2075results about "Ac-ac conversion" patented technology

A solid-state transformer is provided. The solid-state transformer includes a first stage, a first DC bus and a second stage. The first stage is configured to receive an AC power and convert the AC power into a first DC power. The first DC bus is electrically connected to the first DC power. The second stage is electrically connected to the first stage through the first DC bus, and is configured to perform isolated step-down DC / DC conversion on the first DC power to generate a second DC power. The first stage is configured to operate at a modulation index higher than 1, and the modulation index is defined by a ratio of twice AC voltage provided by the AC power to voltage across the first DC bus.

A modular multiport converter system includes a plurality of distributed controllers, associated with different ports of the system that are able to synchronize to ensure that power drawn from the system is equal to power supplied to the system with precise timing. The distributed controllers are able to receive a clock signal from a leader controller, or from a vice leader controller in the event that leader controller is unable to function.

The invention relates to a networking type three-level converter control system and a dynamic configuration method thereof, the networking type three-level converter control system comprises a redundant main control unit, a function unit, a six-phase power unit and a chopping unit, the redundant main control unit is connected with the function unit through an optical fiber, the function unit is respectively connected with the six-phase power unit and the chopping unit through optical fibers, and the chopping unit is connected with the six-phase power unit. The chopping unit is connected with the two ends of the direct current capacitor side of the inversion unit of the six-phase power unit; the main control unit and the pulse distribution unit are compact in sampling and modularized in design, small in occupied space, comprehensive in function, high in expandability and excellent in control performance, a dynamic configuration method is adopted, the redundant main control unit can be replaced on line, no power-on sequence requirement exists between the main control unit and each functional unit, and the power-on reliability is high. According to the invention, parameters of the pulse distribution unit can be forcibly updated on line, each functional module is independent, a more complex control system can be combined, and the system is convenient to use and maintain and is suitable for application occasions of complex control systems such as a network-forming converter and the like.

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.

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 discloses a multi-phase-multi-phase direct-type AC-AC converter based on an MMC and a control method of the multi-phase-multi-phase direct-type AC-AC converter. The AC-AC converter provided by the invention comprises a modular multi-level converter and N single-phase three-winding transformers, the modularized multi-level converter comprises X phase units, the input side is provided with m ports and connected with a first alternating current system, and the output side is provided with N ports and connected with a second alternating current system. Each single-phase three-winding transformer comprises a first winding, a second winding and a third winding, the first windings of the N single-phase three-winding transformers are respectively connected with N phases of a second alternating current system, and the second windings are connected with N output side ports of an upper bridge arm of the modular multilevel converter; and the third winding is connected with N output side ports of the lower bridge arm of the modular multilevel converter. The AC-AC converter is based on the principle of synthesis of differential-mode and common-mode voltage components of MMC bridge arms, and is combined with a three-winding transformer with an anti-dotted terminal, so that the number of sub-modules of the M3C topology can be further reduced, and the AC-AC converter has good expansibility and is suitable for application scenes with various special requirements.

A power converting apparatus includes a rectifier unit that rectifies first alternating-current power supplied from a commercial power supply, a capacitor connected to an output end of the rectifier unit, an inverter connected across the capacitor to generate second alternating-current power and output the second alternating-current power to a motor, and a control unit that controls an operation of the inverter and an operation of the motor using a dq-rotational coordinate system rotating in synchronization with a rotor position of the motor. The control unit extracts multiple frequency components from a q-axis current pulsation, which is a pulsatile component of a q-axis current, and limits the amplitude value of each of the extracted frequency components to control the amplitude of the q-axis current pulsation.

Examples of the disclosure include a power-conditioning system comprising a load output configured to be coupled to a load, a power-factor-correction circuit (PFC) comprising a first switching leg and a second switching leg, wherein the first switching leg and the second switching leg are configured to be controlled based on a first modulation index, an inverter comprising the second switching leg and a third switching leg, wherein the third switching leg is configured to be controlled based on a second modulation index, and a capacitor coupled to an inverter output of the inverter and being coupled in series with the load output.

