247 results about "Phase displacement" patented technology

The invention relates to the technical field of fault detection, in particular to an electrical equipment fault diagnosis method and system, and the method comprises the following steps: constructing a ratio group of a trigger incremental sequence quantity and a frequency spectrum cluster set based on a partial discharge pulse interval, deducing impedance frequency boundary migration, analyzing a conductor heating and cooling rate difference, and forming thermal response lag information. According to the method, frequency spectrum energy evolution characteristics are extracted through partial discharge pulse interval dynamic behaviors, a frequency migration path is constructed to reflect an impedance boundary fluctuation process, hysteresis effect characteristics are extracted in combination with thermal inertia response differences in a temperature rise stage, and the impedance boundary fluctuation is determined. And analyzing a voltage and current phase fluctuation rule and deducing a change trend of a combined feature, establishing a layer-by-layer progressive judgment logic between multi-stage dynamic coupling features, realizing evolutionary process tracking from local disturbance to a global abnormal state, and improving a fine-grained identification level of an abnormal mechanism in an electrical equipment operation behavior.

The invention belongs to the technical field of magnetic variable measurement, and particularly relates to a power driving compensation method and system for magnetostrictive load characteristic monitoring, and the method comprises the steps: obtaining a reference zero point of magnetic performance evolution in a cold state environment of an electromagnetic system according to the center frequency of the electromagnetic system; calculating a current main frequency impedance module value and a phase difference through an electrical parameter characterization method, and obtaining a thermal drift index reflecting a hysteresis loop distortion degree in combination with a reference zero point; obtaining correction factors of all orders based on the thermal drift index and the average output power at the current moment, and dynamically updating a coefficient vector of the inverse model; and constructing a pre-distortion driving voltage signal capable of counteracting nonlinear interference by using the new coefficient and the ideal guided wave voltage sequence, and inputting the pre-distortion driving voltage signal to a power amplifier to drive the magnetostrictive transducer. According to the invention, the problem of predistortion failure under a variable-temperature working condition in the prior art is solved, and the signal-to-noise ratio of high-power long-distance guided wave detection is remarkably improved.

The invention discloses a pre-synchronization control method for a network-building converter based on a virtual synchronous generator, and the method comprises the steps: collecting the three-phase voltage of the output end of the virtual synchronous generator VSG and the three-phase voltage of a power grid side, converting the three-phase voltage into a voltage component in a two-phase static coordinate system through Clark conversion, and extracting a positive-sequence component; calculating a phase difference compensation coefficient based on the positive sequence component; based on the phase difference compensation coefficient, adaptively setting a PI parameter; and calculating and adjusting the amplitude of the internal potential to finish pre-synchronization. In the working process, through self-adaptive PI parameter setting and amplitude accurate judgment, the pre-synchronization time is shortened, the grid-connected impact current is reduced, and the grid-connected success rate of the micro-grid in a weak grid scene is improved.

The invention discloses a withstand voltage test method and device for transformer production and a medium, and belongs to the technical field of transformer tests.The method specifically comprises the steps that firstly, a frequency conversion test power source is connected to the input end of a to-be-tested transformer and connected with a high-precision non-inductive shunt in series, and an environment monitoring unit is started to lock temperature and humidity in real time; the control power supply outputs a standard sine test voltage with a preset frequency; then, a high-frequency broadband acquisition card is used for synchronously obtaining instantaneous waveform data of voltage and total leakage current of the transformer, and analog signals are converted into discrete digital signals; performing second-order difference on the total leakage current signal to position a high-frequency abrupt change point, and reconstructing a smooth waveform through Lagrange interpolation; a current phase difference is calculated by taking a voltage zero crossing point as a phase reference, a complex plane coordinate system is constructed, and resistive and capacitive current components are calculated through waveform amplitude projection; and finally, according to the temperature and the humidity, a correction coefficient is called to normalize the resistive current, and a quality inspection result is output by comparing an insulation safety threshold.

