154 results about "Ac components" patented technology

The invention relates to an AC-DC integrated grounding fault positioning method and system, and the method comprises the steps: collecting the potential change data of a DC power supply system and the frequency characteristic data of an AC power supply system, and determining the electrical signal characteristics of stray current corrosion; decomposing the electric signal by using wavelet transform, and extracting direct-current and alternating-current components; determining a fault type according to the component amplitude; analyzing the potential gradient and the stray current flow direction in combination with a line topological structure, and determining the position of a fault point; measuring resistance to determine a grounding loop, and analyzing the correlation between corrosion distribution and electrical parameter characteristics; evaluating the influence of corrosion on the grounding path in combination with the material resistivity; according to the method, faults can be accurately recognized, fault points can be accurately positioned, the corrosion degree and the influence of the corrosion degree on the system can be evaluated, and effective support is provided for safe operation and maintenance of a subway power supply system.

The embodiment of the invention discloses a signal switching device and a test system. The signal switching device comprises a coaxial cable input port, a decoupling filter circuit and a media signal output port. The input end of the decoupling filter circuit is connected with the coaxial cable input port, and the alternating current output end of the decoupling filter circuit is connected with the media signal output port; the decoupling filter circuit is used for decoupling the received coupling signal to generate an alternating current component and a direct current component, the alternating current component is a media signal, and the direct current component is a power component; and the media signal output port is used for outputting the alternating current component decoupled by the decoupling filter circuit. According to the device provided by the invention, the DC component in the transmission coupling signal in the coaxial cable can be decoupled through the decoupling filter circuit, so that the test process is simplified, and the test cost is reduced.

The invention belongs to the technical field of nondestructive defect detection, and particularly relates to a method for detecting cracks in any direction in carbon steel based on magnetic resistance disturbance. The crack detection method comprises the following steps: applying a static magnetic field to magnetically conduct a carbon steel structure to a high-sensitivity stage; and then exciting an alternating-current magnetic field in an excitation range defined on the surface of the carbon steel structure to be detected, and counting the change condition of the magnetic conductivity of the carbon steel structure, so that effective identification and detection of internal cracks in any direction are realized. The crack detection method comprises the following steps of: magnetizing a carbon steel structure to be detected to the left side of a peak value of a magnetic conductivity curve by using a static magnetic field B0; defining an excitation range on the surface of the carbon steel structure to be detected, and exciting an alternating current magnetic field B1 in the excitation range; collecting an alternating current magnetic field B1 and a secondary alternating current magnetic field B2 in the excitation range, and converting to obtain a signal Bx; obtaining an alternating current component JBx and a direct current component ZBx; and moving the alternating-current magnetic field B1 in the excitation range, and counting the change trend of the alternating-current component JBx.

The utility model discloses an arc discharge detection system, and belongs to the technical field of circuit detection. The system comprises a current sampling device, a band-pass filter circuit, a signal generation circuit and an operational circuit, the sampling end of the current sampling device is connected with a line to be detected, and the output end of the current sampling device is connected with the input end of the band-pass filter circuit; the output end of the band-pass filter circuit is connected with the first input end of the operational circuit; the output end of the signal generation circuit is connected with the second input end of the operational circuit, and the signal generation circuit is used for outputting a reference AC component signal; the operational circuit is used for subtracting the AC component signal input by the first input end from the reference AC component signal input by the second input end, a subtraction result is output through the output end of the operational circuit, and the subtraction result is used for indicating whether arc discharge exists in the line to be detected or not. And arc discharge detection of the circuit can be realized.

The invention discloses a direct current arc discharge detection method and device of a photovoltaic inverter, a medium and equipment, and belongs to the technical field of arc detection. The method comprises the following steps: acquiring an alternating current component current of a direct current side current of the photovoltaic inverter by using a current sensor, converting the alternating current component current through a hardware circuit to obtain a direct current voltage signal, and sequentially performing signal amplification processing and band-pass filtering processing on the direct current voltage signal to obtain a processed signal of which switching noise is filtered; a microcontroller is used for sampling the processed signal after the switching noise is filtered out, fast Fourier transform is carried out on the sampled processed signal, and frequency spectrum data of the processed signal are obtained; calculating to obtain a corresponding power spectrum by using the frequency spectrum data of the processed signal; and processing the power spectrum by using the neural network model so as to judge whether the arc discharge phenomenon is generated on the direct current side of the photovoltaic inverter. According to the invention, high-precision and high-robustness identification of the direct-current arc under the complex working condition is realized.

