6245results about "Ac-dc conversion" patented technology

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.

A low voltage ride through control method for a grid-forming inverter based on dynamic internal potential adjustment comprises the following steps: detecting a voltage per unit value of a grid-connected point in real time, and comparing the voltage per unit value with a threshold value to judge a voltage drop event and trigger low voltage ride through control; dynamically calculating active and reactive power reference values through a reactive compensation equation and an active current limiting equation according to the voltage amplitude and the power reference value before falling during the ride-through period; inputting the active reference value into a virtual rotor motion equation to generate a reference phase, and outputting a phase reference signal in combination with a dual-mode phase compensation controller; superposing the reactive reference value with the reference voltage through a reactive voltage regulating ring to generate a voltage amplitude reference signal; synthesizing an internal potential according to the phase and the amplitude reference signal, and obtaining an inductive current reference value through virtual impedance control and current amplitude limiting; and finally, a driving signal is generated through the current inner loop controller and the modulation module. According to the invention, overcurrent can be effectively inhibited, rapid reactive power support is provided, and synchronous stability and smooth transition in a fault period and a recovery process are ensured.

Embodiments of the present disclosure provide method (400) for generating a unified control signal (Uunified) for power conversion system of control system (100). Method (400) comprising: measuring (402) output voltage of power conversion system, and output current of power conversion system; generating (404) first input control signal (U1,U1,processed) from first control systems based on measured output voltage of power conversion system and measured output current of power conversion system; generating (406) second input control signal (U2,U2,processed) from second control systems based on measured output voltage of power conversion system and measured output current of power conversion system; generating (408) first control signal (KU1,processed,K(t,Uexternal)U1) from first input control signal; generating (410) second control signal ((1-K)U2,processed, (1-K(t,Uexternal))U2,processed) from second input control signal; and generating (412) unified control signal (Uunified) by using interfacing function, first control signal and second control signal.

In accordance with some embodiments of the present disclosure, a multi-level power converter circuit includes a flying capacitor, a balancing capacitor to control a voltage across the flying capacitor, a plurality of converter switches, a control switch coupled between the flying capacitor and the balancing capacitor, and control circuitry to open and close the control switch based on states of at least two converter switches of the plurality of converter switches. In some embodiments, the multi-level power converter is a three-level buck converter, and the balancing capacitor maintains a voltage across the flying capacitor to be within a threshold range of half the input voltage of the buck converter. In some embodiments, a method for operating the multi-level power converter includes using control circuitry to operate the plurality of converter switches and the control switch to selectively couple the balancing capacitor to either side of the flying capacitor.

A converter (2) supplies a load (3) with electrical energy from a supply network (4). Using a desired power (P1*) of the load (3) and a state (Z) of the supply network (4), a control device (9) of the converter (2) determines a power (P2*) to be output by the converter (2) to the load (3). The control device (9) determines, using the power (P2*) to be output, control signals (C, C1, C2) for the converter (2) and controls the converter (2) by means of the control signals (C, C1, C2) such that the converter (2) outputs the power (P2*) to be output to the load (3). The control device (9) determines the state (Z) of the supply network (4) using variables (UZK, a, f) on which the determination of the control signals (C, C1, C2) is based.

The invention relates to the technical field of micro-grids, and discloses an inverter output waveform optimization control method, an inverter and a storage medium, and the method comprises the steps: constructing a switching period average model and an output waveform optimization function of a single-phase off-grid inverter, and carrying out the optimization control of the output waveform of the single-phase off-grid inverter based on the output waveform optimization function and the switching period average model, determining a calculation model of a modulation wave compensation signal; acquiring an input signal for controlling the output waveform of the inverter, performing double closed-loop control on the inverter based on the input signal, and outputting an original modulated wave signal; calculating a modulation wave compensation signal based on the input signal, an inductive current reference value generated in double closed-loop control and a modulation wave compensation signal calculation model; and superposing the original modulated wave signal and the modulated wave compensation signal to obtain an optimized modulated wave signal. According to the method provided by the invention, the modulation wave signal is compensated and optimized, and the purpose of optimizing the waveform quality of the output voltage when the single-phase off-grid inverter is loaded with the nonlinear load is achieved.

