34results about How to "Small current change" patented technology

The invention discloses a driving power supply of a ballast type LED (Light-Emitting Diode) lamp, comprising a capacitor (C) and a low-consumption inductive ballast (L). The driving power supply is characterized in that a rectifying element (D) is connected between the A end and an input N end of the low-consumption inductive ballast (L); and the LED lamp is connected between rectifying output ends (B and C). The driving power supply has the advantages of less self power consumption, low temperature rise, long service life, fewer elements, high working reliability and less harmonic content. The driving power supply is an ideal driving power supply of the LED lamp.

The invention provides a variable transconductance circuit. The variable transconductance device includes a voltage-current conversion circuit that outputs a current signal that is linear relative to the input voltage signal (Vi); the first MOS transistor and the second MOS transistor (M1, M2) input the above-mentioned current signal and convert it into The voltage signal subjected to square root compression; and the 3rd MOS transistor and the 4th MOS transistor (M3, M4), which convert the voltage signal subjected to square root compression into a linear current signal, by making the 1st MOS transistor and the 2nd MOS transistor (M1, M4) respectively The bias current (Ia) of M2) and the bias current (Ib) of the third MOS transistor and the fourth MOS transistor (M3, M4) are changed to control gm, which can be realized with a low power supply voltage of about 3V in one circuit The variable gm is about 20 times, and can solve the problem of power consumption and increase of the installation circuit area.

The invention discloses a multichannel value of resistance automation measuring system. The multichannel value of resistance automation measuring system comprises a burn-in power source, a multichannel electronic switch array, a data collector, a current-limiting resistance, a circuit protection unit and a computer, wherein the multichannel electronic switch array is a multichannel single-pole double-bladed switch array, according to a test requirement of arbitrary one-channel component in multichannel infrared devices, the channel component is disconnected with the burn-in power source and is connected with the data collector to finish automatic switch between a try state and a test state of the component; simultaneously, the data collector is used for measuring value of resistance of the switched component to achieve the aim that the value of the resistance is automatically measured. By the adoption of a method that the computer sends command to a RS232 interface means of the data collector, the measured data are transferred to the computer to be stored; by the adoption of the system, the facts that the value of the resistance of the multichannel component is automatically measured and the data of the multichannel component is automatically stored are achieved, the rate, the accuracy and the data size of collecting component burn-in data are improved.

The invention discloses a novel energy storage system experiment platform and a working method, and the experiment platform comprises an array simulation module, an energy storage element and a management module thereof, a charging and discharging control module, a main power module, an intelligent control module, a DC load module, a serial port management module, an LAN management module and an upper computer. The array simulation module is used for providing an energy source for the energy storage element. The energy storage element and the management module include a lead-acid battery packand its management module, a lithium battery pack and its management module, a supercapacitor module and its management module. The charging and discharging control module includes a lead-acid batterypack charging and discharging control module, a lithium battery pack charging and discharging control module, and a super capacitor module charging and discharging control module. The main power module is used for providing working power for the experiment platform. The intelligent control module is used for controlling the charging and discharging strategy of the energy storage element. The DC load module is used for stimulating electrical equipment. The upper computer receives and displays the operating data and the operating state of the energy storage element through the serial port management module and the LAN management module.

The invention discloses a half-bridge circuit with an ultra-wide range of constant current that can be adjusted from 0V. The half-bridge circuit includes a PFC control circuit, a PFC boost circuit, a half-bridge control circuit, a half-bridge main circuit and a transformer circuit, and an external power supply is input to the PFC. The boost circuit is boosted by the PFC boost circuit and output to the main circuit of the half-bridge, and then output to the transformer circuit after constant current processing by the main circuit of the half-bridge, and then output to supply power to the load after being transformed by the transformer circuit, the PFC control circuit controls the PFC The boost circuit works, and the half-bridge control circuit controls the work of the half-bridge main circuit. The circuit structure of the present invention is simple, without adding additional circuits, it can realize wide constant current range and small current change, and can make the output terminals be connected in any number from one LED lamp to multiple lamps.

The invention provides a low-dropout shunt voltage stabilizer. The low-dropout shunt voltage stabilizer comprises a first current mirror module, a second current mirror module and an output module. The first end of the first current mirror module is electrically connected with an input voltage; the first current mirror module has high output impedance; the first end of the second current mirror module is electrically connected with the second end of the first current mirror module; the second end of the second current mirror module is electrically connected with a reference voltage; the outputend of the output module is electrically connected with the third end of the first current mirror module; the output end and the first end of the output module are electrically connected with the second current mirror module; and the second end of the output module is electrically connected with the reference voltage. According to the low-dropout shunt voltage stabilizer, a current mirror circuitwith high output impedance is formed by combining a low-voltage switch assembly and a high-voltage switch assembly, so that the current change caused by the large-amplitude input voltage range can bereduced, and the internal energy consumption of the low-dropout shunt voltage stabilizer can be reduced.