Provided are a charging system, an electrical isolation system, a control system, and a shockwave device. The charging system is provided with at least two electrical isolation circuits, thereby improving the frequency of sending charging control signals and further improving the frequency of charging a shockwave generation apparatus. The electrical isolation system can greatly improve the dielectric strength of the electrical isolation system, reduce a leakage current on the surface of a shockwave generator, and ensure the safety performance of the shockwave generator. The shockwave device can effectively monitor the discharge energy of a shockwave emitter, thereby improving treatment safety, controllability, and working efficiency.

An electrical power apparatus for coupling between an electrical power supply and one or more electrical power loads includes: a plurality of dynamically dispatchable electrical energy storage components providing at least one of dynamically dispatchable energy storage thereto and energy retrieval therefrom; and a controller to dynamically control the operation of the one or more dynamically dispatchable energy storage components in order to dynamically match the electrical power supply to the one or more loads by dynamically storing energy in one or more of the dynamically dispatchable electrical energy storage components when the available electric power exceeds that required by the one or more loads, and / or dynamically supplying electrical energy from one or more of the dynamically dispatchable electrical energy storage components when the available electric power is less than that required by the one or more loads.

A power converter arrangement for power conversion in a single-phase power network, where the power converter arrangement comprises an input filter coupled to a first phase terminal to receive a first AC voltage, the input filter being configured to filter the first AC voltage to provide an input voltage; an electrical switching network comprising an array of bidirectional switches and an output terminal, the array of bidirectional switches being configured to generate a switched voltage from the input voltage at the output terminal. The electrical switching network comprises a decoupling capacitor to reduce undesirable oscillations at the output terminal; and a resonant circuit configured to convert the switched voltage into a supply voltage for supplying a load.

The invention provides a drive circuit for a frequency converter load, and relates to the technical field of frequency converters. Comprising a control module, a driving module, a power supply module, a signal acquisition and processing module and a load matching module, and the load matching module has impedance matching, tuning matching and shaping filtering functions and has universal adaptive driving capability for most types of motors and ultrasonic transducers; the power supply module adopts a high-speed MOS tube, the driving module adopts a high-speed driving chip to adapt to the high-speed MOS tube, the frequency application range is large, the DDS waveform generation module is adopted to realize PWM wave output of different frequencies, the change step length of the frequency is extremely low, and the change is smooth; a variable step size algorithm and an LADRC algorithm are combined, and the working resonant frequency of the variable frequency load can be automatically and accurately locked within a certain frequency range. A linear LADRC algorithm is adopted, behaviors of a driving circuit are adjusted through real-time measurement and estimation, and the method can adapt to changes and uncertainty of a motor and an ultrasonic transducer in a complex working environment.

The invention discloses an ultrasonic transducer series resonant frequency tracking method and an ultrasonic driving power supply, and the tracking method comprises the steps: calculating a current phase difference between a voltage signal and a current signal, determining a phase difference error and an error change rate through the combination of a target phase difference, and determining the resonant state of an ultrasonic transducer according to the comparison of the phase difference error and an error threshold value; if the current driving frequency is in the resonance state, keeping the current driving frequency unchanged; and if in a non-resonant state, correcting the driving frequency through a fuzzy PID algorithm. In order to cope with the sudden change of the load, the tracking method introduces an AI model to identify the load and predict the optimal driving frequency, and then the predicted optimal driving frequency is used as the current driving frequency. According to the invention, the response speed and the adjustment precision in dynamic frequency tracking are improved, and adaptive resonance driving and frequency control of the ultrasonic transducer under variable load and variable working conditions can be realized.

Provided are a bidirectional power supply apparatus and system. The bidirectional power supply apparatus includes: an alternating current input port configured to input an alternating current to the bidirectional power supply apparatus; an alternating current output port configured to output the alternating current to an alternating current device; a direct current input or output port configured to be capable of at least transmitting a direct current between the bidirectional power supply apparatus and a direct current device bidirectionally; a bidirectional energy conversion module configured to be capable of at least performing multiple energy conversions on electrical energy inputted to the bidirectional power supply apparatus; and a power management module electrically connected to at least the alternating current input port, the alternating current output port, and the direct current input or output port. The power management module is configured to control an energy conversion manner of the bidirectional energy conversion module according to a port connection status of the alternating current input port, the alternating current output port, or the direct current input or output port.

