787 results about "Level converter" patented technology

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 invention discloses a direct-current power transmission receiving end and a direct-current power transmission system. The direct-current power transmission receiving end comprises an inverter circuit and a receiving end transformer; the inverter circuit comprises a hybrid power grid commutation converter and a modular multi-level converter; a direct current first end of the hybrid power grid commutation converter is used for connecting a direct current power transmission line, a direct current second end of the hybrid power grid commutation converter is connected with a direct current first end of the modular multilevel converter, and an alternating current end of the hybrid power grid commutation converter is connected with a receiving end alternating current bus through a corresponding receiving end transformer; the direct current second end of the modular multilevel converter is grounded, and the alternating current end of the modular multilevel converter is connected with the receiving end alternating current bus through the corresponding receiving end transformer. In the embodiment of the invention, the hybrid power grid commutation converter and the modular multi-level converter which are connected in series are used at the direct-current transmission receiving end, so that the direct-current transmission receiving end has direct-current side fault ride-through capability and alternating-current side fault ride-through capability.

The invention discloses a clamping type multi-level converter and a control method, relates to the field of clamping, and aims to enable the voltage of a flying capacitor in the multi-level converter to be 1 / (N-1), 2 / (N-1)... (N-2) / (N-1) times of Vbus voltage (bus voltage) even if the voltage of the flying capacitor is in a steady state. The number of the clamping units is the same as that of the flying capacitors, and each flying capacitor is connected in series with the equivalent capacitors of the corresponding number of bus capacitors through the corresponding clamping unit when the multi-level converter switching tube is closed, so that each flying capacitor is clamped through the voltage of the corresponding number of equivalent bus capacitors; and the voltage of the flying capacitor in the multi-level converter can be ensured to be in a steady state without closed-loop control.

The invention discloses a neutral-point potential balancing method and device for a three-level converter suitable for an unbalanced load, and belongs to the technical field of three-level converter control, and the method comprises the steps: 1, carrying out the positive and negative sequence separation of a sampling signal, and achieving the output of a three-phase balanced voltage; step 2, calculating an ideal zero-sequence component needing to be added in the modulated wave; step 3, analyzing the adjustment capability of adding the ideal zero-sequence component, and if the adjustment capability is satisfied, executing step 4; if not, skipping to step 7; 4, correcting a modulation wave symbol in the ideal zero-sequence component; 5, designing a potential regulator of the zero-sequence voltage based on the corrected modulation wave symbol; 6, performing amplitude limiting on the sum of the zero-sequence component generated by the potential regulator and the ideal zero-sequence component; step 7, carrying out midpoint balance by using an external balance circuit; and the three-level converter stops running, and the process is ended. According to the invention, neutral-point potential balance of the three-level converter is realized by adding the zero-sequence component in modulation.

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.

The invention relates to the technical field of power electronics, in particular to a multi-level converter midpoint voltage dynamic balance control method, which comprises the following steps: acquiring positive bus voltage and negative bus voltage, and calculating deviation voltage of a DC side midpoint based on the positive bus voltage and the negative bus voltage; on the basis of the positive bus voltage, the negative bus voltage and the calculated deviation voltage of the direct current side midpoint, the duty ratio in the current switching period is calculated by combining the obtained balance bridge current, the obtained balance bridge inductance value and the switching period; determining the duty ratio of upper and lower tubes of the balance bridge according to the comparison result of the deviation voltage and preset positive and negative threshold values; and carrying out carrier wave comparison based on the determined duty ratio of the upper and lower tubes of the balance bridge, generating a PWM signal and driving the upper and lower tubes of the balance bridge. According to the invention, the requirements of high responsiveness and high precision of the multi-level converter on the neutral-point voltage balance performance under the dynamic operation condition can be met.

A multiple input converter for outputting power from AC power or a battery to positive and negative direct current (DC) buses is provided. The multiple input converter includes at least one bridge arm unit and a bidirectional DC-DC conversion unit. The bridge arm unit corresponds to one phase of the alternating current (AC) power and includes an upper and lower bridge arms that can independently form a two-level converter. In a battery mode, the upper and lower bridge arms discharge power from the rechargeable battery to the positive and negative DC buses, and the bidirectional DC-DC conversion unit discharges power from the rechargeable battery to the positive and negative DC buses or balances voltages of the positive and negative DC buses. In a mains mode, the bridge arm units are connected to the AC power. The bidirectional DC-DC conversion unit determine whether to charge or discharge according to load conditions.

