1179 results about "Ac current" patented technology

A system includes: an alternating current (AC) to direct current (DC) converter (AC-DC converter), the AC-DC converter connectable to a line voltage; and a DC to DC converter (DC-DC converter) connected to the AC-DC converter, the DC-DC converter including: a high voltage buck-boost converter having a secondary side connectable to a high voltage battery; a low voltage buck-boost converter having a secondary side connectable to a low voltage battery; and one or more transformers having a primary side connected to the AC-DC converter, a secondary side connected to a primary side of the high voltage buck-boost converter, and a tertiary side connected to a primary side of the low voltage buck-boost converter.

A charging bench includes three coils that partially overlap, in superposed planes. An electrical feed makes it possible to supply the coils with an AC current from the mains. A portable device to be charged is placed on the upper side of this charging bench. This device includes a winding intended to receive the electrical charging, and a ferrite protective screen. One of the coils (Bb) is selected to emit the magnetic charging flux toward the mobile phone. The selection is carried out via the emission of a series of pulses by at least one of the coils and comparison of return signals with a reference threshold. This comparison also enables one of the other coils (Ba, Bc) to be selected or both of these other two coils (Ba, Bc) to be used to receive a flux for communicating information originating from the portable device to be charged.

The invention provides a device and method for testing the reliability of a power sensor, and the device comprises a magnetic field generation unit which is used for providing an alternating current for a Helmholtz coil through a power frequency current source, and generating a controllable magnetic field; the electric field generating unit is used for providing a high-voltage direct current or power frequency alternating current power supply for the parallel-plate capacitor through a high-voltage generator to generate a uniform electric field; the tested unit is used for providing a standard excitation signal through a standard source matched with the to-be-tested sensor, simulating an input condition of the to-be-tested sensor under an actual working condition and collecting output data of the to-be-tested sensor; and the control unit is used for setting test parameters, generating a control instruction according to the test parameters and generating a test result according to the output data. According to the device and the method, by simulating a strong magnetic field and a strong electric field environment and combining application of various measured parameters and an automatic control system, the reliability evaluation requirement of the sensor under the actual working condition is fully met.

The invention discloses an LLC-DCDC fault protection method and device based on resonance current and pulse integration. The method comprises the following steps that an alternating current signal on an LLC converter resonance inductor is collected in real time through a resonance inductor current sampling circuit; inputting the current signal into a hardware comparator module, comparing the current signal with a preset current threshold value, and outputting a pulse signal; inputting the pulse signal into a pulse integral module for integral processing, and outputting an integral voltage signal; the CPU control unit receives a pulse signal output by the hardware comparator and an integral voltage signal output by the integral module in real time, and judges whether a fault occurs or not according to preset logic; and if the fault is judged, the driving signal of the primary inverter bridge of the LLC converter is cut off through the driving cut-off module.

A marine AC generator system includes a marine generator driven by an internal combustion engine and configured to generate an AC current and a rectifier configured to rectify the AC current to provide a DC current. At least one battery is configured to receive and be charged by the DC current. A battery powered inverter is configured to be powered by the at least one battery and to generate a variable current output frequency such that an AC electrical power is provided to a load when the marine generator is not running.

A control method of a dual active bridge converter, an energy storage device and a readable storage medium, the control method comprising: determining a feedforward value of an external phase shift angle and an adjustment value of the external phase shift angle according to an electrical parameter of the dual active bridge converter; and controlling the energy conversion of the dual-active bridge converter according to the feed-forward value of the external phase shift angle and the adjustment value of the external phase shift angle. When the dual active bridge converter performs energy conversion according to the generated driving signal, the feed-forward value of the external phase shift angle can be actively adjusted based on the target alternating current so as to adjust the given value of the external phase shift angle, so that the given value of the external phase shift angle can change along with the change of the target power supply current; therefore, the generated driving signal can actively adjust the output actual alternating current in time, and the purpose of reducing the output current or voltage waveform oscillation of the dual-active bridge converter is achieved.

The invention provides a network construction control method and system for a static var generator without a super capacitor, and the method comprises the steps: obtaining a variable needed by the control of the static var generator, comprise a three-phase bridge arm voltage measurement value, a three-phase bridge arm voltage instruction value, a reactive power instruction value, an alternating voltage amplitude instruction value, an output reactive power measurement value, an output alternating current measurement value, an alternating voltage amplitude measurement value of a common coupling point, a direct-axis voltage measurement value and a quadrature-axis voltage measurement value; obtaining a three-phase modulation voltage through a voltage loop and an alternating current loop according to variables required by control and based on direct current voltage-frequency-phase control and reactive power-voltage droop control; and obtaining a switch tube control signal according to the three-phase modulation voltage, and completing network construction control of the static var generator according to the switch tube control signal. According to the invention, the stability of the DC voltage of the static var generator can be ensured without adding a super capacitor, and active support is provided for an AC side power grid.

