282 results about "Disturbance voltage" patented technology

An apparatus and method is provided for improving the quality of electrocardiogram (ECG) signals obtained from a patient undergoing magnetic resonance imaging (MRI) wherein the ECG signal has relatively high levels of noise or interference voltages induced on it by changing magnetic fields. The apparatus includes the arrangement of a differential amplifier, a prefilter, a signal limiter (SL) circuit and an intermediate amplifier with an integral low pas filter. The prefilter limits the rise time or high frequency component of the noise or interfering voltages induced on the ECG that are presented to the signal limiter.

A new method for predicting the rotor angle stability status of a power system immediately after a large disturbance is presented. The proposed two stage method involves estimation of the similarity of post-fault voltage trajectories of the generator buses after the disturbance to some pre-identified templates and then prediction of the stability status using a classifier which takes the similarity values calculated at the different generator buses as inputs. The typical bus voltage variation patterns after a disturbance for both stable and unstable situations are identified from a database of simulations using fuzzy C-means clustering algorithm. The same database is used to train a support vector machine classifier which takes proximity of the actual voltage variations to the identified templates as features.

An apparatus for controlling a multi-winding rotary machine including an armature formed of a plurality of winding sets. In the apparatus, a command voltage calculator calculates command voltages to be applied to each winding set so as to control currents detected by a current detector to their respectively corresponding command currents. An interfering voltage calculator calculates, for each of the winding sets, interfering voltages proportional to the rotation speed of the rotary machine. An interfering voltage compensator compensates, for each of the winding sets, the command voltages for their respectively corresponding interfering voltages. An operation unit operates a voltage applicator to apply output values of the interfering voltage compensator to each winding set.

An apparatus for controlling an actuator in a camera module is provided. The apparatus includes a position controller for producing a control voltage to move a lens of the camera module, a hall sensor for detecting an amount of change in magnetic lines of force generated by a magnet as a hall voltage, a voice coil motor for moving the lens according to a current applied thereto, and a current controller for using a voltage applied to the voice coil motor to detect an interference voltage created by the current applied to the voice coil motor, for generating an interference-eliminated hall voltage by removing the interference voltage from the hall voltage, and for controlling the current applied to the voice coil motor based on the control voltage and the interference-eliminated hall voltage.

The invention discloses a method and system for compensating dead zone effects of an inverter of a permanent magnet synchronous motor. The method comprises the steps of real-time collection and synchronous uploading of signals; and on-line compensation of the dead zone effects of the inverter. As for any current sampling period, an analysis and processing process comprises the following steps of collected signal receiving and synchronous saving, analysis and processing time judgment, on-line observation of disturbance voltage of the dead zone effects of the inverter and the compensation of the dead zone effects of the inverter. The system comprises a data processor, a current detection unit, a first signal acquisition circuit, a rotation angle detection unit, a second signal acquisition circuit, a data storage unit and a parameter input unit, wherein the data storage unit and the parameter input unit are respectively connected with the data processor. The method and system is reasonable in design, simple in compensation method and step, convenient to achieve, low in input cost, good in compensation effects and capable of effectively solving the problem that the existing method for compensating dead zone effects of the inverter of the permanent magnet synchronous motor (PMSM) is big in input cost, complex in compensation step, poor in compensation effects and the like.

A disturbance voltage attenuation device can lead high-frequency disturbance voltage in an inverter driving motor system to be obviously inhibited through adopting the effective connection of a passive LC filter network and an active closed loop control circuit. Meanwhile, the disturbance inhibition function of a passive wave filter ensures that the voltage withstand class of an active component is not required overhigh and the cost is lowered; and the closed loop control and the dynamic tracking compensation of the active circuit to the disturbance voltage also lead the design parameter and the volume of the passive component to be greatly reduced.

The invention provides a voltage dip source positioning method based on the disturbance power direction and belongs to automatic monitoring methods for power grid voltage dip source positioning. The method is characterized in that under the effect that a disturbance voltage in a power grid fault process is obtained according to the superposition principle of linear circuits, the direction of an active disturbance power flow is used for accurately positioning a voltage dip source; when active disturbance power is positive, a disturbance source is located at the upstream portion of a monitoring point; when the active disturbance power is negative, the disturbance source is located at the downstream portion of the monitoring point; an algorithm of the corresponding disturbance power is given. The voltage dip source positioning method can be used for certainly positioning voltage dips caused by various power grid faults, is suitable for radiation type or ring type or single-circuit type or two-circuit type or single-power-supply type or multi-power-supply type grid structure power grids, and is also suitable for voltage dip source positioning caused by capacitor switching, transformer switching and large motor starting disturbance; according to the voltage dip source positioning method, the voltage and current of the monitoring point need to be sampled synchronously.