The invention discloses a TCM-mode-based Si-SiC hybrid power multi-phase staggered H-bridge converter structure and a control method thereof, according to the scheme, a three-phase staggered parallel topology of a two-phase low-frequency Si-IGBT bridge arm and a one-phase high-frequency SiC-MOSFET bridge arm is adopted, and a TCM control strategy is combined, so that zero voltage switching (ZVS) of a Si device is successfully realized, the switching loss is remarkably reduced, and the switching efficiency is improved. The system efficiency is greatly improved; and meanwhile, through pilot frequency interleaving and ripple compensation technologies, total output current ripples are greatly reduced, and optimal balance between system performance and manufacturing cost is realized while the power capacity of the converter is remarkably expanded and the dynamic response speed and the output electric energy quality are improved.

The invention provides a power distribution network single-high-frequency resonance rapid tracking and adaptive suppression method, a multi-mode dynamic cooperative adaptive suppression system is established based on a PCCVF adaptive method, and the damping characteristics of a power distribution network are remodeled by injecting compensation current into a power distribution network system so as to realize broadband resonance suppression of the power distribution network. The compensation current injection method comprises the following steps: step 1, detecting resonant frequency deviation of a power distribution network through real-time FFT (Fast Fourier Transform); 2, performing dynamic phase angle correction based on a phase prediction residual error of real-time frequency deviation; step 3, constructing a layered impedance remodeling module, and ensuring stable power transmission; 4, establishing a frequency-variable impedance model of the power distribution network based on resonance energy spectral density analysis, dynamically optimizing parameters through fuzzy logic of a bell-shaped membership function, and feeding harmonic compensation current into the power distribution network by using a space vector pulse width modulation technology; according to the invention, single high-frequency resonance can be effectively suppressed, the response and tracking performance of the system is improved, and the spectrum analysis efficiency and bandwidth occupation are optimized.

The invention discloses a hierarchical cooperative control method for a cascaded H-bridge frequency converter, and the method comprises the steps: distributing a disturbance signal following a spiral phase coding rule for each H-bridge unit, and enabling the vector sum of the phase of the group of signals to generate a plurality of energy quasi-zero moments in a preset disturbance period through design; at the quasi-zero moment when the energy is greatly suppressed, synchronously triggering all units to perform high signal-to-noise ratio data acquisition, and accurately identifying transient parameters representing dynamic characteristics of each unit based on the acquired data; and finally, performing closed-loop adjustment on an upper-layer power distribution strategy, a bottom-layer current loop and the like according to the identified transient parameters so as to compensate the dynamic response difference of each unit. According to the method, high-precision online parameter identification can be realized on the premise of not influencing stable operation of the system, and the power balance capability and transient stability of the system are remarkably improved.

The invention relates to a safe starting control method, device, equipment and medium for a bootstrap drive inverter, and the method comprises the steps: obtaining a detection voltage representing an output filter inductance voltage after responding to any starting event and before formally transmitting a drive signal; comparing the negative voltage with a preset negative voltage safety threshold value; only when the detected voltage is higher than the safety threshold, a driving enable signal is generated to allow the inverter to be normally started; otherwise, generating a driving blocking signal, carrying out detection and judgment again after waiting for preset time delay, and circulating the process until the system state enters the safe area; the method is realized by modifying a control algorithm, no power hardware needs to be added, the starting impact risk is eliminated with low cost, and the contradiction between the hardware limitation of a bootstrap drive circuit and the negative residual voltage possibly existing on the output inductance of the inverter is solved; therefore, the safety problem of direct connection between the impact current and the bridge arm during starting in an unfavorable initial state is solved.

