14792results about "Ac-dc conversion" patented technology

A portable fan includes an airflow portion and a handheld portion. The airflow portion includes rotation air blades and a drive portion that is driveably connected to the rotation air blades. The drive portion is a three-phase motor that is configured to drive the rotation air blades to rotate to generate an airflow. The handheld portion is connected to the airflow portion. A power supply assembly is arranged inside the handheld portion; and the power supply assembly is electrically connected to and supply power to the three-phase motor.

A handheld fan includes an air supply portion and a handheld portion. The handheld portion includes a first outer shell and a battery module arranged in the first outer shell. The battery module includes a battery housing, and a first storage battery and a second storage battery which are arranged in the battery housing. The first storage battery and the second storage battery are connected in series through an electrical connector. The first storage battery and the second storage battery are arranged in a battery housing. The first storage battery and the second storage battery are connected in series or in parallel through an electric connector, which increases the battery capacity of the handheld fan, so that when a user uses the handheld fan, the battery life can be longer, bringing a better user experience.

The invention discloses a sequence impedance remodeling-based grid-forming converter system resonance suppression method and system, and the method comprises the steps: obtaining linearized grid-side voltage, grid-side current and converter-side current small signals based on the active and reactive power control strategy of a grid-forming converter and the voltage and current double-closed-loop control principle; establishing a sequence impedance model of the output impedance of the network construction type converter system based on the virtual synchronous generator; based on the sequence impedance model, combining a passivity theory to determine a system stability condition; in combination with the condition of system stability, an active damping feedback loop is introduced in a voltage control link of the grid-forming converter, equivalent output impedance of converter resonance control is remodeled, a non-passive area for outputting positive and negative sequence impedance is reduced, and grid-connected current harmonic resonance suppression of the grid-forming converter is realized. According to the method, a sequence impedance model is used for performing impedance remodeling of a grid-connected system for the first time, equivalent series virtual damping and a feedback control ring of an equivalent wave trap are specifically introduced into a converter system to perform sequence impedance waveform remodeling, and then the stability and robustness of the system are controlled.

The present invention provides an inverter control method, device, computer equipment and storage medium, belonging to the field of power electronics. The method comprises: determining a frequency control equation of the inverter under a grid-connected condition when the inverter is in a VSG control mode; determining a relationship between a virtual electromotive force of a virtual synchronous generator in a reactive state and an output voltage of the inverter; constructing a voltage-current double closed-loop control structure of the inverter under the VSG control mode, and determining a current reference value and a voltage reference value of the virtual synchronous generator under dq axes through the frequency control equation and the relationship; constructing a fuzzy control rule of a virtual damping coefficient and a virtual inertia according to the current reference value and the voltage reference value; and controlling the virtual damping coefficient and the virtual inertia through the fuzzy control rule, thereby improving the stability and performance of the inverter during the grid-connected process, reducing the harmonic disturbance of the power system, and helping to improve the adaptability and reliability of the entire photovoltaic power generation system.

The invention relates to the field of high-voltage direct-current power transmission, and aims to provide an MMC converter valve and method for realizing alternating-current and direct-current fault ride-through based on an energy consumption sub-module. On the basis of a topological structure of a conventional MMC converter valve, M energy consumption sub-modules which are sequentially connected in series and are the same in structure are arranged between a bridge arm inductor of each bridge arm and the midpoint of an upper bridge arm and the midpoint of a lower bridge arm, and each energy consumption sub-module comprises a main through-flow branch, an energy consumption branch and a bypass loop which are connected in parallel; in the main through-current branch, the half-controlled switching device T1 is reversely connected in parallel with a fly-wheel diode D1 of the half-controlled switching device T1, and then is reversely connected in series with the full-controlled switching device T2 and a reverse fly-wheel diode D2 of the full-controlled switching device T2; the energy consumption branch comprises an energy consumption resistor Rd, and the bypass branch comprises a bypass switch K. According to the invention, alternating current fault ride-through and direct current fault ride-through are integrated into the topology of the MMC converter valve, so that the integration level of the protection scheme is improved; voltage fluctuation during alternating-current fault ride-through can be effectively smoothed, and the stability during alternating-current fault ride-through is improved.