In an example, a level shifter includes a low side having first and second inputs. The level shifter also includes a high side, where the high side has a latch having first and second terminals. The high side also includes a current comparator including first and second current mirrors. The high side includes isolation circuitry including first and second transistors, in which the first transistor has a first control terminal, the second transistor has a second control terminal, the first transistor is coupled between the first terminal and the first current mirror, the second transistor is coupled between the second terminal and the second current mirror, the first control terminal is coupled to the second current mirror, and the second control terminal is coupled to the first current mirror.

The invention discloses a low-cost charging pile topology for a fast charging-slow discharging scene of an electric vehicle and a modulation strategy of the low-cost charging pile topology. According to the low-cost charging pile topology, a group of half-bridge type shunt diodes are connected in parallel to each phase of main bridge arm of a traditional T-shaped three-level converter. In the discharging mode, the charging pile is consistent with a traditional T-type three-level operation state, and works in a slow-release scene with rated power and below. In the charging mode, the charging pile continuously shunts the main bridge arm power device by using the additionally arranged shunting diode, so that the current stress and thermal stress of the main bridge arm power device are reduced; and through a self-adaptive modulation strategy of three-level / two-level modulation mode switching, the loss distribution of a power device is optimized, the active power output capability of the charging pile in a charging mode is improved, the fast charging operation of the charging pile with over-rated power is realized, the equipment capacity utilization rate of the charging pile is fully excavated, and the method has remarkable engineering application value.

The invention relates to the technical field of parallel three-level converter control, and provides a parallel three-level converter model prediction control method and system, and the method comprises the steps: enabling a parallel three-level converter to be modeled as a series connection of an equivalent voltage source and an equivalent filter inductor according to the Thevenin theorem, enabling the parallel three-level converter to be equivalent to a five-level converter, and enabling the parallel three-level converter to be connected in parallel; a three-layer optimization control strategy is adopted; in the first layer, a candidate vector closest to a reference voltage vector is selected as an optimal five-level basic vector so as to track a parallel total output current; in the second layer, a redundant five-level voltage vector is selected to balance the neutral-point voltage; and in the third layer, selecting the candidate switching state which enables the circulating current suppression value function to be the minimum as the optimal redundant three-level switching state so as to suppress the circulating current. The method can effectively reduce output current harmonics under low switching frequency, and balance of neutral-point voltage and effective suppression of circulating current are realized to ensure safe and stable operation of a parallel converter system.

A level shifter includes: a low voltage domain configured to output non-overlapping first and second current pulses based on opposite edges of a logic input signal; and a high voltage domain comprising a latch and a current mirror circuit configured to mirror the non-overlapping first and second current pulses such that the latch is set when the first current pulse is active and reset when the second current pulse is active. The current mirror circuit includes a first mirroring path for the first current pulse and a second mirroring path for the second current pulse. The level shifter has a common mode slew current that is added to the non-overlapping first and second current pulses. The first mirroring path and the second mirroring path are cross-coupled such that the common mode slew current is reduced or cancelled before the non-overlapping first and second current pulses are input to the latch.

The invention relates to the technical field of modular multilevel converters, and provides an MMC fault diagnosis method, system and device based on a sorting voltage-sharing algorithm. Comprising the steps that according to measurement data of the modular multilevel converter, a theoretical value and an actual value of bridge arm voltage of the modular multilevel converter are obtained through calculation, the theoretical value and the actual value are compared with a first alarm threshold value, and a corresponding bridge arm fault and a fault type are determined; calculating the number of fault sub-modules according to the bridge arm voltage actual value and the bridge arm voltage theoretical value; judging the switching number of the fault bridge arm sub-modules, and controlling and adjusting the bridge arm sub-modules to be switched on according to the fault type and the number of the fault sub-modules; and calculating a capacitor voltage minimum difference value, comparing the capacitor voltage minimum difference value with a second alarm threshold value, and determining a fault sub-module. According to the multi-tube fault diagnosis method, the problem that the fault positioning performance is poor under the light load working condition is solved, and the sub-module positioning performance in the full power range is improved.

