42results about How to "Reduce circulating current" patented technology

This document discusses, among other things, a stator with transposition between the windings or coils. The coils are free from transposition to increase the fill factor of the stator slots. The transposition at the end connections between an inner coil and an outer coil provide transposition to reduce circulating current loss. The increased fill factor reduces further current losses. Such a stator is used in a dual rotor, permanent magnet machine, for example, in a compressor pump, wind turbine gearbox, wind turbine rotor.

Disclosed is a hybrid dc-dc converter. The hybrid dc-dc converter includes: a pair of transformers configured to magnetically couple a primary side to a secondary side, a full-bridge converter including four switches constituting a full-bridge inverter circuit and a first transformer, and an LLC resonant converter including a resonant inductor, a resonant capacitor, and a second transformer, which constitute an LLC resonant circuit, wherein an output of the full-bridge converter and an output of the LLC resonant converter are connected to each other in series at the secondary side.

Embodiments of the present invention provide novel techniques for using multiple 18-pulse rectifier circuits in parallel. In particular, each rectifier circuit may include an autotransformer having 15 inductors coupled in series, joined by 15 nodes interposed between pairs of the inductors. The inductors may be represented as a hexagon in which alternating sides of the hexagon have two and three inductors, respectively. Each rectifier circuit may also include three inputs for three-phase AC power coupled to alternating vertices of the hexagonal representation and nine outputs for AC power coupled between each node that is not a vertex of the hexagonal representation and a respective diode bridge. Outputs of the diode bridges for the rectifier circuits may be coupled to a DC bus. In addition, a means for reducing circulating current between the parallel rectifier circuits and for promoting load sharing between the parallel rectifier circuits is also provided.

The invention discloses a track control method of a double-transformer series resonance double-active-bridge DC-DC converter topology. The method comprises the steps of firstly designing control tracks of a primary side outer phase shift angle and a secondary side inner phase shift angle of a converter; through the sampling circuit, the high-voltage side voltage and the low-voltage side voltage ofthe converter are sampled. The original secondary side outer phase shift angle and the secondary side inner phase shift angle of a current control variable are calculated through a digital control circuit. According to the control track, the original secondary side outer phase shift angle and the secondary side inner phase shift angle are controlled to move along the track all the time such thatsoft switching conditions and minimum loop current control are guaranteed; the control quantity is output through a drive circuit, and then the converter is controlled to operate. According to the method, the closed-loop control follows a control track based on fundamental wave analysis (FCA) by adjusting a phase shift angle and a high-level duty ratio such that the control flexibility can be greatly improved, the circulating current can be remarkably reduced, the efficiency can be improved, and all soft switches in a full-load range are ensured to be realized.

The present disclosure relates to an LC snubber circuit for a switching converter, wherein the switching converter includes an inductor and a switching device connected in series. The LC snubber circuit can include a first snubber diode, a snubber capacitor, a second snubber diode, and a snubber transformer having a primary winding and a secondary winding. The secondary winding of the snubber transformer is connected to an output of the switching converter.

The invention provides a multi-mode control method of an active clamp fly-back converter. In the fly-back converter, a controller realizes mode switching among a lagging edge non-complementary mode, aleading edge non-complementary mode and a leading edge non-complementary Burst mode of two driving signals after detecting a feedback voltage and comparing the feedback voltage with a set mode switching threshold voltage. According to the invention, the lagging edge non-complementary mode is adopted to reduce the circulating current of the converter, the leading edge non-complementary mode is adopted instead of a common fly-back mode to improve the light-load efficiency, and the leading edge non-complementary burst mode is adopted under the condition of no load in order to limit the magnitudeof the primary peak current in the burst mode, avoid audio noise and achieve low no-load power consumption.

