63results about How to "Improving Current Sensing Accuracy" patented technology

A battery pack of a series combination of cell units is connected with a motor drive control circuit to drive a traction motor for a vehicle. A current sensor senses a discharge / charge current of the battery pack, and a voltage detecting circuit senses a voltage between two separate points in the series combination of the battery pack. A memory section stores a reference voltage drop quantity representing a decrease in voltage during a predetermined time interval between the two separate points. An offset detecting section compares an actual voltage drop quantity sensed by the voltage detecting circuit, with the reference voltage drop quantity, thereby detects a non-discharge / charge-current state of the current sensor, and reserves an output of the current sensor, as an offset quantity upon the detection. A correcting section corrects a sensed value of the discharge / charge current with the reserved offset quantity.

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 discloses a detection range-adjustable current detection circuit and method. The circuit comprises a hall current sensor, a digital signal processor and a range adjusting circuit, wherein the hall current sensor is used for collecting detection current signals; the digital signal processor is used for judging the current interval where the values of the detection current signals are positioned; the range adjusting circuit is used for adjusting the detection range of the detection current signals according to the judged current interval. According to the detection range-adjustable current detection circuit and method, the current detection precision of the current detection circuit can be improved.

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 relates to a program control AC constant current source system, and the system comprises a constant current source circuit module. A single-chip microcomputer unit of the constant current source circuit module outputs two complementary pulse width modulation drive signals for controlling a DC-AC full-bridge inverter circuit, and carries out the time sequence control of the two complementary pulse width modulation drive signals. The output end of a DC conversion module is connected with the DC-AC full-bridge inverter circuit, and the output end of the DC-AC full-bridge inverter circuit is connected with a filter circuit. A current-increasing transformer carries out the voltage reduction and current increasing of a high-voltage small current outputted by the filter circuit, and then supplies the high-voltage small current to a load circuit. A voltage-adjusting type self-coupling transformer is located between the constant current source circuit module and the current-increasing transformer, and the duty ratios of the pulse width modulation drive signals are mainly controlled to be 20%-80% through changing the number of turns of a secondary coil of the voltage-adjusting type self-coupling transformer. The system also comprises a current feedback circuit module for detecting the size of a current of the load circuit. The system is high in response speed and is high in precision.

The invention discloses a current sensor and a multi-flux balancing control circuit thereof. According to the current sensor and multi-flux balancing control circuit thereof, the multi-flux balancingcontrol circuit comprising an exciting flux balancing module and an AC-DC flux balancing module is adopted in the current sensor, the exciting flux balancing module generates an exciting compensationmagnetic field according to a detected interfering magnetic field, magnetic flux of a magnetic field, formed by superimposing the exciting compensation magnetic field and the interfering magnetic field, passing through a plane perpendicular to its magnetic induction lines is zero; the AC-DC flux balancing module generates an AC-DC compensating magnetic field according to a detected A flux signal and a DC magnetic bias signal output by means of an excitation module, and magnetic flux of a magnetic field, formed by superimposing the AC-DC compensating magnetic field, a DC magnetic bias magneticfield and an AC magnetic field, passing through a plane perpendicular to its magnetic induction lines is zero, thereby eliminating the magnetic field interference generated by the excitation module, realizing precise detection of the alternating current and the direct current, improving the current detection precision of the sensor, and reducing the production cost of the sensor.

The invention discloses an embedded open-loop Hall current sensor for an intelligent contactor and belongs to the field of Hall current sensors. The embedded open-loop Hall current sensor specificallycomprises a circuit board, a gasket, Hall elements, a multi-air-gap magnetic ring and a frame which are all packaged in a magnetic shielding assembly; the magnetic shielding assembly is fixed on an end surface of the intelligent contactor; six bang-shaped grooves with the same shape are symmetrically distributed in the frame; an air gap is reserved between every two grooves; the multi-air-gap magnetic ring is composed of six completely-identical distributed magnetic cores; the magnetic cores are embedded into the bang-shaped grooves of the frame respectively through tight fit; the Hall elements are inserted into the air gaps reserved in the magnetic ring on the frame; the four pins of each Hall element are welded onto the circuit board; the four pins are led out from the circuit board soas to extend into a magnetic shielding cover. With the embedded open-loop Hall current sensor of the invention adopted, under a premise that the length of the air gaps is fixed, the magnetism gathering effect of the magnetic ring is effectively enhanced, and a flux leakage amount at the air gaps is reduced.

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.

The invention relates to a frequency conversion apparatus and a frequency conversion method. The frequency conversion apparatus comprises a rectifier used for transforming inputted alternating current (AC) into direct current (DC); an intermediate DC part used for stabilizing the DC transformed by the rectifier, and provided with a current detection resistor; a current detection component used for collecting and amplifying differential signals reflecting the voltage difference between two ends of the current detection resistor so as to detect the current passing through the current detection resistor; a controller used for calculating each reconstructed AC phase current in dependence on the detected current of the current detection resistor; and an inverter used for converting the DC stabilized by the intermediate DC part into AC in dependence on the calculated reconstructed AC phase currents. The scheme can improve the current detection precision in the frequency conversion apparatus, so as to increase AC phase reconstruction precision and improve frequency converter control performance.

The invention relates to a strong anti-interference wide-range permanent magnet synchronous motor current sampling circuit. The strong anti-interference wide-range permanent magnet synchronous motor current sampling circuit comprises a Hall current sensor unit, a fully differential amplifier conditioning unit, a Delta-Sigma modulation unit and an MCU micro control unit. The Hall current sensor unit converts the acquired current of the alternating current permanent magnet synchronous motor into an alternating voltage signal; the fully differential amplifier conditioning unit conditions the alternating voltage signal to obtain a differential voltage signal; the Delta-Sigma modulation unit is used for converting the differential voltage signal into a high-speed single-bit data stream; and theMCU micro-control unit restores the high-speed single-bit data stream into an original current waveform. According to the sampling circuit provided by the invention, on the basis that the phase current detection precision of the alternating current permanent magnet synchronous motor can be improved, wide-range sampling is realized when the alternating current permanent magnet synchronous motor runs at low frequency until overloading, and strong anti-interference capability is achieved, so that rapid, accurate and dynamic control of the alternating current servo control system on the alternating current permanent magnet synchronous motor is improved, and the reliability and safety of the system are improved.

The invention relates to a current detecting circuit for overload protection and overcurrent protection of a brushless direct current motor. The current detecting circuit for the overload protection and the overcurrent protection of the brushless direct current motor comprises a single-chip microcomputer, a current sampling circuit and a power module, and the current sampling circuit is connected with the single-chip microcomputer and the power module respectively. The current detecting circuit for the overload protection and the overcurrent protection of the brushless direct current motor has the advantages that the influences of magnetic core saturation brought by a current transformer are avoided, the current detection precision is high, the circuit structure is simple, cost is low, and the current detecting circuit for the overload protection and the overcurrent protection of the brushless direct current motor is easy to implement and can achieve the overload protection and the overcurrent protection of the brushless direct current motor.