurement result precision. Through four current sensors, current values in preset sections at two ends of two return current rails of an operating rail are detected respectively, the four current values synchronously communicate to a processing module respectively, the processing module compares the current value sum of two sensors at one end of the two return current rails and the current value sum of two sensors at the other end of the two return current rails, a difference is calculated, the difference is the rail transit stray current value, the processing module outputs the rail transit stray current value to a display module, and the rail transit stray current value is displayed. The difference is calculated according to the current values at two ends, the rail transit stray current value is thus obtained, the subway stray current is thus analyzed comprehensively on the whole, and the stray current detection accuracy is improved.

Two inverters (INV1, INV2) supply phase currents to three-phase coils (Y1, Y2). Although two phase currents must conventionally be measured and four current sensors are thus required, according to the present invention, the number of phase currents to be measured is reduced as a result of use of an observer for phase current estimation.

The invention discloses a method for detecting the initial position of a rotor of a power robot. The method comprises the steps of firstly exerting three different voltage pulses on a motor by controlling a driving circuit, respectively detecting the phase current response peak values of the phase A / the phase B / the phase C, comparing the phase current peak values of the three phases, initially judging the section where the rotor is located, controlling an inverter to exert a voltage pulse relative to the section again according to the section where the rotor is located, meanwhile, detecting the current peak value of the phase, comparing the current peak value of the phase and the detected current peak value in the first step, selecting the three detection values in the four current peak value detecting processes for triangle function transformation, and finally determining the angle of the initial position of the rotor. The method for detecting the initial position of the rotor of a permanent magnet synchronous motor can detect the initial position of the rotor of the permanent magnet synchronous motor quite accurately, and achieve smooth starting of the motor, the implementation process is simple, any motor parameters are not required to be depended on, the measuring result is accurate, and the method has the high engineering practical value.

A flat emitter comprises four current-supply heating legs. Half lighting for a small focus in which a current is supplied to heat only a region narrower and full lighting for a large focus in which a current is supplied to heat the entire region are selectable according to the combination of the legs. Either one of a set of the two full-lighting current-supply heating legs for the full lighting and a set of the two half-lighting current-supply heating legs for the half lighting is linearly formed, and the other is formed to be bent plural times in zigzag to set the space between the full-lighting current-supply heating leg and the half-lighting current-supply heating leg, which are adjacent to each other, at their terminals to be larger than the space at their base parts.

The invention relates to the technical field of electrotechnics and electronics, discloses a diagnostic method for the mechanical fault of a circuit breaker and a device for the mechanical fault of the circuit breaker, and aims at solving the technical problem that the diagnosis on the mechanical fault of the circuit breaker is not accurate enough in the prior art. The method comprises the following steps of detecting and obtaining the current waveform of a circuit where an electromagnet coil of the circuit breaker is located in the case of operating the circuit breaker; extracting first characteristic parameters of the circuit breaker from the current waveform, wherein the first characteristic parameters comprise five characteristic moments and four current amplitude parameters; based on a corresponding relationship between the characteristic parameters and mechanical states, determining a first mechanical state, which corresponds to the first characteristic parameters, of the circuit breaker, wherein the first mechanical state represents a mechanical fault state of the circuit breaker. By applying the method and the device, the technical effect that the diagnosis on the mechanical fault of the circuit breaker is more accurate and more convenient is realized.

A so-called inter-macroblock parallelism is proposed for motion estimation. First, pixel data of one of the consecutive candidate blocks in an overlapped region of search windows of current blocks in a reference frame including reference blocks corresponding to the current blocks are read and transferred to a plurality of processing element (PE) arrays in parallel. The plurality of PE arrays are used to determine the match situation of the current blocks and the reference blocks. Then, the above process is repeated for the rest of the candidate blocks in sequence. For example, if there are four current blocks CB1-CB4 and four consecutive candidate blocks, at the beginning the data of the first candidate block are read and transferred to four PE arrays in parallel, and so to the second, third and fourth candidate blocks in sequence, and the four PE arrays calculate SADs for CB1 to CB4, respectively.

