38results about How to "Increase time constant" patented technology

The invention relates to a method for preparing the start-up of an internal combustion engine (300) by means of a belt-driven starter generator (100), which has a stator winding (11) and a rotor winding (12), wherein the starter generator (100) is operated such that the generated torque thereof gradually increases over a duration of more than two rotor winding time constants. Current is fed to the stator winding (11) in such a manner that the generated torque gradually increases over a duration of more than two rotor winding time constants. Current is fed to the rotor winding (12) and, if an excitation current through the rotor winding (12) is below a lower threshold before the current feed, the stator winding (11) is fed with current before the excitation current is above an upper threshold. According to the invention, the belt of the starter generator is pretensioned prior to the actual starting process by means of actuation of the electrical machine and thus lurches, vibrations and noises that occur during the start-up of the internal combustion engine by means of a starter generator can be prevented.

The invention provides a controller, a chip and a method for eliminating current ripples of an LED (Light-Emitting Diode) driving system. The controller is electrically connected with an output end of an LED load and a first sampling resistor; the controller is configured to sample a voltage at an output end of the LED load and voltages at two ends of the first sampling resistor, and generate a first voltage signal according the voltage at the output end of the LED load and the voltages at the two ends of the first sampling resistors; the controller is used for generating a control signal according to the first voltage signal and voltages at the two ends of the first sampling resistor to control a conducting state of a power tube which is electrically connected with the LED load, so that the voltage magnitude of the first voltage signals is equal to that of a reference voltage, and the current ripples of the LED load are eliminated. Through adoption of the controller, the chip and the method, the LED current ripples are eliminated in a whole dimming process, and LED flickering caused by low-frequency jittering is avoided.

The invention is an amplifying circuit, containing an amplifier which has a positive input end, a negative end, a positive output end and a negative output end; a first input impedance connected between the negative input end and a first input signal; a second input impedance connected between the positive input end and the first input signal; a third input impedance connected between the negative input end and a second input signal; a fourth input impedance connected between the positive input end and the second input signal; a first output impedance connected between the negative input end and the positive output end; a second output impedance connected between the negative input end and the negative output end; a third output impedance connected between the positive input end and the positive output end; and a fourth output impedance connected between the positive input end and the negative output end.

A flux pump with a high temperature superconductor belongs to the flux pump field and comprises an iron yoke, magnetic poles, a temperature connector, a heater, independent windings, electric current connectors and a high temperature superconductive thin piece. A row of magnetic poles are arranged on both the upper surface and the lower surface of the frame-shaped iron yoke; an independent winding is wound around each magnetic pole; the high temperature superconductive thin piece is arranged between two rows of magnetic poles; a sensor is arranged on the high temperature superconductive thin sheet; electric current connectors are connected to ends of the high temperature superconductive thin piece; the temperature connector is connected to the iron yoke; and the heater is arranged in the flux pump and used for heating the high temperature superconductive thin piece. The invention has the advantages that: the work capacity can satisfy a magnet system with the resistance of a superconductive closed loop being within 100microohm, the work ripple within 10<minus6> is realized, and the flux pump can be applied to the superconductive magnetic resonance imaging system as well as the superconductive magnet systems with higher requirements for the stability of the magnetic field, such as a magnetic resonance spectrometer, and the like.

The invention discloses equipment for determining the proportion of gas in a gas mixture, comprising a measuring chamber, an ultrasonic wave source and an ultrasonic wave detector and a temperature sensor. The measuring chamber is provided with a chamber limiting structure containing a high heat conduction material, a gas inlet and a gas outlet, wherein the material is metal; the ultrasonic wave source and the ultrasonic wave detector are mounted to enable the ultrasonic wave source to transmit the ultrasonic wave to the ultrasonic wave detector through the measuring chamber; and the temperature sensor is mounted to enable the sensor to sense the temperature in the measuring chamber, wherein the measuring chamber has a tubular cavity with a radius r0 of 1-8mm so as the make the distance between gas in the measuring chamber and an inner wall of a tube, and the measuring chamber is designed so as to make the gas to be measured to tightly contact a rigid surface of an object with thermal inertia and good heat conduction, thus the heat can free move to a surrounding structure from the gas.

The present disclosure provides a fully differential switched capacitor integrator, including: an operational amplifier unit, including an operational amplifier for providing predetermined gain and bandwidth; a switched capacitor unit, including: a switched capacitor integration unit, connected across the input terminal of the operational amplifier Between the output terminal and the series branch including MOS switch Φ2 and capacitor C1, capacitor C3 is connected in parallel to the above branch, and a MOS switch Φ1 is also provided between the MOS switch Φ2 and capacitor C1 to connect to the reference voltage Vref, and Part of the positive feedback capacitor C2 is connected to the output terminal of the opposite polarity of the operational amplifier; the switched capacitor common-mode feedback unit is set between the positive output terminal and the negative output terminal of the operational amplifier, which is a six-switch four-capacitor structure; no overlapping clocks The generation unit generates the clock signal of the MOS switch. The fully differential switched capacitor integrator is insensitive to parasitics, has efficient area utilization and larger time constant.

The invention discloses a lower limit frequency expansion system of a capacitive sensor for non-contact measurement of the transient process of a transformer coil. The system includes a chip capacitance sensor, a frequency band expander, a measurement cable, an RC compensation matching circuit and a measurement system output port. The SMD capacitive sensor uses the principle of capacitive voltage division to sense the voltage signal of the transformer coil turns, and converts the high voltage signal into a low voltage signal. The frequency band expander realizes the expansion of the lower limit frequency of the capacitive sensor by increasing the input impedance of the measurement system. The RC compensation matching circuit can improve the high-frequency characteristics of the measurement system. After the expansion of the lower limit frequency, the capacitive sensor can measure the power frequency voltage and long-wave tail pulse voltage in the winding.

