184results about How to "Waveform distortion is small" patented technology

The invention relates to a three-phase sinusoidal voltage control driving system for a permanent magnet synchronous motor, in particular to a Hall position sensor-based position estimation and compensation method for the permanent magnet synchronous motor. The method comprises the following steps of: driving the permanent magnet synchronous motor to rotate at constant speed in a VVVF manner by a controller, and detecting a position signal transmitted back by a Hall sensor to obtain the distribution proportion of six position intervals under an electrical angle of 360 degrees; obtaining a position interval with a calculation number i according to the distribution proportion, and estimating a correction coefficient V[i] of an angle change value; and correcting T in an angle estimation formula 60*t / T to finally obtain a corrected angle estimation formula 60*t / (V[i]*T), wherein i is the number of the position interval, and V[i]*T in the corrected angle estimation formula is time actually required by the rotation of the motor by the position interval with the number i. A position angle change value calculated according to the formula in the interval always changes linearly within 0 to 60 degrees regardless of an electrical angle actually corresponding to the position interval.

The invention discloses a bidirectional direct-current converter feedback linearized back-stepping sliding-mode control mode. The bidirectional direct-current converter feedback linearized back-stepping sliding-mode control method comprises steps of using a filtering capacitance voltage and inductive current as control variables to establish a mathematic model of a bidirectional direct-current converter, performing feedback linearization on an original state variable to form a new linearized state equation, tracking an error with a new state variable as an input of a controller, combining a back-stepping method with a sliding-mode variable structure and designing a feedback control rule of a converter system, wherein the feedback control rule of the inverter system is performed on pulse width modulation and controls the bidirectional direct-current converter. The bidirectional direct-current converter feedback linearized back-stepping sliding-mode control mode combines the feedback linearization with the back-stepping sliding mode control to apply to the bidirectional direct-current converter, solves a non-minimum phase characteristic and a variable structure characteristic of the converter, greatly reduces fluctuation of bus voltage, expands a stable area of a system and has a good engineering application prospect.

The invention relates to a control method for a photovoltaic grid-connected inverter on the basis of back-stepping sliding-mode control. The control method is technically characterized in that direct current voltage Udc of a photovoltaic side bus is collected, a mathematical model of a photovoltaic grid-connected single-phase voltage full-bridge inverter is set up, a tracking error of a control variable uac is set, a back-stepping sliding-mode control model of the photovoltaic grid-connected single-phase voltage full-bridge inverter is set up, and the single-phase photovoltaic grid-connected inverter is controlled according to the mathematical model and the back-stepping sliding-mode control model of the photovoltaic grid-connected single-phase voltage full-bridge inverter. The control method is reasonable in design, a back-stepping method and a sliding-mode control method are combined, the stable state and the dynamic property are good, and the control method is suitable for linear and non-linear loads and adapts to engineering application reality, provides a new thought for the inverter control system design and has the good engineering application prospect.

To provide a semiconductor device which operates stably with few malfunctions due to noise, with low power consumption, and little variation in characteristics; a display device including the semiconductor device; and an electronic device including the display device. An output terminal is connected to a power supply line, thereby reducing variation in electric potential of the output terminal. In addition, a gate electrode potential which turns ON a transistor is maintained due to the capacitance of the transistor. Further, change in characteristics of the transistor is reduced by a signal line for reverse bias.

The embodiment of the invention provides a design method for a cascade filter, which comprises the following steps of: determining the interpolation times N of the filter; calculating the filter coefficient of a programmable finite impulse response (PFIR) filter, and obtaining a design scheme of a cascade combined filter of PFIR and cascaded integrator comb (CIC) filters; and when the interpolation times of the cascade combined filter of the PFIR and CIC filters does not reach the predetermined times, designing a half band (HB) filter, so that the filter performance of the cascade combined filter of the PFIR and CIC filters and the HB filter meets the interpolation times requirement of a system, and the design of the PFIR filter is realized by adopting a multistage design scheme. According to the embodiment provided by the invention, by adopting the design device for the multistage filter, the order of the designed filter is in a realizable range of the FPGA, and the indexes such as interpolation times of signals, error vector magnitude (EVM), adjacent channel power ratio (ACPR) and the like can meet the protocol requirement. Moreover, according to the technical scheme provided bythe invention, the resource consumption of the filter is also lower than that of the design method for the traditional filter, and the use of FPGA hardware resources can be effectively reduced.

