1514results 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 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.

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.

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.

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 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.

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.

A power electronic transformer includes three modules, each module including a first sub-module; a second sub-module; the third sub-module comprises a first power conversion module which comprises N first power conversion units, and the input ends of the N first power conversion units are connected with the N output ends of the first sub-module in a one-to-one correspondence mode; the second power conversion module comprises M first power conversion units, and the input ends of the M first power conversion units are connected with the M output ends of the second submodule in a one-to-one correspondence mode. One terminal of a first input end of a first sub-module of the three modules is connected with three phases of a first three-phase alternating current in a one-to-one correspondence mode, and the other terminal of the first input end of the first sub-module of the three modules is connected with three phases of a second three-phase alternating current in a one-to-one correspondence mode. One terminal of the first input end of the second sub-module of the three modules is connected with three phases of a first three-phase alternating current in a one-to-one correspondence mode, the other terminal of the first input end of the second sub-module of the three modules is connected with a neutral point, and the output ends of the N first power conversion units and the output ends of the M first power conversion units are connected in parallel to form a direct-current bus used for supplying power to a load.

The invention discloses a current distortion suppression method and device for an N-phase AC-AC conversion system, and relates to the field of voltage conversion control, and the method comprises the steps: determining the ideal sine reference current of an xth phase, obtaining the actual input current of the xth phase in a current control period and the actual output current of the xth phase corresponding to an inductive load, and determining the current variation of the xth phase; and determining a difference value between the ideal sine reference current of the x-th phase and the actual input current as a real-time current distortion error signal of the x-th phase, further determining a compensation duty ratio of the x-th phase for suppressing current distortion by combining a preset duty ratio compensation strategy, and further determining a target duty ratio of the x-th phase as a target PWM signal. According to the scheme, the input current of each phase can be monitored, inductive load disturbance can be responded, the compensation duty ratio of the x-th phase used for restraining current distortion can be dynamically adjusted so as to determine the target duty ratio, the current distortion of the input current can be effectively restrained, and the input current can follow ideal sine reference current.

A electrical power system comprises: an electrical machine operable to output AC; a DC electrical network; a power electronics converter connected between the AC output of the electrical machine and the DC electrical network and including a plurality of transistors and associated diodes connected in parallel with the transistors; and a controller configured to control switching of the transistors of the converter so that, during normal operation of the electrical power system, the converter rectifies the AC output of the electrical machine to supply the DC electrical network with DC electrical power. The controller is further configured, responsive to a determination to the effect there is a fault in the DC electrical network, to control a voltage source, to inject a voltage to bias the diodes of the converter, and to control the switching of the transistors to control a level of current supplied to the faulted DC electrical network.

The present disclosure describes moving one phase of the TLVR topology from a primary side of the topology to a secondary side. By doing so, the secondary side phase is able to drive the TLVR secondary winding current with equal magnitude and opposite direction to the primary winding current for both transient and DC. Therefore, all the TLVR inductors see zero bias of magnetic flux in the cores under any loading conditions. With this feature, TLVR inductor size can be significantly reduced by reducing the saturation current. As another option, the inductor size can remain unchanged and the Zero-Bias TLVR can be optimized for power efficiency by increasing the inductance. With higher inductance, the voltage regulator switching frequency can be reduced accordingly to boost up the power efficiency.

A power conversion device includes a rectification unit that rectifies first alternating current (AC) power supplied from a commercial power supply, a capacitor connected to an output end of the rectification unit, an inverter that converts power output from the rectification unit and from the capacitor into second AC power, and outputs the second AC power to a load including a motor, which inverter is connected to both ends of the capacitor, and a control unit that controls operation of the inverter to output the second AC power from the inverter to the load to reduce current flowing to the capacitor, which second AC power includes a pulsation that depends on a pulsation of power flowing from the rectification unit to the capacitor. No discharge circuit and no overvoltage protection circuit are provided for the capacitor.