The invention relates to a direct current micro-network line impedance detecting method and device for sagging control. The method comprises the steps that S1 a plurality of groups of disturbance voltage signals are set and used as the reference voltage of a sagging controller; S2 output voltage and output current output by a DC-DC converter are measured; and S3 the line impedance between each distributed energy storage unit and a direct current bus is acquired according to a current-voltage relationship equation and multiple groups of output voltage and output current measured in the step S2; and the line impedance acquired in the step S3 is negatively compensated to the sagging resistor of the corresponding sagging controller. Compared with the prior art, the method and device have the advantages that the accurate measurement of the line impedance is realized without adding any additional measuring device on the basis of traditional sagging control; sagging coefficients are corrected to reduce the influence of the line impedance on sagging control; the load distribution rationality is ensured; the bus voltage quality is improved; and the system stability is improved.

The invention relates to a rock microcrack testing method for testing the deep engineering rock microstructure, including electrolytic solution preparing, rock sample mounting, rock alternating current impedance spectrum data acquisition and data fitting analysis; coating conducting adhesive on the sample for connecting wires, horizontally mounting the sample between containers, and infusing the electrolytic solution in the containers; enveloping mineral butter or ceresin wax on the sample, connecting the wires to the electrochemistry workstation, testing the natural potential of the rock sample tester, zeroing using the electrochemistry workstation; adopting a 5mV disturbance voltage to test the electrochemistry impedance spectrum of the sample, whose frequency range is from 1*10<6>Hz to 0.1Hz; selecting a high-frequency arc frequency range, ciphering the test data points, using the 5mV disturbance voltage to test the sample high-frequency arc electric impedance spectrum, and using the full-frequency band electric impedance spectrum to qualitatively distinguish the size variation of the rock microcracks; according to the high-frequency arc measured data, using ZPLOT to simulate the electrology element numerical values on the high-frequency arc equivalent circuit, calculating the microcrack sizes inside the sample, thereby having the advantages of high accuracy, easy test and convenient operation.

The invention discloses a method and device for eliminating mutual inductance coupling electromagnetic interference; the method of the invention comprises the steps that: after a current signal on the power line of a strong current interference source system is detected and converted into a voltage signal, amplitude amplification is carried out to the normal phase or the reversed phase of the measuring conversion voltage signal and the voltage signal is converted into an output current signal, the value of which is not affected by the load; then the output current signal is converted into an offsetting signal which is equal to an interfering signal in amplitude and contrary to the interfering signal in phase; and the offsetting signal is injected into the loop of a weak current device to offset the interfering voltage inducted by the strong current interference source system to the loop of the weak current device by inductance coupling. The method of the invention dexterously brings in a voltage/current switching circuit, thereby overcoming the influence of the loop impedance of the weak current device on the offsetting effects and enlarging the application scope of the mutual inductance coupling offsetting method. The method and the device of the invention has low power consumption and cost, overcomes the defect that EMI filtering can not remove the interfering signals with the same frequency; compared with a shielding method, hardware devices required by the invention has smaller volume and lighter weight, thus not increasing the difficulty of system layout.

The invention discloses a ground capacitance detection method for a neutral point via arc suppression coil grounding system. A preset type arc suppression coil is in serial or parallel connection with a damping resistor so as to limit the neutral point displacement overvoltage during normal work of a power grid and an electronic power switch is gradually used for rapidly exiting from the damping resistor under the fault state due to the rapid action of the electronic power switch. According to the novel ground capacitance detection method for the preset type arc suppression coil comprising the electronic power switch, the working state of the electronic power switch of the damping resistor is switched through instantaneous control so as to generate the rich frequency component contained disturbance voltage and current pulse and the system ground capacitance is calculated through the disturbance voltage and current signal and the combination with an electronic power disturbance technology based harmonic impedance measurement method for self-tuning of the arc suppression coil.