The invention discloses a position estimation compensation method for a permanent magnet synchronous motor based on a Hall position sensor, and the method comprises the following steps: carrying out the sector division of each electrical angle of an electrical angle period of a rotor in the permanent magnet synchronous motor, and obtaining an actual initial angle theta<rb> of a corresponding sector when a signal of the Hall position sensor jumps from an edge; estimating an angle increment theta in an interval according to the rotating speed of the permanent magnet synchronous motor; obtaining an estimated angle theta<e> according to a formula: theta<e>= theta<rb>+ theta; further calculating the actual installation angle theta<r> of the Hall position sensor; finally solving the difference between the estimated angle theta<e> and the actual installation angle theta<r> to obtain an error E<theta>, and calculating a compensation value theta<c> through a PI regulator, wherein after the process is circularly executed in this way for multiple periods, E<theta> approaches 0, and when motor control is conducted, three-phase sine voltage waveform distortion is greatly reduced, and torque pulsation and noise are reduced.

The invention provides an electrocardiosignal preprocessing method based on morphological multiresolution decomposition, which comprises the following steps that (1) a linear structural element is applied to drifting of a correction baseline of a morphological filter; (2) a lifting method is applied to constructing of morphological multiresolution to decompose an electrocardiosignal to a second layer and a third layer; and (3) a component with less QRS (Quantum Resonance Spectrometer) complex wave distortion in signal components of the second layer and the third layer is selected as a preprocessed electrocardiosignal. According to the electrocardiosignal preprocessing method, the linear structural element is applied to drifting of the correction baseline, so that waveform distortion is reduced to a greater degree. A morphological multiresolution decomposition method is applied to filtering of high-frequency noise such as electromyography disturbance, the performance is superior to that of the preprocessing method of wavelet transform and morphological filtering, and the method is simple and easy to realize. The lifting method is adopted to construct multilayer morphological decomposition, because prediction and update operators which are suitable for the electrocardiosignal are selected, the denoising performance is further optimized, and the distortion of characteristic waves of the electrocardiosignal is reduced.

A magnetoresistive element includes a meandering X-axis array that is constituted by X-axis segments alternately connected, and a meandering Y-axis array that is constituted by Y-axis segments alternately connected. When rotated 90°, the Y-axis array has the same layout as the X-axis array. Such a structure cancels the electrical resistance change due to the AMR effect, thus reducing the waveform distortion of output voltage.

A transmission device includes a pulse modulated signal generator that generates a pulse-modulated signal by changing the width of a pulse or the density of a pulse according to the magnitude of the amplitude component of an input signal while discretely changing the pulse height according to the magnitude of the amplitude, a modulated-signal generator that generates a modulated signal by integrating the pulse-modulated signal and the phase component of the input signal, a power amplifier that includes at least as many amplifiers as the number of the discrete amplitude levels of the modulated signal, changes the number of amplifies that amplify the modulated signal on the basis of the value of the amplitude level of the modulated signal, combines outputs of the amplifiers, and outputs a combined output, and an output filter that eliminates a square-wave component from the output of the power amplifier.

Disclosed is a distributing cable partial discharge test method based on oscillatory wave test. The method includes that a cable partial discharge testing and locating system based on oscillatory wave test is established; by means of the testing system, a cable is charged through a method of voltage increasing to a preset value at a tested cable end, and damped oscillation voltage is generated at the tested cable end through resonance oscillation that occurs by an inductor and a tested cable capacitor in the system; when partial discharge occurs at a position of the tested cable in a distance from a testing end, pulses can spread in two directions along the cable, and the position where the partial discharge occurs can be determined according to time difference that two pulses such as incident wave and radioactive wave reach the testing end. According to the distributing cable partial discharge test method based on oscillatory wave test, oscillatory wave is applied to partial discharge test of the distributing cable, and voltage increasing is performed on the cable through sine oscillatory wave that is generated by resonance oscillation of fixed inductor and the cable. By means of the distributing cable partial discharge test method based on oscillatory wave test, insulating conditions of the cable can be timely known within short time by the system, and thereby, accidents of the cable can be effectively prevented.

The power supersonic transducer exciting circuit used in biomedicine engineering technology includes two signal generator circuits; gate circuit with first and second inputs connected to the outputs of the signal generator circuits, control end accepting the frequency selecting signal, the third input accepting signal from the protecting circuit and output connected to the input of the driver circuit; driver circuit with output connected to the signal input of serially resonant power amplifier circuit; serially resonant power amplifier circuit with feeding input connected to the voltage output of multiple-stage DC source to output protecting signal to the protecting circuit and signal output connected to the power supersonic transducer to excite it to send supersonic wave. The present invention has simple circuit, easy regulation, controllable output signal amplitude and duty ratio, high transmission efficiency and circuit safety.