The invention discloses a bus current ripple suppression method and device and a medium. The method comprises the following steps: acquiring electric quantity data of each direct current booster circuit in a current operation state in real time; based on the obtained electric quantity data, calculating a phase shift angle required by each path of direct-current booster circuit by taking the minimum total alternating-current component output to the direct-current bus by all the direct-current booster circuits as a target; and carrying out phase modulation on the driving signals of the direct current booster circuits according to the obtained phase shift angles. The device and the medium are both used for implementing the method. The bus current ripple suppression method and device have the advantages that in the bus current ripple suppression process, the phase shift angle can be made to change dynamically instead of being fixed, and therefore the problem that the bus current ripple suppression effect is poor when the input voltage and current are different is solved. And the minimum current ripple fundamental component or the current ripple effective value is directly selected as an optimization target, so that the heating value of the system can be effectively reduced.

The invention discloses an MMC fault current rise rate calculation method and a related device, and the method considers an AC rise component determined by an AC output parameter and a DC rise component determined by a DC side operation parameter, and can comprehensively reflect the fault response characteristics of an MMC under different working conditions. A final fault current rise rate is calculated through superposition of an alternating current component and a direct current component, traditional simulation dependence is avoided, and rapid calculation and protection setting in a project are facilitated; according to the calculation method provided by the invention, the rise rate is directly calculated based on measurable operation parameters and known equipment parameters, simulation modeling or waveform fitting is not needed, and the real-time performance and applicability of fault analysis are improved; the method provided by the invention does not depend on a specific control strategy, is suitable for an MMC structure in a symmetric or asymmetric operation mode, and has good universality and engineering generalization performance.

The application discloses a motor control method, a controller, a motor, a refrigerator, a medium and a program product. A direct-current bus voltage and a cross-axis current of a motor are acquired, and a direct-axis voltage and a cross-axis voltage are acquired. An initial direct-axis current is generated through field weakening control according to the direct-axis voltage, the cross-axis voltage and the direct-current bus voltage. A target frequency disturbance component caused by direct-current bus voltage fluctuation and a direct-current component used for field weakening control are separated from the initial direct-axis current. A phase of the target frequency disturbance component is calculated and optimized to obtain a target alternating current component, with minimization of a harmonic component of the target frequency in the cross-axis current as an optimization target. A direct-axis reference current is synthesized according to the target alternating current component and the direct-current component, and the motor is controlled according to the direct-axis reference current. In the working condition of the direct-current bus voltage fluctuation, energy backflow can be effectively inhibited, current harmonics can be reduced, torque pulsation can be reduced, and the running stability of the motor can be improved.

To provide a controller for a rotary electric machine and an electric power steering apparatus which can suppress the error increase of the rotational angle due to the high frequency noise component included in the current detection value, while reducing the AC component error included in the sensor detection value of rotational angle, at high rotational speed. A controller for a rotary electric machine estimates an estimation actual angle deviation; calculates a detection angle deviation; calculates a control angle deviation by dividing internally between the estimation actual angle deviation and the detection angle deviation; calculates a rotational angle for control by performing feedback control so that the control angle deviation approaches 0; and makes the ratio of the estimation actual angle deviation higher than the ratio of the detection angle deviation, when the rotational speed is higher than a speed threshold value.

Systems and methods are described for applying one or more frequency domain analyses to AC components to automatically discriminate between different operating conditions of the power architecture. Embodiments can then adaptively adjust the voltage (e.g., and current) to reduce or eliminate extra power consumption based on the detected operating condition. In some embodiments, the frequency domain analyses are based on fast Fourier transform (FFT) techniques and / or total harmonic distortion (THD) techniques. Embodiments can be applied to internal power modules and / or to external power adapters.