The invention discloses a dry-type air-core reactor loss measurement method, device and system, and relates to the technical field of reactor loss factor measurement. The method comprises the following steps: in response to an obtained electrical parameter signal of the dry-type air-core reactor, performing Fourier transform on a voltage signal in the electrical parameter signal, and determining the fundamental wave purity of the dry-type air-core reactor; the electrical parameter signal comprises a voltage signal and a current signal, the voltage signal comprises a voltage amplitude and a voltage phase, and the current signal comprises a current amplitude and a current phase; based on the current amplitude and the phase difference between the voltage phase and the current phase, determining a harmonic judgment value of the dry-type air-core reactor; determining a defect correction coefficient of the dry-type air-core reactor based on the phase difference between the voltage phase and the current phase; and determining the loss factor of the dry-type air-core reactor based on the fundamental wave purity, the harmonic judgment value and the defect correction coefficient of the dry-type air-core reactor. According to the invention, the identification precision of the defects of the dry-type air-core reactor can be improved.

The invention relates to the technical field of electric switches, in particular to an electric disconnecting switch interlocked with a pole-mounted circuit breaker and a control method thereof, and the method comprises the steps: obtaining standard coil current data, actual coil current data, main loop three-phase current data, power side voltage data and load side voltage data, and carrying out the preprocessing; determining time division points by using the wave crest and wave trough distribution characteristics so as to divide stage intervals; the health coefficient of the pole-mounted circuit breaker is obtained through stage interval similarity analysis; calculating an electrical isolation coefficient by combining the main loop current level difference and the bilateral voltage amplitude phase difference; and performing hierarchical interlocking control on the electric isolation switch based on the health coefficient and the electrical isolation coefficient. According to the invention, a two-dimensional evaluation system of mechanism health pre-judgment and electrical isolation hard criteria is constructed through multi-source data fusion, and the safety and reliability of distribution network operation are improved through a hierarchical interlocking control strategy.

The invention discloses a network construction type converter pre-synchronization control method based on Taylor compensation, and the method comprises the steps: collecting the three-phase voltage of an output end of a virtual synchronous generator (VSG) and the three-phase voltage of a power grid side, carrying out the Clark transformation, and extracting a positive sequence voltage component; on the basis of the positive sequence voltage component, calculating a phase difference sine value of the VSG output voltage and the power grid voltage; based on the phase difference sine value, compensating the phase difference sine value through Taylor expansion to obtain a compensated real-time phase difference; and fusing the compensated real-time phase difference into a VSG phase-locked loop-free pre-synchronization control strategy, and driving a PI regulator to dynamically correct the output frequency and phase of the VSG. A phase-locked loop is completely abandoned, and the frequency oscillation risk is eliminated; expanding a phase difference calculation range through third-order Taylor compensation; voltage vector analysis and a dynamic compensation function are fused, phase synchronization is achieved, and grid-connected impact current is reduced.

The invention relates to the technical field of electrical fault detection, in particular to an online fault judgment and automatic detection method for a marine cable, which comprises the following steps of: acquiring ground leakage current and load current in operation, extracting an active component of the leakage current and analyzing the nonlinear correlation between the active component and the load current to realize online early warning of insulation degradation; when the ship is in a working condition of allowing short-time power failure of partial non-critical loops, positioning a fault branch based on a normalization result of the ground capacitance variation before and after the power failure of each branch and the cable length; after power supply is recovered, the fault type is judged by combining the leakage current fundamental wave and phase voltage phase difference and the harmonic distortion rate; during power-off maintenance, high-frequency carrier waves are injected, the position of a fault point is determined according to current attenuation abnormity, correction is carried out by combining temperature and vibration factors, and the detection accuracy and the positioning precision are improved.

