17results about How to "Avoid temperature drift" patented technology

The invention discloses a laser radar transmitting circuit with pulse width compensation and a control method thereof. The circuit comprises an optical pulse transmitting circuit and a pulse width sampling control signal feedback circuit. The method comprises the following steps: generating a starting pulse signal and exciting an optical pulse transmitting circuit to output a laser pulse signal according to the starting pulse signal; comparing the laser pulse signal with a reference voltage, and outputting a square wave pulse signal; capturing the square wave pulse signal to obtain time interval data; carrying out calculation according to the time interval data to obtain the pulse width of the laser pulse current and carrying out output voltage regulation processing to obtain a signal feedback quantity; and performing feedback regulation on the output voltage of the optical pulse transmitting circuit according to the signal feedback quantity. According to the embodiment of the invention, pulse width acquisition and adjustment of the optical pulse current can be realized, so that the pulse width stability of the optical pulse current is improved. The laser radar transmitting circuit can be widely applied to the technical field of laser radar transmitting circuits.

The invention relates to the technical field of sensors, and discloses a manufacturing process of an active constant-temperature absolute pressure sensor and a pressure sensor, and the manufacturing process comprises the following steps: carrying out the spin coating of photoresist on a POI silicon substrate; determining doping concentration and depth parameters; injecting monocrystalline silicon ions to form n-type and p-type thermocouples; removing the dielectric layer in the connection region by using an etching process, and exposing the thermocouple pair; forming a thermocouple interconnection line; depositing a metal layer on the surface of the piezoelectric layer, and depositing a dielectric layer to protect the piezoelectric electrode to obtain an upper substrate; manufacturing a dielectric layer, and manufacturing a cavity region to obtain a lower substrate; bonding the upper substrate and the lower substrate, and manufacturing a through hole to expose the thermocouple region; and forming a through hole seed layer, exposing an electrode interconnection pad region, and removing the photoresist. According to the invention, the magnitude / direction of the voltage at the two ends of the thermocouple pair can be controlled through the control circuit, the resonator is heated / cooled, the temperature of the resonator is kept constant, the temperature drift of the resonator is avoided, and the accuracy of air pressure detection is improved.

This invention discloses an automatic safety inspection device for central air conditioning outdoor units, belonging to the field of air conditioning outdoor unit detection technology. It includes: a handheld support assembly comprising a support plate and a handheld lever fixed to the side wall of the support plate, with a display host fixedly mounted on the handheld lever; and an external insulation assembly comprising an insulation side plate fixedly mounted on the support plate, with an external insulation cover fixedly connected to the side of the insulation side plate away from the handheld lever, the side of the external insulation cover away from the insulation side plate being open. By setting up the external insulation assembly, internal insulation assembly, and shrinkage adjustment assembly, when using this safety inspection device for inspection, the vent is sealed to form a closed insulation cavity in low-temperature environments, and the vent is opened to allow air circulation, reducing the internal temperature. This reduces the temperature drift of the Hall current sensor due to the influence of the operating environment temperature, improves detection accuracy, and thus helps to improve the accuracy of leakage safety detection of central air conditioning outdoor units.

The invention provides a capacitance detection circuit for testing soil moisture content. The capacitance detection circuit comprises a soil moisture sensing electrode, a CV conversion capacitance detection circuit, an intelligent digital controller, a soil temperature detection circuit and a detection result output circuit, the soil moisture sensing electrode is electrically connected with the C / V conversion capacitance detection circuit; the CV conversion capacitance detection circuit, the soil temperature detection circuit and the detection result output circuit are electrically connected with the intelligent digital controller; the soil moisture sensing electrode transmits capacitance signals to the CV conversion capacitance detection circuit, the CV conversion capacitance detection circuit converts the changed capacitance signals into voltage signals and transmits the voltage signals to the intelligent digital controller, and the intelligent digital controller converts analog voltage signals into digital quantity through an internal ADC and directly outputs moisture content.

The invention relates to the technical field of wind power generation equipment, in particular to a shafting torque sensor suitable for a wind driven generator, which comprises a main shell and sealing side plates fixedly mounted on two sides of the main shell, and a static power supply coil is fixedly arranged in the main shell; according to the invention, friction waste heat generated in the operation of the bearing is recovered through an efficient heat pipe system, and is directionally transmitted to the rotating end signal processing module, so that a stable heat source is provided for the rotating end signal processing module in a low-temperature environment; the industrial problems that a fan sensor in an extremely cold area is difficult to start and the precision is reduced are solved, self-circulation utilization of energy is achieved, through the design of the structure of the rotating outer ring cooling cavity and the static flow deflector, strong turbulent flow is generated in the cooling cavity, the efficiency of transmitting bearing friction heat to cooling liquid is greatly improved, and local overheating is avoided. The heat pipes are used, so that efficient, long-distance and directional transmission of heat is achieved.