The invention discloses an inverter intelligent control method based on a self-adaptive algorithm, and relates to the technical field of inverter intelligent control, and the method comprises the steps: multi-source temperature collection and environment recognition, machine learning-based electric-thermal coupling prediction, self-adaptive inverter parameter optimization, and cooperative thermal management and fault diagnosis self-repairing. According to the high-temperature or low-temperature failure risk of the motor and the inverter under the extreme climate, temperature distribution and load information are obtained in real time, the temperature rise trend is predicted in advance, and the current, voltage and modulation strategy of the inverter are actively adjusted, so that safe derating or torque compensation is achieved; multi-sensor cross validation and observer fusion are carried out when sensors drift or devices are aged, stable operation and efficient energy utilization of the system are kept, and the drivability and the whole vehicle reliability in an extreme environment are remarkably improved; in the process, fault diagnosis and self-repairing can be further improved through online model updating, and the durability and economical efficiency of the electric drive system are improved.

The invention discloses a network construction type VSG output power decoupling method based on voltage signal composite feedforward, relates to the technical field of power electronic control, and provides a network construction type converter grid-connected system and a method for realizing converter output power decoupling through converter output voltage signal composite feedforward for network construction type VSG power synchronous control. Comprising a network construction type VSG power control module, a power grid parameter detection unit, a line impedance observer, a virtual impedance voltage drop feedforward loop and a voltage signal secondary feedforward loop. According to the composite feed-forward control strategy, virtual impedance and voltage amplitude and power angle compensation are combined, the coupling effect of active power and reactive power is remarkably weakened, efficient decoupling is achieved, and the method is suitable for a complex power grid environment.

The invention relates to the technical field of energy storage, in particular to an energy storage converter which comprises a shell, the shell is provided with a first containing cavity, a second containing cavity and a third containing cavity which are distributed in the first direction, the first containing cavity is provided with an inductor, a radiator and a first cooling fan, and the second containing cavity is provided with a high-voltage box, a power device and a heating electronic device; the third accommodating cavity is provided with a control board, an anti-interference board and a power board; a first partition plate and a second partition plate which are distributed in a spaced mode in the second direction are arranged between the first containing cavity and the second containing cavity, the first partition plate can support the high-voltage box, and the second partition plate can support the heating electronic device; along a second direction, the power device is arranged between the first partition plate and the second partition plate, and the second direction is perpendicular to the first direction; a first supporting plate is arranged between the second containing cavity and the third containing cavity and supports the control plate, the anti-interference plate and the power panel. The energy storage converter is high in space utilization rate, small in size and high in operation stability.

The disclosure provides a circuit modeling method for a dual-active-bridge-type micro-inverter. The method equates dual-active-bridge-type micro-inverter to a standard dual-active-bridge circuit by establishing an equivalent circuit model, thereby establishing a third-order large signal model and a third-order small signal model of the micro-inverter, so as to facilitate the solution of a circuit state variable and the analysis of the dynamic performance.

The invention relates to the technical field of hybrid inverters, and discloses a hybrid inverter supporting reactive compensation and a control method thereof, and the hybrid inverter comprises a DC input unit, a three-phase full-bridge inversion unit, a grid-connected switching unit, a signal acquisition unit and a digital control unit. The direct current input unit comprises a photovoltaic interface, a battery interface and a direct current bus and is used for converging photovoltaic and energy storage electric energy; the three-phase full-bridge inversion unit is composed of a power device and an LCL filter and converts direct current into alternating current. The grid-connected switching unit comprises a static switch and an isolation transformer and is used for controlling power grid connection; the signal acquisition unit detects voltage and current signals; and the digital control unit judges a grid-connected mode or an off-grid mode according to the signal, calculates a reactive current reference value and generates a PWM (Pulse Width Modulation) control signal so as to realize reactive compensation control in the grid-connected mode and the off-grid mode. According to the invention, reactive power compensation capability is provided in both grid-connected and off-grid operation modes, and stable operation of the inverter in various working conditions is ensured.