The invention discloses a grid drive short-circuit protection method based on dV / dt detection, which relates to the technical field of power electronics, and comprises the following steps: constructing a unified time frequency reference baseline, executing all-phase mapping on each power device of a parallel system, reconstructing a conduction sequence, and calculating a phase difference between a voltage rising edge and sampling trigger. Generating a time frequency dislocation matrix, and determining a phase dislocation risk window; and executing causal playback in the phase dislocation risk window, extracting transient waveform characteristics of a voltage rising edge, eliminating parasitic pseudo peaks, obtaining an effective response trajectory, generating a sampling phase check anchor point based on the trajectory, and constructing a phase reference baseline. According to the method, a unified time-frequency baseline and a dynamic sampling mechanism are constructed to realize phase synchronization of sampling and conduction, the sampling rhythm and the turn-off threshold are optimized in combination with feed-forward vibration suppression and residual adjustment, the short circuit identification speed and precision are improved, and the method has self-healing and self-correcting capabilities and is suitable for high-frequency and high-power density scenes.

According to the high-low voltage lead structure of the single-machine 48-pulse hydrogen production rectifier transformer, a left device body, a right device body and a self-coupling modulation device body are arranged in an oil tank of the single-machine 48-pulse hydrogen production rectifier transformer, the self-coupling modulation device body is connected with the left device body and the right device body at the phase angle difference of 7.5 degrees, and the self-coupling modulation device body is powered by a grid-side three-phase power source. Power sources of the left transformer body and the right transformer body are output through the self-coupling modulation transformer body, a phase shift phase with the phase angle difference of 7.5 degrees is arranged between the left transformer body and the right transformer body, and four rectifiers with 12 pulses and 15-degree phase difference can be dragged by the valve side of a single 48-pulse rectifier transformer, so that the one-to-four function can be effectively realized, and the power consumption is reduced. Meanwhile, the size and the weight of the system are effectively reduced, the overall manufacturing cost is greatly reduced, and rapid industrialization of green hydrogen is facilitated.

The precision capacitance micrometer system comprises a modulation signal source, a sensitive probe, a differential transformer bridge circuit, a signal amplification link, a multiplier and a low-pass filter circuit which are electrically connected in sequence, a double-limit comparator is arranged between the signal amplification link and the multiplier; the input end of the double-limit comparator is connected with the output end of the signal amplification link, the output end of the double-limit comparator is connected to one input end of the multiplier, and the double-limit comparator is used for shaping the amplified modulation signal and taking the shaped signal as the demodulation input signal. The invention also provides a precise capacitance micrometer method. The precise capacitance micrometer system provided by the embodiment of the invention ensures that the system output is insensitive to phase difference fluctuation within a certain demodulation phase difference range, and finally realizes high-precision measurement of micro displacement. All the modules complete full-link conversion from physical quantity to measurable voltage signals through step-by-step signal transmission and function complementation.

The application discloses a kind of calibration method and device for rotary variation soft decoding, calibration method includes: according to N times oversampling frequency respectively sampling rotary variation feedback sine and cosine feedback signal envelope surface and obtaining positive, cosine oversampling signal;Positive, cosine oversampling signal is handled to obtain the zero position offset of rotary variation positive, cosine envelope signal;Positive, cosine oversampling signal is handled to obtain the amplitude of rotary variation positive, cosine envelope surface;Positive, cosine oversampling signal is handled to obtain the phase deviation of rotary variation positive, cosine envelope surface;Through the amplitude, zero position offset, phase deviation obtained by calculation, the envelope surface of rotary variation positive, cosine is compensated, and the signal after compensation is sent into phase-locked loop to obtain the angle and rotational speed information of rotary variation.The application obtains accurate amplitude, zero position offset, phase difference in turn, and then carries out error compensation, finally obtains corrected positive, cosine signal, effectively guarantees the efficiency of motor.

The invention relates to the technical field of transmission, and discloses a transmission system, by adopting a first metal conductor array and a second metal conductor array, metal conductors can reversely influence an original magnetic field emitted by a coil assembly, so that the coil assembly can detect the change of the magnetic field, and a first voltage signal and a second voltage signal are obtained; the length of the first metal conductor along the transmission direction is different from the length of the second metal conductor along the transmission direction, so that the first periodic position signal and the second periodic position signal have a phase difference. Therefore, the absolute position of the rotor can be determined according to the first periodic position signal and the second periodic position signal with the phase difference.