The invention provides a bidirectional level converter and electronic equipment, and relates to the technical field of analog integrated circuits, the bidirectional level converter comprises a first port, a second port and a conversion circuit arranged between the first port and the second port; the first port comprises a first input / output port and a first reference level port; the second port comprises a second input / output port and a second reference level port; the conversion circuit comprises a first Schmidt comparator, a clamping circuit, a pull-up module, a pull-down module and a second Schmidt compartment.The bidirectional level converter and the electronic equipment have the advantages that under the condition that an input signal is converted from a high signal to a low signal, driving of an input stage does not need extremely high driving capacity, input and output are in an isolated state, and the conversion efficiency is improved; and the load size of the output stage has no influence on the driving capability of the input stage, so that the integrity of signals can be maintained, the system design is more flexible, and meanwhile, the circuit can adapt to more application scenes.

A level shifter according to an embodiment and a display device including the same are disclosed. A level shifter includes a first logic circuit configured to receive a mode selection signal of a first voltage level for selectively driving first and second light-emitting elements that emit light at different viewing angles of a pixel circuit from a timing controller and transmit the mode selection signal; and a second logic circuit configured to convert the mode selection signal of the first voltage level into a mode selection signal of a second voltage level higher than the first voltage level and output the converted mode selection signal of the second voltage level to the pixel circuit.

The invention relates to a three-level SVG multistage WARD equivalent modeling method based on an L / C constant admittance model. An ANPC type three-level converter model is an important part of various types of power electronic equipment, and is applied to scenes such as a three-level static var generator (SVG) and the like. In small-step offline simulation, an existing simulation modeling technology cannot consider precision and efficiency at the same time. Aiming at the problem that the simulation speed is extremely low in an offline simulation platform, a three-level SVG electromagnetic transient simulation acceleration model equivalent to a multi-stage nested fast simultaneous solution algorithm is provided based on a device Norton equivalent circuit. Firstly, an L / C equivalent constant admittance model is used for carrying out equivalent processing on a switching device, first-time WARD equivalence is carried out, then an equivalent circuit is connected with other transformer and filter inductance circuit parts, WARD equivalence is carried out again, and finally a Norton form equivalent circuit is formed.

A system may include a multi-level power converter comprising a power inductor and a plurality of switches and a controller configured to control the plurality of switches such that the multi-level power converter generates a regulated output voltage from an input voltage to the multi-level power converter, monitor an average inductor current through the power inductor, and operate the multi-level power converter in one of a continuous conduction mode and a discontinuous conduction mode based on the average inductor current.

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

A voltage source multi-level converter topology and a control method thereof. The voltage source multi-level converter topology includes two groups of half-bridge circuits, two groups of flying capacitors and a plurality of switches. Each group of half-bridge circuits include two direct-current connection ends, and outputs of the two groups of half-bridge circuits are both connected, through a switch, to the two groups of flying capacitors that are in series. A neutral point of a connection between the two groups of flying capacitors is connected to an alternating-current end through two switches that are in reverse series, and an overall positive electrode and an overall negative electrode of the two groups of flying capacitors that are in series are respectively connected to the alternating-current end through switches.

Embodiments disclose a level shifter including a logic unit configured to receive timing data and channel data and output an edge signal and a channel signal at a time point defined in the timing data, and a channel selection unit configured to select at least one channel from among a plurality of connected channels according to the channel signal and transmit the edge signal, and a display device including the same.

The invention discloses a display device, a control method thereof and display equipment, and relates to the field of display, the display device comprises a time schedule controller, a power management module, a display panel and a plurality of level converters, the display panel comprises a plurality of pixel areas, and each pixel area comprises at least one pixel row; the time sequence controller is connected with the time sequence input end of each level translator, the power supply management module is connected with the voltage input end of each level translator, each pixel region is connected with the time sequence output end of one level translator, and different pixel regions are connected with different level translators; the level converter is used for receiving a time sequence reference signal sent by the time sequence controller and is also used for receiving a target grid high-level voltage sent by the power supply management module; the level shifter is further configured to generate a timing control signal based on the target gate high-level voltage and a timing reference signal. The problem that the brightness display of the display panel is not uniform is solved.