The invention discloses a non-master / slave self-current-sharing grid-connected parallel uninterrupted power supply system and a power supply method thereof, and belongs to the technical field of power electronics. The system mainly comprises two or more parallel same uninterrupted power supply system units, wherein each uninterrupted power supply system unit comprises four single-phase full-bridge converters (H1-H4), three industrial frequency inductors (LS, L1, L2), a high frequency inductor (L), a direct current filter capacitor (C1), an alternating current filter capacitor (C2), an isolation transformer (T), two bidirectional thyristors (K1 and K2), an air switch (B) and a storage battery (VB); the input side of each uninterrupted power supply system unit is connected with the power grid through the air switch (B); and various uninterrupted power supply system units pass through the second and third industrial frequency inductors (L1 and L2) and the alternating current filter capacitor (C2), are connected in parallel and are connected with the power grid through the two bidirectional thyristors (K1 and K2). The bidirectional energy flow between the uninterrupted power supply and the power grid can be achieved, the power supply system is a green load relative to the power grid, and the efficiency and dynamic response speed of a parallel system are improved.

The invention provides a resonant converter based on ON / OFF control. The resonant converter comprises a primary side square wave inversion circuit I, a primary side LLC resonance circuit II, a transformer T, a secondary side full-bridge rectification circuit III and an output resistance load Ro. The resonant converter is characterized in that two auxiliary two-way switches are added to the primaryside square wave inverter circuit I; ON / OFF control is adopted for the auxiliary two-way switches, so that the resonant converter can work in a full-bridge LLC resonant converter mode and can also work in a half-bridge LLC resonant converter mode. Due to the topological structure of the resonant converter and the switching type control mode of the resonant converter, the switching frequency change range of the resonant converter is narrow, ultra-wide-range voltage gain adjustment is achieved, zero-voltage switching of a primary side switching tube is achieved, zero-current switching of a secondary side rectifying diode is achieved, and switching loss is reduced.

Embodiments of the present invention provide novel techniques for using multiple 18-pulse rectifier circuits in parallel. In particular, each rectifier circuit may include an autotransformer having 15 inductors coupled in series, joined by 15 nodes interposed between pairs of the inductors. The inductors may be represented as a hexagon in which alternating sides of the hexagon have two and three inductors, respectively. Each rectifier circuit may also include three inputs for three-phase AC power coupled to alternating vertices of the hexagonal representation and nine outputs for AC power coupled between each node that is not a vertex of the hexagonal representation and a respective diode bridge. Outputs of the diode bridges for the rectifier circuits may be coupled to a DC bus. In addition, a means for reducing circulating current between the parallel rectifier circuits and for promoting load sharing between the parallel rectifier circuits is also provided.

A method for calculating insertion indices for a phase leg of a DC to AC modular multilevel converter. Each phase leg includes two serially connected arms, wherein each arm includes a number of submodules, wherein each submodule can be in a bypass state or a voltage insert mode. The insertion index includes data representing the portion of available submodules that should be in the voltage insert mode. The method includes the steps of: calculating a desired arm voltage for an upper arm connected to the upper DC source common bar and a lower arm connected to the lower DC source common bar, obtaining values representing actual total arm voltages in the upper arm and lower arm, respectively, and calculating modulation indices for the upper and lower arm, respectively, using the respective desired arm voltage and the respective value representing the total actual arm voltage. A corresponding apparatus is also presented.

The invention provides a fixed-frequency control method of a full-bridge LLC resonant converter. The full-bridge LLC resonant converter is composed of a direct-current input source Vin, a primary sidesquare-wave generator I, a primary side LLC resonant circuit II, a transformer III, a secondary side full-bridge rectifying circuit IV, an output filter capacitor Co and an output resistance load Ro.The primary side square wave generator I is composed of a primary side first switch tube S1, a primary side second switch tube S2, a primary side third switch tube S3 and a primary side fourth switchtube S4. The primary side LLC resonance circuit II is composed of a resonance capacitor Cr, a resonance inductor Lr and an excitation inductor Lm. The primary side second switch tube S2 and the primary side fourth switch tube S4 are controlled through a pair of fixed-frequency complementary pulses, a duty ratio is 50%, and a switch frequency is equal to a series resonant frequency of the resonantcapacitor Cr and the resonant inductor Lr. Switch pulses of the primary side first switch tube S1 and the primary side third switch tube S3 are controlled through output voltage feedback, and duty ratios of the switch pulses of the primary side first switch tube S1 and the primary side third switch tube S3 are complementary.