The invention provides a wavelet decomposition binary denoising method for the ultrahigh-frequency signal waveform of the partial discharge. The method comprises the steps of 1) arranging a partial-discharge ultrahigh-frequency sensor on to-be-detected power equipment, and acquiring the ultrahigh-frequency signal of the partial discharge by detection equipment; 2) according to a selected mother wavelet and a decomposition level, conducting the multi-scale wavelet decomposition treatment on the signals of the partial discharge to obtain a wavelet coefficient and a signal waveform at each scale; 3) in order to reduce the signal waveform distortion of the partial discharge, processing the coefficient of the wavelet decomposition, calculating the mathematical morphological gradient of the cumulative energy function of signals at each scale, calculating the steepness of the mathematical morphological gradient, comparing the steepness with a preset threshold, deeming the signals at the above scale contain a partial discharge signal and keeping the wavelet coefficient at the above scale to be constant on the condition that the steepness is larger than the preset threshold; or deeming the signals at the above scale only contain noise signals and resetting the wavelet coefficient at the above scale to be zero on the condition that the steepness is not larger than the preset threshold; 4) reconstructing the wavelet according to the processed wavelet coefficient to obtain the denoised ultrahigh-frequency signal of the local discharge.

The invention discloses a sinusoidal gas micro-pressure generator. The generator is characterized by comprising a U-shaped tube, wherein an excitation coil is sleeved outside the bottom tube of the U-shaped tube; an upper permanent magnet is arranged above the excitation coil, while a lower permanent magnet is arranged under the excitation coil, and the excitation coil is connected with an alternating current power supply through a lead wire; and magnetic fluid is filled in the bottom tube of the U-shaped tube, and is full of the bottom tube diameter of the U-shaped tube under the action of the magnetic force of the permanent magnets. The generator has the advantages of low waveform deviation factor, simple structure and easy control.

The invention discloses a transformer substation overvoltage intelligence monitoring system and a transformer substation overvoltage intelligence monitoring method. The transformer substation overvoltage intelligence monitoring method includes following steps: step 1, collecting overvoltage signals, using an overvoltage sensor to detect whether overvoltage occurs, and using the moment when a zero sequence signal component U0(n) exceeds 0.1 as an overvoltage occurrence moment; intercepting a time period tf of 20ms before the overvoltage occurrence moment and a time period tt of 40ms after the overvoltage occurrence moment, using the sum of the time period tf and the time period tt, equal to 60ms, as an overvoltage calculation time period, and using frequency of 200kHz to obtain the zero sequence signal component U0(n) in the overvoltage time period; step 2, extracting time domain features, frequency domain features and time frequency features of the zero sequence signal component U0(n); step 3, performing fault classification on the overvoltage signals. The transformer substation overvoltage intelligence monitoring system and the transformer substation overvoltage intelligence monitoring method are easy to implement, and can automatically perform the fault classification and early warning.

The power generating and monitoring circuit for use in biomedicine engineering and technology consists of exciting signal generator, serial resonant power amplifier circuit, active low-pass filter, controllable DC power source, voltage detecting circuit and current detecting circuit connected together. It is connected with intelligent monitoring system, and the output of the serial resonant power amplifier circuit is connected to the melting electrodes as load. The present invention has simple circuit, convenient regulation, high work efficiency, flexible control, and high measuring and calculating precision of the output power and load impedance.

The invention discloses a method for controlling a vibration hydraulic cylinder of a crystallizer. The method is characterized in that a prediction controller provided with a corrector, an integrally improved PID (proportion integration differentiation) closed loop controller and a valve forward and reverse control method are adopted to calculate the set aperture of a servo valve SPSV, the set aperture of the servo valve at any moment t SPSV (t) is calculated by the following function: SPSV(t)=KPN*SPSV0(t); SPSV0(t)=SPSV1(t)+SPSV2(t); ER(t)=SP(t)-PV(t); and SP(t)=Aset*SP1(t)+Offset. The tracking characteristic of a hydraulic system is good, thus the crystallizer can completely move according to a preset track. The invention has the advantages of stability, reliability, high control accuracy, fast dynamic response and is easy to maintain. The error between the set amplitude and the actual amplitude is small, frequency tracking is stable, wave form distortion and mechanical shock are less.

