739results about "Ac/pulses peak value measurements" patented technology

An apparatus and method thereof for measuring an output current from a primary side of a power converter are provided. A peak detector is designed to sample a peak value of a converted voltage of a primary-side switching current. A zero-current detector detects a discharge-time of a secondary-side switching current through an auxiliary winding of a transformer. An oscillator generates a switching signal for switching the power converter. An integrator generates an integrated signal by integrating the converted voltage of the primary-side switching peak current with the discharge-time. The time constant of the integrator is correlated with the switching period of the switching signal. The integrated signal is thus proportional to the output current of the power converter.

The invention provides a current measuring system and method, wherein the current measuring system comprises two or more magnetic field sensors and a signal processing module; the magnetic field sensors are distributed at the outer side of a measured conductor at equal distance, and each magnetic field sensor is used for acquiring the magnetic density of an induction field generated by a current flowing through the measured conductor; the signal processing module is connected with each signal transmission module through signal transmission parts and is used for linearly summarizing the acquired magnetic densities and calculating the value of the current in the measured conductor based on the summarized magnetic density by summarization. The invention lowers the influence of the shape of the conductor on the acquired magnetic density and the influence of an external current source on a measurement result, therefore, the problem of lower repeatability precision for measurement, caused by irregularity and incapability of compensating interference factors in measurement of circuits by utilizing a current measurement way in the prior art, is solved.

A cabinet formed of a plurality of panels, includes a tamper detection system that includes an electrical circuit for detecting forming of a hole in a protected region of at least one panels. The electrical circuit includes at least one conductive trace on one of the panels. The conductive trace spans a protected region, wherein the minimum distance from any point in the protected region to the at least one conductive trace does not exceed some defined maximum. An electrical current source provides a current through the conductive trace. A sensor is in electrical communication with the electrical current source to sense a change in current provided to the trace and generate a tamper signal in response thereto.

A method and system for detecting the peak of respective half-cycles of a sinusoidal waveform. The sinusoidal waveform is rectified and only sample points above a first threshold are analyzed. The peaks of each half-cycle are only accepted if they are above a second, greater threshold. Peaks below the second threshold are not accepted. The peaks themselves are detected by starting a counter at the first sample in the rectified waveform which is above the first threshold value. Once the rectified waveform descends below the first threshold, the counter is stopped and the maximum value of the previous k samples is the peak value, where k is the counter value for the successive samples above the first threshold. The peak value so determined is rejected if it is less than the second threshold value. On the other hand, when the peak value is above the second threshold, it is averaged with the last valid peak value (above the second threshold). Thus, the V/Hz value remains the same until a new, valid peak is determined. A preferred embodiment implements such a digital peak detector in a digital relay system for detecting overexcitation of a power system.

The present disclosure describes a system for measuring current amplitude in a conductor, comprising at least one Rogowski coil, an integration circuit directly connected to the at least one Rogowski coil, a microprocessor circuit in communication with the integration circuit and configured to receive output from the integration circuit and to calculate energy data comprising current amplitude in the conductor. A method for measuring current in a conductor is also presented.

A system for fault prediction in electrical systems. It includes a network of recording nodes that transmit data to multi-channel recorder. The nodes monitor power quality based on a number of system parameters. These data are assembled into data blocks and are analyzed to determine load factors for the system over time. Data blocks are collected over 22 cycle periods and are evaluated against a derived standard deviation factor for the given system. The standard deviation is used to determine alert and alarm levels. The constant monitoring allows the system to alert workers of a potential upcoming fault in one or more system components. In this way repairs can be made before the component fails and the system experiences a fault condition.