The invention relates to the technical field of power system fault detection, in particular to a factory power distribution system fault interval section determining method and system and terminal device.The factory power distribution system fault interval section determining method comprises the steps that when a power failure fault of a power distribution system is monitored, voltage and current data within a preset duration before the fault is obtained; comparing the phase current amplitude with a rated current threshold value, judging that the phase current amplitude is an external fault if the phase current amplitude does not exceed the limit, calculating a zero-sequence current if the phase current amplitude exceeds the limit, and comparing the zero-sequence current with a zero-sequence threshold value to distinguish a ground fault or an inter-phase fault; adaptively calling a phase difference analysis process according to an identification result, calculating a phase difference between a zero-sequence current and a zero-sequence voltage during a grounding fault, calculating a phase difference between a fault phase voltage and a fault phase current during an inter-phase fault, and judging whether a fault interval is internal or external according to a phase difference interval; and a structured message is automatically generated by integrating fault types, interval judgment and triggering criterion paths, so that quick and accurate fault positioning and handling are realized.

The invention discloses a rotor position detection method for multiplexing a synchronous motor body as a rotary transformer, and the method comprises the following core steps: a, independent detection windings (2) are embedded in grooves of a stator (3), the number of detection coils contained in each phase of independent detection winding (2) is equal to 1 / 2n of the number of rotor salient poles (4), and n is a natural number smaller than 10; b, detection coil parameters of all the independent detection windings (2) are completely consistent, the electrical phase difference between the independent detection windings (2) of each phase is equal to 360-degree electrical angle divided by the phase number of the independent detection windings, and the independent detection windings (2) are uniformly distributed on the inner circumference of a stator slot; c, the independent detection windings (2) of all phases are sequentially connected in series end to end and then connected into a carrier signal generated by a carrier generator, and the real-time angle position of the rotor salient pole (4) is calculated through a precise full-wave rectifier, a potential translation circuit and a position conversion module. A solid rotor position sensor is abandoned, a synchronous motor body is reused as a core component of a rotary transformer, and sensorless rotor position detection is achieved; the device adapts to special working conditions such as high temperature, strong electromagnetic interference and full sealing; according to the invention, excitation current interference is eliminated, the detection precision is improved, position closed-loop control in a zero-speed-full-speed range is realized, the response speed is high, the control precision is high, the production cost is low, and the synchronous motor is suitable for various synchronous motors with rotor magnetic resistance anisotropy and circumferential uniform distribution, such as a new energy automobile dragging motor, a linear motor and a household appliance totally-enclosed compressor.

The present application relates to the technical field of mutual inductor design, and particularly relates to a method for obtaining core magnetic performance at low cost to evaluate the accuracy level of a mutual inductor, which comprises using a mutual inductor calibrator to test a current mutual inductor; during the testing, by changing the data of primary current, the ratio of transformation difference and phase difference of the mutual inductor under different current points are obtained, and then the B-H curve and the delta-H curve of the core of the mutual inductor are derived by using the reverse deduction method based on the obtained ratio of transformation difference and phase difference data. The present application innovatively designs a method for obtaining core magnetic performance curve at low cost to evaluate the accuracy level of a mutual inductor without using a special core curve testing instrument, thereby providing a basis for the design of the mutual inductor.

The invention relates to the technical field of high-frequency transformers, in particular to a design method and system for reducing distributed capacitance of a high-frequency drive transformer, and the method comprises the following steps: collecting instantaneous voltage and current of a winding, fitting an energy density curve, analyzing the coupling strength of a capacitance region, extracting voltage response, smoothly correcting deviation, and positioning capacitance space distribution; detecting a current phase difference and an energy path, judging a capacitance concentration ratio and adjusting a layout coordinate, calculating a phase deviation and energy ratio comparison, optimizing a capacity and spacing ratio, and correcting an error to generate an optimization result. According to the invention, accurate optimization is realized by acquiring voltage and current and fitting an energy density curve, analyzing coupling strength and capacitance distribution, iteratively correcting deviation, adjusting the proportion of capacitance to spacing, balancing an electromagnetic coupling state, improving energy transfer efficiency, reducing parasitic effect, and enhancing system stability and anti-interference capability; and the energy conversion quality and the structural reliability are improved.