Disclosed is a hybrid dc-dc converter. The hybrid dc-dc converter includes: a pair of transformers configured to magnetically couple a primary side to a secondary side, a full-bridge converter including four switches constituting a full-bridge inverter circuit and a first transformer, and an LLC resonant converter including a resonant inductor, a resonant capacitor, and a second transformer, which constitute an LLC resonant circuit, wherein an output of the full-bridge converter and an output of the LLC resonant converter are connected to each other in series at the secondary side.

The invention relates to a transformer continuous coil spiral transposition structure, a transposition method thereof and a manufacturing method thereof. The transformer continuous coil spiral transposition structure comprises a plurality of layers of wire cake groups which are axially arranged along a coil, wherein each layer of the wire cake group is formed by winding a plurality of wires whichare overlapped in the width direction; a special transposition structure is adopted between two adjacent layers of the wire cake groups at one half of the axial direction of the coil, or the special transposition structure is adopted between two adjacent layers of the wire cake groups at one quarter and three quarters of the axial direction of the coil, and a standard transposition structure is adopted between the other two adjacent layers of the wire cake groups; in the special transposition structure, the wires are divided into two groups, and the upper group of wires and the lower group ofwires are subjected to integral position exchange during transposition. According to the transformer continuous coil spiral transposition structure, the basic consistency of the resistance of each wire is ensured, the potential differences between the wires are greatly reduced, the circulating current is greatly reduced, the circulation loss is greatly reduced, the load loss during the operation of the transformer is further reduced, the temperature rise of the coil is reduced, and the service life of the insulating material is prolonged.

This document discusses, among other things, a stator with transposition between the windings or coils. The coils are free from transposition to increase the fill factor of the stator slots. The transposition at the end connections between an inner coil and an outer coil provide transposition to reduce circulating current loss. The increased fill factor reduces further current losses. Such a stator is used in a dual rotor, permanent magnet machine, for example, in a compressor pump, wind turbine gearbox, wind turbine rotor.

The disclosure discloses an LC snubber circuit for a switching converter, wherein the switching converter comprises an inductor and a switching device connected in series. The LC snubber circuit comprises a first snubber diode, a snubber capacitor, a second snubber diode, and a snubber transformer having a primary winding and a secondary winding. The secondary winding of the snubber transformer is connected to an output of the switching converter.

Techniques for using multiple 18-pulse rectifier circuits in parallel are described herein. In particular, each rectifier circuit may include an autotransformer having 15 inductors coupled in series, joined by 15 nodes interposed between pairs of the inductors. The inductors may be represented as a hexagon in which alternating sides of the hexagon have two and three inductors, respectively. Each rectifier circuit may also include three inputs for three-phase AC power coupled to alternating vertices of the hexagonal representation and nine outputs for AC power coupled between each node that is not a vertex of the hexagonal representation and a respective diode bridge. Outputs of the diode bridges for the rectifier circuits may be coupled to a DC bus. In addition, a means for reducing circulating current between the parallel rectifier circuits and for promoting load sharing between the parallel rectifier circuits is also provided.

The invention provides a communication battery module charging current-limiting strategy which comprises a battery management system integrating a main control module, a voltage temperature detectionmodule, a current detection module and a charging MOS (metal oxide semiconductor) transistor. The battery management system detects voltage, temperature and charging current of a battery pack in realtime and provides battery pack state information parameters for execution of the charging current-limiting strategy. The main control module starts and stops a charging current-limiting function according to whether there is a mains supply or not, performs related calculation and controls the charging MOS transistor to execute the charging current-limiting strategy under different battery pack states according to battery pack state information. The charging current-limiting strategy can effectively balance safety and charging efficiency of a communication battery module during charging, prolong service life of the battery module, ensure the battery module to be constantly in a standby power state within an allowed condition range and effectively lower circulating current when multiple battery modules are parallelly connected in use.