The invention discloses a power and current prediction control method and system for a doubly-fed motor grid-side converter, and relates to the technical field of converter monitoring, and the method comprises the steps: predicting a current value, an active power value and a reactive power value of the doubly-fed motor grid-side converter in a next control period according to a power prediction model and a current prediction model; designing an improved value function by considering active power, reactive power and a current component of a dq axis under a dq coordinate system, and obtaining the action duration of a voltage vector in a next control period by minimizing the value function; and based on the action duration of the voltage vector in the next control period, controlling the power switch of the grid-side converter of the doubly-fed motor. According to the method, power and current parameter control of the doubly-fed motor grid-side converter under the three-phase balance working condition is considered, and efficient control of the doubly-fed motor grid-side converter under the three-phase power grid voltage balance condition is achieved.

A power conversion apparatus includes: a three-phase inverter that supplies alternating-current power obtained by conversion to a load via a filter circuit including a three-phase reactor circuit and a three-phase capacitor circuit; a voltage detector that detects three-phase voltages that are voltages at respective connection points between the three-phase reactor circuit and the three-phase capacitor circuit; and a control device that controls operation of the three-phase inverter on the basis of the three-phase voltages detected by the voltage detector. The control device includes a calculation unit that calculates a zero-phase voltage obtained by adding together the three-phase voltages, a separation unit that separates an instantaneous value of the zero-phase voltage into an alternating-current signal and a direct-current signal, and a first determination unit that determines whether a ground fault occurs on the basis of an effective value of the alternating-current signal.

The invention relates to the technical field of frequency converters, and discloses a circuit for suppressing current oscillation of a frequency converter, which comprises a direct current bus voltage oscillation separation unit comprising an arithmetic unit and a PWM (Pulse Width Modulation) modulator; the PWM modulator is configured to calculate the DC bus voltage by using the arithmetic unit, and modulate the calculated DC bus voltage to obtain a modulation signal and a dynamic modulation ratio; wherein the dynamic modulation ratio is a factor which reversely changes along with the fluctuation of the direct-current bus voltage; a comparator configured to compare the corrected given voltage signal and the modulation signal to output a control signal; the corrected given voltage signal is obtained by correcting the given voltage signal according to the dynamic modulation ratio. In the circuit, the fluctuation voltage affects the given voltage, so that the corrected given voltage counteracts harmonic waves of the real-time direct-current bus voltage, and current oscillation is eliminated. The invention further discloses a method and device for suppressing current oscillation of the frequency converter, the frequency converter and a computer readable storage medium.

The present invention discloses an AC voltage regulating device and a control method, comprising input terminals (Ui1, Ui2) connected to a power grid, an input capacitor (3), an upper bridge arm (1), a lower bridge arm (2), an absorption module (4), and a discharge module (14). By adjusting the PWM duty cycle of the switch devices in the upper bridge arm (1) and the lower bridge arm (2), the total output voltage of Uo1 and Uo2 can be controlled to achieve a preset voltage value. The AC voltage regulating device and the control method of the present invention can realize direct voltage stabilization of AC power supply, significantly reduce the circuit complexity and device cost compared with the existing technology, and can effectively stabilize the power supply voltage of the power grid. The device has the advantages of fast response speed, low cost, simple control method, high reliability, convenient maintenance, and high efficiency.

A switching control system, including: switch units, configured to separately receive one of alternating currents and couple to a load; a detection unit, configured to detect the alternating currents; and a control unit, configured to, after receiving a switching signal, and in response to detecting that a power supply alternating current and a backup alternating current are in a polarity half cycle and a voltage difference is less than a preset voltage, perform: closing a first turn-on direction of a power supply switch unit; opening a second turn-on direction of a backup switch unit; closing a second turn-on direction of the power supply switch unit; and opening a first turn-on direction of the backup switch unit; where the first turn-on direction is opposite to a direction of the polarity half cycle, and the second turn-on direction is the same as the direction of the polarity half cycle.