An apparatus comprising a phase locked loop circuit including: an input configured to receive an oscillating reference signal having a reference period; a current-controlled-oscillator (CCO) configured to generate an oscillating output signal based on an input signal; an error detector configured to generate one or more error signals based on a phase difference between the reference signal and one or more feedback signals wherein the feedback signals are based on the oscillating output signal; and a charge pump circuit configured to receive at least a first of the error signals, determine a voltage indicative of a duration of the first error signal during a first part of the reference period, and provide a control current to the CCO for at least a remaining part of the reference period, wherein the control current comprises at least part of the input signal to the CCO and is based on the determined voltage.

This invention discloses a control method, device, and medium for a three-phase surge arrester. The method includes: performing a difference calculation on the phase of the three-phase fundamental component and the phase of the three-phase current to obtain a phase difference set; calculating the capacitive current of the three-phase surge arrester based on the amplitude of the three-phase fundamental current and the phase difference set; calculating the three-phase resistive fundamental current using the lead-lag relationship in the phase difference set based on the amplitude of the three-phase fundamental current, the phase difference set, and the capacitive current; and correcting the actual three-phase resistive fundamental current of the three-phase surge arrester using the three-phase resistive fundamental current. This invention proposes a control method, device, and medium for a three-phase surge arrester. By calculating the three-phase resistive fundamental current using acquired data information and then using this value to correct the actual three-phase resistive fundamental current of the three-phase surge arrester, it can solve the problem of not being able to easily and effectively eliminate interference caused by inter-phase coupling capacitance during live testing of the surge arrester.

The present application relates to a kind of double anti-star transformer rectification harmonic suppression control method.By establishing the rectification bridge arm phase characteristic parameter table in control platform, the theoretical conduction phase of bridge arm, winding attribution and waveform synchronization characteristic are recorded;In the operation process of rectification control unit, the output current of transformer and bridge arm conduction state are collected, and rectification operation state data set is generated;The conduction phase offset of bridge arm is calculated, the corresponding harmonic component is analyzed, and the mapping relationship between bridge arm state and harmonic distribution is obtained.According to the mapping result, it is judged whether the current bridge arm configuration meets the phase coverage requirement of target rectification pulse number, if not, select the standby bridge arm group with preset phase difference and generate switching instruction.Rectification control unit responds to instruction to lock current bridge arm conduction path and release target bridge arm group, realize bridge arm resource dynamic reconstruction and rectification performance optimization.The present application can effectively suppress harmonic, improve the topology adaptability and output quality of rectification system.

The invention provides a power electronic transformer carrier synchronization control method and system based on a DBA topological structure, and the method comprises the steps: carrying out the time domain feature extraction processing through obtaining a switching signal waveform, generating an initial synchronization reference sequence, obtaining the magnetic flux change rate data of a high-frequency transformer, and carrying out the time domain feature extraction processing; the method comprises the following steps: carrying out characteristic correlation on an initial synchronous reference sequence to obtain a carrier period correlation degree and a phase difference distribution curve, generating a matching parameter of a carrier period and a phase based on the two curves, obtaining parallel circulating current amplitude data of a target loop, carrying out segmented threshold determination, and obtaining a circulating current amplitude overrun interval and an amplitude change gradient; and generating a frequency adjustment parameter based on the two, fusing the frequency adjustment parameter and the system operation state data to obtain a fused feature vector, performing phase alignment information reconstruction, generating reconstructed phase alignment information, and generating a multi-stage synchronous control instruction based on the reconstructed phase alignment information to control a switch time sequence. The carrier synchronization precision and the system operation stability of the power electronic transformer are improved.