The invention discloses a current sensing measurement device and method, a storage medium and electronic equipment, and the device comprises an AC detection module which is used for sensing an AC current and outputting an AC current analog signal; the direct-current compensation module is used for acquiring magnetic induction intensity generated by a direct-current component of the detected current and outputting a differential voltage analog signal; the compensation module is used for outputting compensation current which is equal to the direct-current component in size but opposite to the direct-current component in direction based on the compensation control signal output by the signal processing module so as to offset direct-current magnetic flux generated by the direct-current component; and the signal processing module is used for calculating a direct current component, a compensation current and an alternating current based on the alternating current analog signal and the differential voltage analog signal, and outputting the compensation control signal based on the direct current component. According to the invention, direct current interference can be effectively suppressed, air gap nonlinear errors can be compensated, influences caused by environmental changes and equipment aging can be adapted, high precision and high reliability of a measurement system can be maintained during long-term operation, and the requirement of high-precision field calibration can be met.

A modular multilevel power converter includes: a capacitor voltage adjuster that calculates an active current component command to make an average voltage of capacitors match a command value; an active power detector that receives an AC current signal and an AC voltage signal and calculates an active power; an active power adjuster that calculates a DC current command value to make the active power match a command value; a first active power command suppressor that suppresses an absolute value of an active power command value; and a second active power command suppressor that adjusts an absolute value of an active power command value.

The invention provides a new energy automobile, a battery alternating current heating system and a heating control method. The battery alternating current heating system comprises a power battery unit, a three-phase bridge arm unit, a bus capacitor, a first switch and a motor. The bus capacitor is connected in parallel with the three-phase bridge arm unit, one parallel end is connected to the anode of the power battery unit through the first switch, and the other end is connected to the cathode of the power battery unit; the positive electrodes of the power battery units are further connected to corresponding phase windings in the motor through corresponding second switches, and an inductance adjusting unit is arranged on at least one phase winding branch and comprises an inductor and a third switch which are connected in parallel. In other words, the inductor and the switch assembly are additionally arranged in the battery alternating current heating system, the battery end alternating current effective value and the NVH performance in the heating process are improved, and the problems existing in an existing electric automobile in the low-temperature environment are solved.

The invention discloses a test platform for distribution network primary and secondary fusion complete switch equipment and a test method thereof, and the test platform consists of a control cabinet, a power output cabinet, a primary test cabinet, a secondary test cabinet, a voltage-boosting and current-boosting cabinet and a test management system. The test management system comprises a complete test system, a primary test system and a secondary test system, and the test management system and the primary and secondary fusion complete equipment perform information interaction through a standard communication interface. According to the technical scheme, accuracy measurement of voltage, current, power, frequency and wave recording of complete equipment of a tested object is realized through an adjustable three-phase power supply. According to the technical scheme, the 10kV test voltage and the 800A alternating current can be applied at the same time, the implementation method of the network access detection test of the primary and secondary fusion complete switch equipment of the power distribution network can be solved, and a guarantee can be provided for safe operation of the power distribution network.

A series-type hybrid circuit breaker to provide protection against short circuit faults in DC or AC power circuits. A series-type hybrid circuit breaker (SHCB) forces a fault current into a high-frequency AC current with zero crossings and allows a mechanical circuit breaker to disconnect the faulty branch. The SHCB injects a transient counter voltage pulse via a pulse transformer into the main power loop upon detection of an overcurrent condition and forces the fault current to change its original direction and cross zero to a negative peak value. A generation power electronic circuit on the primary side of the transformer controls the discharge of a capacitor to generate the counter voltage pulse during the first phase of each switching cycle of the fault interruption process. The power electronic circuit then changes the polarity of the injected secondary voltage and forces the fault current to change direction and cross zero again.