The invention discloses a method for removing and preventing wax of a mechanical recovery well by a microorganism wax removal and prevention composite bactericide. In the method, the microorganism composite bactericide is injected into a well bottom, and the concentration of the composite bactericide in well bottom liquid is not lower than 100mg / L, and is up to 50,000 mg / L; and an agent adding cycle is 10 to 28 days to ensure that the wax content of crude oil is reduced until the standard is met. Through a wax removal and prevention experiment of eight wells on which wax can be precipitated easily, compared with a method for removing and preventing wax by using a chemical wax removal and prevention agent, the method has the advantages that: the using amount of the microorganism wax removal and prevention agent is recued by more than 40 percent, the cost is saved by 20 to 50 percent, the agent adding cycle is more than two times the conventional agent adding cycle, and the economic benefit is obvious; moreover, during experiment, current of the mechanical recovery well changes slightly, and the current is in a stable state basically, and the effect is better or equal to that of the chemical wax removal and prevention agent. Therefore, the method has the advantages of low environmental pollution, low cost, long action period, high economic benefit and wide application range, plays an important role in the wax removal and prevention of the field of oil exploitation, and has wide application prospect.

The present invention provides a drive circuit and method for a sending end, including: a calibration control unit that generates a calibration control signal that varies with the process, power supply voltage or temperature; a current calibration unit that generates a calibration current based on the calibration control signal; generates a bias based on the calibration current A bias voltage generation unit for the voltage; an output stage drive unit for amplifying the output signal based on the bias voltage; and an impedance matching unit for adjusting the output impedance based on the calibration control signal. Generate a calibration control signal; generate a calibration current based on the calibration control signal to obtain a bias voltage; amplify the signal to be output under the action of the bias voltage, and obtain a stable output signal through impedance matching. The present invention effectively reduces the current and resistance changes caused by process, power supply voltage and temperature changes, meets the requirements of the HDMI2.0 protocol for output voltage amplitude changes at the sending end, achieves better impedance matching effects, and effectively improves signal transmission quality .

The invention relates to a control method of a photovoltaic LCL type grid-connected inverter. The control method is characterized by comprising the steps of: considering that a photovoltaic LCL type grid-connected inverter system has input uncertainty faults and actuator faults, establishing a fault mathematical model, and setting a fixed control distributive law; establishing a system state high-order sliding-mode observer and state estimation errors thereof according to the fault mathematical model, and adopting the high-order sliding-mode observer for realizing accurate estimation of system fault information; and constructing a continuous integral sliding-mode fault-tolerant controller mathematical model according to the fault mathematical model, the fixed control distributive law, the high-order sliding-mode observer and the state estimation errors thereof, wherein the continuous integral sliding-mode fault-tolerant controller mathematical model is used for processing the actuator faults directly. The control method is reasonable in design, can realize stable control under parameter uncertainty faults and actuator faults, and exhibits good tracking performance and fault tolerance. The control method provides a new idea for the design of a large-scale photovoltaic LCL type grid-connected inverter control system, and has a good engineering application prospect.

The invention discloses a direct-current micro-grid fault current controller and a control method thereof. The controller comprises a first switch tube, a second switch tube, an energy storage element and a capacitor; a collector of the first switch tube is connected to a positive electrode of the energy storage element, an emitter of the first switch tube is connected to a collector of the second switch tube, and an emitter of the second switch tube is connected to a negative electrode of the energy storage element; and the first end of the capacitor is connected between the first switch tube and the second switch tube, and the second end is connected to the emitter of the second switch tube. During normal operation, the interelectrode voltage is rated voltage, the current change is small, the control duty ratio is the first duty ratio, and constant voltage control is performed at the moment. When the interelectrode voltage is smaller than a preset threshold value, it is judged that a fault occurs, the duty ratio is switched into a second duty ratio, and constant current control is changed. After the fault is cleared, the interelectrode voltage rises, the duty ratio is switched into the first duty ratio, and the constant voltage control mode is recovered. The technical problems of poor current limiting effect and poor controllability in the prior art are solved.