The invention relates to an on-line ice preventing / melting method for a railway overhead line system powered by a star-delta transformer. The method comprises the following steps that the star-delta transformer is transformed; calculating corresponding required phase differences under different ice melting current values; the phase difference is used for judging the required transformer ice melting gear K at the moment; selecting a proper number of windings according to the K value in the third step; adjusting the number of turns of the corresponding winding of the transformer according to the winding turn value in the fourth step; and switching on the isolation switch of the partition post to melt ice. The method has the beneficial effects that the phase shifting function of the adjusted transformer is utilized, so that the traction power supply system forms circulating current to melt ice, normal operation of a train in extremely cold weather such as freezing rain is ensured, and large-area train shutdown caused by icing of a contact network is avoided.

The invention discloses a three-phase cable live-line state identification device and method based on an annular magnetic field sensing array, and belongs to the technical field of power system safety detection. Existing non-contact electricity testing methods cause misjudgment due to the fact that target cable body current and adjacent loop coupling current are difficult to distinguish. The cable is sleeved with an openable annular support, three magnetic field sensors are fixed to the inner side of the openable annular support circumferentially, and each magnetic field sensor is aligned to the position over a corresponding phase conductor in the three-phase cable in space so as to independently sense the power frequency magnetic field of each phase; the method comprises the following steps: processing three paths of synchronously acquired signals, extracting an instantaneous phase of each signal, and calculating a phase difference between every two signals; and finally, according to a comparison result of the three phase differences and a preset criterion, judging that the cable is in a normal electrified state, an external coupling interference state or a non-electrified state without obvious external magnetic field interference and the like. According to the technical scheme, non-contact, rapid and reliable live-line state identification can be effectively carried out on the three-phase cable.

The invention discloses a phase-shifting transformer and a voltage-phase coordinated regulation and control method and system thereof.Decoupling of a three-phase magnetic circuit is achieved through the structural design of the phase-shifting transformer, control of the voltage-phase coordinated regulation and control system is matched, and the voltage-phase coordinated regulation and control of the phase-shifting transformer is achieved by moving a secondary winding of a B-phase iron core column and a C-phase iron core column on the corresponding iron core column. Flux linkage coupling of the winding and the primary winding is continuously and linearly changed, and continuous and accurate adjustment of the phase difference is achieved; meanwhile, a plurality of voltage regulating taps with tap switches are arranged on the secondary winding of the B-phase iron core column and the high-voltage sub-winding of the C, so that the effective turn ratio of the high-voltage sub-winding is independently changed, and the graded accurate regulation of the amplitude of the output voltage is realized; according to the method, a hierarchical control strategy is utilized, phase adjustment is rapidly completed preferentially, and voltage adjustment is executed after a system judges that a magnetic circuit is stable, so that the stability of each regulation action and the equipment safety are ensured, and the dynamic response speed and the control reliability of the system are greatly improved.

The application relates to the field of power electronics, and discloses a control method for wide-voltage operation of a CLLC resonant converter. In the CLLC resonant converter, the same-name end of the primary side is connected to the emitter of a switching tube Q1 and the collector of a switching tube Q2, and the different-name end is connected to the emitter of a switching tube Q3 and the collector of a switching tube Q4; the same-name end of the secondary side is connected to the emitter of a switching tube S1 and the collector of a switching tube S2, and the different-name end is connected to the emitter of a switching tube S3 and the collector of a switching tube S4; the method comprises the following steps of O-mode under the PO mode: when being in the positive half cycle, if the output voltage of the secondary side is greater than zero, the switching tube S2 is turned on in advance by a phase difference alpha relative to the end phase of the O-mode; and when being in the negative half cycle, if the output voltage of the secondary side is less than zero, the switching tube S1 is turned on in advance by the phase difference alpha. The method is related to a circuit structure which is simple, can effectively widen the voltage gain range, realizes higher voltage gain at lower loss and cost, is more suitable for wide-range voltage operation, and has higher stability.

This application relates to the field of electronic power technology, and proposes a control method, control device, electronic device, and readable storage medium for an inverter. The inverter control method includes: acquiring a first voltage from the power grid; determining a first angular frequency and a first phase corresponding to the power grid based on the first voltage; acquiring a second angular frequency and a second phase of the inverter; determining a first frequency difference based on the first and second angular frequencies; determining a first phase difference based on the first and second phases; determining a target voltage for the inverter based on the first frequency difference and the first phase difference; and controlling the duty cycle of the inverter's switching components based on the target voltage. The inverter control method provided in this application can ensure synchronization between the operating parameters of the inverter and the power grid when the inverter is connected to the power grid, avoiding large impacts on the inverter and ensuring stable operation of the inverter.

