250 results about "Ring current" patented technology

Methods and apparatus for dimming light sources are described herein. In certain embodiments, a bias circuit selectively biases a solid state switch during a portion of half-cycle of a line voltage after a settable delay. In some embodiments, the delay of the bias circuit is adjustable by a user, which varies the amount of energy provided to a light source, and the light generated there from. A charge circuit biases the switch for a period of time in the event the bias circuit experiences an operating condition (a ringing current) that may cause the switch to become open during the half-cycle of the line current. As a result of the charge circuit, the light source coupled to the line current does not experience substantial flickering and is compatible with low power compact fluorescent lights. The dimmer can be combined with other components to form a light harvesting system.

Analyzing interactions between vias in multilayered electronic packages that include at least two spaced-apart conducting planes, and multiple vias that connect signal traces on different layers. Voltages at active via ports are represented as magnetic ring current sources, which generate electromagnetic modes inside the plane structure. Substantial electromagnetic coupling between vias occurs. A full-wave solution of multiple scattering among cylindrical vias in planar waveguides is derived using Foldy-Lax equations. By using the equivalence principle, the coupling is decomposed into interior and exterior problems. For the interior problem, the dyadic Green's function is expressed in terms of vector cylindrical waves and waveguide modes. The Foldy-Lax equations for multiple scattering among the cylindrical vias are applied, and waveguide modes are decoupled in the Foldy-Lax equations. The scattering matrix of coupling among vias is then calculated for use in determining signal reflection, transmission, and/or coupling in the electronics package.

The invention discloses a multi-terminal VSC-HVDC grid-connected transmission system controlling method applied to a large wind power plant. Wind power plant side convertor station outer ring power conducts inner ring current PI control, a grid field side convertor station outer ring direct voltage conducts inner ring current feedback linearization decoupling control, and therefore response characteristics and dynamic performance of a controller are improved. When operation of the wind power plant fluctuates greatly and a system loses capacity for adjusting the direct voltage, multi-terminal direct voltage control of direct voltage deviation is led into other convertor stations of the wind power plant for replacing a grid side convertor station to execute a voltage regulating task, therefore, power balance is maintained, normal operation of the system is ensured, and the effect that the system operates stably at a new operating point is also ensured.

The invention aims to solve the technical problems of obvious stator current distortion and zero-sequence ring current of the direct current bus-shared open-end winding asynchronous motor caused by pure suppression of the zero sequence ring current in a modulation strategy link and neglecting of non-linearity and counter electromotive force zero sequence component in the prior art; on the basis, the invention provides a space vector PWM modulation scheme with controllable zero sequence voltage; by performing active control on the zero sequence voltage of the direct current bus-shared open-end winding asynchronous motor system, suppression of the zero sequence ring current is realized; and meanwhile, use of a zero vector is avoided, so that the common-mode voltage of the open-end winding asynchronous motor system is lowered.

The invention relates to a method of controlling running of a modularized multi-level converter in a low frequency model, which belongs to the technical field of controlling multi-level power electronic converters. The method comprises the following steps: setting high frequency common mode voltage and high frequency ring current both required to be superimposed, revising a switching function of a submodule and bridge arm current, obtaining an expression of capacitance voltage differential coefficient of the submodule according to volt-ampere characteristics of capacitance of the submodule, and in order to allow the capacitance voltage of the submodule to only have high-frequency component, assuming high frequency common mode voltage is known to obtain a expression of the high frequency circular current; comparing a running frequency with a critical frequency to obtain frequency model selection signals, combining an energy control and a circular current control of a phase unit of the modularized multi-level converter, determining whether the high frequency common mode voltage and the high frequency circular current are required to be superimposed to an original instruction or not according to the frequency model selection signals, and generating voltage required to be superimposed in the bridge arm of the phase unit of the high frequency circular current by controlling. The method is easy to realize and strong in universality, and provides reference for low frequency application of the modularized multi-level converter.

