1694 results about "Ac current" patented technology

A household vacuum sealer contains: a base, a lid, and a hot-melt sealing element. The base includes a receiving chamber for accommodating a control circuit and a vacuum pump. The base also includes a vacuuming chamber and an accommodation chamber. The hot-melt sealing element includes a holder, a mica slice, a laminated heating layer, the insulated composite layer, and a protective cap. The insulated composite layer includes multiple insulated tape layers. The laminated heating layer includes a high-temperature resistance tapes made of polyimide, a metal resistance tape, two electrical connection films, and two alternating current (AC) electrodes. The mica slice is parallelly fixed on a top of the holder. The laminated heating layer includes the two electrical connections. Furthermore, the protective cap is covered on the insulated composite layer and includes a hollowly elongated zone.

According to the battery internal resistance measurement method and device, high-frequency oscillation signals are generated based on the temperature and current state of a target battery measured in real time and injected to the two ends of the target battery, and the influence of the temperature and current state on the battery internal resistance measurement result is fully considered; performing multi-band analysis on the AC voltage signals at the two ends of the target battery and the AC current signal in the target battery to obtain response characteristics of the target battery under different frequencies; and after the internal resistance value of the target battery in the preset frequency band range is calculated from the corresponding response characteristics by using a ratio method, the measured internal resistance value is corrected according to the real-time temperature and the current state, and finally the internal resistance measurement value of the target battery is obtained. The internal resistance measurement deviation possibly occurring in different environments can be effectively eliminated, and the problem that internal resistance measurement is inaccurate due to the fact that it is difficult to distinguish the internal electrochemical impedance and temperature of the battery and the influence of the current state on the battery performance is solved.

The invention provides a battery heating system of a vehicle, a control method and the vehicle. The system comprises a multi-phase inverter, a multi-phase winding, an energy storage device and a controller. Wherein a bus of the multi-phase inverter is correspondingly connected to a bus of a vehicle battery, one end of the multi-phase winding is correspondingly connected to a bridge arm of the multi-phase inverter, a neutral point of the multi-phase winding is connected to one of the buses of the battery, the energy storage device is connected to the battery, and the controller is connected to the multi-phase inverter; the controller is configured to determine a direct current duty ratio signal and an alternating current duty ratio signal according to the real-time heating requirement of the battery, and control the action of a bridge arm of the multi-phase inverter based on the direct current duty ratio signal and the alternating current duty ratio signal. And heating the battery by using the target alternating current corresponding to the real-time heating requirement of the battery formed at the neutral point of the multi-phase winding. The DC duty ratio signal and the AC duty ratio signal jointly control the action of the multi-phase inverter, so that the battery can be heated through the modulatable duty ratio signal.

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.

The invention relates to the field of power system protection and control, and discloses a flexible direct current power transmission system receiving end voltage control method, device and equipment. A receiving-end converter station of the flexible direct-current power transmission system collects alternating-current bus voltage, active current and reactive current before and after a fault, and calculates equivalent complex impedance and a potential vector after the fault of a receiving-end power grid; calculating and comparing the maximum alternating current phase angle of the receiving end converter station for avoiding the direct current transient overvoltage of the flexible direct current power transmission system with the alternating current phase angle of the receiving end converter station required for maximizing the voltage of the receiving end grid-connected point of the flexible direct current power transmission system; calculating the maximum feasible value of the grid-connected point voltage of the receiving end of the flexible direct-current power transmission system on the premise of avoiding the direct-current transient overvoltage; and calculating and adjusting active and reactive current reference values of the receiving end converter station of the flexible direct-current power transmission system, and controlling the voltage of the receiving end grid-connected point of the flexible direct-current power transmission system to the maximum feasible value under the power grid fault. According to the method, active and reactive currents of the receiving end converter station of the flexible direct-current power transmission system are coordinated, so that the maximum voltage rise of the receiving end grid-connected point under the direct-current voltage safety condition of the flexible direct-current power transmission under the power grid fault is quantified and realized.