The invention discloses an SVG topological structure and a staged starting method. The SVG topological structure comprises a starting loop, an MMC voltage source type converter branch and a super capacitor energy storage branch. The starting loop comprises a first switch and a starting resistor and is used for pre-charging the MMC voltage source type converter branch in a starting stage; the MMC voltage source type converter branch comprises six bridge arms and is used for converting alternating-current electric energy transmitted by the starting loop into direct-current electric energy and controlling voltage, current and reactive power of the alternating-current electric energy; the super capacitor energy storage branch comprises an energy storage unit and a current limiting reactor and is used for providing power support for the system through charging and discharging. According to the SVG topological structure and the staged starting method provided by the invention, the cost can be greatly reduced while the function of a conventional phase modifier is realized, and the starting stability of the SVG is improved.

A method of balancing voltages on flying capacitors in a multilevel power converter is provided (along with an associated controller). The power converter includes one or more flying capacitors. Pairs of switches in the power converter are controlled by pulse width modulated (PWM) control signals. The different pairs of switches are controlled by PWM control signals having a phase / timing shift between them. To balance the voltage on the one or more flying capacitors, one set of pulses can be widened or narrowed while another set is widened or narrowed. To change their widths, one edge of each pulse is modulated, while the other edge is unchanged. More specifically, the leading edge of one set of pulses is modulated, while the trailing edge of the other set of pulses is modulated.

A system includes: an AC-DC converter; and a DC-DC converter, the DC-DC converter including: a first high voltage buck-boost converter having a secondary side connectable to a first high voltage battery; a second high voltage buck-boost converter having a secondary side connectable to a second high voltage battery; a first low voltage buck-boost converter having a secondary side connectable to a first low voltage battery; a second low voltage buck-boost converter having a secondary side connectable to a second low voltage battery; and one or more transformers having a primary side connected to the AC-DC converter and a secondary side connected to each of a primary side of the first high voltage buck-boost converter, a primary side of the second high voltage buck-boost converter, a primary side of the first low voltage buck-boost converter, and a primary side of the second low voltage buck-boost converter.

The invention relates to the technical field of PWM control, and discloses a high-precision PWM dead zone effect compensation method and system. The method comprises the following steps: carrying out differential sampling and signal conditioning on PWM output current to obtain a current sampling value; the driving signal is input into an FPGA state judgment module for state conversion analysis, and switch state information is obtained; performing dead zone characteristic quantity extraction based on the current sampling value and the switch state information to obtain a dead zone effect influence factor; according to the dead zone effect influence factor, compensation coefficient calculation is carried out in a piecewise linear mode, a real-time compensation value and a predicted compensation value are obtained, the real-time compensation value and the predicted compensation value are used for compensating dead zone position voltage drop in a PWM output voltage waveform, the real-time compensation value is used for current period compensation, and the predicted compensation value is used for next period compensation presetting. And high-precision PWM dead zone effect compensation is realized. According to the method, accurate calculation and dynamic prediction of the compensation value are realized, the compensation adaptability is improved, and finer compensation control is realized.

The embodiment of the invention discloses a midpoint potential control method based on a diode clamping type three-level grid-connected inverter and a related device. The method comprises the following steps: generating an initial three-phase modulation wave through a current loop closed-loop control method according to a collected three-phase current value and a three-phase voltage value of a power grid side of the diode-clamped three-level grid-connected inverter; according to an initial modulation waveform generated by the initial three-phase modulation wave, a three-phase current value and an acquired voltage value of a voltage dividing capacitor at the direct current side of the diode clamping type three-level grid-connected inverter, calculating a zero-sequence component required by neutral-point potential balance; superposing a zero-sequence component required by neutral-point potential balance with the initial modulation waveform to obtain a final modulation wave; and generating a driving signal matched with each phase of bridge arm in the diode clamping type three-level grid-connected inverter according to the final modulation wave. By adopting the invention, the neutral-point voltage can be balanced, the distortion of the output waveform at the alternating current side is reduced, the voltage stress of the device is reduced, and the service life of the power device is prolonged.