A 4P lens capable of reducing temperature drift, the lens comprises, from the object side to the image side, along the optical axis, a first lens P1, a second lens P2, a third lens P3, and a fourth lens P4, an aperture STO is arranged at the front end of the lens, the first lens P1 is a biconvex positive lens, the second lens P2 is a crescent-shaped positive lens with a concave surface facing the object side and a convex surface facing the image side, the third lens P3 is a crescent-shaped negative lens with a concave surface facing the object side and a convex surface facing the image side, and the fourth lens P4 is a crescent-shaped positive lens with a convex surface facing the object side and a concave surface facing the image side. The 4P lens of the present invention effectively solves the temperature drift problem of the optical lens, and can maintain the same image quality level as that at room temperature at high and low temperatures; at the same time, it can also achieve the technical effect of shortening the total length TTL of the lens and high imaging quality.

The invention discloses a thick-film resistor with high strain sensitivity and low temperature sensitivity and a preparation method thereof, and belongs to the technical field of functional materials, electronic elements and sensors. The preparation problem of the thick-film resistor with high strain sensitivity and low resistance temperature coefficient is solved. The preparation method comprises the following steps: weighing lead oxide, boron oxide and silicon dioxide, uniformly mixing, completely melting into molten glass, carrying out water quenching, and carrying out ball milling on the water-quenched glass slag to obtain lead borosilicate glass powder; weighing RuO powder and lead borosilicate glass powder, adding an organic carrier, mixing, adding into a three-roller grinder, and fully grinding to be fine and uniform, so as to obtain resistance paste; and coating a cleaned substrate with the resistance paste in a silk-screen printing manner, and in an air atmosphere, controlling the sintering peak temperature within the range of 750-950 DEG C and the heat preservation time of the sintering peak temperature within the range of 10-360 minutes to obtain the thick-film resistor with both high strain sensitivity and low temperature sensitivity.

The invention belongs to the technical field of medical breathing support equipment, and discloses a breathing machine gas path system and a use method, the system comprises an air input channel, an oxygen input channel, an air-oxygen mixing device and a controller; one end of the air-oxygen mixing device is provided with an air mixing inlet and an oxygen mixing inlet, and the other end is connected with a mixing output pipeline; the oxygen mixing inlet is connected with a Venturi tube arranged in the air-oxygen mixing device; the mixed output pipeline is connected with an anti-suffocation valve through a pipeline, the other end of the anti-suffocation valve is connected with a breathing connector through a pipeline, and the pipeline for connecting the anti-suffocation valve and the breathing connector is connected with an anti-suffocation exhaust port through a bypass; a first two-position three-way normally-closed valve is connected to the pipeline connecting the anti-suffocation valve and the mixed output pipeline through a bypass. The two-position three-way normally-closed valves are combined with the air-oxygen mixing cavity, so that air path modularization and standardization are achieved, the system structure is remarkably simplified, and the number of parts and connectors is reduced.

The utility model relates to low temperature drift long -delay power -on power -off time sequence circuit, it includes a plurality of power -on power -off time sequence unit using parallel architecture, power -on power -off time sequence unit includes power -on channel, power -off channel, comparator and control signal, power -off channel electricity connects external enable control module, power -on channel, power -off channel parallel access comparator negative input, comparator positive input accesses reference circuit, comparator output end connects corresponding control signal, the utility model discloses reasonable in design, compact structure and convenient to use.

The invention belongs to the technical field of inverters, and particularly relates to a circuit for realizing inductive current sampling of an inverter by using a current transformer, which comprises a T1, a controller and a Hall sensor, the driver and the PWM inverter are connected with the controller, the driver uses a Hall sensor as a current sensor of an inversion inductor Linv, acquires an inductive current and feeds back the inductive current to the controller to realize current closed-loop control, and by using a current transformer and a specially designed secondary circuit and combining with switching time sequence control of the inverter, the current closed-loop control of the inverter is realized. The reset of the exciting current of the current transformer is realized, the inductive current of the inverter can be sampled by using the current transformer, and as the current transformer has no temperature drift problem, fixed transformation ratio, low cost and relatively high bandwidth, the inversion inductive current sampling is realized by using the mode.

The application discloses a digital power distribution automation terminal, which comprises a cabinet, at least one main control unit arranged in the cabinet, a main control board, a microprocessor, a data storage and a clock chip, at least one analog quantity acquisition unit, a telemetry board, a voltage transformer, a current transformer, a filter circuit and an analog-digital converter, at least one switch quantity input unit, a remote signaling board, an optical-electric isolator, an overvoltage protection circuit and a data buffer, compared with the prior art, the problems of poor anti-interference, single communication and power failure of the traditional terminal are solved, and the reliability and field adaptability of the power distribution network operation are improved.

