62results about How to "Improving Current Sensing Accuracy" patented technology

An exemplary circuit for sensing bi-directional current through a resistive element comprises a sampling unit, a charge transfer unit, and an amplifier. The sampling unit is switchably coupled to the resistive element and samples and stores a voltage corresponding to a current flowing through the resistive element. The charge transfer unit switchably connects the sampling unit to the amplifier such that the charge transfer unit and the amplifier convert the sampled voltage to a ground-referenced output voltage corresponding to the magnitude of the current and in accordance with the direction of the current through resistive element.

A power switching apparatus having a mechanism for improving current sense accuracy is provided. The power switching apparatus includes an output arranged to provide a sense current depending on a load current, a power switching device, a sense device, and a difference amplification device. The difference amplification device includes a first and a second amplifier input, at least one amplifier output connected to a current sense feedback loop arranged to reduce a difference of potentials between the first and the second amplifier input. A terminal of the power switching device and a terminal of the sense device are connected to an input and another terminal of the power switching device and a second terminal of the sense device are coupled to a first cross-coupling switching module.

A current-voltage conversion circuit of a current correcting unit having a current detecting terminal connected to a sense terminal of a power semiconductor device converts a sense current into a voltage and detects the voltage. A temperature detecting unit detects the ambient temperature of the power semiconductor device, and a correction unit performs a predetermined operation for correcting a characteristic difference due to the temperature on the basis of the detected temperature and outputs a control signal to a variable voltage source. The variable voltage source changes an output voltage on the basis of the output control signal and adjusts the potential of the sense terminal of the power semiconductor device on the basis of the changed voltage value. In this way, the characteristic difference between a main region and a sense region of the power semiconductor device is corrected.

The invention belongs to the field of a battery charge-discharge control technology and in particular provides a module controller of a lithium ion battery pack. The module controller comprises a power supply circuit, a micro controller unit (MCU), a charge-discharge control circuit, a current detection circuit, a temperature detection circuit and a light-emitting diode (LED) display circuit. The charge-discharge control circuit comprises a charge control unit and a discharge control unit, wherein the charge control unit and the discharge control unit are controlled to realize the charge-discharge selection of the lithium ion battery pack through the MCU; and the current detection circuit is used for detecting a bus bar current of the lithium ion battery pack. The module controller provided by the invention can detect voltage, current and temperature of the lithium ion battery pack in the charge-discharge process, guarantee the lithium ion battery pack to charge and discharge reasonably, and does not appear the phenomenon of damaging the battery life caused by overvoltage, overcurrent, short circuit, over-temperature and the like, so that the battery can work durably and effectively.

The invention discloses a polarization-depolarization current detection device for a crosslinked polyethylene medium-voltage cable. The device comprises a high-voltage loop module, a current measurement module and a data processing module. A high-voltage output end of the high-voltage loop module is used for connecting with a cable core of the crosslinked polyethylene cable and is used for producing cable polarization-depolarization current. An input end of an electric block is used for connecting with a metallic shield layer of the crosslinked polyethylene cable, and is used for detecting size of polarization-depolarization current of the crosslinked polyethylene cable. The data processing module is used for displaying and storing the polarization-depolarization current. Since the high-voltage loop module is adopted, the polarization-depolarization current is produced for the cable under different voltage grades, a high-voltage high-resistance relay unit is used for preventing the polarization-depolarization current from leaking, and meanwhile, a current detection module sealed by polyurethane and a microcontroller with a 24-digit A-D converter are adopted, and accordingly the whole device is high in antijamming capability, simple and convenient in testing process and high in current detection precision.

A first capacitor (2a) is connected between the output terminals of a rectification circuit (2) the input of which is an AC power source (1), and a three-phase inverter (3) in parallel with the first capacitor (2a), and the output of the three-phase inverter (3) is supplied to a motor (4). A second capacitor (3a) is connected in parallel with the input side of the three-phase inverter (3), a current detector (5) between the first capacitor (2a) and second capacitor (3a), and a third capacitor in parallel with the first capacitor (2a) slightly closer to the power source than to the current detector (5). Thus, the capacitance of the second capacitor (3a) is set as small as possible in such a range that a power device is not broken down by a surge voltage attributed to switching to suppress ringing, so that current is incorporated at a high speed with a high precision.