The present application relates to a buffer circuit, a signal acquisition device and an electronic device, wherein the buffer circuit includes a first power supply module, an operational amplifier module and a second power supply module. The first input end of the operational amplifier module is used to receive a bioelectric signal, and the output end of the operational amplifier module is respectively connected to the second input end of the operational amplifier module, the first power supply end of the operational amplifier module and the first power supply module. The difference between the first AC component output by the operational amplifier module according to the bioelectric signal and the voltage value of the bioelectric signal and the first power supply is within a first preset range; the input end of the second power supply module is connected to the output end of the operational amplifier module, and the output end of the second power supply module is connected to the second power supply end of the operational amplifier module. The difference between the second AC component output by the second power supply module to the operational amplifier module according to the first AC component and the voltage value of the bioelectric signal is within a second preset range. The first preset range and the second preset range are adjusted so that the first AC signal and the second AC signal are closer to the bioelectric signal and the input impedance is increased.

Disclosed are a high power flux cancelling current steering inductor without a gap and processes of making and using same. When properly configured and wired such inductors, separate the AC component and DC component of a high power current thus allowing the smaller AC fraction of the overall current to be carried by much smaller cross-sectional litz wires. Such a high power flux cancelling current steering inductor without a gap are more efficient at avoiding core saturation compared to standard inductors, do not require core gaps, yet they are less expensive without the need for large cross-sectional litz AC carrying wires. In addition to the aforementioned benefits, such a high power flux cancelling current steering inductor without a gap permits the levels of AC and DC current to be efficiently monitored as such currents are separated.

The invention discloses a water electrolysis hydrogen production system and a cold start control method, and belongs to the technical field of water electrolysis hydrogen production. A water electrolysis hydrogen production system comprises an electrolytic bath and further comprises a modulated hydrogen power source for providing electric energy for the electrolytic bath, the modulated hydrogen power source is used for providing current with adjustable alternating current and direct current components for the electrolytic bath, and the numerical value of the direct current component is larger than or equal to the maximum value of the alternating current component. The direct-current component is used for participating in a polarization reaction of electrolytic hydrogen production, and the alternating-current component is used for additionally heating the electrolytic cell in a cold start process. According to the water electrolysis hydrogen production system, by specially increasing the alternating current component proportion and / or frequency of the output current of the hydrogen production power supply, namely increasing the active power generated by the alternating current component, more power supply output power is used for heating the electrolytic cell; therefore, the temperature rise starting performance of the hydrogen production system is greatly improved on the basis of not changing the technological process of the hydrogen production system and not increasing additional system auxiliary machine parts.

The invention discloses a multi-level current source inverter and a control method thereof, and relates to the field of electric energy conversion control, the multi-level current source inverter is composed of an MCSI module, a direct current side inductor, a coupling capacitor, a ripple filter and a control module, and the three-phase voltage and the load current of a power grid are measured; calculating a reference phase under a synchronous rotating coordinate system by using a three-phase digital phase-locked loop, and further decomposing the reference phase into a current mean value and an alternating current component; a current error is obtained by establishing an additional control loop, and a DC component is separated from the current error by using a PI controller; generating a reference current under the synchronous rotating coordinate system, converting the reference current back to the three-phase coordinate system, and generating an actual gate driving signal of the MCSI module; based on an actual gate pole driving signal, the actual gate pole driving signal serves as a reference of phase shift carrier SPWM, and zero-state selection and inductive current balance are optimized in cooperation with a logic state machine. The method is used for power quality management of the power distribution network, harmonic waves and reactive power can be suppressed, and switching loss is reduced.

The utility model relates to a confluence cabinet body structure, a confluence cabinet and an energy storage container, a shell in the confluence cabinet body structure is provided with a first accommodating cavity and a second accommodating cavity, the second accommodating cavity is arranged above the first accommodating cavity, the first accommodating cavity is used for accommodating a direct current assembly, the direct current assembly comprises a conducting bar group, and the conducting bar group is used for connecting a first wire harness; the second accommodating cavity is used for accommodating the first alternating current component and the communication component, so that reasonable layout of the direct current component, the first alternating current component and the communication component is realized, different types of devices have a certain distance in space, and the power supply and communication reliability of the confluence cabinet is improved; by setting the distance between the conducting bar group and the bottom surface of the shell, the operation space is large, and an operator can conveniently assemble and maintain the conducting bar group; in addition, when the first wire harness extends into the first accommodating cavity, enough space is provided for bending in the first accommodating cavity, so that the first wire harness is electrically connected with the conducting bar group, and the maintainability of the confluence cabinet is improved.

