8784results about "Ac-dc conversion" patented technology

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 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.

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.

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.

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.

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.

The invention provides a modularized multi-level converter current control method based on feedforward analysis. The deviation between the direct-current side voltage and the reference value is stably monitored in real time based on the direct-current bus voltage, a first waveform signal is dynamically generated, and the direct-current side voltage fluctuation range is limited. According to the circulating current interphase voltage sharing, the dynamic deviation between the actual value and the rated value is calculated by collecting the capacitor voltage actual value of the bridge arm sub-module, and a second waveform signal is generated to balance the circulating current distribution of each phase of bridge arm. The loop current suppression based on feedforward analysis generates a third waveform signal to compensate for high-frequency loop current interference through real-time comparison of theoretical modeling and actual loop current components. In the modulation wave generation process, information in all aspects is integrated to accurately control the on-off state of the sub-module, so that the operation effect of the system is improved under the complex working condition, and the real-time performance and predictability of control are considered through combination of closed-loop adjustment and feed-forward compensation, so that the effectiveness of control is improved.

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 control system for an AC-DC converter includes a mixed-signal power controller and first and second gate drivers. The controller has a digital module and an analog module. The analog module has a current sensor generating a current sense voltage based on a sensed switch current. The digital module has a DC voltage sensor generating a DC sense voltage based on a DC bus voltage, and an AC voltage sensor generating an AC sense voltage and a binary polarity signal based on the AC voltage. The digital module induces the first gate driver to output first and second control signals for controlling a high-side switch and a low-side switch of a current shaping half-bridge based on first and second clock signals and the comparator voltage, such that an inductor current flowing through an inductor is proportional to a current command value.

The invention relates to the technical field of power conversion, and discloses an intelligent power converter system based on adaptive load regulation and a control method thereof. Comprising a power converter body, a plurality of sockets of different types are arranged on the power converter body, and a load sensing sensor, a micro-control unit, a step-down circuit and a bridge circuit are arranged in the power converter body; the load sensing sensor is electrically connected with the micro-control unit and is used for monitoring the power requirement of equipment connected with each socket in real time and transmitting a corresponding monitoring signal to the micro-control unit; the micro-control unit is electrically connected with the step-down circuit and the bridge circuit, and is used for controlling the step-down circuit and the bridge circuit to adjust output voltage and current according to a monitoring signal transmitted by the load sensing sensor; the micro-control unit controls the step-down circuit and the bridge circuit to automatically adjust the output voltage and current of the corresponding jacks according to the equipment power requirement monitored by the load sensing sensor, so as to realize the self-adaptive load adjustment of each jack.

The invention provides a photovoltaic energy storage inverter power coordination control method based on an adaptive algorithm, and relates to the technical field of data processing, and the method comprises the steps: collecting the output power data of a photovoltaic module, the state data of an energy storage device, and the load demand data of a grid connection point, and carrying out the normalization processing of the data; calculating to obtain an initial power distribution parameter of the current period; respectively calculating a load change trend factor and a power fluctuation trend factor based on the load demand data and the output power data of the historical period, and coupling the load change trend factor and the power fluctuation trend factor to form a trend coupling factor; carrying out self-adaptive repair through a trend coupling factor; combining real-time grid-connected point load demand data with energy storage device state data to generate a target power distribution instruction and an energy storage charging and discharging adjustment instruction, and respectively issuing the instructions to an inverter control unit and an energy storage device control unit; according to the invention, the accuracy of the photovoltaic energy storage inverter power coordination control method is improved.

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 dual inverter system includes a first inverter connected to one end of a stator coil of the motor and a second inverter connected to the other end. The controller can execute a dual mode in which the motor is driven by two inverters and a single mode in which the motor is driven by only one inverter. The controller closes the upper SW elements of all of the first and second inverters, opens all the lower SW elements, and closes the connection switch when the voltage at the DC end of the first inverter exceeds the threshold voltage. Alternatively, the controllers close all the lower SW elements of the first and second inverters to open all the upper SW elements and close the connection switches.

The invention provides a low-voltage ride-through control method for a grid-forming type grid-connected converter based on reactive power synchronization, and belongs to the technical field of converter low-voltage ride-through control. When the voltage of a power grid drops, a current amplitude limiting module in the power grid sends a control switching signal to trigger low-voltage ride-through control, and the low-voltage ride-through control is switched to a reactive power synchronization mode; a reactive power synchronous control gain KQs is calculated according to an inner loop gain coefficient Kcp, a current amplitude limiting value, a power grid voltage Vg and a grid side inductance Lgi, a virtual power angle reference value is generated by combining a set reactive power direct current component reference value QN, so that a power angle delta is stabilized in a range close to a normal working point, and a control effect is verified by comparing with a traditional method. According to the method, the system can quickly recover to a normal working state regardless of the duration of the fault and the severity of the fault, meanwhile, the system can effectively work under different power grid fault levels, and the robustness of the system is further enhanced.