The invention provides a hybrid modular multi-level grid-connected converter based on intensive redundant module multi-terminal sharing. The hybrid modular multi-level grid-connected converter comprises a three-phase circuit topology; the three-phase circuit topology comprises three same single-phase topologies, and each single-phase topology comprises an upper bridge arm, an upper bridge arm inductor, an upper bridge arm switch, a middle module, an alternating current bridge arm, a lower bridge arm, a lower bridge arm inductor and a lower bridge arm switch; the intermediate module comprises a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a fifth switch tube, a sixth switch tube and a direct current capacitor. According to the invention, by introducing the intermediate module, the fault-tolerant capability is provided when the upper and lower bridge arm sub-modules and the AC bridge arm sub-module have faults. Compared with a traditional redundant module configuration mode, the topology has the advantages that the utilization rate of the redundant module is greatly improved, and the operation reliability of the multi-level converter is improved.

The invention discloses a three-level converter two-dimensional optimization model prediction control method and device. The method comprises the following steps: calculating a reference voltage vector and a phase angle of an inverter at a moment k through a dead-beat principle; the method comprises the following steps: dividing a voltage vector region of a three-level converter into six large sectors based on a two-dimensional optimization principle, and dividing each large sector into six small sectors; taking the optimal voltage vectors corresponding to the small and medium sectors in each large sector as preparatory optimal voltage vectors, and making a preparatory optimal voltage vector corresponding table of each sector; selecting a preparatory optimal voltage vector corresponding to the reference voltage vector at the k moment by using the preparatory optimal voltage vector corresponding table of each sector; determining an optimal voltage vector according to the prepared optimal voltage vector and the neutral-point voltage; according to the invention, on the premise of realizing neutral-point voltage balance and stable operation of the three-level converter, current ripples and calculation burden can be reduced.

Disclosed is a test device to test the operation of an MMC by fabricating only one or several SMs constituting the MMC testing under real-time operating conditions. The test device for a modular multi-level converter (MMC) includes a simulation model of an MMC having at least one arm to which sub modules (SMs) are serially connected, at least one test target SM among the serially connected SMs being replaced with a dependent voltage source; an arm current simulation circuit including an equivalent SM that implements the test target SM as actual physical hardware and an inverter that supplies current to the equivalent SM; and a control unit configured to control the arm current simulation circuit to correspond to an operation of the simulation model and set a voltage corresponding to a charge / discharge voltage of the equivalent SM of the arm current simulation circuit to the dependent voltage source.

The invention provides a resistance voltage division control redundancy power supply circuit for a multi-level converter power sub-module, and relates to the technical field of power supply of the multi-level converter power sub-module. The resistor voltage division control redundancy power supply circuit comprises n voltage division resistors which are connected in series and are connected with a high-voltage direct-current capacitor in parallel; one end of the first through-current unit is connected with a connection point of the (k-1) th divider resistor and the kth divider resistor; one end of the second through-flow unit is connected with a connection point of the (j-1) th divider resistor and the jth divider resistor, and the other end of the second through-flow unit is connected with an energy storage capacitor of the bypass switch; one end of the resistance voltage division control branch is connected with one end of the first through-current unit, and the other end is connected with the negative electrode of the high-voltage direct-current capacitor; and two ends of the redundant power supply and energy taking module are respectively connected with the other end of the first through-current unit and the negative electrode of the high-voltage direct-current capacitor. In the low-voltage pre-charging stage of the multi-level converter power sub-module, starting of redundant power supply is achieved, black module faults are avoided, and the system reliability is improved.

The invention discloses a single-stage interconnection converter port power distribution method based on a multilayer space vector modulation strategy. The method comprises the following steps: firstly, obtaining a single-stage interconnection converter alternating current side reference voltage vector through an energy management strategy, a power control loop and a current and voltage double closed loop of a hybrid alternating current and direct current micro-grid; then, the single-stage interconnection converter is subjected to equivalent decoupling modeling to form four virtual two-level converters, a four-layer space vector diagram is obtained, scaling factors for decomposing reference voltage vectors are calculated according to given reference power, and therefore the two reference voltage vectors on the alternating current side are decomposed into four independent voltage vectors; and synthesizing the four voltage vectors in a four-layer space vector diagram to obtain the duty ratio of each phase of the four two-level converters so as to obtain the switching sequence of the single-stage interconnection converter.