The invention relates to a method for controlling the small disturbance voltage stability of a microgrid system. The microgrid system controlled by the method comprises a photovoltaic power source, adiesel generator and a DFIG that are connected to one end of a 10kV bus. The control method includes the following steps of: 1) state variable acquisition, including the acquisition of a photovoltaicpower source state variable, the acquisition of a diesel generator state variable, and the acquisition of a DFIG state variable; 2) characteristic value calculation including combining the photovoltaic power source state variable, the diesel generator state variable, and the DFIG state variable to construct a system state space model and to obtain the characteristic value of a system state matrix;3) specific parameter determination including combining the acquired characteristic value and the change trend of a voltage dynamic response curve at a PCC point, and determining the specific parameter affecting the small disturbance voltage stability; and 4) voltage control including improving the specific parameter to improve the small disturbance voltage stability. Compared with the prior art,the method is simple and visual, reduced in cost, and high in control efficiency.

A semiconductor component has interface functions between the controller and the power components of power converters, suitable for gating semiconductor switches. In particular, the semiconductor component serves to gate IGBT and MOSFET power switches in low and medium performance three-phase bridge circuits and integrates signal processing (12), level conversion (16) and amplification (gate driver) (17), error recognition, such as short-circuit monitoring by means of VCE detection (19) and operating voltage monitoring (21) as well as error processing (15) for several power semiconductor switches. The advantages of this gating IC in comparison with hybrid or discrete solutions consist of the high integration density of various digital, analogue and driver functions which result in a reduction in the number of discrete components, which means a lower failure rate of the system and lower costs. Another important consideration is the improvement of switching characteristics thanks to monolithic integration. The integrated circuit is less susceptible to interference voltage and has a lower temperature drift than discrete circuits.

The invention relates to a network for dynamically suppressing power frequency interference of a power transmission line, which belongs to test facilities for electric transmission and transformation equipment. The network is characterized by consisting of an isolation three-phase transformer, a filtering impedor, an interference current suppressing impedor and an interference voltage releasing impedor, wherein the isolation three-phase transformer adopts delta/Y connection; the filtering impedor is connected in parallel with a secondary winding of the isolation three-phase transformer; one end of the interference current suppressing impedor is connected with a non-public end of the secondary winding of the isolation three-phase transformer while the other end is connected with one end of the filtering impedor and a tested circuit end; the interference voltage releasing impedor and the other end of the filtering impedor are connected with a public end of the secondary winding of the isolation three-phase transformer; the filtering impedor, the interference current suppressing impedor and the interference voltage releasing impedor consist of a capacitive reactor and an inductive reactor which are connected in parallel respectively; the filtering impedor and the interference voltage releasing impedor are capacitive; and the interference current suppressing impedor is inductive. The problems of low test result stability, low data reliability and high potential safety hazard of the conventional test facility are solved and the network is used for testing a power frequency parameter of the power transmission line by a pilot frequency method.

The invention discloses a 10 kV voltage class STATCOM testing platform and testing method. The 10 kV voltage class STATCOM testing platform comprises a testing circuit, an adjustable load, a testing instrument, a signal collection bus and a host computer system. According to the 10 kV voltage class STATCOM testing platform and testing method, the host computer system is used for controlling the on-off states of a high-voltage circuit breaker and a low-voltage circuit breaker in the testing circuit, meanwhile, a voltage disturbance generator is controlled to output different disturbance voltages, furthermore, idle work of the adjustable load and work of a harmonic generator device are controlled to be in a reactive-power output or harmonic wave output state, and the performance of STATCOM products which are tested is analyzed through the mode that the testing instrument observes the output of the STATCOM products which are tested; the 10 kV voltage class STATCOM testing platform and testing method are based on a power electronic device of a modularization cascade connection type structure, the structure is simple, and the control is flexible; in addition, the 10 kV voltage class STATCOM testing platform and testing method take all operational conditions of the STATCOM into overall consideration, the adaptive capacity and the compensation effect of the STATCOM which is tested are tested comprehensively, and therefore testing results are comprehensive and dependable.