The invention discloses a method for improving the stability of a system for sending out deep and far sea wind through a dual-port light converter. The method comprises the following steps: introducing a voltage feed-forward path comprising a phase compensator and a low-pass filter into an MMC differential mode control loop in the dual-port light converter; and a compensator parameter feasible region is calculated based on the phase characteristics of the oscillation risk frequency band, and the cut-off frequency of the filter is set, so that targeted phase compensation and impedance remodeling are realized, and the damping of the dual-port light converter is effectively enhanced. According to the method, the impedance characteristic of the dual-port light-weight current converter in the oscillation risk frequency band is remarkably improved, and a reliable technical path is provided for improving the stability of the dual-port light-weight current converter.

A reconfigurable flying capacitor multilevel input stage accepts a wide range of input voltages. The input stage divides and inverts a DC input voltage. Generally, output voltage regulation is achieved by adjusting the power switches' duty ratio in the input stage for non-resonant converters and by adjusting the switching frequency for resonant converters.

The invention discloses a construction method and a modulation method of a three-port multi-frequency MMC topology based on bridge arm multiplexing, and relates to the technical field of power electronics. The construction method comprises the steps that sub-modules of a traditional double-bridge-arm MMC are integrated and optimized into a three-bridge-arm structure through a current conversion branch, independent energy interaction of three ports is achieved through an auxiliary bridge arm, multi-frequency operation modes of power frequency, frequency division, direct current and the like are supported at the same time, and therefore the utilization rate of the bridge arm sub-modules is increased, and the energy utilization rate of the MMC is increased. And the overall size and the manufacturing cost of the converter are reduced. Based on three-port multi-frequency coordination control and power balance requirements, a modulation method of the topological structure is provided, a multi-frequency coordination modulation strategy is adopted, frequency offset is performed through an auxiliary bridge arm to reduce cross interference of port frequency, and output waveform quality is improved through multi-objective optimized capacitor voltage balance control. And meanwhile, direct-current side faults are effectively eliminated by means of the auxiliary bridge arm.

The present invention provides a topology, method and system for bi-directional power conversion of excitation power supply for power battery testing, wherein the topology comprises a three-phase PWM (pulse width modulation) converter, a high-frequency isolation three-level LLC (logical link control) resonant converter and a DC-DC (direct current) converter forming a topology structure for a three-stage power conversion; an input end of the three-phase PWM converter is connected to a power grid side; the high-frequency isolation three-level LLC resonant converter is connected between the three-phase PWM converter and the DC-DC converter in series and is configured for realizing bi-directional DC voltage conversion and isolation, and to raise a busbar voltage between the high-frequency isolation three-level LLC resonant converter and the DC-DC converter; and, the DC-DC converter is configured to generate charging and discharging excitation currents for a power battery testing.

According to some embodiments, a multi-level power converter, includes an output terminal, a reference terminal, an inductor, a flying capacitor, a first switching stage including a first switch connected to the output terminal and connected to the flying capacitor at a first node, and a second switch connected to the flying capacitor at a second node and connected to the reference terminal, a second switching stage including a third switch connected to the first node and the inductor, and a fourth switch connected to the inductor and the second node, and a pre-charge unit connected to the flying capacitor and the output terminal and configured to pre-charge the flying capacitor based on a voltage at the output terminal during a start-up cycle of the multi-level power converter.

The invention discloses a cooperative control system for an input-series output-parallel dual-active-bridge inverter, and relates to the technical field of power electronic converter control, an input voltage equalizing control IVSC loop is set for m-1 DAB sub-modules, and input voltage equalization of the DAB sub-modules is realized by adjusting phase shift angles of the sub-modules; an output voltage control OVC loop is set for the output DC bus voltage of the whole ISOP-DAB system to stabilize the DC bus voltage, a PIR controller is adopted in the OVC loop, and the resonant frequency is set to be twice of the fundamental frequency of the AC side, so that selective high gain is provided at the position, the frequency doubling fluctuation of the DC bus voltage is inhibited, and the frequency doubling fluctuation of the DC bus voltage is inhibited. According to the method and the device, the regulation quantity of the IVSC loop and the regulation quantity of the OVC loop are superposed to carry out cooperative control, so that the effective suppression of the frequency doubling fluctuation of the DC bus voltage and the automatic equalization of the power of each module are accurately realized on the premise of not increasing the hardware complexity.