A method for heating a battery pack of an electrified powertrain system having an electric motor includes determining a temperature of the battery pack. Responsive to the battery temperature being less than a predetermined threshold temperature, the method includes executing a self-heating mode of the battery pack. This includes injecting a high-frequency direct-axis alternating current voltage waveform that minimizes output torque and prevents rotation of a rotor of the electric motor. An AC current waveform is applied to the battery pack as a result of the voltage injection. A controller includes a temperature sensor configured for determining a temperature of the battery pack and a processor configured to perform the method. A motor vehicle includes the controller, an electrified powertrain system having the battery pack and an electric motor, and road wheels connected to and powered by electric motor.

The invention discloses an electric energy meter intelligent load control method based on electricity utilization behavior analysis, and relates to the technical field of electric power metering, and the method comprises the steps: collecting current waveform data and power parameters through an electric energy meter metering chip; according to the current waveform data, zero crossing point moment information of the alternating current is determined; generating a load control instruction according to a comparison result of the power parameter and a preset power threshold value; and determining a switch control moment according to the zero-crossing moment information and the action delay parameter of the built-in switch, and controlling the built-in switch to execute on-off operation at the zero-crossing moment according to the load control instruction and the switch control moment. By capturing the current zero crossing point moment, arc-free on-off control of the built-in switch is achieved, energy loss and electromagnetic interference in the switch action process are reduced, and the service life of the switch is prolonged; and meanwhile, a periodic detection mechanism is adopted, power supply is automatically recovered on the premise of ensuring power utilization safety, and the power supply reliability and the user experience are improved.

The invention discloses a high-power alternating-current impedance excitation circuit, a control method thereof and an electrolysis test system, and belongs to the technical field of power supplies and power electronics, the circuit is used as an alternating-current power supply in a high-capacity electrolysis test power supply, and the circuit is controlled by a controller to output an alternating-current signal so as to carry out an impedance test on an electrolytic bath. Compared with a full-bridge circuit, the alternating-current impedance excitation circuit adopts the multi-level converter, so that the output current harmonic content is low, the electrolysis efficiency is improved, the equipment loss is reduced, the economical efficiency of an electrolysis system is improved, stable operation of an electrolytic bath is ensured, and electrolysis interruption or faults caused by voltage fluctuation are reduced.

The invention relates to a battery internal resistance testing method and circuit, and the method comprises the steps: sequentially applying alternating current excitation signals of a plurality of frequency points distributed in a specified frequency scanning range to a tested battery in a frequency scanning mode, and enabling the amplitude of the alternating current excitation signals to be smaller than or equal to a preset amplitude, the distribution of the plurality of frequency points is related to an equivalent circuit model adopted by the tested battery; acquiring a voltage response signal generated by the tested battery under the action of the alternating current excitation signal, and acquiring an alternating current signal flowing through the tested battery; acquiring complex impedance data corresponding to each frequency point in the plurality of frequency points based on the voltage response signal and the alternating current signal; and performing parameter fitting on the complex impedance data of the plurality of frequency points and the equivalent circuit model to obtain parameter values related to the internal resistance of the battery, and generating a battery internal resistance test result. The scheme provided by the invention can improve the test efficiency and test precision of the internal resistance of the battery.

The invention discloses a coal mine tunnel shield excavation-following multi-frequency alternating current parallel advanced detection method and system, and the method comprises the steps: arranging a three-direction data observation system in a tunnel excavation direction; collecting a three-direction potential difference amplitude value and a three-direction potential difference phase value for the arranged three-direction data observation system by adopting a multi-frequency pseudo-random galvanic couple source emission mode; the obtained three-direction potential difference amplitude value and the potential difference phase value are sent to professional software based on a Cole-Cole model for inversion, and a three-dimensional apparent resistivity image and a three-dimensional apparent charging rate image are obtained; according to the method, the problems that a traditional advanced detection method is insufficient in space positioning of a geologic body and detection is carried out while excavation under the tunnel shield condition are solved, and technical support is provided for tunnel shield excavation-while-excavation water disaster detection.

The invention, which belongs to the technical field of the energy storage converter, discloses an electrical parameter sensing-based service life monitoring system for a capacitor of a network-forming type energy storage converter, comprising the following steps of: synchronously acquiring a direct-current voltage signal and a three-phase alternating-current signal of a direct-current bus capacitor through an electrical parameter acquisition module to form a multi-dimensional feature vector; a state observer built in the ESR estimation module is used for analyzing the signal, a target capacitor ESR value is obtained, and a capacitor core temperature value is obtained through back-stepping through an electric-thermal coupling field analysis model of a core temperature back-stepping module in combination with preset capacitor surface temperature data; based on the ESR value and the capacitor core temperature value, a life prediction module calculates the residual life and health degree index of the capacitor; and the power scheduling module executes capacitor health degree-power output joint scheduling according to the health degree index, adjusts the power fluctuation range of the converter, and feeds back real-time working condition data to the electrical parameter acquisition module, thereby realizing accurate monitoring of the capacitor state and intelligent scheduling of the converter power.