The invention provides a parallel connection power conditioning system which is provided with a filer for filtering cyclic currents, comprising an input terminal, a plurality of power conditioning devices and a load. The input terminal is used for receiving an input terminal power supply. Every power conditioning device comprises a DC-DC converter, a DC-AC transducer and the filter for filtering the cyclic currents. The DC-DC converter is used for receiving and transforming the input terminal power supply to form a steady DC voltage. The DC-AC transducer converts the steady DC voltage to an AC voltage. The filter is coupled to the DC-AC transducer for filtering noise in the AC voltage and the cyclic currents between the power conditioning devices and generating a filtration voltage. The load is connected to a plurality of power conditioning devices, wherein, a plurality of power conditioning devices are connected to the load in parallel.

The invention provides a control method based on an adaptive hybrid rectification multi-switch resonance LLC converter. The circuit is characterized in that the structure is simple, the number of required components is small under the condition that the same wide output voltage range is achieved, and the circuit comprises a capacitor unit, an inversion network, a resonance network, a high-frequency transformer, a rectification network and a pulse signal generation unit. According to the control method, fixed-frequency asymmetric pulse width (APWM) modulation is adopted, the switching frequency is fixed and equal to the resonant frequency, the conduction duty ratio of a switching tube is changed only through a pulse signal generation unit, smooth switching of a full-bridge inverter circuit, a half-bridge inverter circuit, a full-bridge inverter circuit and a voltage doubling rectifier circuit is achieved, and then ultra-wide output voltage regulation is achieved. And meanwhile, circulating current in the circuit is small, control is simple, and the size miniaturization of the transformer is facilitated.

The invention provides a novel PSPWM control method and system for an LLC resonant converter with a fixed-frequency variable structure. The LLC resonant converter adopting a full-bridge and half-bridge variable structure mixed working mode is arranged; the LLC resonant converter comprises a direct-current input source Vin, a primary side full-bridge / half-bridge hybrid inverter, an LLC resonant tank, an isolation transformer, a secondary side full-bridge rectifying circuit, an output filter capacitor Co and an output resistance load R which are connected in sequence; a first switching tube Q1,a second switching tube Q2, a third switching tube Q3 and a fourth switching tube Q4 in the primary side full-bridge / half-bridge hybrid inverter form a full-bridge inverter, and auxiliary switching tubes Q5 and Q6 are reversely connected in series between the midpoint between input split capacitors Cin1 and Cin2 and the midpoint of a full-bridge leading arm; and based on the switching-on and switching-off process of a primary side switching tube, three modes of conversion of a primary side working mode are completed, and the three modes correspond to a low voltage section, a medium voltage section and a high voltage section of an output voltage range respectively.

The present invention provides a power conversion circuit system in which a circulating current can be reduced by accurately detecting the circulating current, to thereby improve efficiency in power conversion. The power conversion circuit system includes a power conversion circuit composed of a primary conversion circuit having left and right arms and a secondary conversion circuit having left and right arms, and a control circuit for controlling switching of switching transistors in the primary and secondary conversion circuits. The control circuit detects the circulating current at at least one of timings lagged by pi / 2+phi / 2 from at least either a peak timing or a valley timing in a carrier counter where phi represents a difference in phase between the primary and secondary conversion circuits, and performs feedback control for reducing the detected circulating current to zero.