The invention provides a control method of a power conversion circuit, power conversion equipment and a power supply system. The control method can obtain a target inner phase shift duty ratio corresponding to the highest voltage matching degree according to the real-time direct-current voltage and the real-time alternating-current voltage, and obtain a reference outer phase shift duty ratio according to the real-time direct-current voltage, the real-time alternating-current voltage, the target inner phase shift duty ratio, preset target alternating-current power and power transmission constraint conditions. Adjusting a reference outer phase shift duty ratio according to the real-time alternating current and a preset target alternating current to obtain a target outer phase shift duty ratio, and obtaining a target switching frequency according to the real-time direct current voltage, the real-time alternating current voltage, the target inner phase shift duty ratio, the reference outer phase shift duty ratio, the target alternating current power and a switching frequency constraint condition, and controlling power transmission of the power conversion circuit according to the target switching frequency, the target inner phase shift duty ratio and the target outer phase shift duty ratio. According to the method, the transmission efficiency of the power conversion circuit can be improved, and the current stress can be reduced.

The invention provides an energy storage lithium battery online lithium precipitation detection framework and method based on an impedance spectrum and a safety threshold value, relates to the field of energy storage battery safety state diagnosis and energy management, and solves potential safety hazards caused by lithium precipitation in the operation process of an energy storage power station. According to the method, the relaxation time distribution characteristic value of the battery impedance spectrum is obtained by identifying the shelving state of the energy storage battery after charging and applying alternating current excitation with specific frequency combination and combining high-speed sampling and impedance spectrum analysis technologies. According to the method, no additional reference electrode is needed, in-situ and online detection is achieved, and the influence of the charging process on impedance change is effectively avoided. Through multiple times of detection and comparison of characteristic value changes, normalization and differentiation are carried out, then comparison with a lithium precipitation safety threshold value is carried out, and if the threshold value is exceeded, lithium precipitation occurs. According to the method, a reliable lithium precipitation detection means is provided for safety diagnosis and state estimation of the energy storage power station, the charging strategy can be optimized, abnormal attenuation of the battery capacity is prevented, and the probability of occurrence of safety accidents is reduced.

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.

An electric valve / door, and a control apparatus and method thereof are provided. The electric valve / door includes a control apparatus. The control apparatus includes an alternating current (AC) asynchronous motor, a transmission device, and a valve driver. The valve driver is connected to the AC asynchronous motor. The AC asynchronous motor is connected to the valve / door through the transmission device. The valve driver is configured to collect information of a real-time torque of the AC asynchronous motor or the valve / door during operation, and take a set torque of the valve driver as an input and the real-time torque as a feedback to immediately correct an output torque of the valve driver or a limit value of the output torque by using a proportional-integral-derivative (PID) control algorithm, to meet requirements for response speed and control precision of each stage in opening and closing processes of the valve / door.

The invention relates to the technical field of power electronics, in particular to an energy storage converter high-voltage ride-through control method, which comprises the following steps: acquiring a direct-current voltage value of an energy storage side and an alternating-current voltage value of a power grid side; judging whether the AC voltage value reaches a preset threshold value or not; if yes, determining a target state according to a comparison relationship between the AC voltage value and the DC voltage value; acquiring a voltage sampling value and an alternating current sampling value; based on a PI feedback control algorithm and coordinate transformation, generating and outputting a modulation signal according to the voltage sampling value and the alternating current sampling value; and controlling the energy storage converter to operate according to the modulation signal. According to the energy storage converter high-voltage ride-through control method provided by the invention, high-voltage fault ride-through is realized under the condition that additional circuits such as a DC chopper are not added, and the production hardware cost and the control complexity can be reduced.

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.