The invention discloses a method for detecting the initial position of a rotor of a power robot. The method comprises the steps of firstly exerting three high-frequency low-voltage pulses on a motor by controlling a driving circuit, utilizing an average current oblique differential method for calculating wire inductance values Lab, Lbc and Lac, comparing the inductance values Lab, Lbc and Lac to determine the section of the position angle of the rotor, controlling an inverter to exert a high-frequency low-voltage pulse again according to the section of the position angle of the rotor, selecting the three optimal detection values in the four current peak value detecting processes for rotational coordinate transformation, and finally determining the initial position angle of the rotor. The method for detecting the initial position of the rotor of a permanent magnet synchronous motor can detect the initial position of the rotor of the permanent magnet synchronous motor quite accurately, and achieve smooth starting of the motor, the implementation process is simple, any motor parameters are not required to be depended on, the measuring result is accurate, and the method has the high engineering practical value.

The present invention discloses a current measurement method. The method comprises the step of cable current measurement through adoption of a current sensor. The current sensor comprises an installation seat, a current detection module, a DSP signal processor, an oscilloscope, a voltage follower and a resistive divider. The method also comprises the following steps: S1: four current detection units are employed to measure four measurement points (Bx, By), and then the resultant field B of each point is obtained according to the each point (Bx, By); S2, the ratios, kx, ky, of the resultant fields of two measurement points on the installation seat on the same vertical direction are calculated; S3, central point coordinates (x0, y0) of the portion, located in a punched hole, of a cable to be measured are calculated; S4, after the central point coordinates (x0, y0) of the portion, located in the punched hole, of the cable to be measured are calculated, distances between each measurement point and the (x0, y0) are calculated, and the current values of the four measurement points are calculated; and S5, the average value of the four current values is obtained, and the current value of the cable is obtained. The current value measured through the current measurement method is more accurate.

An apparatus for limiting a current of a line or breaking a current, and a control method thereof are disclosed. The apparatus includes a current breaking branch (29) and a bridge branch. The bridge branch includes two bridge arms formed by four identical current commutation branches. Every two of the four current commutation branches are connected in series, and the formed two bridge arms are then connected in parallel. The two bridge arms are both connected in parallel to the current breaking branch, and middle points of the two bridge arms are separately connected to two ends of a line. Each current commutation branch includes at least one high-speed isolation switch (6) and at least one bidirectional power semiconductor switch (10) that are connected in series. The apparatus can turn off currents in two directions.

The invention relates to a safe high efficient low power consumption switch power supply circuit, comprising a control circuit for controlling frequency of control switch power supply, comprising a first power switch unit located between an output end and a grounding end of a clamper; a starting control circuit for actuating the first power switch unit when starting; a second switch unit located between the first power switch unit and connecting point and grounding end of the starting control circuit. A gate of the second switch unit has four current sources as actuating current sources, a light load pulse width controller for regulating output pulse width and oscillation frequency; a third power switch unit connected between the output end of the first power switch unit and the output end of the optical coupler saves energy and reduces consumption, which saves output current-limiting circuit in traditional circuit, improves conversion efficiency of the circuit, voltage adaptability of the product and reliability of the product enabling greater safety of the product.

The invention relates to an electronic simulation device for a five-wire system alternating current point switch. The device is connected with a point switch control circuit and used for simulating positioning drive, positioning representing, anti-position drive and anti-position representing functions of the point switch, and can give corresponding state indicator lamps. The simulation device comprises an interface connecting line, a resistor for simulating impedance of a three-phase motor winding inside the point switch, a diode Z1 for forming a representing loop, two relays for simulating ashutter inside the point switch, four LED indicator lamps which are the positioning drive indicator lamp, the anti-position drive indicator lamp, the anti-position representing indicator lamp and thepositioning representing indicator lamp, and four current transformers connected in the main loop in series preliminarily for sensing loop current and secondarily generating a control circuit. Compared with the prior art, the device has the advantages of being small in size, low in weight, convenient to install and arrange.