The invention relates to a contact resistance and state detection method for an electromagnetic switch device of a railway vehicle, and the method comprises the steps: injecting an AC signal into a to-be-detected contact of the electromagnetic switch device, and then collecting an AC voltage signal of the to-be-detected contact; calculating a first resistance value of the contact to be measured according to the acquired alternating current signal and the alternating voltage signal; and further comparing the resistance value obtained by detecting the contact to be detected with a pre-configured resistance scale value, and judging whether the contact to be detected is in a good state or not according to a comparison result. On-line detection of the contact resistance of the electromagnetic switch device can be realized, and on the basis, judgment of the electricity storage state can be realized, so that the working safety and reliability of equipment are improved.

The invention provides a new energy automobile, a battery alternating current heating system and a heating control method. The battery alternating current heating system comprises a power battery unit, a three-phase bridge arm unit, a bus capacitor, a first switch, a second switch, an inductance adjusting unit and a motor. The bus capacitor is connected in parallel with the three-phase bridge arm unit, one parallel end is connected to the positive electrode of the power battery unit through the first switch, and the other end is connected to the negative electrode of the power battery unit; the positive electrode of the power battery unit is further connected to the neutral point of the motor through a second switch and an inductance adjusting unit in sequence, and the inductance adjusting unit comprises an inductor and a third switch which are connected in parallel. The effective value of the alternating current at the battery end and the NVH performance in the heating process are improved, and the problems existing in an existing electric automobile in the low-temperature environment are solved.

Secondary sub-circuit (6) for the electrical power supply of an electrical energy storage unit (2), this sub-circuit (6) being capable of contactless exchange by inductive coupling of electrical energy with a primary sub-circuit (4) capable of being connected to a voltage network (5), and this sub-circuit (6) also being capable of being connected to an electrical energy storage unit (2), the secondary sub-circuit (6) comprising: - a secondary inductive cell (20) for contactless exchange by inductive coupling of electrical energy with the primary sub-circuit (4), - an inverter / rectifier (23) capable of performing an impedance adaptation of the impedance on the alternating input of this inverter / rectifier (23), independently of the impedance of the electrical energy storage unit (2),this inverter / rectifier (23) comprising at least two switching arms (24) namely: - a first switching arm switching at the frequency of the electrical energy induced in the secondary inductive cell (20) and, - a second switching arm (24) switching at a frequency higher than that of said electrical energy and with a duty cycle modulated according to the alternating current flowing in the secondary inductive cell (20) and the voltage on the alternating input of this inverter / rectifier (23), the second switching arm comprising two switching cells (12) arranged on either side of a midpoint (25) of this second switching arm, at least one of these switching cells (12) comprising at least two controllable electronic switches (29) arranged in parallel. Abstract figure: Fig.1,

A magnetic inductive resonance charging circuit includes a resonant network having an inductive secondary coil that converts a magnetic field received from an inductive primary coil into an alternating current (AC) signal and a synchronous rectifier that rectifies the AC signal to generate a direct current (DC) signal for application to a load. The synchronous rectifier includes a variety of configurations for shunting the AC waveform of an AC current source in the event of a fault. For example, a rectifier controller may hold a pair of normally open switches of the rectifier off and a pair of normally closed switches of the rectifier on to shunt the AC current source when an over-voltage, over-current fault condition or an over-temperature fault condition is detected. Configurations are provided for grounding the capacitive electromagnetic interference produced in the chassis of an electric vehicle when the resonant network is unbalanced.

The invention discloses a switch cabinet temperature rise prediction method and device, equipment and a storage medium, and relates to the field of power transmission and transformation devices and equipment.The method comprises the steps that first heating power meeting a preset heating stable condition is determined based on the comprehensive heat dissipation coefficient of a target switch cabinet conductor, and the relation between temperature rise and power-on time is obtained in combination with a preset heat balance equation; constructing a first temperature rise prediction model; second heating power corresponding to the alternating current is determined, a temperature rise and current relation is established according to the first heating power, the second heating power and the heat dissipation coefficient, and a second model is constructed; circuit resistance is calculated through conductor resistance and contact resistance, the relation between temperature rise and contact resistance is determined by combining the two models, and a third model is constructed. And determining the three models as target temperature rise prediction models, establishing a target three-dimensional model based on the switch cabinet structure for verification, and performing temperature rise prediction after verification is passed. Therefore, the temperature rise risk of the switch cabinet can be accurately predicted.

