265 results about "Voltage transducers" patented technology

The invention discloses a driver controller detection system, which comprises an acquisition module, an acquisition module, a processing module, an identification module, a judgment module, an analysis module and a generation module, the acquisition module captures contact information and electromagnetic interference data of contacts in real time by means of a high-dynamic voltage sensor and a broadband EMC probe; the acquisition module is triggered by a locomotive signal and records dynamic working condition data; the processing module aligns the data, performs denoising and extracts fault parameters; the identification module scans the voltage waveform and judges the transient contact failure; the judgment module monitors EMC data and compares an instruction position, and judges misoperation; the analysis module analyzes fault association, judges a composite type and triggers an alarm; the generation module generates a detection report and a log. According to the system, a multi-dimensional monitoring network is constructed under a dynamic working condition, data reliability is guaranteed, faults are accurately identified, a compound fault source is positioned, and the safety and stability of locomotive operation are improved through risk grading early warning and automatic reporting.

An electronic device may include a transmitter coupled to an antenna over a signal path that runs through a front end module. The front end module may include a power amplifier disposed on the signal path. The front end module may include first, second, and / or third signal attenuators disposed on the signal path between an input of the amplifier and the transmitter. The front end module may include a voltage sensor that measures a bias voltage of the amplifier, a temperature that measures a temperature of the amplifier, and / or an impedance sensor that measures an impedance of the antenna. The first signal attenuator may be adjusted based on the measured bias voltage, the second signal attenuator may be adjusted based on the measured temperature, and the third signal attenuator may be adjusted based on the measured impedance to mitigate changes in the amplifier as operating conditions change over time.

In disclosed embodiments, a voltage sensor of a computing device is configured to determine a voltage level of a supply voltage provided by a power supply to processor circuitry. Comparator circuitry may perform a comparison operation that compares the determined voltage level to a threshold. A temperature sensor may determine a temperature of at least a portion of processor circuitry. Power control circuitry may initiate a power management operation to adjust voltage margin based on a result of the comparison operation. Additionally, the power management circuitry may control the comparator circuitry to impose an offset on the comparison operation. The power control circuitry may determine a magnitude of the offset based on a pre-determined effect of the determined temperature on voltage margin parameters for at least a portion of the processor circuitry.

The invention belongs to the technical field of power grids, and particularly relates to a hydrogen fuel cell grid-connected inverter fault test and ride-through method. Comprising the following steps: S1, simulating three-phase symmetrical voltage drop, inter-phase voltage drop and single-phase voltage drop of a power grid through a low-voltage fault generation device; s2, collecting the voltage of a power grid through a high-precision voltage sensor, and when the voltage of the power grid drops, judging whether the system needs to carry out low-voltage ride through at the moment according to a distributed energy low-voltage ride through curve; and S3, when the system needs to carry out low-voltage ride-through, a dual-second-order generalized integrator pre-filtering phase-locked loop (DSOGI-PLL) is combined with grid-connected point voltage full-feedback compensation, negative-sequence components generated by symmetric and asymmetric drop of the power grid voltage are eliminated, and current impact suppression and negative-sequence current elimination are realized. The problem of power grid synchronization under the condition of power grid voltage drop is finally solved.

The invention relates to the technical field of power equipment state monitoring, and provides a switch cabinet state intelligent detection method and system based on multi-sensor fusion, and the method comprises the steps: obtaining state data corresponding to a switch cabinet through a temperature sensor, a vibration sensor, a partial discharge sensor, a current sensor and a voltage sensor which are disposed in the switch cabinet; inputting the obtained state data into a preset data preprocessing module, performing denoising processing and normalization processing on the state data, obtaining preprocessed multi-source data, and generating a multi-dimensional feature vector; inputting the multi-dimensional feature vector into a preset hierarchical fusion model, carrying out feature layer fusion on the multi-dimensional feature vector to obtain an intermediate fusion feature, combining historical operation data and historical fault data of the switch cabinet, carrying out decision-making layer weighted fusion on the intermediate fusion feature to generate a comprehensive state feature vector, and outputting the comprehensive state feature vector. And triggering a corresponding early warning system or a fault alarm system.