The invention discloses a stator of a flat wire motor, and a flat wire motor. The stator comprises a stator core and a stator winding, wherein each phase stator winding comprises N parallel branches; the star point connecting ends of all the parallel branches are led out from different winding grooves at a connecting side, and all the star point connecting ends, connected with a first star point connecting line and a second star point connecting line, in the three phase windings are led out from the winding grooves adjacent to the connecting side; the power supply leading-out ends of the same phase winding are led out from the same and / or adjacent winding grooves at the connection side and are electrically connected through power supply leading-out wires; and thus, the star point connecting ends and the power supply leading-out ends are distributed in a concentrated mode, a connecting side end winding structure is simplified, and the welding production difficulty of winding coils is lowered. In addition, the winding grooves for leading out the point connecting ends electrically connected with the first star point connecting line and the second star point connecting line are symmetrically distributed on the two opposite sides of the winding grooves for leading out the power supply leading-out ends, and the winding grooves for leading out the star point connecting ends are adjacent to the winding grooves for leading out the power supply leading-out ends, so ring current between branches is reduced.

The embodiment of the invention discloses an intelligent load regulation circuit and control system, and is used for solving the technical problems in the prior art that when a balance between supply and demand is realized through electric power energy storage, electric power energy storage scale development is limited by economic cost and function bottlenecks, many higher harmonics are generated when a reactive compensator is adopted, the device size is relatively large and the cost is relatively high. The intelligent load regulation control system provided by the invention includes an intelligent load regulation circuit, three-phase non-key loads, three-phase key loads, a voltage controller, a central processing unit and a phase locked loop; the intelligent load regulation circuit is in series connection with the three-phase non-key loads to form an intelligent load, and the intelligent load is in parallel connection with the three-phase key loads; the input end of the phase locked loop is connected with a power distribution network A phase, and the output end of the phase locked loop is connected with the central processing unit; the input end of the voltage controller is connected with three phases of the power distribution network, and the output end of the voltage controller is connected with the central processing unit; and the output end of the central processing unit is connected with the intelligent load regulation circuit.

The invention discloses a track control method of a dual-transformer series resonance dual-active bridge DC-DC converter topology. This method first designs the control locus of the primary and secondary side shifting the phase angle outward and the secondary side shifting the phase angle inward. The high-voltage side voltage and the low-voltage side voltage of the converter are sampled through the sampling circuit. The digital control circuit is used to calculate the external phase angle of the primary and secondary sides and the internal phase angle of the secondary side of the current control variable. According to the control track, control the original secondary side external phase angle and the secondary side internal phase angle to always move along the track, so as to ensure soft switching conditions and minimum circulation control; output the control quantity through the drive circuit, and then control the operation of the converter . In this method, the closed-loop control follows the control trajectory based on fundamental wave analysis (FCA) by adjusting the phase shift angle and high-level duty cycle, which can greatly improve control flexibility, significantly reduce circulating current, improve efficiency, and ensure All soft switching is achieved over the full load range.

The invention provides a brush direct-current motor which possesses a plurality brushes and can restrain the increase of a motor size so as to reduce ineffective circulating current for motor performance and to minimize calorific value. The brush direct-current motor possesses a first brush, a second brush homopolar with the first brush, and a choking coil in connection with the first brush and the second brush; one end of the choking coil is respectively in connection with the first brush and the second brush in a series connection mode; the choking coil is configured in such as way that the longer direction of the choking coil is in the diameter direction of the motor.

The invention discloses a single 24-pulse dry traction rectifier transformer with double-bridge windings arranged in a mirroring manner. The double-bridge winding adopts an axial double-split double-bridge four-winding structure, and each phase winding is nested on three conjugate iron cores which are sequentially arranged at intervals; the windings comprise three sets of primary side upper bridgewindings, three sets of primary side lower bridge windings, three sets of secondary side upper bridge triangular windings, three sets of secondary side lower bridge star-shaped windings, three sets of secondary side upper bridge extension windings, three sets of secondary side lower bridge extension windings, three sets of secondary side upper bridge common side windings and three sets of secondary side lower bridge common side windings. The size of the transformer is remarkably reduced, the manufacturing cost of the transformer is reduced, the transformer manufacturing process is simplified,and the electric energy quality of a rectifier system is improved. The short circuit impedance of the primary side single-phase winding to each set of secondary side single-phase winding can be completely consistent, and the short circuit impedance of the primary side three-phase winding to each set of secondary side three-phase winding can be completely consistent, so that the circulating current between the secondary side windings of the transformer is effectively reduced, and the local winding overheating phenomenon of the secondary side windings is prevented.