The present application provides a converter and a chopper transistor blocking control method therefor. According to the chopper transistor blocking control method, when switching transistors in a converter need to be blocked, switching transistors in a primary side circuit connected to a transformer of the converter are blocked, and switching transistors in a secondary side circuit are blocked when the current on a branch where a secondary side winding in the transformer is located is zero, or batch blocking of the switching transistors in the secondary side circuit is completed after the current on the branch where the secondary side winding is located recirculates to zero, thereby avoiding overvoltage damage to the switching transistors caused by the current on the branch where the secondary side winding is located recirculating by means of the junction capacitance of the switching transistors in the secondary side circuit.

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 present invention provides a battery energy storage parallel equalization converter topology and a control method therefor. The battery energy storage parallel equalization converter topology comprises a series-connected battery energy storage parallel equalization converter, a main converter, and a plurality of groups of filter inductors; in the main converter, the input side of a DC / DC or DC / AC converter is connected in parallel to a parallel voltage-stabilizing capacitor, and the output side of the DC / AC or DC / AC converter is correspondingly connected to an AC or DC source load; the series-connected battery energy storage parallel equalization converter comprises a plurality of groups of small-capacity DC / DC converters and a common DC bus capacitor; the output sides of all the small-capacity DC / DC converters are connected in parallel by means of the common DC bus capacitor to form a common DC bus; the input side of one group of small-capacity DC / DC converters is connected in series to the input side of the main converter, and the input sides of other groups of small-capacity DC / DC converters are connected in series to a battery pack by means of the filter inductors, respectively. According to the present invention, in a battery charging and discharging process, only a small amount of power flows through the converter, reducing the capacity requirements of the converter, and reducing the transmission efficiency.

The invention provides a fault ride-through control method for a network construction type converter, and belongs to the technical field of energy storage converters and the like. The method comprises the following steps: firstly, measuring PCC voltage and power grid side current, calculating amplitudes of the PCC voltage and the power grid side current, and then judging whether the PCC voltage drops below a set threshold value or not; if not, keeping the active power reference and the voltage amplitude reference unchanged; and if so, performing active power reference modification: judging whether a current limiting strategy is triggered, if not, locking the PCC voltage reference as a measured value, and if so, gradually decreasing the PCC voltage reference by an increment value based on the measured value. According to the invention, accurate evaluation of the existence of the stable equilibrium point is realized; meanwhile, an improved fault ride-through control method is provided, active power reference and voltage amplitude reference are dynamically modified, so that the grid-forming converter is transited to a new stable balance point during a fault period, and current limiting, transient synchronization stability improvement, PCC voltage source characteristic maintenance and maximum fault current output can be taken into account.

This application relates to methods and apparatus for switched mode drivers. A BTL driver has a switch network operable in different switch states, wherein, in each switch state, each of first and second output nodes is connected to a respective one of a first switching voltage, a second switching voltage or an intermediate switching voltage between the first and second switching voltages which is provided by a driver capacitance. A controller is configured to control the switch network to operate in a sequence of switch states to generate a differential drive signal based on an input signal. The controller is configured such that operation of driver switch network in said sequence of switch states to generate said differential drive signal provides voltage regulation of the intermediate voltage provided by said driver capacitance.

A load connection state detection method for an energy storage power supply. The energy storage power supply comprises an inverter power supply. The method comprises the following steps: sampling an output voltage and an output current of the inverter power supply, and calculating output apparent power (S1); and determining whether the apparent power is less than a preset power threshold; if the apparent power is greater than the preset power threshold, a detection result being that a load is connected to the energy storage power supply; and if the apparent power is less than the preset power threshold, executing an active load online detection algorithm for secondary detection, and according to the secondary detection result, determining whether a load is connected (S2).

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 present invention provides a method for cooperatively suppressing a common-mode voltage and current harmonics of coupled three-level inverters, comprising: based on amplitude and phase angle of reference voltage vector, determining sector and region in which the reference voltage vector is located; selecting four basic voltage vectors with low common-mode voltage amplitudes to synthesize the reference voltage vector; writing volt-second balance equation based on selected basic voltage vectors, and calculating duty cycles thereof; and based on sector and region in which reference voltage vector is located, set value of voltage difference across capacitors on direct current side, and actual value of voltage difference across capacitors on direct current side, (1) updating duty cycles of basic voltage vectors, to realize separate control of capacitor voltage; and (2) designing and converting switching sequence into PWM drive signal of power switch, to control the coupled three-level inverter to operate.

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 provides a power factor correction method and system for AC-DC conversion of a server power supply, and relates to the technical field of server power supplies, and the method comprises the steps: collecting an input AC signal and a DC bus output signal, calculating a real-time power factor value, constructing a compensation function based on the power factor value, and calculating a deviation value; and generating a compensation parameter matrix through recursive calculation, processing a direct current output signal by adopting an adaptive filtering algorithm, fusing the direct current output signal with the compensation parameter matrix, calculating to obtain a current adjusting signal and a duty ratio adjusting signal, and accurately adjusting a power factor.