A solenoid driving apparatus that drives a solenoid by intermittently supplying an exciting current comprises a first current switching element turned ON and OFF so as to switchably allow and block passage of the exciting current supplied to the solenoid L, a loop current circuit 3 being connected to the first current switching element and passing a loop current caused by stored energy in the solenoid when the supply of the exciting current to the solenoid is stopped by the first current switching element, and a second current switching element being disposed between the solenoid and a junction of the first current switching element and the loop current circuit, and being turned ON and OFF so as to switchably allow and block passage of the exciting current and the loop current.

A PFC device includes at least one main switch, a converter that converts a current to be sensed in the PFC device into a voltage to be sensed, the PFC device generating a switch control signal to control the at least one main switch based on the current to be sensed, and a voltage sensor that receives the voltage to be sensed and an offset voltage, and senses the voltage to be sensed using the offset voltage to output a sense voltage. A method includes sampling the sense voltage, determining a sense value of the offset voltage based on a sampling result, and calculating the current to be sensed based on a difference between the sense voltage and the sense value.

The invention provides a transformer substation tripping and closing loop accurate monitoring device and method. The device comprises a tripping and closing loop, a test loop, a linear power amplifier, a DA module, an FPGA, a power resistor, a first path signal amplification module, a first path AD acquisition module, a Hall sensor, a second path signal amplification module, a second path AD acquisition module, a temperature and humidity sensor and an input module. According to the invention, the tripping and closing loop current of the transformer substation is accurately monitored, the tripping and closing states can be recognized, the situation that the tripping and closing loop current is abnormally increased due to line aging and other reasons possibly occurring in long-term operationof the transformer substation can be monitored, fault points are rapidly positioned, and safe operation of a power grid is effectively guaranteed.

The invention discloses an open-type current transducer and a control method thereof. The open-type current transducer comprises a closed-loop control module and an exciting module; the exciting module comprises an exciting vibrator, an exciting unit connected with the exciting vibrator, and a direct current magnetic bias detection unit which is connected with the exciting unit; a fluxgate technology is adopted for the exciting module, and direct current magnetic bias signals are output through a magnetic modulation technology; the exciting vibrator outputs alternating voltage signals with a preset frequency to the exciting unit to excite the exciting unit to generate a target exciting magnetic field, the target exciting magnetic field is used for detecting a direct current bias magnetic field generated by to-be-tested current in a to-be-tested circuit, and outputting the direct current magnetic bias signals corresponding to the direct current bias magnetic field through the direct current magnetic bias detection unit, and the closed-loop control module is connected with the direct current magnetic bias detection unit. According to the open-type current transducer and the control method thereof, alternating current and direct current are precisely detected, and the current detection precision of the open-type current transducer is improved.

The invention discloses a performance testing device and a measuring method for an oil inlet metering valve of a common rail pump. The oil inlet metering valve, an inlet pressure sensor, an inlet temperature sensor, a first outlet pressure sensor and a second outlet pressure sensor are arranged on a valve block. By adopting the device, measurement including current flow characteristics, internal leakage and opening and closing delay time can be effectively realized. Pressure difference closed-loop regulation of inlet pressure and outlet pressure is realized in a real sense, and the influence of unstable pressure difference on a measurement result in a measurement process is avoided; moreover, a proportional servo valve is adopted for pressure difference regulation, so that the testing rhythm is greatly increased. A Hall current sensor is adopted for current detection of the oil inlet metering valve, so that an actual current waveform can be measured, a current effective value can be calculated, and the current detection accuracy is increased. The inlet temperature of the oil inlet metering valve is controlled, so that the electrical parameters of the oil inlet metering valve, the characteristics of test oil and the like are kept in a stable state in the measurement process.

A first capacitor (2a) is connected between the output terminals of a rectification circuit (2) the input of which is an AC power source (1), and a three-phase inverter (3) in parallel with the first capacitor (2a), and the output of the three-phase inverter (3) is supplied to a motor (4). A second capacitor (3a) is connected in parallel with the input side of the three-phase inverter (3), a current detector (5) between the first capacitor (2a) and second capacitor (3a), and a third capacitor in parallel with the first capacitor (2a) slightly closer to the power source than to the current detector (5). Thus, the capacitance of the second capacitor (3a) is set as small as possible in such a range that a power device is not broken down by a surge voltage attributed to switching to suppress ringing, so that current is incorporated at a high speed with a high precision.