Certain aspects of the present disclosure generally relate to electronic circuits and, more particularly, to techniques and apparatus for signal amplification. One example apparatus generally includes: a current sensor configured to sense a current associated with an amplifier; and a voltage sensor configured to sense a voltage associated with the amplifier. The apparatus may also include a logic circuit configured to: detect a first over-current condition associated with the amplifier based on the current; detect a first over-voltage condition associated with the amplifier based on the voltage; and adjust an amplification gain to yield a first adjusted gain level for an input signal based on detection of the first over-current condition and the first over-voltage condition, wherein the amplifier is configured to amplify the input signal based on the first adjusted gain level.

A plasma processing apparatus includes a radio-frequency (RF) power supply; a pair of plasma electrodes, and a matcher disposed between the pair of plasma electrodes and the RF power supply. The matcher includes an RF feed line supplied with RF power from the RF power supply; a ground line; a first load line connected to one of the plasma electrodes; a second load line connected to the other of the plasma electrodes; an impedance matching circuit connected to the RF feed line, the first load line, the second load line, and the ground line, and including variable reactance elements; an RF sensor that is provided in the RF feed line and detects the RF power; a voltage sensor that detects a first peak value; and a matcher controller that controls the variable reactance elements by inputting detected values from the RF sensor and the voltage sensor.

The invention discloses a ground station multipath load intelligent power distribution system and a power distribution method. The system comprises a power supply module, a Hall voltage sensor, a single-chip microcomputer, an AD acquisition module, an input / output relay, a Hall current sensor and a master control module. Data receiving, transmitting, analyzing, storing and updating of input voltage and load current are achieved through the input measurement and control module and the load measurement and control module. Through acquisition and judgment of the main control module, the functions of input / load multichannel on-off execution, fault reporting of open phase, overvoltage, undervoltage and the like are realized, and an intelligent power distribution strategy is generated. By using the design method provided by the invention, the design cost can be effectively reduced; the load can be automatically distributed to a three-phase power supply; the method can achieve the quick and simultaneous power-on and power-off of multiple loads in a short time, can record a load curve, updates a power distribution strategy in time, and can adapt to various power distribution scenes.

The embodiment of the invention relates to the technical field of capacitor detection, in particular to a capacitor open-circuit fault detection method, a battery system and a storage medium. According to the embodiment of the invention, the bus voltage and the candidate voltage of the candidate capacitor are sampled by using the existing voltage sensor, the candidate ratio is determined according to the bus voltage, the candidate voltage of the candidate capacitor and the target number, and the reference ratio is determined according to the target number and the number threshold value related to the battery system. And finally, a fault detection result of the candidate capacitor is obtained based on the candidate ratio and the reference ratio, so that the open-circuit fault of the single capacitor can be rapidly and accurately detected, a complex algorithm, accurate current sampling and addition of any additional hardware are not needed, the cost is low, the calculated amount is small, the requirement on the performance of a controller is low, and other control logics cannot be influenced.

The invention relates to a measuring transducer arrangement (1) with an annular carrier element (7), which is made of an electrically conductive material, and a voltage sensor (3), which comprises a conductor film (15) arranged on the carrier element (7) and having a first layer (23) and a second layer (24). The first layer (23) has at least one strip-like measuring electrode (27), which is connected to an electrical measurement potential. The second layer (24) has at least one strip-like earth electrode (28), which is connected to an electrical earth potential. The carrier element (7) is connected either to the measurement potential or to the earth potential.

The invention belongs to the field of aerospace electronic measurement, and provides an inductance type proximity sensor resolving method and system based on an improved DFT algorithm, and the method comprises the steps: applying a sine excitation signal of an excitation frequency; synchronously acquiring a sine excitation signal and a sensor response signal of the output end of the proximity sensor; an improved DFT algorithm is adopted, the amplitude and the phase under the excitation frequency are extracted, and the voltage vector relation among the excitation voltage, the output voltage of the sensor and the complex impedance of the sensor is constructed; the inductance value and the parasitic resistance value of the proximity sensor are calculated through triangular transformation and calibrated, and the calibrated inductance value is obtained. According to the method, the reliability is high, complex electronic hardware is not needed, the development cost is low, the inductance value of the sensor is obtained on a DSP28335 platform based on the improved DFT algorithm, the precision reaches 0.15 mH, and the consumed time of single-path calculation does not exceed 2 ms. The expansion is easy, and the newly increased time is not more than 1ms when one path of sensor is newly increased.