The invention discloses an IP core for an MEMS sensor CV detection circuit, the IP core comprises a C / V conversion circuit, a low pass filter LPF, a programmable gain amplifier PGA, an analog-to-digital converter ADC, a digital top layer module, a reference module REF and a temperature sensor, the C / V conversion circuit is connected with the low pass filter LPF, the low pass filter LPF is connected with the programmable gain amplifier PGA, the analog-to-digital converter ADC is connected with the digital top layer module, the reference module REF is connected with the analog-to-digital converter ADC, the digital top layer module is connected with the digital top layer module, and the temperature sensor is connected with the analog-to-digital converter ADC. The programmable gain amplifier PGA is connected with the analog-to-digital converter ADC, the analog-to-digital converter ADC is connected with the digital top layer module, the reference module REF is connected with the temperature sensor, and the temperature sensor is connected with the digital top layer module. And a temperature sensor is arranged in the IP core to carry out heat monitoring and temperature compensation on the circuit, so that the temperature excursion during the period is inhibited.

This invention relates to the field of magnetic levitation chiller technology and discloses an energy-saving variable frequency magnetic levitation chiller, including an evaporator, a condenser installed at the bottom of the evaporator, a connecting seat fixedly mounted at the end of the condenser, and a flow guiding component on the outer wall of the connecting seat. This energy-saving variable frequency magnetic levitation chiller recovers waste heat from the condenser cooling water to perform closed-loop constant temperature control on the magnetic levitation bearing, ensuring the bearing remains within its optimal operating temperature range. This avoids coil resistance drift, sensor temperature drift, and fluctuations in levitation stiffness under low-temperature conditions, improving the operational stability of the magnetic levitation bearing. Utilizing the residual heat of the heated cooling water for constant temperature treatment of the magnetic levitation bearing eliminates the need for additional electrical energy consumption for preheating and insulation. Building upon the inherent high efficiency and energy saving of magnetic levitation technology, this further reduces auxiliary energy consumption and improves overall energy efficiency.

A single chip full-bridge TMR magnetic field sensor includes: a magnetoresistive element and a bias current branch, wherein the magnetoresistive element is bridge-connected to form a full-bridge structure; the magnetoresistive element includes a free layer, a pinned layer and a bias current layer, wherein the bias current layer is connected to the bias current branch, and the bias current branch inputs a bias current to the bias current layer; the directions of the currents in the bias current layers of the magnetoresistive elements on adjacent bridge arms are opposite, and the directions of the currents in the bias current layers of the magnetoresistive elements on opposite bridge arms are the same. The present invention sets a bias current layer in the magnetoresistive element, and uses the bias current layer to change the magnetization direction of the free layer in the magnetoresistive element to achieve a sensitive response to an external magnetic field. The magnetic field sensor of the present invention can form a full-bridge structure on a single chip at one time, greatly reducing the difficulty and production cost of the single chip full-bridge magnetic sensor preparation process.

The invention relates to the technical field of laser application, and discloses a laser optical path thermal drift compensation device based on a TEC and a piezoelectric module, and the device comprises a negative electrode, a semiconductor laser chip, a positive electrode, a thermoelectric refrigerating unit, a ceramic chip, a lens, a telescopic and deformable piezoelectric module, and a fixed pedestal. The system further comprises a control module, a light path detection sensor, a high-voltage driving circuit, a position sensor and a temperature sensor. A dual active compensation mechanism is adopted, and cooperative control is carried out on two thermal deformation sources of a laser and a lens at the same time: a thermoelectric refrigerating unit is responsible for stabilizing a laser source and fundamentally inhibiting temperature drift; the piezoelectric module dynamically compensates lens side deformation, the comprehensive stability performance of the system is remarkably improved, and the compensation effect is remarkably superior to that of a single means. The temperature control precision of the thermoelectric refrigerating unit can reach + / -0.1 DEG C, the piezoelectric module has nanoscale resolution and millisecond response speed, thermal deformation can be tracked and counteracted in real time, and long-term stability of an optical path is ensured.

The present invention relates to a camera, comprising a lens (1), a base (2) mounted on the lens (1), and an imaging component (3) located at the lower side of the lens (1) and connected to the base (2), wherein the base (2) drives the imaging component (3) to move along the optical axis as the temperature changes. When the temperature of the working environment of the camera of the present invention changes, the base can drive the imaging component 3 to move along the optical axis as the temperature changes, thereby compensating for the temperature drift problem of the lens caused by the temperature change, thereby ensuring that the camera of the present invention has good imaging performance in both high and low temperature environments.