The invention relates to a method and a system for driving the electromagnetic valve of a diesel engine, comprising the following steps: (1) setting the driving system comprising the electromagnetic valve, a sampling and driving unit and a processor, wherein a diesel engine managing module is preset; (2) presetting the injection-control signal duration, the maximum values of a first, a second, a third and current-control stages durations, the driving current target values of the first, second, third and a fourth current-control stages in the engine managing module; (3) calculating the durations of the four current-control stages by the engine managing module according to the preset injection-control signal duration; and (4) comparing the differences between the driving current target values and the actual values in the first, second, third and fourth stages by the engine managing module, and adjusting the driving current of the electromagnetic valve so as to enable the electromagneticvalve to be switched off and then partially switched on in the first current-control stage, to be partially switched on in the second current-control stage, to be partially switched on and then totally switched on in the third current-control stage and to be totally switched off in the fourth current-control stage. The invention is mainly applied in the electromagnetic valve driving system, in particular to an electronically controlled diesel engine.

The present invention belongs to the field of linear electronic circuit technology. The high-frequency multiple-pulse ultrasonic emission driver and receiver circuit includes receiving pre-amplifiers, four oppositely connected diode pairs, each of which is connected between one of four current drivers and one of four receiving pre-amplifiers, each of which consists of analogue switch, low-pass RC filter, coupling capacitors, and variable-gain high-frequency amplifier. The present invention can produce high-frequency differential current driving signal for the piezoelectric ceramic chip as the sensor of ultrasonic flowmeter in less delay and small drift and the receiver circuit has high anti-jamming performance.

The invention discloses a method and system for predicting the remaining power of an electronic lock. The system comprises a data acquisition module, an execution time calculation module, a current battery remaining power calculation module and a battery capacity comparison module which are sequentially connected. The method and system for predicting the remaining power of an electronic lock, obtain the current value of each power-consuming module and calculate the respective execution time of the power-consuming module so as to calculate the current remaining capacity of the battery, comparethe current remaining capacity with the normal capacity of the battery so as to clearly obtain the ratio of the remaining battery capacity, and give an alarm when the ratio is lower than a first preset alarm threshold. The method and system do not require a large amount of test data and can obtain the remaining battery power by using four current values and four execution times, and the method issimple and effective.

The invention discloses a low voltage residual leak current measurement instrument and working method thereof. The measurement instrument includes a micro-processor, a power module, a current samplingdevice, an amplification circuit, a display screen and a wireless communication module. The current sampling device includes four current transformers used for collecting L1 line current, L2 line curre,t L3 line current and N line current in a three-phase circuit respectively. The amplification circuit is connected electrically to the current transformers and the microprocessor separately. The microprocessor is electrically connected with the power module, the display screen and the wireless communication module separately. According to the invention, actual current amplitudes of different lines in the three-phase circuit and the phase relation among the actual current amplitudes can be detected; also, leak current amplitude and phase can be determined.

The invention discloses a vehicle vertical load and road surface gradient estimation system and an estimation method thereof. The system comprises current signal acquisition units, a current signal receiving unit, a wheel speed sensor, an acceleration sensor and a microprocessor, wherein four current signal acquisition units are respectively embedded in tire surfaces of four wheels of vehicles tires; the current signal acquisition unit and the current signal receiving unit are in wireless connection; and an output end of the current signal receiving unit, the output end of the wheel speed sensor and the output end of the acceleration sensor are connected with an input end of the microprocessor. Compared with the prior art, the vertical load and road surface gradient estimation system and the estimation method thereof have the advantages that the vehicle vertical load and the road surface gradient are effectively estimated based on a principle of Kalman filtering and a least square method by means of the positive piezoelectric effect of a power generation crystal.