The invention relates to a photovoltaic model establishment method applicable to the dynamic overall-process simulation of a power system. A photovoltaic generation module is modeled, a temperature factor and an illumination intensity factor in the medium and long-term process have the characteristics of fluctuation and indeterminacy, and an implementation method of a photovoltaic maximum power tracing model for the dynamic overall-process simulation of the power system is provided in consideration of the influence on photovoltaic generation caused by the change of the two factors. The photovoltaic maximum power tracing model adjusts the working voltage of a photovoltaic cell panel according to the volt-ampere characteristics of a photovoltaic power supply by using a maximum power point tracing control method, so that the photovoltaic cell panel can work in a maximum power output state, solar energy is utilized to the greatest extent, and the efficiency and performance of the photovoltaic generation are effectively improved. An inverter effectively controls the injection current of axes d and q by virtue of an inner ring current control loop and an outer ring current control loop, so that active power and reactive power can be controlled. The whole model meets requirements for electromechanical transient overall-process simulation and medium and long-term dynamic overall-process simulation of the power system.

The invention discloses a fluctuation thermoacoustic generation system, which comprises the following loop parts in sequence: cold junction heat exchanger, heat regenerator, heater, heat buffer pipe, hot junction heat exchanger, ring-shaped connection pipe and line generator in the pipe, wherein the generator contains a cylinder with one end of casing on the pipe and the other end with line sliding bearing; a double-loop magnetic-inductive soft iron with ring orifice is set in the cavity between cylinder and casing; the permanent magnet is inserted in the outer ring magnetic wall of soft iron; the coil rack is fixed on cylinder inner wall with part of coil in the ring orifice; the elastic or quality component is set in the hot junction pipe; the quality component does shift sliding along the elastic element; the elastic or quality phase modulation component is set in the greenhouse pipe; the quality component does shift sliding along the elastic phase modulation element. The invention can adjust the phase difference of pressure fluctuation and bulk flow fluctuation, which feedbacks the acoustic power to accomplish high effective Stirling cycle as well as inhibits the loop ring current to improve property of entire machine.

The invention provides a direct-current microgrid control method and system based on hierarchical management. An overall control strategy of a direct-current microgrid is decomposed into an equipmentmanagement layer and a bus control layer structure. All parts of the microgrid are regulated based on own characteristics and working modes at the equipment management layer; and at a hybrid energy storage effect link, current controlling without energy storage battery compensation is carried out, so that the energy storage adjustment response speed and stability are improved. At the bus control layer, a set working mode controller carries out working mode division according to a fluctuation range of a bus voltage and the residual power of the battery, so that the system is able to carry out switching in different working states; and the working modes of all units of the equipment management layer are set based on different working modes, so that the stable operation capability of the direct-current microgrid is enhanced. And with consideration of the parallel energy storage control method, an adaptive droop coefficient regulator is established, so that the ring current influence between lines is suppressed and the time of reaching balancing of the parallel energy storage is shortened.

The invention discloses a reactive power control circuit of a single-phase photovoltaic inverter. The reactive power control circuit comprises a bus voltage supporting capacitor, a single-phase full-bridge inversion circuit, a filtering inductor, an EMC (Electro Magnetic Compatibility) filtering circuit, a sampling circuit, a power switch pipe driving circuit and a DSP (Digital Signal Processor), wherein the DSP consists of a PLL (Phase Locked Loop) control module, a voltage outer ring PI control module, a current inner ring PI feedforward control module and a sinusoidal PWM (Pulse-Width Modulation) wave sending control module, and an input signal of the sinusoidal PWM wave sending control module of the DSP further includes a current inner ring current given amount Ig. The invention further provides a reactive power control method of the single-phase photovoltaic inverter. The method not only can be used for judging whether the voltage Uac of a power grid is larger than zero, and comparing the absolute value of a PWM wave sending control input modulation wave Upwm with a given triangular carrier wave Uc, but also can be used for judging whether the given current inner ring current amount Ig is larger than zero. Not only can the conduction loss of a power switching tube be reduced, and the conversion efficiency of the inverter is improved, but also the current waveform can be continuous, an output harmonic wave is reduced, and the pollution on a harmonic wave of a power grid is reduced.