The invention relates to a variable capacitor array which has excellent controllability on a capacitance value and has variable and high tunability. The variable capacitor array includes a first variable capacitor (C1) having a capacitance which is varied according to application of voltage; a first terminal (O1) connected to one side of the first variable capacitor; a second variable capacitor (C2) having a capacitance which is varied by application of voltage; a second terminal (O2) connected to one side of the second variable capacitor; and a third terminal (I) connected to both of the other side of the first variable capacitor and the other side of the second variable capacitor, wherein a state can be selected by switching between at least two selection states among three selection states of a first selection state that the first terminal (O1) and the third terminal (I) are selected, a second selection state that the second terminal (O2) and the third terminal (I) are selected, and a third selection state that the first selection state and the second selection state are selected simultaneously.

The invention relates to the technical field of acoustic metering and particularly discloses a standing wave pipe coupling cavity used for wide-band low-distortion equal-amplitude equal-phase calibration. The lower end of the standing wave pipe in the standing wave pipe coupling cavity is provided with a loudspeaker, and the loudspeaker is also sealed and fixed by a back end cover; a variable-section reflecting end of which the center is provided with a through hole is sealed and fixed with the upper end of the standing wave pipe, and the coupling cavity with a cylinder structure is sealed and fixed in the center of the upper end of the variable-section reflecting end; moreover, the center of one end of the coupling cavity is provided with a cylindrical groove of which the diameter is the same with the diameter of the circular through hole in the center of the variable-section reflecting end; and a standard microphone and a calibrated microphone are symmetrically installed in the coupling cavity. The design of a variable section is adopted for the coupling cavity, which can provide the effects of stabilizing sound waves with large amplitude and lowering the degree of waveform distortion in the coupling cavity; and meanwhile, the calibration of the sensitivity amplitude and phase of a microphone with high dynamic range, wide frequency range and low distortion degree can be realized by the standing wave pipe coupling cavity, the dynamic range is 94 to 160dB, the frequency range is 500 to 800Hz, the degree of the waveform distortion is smaller than 1 percent, the amplitude consistency bias is smaller than 0.3 percent, and the phase bias is smaller than 0.1 degree.

The invention provides a waveshaping method and device for monitoring data. The method comprises the following steps: the monitoring data is acquired; whether the amount of the motoring data is less than the convention amount in the preset cache time is judged; if the amount of the motoring data is less than the convention amount, the deletion amount between the amount of the motoring data and the convention amount is acquired; uniform interpolation processing is performed to the motoring data according to the deletion amount, and the interpolation data is formed; the wave shape is formed according to the interpolation data. According to the waveshaping method and device for the motoring data, deletion data positions are uniformly distributed in the whole wave shape, and the wave shape distortion influence brought by the deletion data is dispersed, so that the wave shape distortion is reduced, and the accuracy of the wave shape is improved.

An insulation ageing test device of frequency conversion high voltage pulse equipment is prepared as connecting output end of pulse generator to primary edge of high voltage boosting transformer with its secondary edge being connected to wire in insulation sleeve, applying 300H2 to lkH2, 1kH2 to 5kH2 , 5kH2 to 10k H2 and 10k H2 to 20k H2 as operation frequency of high voltage boosting transformer alternately, connecting said boosting transformer to output of pulse generator for outputting square wave to meet requirements of insulation ageing test.

A low-cost magnetic encoder that facilitates generating sinusoidal magnetic flux is provided. First and second permanent magnet arrays each include a plurality of permanent magnets arranged such that magnetic poles having the same polarity face each other, and magnetic yokes disposed on side surfaces of the plurality of permanent magnets. The permanent magnets and the magnetic yokes are arranged side by side at a predetermined pitch in the moving direction of a magnetic piece array. First and second magnetic detectors corresponding to the first and second permanent magnet arrays are disposed in a positional relationship allowing detection of leakage magnetic flux generated when the permanent magnet arrays and the magnetic piece array are displaced with respect to each other.

The invention discloses a three-phase inverter backstepping sliding mode control method and system for achieving the stabilization of a micro-grid, and the method comprises the steps: firstly taking filter capacitor voltage and inductor current as control variables, and building a mathematic model of an inverter system; secondly combining a backstepping method and a sliding mode variable structure method, and building a feedback control model of the inverter system; finally enabling the feedback control model of the inverter system to act on pulse width modulation, and carrying out the control of a three-phase inverter, thereby achieving the three-phase inverter backstepping sliding mode control for achieving the stabilization of the micro-grid. The method gives comprehensive consideration to the reality of the engineering application, is used for the three-phase inverter, is good in steady and dynamic characteristics, is very robust for the parameter perturbation and load disturbance, is suitable for linear, nonlinear and unbalance loads, can be popularized to other different types of three-phase inverters, provides an idea for designing an inverter control system, and is good in prospect of engineering application.