The invention relates to a thermal-insulating device of a thermal control system of an aerial camera. The thermal-insulating device comprises three stainless steel bolts and three thermal-insulating gaskets, which are symmetrically distributed along the axial direction, wherein a circular thermal-insulating pad is arranged between a first structure element and a second structure element; the thermal-insulating gaskets are arranged between an annular surface of each stainless steel bolt and a plane of the first structure element; the thermal-insulating gaskets, the first structure element, the thermal-insulating pad and the second structure element are fixedly connected through the stainless steel bolts; three symmetrically distributed bosses respectively extend from the first end face and the second end face of the thermal-insulating pad; the surfaces of three bosses at the first end face contact the plane of the first structure element; the surfaces of three bosses at the second end face contact the plane of the second structure element; a connection section of the stainless steel bolts penetrates through a through hole at the center of each boss; the boss structure is used for increasing the heat resistance and the contact heat resistance of the thermal-insulating pad; the heat of the first structure element is isolated through the thermal-insulating pad and the thermal-insulating gaskets; the heat is prevented from being directly transmitted to the second structure element from the first structure element; and the heat is also prevented from being conducted through the stainless steel bolts.

The invention relates to a parallel plate type antenna integrated optical waveguide omnidirectional electric field sensor and belongs to the electric field measurement technical field. Six LiNbO3 wafers are bonded together so as to form a square body, so that the integrated optical waveguide omnidirectional MZI (Mach Zehnder Interferometer) type omnidirectional electric field sensor provided by the invention can be formed; reflective integrated optical waveguide MZIs and modulation electrodes are fabricated on the inner surfaces of the front LiNbO3 wafer, the back LiNbO3 wafer, and the lower LiNbO3 wafer, and reflective films are formed on the end surfaces of the tail ends of the three wafers; metal films are fabricated on the outer surfaces of the upper LiNbO3 wafer, the lower LiNbO3 wafer, the front LiNbO3 wafer, the back LiNbO3 wafer, the left LiNbO3 wafer, and the right LiNbO3 wafer, so that three pairs of parallel plate antennas perpendicular to each other in pairs can be formed;and the parallel plate antennas and the modulation electrodes are connected together by connecting wires. The parallel plate type antenna integrated optical waveguide omnidirectional electric field sensor provided by the invention has the advantages of small size, high sensitivity and good low-frequency performance; and the receiving antennas have omnidirectionality and can detect electric fieldsin any direction.

The invention is an amplifying circuit, containing an amplifier which has a positive input end, a negative end, a positive output end and a negative output end; a first input impedance connected between the negative input end and a first input signal; a second input impedance connected between the positive input end and the first input signal; a third input impedance connected between the negative input end and a second input signal; a fourth input impedance connected between the positive input end and the second input signal; a first output impedance connected between the negative input end and the positive output end; a second output impedance connected between the negative input end and the negative output end; a third output impedance connected between the positive input end and the positive output end; and a fourth output impedance connected between the positive input end and the negative output end.

The invention discloses a trap filter which comprises a first integrating circuit, a unit gain anti-phase circuit and a second integrating circuit. An input terminal of the first integrating circuit is an input terminal of the trap filter, an output terminal of the second integrating circuit is an output terminal of the trap filter, a feedforward capacitor connects the input terminal with a feedback input terminal of the second integrating circuit, a feedback resistor and a feedback capacitor are in parallel connection between the output terminal and a feedback input terminal of the first integrating circuit, and a current control circuit connects the first integrating circuit with an anti-phase input terminal of an operational amplifier in the second integrating circuit. The invention also discloses a low pass filter, wherein an integrating circuit has a same structure of the above trap filter. An integrator has a large time constant, using a large resistor and a large capacitor can be avoided, and integration becomes simple.

The invention discloses a switched capacitor biasing circuit capable of reducing the power consumption of an operational amplifier. The switched capacitor biasing circuit comprises a P type current source tube biasing unit SCP and an N type current source tube biasing unit SCN. The biasing circuit utilizes the capacitor divider to transmit input signals quickly; the interference caused by the clock feedthrough effect is small; different biasing voltages can be generated without complex front-end bias generation circuit, thus the chip area is saved; and no direct current path is needed, so that no additional power consumption is increased. The switched capacitor biasing circuit can be widely applied to any operational amplification circuit working under certain switching frequency, and help the operational amplifier to achieve relatively low power consumption and quick signal establishment.

The invention provides a reconfigurable composite waveform generation circuit. The reconfigurable composite waveform generation circuit comprises a constant-current charging module, a threshold setting module and a logic judgment module, in two branches of the constant-current charging module, one branch generates an output waveform signal, and the other branch controls the duration of a direct-current level; the threshold value setting module compares the input waveform signal voltage value, the direct current level and the preset threshold value of each key node, and outputs a mark signal to the input end of the logic judgment module; and the logic judgment module performs logic judgment according to a mark signal input by the threshold setting module, and outputs a switch control signal to be fed back to the two charging branches in the constant-current charging module. The analog circuit, the threshold setting module and the simple logic control unit are combined, output of direct-current level, sawtooth wave and direct-current and sawtooth wave time division multiplexing waveforms is achieved, hardware cost is low, software configuration is not needed, simple and continuous adjustment can be achieved, and flexibility is high.