The utility model relates to a pole switch with integrated coupler and capacitive voltage sensor, including, first electric capacity CH is connected with power A, and second electric capacity CL is connected with first electric capacity CH, one input of high pass filter and low pass filter is connected with one end of second electric capacity CL respectively, the output of high pass filter is connected signal coupler, the utility model promotes long -term reliability and measurement accuracy: in traditional scheme, because voltage sensor and communication coupler are separate, are easily affected by outside environment and lead to system unreliable or measurement inaccuracy. And the utility model through adopting low pass filter isolation high frequency signal ensures voltage sensor normal work, and uses high pass filter to guarantee signal coupler normal operation, effectively prevented high frequency communication signal to voltage sampling loop's crosstalk and strong power frequency voltage to coupler's damage, improved the long -term reliability and voltage measurement accuracy of system.

The utility model relates to a negative pressure weighing chamber FFU group control system and a power supply module, a main power supply module PWR1 selects a linear power supply and stably supplies power to an external function board module, the positive electrode of the main power supply module PWR1 is connected with the input end of an electronic switch SW1 through a wire, and the negative electrode is connected with the negative electrode of a function board; the redundant backup power supply module PWR2 adopts a storage battery, and the negative electrode is connected with the negative electrode of the function board. The voltage sensor VT is an INA219 sensor and accurately measures PWR1 voltage, the microcontroller selects STM32 and controls on-off of the electronic switches SW1 and SW2 according to sensor information, the electronic switches SW1 and SW2 select N-channel MOS field effect transistors, and a 1N4007 protection diode is further arranged to prevent current reversal. After the system is initialized, the PWR1 supplies power normally, and the PWR2 is switched to quickly when the voltage is abnormal, so that uninterrupted power supply is ensured, and the system has the advantages of high stability, accurate monitoring, quick switching and the like, and meets the strict requirements of the negative pressure weighing chamber.

The problem to be solved by the present invention is to provide a spatter detection method that can detect the generation of spatter using existing sensors without resetting the voltage detection line near the electrode chip. To solve the above problem, in a spot welding method using a spot welding apparatus, pressure is applied to a clamped workpiece using an electrode chip, and a pulsed welding current generated by repeated cycles of alternating energization control and energization pause implemented by a welding power supply circuit is provided to the workpiece. Simultaneously, during energization control, the welding current is maintained within a set peak current range during the peak maintenance interval. The spatter detection method includes: a step of acquiring the average value of the voltage detection value Vpv of the voltage sensor during the peak maintenance interval of each of the aforementioned cycles; and a step of determining the presence or absence of spatter generation based on the difference between the average value of the voltage detection value Vpv during the peak maintenance interval of the Nth cycle and the average value of the voltage detection value Vpv during the peak maintenance interval of the (N-1)th cycle.

The invention provides a low-voltage equipment management system and method for a power distribution network. The low-voltage equipment management system for the power distribution network comprises a terminal sensing layer, an edge computing node and a cloud management platform. The intelligent sensing terminal at least comprises a voltage sensor, a current sensor, a temperature sensor and a vibration sensor; the RFID tag is an ultrahigh frequency passive tag and is used for writing equipment identity information; the Bluetooth gateway is used for collecting environment temperature and humidity and dust concentration data; the edge computing node comprises an embedded edge gateway for multi-interface communication, a local database and an edge algorithm module; and the cloud management platform comprises a digital twinning engine for constructing a three-dimensional digital twinning body of the equipment, a health degree evaluation module, an operation and maintenance scheduling module and a visual interface. The invention provides a low-voltage equipment management system and method for a power distribution network, and aims to solve the technical problems of single data acquisition and high maintenance cost of low-voltage equipment in the prior art.

The present application provides a kind of more accurately determine the state of solar panel technology.Can be mounted on the solar system of mobile vehicle has: solar panel;Current sensor, which measures the current value output from solar panel;Voltage sensor, which measures the voltage value output from solar panel;And control unit, based on the difference between the first current value and the second current value, determine the state of solar panel, the first current value is on the I-V curve indicating the correlation of current value and voltage value within the pre-specified period, when differential conductance changes from the value above the pre-specified first threshold to the value less than the first threshold, the current value corresponding to the voltage value at this time, i.e. the first voltage value, the second current value is on the I-V curve, when differential conductance changes from the value less than the first threshold to the value above the first threshold, the current value corresponding to the voltage value at this time, i.e. the second voltage value.

