222 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 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 discloses a non-isolated DC / DC power converter and a power conversion device, the non-isolated DC / DC power converter comprises a power module and an oscillation suppression module, the power module comprises a first power conversion circuit, the first power conversion circuit is a non-isolated DC / DC conversion circuit, a first output terminal of the first power conversion circuit is connected with a first inductor, and a second output terminal of the first power conversion circuit is connected with a second inductor. A second output terminal of the first power conversion circuit is connected with a second inductor; the oscillation suppression module comprises a second power conversion circuit, a first port of the second power conversion circuit is coupled to the input end of the first power conversion circuit in parallel, and the current of the first port of the second power conversion circuit and at least part of alternating components of the input voltage of the oscillation suppression module are in the same phase. The second power conversion circuit is a bidirectional DC / DC conversion circuit.

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 present application provides an inverter output current DC component detection circuit, which relates to the technical field of inverters. The inverter output current DC component detection circuit provided by the embodiment of the present application directly detects the voltage DC component between the midpoints of the inverter bridge arms to determine whether the inverter output current DC component exists and the size of the DC component, thereby eliminating the influence of the zero drift and temperature drift of the Hall current sensor. The present application designs a first differential amplifier circuit with a low-pass filter function to filter the sinusoidal pulse width modulation voltage between the midpoints of the inverter bridge arms into a sine wave, and realizes the function of filtering out the DC component in the sine wave through a coupling capacitor, realizes the impedance matching of the front and rear stages through a first voltage follower and a second voltage follower, and designs a second differential amplifier circuit with a low-pass filter function to make a difference between the original sinusoidal wave signal and the sinusoidal wave signal with the DC component filtered out, thereby eliminating the AC component and retaining only the DC component, thereby improving the accuracy of detection.

The invention relates to a sending end MMC fault ride-through method, system and device based on virtual impedance and a medium. The method comprises the following steps: generating modulation voltage correction of a three-phase bridge arm in a sending-end MMC by using virtual impedance based on an alternating current component of a bridge arm current in the sending-end MMC; determining the state of the AC side of the sending end MMC based on the AC voltage amplitude of the sending end MMC; when the state of the alternating current side of the sending end MMC is a fault state, the modulation voltage of the three-phase bridge arm is corrected based on the modulation voltage correction amount of the three-phase bridge arm in the sending end MMC, so that the corrected modulation voltage is obtained; and based on the corrected modulation voltage, controlling the sending end MMC to pass through the fault of the alternating current side. According to the invention, when the state of the AC side of the sending end MMC is the fault state, the low-voltage ride-through signal is generated, and the fault ride-through of the AC side of the sending end MMC can be effectively realized by detecting the low-voltage ride-through signal and inputting the virtual resistor, so that the fault low-voltage ride-through capability of the network side of the sending end is improved.

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.

To provide a vibration sensor unit, a rotary electric machine and a pump device that can be used within a wide temperature range and are less likely to cause a failure due to vibration.SOLUTION: A vibration sensor unit 5 includes: a conductor 7 which has at least one coil part 70 wound in a circular coil shape; a body part 6 which is made of a magnetic material and positioned so as to be in contact with the inside of the coil part; a power supply 81 which supplies a constant current to the coil part; and a vibration detection part 822 which detects vibration on the basis of a change in the AC component of the voltage generated in the conductor. A rotating shaft has a cylindrical outer peripheral surface 322. The body part has an annular shape to which the rotating shaft can be inserted or has a shape in which a portion of the annular shape is cut out along a circumferential direction of the coil part. When the rotating shaft is arranged inside the body part so as to rotate in the circumferential direction of the coil part, a portion of the rotating shaft arranged inside the body part is made of a conductive or magnetic material. An inner peripheral surface 61 of the body part is arranged with a gap from the outer peripheral surface of the rotating shaft.SELECTED DRAWING: Figure 2

The utility model discloses a low-voltage driving power supply and a power supply box. The low-voltage driving power supply includes a rectifier filter circuit, a power switch tube, a transformer, a driving chip, an output circuit, an auxiliary power supply and a starting circuit. The power switch tube, the transformer and the driving chip constitute a flyback circuit, which converts the high-voltage direct current output by the rectifier filter circuit into a low-voltage alternating current. The output circuit rectifies the low-voltage alternating current and supplies power to external electrical equipment. The starting circuit provides a starting voltage for the driving chip when the low-voltage driving power supply is started. The starting circuit is provided with a starting capacitor, which is used to filter out the AC component in the starting voltage, improve the stability of the starting voltage, and improve the working stability of the driving chip.

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.

The invention discloses a control method and system suitable for a weak power grid cascade voltage type rectifier. The method comprises the following steps: extracting a d-axis voltage component ed and a q-axis voltage component eq on a d-axis and a q-axis according to circuit parameters of the rectifier; performing AC-DC separation on the voltage component ed to obtain a DC component eddc and an AC component edac of the ed, extracting a feature value B of the AC component edac of the ed, and reconstructing the AC component edac and the q-axis voltage component eq of the ed by using the feature value B to obtain a new AC component edacnew and a new q-axis voltage component eqnew of the ed, then adding the new alternating current component edacnew of the ed and the direct current component eddc of the ed to obtain a new d-axis voltage component ednew; the d-axis current loop output idPI is subtracted from the new d-axis voltage component ednew to obtain ud, the q-axis current loop output iqPI is subtracted from the new q-axis voltage component eqnew to obtain uq, and Park inverse transformation is performed on ud and uq to obtain three-phase modulation waves ua, ub and uc. By adopting the technical scheme of the invention, impedance matching with a power grid can be realized, and the stability margin of a cascade system is 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 discloses an auxiliary power supply EMC universal jittering frequency circuit, comprising a frequency selection module used for determining the frequency of an output sine wave; the in-phase amplification module is electrically connected to the frequency selection module and is used for starting oscillation of the circuit; the normal-phase gain network is electrically connected with the in-phase amplification module and used for being matched with the in-phase amplification module to adjust and self-stabilize the signals; the third capacitor C3 is electrically connected to the output side of the in-phase amplification module and used for removing the direct-current component and leaving an alternating-current component; one end of the output voltage-dividing module is electrically connected to the capacitor C3, the other end of the output voltage-dividing module is grounded, and a voltage-dividing wiring end is used for being connected with the analog control IC and the oscillator at the same time. According to the invention, the EMC radiation interference of the auxiliary power supply of a power supply product of a company can be optimized with relatively low cost.

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.