The present invention relates to the control field of hybrid DC transmission system, and discloses a method for suppressing multi-MMC parallel circulating current after a series converter type hybrid DC line fault, comprising: during the phase shift period after the DC line fault, the three parallel converters MMC1, MMC2, and MMC3 on the inverter side of the LCC-MMC series hybrid DC transmission system are switched from a master-slave control mode to a fixed DC current control for converter MMC1, and droop control for converter MMC2 and converter MMC3, and the DC current command values ​​of converter MMC2 and converter MMC3 are set to half of the DC current command value in steady state; after the fault is repaired, the converters MMC1, MMC2, and MMC3 are switched back to the master-slave control mode after a fixed deionization time t. The present invention can well control the DC current of each MMC during the recovery process to ensure the rapid and stable recovery of the system.

The permanent magnet synchronous motor (50) is provided with a stator (8), a plurality of teeth (2T) arranged on the stator (8) at equal intervals in angle, and coils (1) wound on the plurality of teeth (2T) in a concentrated winding manner. The coils (1) form a three-phase delta connection. In a magnetic closed circuit, a magnetic flux generated from a coil (1) wound around one of two adjacent teeth included in a plurality of teeth (2T) passes through the tip portions of the two teeth, passes through a coil (1) wound around the other of the two teeth, and returns to the coil (1) wound around the one of the two teeth through the core seat portions of the two teeth. The magnetic resistance of the magnetic closed circuit when the coils (1) wound around the two teeth are in the same phase is smaller than the magnetic resistance of the magnetic closed circuit when the coils (1) wound around the two teeth are out of phase.

The embodiment of the invention discloses an intelligent load regulation circuit and control system, and is used for solving the technical problems in the prior art that when a balance between supply and demand is realized through electric power energy storage, electric power energy storage scale development is limited by economic cost and function bottlenecks, many higher harmonics are generated when a reactive compensator is adopted, the device size is relatively large and the cost is relatively high. The intelligent load regulation control system provided by the invention includes an intelligent load regulation circuit, three-phase non-key loads, three-phase key loads, a voltage controller, a central processing unit and a phase locked loop; the intelligent load regulation circuit is in series connection with the three-phase non-key loads to form an intelligent load, and the intelligent load is in parallel connection with the three-phase key loads; the input end of the phase locked loop is connected with a power distribution network A phase, and the output end of the phase locked loop is connected with the central processing unit; the input end of the voltage controller is connected with three phases of the power distribution network, and the output end of the voltage controller is connected with the central processing unit; and the output end of the central processing unit is connected with the intelligent load regulation circuit.

The invention discloses a non-master / slave self-current-sharing grid-connected parallel uninterrupted power supply system and a power supply method thereof, and belongs to the technical field of power electronics. The system mainly comprises two or more parallel same uninterrupted power supply system units, wherein each uninterrupted power supply system unit comprises four single-phase full-bridge converters (H1-H4), three industrial frequency inductors (LS, L1, L2), a high frequency inductor (L), a direct current filter capacitor (C1), an alternating current filter capacitor (C2), an isolation transformer (T), two bidirectional thyristors (K1 and K2), an air switch (B) and a storage battery (VB); the input side of each uninterrupted power supply system unit is connected with the power grid through the air switch (B); and various uninterrupted power supply system units pass through the second and third industrial frequency inductors (L1 and L2) and the alternating current filter capacitor (C2), are connected in parallel and are connected with the power grid through the two bidirectional thyristors (K1 and K2). The bidirectional energy flow between the uninterrupted power supply and the power grid can be achieved, the power supply system is a green load relative to the power grid, and the efficiency and dynamic response speed of a parallel system are improved.