89 results about "Ac components" patented technology

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.

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.

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.

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 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.

A test and measurement probe system, including an input to receive an input signal, the input signal including a low frequency (LF) and / or direct current (DC) component and an alternating current (AC) component, an extractor circuit, such as an AC coupling circuit or a LF and / or DC rejection circuit, configured to receive the input signal and to separate the AC component and the LF and / or DC component from the input signal, a first output to output the alternating current component to the test and measurement instrument, and a second output to output the direct current component to the test and measurement instrument. In some embodiments, the LF and / or DC component is digitized prior to being output by the second output.

This invention discloses a DC suppression circuit structure, a DC suppression method, and a terahertz heterodyne detection system. The DC suppression circuit structure includes a first nonlinear detection module, a second nonlinear detection module, a phase adjustment module, and a signal synthesis module. The phase adjustment module adjusts the phase of the mixing signal generated by the second nonlinear detection module. The signal synthesis module superimposes the phase-adjusted mixing signal with the mixing signal generated by the first nonlinear detection module. During the synthesis process, the self-mixing DC component is at least partially canceled out, and the intermediate frequency AC component is at least partially superimposed. This invention weakens or cancels the self-mixing DC component during the synthesis process, while allowing the intermediate frequency AC component to be superimposed and output, thereby effectively suppressing the self-mixing DC component in the output signal and improving the stability of the intermediate frequency signal.

The application belongs to the field of direct current transmission and relates to a sine modulation compensation method and system for a hybrid direct current energy consumption device, which comprises the following steps: obtaining an energy consumption valve sine modulation voltage according to surplus power of the hybrid direct current energy consumption device; if the energy consumption valve sine modulation voltage is negative, analyzing the cause of power imbalance of the energy consumption valve based on voltage non-negativity of a half-bridge energy consumption unit; and according to the cause of power imbalance of the device, expanding a compensation factor y through an alternating current component and reducing a compensation factor x through a direct current component, so as to ensure that the discharge energy and the charging energy of the energy consumption valve in a unit period are equivalent, and the average power of the energy consumption resistor in a unit period is equivalent to the surplus power. The method can effectively reduce the number of power devices of the hybrid direct current energy consumption device, greatly reduce the volume and cost of the hybrid direct current energy consumption device, and has great practical value and broad application prospect in the field of offshore wind power transmission through flexible direct current.

[Problem] To adjust power pulsation caused to a DC link unit due to fluctuations in power consumption of electrical equipment connected to the DC link unit. [Solution] This control device controls one or more converters for transmitting first DC power to a DC link unit. The first DC power includes a first power pulsation, which is an AC component. The DC link unit is configured to be capable of transmitting second DC power to electrical equipment connected to the DC link unit. The control device comprises a pulsation acquisition unit for acquiring a second power pulsation, which is an AC component included in the second DC power, and adjusts the first power pulsation in accordance with the second power pulsation acquired by the pulsation acquisition unit.

A motor drive device (1) includes: a converter section (11) that converts input AC power into DC power to output to a DC link; a DC link capacitor (4); voltage dividing resistors (13-1, 13-2) that are connected in series to each other between a positive potential line and a negative potential line of the DC link; a measurement resistor (14) that is connected between a connection point of the voltage dividing resistors (13-1, 13-2) and the positive potential line or the negative potential line of the DC link; a resistor voltage measurement section (15) that measures a resistor voltage of the measurement resistor (14); a DC component extraction section (16) that extracts a DC component of the resistor voltage; an AC component extraction section (17) that extracts an AC component of the resistor voltage; a DC link potential measurement section (18) that measures the positive potential and the negative potential of the DC link; and an insulation resistance value calculation section (19) that calculates an insulation resistance value of a motor (3) based on the DC component and the AC component of the resistor voltage and the positive potential and the negative potential of the DC link.

In order to constantly remain stable during a transient response at the time of regenerative braking by an electric vehicle using a DC power source and increase regenerative electric power, this control device for an inverter which converts, into AC power, DC power supplied from the DC power source and smoothed via a smoothing capacitor to drive a motor comprises: a generation unit for generating a first motor current operation amount by extracting an AC component of a smoothing capacitor voltage detected from the smoothing capacitor; a generation unit for generating a second motor current command value according to the smoothing capacitor voltage; a generation unit for generating a second motor current operation amount by smoothing the difference between a set first motor current command value and the second motor current command value; and an update unit for updating the first motor current command value by adding the sum of the first motor current operation amount and the second motor current operation amount to the first motor current command value. The control device for the inverter controls an output voltage of the inverter on the basis of a motor current detection value of the motor and the updated first motor current command value.