The invention discloses a circuit and a method for detecting a voltage peak. Input voltage information is acquired in a coupling manner by a voltage coupling circuit instead of being sampled by directly connecting a power level circuit, on one hand, the number of pins of a chip can be decreased, and on the other hand, loss can be reduced and efficiency can be improved without a sampling resistor or the like. Besides, first voltage outputted to the voltage coupling circuit by a voltage conversion circuit and a holding circuit is used for conversion and holding, and a peak voltage signal representing direct-current input voltage of a switching power supply can be obtained and used by a follow-up circuit. Components such as a large resistor and a large capacitor are omitted, and compared with the prior art, the circuit and the method for detecting the voltage peak have the advantages that cost is greatly reduced, the size is small, and circuit integration is facilitated.

The invention provides a multi-channel data acquisition synchronization system. The multi-channel data acquisition synchronization system comprises a GPS timing module, an ARM base board, an information sampling board and a computer, wherein the GPS timing module sends the serial port data of the GPS absolute time and second pulse signals to the ARM base board; the ARM base board receives the serial port data and the second pulse signals, implements multi-channel splitting, and then sends the data and signals to the information sampling board; the information sampling board resolves, records and acquires the data and sends the data to the computer; and the computer receives, stores and reads the data sent by the information sampling board, draws a waveform curve graph, and analyzes the circuit data according to the waveform curve graph. The circuit data is acquired by adopting the multi-channel data acquisition synchronization system provided by the invention, no signal interference exists between each acquisition channel, each channel has a uniform time reference, and thus the data with higher accuracy can be acquired.

A peak detector circuit receives an oscillating power supply signal. A capacitor is selectably coupled to the signal and charged to a value corresponding to a peak value of the signal. A switch is then opened to isolate the capacitor. When the signal rises to within a selected threshold, relative to the stored value, a comparator produces a command signal to close the switch, again coupling the capacitor to the signal. The peak detector can also include a tracking circuit that controls the capacitor to track the oscillating signal while the switch is closed, a timer circuit that closes the switch and activates the tracking circuit if more than a selected time passes without production of a command signal, a circuit that controls the polarity of a leakage current of the capacitor, a further auxiliary capacitor and a further auxiliary switch with a further control logic.

The invention discloses a non-invasive method and a system for monitoring an electric load alarm. The method comprises the following steps: obtaining a terminal voltage and a total current at the inlet of an electric load power supply at the current moment; performing electric load characteristic extraction on the terminal voltage and the total current to obtain an electric load characteristic atthe current moment; performing electric load decomposition on the terminal voltage and the total current according to the current electric load characteristic; obtaining a type, a current working state and current electric consumption information of each electrical equipment in the electric load; and generating electric consumption abnormal alarm information of the electrical equipment according to the current electric consumption information and a reference electric consumption information. Once any of the current electric consumption information of the electrical equipment is abnormal, the system can timely discover it and give an alarm. Users can timely view and process the abnormal condition according to the type, the current working state and the abnormal electric consumption information of the electrical equipment with abnormal electric consumption in the abnormal electric consumption alarm information of the electrical equipment.

The invention discloses a positive and negative sequence current real-time detection method, which comprises the steps as follows: a three-phase alternating current is adopted through sampling; a positive sequence angle value Theta+(k) of sampling time synchronously rotating with the current is detected and a negative sequence angle value Theta-(k) which is equal to -Theta+(k) and rotates reversely and synchronously with the current is obtained; the instantaneous value of the three-phase alternating current is converted to the components of alpha (k) and beta (k) under an alpha beta coordinate system; the angle value Theta + of the current sampling time, the components of alpha (k) and beta (k) under Theta- and alpha-beta coordinate system, the angle values Theta + (k -1) and of Theta - (k-1) last sampling time and the components of alpha (k-1) and beta (k-1) of last sampling time are used as known quantity to work out the instantaneous values of the current positive sequence components alpha+(k) and beta+(k) and the instantaneous values of the current negative components alpha-(k) and beta-(k) under the alpha-beta coordinate system; and then Clark conversion is implemented to obtain a current three-phase positive sequence component and a current three-phase negative sequence component. The positive and negative sequence current real-time detection method has simple arithmetic and strong timeliness, solves the problems of complex calculation and arithmetic delay caused by the methods like complex number calculations, filter, synchronous rotation vector building and the like, guarantees the timeliness and accuracy for detecting the positive and negative sequence components, has a broad application scope and is easy for engineering realization.