This invention discloses a method and system for suppressing capacitor voltage fluctuations in SiC MMC submodules, belonging to the field of electronic power technology. Based on the analysis results of the optimal broadband harmonic circulating current injection boundary and order for SiC MMC submodules, an optimized model for submodule capacitor voltage fluctuations is determined that simultaneously injects 2nd, 4th, and 8th harmonic circulating currents and 3rd harmonic voltages, which can fully utilize the higher control bandwidth characteristic of SiC MMC. By solving the optimized model for submodule capacitor voltage fluctuations, the amplitude and phase of the reference values ​​of the 2nd, 4th, and 8th harmonic circulating currents to be injected, as well as the amplitude and phase of the corresponding 3rd harmonic voltage, are determined. Then, by injecting 2nd, 4th, and 8th harmonic circulating currents and jointly injecting the 3rd harmonic voltage, broadband harmonic joint injection is achieved, reducing the capacitor voltage fluctuations of the submodule and realizing a method for suppressing capacitor voltage fluctuations in SiC MMC submodules with high suppression effect.

Responsive to a voltage across a capacitor being greater than a voltage across a traction battery, a controller may open switches such that charge current from a DC charger flows through a diode to the traction battery without following through coils of an electric machine and without flowing through an inverter.

The invention discloses a parallel operation data interaction system and method for hybrid energy storage inverters, and relates to the technical field of power systems, and the system comprises a parallel operation data interaction center, a data collection and monitoring module which is used for collecting load data in a power distribution network and monitoring the operation state of each hybrid energy storage inverter, performing feature analysis to extract load operation features to obtain a load operation feature sequence table; and the load prediction module is used for obtaining a load trend index by using the historical data and the load operation characteristics in the load operation characteristic sequence table in combination with a pre-trained load prediction model, and analyzing the change trend of the load. By collecting load data and monitoring the operation state of the inverter, the operation condition of the system can be comprehensively mastered, abnormity can be found and processed in time, the output of the inverter is adjusted in advance and the operation mode is switched in combination with the load prediction model, load fluctuation and power grid faults are effectively handled, and the stability and reliability of the power system are remarkably improved.

This document describes, among other things, a vehicle power system that includes a traction battery, a six-phase inverter divided into two groups of six switches, a six-phase motor, and a pair of switches. In drive mode, the switches configure the inverter to connect the traction battery and the motor. In plug-in mode, the system reconfigures so that one group of switches connects an AC source to the motor, while the other group connects the motor to the traction battery.

The invention discloses a non-contact power supply three-stage control system based on series redundancy, and belongs to the field of non-contact power supply control. Comprising a power correction module, a voltage conversion module, a full-bridge inversion module, a cooperative control module, an analysis adjustment module, a monitoring switching module, a simulation maintenance module, a communication security module, a remote interaction module, an energy efficiency optimization module and a diagnosis recording module. High conversion efficiency can be dynamically kept under different loads and working conditions, energy loss is reduced, electric energy quality is remarkably improved, damage and misoperation under abnormal working conditions are prevented, high-reliability continuous power supply is achieved, PID parameters can be dynamically adjusted or direct control quantity can be generated, the system adapts to complex and changeable operating environments, and failure rate and shutdown loss are reduced.