Provided in the present invention is a transformerless unified power quality conditioner, comprising a three-phase conditioner substructure, wherein each phase of the conditioner substructure can comprise an ANPC three-level converter and an output half-bridge module connected to the ANPC three-level converter. Also provided are a corresponding modulation method and system and a corresponding control method and system. Compared with existing voltage regulation apparatuses, the transformerless unified power quality conditioner and the modulation method and control method therefor provided in the present invention do not include a power-frequency transformer in the topology, but use a three-level converter to expand ports to realize voltage regulation, thus having the advantages of lower costs, smaller size, smaller footprint, lower loss, etc.

The embodiment of the invention provides a grid-connected inverter control mode switching method and device, equipment, a medium and a product, and is applied to the technical field of electrical control. The method comprises the following steps: acquiring a control mode switching signal of the grid-connected inverter, and determining a switching direction of a control mode based on the switching signal; when the switching direction indicates that the current control mode is switched from the GFL mode to the GFM mode, setting an initial value of an integrator of a power synchronization loop of the GFM mode as a phase angle value of a phase-locked loop corresponding to the GFL mode; switching the control mode from the GFL mode to the GFM mode based on a first preset path and a step-by-step switching mode; when the switching direction indicates that the current control mode is switched from the GFM mode to the GFL mode, acquiring a power steady-state output value of the GFM mode, and setting a power reference value of the GFL mode as the power steady-state output value; and switching the control mode from the GFM mode to the GFL mode based on the second preset path and the step-by-step switching mode. The technical effect of improving the control mode switching fluency is achieved.

Disclosed are a method and an apparatus of digital feedback based adaptive delay time control for a high efficiency active rectifier. According to the present invention, provided is an apparatus for digital feedback based adaptive delay time control, which adaptively compensates a driving delay of a switch by controlling a time of a delay circuit through a digital feedback-based compensation technique, and operate the switch at an appropriate timing in spite of changes in operation environments such as an input voltage and a load to increase the efficiency of an AC-DC rectifier.

The invention discloses a hybrid modulation strategy for neutral-point voltage balance control and common-mode voltage suppression of a three-level inverter, and belongs to the technical field of power electronics. In order to solve the problems that the neutral-point voltage of a three-level inverter is unbalanced and the common-mode voltage is large under traditional modulation, the invention provides a novel modulation strategy formed by mixing virtual space vector modulation and intermittent modulation, and according to virtual space vector modulation, space vectors with small common-mode voltage are selected to construct virtual small vectors and middle vectors; adjusting the midpoint current through the midpoint voltage control parameter; dPWMA capable of suppressing common-mode voltage is selected for intermittent modulation. According to the hybrid modulation strategy, common-mode voltage suppression can be kept, when the neutral-point voltage is balanced, DPWMA is selected to reduce switching loss, and when the neutral-point voltage is unbalanced, a modulation method which is more effective for recovering balance of the neutral-point voltage is selected to achieve the purpose of faster realization of neutral-point voltage balance.

The invention discloses a method for diagnosing an IGBT open-circuit fault and a current sensor fault of a T-type three-level inverter, belongs to the technical field of inverter fault diagnosis, and is used for solving the problems of diagnosis and positioning when a three-level T-type inverter IGBT switch tube and a sensor have faults. Comprising the following steps: classifying and marking and numbering fault types of an open-circuit fault of a T-type three-level inverter IGBT and a fault of a current sensor; fault samples are collected and divided into a training set and a test set according to the proportion of 7: 3; a TCN-LSTM-SelfAction fault diagnosis model is constructed, and model training is carried out by using the training set; the trained model is used for evaluating the accuracy of fault type diagnosis of the training set and the test set. According to the diagnosis method, the fault types and the fault positions of the IGBT open-circuit fault and the current sensor fault can be diagnosed at the same time, the TCN and the LSTM are selected to be combined, local information and global relation of fault features can be captured at the same time, and meanwhile, the performance of a model is improved by combining a self-attention mechanism in the LSTM, and the accuracy is improved.