The present invention discloses a current detection method of a one-phase inversion grounding device. The main body of the device is a one-phase inverter which is connected between the neutral point of a power distribution network and the ground. In the condition of the normal operation of an electric system, two power frequency current with the same injection amplitude and different phase angles are injected into the neutral point of the power distribution network at different times through an inversion circuit, the neutral point voltage value when the current is injected twice is measured in real time, and the power distribution network grounding parameters (power distribution network equivalent impedance and equivalent electromotive force) are calculated, so that the amplitudes and the phases of the power distribution network fault arc extinguishing and the three-phase imbalance compensation current. The current is injected to the neutral point to inhibit the grounding fault arc and maintain the three-phase voltage balance. The current detection method of the one-phase inversion grounding device can be enforced when the system is normally operated so as to effectively avoid the influence of the transient process on the detection precision at the occurrence of the grounding fault; and moreover, the current detection method of the one-phase inversion grounding device only needs to inject current into the neutral point twice to realize the current detection, with high timeliness and simple realization.

A stabilized power supply-use device of the present invention, which is mounted on a switching power supply, is an IC into which power transistors, a control circuit for controlling a base current of the power transistors, and other electronic components are formed, and an overcurrent detecting resistor connected in series with the power transistor is realized by a resister provided externally to the IC. Therefore, as compared to the overcurrent detecting resistor being made up of aluminum wiring patterns inside the IC, the overcurrent detecting resistor of the present invention dramatically decreases variations in value of resistance, whereby it is possible to improve an accuracy of voltage detection and to arbitrarily set a value of resistance. This eliminates the need for a needlessly increased input power capacity in a test based on safety standard and other tests, thereby enabling a switching power supply manufactured at a lower cost.

An integrated circuit (IC) comprises a switch transistor, a gate driving circuit, a currents sensing circuit, a voltage drop adjusting circuit and a charge release circuit. The switch transistor is connected between an input port and an output port of the IC, receives an input signal from a power supply, and provides the input signal, as an output signal, for an output port; the current sensing circuit detects a current through the switch transistor; the grate driving circuit uses a control signal to drive the switch transistor; when the current through the switch transistor is low, the voltage drop adjusting circuit is activated; the voltage drop adjusting circuit controls the control signal to increase the voltage of the switch transistor; and when the power supply is disconnected, the charge release circuit transfer superfluous charges in the input end of the IC to the ground.

The invention discloses a high-precision portable front-end device for electrochemical detection. The device comprises a forward voltage follower circuit, an RE-CE electrode based on the forward voltage follower circuit, a current-voltage conversion circuit, a WE electrode based on the current-voltage conversion circuit and a three-ring opposite vertex cross negative feedback amplifier. Accordingto the three-ring opposite vertex cross negative feedback amplifier, an output node of a negative feedback circuit formed by A1 is connected with an output node of a negative feedback circuit formed by A2, and the two nodes are combined to form an opposite vertex ring; an output node of the negative feedback circuit formed by A2 is connected with an in-phase input node of the negative feedback circuit formed by A3, an anti-phase input node of the negative feedback circuit formed by A3 is connected with an anti-phase input node of the negative feedback circuit formed by A2, and the two nodes are combined to form a cross ring. By means of the arrangement, compared with a traditional amplifying circuit, the noise level is lower, the signal bandwidth is larger, and the testing precision of a traditional electrochemical detector is improved.

A first condenser (2a) is connected between output terminals of a rectifier circuit (2) which receives an AC power (1) as an input, and a three phase inverter (3) is connected in parallel with respect to the first condenser (2a), and output of the three phase inverter (3) is supplied to a motor (4), and a second condenser (3a) is connected in parallel to the input side of the three phase inverter (3), and a current detector (5) is connected between the first condenser (2a) and the second condenser (3a), and a third condenser is connected in parallel to the first condenser (2a) at a position slightly power side with respect to the current detector (5), and the capacitance of the second condenser (3a) is determined as small as possible within the range in which power devices are not destroyed by surge voltage due to switching, therefore, ringing is suppressed, and taking of current is performed rapidly and with high accuracy.