The application belongs to the technical field of signal amplifiers, and particularly relates to a signal amplification adapter for power grid upgrading and reconstruction, which comprises a power module, a filtering module, an input adjusting module, a three-phase and zero sequence operational amplifier module, a phase detection and correction module and an output protection module. The input adjusting module comprises a filtering unit, which is connected with A-phase output, B-phase output, C-phase output and zero sequence signal respectively for filtering out high harmonic interference. The phase detection and correction module comprises a phase detection unit and a phase correction unit. The input of the phase detection unit is connected with the output of the three-phase and zero sequence operational amplifier module for detecting phase difference. The input of the phase correction unit is connected with the output of the phase detection unit for correcting phase difference. Through use of the application, matching work of electronic voltage sensors and electromagnetic electric meters under voltage characteristics in Southeast Asia can be realized.

The invention relates to a multi-range voltage sensor and a voltage measuring method thereof, and belongs to the technical field of sensors. Wherein the power supply unit comprises two isolated voltage-stabilizing power supply sub-units, and the active noise reduction unit is connected between the high-voltage side voltage-stabilizing power supply sub-unit and the processing unit for noise reduction; the voltage dividing unit is used for accessing to-be-measured high voltage and dividing the high voltage to output a voltage sampling signal; the processing unit is used for processing the voltage sampling signal; the V / I conversion unit is used for converting the voltage sampling signal into a current sampling signal according to a specified proportion; the fluxgate detection unit is used for detecting the current value of the current sampling signal so as to output a current detection signal, and the current value reflected by the current detection signal and the current value reflected by the current sampling signal are in a first fixed proportion; the sampling unit is used for converting the current detection signal into a voltage detection signal according to a second fixed proportion and outputting the voltage detection signal. The high voltage to be measured is measured based on the working principle of the fluxgate, and the voltage measurement precision can be remarkably improved.

The embodiment of the application relates to the technical field of electronics, in particular to a PWM signal generation system, which comprises a PWM generation circuit and a clock cycle analysis circuit. The embodiment of the application dynamically adjusts the number of buffers of an initial delay line, and adaptively determines a target number according to a delay signal state, thereby greatly shortening the calculation period of the total number of buffers in the PWM generation circuit and avoiding the time-consuming iterative calculation in the traditional scheme. In addition, the logic of deriving the total number of buffers based on the target number can realize accurate matching of the delay time of the buffer and the clock cycle, improve the control accuracy of the PWM duty cycle by combining the fine delay processing of the delay unit on the PWM signal, and make up for the defects of insufficient accuracy of the traditional circuit. The system also integrates a temperature sensor and a voltage sensor, and the microprocessor can correct the deviation of the delay time of the buffer in combination with the environmental parameters, enhance the stability of the system under complex working conditions, and widen the applicable scenarios of the system in the technical field of electronics.

In a charging device having a first switch capable of interconnecting the outputs of a plurality of power converters, welding of the first switch can be detected without providing a dedicated mechanism. [Solution] The charging device of the present invention comprises a plurality of power converters, a first switch capable of interconnecting the outputs of a pair of the plurality of power converters, a plurality of second switches connected respectively between the output of each of the plurality of power converters and each of a plurality of charging ports, a voltage sensor detecting the voltage values ​​of a plurality of voltage lines connecting the outputs of the plurality of power converters and the plurality of second switches, and a fault detection unit that detects a welding fault in the first switch when the difference in voltage values ​​of a pair of voltage lines connected to the outputs of the pair of power converters detected by the voltage sensor is greater than a threshold value when the outputs of a pair of power converters outputting DC voltage are connected to each other by the first switch.

To accurately simulate the detection signal of a voltage sensor. [Solution] A voltage sensor simulation circuit comprising: a power converter having phase PWM control signals for each phase, each containing an arm element, between a positive bus and a negative bus; a calculator that calculates the arm voltage for each phase output from the arm of each phase in accordance with the PWM control signal for each phase, using the polarity of the output current of each phase of the power converter, the DC bus voltage between the positive bus and the negative bus, and the on voltage between the main terminals of the arm element; and a generation circuit that generates a sensor simulation signal for each phase, which is a signal that simulates the detection signal for each phase output from a voltage sensor that detects the output voltage of each phase of the power converter, by adding or subtracting the arm voltage of each phase.