The invention discloses a non-isolation bidirectional high-gain DC/DC converter and a frequency conversion control method, and belongs to non-isolation high-frequency power conversion in power electronic field. The non-isolation bidirectional high-gain DC/DC converter disclosed by the invention comprises a main circuit and a control circuit, wherein the main circuit mainly consists of a low-voltage end V<L>, a high-voltage end V<H>, two inductors (L<1>, L<2>), n+2 MOS transistors (S<1>, S<2>, Q<1>-Q<n>) and n capacitors (C<1>-C<n>), wherein n is cascading quantity. The invention also discloses the frequency conversion control method for the non-isolation bidirectional high-gain DC/DC converter. The switching frequency of the MOS transistors is regulated by the frequency conversion control method, so that current pulsation and ring current loss are reduced of each MOS transistor in the main circuit of the converter under the premise that realization of soft switching is ensured. The non-isolation bidirectional high-gain DC/DC converter and the frequency conversion control method can be widely applicable to storage battery energy storage or a new energy automobile motor driving system.

The invention discloses a PWM rectifier control method based on model prediction and voltage square control. The square of the output direct-current side voltage is controlled to serve as the given inner ring active current, the quick response of a controller is ensured through the linear relation between the square of the voltage and the active current, and the anti-disturbance capacity of a rectifier is further enhanced through the model prediction control of the inner ring current. The cost function of model prediction is quickly obtained through the finite set on-off state so that the control method can be easily achieved on a digital controller. The dynamic response and the anti-disturbance capacity of the whole controller can be enhanced through the selection of the weighting coefficient in the cost function and the coordination with the pre-charging soft start strategy. By means of the double-closed-loop control method, the quick response and the high anti-disturbance capacity for load disturbance are achieved while it is ensured that the alternating-current side of the rectifier reaches the unit power factor and the current total harmonic distortion rate reaches the national standard requirement. By means of the double-closed-loop control method combined with the voltage square model prediction control, the control over the unit power factor and the disturbance resistance of the three-phase voltage type PWM rectifier is achieved, and great reference value is provided for engineering.

The invention provides a d-q axis parameter identification method for a grid-connected inverter of a photovoltaic power generation system. The d-q axis parameter identification method includes: an inverter control reference value Udc-ref and Qref jump are arranged on the grid-connected inverter of the photovoltaic power generation system, or a three-phase short circuit fault is manufactured on the side of a power grid so as to collect disturbance data required by parameter identification; d axis parameters of the grid-connected converter are calculated according to the collected data, and the d axis parameters comprise filter inductance, d axis inner ring current control ring proportionality coefficients, inner ring current control ring integral coefficients, outer ring active power control ring proportionality coefficients and outer ring active power control ring integral coefficients; and a filter inductance parameter is fixed to be a d axis identification result, q axis parameters of the grid-connected inverter are calculated according to the collected data, and the q axis parameters comprise q axis inner ring current control ring proportionality coefficients, inner ring current control ring integral coefficients, outer ring reactive power control ring proportionality coefficients and outer ring active power control ring integral coefficients. The d-q axis parameter identification method for the grid-connected inverter of the photovoltaic power generation system reduces order and identification difficulty of a model to be recognized and improves identification accuracy.

The invention discloses a modular multi-level converter inter-phase power unbalance control method. A modular multi-level converter (MMC) system comprises three ends, that is, submodules having photovoltaic cell panels respectively, a DC power grid and a three-phase AC power grid. The control method comprises the following steps: obtaining output power of each submodule; carrying out three-end power control according to a system power allocation instruction; and when output power instructions of the three-phase cell panels are not equal, carrying out power tracking by injecting bridge arm zero-sequence ring current into each phase of bridge arm according to unbalance conditions, so that a three-phase system is allowed to operate stably according to a preset power instruction and balance of output power of the three-phase AC power grid is ensured.

The invention provides a battery management method, a battery management device and equipment powered by a battery, and relates to the technical field of communication. Harmful effects caused by bias current and ring current can be controlled effectively, and the bias current and the ring current are generated when batteries or battery packs of different capacities and materials are directly utilized in parallel. The method is capable of managing two or more than two parallel batteries or battery packs in a circuit, and a parallel branch is formed by the branch where each parallel battery or battery pack is located. The method comprises: whether a current value of a target parallel branch is larger than a preset current value or not is detected; when the detected current value of the target parallel branch is larger than the preset current value, the current value of the target parallel branch is adjusted to be smaller than or equal to the preset current value. The battery management method is used for management of parallel batteries.