The invention relates to the technical field of power transmission systems, in particular to a high-voltage direct-current power transmission receiving end tap switch control method, system and device and a medium. An initial tap switch gear is selected from the tap switch gear interval, and the lowest steady-state alternating current system voltage is determined based on the initial tap switch gear; calculating a minimum valve side ideal no-load direct-current voltage according to the minimum steady-state alternating-current system voltage; according to the minimum valve side ideal no-load direct-current voltage and the minimum direct-current resistance, the minimum steady-state direct-current voltage value of the sending end is calculated; calculating the maximum steady-state direct-current voltage value of the sending end based on the maximum alternating-current system voltage and the maximum direct-current resistance; and carrying out iterative adjustment on the tap switch gear based on the lowest steady-state direct-current voltage value of the sending end and the highest steady-state direct-current voltage value of the sending end to obtain an optimal target gear of the tap switch. According to the invention, the optimal control of the tap switch gear is realized, the action times of the tap switch are effectively reduced, and the stability and reliability of a power transmission system are improved.

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

Provided is a traction power supply system for rail transit, specifically a power unit for rail transit, and a control method. Distinguished from the architecture of a conventional traction power supply system for rail transit, a modularization-based power unit main circuit and a control method therefor are provided. The power unit main circuit comprises a high-voltage switch module, high-voltage modules, high-frequency transformers, low-voltage modules and an intermediate direct-current module. On the basis of a modular design concept, electrical isolation between high and low voltages and level conversion are implemented, thereby effectively reducing the difficulty in insulation design of a system and also improving the degree of redundancy and maintainability of the system. Furthermore, with regard to the phenomenon of voltage unbalance of multiple cascaded modules caused by differences in device parameters, a voltage equalization start logic and a control method are provided to effectively resolve the phenomenon of voltage unbalance between the cascaded modules, thereby reducing the impact of starting currents and improving the reliability of the system.

A single-stage AC-to-DC resonant converter is used to convert a three-phase AC power source into a DC power source. The single-stage AC-to-DC resonant converter includes a primary-side circuit, a resonant circuit, and a secondary-side circuit. The primary-side circuit includes three primary-side switch circuits, and each primary-side switch circuit is coupled to one phase of the three-phase AC power source. The resonant circuit includes three transformers, and primary-side windings of the transformers are respectively coupled to the primary-side switch circuits, and secondary-side windings of the transformers are coupled to the secondary-side circuit.

The invention discloses a high-precision voltage regulating system of a power frequency no-partial-discharge test transformer, and the system comprises a heterogeneous multi-stage power module which is formed by connecting an H-bridge unit group and a matrix converter in parallel, the H-bridge unit group outputs a fundamental voltage component, and the matrix converter compensates a high-frequency harmonic component; the multi-physics field digital twinning unit integrates an electromagnetic field solver, a thermodynamic model and a mechanical deformation simulation module and predicts the multi-physics field coupling state of the insulation system in real time; the dynamic impedance matching network comprises an adjustable inductor array and a digital capacitor bank, and automatically adjusts filtering parameters according to a load impedance measurement value; and the control module is used for deploying a deep learning model and is used for optimizing a modulation strategy and a protection threshold on line. According to the method, the voltage regulation precision and the waveform purity can be improved, the stability under the wide-range working condition is guaranteed, the breakdown hidden danger is recognized in advance through multi-physics field coupling simulation, and partial discharge development is restrained from the source.

A power converter, includes: a first terminal, a second terminal, a third terminal and a fourth terminal; stored-energy-source terminals, to which a stored energy source can be connected; four inverter bridge branches, which are formed from semiconductor switching devices, the inverter bridge branches each having a center tap, each center tap being assigned to one of the terminals, and the inverter bridge branches being interconnected and controllable such that electrical energy can be transferred bidirectionally between the stored-energy-source terminals and the first terminal, the second terminal, the third terminal and / or the fourth terminal; and a control unit, which is designed to control the semiconductor switching devices of the inverter bridge branches.