The invention discloses a low-loss superconducting motor and a design method thereof, and belongs to the technical field of superconducting motors. A low-loss superconducting motor comprises a vacuum chamber, a stator assembly and a rotor assembly are arranged in the vacuum chamber, and a protective cover is arranged between the stator assembly and the rotor assembly. One of the stator assembly and the rotor assembly is provided with a constant conductor coil, the other one is provided with a superconductor coil, the superconductor coil applies direct current, and the constant conductor coil applies alternating current. Meanwhile, the invention discloses a design method based on the superconducting motor, the low-loss superconducting motor and the design method thereof are adopted, an air gap between the stator assembly and the rotor assembly is small, a high magnetic field is easy to achieve, Joule loss of a common conductor coil is reduced, an air or water cooling pipeline can be omitted, and temperature control is easy.

The present invention provides a method of inhibiting the growth of proliferating cells or viruses in living tissue, the method comprising: applying mid-level frequency AC current electromagnetic signals to the living tissue with a transducer comprising a magnetically conductive material passing through a conduction ring energized by an electrical signal to create the mid-level frequency AC current electromagnetic signals within the living tissue; wherein the mid-level frequency AC current electromagnetic signals have a frequency in the range of about 50 kHz to about 300 kHz and are produced with an AC voltage generator; and circulating fluid in the living tissue provide a secondary coil for the transmission of the mid-level frequency AC current electromagnetic signals.

The invention provides a broadband electric field sensor, an electric field sensor assembly and an electric field detection method.The broadband electric field sensor comprises a substrate, at least one dynamic induction electrode and at least one static induction electrode, the substrate comprises an entity area and a concave area, and the dynamic induction electrodes and the static induction electrodes are arranged at intervals; one part of the dynamic induction electrode is attached to the entity area, the other part of the dynamic induction electrode is located on the concave area, one part of the static induction electrode is attached to the entity area, the other part of the static induction electrode is located on the concave area, and the dynamic induction electrode obtains at least one direct current signal of a current electric field according to an excitation signal; the static induction electrode obtains at least one alternating current signal of the current electric field at least according to charges induced in the current electric field. The direct current signal and the alternating current signal can be obtained at the same time, good detection of a direct current electric field and an alternating current electric field is achieved, the sensitive degree of electric field detection is improved, and the detection frequency band of the electric field sensor is widened.

The invention relates to the field of photovoltaic power generation, discloses a photovoltaic power station AGC instruction distribution method and device, an AGC system and a storage medium, and aims to improve AGC instruction distribution accuracy. The method comprises the following steps: in response to a received photovoltaic power station AGC instruction, determining the corresponding estimated maximum power generation capacity of each inverter in the photovoltaic power station at the current moment through a plurality of preset power generation capacity evaluation models; obtaining reactive power and alternating-current line voltage of each inverter in the photovoltaic power station at the current moment; based on the reactive power, the AC line voltage, the maximum AC current threshold, the maximum apparent power threshold and the corresponding estimated maximum power generation capacity of each inverter at the current moment, determining the target maximum power generation capacity corresponding to each inverter at the current moment; and performing power distribution based on the AGC instruction of the photovoltaic power station, the minimum adjustable power threshold value corresponding to each inverter and the target maximum power generation capacity corresponding to each inverter at the current moment to obtain a power instruction distributed to each inverter at the current moment.

The invention discloses a trapezoidal wave operation method of a T-type direct-current transformer. The method comprises the following steps: step 1, designing waveform constraint conditions of a multi-phase T-type direct-current transformer; 2, designing an alternating current waveform of the three-phase T-type direct current transformer; and 3, designing the optimal alternating current waveform of the three-phase T-type direct current transformer. The problems of low voltage and current utilization rate and high current stress caused by the fact that the T-type direct-current transformer adopts a sine operation mode are solved, the power capacity of the T-type direct-current transformer is remarkably improved, and the T-type direct-current transformer topology can be applied to high-voltage and high-capacity occasions. On the premise that the topological structure and the number of devices of the T-type direct-current transformer are not changed, the transmission power capacity of the T-type direct-current transformer is remarkably improved, the power loss of the devices is reduced, and the T-type direct-current transformer has great significance in topological application of an existing T-type direct-current transformer.