The invention discloses an MMC ring current control method of a bridge-arm single sensor. The method comprises the following steps that (1) the resistance-inductive voltage, AC output current and DC bus current of bridge arms are collected, and the bridge-arm output voltage and the bridge-arm current are obtained; (2) according to a frequency doubled ring current inhibition principle based on energy analysis of the bridge arm, the number of sub-modules needed by each bridge arm is obtained; (3) according to the bridge-arm output voltage, the bridge-arm current and a sub-module driving signal of the last moment, capacitance-voltages of the sub-models in the next moment is predicted; and (4) the capacitance-voltage predicted values are ordered to predict a sub-module driving signal of the next moment, and the sub-module driving signal of the next moment is distributed to corresponding sub-modules. A single voltage sensor is used for the bridge arms, it is not required to detect the capacitance-voltage of each sub-module, the cost of voltage sensors and part of current sensors can be omitted, the complexity of a hardware circuit and a controller is reduced, and the method can be used to process a large-scale MMC system.

The invention puts forward a modular multilevel converter (MMC) hierarchical control method. On the basis of the existing voltage-current and sub module control method, a current injection ring current suppression structure, a sub module capacitive voltage ripple suppression structure and a predicted composite voltage frequency and amplitude recovery control method are superimposed. Hierarchical control is divided into inner-ring basic control and outer-ring optimized control. The hierarchical control method is applicable to half-bridge sub module, full-bridge sub module and mixed-bridge sub module multilevel circuits. Inner-ring control comprises a voltage and current loop control structure, a sub module capacitive voltage ripple control structure, a ring current injection suppression control structure, and the like. Outer-ring control comprises a droop control structure, a predictive composite control structure, and the like. Ring current injection suppression control, sub module capacitive voltage ripple control and predictive composite control methods are put forward by the invention. The control method of the invention can help improve the stability of a system under different load conditions, improve the quality of output voltage and power of a DC transmission system, reduce the investment cost of a modular multilevel transmission system, and improve the anti-interference ability and rapid response ability of a transmission system.

The invention discloses a parallel structure of a voltage source type PWM (Pulse Width Modulation) rectifier and a control method of the rectifier, belonging to the technical field of power electrical application. A topology circuit structure of the voltage source type PWM (Pulse Width Modulation) rectifier includes a parallel structure of a single-phase voltage source type PWM (Pulse Width Modulation) rectifier and a parallel structure of a three-phase voltage source type PWM (Pulse Width Modulation) rectifier. The control method is a vector control technology based on power system voltage orientation, which comprises the following steps of: by use of voltage outer ring and current inner ring control way, separating out an outer ring voltage regulator of a control circuit of the parallelvoltage source type PWM (Pulse Width Modulation) rectifier to form a common uniform voltage regulator, outputting a unique outer ring control voltage, simplifying a control policy into single closed ring current control to solve consistency problem of energy flow direction of the parallel voltage source type PWM(Pulse Width Modulation) rectifier so as to avoid generation of ring current and to provide technical supports for high power, modularization and large-scale application of the multi-module parallel connection of the voltage source type PWM (Pulse Width Modulation)rectifier.

The invention relates to a method for controlling parallel running of a micro-grid multi-inverter combination on the basis of capacitor voltage differentiation. The method is suitable for a micro-grid multi-inverter parallel control system consisting of a plurality of inverters connected to one another in parallel. Filtering capacitor voltage is differentiated to obtain filtering capacitor current, the filtering capacitor current can be acquired without the aid of a current transformer, and the designing amount of a hardware circuit is reduced; alternating quantity serves as the filtering capacitor voltage and filtering inductor current during power computing, and the outputting power of the inverters is reflected accurately; virtual complex impedance is guided in droop control, the output impedance of the inverters is ohmic, the inverters are suitable for a low-voltage micro-grid, and ring current among the inverters which are connected to one another in parallel is greatly reduced; and a dead-beat control method is used in current inner ring control, the filtering inductor current is controlled, the robustness of the system is high, the stability of the inverters which are connected to one another is high, and dynamic response is fast.