The invention discloses a method for constructing a correlation mathematical model of time-phased overcurrent capability and electric-thermal limit parameters of a power device of a high-voltage direct-hanging network-constructing energy storage system. Based on the short-time overload capacity requirement of the energy storage system, obtaining a selection range of an alternating current operation point; the alternating current operation point is selected in the range; calculating current flowing through a power device in a converter valve bridge arm of a direct-hanging converter of the energy storage system; calculating the junction temperature of the power device under the alternating current operation point; checking whether the current flowing through the power device and the junction temperature meet an electric-thermal limit constraint condition or not; and classifying the alternating current operation points according to the short-time overload capacity requirement, and further obtaining the active and reactive current safe operation range of the high-voltage direct-hanging grid-constructing type energy storage system.

The invention relates to a thermodynamic design method for distributed overhead ground wire alternating current ice melting, and belongs to the technical field of power transmission line ice melting. The method aims at solving the problems that an existing ice melting technology is high in power consumption, low in efficiency, difficult in equipment movement and lack of fine design of a current regulation and control strategy. The core of the technical scheme is that a thermal equivalent theoretical model and an electric heat flow coupling simulation model of the overhead ground wire are established, key thresholds such as wire protection current, critical ice melting current and maximum allowable current are determined through calculation, and an effective value of alternating current injected into the ground wire is flexibly adjusted by using a reactive power compensation device. According to the method, segmented ice melting according to needs can be achieved, energy consumption is remarkably reduced, the ice melting efficiency and safety are improved, and the needed device is small in size, convenient to move and deploy and suitable for various complex icing working conditions.

A motor vehicle includes an AC (alternating current) electric motor having a stator with a plurality of stator windings, a rechargeable source of stored electrical energy, and an inverter coupled to the rechargeable source of stored electrical energy and to the AC electric motor. The system also includes one or more controllers collectively programmed to switch the inverter to provide alternating current propulsive energy from the rechargeable source of stored electrical energy to the plurality of stator windings and, using at least one of the stator windings as a boost inductor, switch the inverter to step up a voltage at a charging input coupled to the inverter to charge the rechargeable source of stored electrical energy.

The embodiment of the invention provides a power supply distribution method, a power supply distribution circuit, a storage medium and electronic equipment, and the power supply distribution method comprises the steps: carrying out the rectification conversion of at least two AC power supplies through at least two rectification units, so as to output a first DC power supply, each rectification unit comprises an automatic conversion unit and a power factor correction unit, and the number of the rectification units is consistent with that of the alternating current; receiving the first direct-current power supply through at least one step-down conversion unit, and adjusting the voltage corresponding to the first direct-current power supply to generate a second direct-current power supply; the second direct-current power supply is distributed to a plurality of power supply rails through a power supply redistribution module, and the power supply rails are used for supplying power to a target processor.

The invention provides a neutral-point potential control method and system for a three-level converter, and relates to the technical field of intelligent control, positive bus voltage and negative bus voltage are sampled, a voltage deviation value is calculated, an additional control quantity is generated according to the voltage deviation value and a symbol of alternating current, and the additional control quantity is obtained through a symbol function and proportional control processing; performing amplitude limiting processing on the additional control quantity to obtain an amplitude-limited additional control quantity; superposing the amplitude-limited additional control quantity on the positive modulation wave, negating the amplitude-limited additional control quantity, and superposing the negated amplitude-limited additional control quantity on the negative modulation wave to obtain a final positive modulation wave and a final negative modulation wave; comparing the final positive modulation wave and the final negative modulation wave with a carrier wave, and generating a driving signal of the power device; and the on-off of the switching device is controlled according to the driving signal, so that a corresponding level is output to realize neutral-point potential balance. According to the invention, neutral-point voltage low-frequency fluctuation and direct-current offset suppression can be realized at the same time.

An improved charging device with Smart IOT connected features is disclosed. The charging device provides AC current to various external devices, including electric vehicles and household appliances. The device includes a portable housing assembly with at least one charging port and an integrated smart battery charger that monitors voltage and current levels. An inverter converts stored DC power into AC power. The LCD touchscreen displays real-time charging status and supports touch activation commands from a mobile communication device for remote operation.