The invention discloses a photovoltaic array short-term power prediction method, and relates to the field of photovoltaic power generation prediction and energy management. The method includes the steps that current and voltage values of a photovoltaic array power generation loop are collected in real time through a current and voltage sensor, power generation power data are obtained through calculation and serve as an original data set, and the original data set is divided into a training set, a verification set and a test set; the method comprises the following steps of: preprocessing an original data set by adopting a method of combining variational mode decomposition and singular spectrum analysis noise reduction, and optimizing parameters by using a spider bee optimization algorithm to obtain noise-reduced generation power data; by introducing a fractional order norm and energy entropy secondary screening mechanism, the screening precision of a sparse probability attention module on a key query sequence is optimized, a DESform model is constructed, the sparsity and the information concentration degree of key query features are quantified, and then the weight of the key features is calculated. According to the method, the problems that the photovoltaic power trend is complex, fluctuation is random and the like are difficult to predict are effectively solved.

The application discloses a kind of EKF-based photovoltaic inverter IGBT thermal network online parameter identification method, comprising the following steps: S1, using third-order Cauer network, the heat transfer path of IGBT module establishes IGBT thermal network discrete state space model;S2, based on IGBT thermal network discrete state space model, design EKF algorithm for thermal parameter joint estimation for the synchronous estimation of state and parameter;S3, using current sensor and voltage sensor real-time acquisition IGBT current waveform, voltage waveform, and preprocessing;S4, in the embedded microcontroller of photovoltaic inverter, with fixed sampling period, EKF algorithm is operated, time update and measurement update are sequentially executed in each cycle, and the optimal estimation value of current time updated thermal parameter and junction temperature estimation value are output.The application can track the actual thermal characteristics of IGBT in real time, solve the parameter mismatch problem, and realize dynamic online identification of thermal parameters.

A fuel system for a machine with an engine is configured to monitor a voltage of a power supply of the machine based on voltage data acquired by a voltage sensor where the power supply is configured to receive power from an alternator driven by the engine, compare the voltage to a voltage threshold, and control an electronic lock off valve associated with a fuel tank such that the electronic lock off valve is (i) closed to prevent a fuel from being provided from the fuel tank to the to the engine in response to the voltage being less than the voltage threshold and (ii) open or openable to permit the fuel to be provided to the engine in response to the voltage being greater than the voltage threshold.

The invention discloses a power transmission line distributed monitoring device and method supporting unmanned aerial vehicle live-line installation. The power transmission line distributed monitoring device comprises a main control module, a man-machine interaction-free module, a clamping mechanism driving module, a sensing module, a signal conditioning module, a data analysis module, a communication module, a time synchronization module and a power supply module. According to the invention, through the man-machine interaction module and the clamping mechanism driving module, the device can be installed and maintained on the power transmission line by the unmanned aerial vehicle in a live-line manner, and a complete technical link from unmanned aerial vehicle live-line installation to fault identification is constructed; the operation and maintenance convenience is greatly improved, and power supply interruption caused by power failure maintenance is avoided; an open-close type current sensor and a capacitive voltage sensor of the sensing module can accurately acquire electric signals of the line and can accurately identify faults of the power transmission line; the power module integrates a solar panel, an electricity taking CT and a large-capacity battery to form a hybrid energy supply system, and it is guaranteed that energy supply of the device is stable and reliable.

The invention relates to the technical field of motor monitoring and control technologies, and discloses a switched reluctance motor monitoring system and method. According to the switched reluctance motor monitoring system and method, an integrated monitoring system integrating multi-physical-quantity synchronous sensing, high-speed acquisition, edge intelligent diagnosis and active fault tolerance is constructed, so that comprehensive and accurate monitoring is realized; a wide-band and high-precision Rogowski coil, an isolation type voltage sensor and a dual-redundancy position sensor are adopted; by combining distributed temperature and vibration sensing, multi-dimensional synchronous accurate sensing of electrical, mechanical and thermal states is realized, a high-quality data basis is provided for fault diagnosis, the diagnosis is real-time and intelligent, high-speed synchronous acquisition based on the FPGA ensures signal time sequence consistency, wavelet packet decomposition and a lightweight convolutional neural network are fused on the edge side, and the fault diagnosis accuracy is improved. Features can be rapidly extracted locally, faults can be identified, and cloud dependence and diagnosis delay are greatly reduced.

