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

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 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.

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.