A power converter having a power conversion circuit, a filter provided and a control device configured to control an output voltage of the power conversion circuit to a power system. The control device includes: a voltage amplitude command calculation unit configured to calculate an amplitude command value for the output voltage; a frequency command calculation unit configured to calculate a frequency command value for the output voltage; a current command calculation unit configured to calculate a first current command value for the output current; and a voltage command calculation unit configured to generate a command value for the output voltage. The current command calculation unit, responsive to a magnitude of the first current command value exceeding an upper limit value, calculates a second current command value as the current command value, by restricting the magnitude of the first current command value to the upper limit value.

Embodiments include an electric vehicle having a charging port configured to receive an alternating current (AC) power, a direct current (DC) battery, and a bidirectional inverter configured to convert AC power to DC power and to convert DC power to AC power, the bidirectional inverter is selectively connected to the DC battery by propulsion switches. The electric vehicle also includes an AC motor connected to the bidirectional inverter and selectively connected to the charging port by a first charging switch, an isolated DC / DC converter motor selectively connected to the DC battery via a second charging switch and a third charging switch, and a processor configured to control the operation of the propulsion switches, the first charging switch, the second charging switch, and the third charging switch based on an operational mode of the electric vehicle.

The invention relates to the technical field of power supply control, in particular to a power supply control method and system of an X-ray generating device. According to the method, working state parameters of an X-ray tube are detected in real time, and corresponding voltage / current deviation correction is generated according to a preset voltage-current characteristic curve; dynamically adjusting the driving frequency of the high-frequency inverter based on the voltage / current deviation correction, and collecting the ripple characteristic quantity fed back by the output end of the power supply to form a closed-loop correction factor; carrying out coupling analysis on the closed-loop correction factor and the X-ray tube cathode emission current change rate; reconstructing a trigger time sequence graph of the power switch device according to the phase compensation instruction, and synchronously injecting thermodynamic parameters of a pipe body to carry out duty ratio secondary correction; and generating a multi-parameter cooperative control instruction by iteratively optimizing the matching relationship between the trigger time sequence map and the duty ratio correction value. The self-adaptive precise adjustment of the power supply system is realized, so that the X-ray tube can obtain optimized power supply under different working conditions.

The invention belongs to the field of driving circuits of gallium nitride (GaN) power devices in motor driving or power electronic conversion, and discloses a design method of a three-level active driving circuit for restraining bridge arm crosstalk of a GaN device, and the method comprises the steps that a circuit is connected in a bridge type topological structure, and the bridge type topological structure comprises an upper bridge arm and a lower bridge arm which are the same in structure; the upper bridge arm and the lower bridge arm are both divided into two parts, namely a traditional driving circuit and an auxiliary circuit, and the auxiliary circuit is divided into a negative voltage self-recovery circuit and a crosstalk suppression circuit. According to the invention, a negative voltage self-recovery circuit and a crosstalk suppression circuit are formed by using the output and reverse conduction characteristics of the charge pump and the auxiliary GaN device. The advantages of the two methods are combined, the defects of a traditional method are effectively overcome, the turn-off speed is increased, the turn-off loss is reduced, and the positive and negative crosstalk is reduced while the turn-on speed is hardly influenced and the reverse turn-on loss is not additionally increased. The overall design is flexible, efficient and reliable.

The invention discloses a three-level inverter dual-tracking model prediction control method and an inverter, and the method comprises the steps: constructing an integral sliding mode observer, and obtaining a current prediction value and a lumped disturbance estimation value through the integral sliding mode observer; calculating a voltage error of the inverter, and substituting the voltage error into the PI controller to obtain a voltage tracking control item; based on the voltage tracking control term, a switching state that minimizes the cost function is selected to control the inverter. The integral sliding mode observer is configured to calculate a current prediction error between a current prediction value of a current control period and a system output current, introduce an integrator to track the current prediction error, and generate an error function based on an output result of the integrator and the current prediction error. And feeding back a current predicted value and a lumped disturbance estimated value of the next control period through an error function. According to the invention, the method can achieve the quick estimation of the operation state of the inverter and the robust compensation of disturbance, reduces the steady-state tracking error, and reduces the total harmonic distortion of the inverter.