The invention relates to a constant current source generation circuit, in particular to a constant current source generation circuit which is suitable for controlling current magnitude with direct current voltage, belonging to the technical field of an electronic circuit. The constant current source generation circuit comprises a sample amplifier U1, a summator U2, a triode N1, resistors R1, R2, R3, R4 and R5, a load and a power supply that are in circuit connection, wherein the sample amplifier U1 has sampling action for the power supply and is used for sampling the potential of the load, the summator U2 is an addition operation amplifier, the positive potential of the summator U2 is an intermediate value of the sample potential and the precise normal potential, and through two times of feedback amplification, the positive potential of the summator U2 is the sum of the sample potential and the precise normal potential; the output of the summator U2 is connected with a common base of the triode N1 to control the voltage output of the common base, the change the summator U2 is changed along with the change of the load sample, and then the voltage output is regulated by the triode N1 to reach potential balance. The constant current source generation circuit has the characteristics that the precision and the load power are improved, the circuit structure is simple, the cost is low, the control is easy, etc.

Provided is an overhead line fault positioning monitoring device, belonging to the field of power grid fault detection apparatus. The device includes a base and a fault detection module arranged on the base, the base is provided with an inclined plane, a semi-cylindrical flip cover is arranged corresponding to the inclined plane, the base is connected with the flip cover through a locking slide lock, the fault detection module includes two through type current transformers, one is an electricity obtaining ring and the other is a measuring ring, the winding of the electricity obtaining ring is connected to the input port of the power supply of the fault detection module, the winding of the measuring ring is connected to the monitoring signal input port of the fault detection module, each current transformer is divided into an upper half ring and a lower half ring that are fixed on the base, and the upper half ring is correspondingly arranged on the flip cover. The connection of the base and the flip cover is realized by the locking slide block structure, so that the installation is convenient; the double current transformers effectively solve the contradiction between the induction electricity obtaining and measurement, so that the measurement precision is improved while the normal work of the device is guaranteed, and the device has the characteristic of high fault capturing accuracy.

The invention provides a low-dropout shunt voltage stabilizer. The low-dropout shunt voltage stabilizer comprises a first current mirror module, a second current mirror module and an output module. The first end of the first current mirror module is electrically connected with an input voltage; the first current mirror module has high output impedance; the first end of the second current mirror module is electrically connected with the second end of the first current mirror module; the second end of the second current mirror module is electrically connected with a reference voltage; the outputend of the output module is electrically connected with the third end of the first current mirror module; the output end and the first end of the output module are electrically connected with the second current mirror module; and the second end of the output module is electrically connected with the reference voltage. According to the low-dropout shunt voltage stabilizer, a current mirror circuitwith high output impedance is formed by combining a low-voltage switch assembly and a high-voltage switch assembly, so that the current change caused by the large-amplitude input voltage range can bereduced, and the internal energy consumption of the low-dropout shunt voltage stabilizer can be reduced.

A variable transconductance circuit is provided in the invention. The variable transconductance circuit includes: a voltage-current conversion circuit for outputting a current signal linear with an input voltage signal (Vi); first and second MOS transistors (M1, M2) for converting the current signal received to a square-root compressed voltage signal; and third and fourth MOS transistors (M3, M4) for converting the square-root compressed voltage signal to a linear current signal. A bias current (Ia) at the first and the second MOS transistors (M1, M2) and a bias current (Ib) at the third and the fourth MOS transistors (M3, M4) are varied to control gm, thereby achieving about 20-times variation with a low power supply voltage of about 3V within one circuit to solve a problem that increase in power consumption and mounting circuit area.

This invention relates to a power adaptive wire coil of induction cookers including a bracket, magnetic strips distributed in radiation and a coil fixed on the bracket characterizing that part or whole of the coil passes through at least one ring magnetizer and the near-core end of at least one magnetic strip includes an upward corner higher than the top surface of the ring magnetizer to avoid burning down the upper part of the magnetizer with extra numbers of magnetic lines passing through at sudden unload.

A metal detector for a belt conveyer applied to the fields of coal, metallurgy, electricity, mine and the like comprises sensors, an oscillator, a high amplification circuit, a detection circuit, a low amplification circuit and an actuator. Two sensors L1 and L2 are arranged. The sensor L1 is sleeved on a belt, and the sensor L2 is placed below a conveying belt. A signal of the sensor L1 passes through an amplification channel and then enters a positive and negative phase detection circuit consisting of diodes D21 and D22. The detected signal is divided into two paths and then respectively enters amplifiers IC8 and IC9. The amplifier IC8 outputs the signal to an amplifier IC10 to drive the actuator. The amplifier IC9 outputs the signal to control the grid of a field effect tube V9. The field effect tube V9 and a resistor R30 which divide the voltage output the voltage to control the input voltage of the amplifier IC10. A signal of the sensor L2 passes through an amplification channel and then is outputted through an amplifier IC11 to drive a field effect tube V10. The field effect tube V10 and the resistor R30, which divide the voltage, control the input voltage of the amplifier IC10. The metal detector avoids the interference caused by reinforcing a wire connector in the conveying belt and the interference due to variation of magnetic inductivity in the process of conveying ore materials.