An AC voltage generated by an AC power source 1 is rectified by a full-wave rectifying circuit 2, which generates a rectified voltage. An internal regulator 33 performs waveform shaping of the rectified voltage. A comparator 42 compares the rectified voltage output from the internal regulator 33 with a reference voltage V1 and detects a period in which the rectified voltage exceeds the reference voltage V1. According to an output signal of the comparator 42, a determination signal generation circuit 50 determines the power source voltage supplied form the AC power source 1 and generates a determination signal. Accordingly, there is no need of a capacitor, etc. for detecting the peak value of the rectified voltage, and it is possible to reduce the size and cost of an AC voltage detection circuit.

An electronic signal level detection system and method are provided. The method receives an analog input signal having a variable voltage and compares the input signal voltage to a threshold. A detection signal is generated for input signal voltages exceeding the threshold in a periodic first time frame. In a second periodic time frame (following the first time frame), a count is updated in response to the generated detection signals. The count is used to create a metric representative of the difference between the input signal voltage and the threshold. The count is incremented in response to the generating a detection signal (“1”) in the first time frame, and decremented in response to not generating a detection signal (“0”) in the first time frame.

The invention discloses an alternating current sensor based on a magnetoelectric laminar composite and with a C-type magnetic ring, which belongs to the field of alternating current sensors. The alternating current sensor is a closed cyclic structure composed of the C-type magnetic ring and a measuring module in the gap of the C-type magnetic ring. The C-type magnetic ring and the measuring module are detachably connected through a supporting layer. The measuring module is in a layered structure and comprises the magnetoelectric laminate material in the middle and a permanent magnet layer arranged symmetrically in the thickness direction of the magnetoelectric laminate material. The cross section of the C-type magnetic ring and the permanent magnet layer completely cover the cross section of the magnetoelectric laminate material. The sensor is simple to use, can be loaded and unloaded at any time without changing the topology of a line to be measured, and is a passive device. The output voltage of the sensor has a good linear relationship with the amplitude of current to be measured. The alternating current sensor can realize wideband measurement and has good anti-interference ability.

An envelope detector circuit, suitable for use in RFID tags, includes a voltage doubler circuit and a biasing voltage generating circuit which comprises components matched respectively to rectifying components of the voltage doubler circuit. A rectifying component of this voltage doubler circuit is formed by a transistor controlled by the biasing voltage generating circuit which provides a biasing voltage to a control gate of this transistor, the biasing voltage generating circuit being arranged so as to permit a determined forward biasing current to flow through the transistor and further rectifying elements of the voltage doubler circuit. This embodiment provides fast, highly sensitive detection of envelope waveforms in input signals. Thanks to the matched rectifying components, efficiency variations due to variations in manufacturing process can be eliminated. The envelope detector circuit is further arranged for maintaining a stable detection independent of variations in temperature.

An apparatus and method for analog-to-digital conversion and peak detection includes at least one stage, which includes a first switch, second switch, current source or capacitor, and discriminator. The discriminator changes state in response to a current or charge associated with the input signal exceeding a threshold, thereby indicating whether the current or charge associated with the input signal is greater than the threshold. The input signal includes a peak or a charge, and the converter includes a peak or charge detect mode in which a state of the switch is retained in response to a decrease in the current or charge associated with the input signal. The state of the switch represents at least a portion of a value of the peak or of the charge.