The present application relates to a converter control method, a converter, and a chip. The converter comprises an alternating-current side half-bridge circuit and a controller, and the method is used in the controller. The converter control method comprises: when the alternating-current side half-bridge circuit satisfies a zero-crossing switching condition, switching the control mode of the alternating-current side half-bridge circuit from a first mode to a second mode, wherein the second mode comprises: switch devices located on a same bridge arm are turned on in a preset sequence or turned off in a preset sequence, and corresponding switch devices located on different bridge arms are complementarily turned on. The converter control method has high reliability.

The invention discloses a high-efficiency converter for adjusting the voltage of a power grid, and belongs to the technical field of power electronics. The converter comprises a first voltage regulation circuit, a second voltage regulation circuit, a filter circuit, a detection circuit and a control circuit. By detecting the amplitude difference between the power grid voltage and the load voltage, the control circuit automatically switches the Buck working mode or the Boost working mode, and stable alternating current output in a wide input voltage range is achieved. The invention has the advantages of compact structure, high efficiency, fast response, small harmonic wave and the like, and is suitable for industrial and civil occasions with large-range fluctuation and frequent power grid voltage.

The invention belongs to the field of active frequency support of power electronic equipment in a network-construction-type flexible direct-current power transmission system, particularly discloses a control parameter adaptive design method and system of a network-construction-type flexible direct-current converter, and aims to solve the problems of insufficient system inertia support and oscillation caused by fixed parameters in a wide-range disturbance scene. The method comprises the steps that a receiving-end converter extracts the deviation value, the change rate and the acceleration of the frequency of a power grid by monitoring the electrical quantity of a grid-connected point in real time, and the system operation state is divided into three modes of steady-state maintenance, fluctuation early warning and emergency response based on threshold judgment; calculating a virtual inertia coefficient by using a saturated nonlinear function, and cooperatively solving a damping coefficient in combination with small signal stability analysis; and establishing a virtual inertia-damping parameter feasible region and outputting the virtual inertia-damping parameter feasible region to a receiving end converter station controller. The limitation of traditional fixed parameter design under the disturbance working condition is broken through, the frequency supporting capacity of the system can be remarkably improved, and the stability problem caused by frequent parameter change is avoided.

Provided are a method for controlling a cycloconverter circuit, a cycloconverter circuit, and an isolated converter. The cycloconverter circuit is configured to perform alternating current to alternating current conversion and includes a plurality of switch elements connected in a plurality of current paths. The plurality of switch elements are divided into a plurality of groups of switch elements. Each group of switch elements includes at least one switch element disposed in each current path. The method includes: when the cycloconverter circuit is in a zero-crossing detection stage, controlling a first group of switch elements to be turned on complementarily and a second group of switch elements to switch between an on state and an off state. During a dead time between drive signals for the first group of switch elements, a first target switch element in the second group of switch elements is turned on.

The present application relates to a rectification control system, a charger and a control method for a charger. The rectification control system includes: a Vienna rectifier, which includes input terminals and output terminals, an output capacitor circuit, and a rectifying circuit which includes a u-phase bridge arm branch, a v-phase bridge arm branch and a w-phase bridge arm branch, each bridge arm branch comprising a switch device and a bidirectional switch unit which are connected in series; a voltage acquisition unit, which is connected to the three input terminals and is configured to acquire voltages Uuv, Uvw and Uwu; a fault detection unit, which is connected to the bidirectional switch units and is configured to detect whether any of the bidirectional switch units fails; and a control unit, which is connected to the voltage acquisition unit and the fault detection unit and is configured to control closing or opening of three switch devices according to voltage input format, voltage connection mode and detection result of the fault detection unit, so as to switch circuit and working mode, making a charger suitable for applications in multiple scenarios and multiple formats.

The invention provides a solid-state transformer. The solid-state transformer comprises a first-stage circuit, a first direct-current bus and a second-stage circuit, the first-stage circuit structure is used for receiving alternating-current electric energy and converting the alternating-current electric energy into first direct-current electric energy. The first DC bus is electrically connected to first DC electric energy. The second-stage circuit is electrically connected to the first-stage circuit through a first DC bus, and is configured to perform isolated step-down DC / DC conversion on the first DC electric energy to generate second DC electric energy. The first stage circuit is configured to operate with a modulation index greater than 1, and the modulation index is defined as a ratio of twice an AC voltage provided by the AC power to a voltage on the first DC bus.