The invention discloses a fault current analysis method and system for a multi-terminal flexible DC circuit, and the method comprises the steps: analyzing fault current data when the DC side of a modular multilevel converter is short-circuited, and obtaining time sequence segmentation rule data; performing equivalent processing on the modular multilevel converter based on the segmentation rule data to obtain an equivalent circuit model comprising an RLC series circuit and a time-varying current source; constructing a second-order differential equation for describing the fault current according to the equivalent circuit model, and solving the second-order differential equation to obtain a fault current expression containing dynamic alternating current feed-in; constructing a fault equivalent network of the multi-terminal flexible DC circuit; and constructing a state-space equation of the fault equivalent network based on a branch current method and the fault current expression, and solving the state-space equation to obtain fault current data of the multi-terminal flexible DC circuit. According to the method, the accuracy of fault analysis is improved.

The invention belongs to the technical field of grid-connected control, and particularly relates to a grid-following type and grid-constructing type smooth switching control method for a three-level converter based on LC filtering, and the method comprises the steps: collecting the grid-side voltage uabc of the converter and the current iabc at the outlet of the converter in real time, and obtaining the active output power P and reactive power Q of the converter; constructing a control loop for smooth switching of phase angles of active control loops and phase-locked loops of the following network type and the construction network type according to the topological structures and the mathematical models of the following network type and the construction network type converters; and constructing a following network type and constructing network type d and q axis current reference value smooth switching control loop. Compared with the prior art, the method has higher accuracy and flexibility, power and frequency fluctuation in the converter switching process can be better restrained, the grid-connected stability is improved, and safe and stable operation of the converter under the condition that the power grid strength is greatly changed is achieved.

The invention discloses an unbalanced load compensation method for a three-phase four-wire three-level converter. According to the method, a three-phase four-wire system three-level converter bridge arm voltage mathematical model is established based on sine carrier in-phase laminated modulation, and harmonic content analysis is completed; an SOGI-pro module is established (an error integration link is added at the input front end of a D axis of an SOGI filter, and D and Q axis second-order band-pass filters are transformed into third-order band-pass filters), so that the positive and negative sequence separation precision of three-phase unbalanced load voltage is improved. According to the method, the order of the SOGI filter is improved by reasonably designing a closed-loop transfer function, and the filtering effect of the SOGI filter in high and low frequency bands is enhanced. And a sequence-dividing imbalance compensation control loop is designed based on the three-sequence dq0 coordinate system, so that zero-static-error tracking of a positive-sequence fundamental component and powerful suppression of negative-sequence and zero-sequence imbalance components are realized. According to the invention, the accuracy of traditional positive and negative sequence separation is improved, so that the unbalanced load compensation effect under sequence separation control can be improved.

The invention relates to the technical field of converter control, and provides a loss optimization control method for a modular multilevel converter and related equipment, and the method comprises the steps: solving an expression of the average conduction loss and an expression of the average switching loss of a target modular multilevel converter; according to the expression, the positive correlation between the loss and the absolute average value of the bridge arm current is obtained through analysis, and the expression of the absolute average value of the bridge arm current is obtained; according to the positive correlation, loss optimization is equivalent to optimization of the absolute average value of the bridge arm current, and the optimal value range of the initial phase angle when the absolute average value of the bridge arm current is minimized is analyzed; according to the optimal value range of the initial phase angle, calculating an optimal initial phase angle and an optimal double frequency circulation component when the absolute average value of the bridge arm current is minimized; and controlling the target modular multi-level converter according to the optimal double-frequency circulation component and the optimal initial phase angle. According to the method, the optimization precision can be improved while loss optimization is realized.

A level shifter or a display device comprising a level shifter includes a scan channel circuit generating a scan start signal for a plurality of subpixels according to a first input signal, a charge pump circuit generating a high-potential emission voltage using circuit power of a host system, and an emission channel circuit controlling an emission start signal according to a second input signal with a change in the circuit power reflected.