The invention provides a method for measuring resistance of a ground wire of a transformer. The method comprises the following steps of: 1) allowing the ground wire of the transformer to pass through an N-turn excitation coil and an n-turn response coil, and measuring an interference voltage value Ug output by an output end of the response coil under the condition of not adding excitation voltage signals at the end of the excitation coil; 2) adding an excitation voltage signal Ui with specified frequency and specified amplitude at the input end of the excitation coil, wherein the Ui is coupled to the ground wire so as to generate induction current I on the ground wire; 3) generating response current Io which is equal to I/n by the current I on the ground wire through the response coil, and measuring induction voltage Uo which is equal to Io*Ro and output on the response coil at the time, wherein Ro is the resistance of the output end of the response coil; and 4) obtaining the amplitude of the ground resistance Rx through a formula Ui*Ro/(N*n*(Uo-Ug)). The method of the invention improves the accuracy of measuring the resistance and reduces the influence of the current on the ground wire on the measured resistance.

The invention discloses a photovoltaic inverter MPPT control method based on a three-point comparison method. The method comprises the steps that (1) three-point continuous sampling is performed, wherein a point A, a point B and a point C on a solar cell P-V characteristic curve are selected at will for sampling, the three points are close, the voltage of the point A is U0, the power of the point A is Pa, the voltage of the point B is U0+delta U, the power of the point B is Pb, the voltage of the point C is U0-delta U, and the power of the point C is Pc; (2) the direction of voltage disturbance is judged, if Pa is smaller than Pb, a counter num plus one, or else, the counter num minus one, if Pa is greater than Pc, the counter num plus one, and or else, the counter num minus one; (3) with time T being a period, the magnitude of delta U is changed, and disturbance voltage is changed to the peak value delta Umax. By the adoption of the three-point comparison method, no judgment caused by the change of the external environment can be effectively avoided, and therefore an invertor control system can track the MPP accurately and effectively.

The invention relates to a high tension transmission line comprehensive tester which is structurally characterized in that a data testing calculation unit is connected with a power supply module, a pulse width modulation (PWM) control unit, a direct current constant voltage constant current source, an impedance matching unit, a standard resistor, a measured line resistor, a relay control unit, a storage and printing unit, a display unit and a keyboard. The PWM control unit, the direct current constant voltage constant current source, a power supply filtering unit, the impedance matching unit, the measured line resistor and a standard resistor are sequentially connected. The relay control unit is connected with an interference voltage detection unit and the impedance matching unit. The resistance-capacitance voltage dividing principle is utilized to measure the static induction voltage under 20kV, a disperse Fourier development technology is adopted to test line loop resistance, digital filtering is utilized to remove alternating current components, only direct current components are measured, and direct current voltage of the line can be still measured accurately after alternating current is overlapped. The tester provides accurate data for fixed value setting of a line automatic device and ensures that a power system runs safely and reliably.

The invention belongs to the field of photovoltaic power generation experimental devices and particularly relates to an experimental device and method for tracking photovoltaic maximum power based on an immune genetic algorithm. The experimental device comprises a solar cell panel, a storage battery, a controller, a power component, a load and a monitoring platform; a voltage sensor, a current sensor, a temperature sensor and a radiation quantity sensor transmit signals of voltage, current, temperature and radiation quantity of the solar cell panel to the monitoring platform, and the voltage, the current, power, the temperature and the radiation quantity of the solar cell panel are displayed through a computer on the monitoring platform; output ends of the voltage sensor and the current sensor are connected with the controller, and the controller figures out a maximum power point and the voltage through a self-adaption immune genetic algorithm, outputs a PWM signal to the power component, generates disturbance voltage by changing duty ratio of the PWM signal and controls the output of the solar cell panel to reach the maximum power point.

The invention discloses a conductive common-mode/differential-mode noise separation method, belonging to the technical field of conductive electromagnetic compatibility noise measurement. Radiofrequency current probe measurement and software separation calculation are combined, and the method is suitable for conductive interference measurement on a single phase line. The method comprises the following measuring steps: I, directly measuring a phase line, center line and common-mode conducted interference spectrum by using a radiofrequency current probe, connecting the output end of the current probe to a spectrometer through a coaxial line, and driving the spectrometer to work in a peak detection mode; II, calibrating interference spectrum data obtained in the step I, and measuring the transmission admittance of the current probe and the coaxial line used in the step I by using a vector network analyzer; III, putting the corrected data IL, IN and ICM into a formula to obtain a differential-mode current spectrum IDM so as to obtain the interference voltage in a differential mode and a common mode. By adopting a test method, the conducted interference spectrum on each line can be measured rapidly, and separation of common-mode and differential-mode interference is realized. The method is mainly applied to online measurement of electromagnetic compatibility noise.