An apparatus for determining the health of a battery including a plurality N of series-connected cells. The apparatus includes an AC signal source operable to cause an AC current to flow through one or more cells of the plurality of series-connected cells, a current measurement unit operable to measure the AC current, a voltage measurement unit operable to measure an AC voltage induced across the one or more cells by the AC current, and a health determination unit operable to determine a measurement of the health of the battery based on the measured AC current and the measured AC voltage.

A control architecture that overcomes limitations of conventional ac-dc converters and enables bidirectional active and reactive power processing is provided. In one implementation, for example, this may be achieved through the use of unrectified sensed ac signals in the generation of the control commands for the converter. This control architecture, in this example implementation, eliminates or at least reduces zero crossing distortions in the ac current of the converter even with relatively low bandwidth controllers. The concept can be applied to different power stage topologies.

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 an inertia and damping coefficient detection method, system and device of power electronic equipment, and relates to the technical field of power electronics, and the method comprises the steps: obtaining the AC voltage and AC current of to-be-detected power electronic equipment in real time; determining a frequency and a frequency change rate based on the AC voltage; determining active power based on the AC voltage and the AC current; generating a disturbance signal based on the frequency, the active power, the AC voltage or the AC current; when the disturbance signal is 0, no processing is carried out; when the disturbance signal is 1, obtaining a frequency vector, a frequency change rate vector and an active power vector during disturbance based on the frequency, the frequency change rate and the active power; and based on the frequency vector, the frequency change rate vector and the active power vector, determining an inertia coefficient and a damping coefficient of the to-be-tested power electronic equipment. The inertia and damping coefficient of the power electronic equipment can be accurately detected on line in real time, so that the dynamic behavior of the power electronic equipment can be reflected more comprehensively.

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 an energy management system and an energy management method of an electromagnetic vibration energy harvesting device. The energy management system comprises an AC / DC selection unit, a three-phase rectification circuit, a filter circuit, a charging management unit, an anti-backflow circuit and a system power supply module. Wherein the alternating current and direct current selection unit selectively conducts an alternating current path or a direct current path based on the time-varying characteristic of real-time current output by the electromagnetic vibration energy harvesting device; the three-phase rectifying circuit is used for rectifying alternating current in the alternating current path into direct current; the filter circuit is used for filtering the direct current passing through the direct current path; the charging management unit performs charging management on the energy storage device based on the current input by the alternating current path or the direct current path; the anti-backflow circuit is used for preventing current backflow; the system power supply module is used for supplying power to the AC-DC selection unit and the charging management unit. According to the invention, flexible and efficient energy management can be realized for the energy output characteristics of the electromagnetic vibration energy harvesting device.

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.

The invention belongs to the technical field of power electronics, and relates to a SiC device three-level six-switch split topological rectifier control method and system. A q-axis instruction current is generated according to a power grid voltage phase angle and a square wave voltage phase angle obtained after conversion and phase locking of the three-phase power grid voltage and the square wave voltage, and a d-axis instruction current generated according to given and actual DC bus voltages; generating a three-phase voltage modulation signal according to the instruction current, the power grid voltage phase angle, and the power grid voltage and the power grid current under the two-phase rotating coordinate system, converting the three-phase voltage modulation signal into a voltage modulation signal under a two-phase static coordinate system, and generating a large sector number according to the converted voltage modulation signal; generating a three-phase modulation wave according to the translated voltage modulation signal under the two-phase static coordinate system, and generating a driving signal according to a comparison result of the three-phase modulation wave and a set carrier, and NAND logic and a large sector number of the comparison result. The alternating current zero-crossing distortion is effectively reduced, the sine degree of the current waveform is high, and the current quality is high.