The invention relates to a method for operating a charger (1) for a motor vehicle, in particular an on-board charger for a motor vehicle, the charger (1) having a multi-phase input connection (3) for connection to a multi-phase supply network connection (4) of an in particular stationary supply network, and a voltage converter (5), the voltage converter (5) has at least one intermediate circuit (13) with at least one intermediate circuit capacitor (14, 15). According to the invention, after the input connection (3) is connected to the supply network connection (4), a first intermediate circuit voltage of the intermediate circuit (13) is detected by means of a voltage sensor (V13) of the intermediate circuit (13) before the intermediate circuit (13) is connected to a neutral phase (N) of the input connection (3) by means of an actuatable switching element (S4), and detecting a second intermediate circuit voltage of the intermediate circuit (13) after the intermediate circuit is connected to the zero line of the input connection; furthermore, on the basis of a comparison of the second intermediate circuit voltage with the first intermediate circuit voltage, it is determined whether the supply network connection (4) has a neutral line connected to the neutral line phase (N).

The utility model provides an intelligent fusion terminal combined current sampling and loop inspection system. The intelligent fusion terminal combined current sampling and loop inspection system comprises a microprocessor, and an inspection function module, an electric energy quality detection module, a temperature sensor, a smoke sensor, a level conversion module, a display module, a relay module, a wireless communication module and a zero sequence current transformer which are electrically connected with the microprocessor, the input end of the inspection function module is connected with the combined current transformer, the input end of the electric energy quality detection module is connected with the combined current transformer, the combined voltage sensor and the level conversion module are electrically connected with the arc extinguishing protector, and the relay module is electrically connected with the overvoltage protection module, the overcurrent protection module, the leakage protection module and the field alarm module. According to the utility model, electric power parameters, switch states, fault information and the like in a power distribution loop are automatically monitored, alarm and protection measure starting are carried out on detected abnormal conditions, the monitored electric power parameters can be wirelessly sent to a remote monitoring end, and integrated management of monitoring data is realized.

The invention provides a grounding box non-contact voltage sensor remote diagnosis method, which comprises the steps of obtaining an input and output response curve change trend of a voltage sensor under different voltage levels of a grounding box, determining whether a preliminary abnormal signal exists or not, and obtaining an abnormal preliminary determination result; an electrostatic force gathering parameter is extracted from the metal debris distribution characteristics, a metal debris accumulation path is mapped, the metal debris accumulation path and the input and output response curve change trend of the real-time voltage sensor are subjected to superposition processing, and an electric field abnormity source is determined; and based on an electric field abnormal source, fusing the metal debris accumulation influence degree and the metal debris distribution characteristics to generate a grounding box non-contact voltage sensor remote diagnosis report, sending the remote diagnosis report to a diagnosis system, and obtaining an updated voltage sensor calibration reference.

A three-class AC power supply voltage value and phase sequence detection system comprises an MCU, and an AC220V / 50Hz conditioning circuit, an AC115V / 400Hz conditioning circuit, an AC380V / 50Hz conditioning circuit and a protection alarm which are electrically connected with the MCU, the AC220V / 50Hz conditioning circuit comprises a Hall voltage sensor, the input end of the Hall voltage sensor is connected with a conditioning resistor R in series and then is connected with a power supply, the output end of the Hall voltage sensor is connected with a capacitor C55 in series and then is connected with an input port of the MCU, and the protection alarm is electrically connected with the MCU. The output end of the MCU is further connected in series with a divider resistor R55 and then grounded, and the input port of the MCU is connected in series with a resistor R75 and then connected with + 3.3 V and is connected in series with a resistor R74 and then grounded; the AC115V / 400Hz conditioning circuit comprises an instrument amplifier and a voltage feedback amplifier, the input end of the instrument amplifier is connected with a power supply after being connected with a resistance voltage division circuit in series, and the output end of the instrument amplifier is connected with a positive input end of the voltage feedback amplifier after being sequentially connected with a capacitor C13 and a voltage lifting circuit in series; the output end of the voltage feedback amplifier is connected with the input port of the MCU and the negative input end of the voltage feedback amplifier. According to the scheme, voltage values of AC220V / 50Hz, AC115V / 400Hz and AC380V / 50Hz can be acquired in real time, the phase sequences of AC115V / 400Hz and AC380V / 50Hz can be measured, and timely protection and alarm can be realized.