The dynamic balance measuring instrument includes driving motor, driving belt, vibration measuring support, vibration measuring sensor and phase sensor. It features the vibration measuring support comprising two parallel vibration mechanisms, the driving belt driven with motor and installed between the two parallel vibration mechanisms in parallel, the vibration mechanism including base seat with hole and rack with lower end stretched into the hole. The dynamic balance measuring instrument has also air source. The hole inner wall of the base seat has several ventilating holes communicated to the air source. The rack has its lower end suspended inside the hole in the base seat, and the vibration sensor is mounted on the rack. The present invention is suitable for use in high precision, especially super high precision, dynamic balance measurement.

The invention discloses a "sensor adaptive type compound electrical fire monitoring detector ", which comprises a sensor self-identification unit, a sensor sampling, amplifying and filtering unit, a power circuit unit, a voltage zero crossing signal sampling processing unit, a sensor reference voltage stabilizing reference unit, a CAN (Controller Area Network) communication and protection unit, anaudible and visible alarming driving unit and an MCU (Microprogrammed Control Unit) micro processor. The detector can automatically identify the type of a sensor and broken circuit and short circuitstates of a sensor connecting wire and set amplifier circuits having different gains for residual current transducer type sensors or temperature measurement type sensors after the self-identificationis completed; meanwhile, by the arrangement of a two-order active filter and the adoption of a sensor reference voltage stabilizing reference circuit, a voltage zero crossing signal processing technology, a signal shielding technology, a CAN communication bus alarming signal initiative uploading technology and the high-performance MCU micro processor, in cooperation with a relevant software algorithm, the measuring precision and the electromagnetic interference resistance of the detector are greatly improved, the alarming signal uploading time is shortened, mis-alarming of the detector is reduced, and the working stability of the detector is increased.

The invention relates to a pulse switch control device and a control method thereof. The pulse switch control device comprises an H-shaped bridge type transmitted pulse module consisting of a first switch unit, a second switch unit, a third switch unit and a fourth switch unit, and a control module, wherein one diagonal switch group consists of the first switch unit and the fourth switch unit, and the other diagonal switch group consists of the second switch unit and the third switch unit; one opposite switch group consists of the first switch unit and the third switch unit, and the other opposite switch group consists of the second switch unit and the fourth switch unit; the control module is connected with each switch unit respectively; when pulse is transmitted, the control module is used for controlling the switch units in one diagonal switch group to be switched on, and controlling the switch units in the other diagonal switch group to be switched off to form a pulse loop; and when the pulse transmission is stopped, the control module controls the switch units in one opposite switch group to be switched on and controls the switch units in the other opposite switch group to be switched off to form a discharging loop. Due to the formation of the discharging loop, trailing of pulse currents or voltages can be effectively eliminated, and the waveform distortion of the pulse currents or voltages is effectively reduced.

The invention discloses a half-cycle control tri-level single-inductor dual buck half bridge inverter and a control method thereof, belonging to the field of inverters. The inverter comprises a power circuit, a buck circuit and an output filter circuit, wherein the power circuit comprises a first direct current power and a second direct current power, the buck circuit comprises a first buck circuit and a second buck circuit, and the output filter circuit comprises an output filter inductor and an output filter capacitor. The control method of the inverter is as follows: the high level driving signal and the low level driving signal of a power switch tube are obtained by a voltage and current dual ring regulator, thus realizing half-cycle work. The inverter has small volume, light weight, no offset current, small waveform distortion, and high efficiency.

The invention relates to a control method of a photovoltaic LCL type grid-connected inverter. The control method is characterized by comprising the steps of: considering that a photovoltaic LCL type grid-connected inverter system has input uncertainty faults and actuator faults, establishing a fault mathematical model, and setting a fixed control distributive law; establishing a system state high-order sliding-mode observer and state estimation errors thereof according to the fault mathematical model, and adopting the high-order sliding-mode observer for realizing accurate estimation of system fault information; and constructing a continuous integral sliding-mode fault-tolerant controller mathematical model according to the fault mathematical model, the fixed control distributive law, the high-order sliding-mode observer and the state estimation errors thereof, wherein the continuous integral sliding-mode fault-tolerant controller mathematical model is used for processing the actuator faults directly. The control method is reasonable in design, can realize stable control under parameter uncertainty faults and actuator faults, and exhibits good tracking performance and fault tolerance. The control method provides a new idea for the design of a large-scale photovoltaic LCL type grid-connected inverter control system, and has a good engineering application prospect.