A monitoring arrangement for monitoring a parameter value associated with an AC supply or an AC component of a supply in a distribution network. The monitoring arrangement includes a sensor arrangement electrically connected, in use, to the network or otherwise monitoring the network, and a control unit operable to use the output of the sensor arrangement to determine, for a voltage, an amplitude value for a selected frequency. The method allows the operation of the device to be controlled depending on the supply from the network, without relying on signal components from rotating power converters.

When a grid-connected inverter, which is connected to the DC link section and interconnected with a three-phase grid power supply, outputs three-phase unbalanced power, the power pulsation that occurs in the DC link section is compensated for by equipment installed in the DC link section. [Solution] The control device controls one or more devices that transmit first DC power to or receive first DC power from the DC link section. The first DC power includes a first power pulsation which is an AC component. The DC link section is configured to transmit and receive second DC power between the DC link section and a grid-connected inverter connected to the DC link section and a three-phase grid power supply. The control device includes a pulsation detection unit that detects a second power pulsation which is an AC component included in the second DC power, and adjusts the first power pulsation according to the second power pulsation detected by the pulsation detection unit.

The power pulsation of the DC link section caused by fluctuations in the power consumption of electrical equipment connected to the DC link section is adjusted. [Solution] The control device is a control device that controls one or more converters that transmit first DC power to a DC link unit, where the first DC power includes a first power pulsation that is an AC component, and the DC link unit is configured to be able to transmit second DC power to an electrical device connected to the DC link unit, and the control device has a pulsation acquisition unit that acquires second power pulsation that is an AC component included in the second DC power, and adjusts the first power pulsation according to the second power pulsation acquired by the pulsation acquisition unit.

This phase shifter 10 comprises an input terminal T1, a variable phase shifter 12, a distributor 14, a mixer 15, an LPF 16, and an output terminal T2. The variable phase shifter 12 is configured to change a phase of a first electric signal input to the input terminal T1 by a phase rotation amount corresponding to a phase shift adjustment voltage Vp. The distributor 14 is configured to distribute the first electric signal having the phase changed by the variable phase shifter 12 to the output terminal T2 and the mixer. The mixer 15 is configured to output, as a third electric signal, an electric signal obtained by multiplying the first electric signal distributed by the distributor 14 with a second electric signal which is the same electric signal as the first electric signal supplied from another phase shifter but having the phase rotated by the other phase shifter, to the LPF 16. The LPF 16 is configured to remove an AC component from the third electric signal from the mixer 15 and output a fourth electric signal after the removal.

The invention 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 relates to a load-flow controller (1) for a DC network (10). In order to improve existing load-flow controllers, according to the invention the load-flow controller (1) has four voltage sources (61, 62, 63, 64), the load-flow controller (1) additionally having a first current path (71) and a second current path (72) which are in each case configured in such a way as to suppress a direct current through the relevant current path (71, 72), wherein the voltage sources (61, 62, 63, 64) are each designed to generate a voltage having a DC component and an AC component. The invention further relates to a DC network (10) having such a load-flow controller (1), a first DC sub-network (11) and two lines (8), wherein the DC sub-network(11) is electrically connected to a network connection (4), wherein a first line of the two lines (8) is electrically connected to a first transmission connection (41) and a second line of the two lines (8) is electrically connected to a second transmission connection (42). The invention further relates to a method for operating such a load-flow controller (1) or such a DC network (10), wherein a DC component is in each case generated by the voltage sources (61, 62, 63, 64) as a function of a first direct current (i DC,1) between the network connection (4) and the first transmission connection (41) and / or a second DC current (iDC,2) between the network connection (4) and the second transmission connection (42), wherein the voltage sources (61, 62, 63, 64) furthermore in each case generate an AC component, wherein the AC components of the voltage sources (61, 62, 63, 64) are configured in such a way that these AC components compensate one another in pairs in a voltage between the first network connection and the transmission connection (41, 42), wherein the AC component is generated in such a way as to counteract in at least some of the voltage sources (61, 62, 63, 64) an energy exchange caused by the DC component.