The invention discloses a fault detecting method for side windings of a three-phase three-winding transformer. First, three-phase winding voltage and three-phase winding currents of two Y sides of the transformer are measured, the ring current of a delta side of the transformer is measured, and the zero-sequence voltage and the zero-sequence current of the two Y sides of the transformer are respectively calculated; the zero-sequence voltage and the zero-sequence current of the two Y sides of the transformer are converted to the delta side of the transformer according to a corresponding transformer ratio, the leakage inductance corresponding to mutual leakage flux of the two Y sides of the transformer is converted to the leakage inductance of the delta side according to the square of the transformer ratio, the leakage inductance corresponding to the mutual leakage flux of the delta side and the two Y sides of the transformer is converted to the leakage inductance of the delta side according to the square of the transformer ratio, and the resistance of the two Y sides of the transformer is converted to the resistance of the delta side according to the square of the transformer ratio; the leakage inductance corresponding to the natural leakage flux of the two Y sides of the transformer is calculated and converted to the leakage inductance L'2 and leakage inductance L'3 of the delta side and the leakage inductance L1of the delta side self of the transformer; L1, L'2, L'3 and setting threshold values L1 set, L2 set and L3 set form fault detecting criterions for the side windings of the three-phase three-winding transformer.

The invention discloses a current critical continuous unified control method for a bidirectional DC-DC converter, relates to a current critical continuous unified control method for a dual-active bridge bidirectional DC-DC converter, and belongs to the field of power electronics. According to the control method disclosed by the invention, voltages on a primary side and a secondary side of a transformer and a phase difference between the voltages are controlled to make the converter work in a transformer current critical continuous mode and reduce the ring current and conduction loss of the converter. In addition, a transformer current can be enabled to be in a critical continuous mode through a boundary condition and a control condition, so that the reactive loss of a circuit is reduced, the current stress of a switching tube and the ring current loss of the converter are reduced, and the efficiency and reliability of the converter can be improved. The method further can greatly lower the complexity of a control unit and realize real-time control. The method can be applied to high-frequency isolation switching power supplies.

The invention provides a high-pressure sealing circulatory imitating wax deposition device for wax deposition imitation in long petroleum pipeline. It comprises a sealing kettle (26) which has an oil inlet (15) and an oil outlet (27), an electric stirrer (23) inserted in kettle (26), a temperature-control and a detector. The temperature-control has an inner heater which is fixed on the stirrer (23) and inserted in the kettle (26), a clamping sheath (4) which covers the inner container (6), a heat-insulating layer (3) and an outer cover (2). The detector comprises a piezometer (10) which is inserted in the kettle (26) through the kettle cover (7), a plurality of temperature sensor (21-2) in the kettle (26), a temperature sensor slideway (14), a plurality of temperature sensor drive pipe (20) which is through the outer cover (2), heat-insulating layer (3), clamping sheath (4) and close to the outer wall of inner container (6). Said simulator has small structure, volume, little apparatuses, large experiment space of oil sample, while the equivalent sheared intensity of oil sample equals the intensity of on-site oil of channel in the simulating experiment that the geometrical and dynamical condition is close to the on-site reality. The experiment has real simulating course, accurate data, and lower cost.

The invention discloses a control method of a railway power regulator based on a half-bridge structure. The railway power regulator based on the half-bridge structure is composed of two half-bridge arms, and the two half-bridge arms are connected with each other by two capacitors. Since the voltage at the DC side is powered by two series capacitors, the problem of voltage sharing exists. In orderto realize voltage sharing at the DC side, a voltage sharing PI regulator is used for controlling the deviation of the two capacitor voltages, and the offset output by the voltage sharing regulator directly influences the charging and discharging current of the two capacitors, thereby reducing the deviation to 0. In order to keep the voltage at the DC side stable, the voltage external ring at theDC side uses a PI controller to regulate the output value, and the output value is respectively multiplied by the synchronizing signals of the two power supply arms, and superposed by the harmonic and negative sequence compensating current reference signal obtained by computation according to the VV traction system negative sequence and the harmonic compensation principle, thereby obtaining the current reference signal of the two half-bridge converters. In order to realize quick tracking of internal ring current, a hysteresis control method is used for the output currents of the two converters, so that the currents from the output ends of the two converters track the reference compensating signal, thereby realizing negative sequence and harmonic compensation.