A method for detecting particles in a gas of a process environment present in a process chamber, the method comprising the steps of: guiding the gas with the particles into an ionization and charging unit (11) being in fluid communication with the process chamber, wherein the ionization and charging unit has an anode (12) and a cathode (13) and is adapted and configured to at least partly ionize said gas and to charge at least some of said particles; igniting and sustaining a discharge in said gas by applying a voltage between said anode and said cathode of the ionization and charging unit; measuring a current flowing from or to the anode and / or from and to the cathode; detecting the particles based on an AC component or a transient of the measured current. The invention is further directed to an apparatus for detecting particles, to a coating system comprising such an apparatus and to a use of ionization unit.

[Problem] To compensate power pulsation generated in a DC link unit with a device provided in the DC link unit when a system interconnection inverter connected to the DC link unit and interconnected with a three-phase system power supply outputs three-phase unbalanced power. [Solution] A control device controls one or a plurality of devices that transmits first DC power to a DC link unit or receive the first DC power from the DC link unit. The first DC power includes first power pulsation, which is an AC component. The DC link unit is configured to be capable of transmitting and receiving second DC power to and from a system interconnection inverter that is connected to the DC link unit and interconnects with a three-phase system power supply. The control device includes a pulsation detection unit that detects a second power pulsation, which is an AC component included in a second DC power, and adjusts the first power pulsation according to the second power pulsation detected by the pulsation detection unit.

A common voltage loading analog circuit and a display device are provided. The common voltage loading analog circuit includes a circuit unit to be tested, a load simulation circuit unit, and an auxiliary circuit unit. The load simulation circuit unit includes a signal generator, an amplifier circuit, and a resistance-capacitor series circuit. Through the resistance-capacitor series circuit, an AC component in the output voltage of the load simulation circuit unit can be completely filtered out to the input terminal of the circuit unit to be tested, and then a DC component output from the auxiliary circuit unit to the input terminal of the circuit unit to be tested is superimposed, which makes the voltage at the input terminal of the circuit unit to be tested consistent with the output voltage of the load simulation circuit unit, without attenuation.

The invention discloses a non-isolated DC / DC power converter and a power conversion apparatus. The non-isolated DC / DC power converter comprises a power module comprising a first power conversion circuit, the first power conversion circuit being a non-isolated DC / DC conversion circuit, a first output end of the first power conversion circuit is connected with a first inductor, and a second output end of the first power conversion circuit is connected with a second inductor; and an oscillation suppression module comprising a second power conversion circuit, a first terminal of the second power conversion circuit coupled in parallel to an input end of the first power conversion circuit, a first terminal current of the second power conversion circuit being in phase with at least partial of AC components of an input voltage of the oscillation suppression module, and the second power conversion circuit being a bidirectional DC / DC conversion circuit.

The invention relates to an MMC-based multi-terminal interlaced direct current power flow controller, which comprises an MMC circuit and a control module which are connected with each other, the MMC circuit is a multi-port network and comprises a direct current bus capacitor and a converter which are connected with each other, the converter comprises converter branches of which the number is the same as that of ports, and the converter branches are connected with the control module. Each converter branch comprises an upper arm and a lower arm which are connected to the midpoint of the converter branch, the midpoint of each converter branch provides the port outwards, and each arm comprises N submodules which are in cascade connection, the control module obtains PWM pulse signals of the sub-modules through external power flow control, internal power flow control and module capacitance balance control. Compared with the prior art, power distribution control among multiple power transmission lines in the high-voltage direct-current power transmission network is realized, and the method has the advantages of higher output voltage level, stronger robustness, less alternating-current component injection in the power transmission lines and the like.

This invention discloses an active damping control structure and method for a DC transformer and a DC distribution network, belonging to the field of DC transformer control technology. In the control structure: a summation module sums the input voltages of M sub-modules to obtain voltage v. bus The filter module filters out voltage v bus The AC component in the equation yields the DC voltage v. DC The averaging module calculates the voltage v respectively. bus and DC voltage v DC Divide by M to obtain the reference value v avg and reference value v DCref The input voltage equalization controller realizes the input voltage v of each submodule j. in_j Compared with reference value v avg Zero steady-state error regulation, output power p ivs_j The input voltage regulator controller implements the input voltage v of each submodule j. in_j Compared with reference value v DCref Zero steady-state error regulation, output power p ivr_j The output voltage regulator achieves the output voltage V. o Compared with reference value V oref Zero steady-state error regulation, output power regulation p ove The actual power calculator calculates the actual power of each submodule j using the instruction p. pu_j The control structure and method of this invention ensure stable operation of the transformer.