The embodiment of the invention provides a dual-phase-discriminator phase-locked loop control method and a grid-connected inverter, and the method comprises the steps: obtaining the voltage of a power grid, and determining the sampling frequency of the voltage of the power grid; determining at least one sampling period according to the sampling frequency; determining phase sine values and phase cosine values of a plurality of sampling periods according to the power grid voltage; determining a first phase difference signal through a first phase discriminator; determining a matching frequency and an output phase value corresponding to the matching frequency according to the first phase difference signal; determining a second phase difference signal through a second phase discriminator; determining a total phase adjustment amount according to the first phase difference signal and the second phase difference signal; and determining a phase-locked phase value according to the total phase adjustment quantity so as to update the output phase value. According to the scheme of the invention, high-stability technical guarantee is provided for realizing grid connection of high-performance energy storage equipment.

The invention discloses an ultrasonic motor driving control strategy based on voltage amplitude-frequency hardware decoupling. Phase voltage, phase current and rotation angle signals of a motor are sampled through a sensor and an encoder, a voltage and current phase difference is obtained by adopting a zero crossing point detection method, resonant frequency is obtained by combining a PID frequency regulator, and independent frequency control is realized by matching with a fixed duty ratio; the rotating speed is obtained through differential operation, reference voltage is obtained through a PI regulator, and independent amplitude control is achieved by combining a voltage amplitude obtained through a rectification average value method with a PID voltage regulator and matching with a fixed frequency. The two-stage circuit topology is adopted to independently regulate and control the voltage amplitude and the voltage frequency, the problems that voltage amplitude regulation is nonlinear and voltage frequency regulation is coupled in a traditional ultrasonic motor driving scheme are solved, the voltage amplitude is independently regulated at the front stage, the voltage frequency is independently regulated at the rear stage, hardware decoupling of the voltage amplitude and the voltage frequency is achieved, and the system reliability is improved. The harmonic content of the output voltage of the driving circuit is lower, and the voltage control is more linear.

A measurement correction method and signal conditioning apparatus for a linear variable differential transformer sensor. The correction method comprises the following steps: acquiring a compensation fitting coefficient (101); obtaining a root mean square value signal of an excitation voltage signal, a phase difference signal and a root mean square value signal of an induced voltage signal of when a linear variable differential transformer sensor is used to measure the displacement of an object to be measured (102); and on the basis of the numerical value of the root mean square value signal of the excitation voltage signal, the numerical value of the phase difference signal and the numerical value of the root mean square value signal of the induced voltage signal of said object and in view of the compensation fitting coefficient, performing temperature drift compensation, so as to obtain a corrected displacement measurement value (103). The above solution can compensate for the displacement data drift caused by the impact of temperature on a linear variable differential transformer sensor, thereby reducing the impact of temperature drift on the output of the linear variable differential transformer sensor.

The embodiment of the invention provides a zero-sequence CT polarity verification method and device, equipment, a medium and a product. The method comprises the following steps: if protection tripping occurs in a feeder line of the power distribution network and a fault of the feeder line disappears after the protection tripping, acquiring a bus zero-sequence voltage of the power distribution network and a zero-sequence current of the feeder line in a period, and then respectively calculating the amplitude of the bus zero-sequence voltage and the amplitude of the zero-sequence current through a preset fitting function. And determining the phase difference between the zero-sequence voltage and the zero-sequence current of the bus according to the amplitude of the zero-sequence voltage and the amplitude of the zero-sequence current of the bus. And finally, according to the phase difference and a preset phase difference range, determining a polarity verification result of the zero-sequence CT of the feeder line. The method is used for achieving the technical effect of improving the zero-sequence CT polarity verification accuracy.