The invention provides a bidirectional flexible voltage regulation device for a power distribution network and a control method, and the device comprises a direct AC / AC type unidirectional voltage regulation topology which is connected with a power grid side and a load side of the power distribution network, and carries out the voltage regulation of the power distribution network; the mode change-over switch is connected with the direct AC / AC type one-way voltage regulation topology and is used for controlling the working mode switching of the direct AC / AC type one-way voltage regulation topology; the direct AC / AC type one-way voltage regulation topology is connected in series in a line of the low-voltage power distribution network through the mode change-over switch part, and bidirectional flexible voltage regulation when the voltage of the low-voltage power distribution network fluctuates or exceeds the limit is achieved. Through cooperation of the direct AC / AC type one-way voltage regulation topology and the mode change-over switch, a large-size transformer and a direct-current link are not needed, the operation of the mode change-over switch is controlled by detecting the voltage of the power grid, and real-time regulation of the output voltage is realized through closed-loop control; and bidirectional out-of-limit flexible voltage regulation of the power distribution network based on direct AC / AC type one-way voltage regulation topology and cooperating with the switch is realized.

A motor drive device includes a rectifier unit that rectifies first AC power supplied from a commercial power supply, an inverter that generates second AC power and output the second AC power to a motor, and a control unit that controls the operation of the inverter such that pulsation according to the power state of a capacitor is superimposed on a drive pattern of the motor, to reduce a charge and discharge current of the capacitor. The control unit performs load pulsation compensation control to compensate for load pulsation, power supply pulsation compensation control to reduce the charge and discharge current of the capacitor, and overload compensation control to reduce an inverter input current input to the inverter, while preferentially performing constant current load control to control the rotational speed of the motor.

The invention discloses a cascade H-bridge frequency converter fault early warning method, which comprises the following steps of: acquiring field current signals of each H-bridge unit, performing bidirectional verification on signal zero points by adopting a reverse zero-crossover reconstruction method, and generating a reconstruction timestamp matrix; carrying out phase space differential mapping based on the matrix, and extracting a feature matrix capable of representing internal dynamic characteristics of the system by calculating topological invariants such as track length and curvature; after dimension reduction is conducted on the feature matrix, affinity matching is conducted on the feature matrix and a preset fault mode library through an immune memory prediction mechanism, rapid fault recognition is achieved, and prediction feature vectors are generated through extrapolation; and the prediction features, the residual error and the memory activation degree are combined, a quorum sensing collaborative judgment model is introduced, the diffusion process of abnormal signals is simulated, collaborative and robust judgment of the fault type, the occurrence time and the influence range is achieved, and an early warning instruction is generated. According to the method, the accuracy, reliability and advance of fault early warning are remarkably improved.

Particular example embodiments described herein can provide for a system, an apparatus, and a method for a trans-inductor voltage regulator to reduce voltage hazards. The system, apparatus, and method can include, for example, a trans-inductor voltage regulator (TLVR) circuit that includes a multi-phase voltage regulator circuit; a plurality of phases of a primary winding connected in series. The plurality of phases includes a first phase and a last phase. The TLVR circuit can further include a ground located between the first phase and the last phase, and a compensation inductor situated such that at least one of the plurality of phases is between the ground and the compensation inductor.

The invention provides a power cooperative control method, device and system based on load removal and a medium. The method is applied to a micro-grid configuration flexible interconnection device for micro-grid fault protection. After the fault is positioned, a VSG low-voltage ride-through strategy is adopted to carry out current limiting, an importance quantification model is constructed for loads, and according to a real-time operation condition, a shearable load with the minimum influence on the system is screened to carry out priority removal; and dynamic power transmission adjustment of the flexible interconnection device is synchronously triggered, a micro-grid power flow path is reconstructed, and finally a fault is removed based on a current limiting and directional element protection method. According to the invention, system protection is realized by fusing intelligent load removal and flexible power adjustment, and the fault isolation speed and the stability of the microgrid system are effectively improved.