The invention relates to an electromagnetic coil induction signal temperature drift error compensation device and a compensation method. A constant current source, a direct current component output circuit, an alternating current component output circuit and a detection circuit are respectively arranged on a secondary electromagnetic coil and a compensation electromagnetic coil; after a direct current signal is injected, an output signal of a corresponding electromagnetic coil is filtered to separate a direct current component signal and an alternating current component signal, a sampling voltage is detected according to the alternating current component signal, and finally a data processing module carries out secondary induction signal compensation and compensation induction signal compensation respectively. According to the device, a temperature measurement platinum resistor does not need to be additionally arranged in the sensor to compensate the temperature drift of an induction signal of the sensor, so that the complexity of structural composition of the sensor can be reduced, a poor compensation effect caused by medium attenuation and non-uniform medium thermal conductivity in a conduction process of platinum resistor temperature measurement is avoided, and the compensation accuracy is improved.

The present invention discloses an AC / DC voltage transformer, comprising: a high-voltage arm and a low-voltage arm. The low-voltage arm includes: a voltage limiting branch, a total voltage sampling branch, a DC component sampling branch, and an AC component sampling branch. The high-voltage end of the high-voltage arm is connected to the voltage to be measured, and the low-voltage end is connected to the high-voltage end of the low-voltage arm. The low-voltage end of the low-voltage arm is grounded. One end of the voltage limiting branch is connected to the high-voltage end of the low-voltage arm, and the other end is connected to the low-voltage end of the low-voltage arm. One end of the total voltage sampling branch is connected to the high-voltage end of the low-voltage arm, and the other end is connected to the low-voltage end of the low-voltage arm. One end of the DC component sampling branch is connected to the high-voltage end of the low-voltage arm, and the other end is connected to the low-voltage end of the low-voltage arm. One end of the AC component sampling branch is connected to the high-voltage end of the low-voltage arm, and the other end is connected to the low-voltage end of the low-voltage arm. The present invention can measure the DC, AC, and total voltage values of the voltage to be measured using only one primary device, effectively reducing the cost and improving the measurement efficiency.

The invention discloses a copper loss minimum control system and method for a variable flux reluctance motor, and the method comprises the steps: converting the electric energy of a DC power supply into a six-phase "AC + DC" mixed current through a six-phase winding and a six-phase inverter, superposing a positive polarity DC voltage (+ Vdc) according to A, C and E phases, and superposing a negative polarity DC voltage (-Vdc) according to B, D and F phases, thereby forming a positive and negative symmetrical current superposition structure. A DSP controller is adopted to carry out dq conversion to obtain a d-axis current component and a q-axis current component; pI control is adopted to generate instruction voltage, the amplitude of a direct current component and the amplitude of an alternating current component of a DC current component and the amplitude of an AC current component are dynamically adjusted, Idc: Iac = 1: 2, the phase current effective value Is = Idc2 + Idc22 is minimum at the moment, and copper loss minimization is achieved. The method does not need an independent magnetic coil, simplifies the structure, improves the efficiency, is suitable for high-efficiency operation in a wide rotating speed range, and is especially suitable for electric vehicles and other scenes with high motor efficiency requirements.

The invention discloses a ground resistivity observation system detection device, and belongs to the technical field of detection equipment, the ground resistivity observation system detection device comprises a shell and a test panel, the test panel is detachably installed in the shell, the front side of the shell is provided with a lock catch mechanism, the rear side of the shell is hinged with a cover body, the front side of the cover body is fixedly provided with a lock catch seat, and the lock catch seat is fixedly connected with the lock catch mechanism. A lock catch mechanism is arranged in the shell and matched with the lock catch base, a locking mechanism is arranged in the shell and comprises a conical shell and two locking rods, and balls are arranged in the conical shell. According to the invention, a DC / AC voltmeter, an ammeter and a special detection interface are integrated, and one-stop testing of core parameters such as current stability, ripple coefficients and system errors is synchronously supported. The ripple detection loop extracts an alternating current component through capacitor filtering, error calibration adopts a standard resistance comparison method, multichannel data is acquired in parallel, error accumulation caused by repeated wiring is avoided, the detection period is remarkably shortened, and the data consistency is improved.