The invention discloses a clamping type multi-level converter and a control method, relates to the field of clamping, and aims to enable the voltage of a flying capacitor in the multi-level converter to be 1 / (N-1), 2 / (N-1)... (N-2) / (N-1) times of Vbus voltage (bus voltage) even if the voltage of the flying capacitor is in a steady state. The number of the clamping units is the same as that of the flying capacitors, and each flying capacitor is connected in series with the equivalent capacitors of the corresponding number of bus capacitors through the corresponding clamping unit when the multi-level converter switching tube is closed, so that each flying capacitor is clamped through the voltage of the corresponding number of equivalent bus capacitors; and the voltage of the flying capacitor in the multi-level converter can be ensured to be in a steady state without closed-loop control.

The present invention discloses a prediction method for a crosstalk spike in a half bridge of current-source inverter with silicon carbide devices, where, the prediction method includes calculation of the crosstalk voltage spike in the circuit of current-source type double-pulse test and analysis of the effect of each parameter on the magnitude of the crosstalk spike. The prediction method of the present invention analyzes the horizontal conduction crosstalk mechanism between the gate-source junction of the MOSFET caused by the high-frequency switching action of the silicon carbide (SiC) MOSFET and the SiC Schottky diode connected in series, and derives the prediction model for the crosstalk voltage spike in the half-bridge of current-source inverter. Based on the equivalent circuit of the current-source-type double-pulse test and the crosstalk-induced mechanism, the extreme value of crosstalk voltage spike is accurately predicted, which is helpful to analyze the effects of the drive circuit and the parameters of the power circuit on the crosstalk voltage spike through the prediction model.

A monolithic half-bridge gate driver includes a phase node terminal configured to be coupled to a phase node to which a high-side transistor and a low-side transistor of a half-bridge are coupled; a diode comprising an anode and a cathode, wherein the cathode is coupled to the phase node terminal; and a comparator comprising a first input terminal coupled to the anode of the diode for receiving a measurement value indicative of a phase voltage at the phase node terminal, a second input terminal coupled to a threshold source for receiving a threshold, and an output terminal configured to output a comparison result indicating whether the measurement value satisfies the threshold. The phase node terminal is configured to be connected to a high-side supply potential by the high-side transistor, and is configured to be connected to a low-side supply potential by the low-side transistor.

The invention, which relates to the technical field of the power adapter, discloses a protection circuit of a power adapter, comprising a power control module used for current sampling and high-frequency voltage transformation adjustment; the first output module is used for rectification, electric energy transmission and filtering processing; the second output module is used for rectifying and filtering; the anomaly detection module is used for carrying out overvoltage detection on the power supply control module; the voltage processing module is used for carrying out subtraction on the voltage threshold and the voltage provided by the second output module; the fault judgment module is used for controlling the signal transmission module to switch a transmission path when the power supply control module is not over-voltage and the first output module is over-voltage; the signal transmission module is used for transmitting the voltage output by the first output module or the voltage processing module to the feedback module; and the feedback module is used for voltage and current feedback. According to the protection circuit of the power adapter, overvoltage power-off protection can be carried out, the safety of the power adapter is improved, the power supply state of other normal output branches is ensured, and the power supply efficiency is improved.

The present teaching relates to method and system for charging a rechargeable battery deployed in an electric apparatus. The system resides in the electric apparatus. The system comprises a motor, an inverter, an output rectifier, a configurator, and a controller. The motor comprises a stator having a plurality of stator teeth and a plurality of stator windings wounded on the plurality of stator teeth. The inverter comprises a plurality of power switch devices. The configurator comprises a plurality of contactors coupled with the plurality of stator windings and the plurality of power switch devices. The controller controls the plurality of power switch devices and the plurality of contactors, so as to configure the system to operate in one of a traction mode and a charging mode.