In a communication system, the signal received or transmitted is required to be maintained within a range for proper operation. For example, a radio frequency signal received from an antenna is usually amplified by a low-noise amplifier (LNA) with adjustable gain. The input RF signal is properly amplified by the LNA further processing by subsequently receive path of the receiver. A peak detector may be used to detect the peak amplitude of the amplified input and provides a proper gain for the LNA. The detected peak amplitude may be affected by the noises which may inadvertently cause the gain control to fluctuate randomly. In order to avoid the above issues, some hysteresis has to be built into the peak detection so that the gain control will not be so sensitive to the noise. The present invention discloses a system and method for peak detection with accurate hysteresis. The peak detection uses a high threshold path and a low threshold path to derive the high and low thresholds for gain control with hysteresis. The high threshold path and the low threshold path use pre-amplifiers with different gain factors to amplify low level signals to overcome the non-linearity issue of input-output transfer characteristic of the peak detectors and consequently results in a peak detection system with accurate hysteresis.

The invention pertains to the technical field of complementary metal-oxide semiconductors, which discloses a complementary metal-oxide semiconductor monolithic integrated peak value detection circuit, comprising: a peak value point seeking circuit which is used for generating a rising edge signal at the time of inputting the peak value point of a sine wave signal A; a peak value point discharge circuit which is used for generating a discharge waveform signal E at the site of inputting the peak value point of the sine wave signal; a digital logic, a digital frequency division signal G and a digital waveform signal F are used for controlling the counting of time intervals of an external clock input I, thus generating a digital output signal H of the characteristic time intervals. The circuit of the invention only carries out the sampling of the peak value point, thus simplifying the requirements on a sampling circuit. The peak value detection circuit utilizes the voltage-time conversion (or voltage-duty ratio conversion); the circuit resolution of the invention is controlled by the frequency of a counting clock, thus being much higher than the resolution of the ordinary analog-to-digital converter with the same digital number. The peak value detection circuit can reduce the volume power consumption and meet the needs of the integration of a sensor and the circuits.

The invention discloses a method for determining a reaction potential of an additive in a lithium-ion cell electrolyte. The method comprises the steps of respectively taking a cathode half cell or an anode half cell as a test unit when the reaction potential of the additive in the lithium-ion cell electrolyte on a cathode or an anode of a lithium-ion cell needs to be measured; carrying out a charge-discharge test on the test unit and simultaneously detecting the cell capacity and the cell voltage of the test unit; carrying out differential treatment on the cell capacity Q and the cell voltage V, which are obtained through detection, of the test unit, calculating a differential value of the cell capacity Q on the cell voltage V, taking the differential value as a y coordinate, taking the cell voltage, which is obtained through detection, of the test unit as an x coordinate, and obtaining a test curve; obtaining a voltage value of each peak in the test curve according to the test curve. According to the method for determining the reaction potential of the additive in the lithium-ion cell electrolyte, disclosed by the invention, the reaction potential of the additive in a cell electrolyte can be accurately measured.

The invention discloses a method for online separately detecting resistive leakage current of a non-voltage reference source, thereby realizing that the resistive current value can be effectively acquired, validity and accuracy of detection of the lightning arrester state can be improved, and the reliability of system operation can be improved. The invention is realized through the following technical proposal that the method for online separately detecting resistive leakage current of the non-voltage reference source comprises the following steps: firstly, sampling a leakage full current periodic signal of the lightning arrester with fixed period; secondly, determining a peak value of capacity current according to the leakage full current periodic signal sampled on the step S1; thirdly, acquiring leakage resistive current through calculating according to the leakage full current periodic signal sampled on the step S1 and the peak value of the capacity current determined on the step S2 of determining the current peak value; and finally, determining a periodical leakage resistive current waveform according to the leakage resistive current acquired by calculation on the step S3 of determining the resistive current.

A low-loss current sensor for use with a circuit containing a capacitor to sense a current flowing into a node in the circuit is provided. The current sensor includes a differentiator circuit having an input connected to the circuit capacitor and adapted to generate an output which is proportional to the current flowing through the circuit capacitor. The novel use of a capacitive current divider allows the sensor to sense current with virtually no power dissipation.