The invention relates to the technical field of electronics, and discloses a boost circuit control method and device, computer equipment and a storage medium, and the method comprises the steps: detecting a state change event in a boost circuit; calculating a voltage difference value between the front-end voltage value and the rear-end voltage value in the booster circuit, and determining a corresponding target control strategy based on the state change event and the voltage difference value, the target control strategy at least comprises a step of determining a corresponding target voltage value and a feed-forward current value based on vehicle driving parameters and working condition parameters of a load motor so as to execute voltage regulation, or a step of determining a corresponding feed-forward duty ratio based on a rear end voltage value of a booster circuit so as to execute voltage regulation; and executing corresponding control operation on the booster circuit according to the target control strategy. The problems that in the prior art, due to the fact that a control strategy of a booster circuit is fixed, and a state change event and voltage difference value dynamic adjustment are not combined, voltage adjustment response lags behind, and stability is insufficient are solved.

The invention relates to the technical field of bidirectional PCS, and discloses a bidirectional PCS converter multi-target power balance optimization method and system based on model predictive control. According to the method, real-time operation parameters are analyzed by using a first-order lag initial model, prediction of power disturbance in a plurality of control periods in the future is realized, power balance optimization is converted from passive response to active pre-judgment, and a linear time-varying prediction model is constructed, so that the real-time performance of power balance optimization is improved. According to the method, the evolution trajectory of the direct current bus voltage in a period of time in the future is predicted, the power balance optimization behavior is continuous and prospective through a rolling optimization mechanism of prediction, evaluation and preferential selection, and meanwhile, the three targets of ensuring voltage stability, reducing switching loss and suppressing current harmonic content are fused into power balance optimization, so that the power balance optimization efficiency is improved. The problems of control hysteresis and target singleness existing in a traditional control method are solved, and quick and accurate power balance control of the bidirectional PCS is realized.

The invention relates to the technical field of power electronic control, and provides a soft start control method for a three-phase PFC (Power Factor Correction), a PFC controller and a power supply system.The soft start control method comprises the steps that when a PFC start instruction is received, an initial target voltage value is set as an actual value of current bus voltage; maintaining the initial target voltage value for a first preset duration; after the initial stable state, sampling in real time to obtain the actual value of the current bus voltage, and calculating the absolute value of the voltage difference between the actual value of the current bus voltage and the current target voltage value; judging whether the absolute value of the voltage difference is smaller than or equal to a preset trigger threshold value; if yes, adding a preset voltage step value to the current target voltage value; if not, keeping the current target voltage value unchanged; and recursive control of the current bus voltage is executed circularly until the updated current target voltage value reaches the final target voltage value. According to the mode, the starting rapidity and the stability of the boosting process are balanced.

The invention is suitable for the technical field of flexible power distribution of a power system, and discloses a modular multilevel converter multi-objective optimization method, system and device based on model predictive control and space vector modulation, and a medium. Obtaining an output current reference value and a circulating current reference value; obtaining a reference voltage vector based on the output voltage reference value, and screening out a plurality of groups of redundant voltage vector sequences through a space vector diagram; performing performance evaluation through rolling optimization by combining each redundant voltage vector sequence with a multi-target cost function to obtain an optimal voltage vector sequence; and on the basis of the optimal voltage vector sequence and the corresponding duty ratio, a switching signal for driving each sub-module switching device of the MMC is generated, and multi-target cooperative control is realized. The three targets of reference output current tracking, circulating current suppression and sub-module capacitor voltage balance are met, and the dynamic response capability, efficiency and reliability of MMC system operation are comprehensively improved.

The invention discloses a specific grid-connected current harmonic suppression method and device for an energy storage converter, and belongs to the technical field of power systems, and the method comprises the steps: obtaining a given current value of a fundamental current loop, and carrying out the dq / abc conversion to obtain a three-phase current reference value; acquiring a three-phase current value of a power grid side, and subtracting the three-phase current value from the three-phase current reference value to obtain a harmonic current value; converting the harmonic current value to a target subharmonic synchronous rotating coordinate system to obtain a target subharmonic current value; extracting the target sub-harmonic current value in a direct current form through a low-pass filter, and sending the target sub-harmonic current value to a PI regulator for regulation to obtain a harmonic voltage compensation amount; and injecting the harmonic voltage compensation amount into a modulation wave to realize suppression of the target subharmonic current. According to the invention, the grid-connected side current harmonic of the energy storage converter can be effectively suppressed, and the grid-side current quality is improved.