The application discloses a kind of compensation current adjustable transimpedance amplification circuit, including reference voltage circuit, bipolar direct current circuit, voltage-current conversion circuit and transimpedance amplification circuit.First, reference voltage circuit generates high-precision, low-noise reference voltage, then through bipolar direct current circuit, it is converted into certain voltage within positive and negative reference voltage by reference voltage, and the voltage also has the characteristics of high-precision low-noise, then the voltage is converted into compensation current by voltage-current conversion circuit, and finally, through transimpedance amplification circuit, the AC component is converted into voltage signal output by offsetting direct current component.The application can realize high-precision current compensation, and has the characteristics of low noise.The circuit of the application can be used in inertial measurement device, magnetometer and other precision optoelectronic measurement fields.

This invention discloses an active simulation system and method for harsh ground planes in DC testing, belonging to the field of electromagnetic environment simulation technology in electrical testing. The system employs a dual DC source architecture with a grounding switch. Two DC sources are connected to the DC power supply circuit of the device under test (DUT), and the grounding switch enables controllable switching between the dual DC sources and the ground plane. By configuring the DC output of the two DC sources and superimposing controllable ripple, while ensuring zero AC component of the voltage between the positive and negative terminals of the DUT and stable power supply, the voltage between the ground plane and the negative terminal of the DUT forms independently adjustable DC and AC components. It also provides two implementation architectures that can flexibly adapt to different testing scenarios. This invention achieves full-parameter active controllable simulation of harsh DC ground planes, accurately reproducing the actual operating conditions of DC tests such as power batteries, motor test benches, and high-power charging and discharging, significantly improving test quality and the verification accuracy of the safety and reliability of the DUT.

The present application discloses a failure detection circuit and a failure detection device, which includes a switching circuit, a bias control circuit, and a fault detection circuit. The switching circuit has a first terminal, a second terminal, and a control terminal, and connects or disconnects the first and second terminals according to a control terminal voltage. The bias control circuit is coupled to the switching circuit and changes the control terminal voltage according to a fault signal. The fault detection circuit is coupled to the bias control circuit, detects an AC component in the control terminal voltage, and generates a fault signal according to the AC component. The fault detection circuit receives a detection signal, compares the detection signal, and generates a detection result signal. When the detection result signal is a fixed level signal or non-ripple signal, the fault detection circuit generates a fault signal.

The invention relates to a method for determining a motor constant (Km) of an electric machine (7), in particular an actuator arrangement (6), wherein at least one excitation signal (Im) with at least one DC component (I0) and one AC component (Ik) is specified, wherein the machine (7) is controlled with the excitation signal (Im), wherein at least one actual value of a motor current of the machine (7) and one actual value of a rotation rate (ω) of a rotor shaft of the machine (7) are determined, and wherein the motor constant (Km) is determined as a function of the excitation signal (Im) and the actual values.

This invention discloses a method and system for analyzing circuit breaker breaking parameters based on phase domain trajectory analysis. The method includes: first, constructing a time-domain waveform expression for the short-circuit current; after acquiring the fault waveform, mapping the time-domain sampling points to the polar coordinate plane by defining reference points and sampling windows to form a phase domain trajectory and drawing it; then, performing waveform reproduction and similarity analysis, adjusting the initial phase of the sinusoidal AC component and the attenuated DC component to reproduce a high-precision time-domain waveform and improve the short-circuit current time-domain waveform expression; next, using vectorized matching technology based on digital channel names and kurtosis algorithms to screen out associated circuit breakers with displacement in the fault recording; then, calculating key parameters such as the DC time constant, fault current duration, and RMS value of the total current, and comparing and verifying them with the rated parameters of the circuit breaker. This improves the accuracy and real-time performance of circuit breaker breaking capacity assessment, providing an efficient and automated method for circuit breaker performance evaluation and anomaly diagnosis after power grid faults.