A conversion control circuit for controlling a stackable multi-phase power converter, the conversion control circuit including: a master transfer terminal, wherein a master transfer trigger signal is coupled to plural master transfer terminals of plural parallel-connected conversion control circuits; and a master transfer circuit configured to generate or receive the master transfer trigger signal through the master transfer terminal, wherein the master transfer trigger signal is generated according to an output voltage or an output current of the output power, or a pulse-width modulation related signal; when the master transfer trigger signal switches to an enabled state, the conversion control circuits perform a phase sequence swapping procedure, which includes: the master transfer circuit triggering a transfer of a master role from the stackable sub-converter originally acting as the master circuit to another stackable sub-converter of the stackable sub-converters.

The invention discloses a narrow pulse suppression method and device for dynamic adjustment of dead time, a medium and a controller, and the method comprises the steps: presetting the dead time of M periods in the future according to the real-time state of a motor and the dead time and current change rate of the first N periods, and outputting a working condition label at the same time, N and M being positive integers; determining target dead zone time Td according to the working condition label and the dead zone time of the M periods in the future; determining a dead zone time ratio Dd according to the target dead zone time Td, constructing an interval section of a PWM signal according to the dead zone time ratio Dd and a narrow pulse time ratio Dp, and constructing an upper bridge arm duty ratio function Dt and a lower bridge arm duty ratio function Db corresponding to each interval section according to the dead zone time ratio Dd and a duty ratio instruction Dm of the PWM signal; according to the interval section where the duty ratio instruction Dm of the PWM signal is located, a duty ratio function of the corresponding interval section is called, and a target PWM signal is output.

The invention relates to the technical field of power electronic conversion, and discloses a high-efficiency rectification conversion system and a control method thereof, and the system comprises the following modules: a detection module, an input compatible module, a hybrid power device module, a control module, a thermal management module and a frequency modulation module. The control method comprises the following steps: acquiring input power grid voltage, output current and load state parameters; calculating an input voltage phase difference; dynamically selecting the type and channel configuration of the silicon carbide or gallium nitride power device according to the load rate; outputting a device configuration instruction and a switching frequency control instruction; adjusting the cooling system through the evaluated thermal state of the conversion system; and the control module receives the control instruction output by the control module and is used for implementing a corresponding pulse width modulation strategy. According to the method, a multi-system power grid identification and self-adaptive topology switching strategy is adopted, the technical effect of automatically configuring the optimal rectification architecture under different input types is achieved, and the problems of response delay and poor compatibility of the method in the environment of variable power grid types are solved.

The invention relates to the technical field of power electronic control and new energy power generation, and discloses an energy storage type photovoltaic off-grid inverter control method and system. The method comprises the following steps: acquiring an analog voltage signal and an analog current signal, and inputting the analog voltage signal and the analog current signal into a preset adaptive filter to obtain a disturbance component sequence; calculating a disturbance current sudden change degree, and if the disturbance current sudden change degree exceeds a preset sudden change threshold, constructing a to-be-counteracted current vector; determining a target phase lead angle according to the to-be-counteracted current vector and a preset transformer phase lag model, and generating a correction time domain compensation signal; generating a comprehensive modulation signal and an inverter switching instruction sequence to drive an inverter; updating a filter coefficient based on the distortion rate and determining a compensation voltage gain; and performing closed-loop correction on the sampling trigger time sequence of the analog current signal according to the system loop transmission delay to obtain a calibration current sequence. The method can effectively overcome the phase lag of the transformer and the transmission delay of hardware, and improve the electric energy quality under the nonlinear load.