493 results about "Leakage inductance" patented technology

The invention provides a high-frequency circulating current calculation method for a motor simulator cascade coupling parallel structure, and the method comprises the following steps: building an equivalent decoupling circuit model of each branch in the cascade coupling parallel structure based on the voltage relation of each branch in the motor simulator cascade coupling parallel structure, wherein the equivalent decoupling circuit of each branch comprises an equivalent voltage source and an equivalent leakage inductor which are connected in series, and the equivalent leakage inductor is determined based on self-inductance and mutual inductance of a choking coil of each branch; a plurality of duty ratio intervals are divided between 0 and 1, and the number of the duty ratio intervals is equal to the number of the branches in the cascade coupling parallel structure; and using the equivalent decoupling circuit model to calculate the high-frequency circulation of each corresponding branch when the duty ratio of the modulation signal of the motor simulator is in each duty ratio interval. According to the method provided by the invention, the high-frequency circulating current of the cascade coupling parallel structure of the motor simulator can be accurately calculated, and effective support is provided for targeted design of a high-frequency circulating current suppression scheme.

The disclosure provides a method for improving the efficiency of a micro-inverter, and a dual-active-bridge-type micro-inverter. The method including: performing power modulation mode switching of a dual-active-bridge-type micro-inverter, such that the power is bi-directionally transmitted from a direct-current side to an alternating-current side and from the alternating-current side to the direct-current side, thereby reducing an effective value of a secondary side current of a transformer; and according to the modulation mode switching characteristic of the dual-active-bridge-type micro-inverter within a power frequency period, performing hybrid optimization on the turn ratio of a primary side to a secondary side and a transformer leakage inductance of a high-frequency transformer of the dual-active-bridge-type micro-inverter.

The invention discloses a magnetic integrated transformer design method and device for a CLLC converter, relates to the technical field of high-frequency transformer design, and aims at solving the technical problem that an existing magnetic integrated transformer design method for the CLLC converter is poor in design precision. The method comprises the following steps: based on a preset transformer magnetic circuit model, a preset area product method and preset constraint conditions, determining the total number of turns of primary and secondary winding coils, the number of turns of the primary and secondary winding coils distributed to left and right side columns and the length of left and right side magnetic powder core magnetic columns, further obtaining the magnetic resistance of a magnetic flux branch, and considering the magnetic flux effect of an air gap edge. The accurate air gap length is determined, the magnetic resistance at the corner of the magnetic core and the extra leakage inductance value in air near a winding coil are fully considered, the primary side leakage inductance in a target magnetic core magnetic circuit, the total amount of the target air extra primary side leakage inductance and the magnetic powder core material magnetic conductivity of the target left and right side magnetic powder core magnetic columns are determined, and then a preset coil winding mode is combined. A magnetic integrated transformer for a CLLC converter is designed.

A two-transistor flyback topology in which a portion of leakage inductance energy in the transformer is extracted and used to obtain zero voltage switching on both switching elements in any operating conditions, and in which a third low power switch eliminates parasitic oscillations and allows an operation at a determined frequency. In this topology, there are no switching losses and there are no spikes or glitches in any switching node, eliminating the need for snubbers. This topology is an “ideal two transistor flyback topology.”

The present invention relates to the technical field of transformer fault detection. Disclosed is a transformer early fault diagnosis method based on the difference between virtual and actual winding leakage magnetic field waveforms, comprising: collecting leakage magnetic field information of a non-ideal winding structure transformer by means of fiber-optic magnetic field sensors; decomposing a winding of the non-ideal winding structure transformer into a plurality of regular windings; superposing leakage magnetic fields at the ends of a plurality of regular windings to obtain a non-ideal winding end leakage magnetic field; calculating a leakage flux matrix leakage inductance parameter and a leakage magnetic field output matrix parameter on the basis of the non-ideal winding end leakage magnetic field; establishing a circuit-leakage magnetic field multi-state digital model corresponding to the transformer; and using the difference between an actual transformer leakage magnetic field waveform and a digital transformer model virtual leakage magnetic field waveform as a fault characteristic quantity, completing threshold calculation and early fault sensitivity verification, forming a waveform difference-based early fault diagnosis criterion, and determining a fault position. The present invention can achieve quick and sensitive diagnosis of early faults of transformer windings and improves device operating reliability.

The invention provides a magnetic integration optimization design method for an LLC resonant converter, and belongs to the technical field of power electronics. The integrated magnetic core structure comprises a magnetic core base with four winding magnetic columns and a top cover plate, and the magnetic integration method reduces the number and the size of magnetic elements and reduces the height of the magnetic elements. According to the magnetic core structure, the magnetic flux density is uniformly distributed, the magnetic core loss of the transformer is reduced, and the power density and efficiency of the transformer are improved. Primary side windings of the transformer are unevenly distributed on the four winding magnetic columns, secondary side windings of the transformer are evenly distributed on the winding magnetic columns, and leakage inductance is only generated on the primary side of the transformer due to the fact that the primary side windings of the transformer are unevenly distributed and the secondary side windings of the transformer are evenly distributed. Therefore, the generated leakage inductance is used as the resonant inductance of the LLC resonant converter, and integration of the transformer and the resonant inductance of the LLC resonant converter is realized. The magnetic integrated transformer with different transformation ratios and controllable leakage inductance can be realized by adjusting the number of turns of windings on the primary side and the secondary side of the transformer and air gaps of winding magnetic columns.

The active clamping circuit comprises a first energy storage element, a first branch circuit and a second branch circuit, the first branch and the second branch are connected in parallel and then connected in series with the first energy storage element; the first branch comprises a second energy storage element, and the second branch comprises an auxiliary switch tube; when the clamping circuit is in a forward charging state, the first energy storage element and the first branch are conducted to form a clamping loop; the first energy storage element and the second energy storage element absorb leakage inductance energy of the primary winding through the clamping loop; and when the clamping circuit is in a reverse excitation energy charging state for the transformer, the first energy storage element and the second branch are conducted to form a reverse excitation loop. As the voltage at the two ends is the sum of the voltage of the first energy storage element and the voltage of the second energy storage element during forward charging of the clamping circuit and is only the voltage of the first energy storage element during discharging, and the excitation voltage is smaller than the reflection voltage of the secondary winding during reverse excitation of the transformer, a secondary rectifier tube cannot be switched on, energy forward shock to the secondary side is eliminated, and the voltage of the secondary side is reduced. Therefore, the loss is reduced.

The invention discloses an efficient new energy transformer and an electric energy control system, and relates to the technical field of transformers, an input power conversion module is used for converting a direct current or alternating current variable voltage source into high-frequency alternating current for output, and a high-frequency isolation transformer module adopts a nanocrystalline-amorphous alloy mixed magnetic core. The windings are arranged in a three-layer staggered mode and provided with an oil dual-cooling system, and the output rectification inversion module is used for converting high-frequency alternating current into needed direct current or alternating current to be output and integrates the multi-phase synchronous rectification function and the active filtering function. By designing the nanocrystalline-amorphous alloy mixed magnetic core and the three-layer staggered winding, leakage inductance is reduced, the coupling coefficient is increased, the problems of leakage inductance and nonuniform magnetic flux caused by serious iron loss, large leakage inductance and unreasonable coil arrangement of a traditional single-material low-frequency iron core at medium and high frequencies are solved, hysteresis and eddy-current loss are effectively inhibited, and the service life of the low-frequency iron core is prolonged. The leakage inductance is minimized, the high-frequency transformation efficiency is improved, and the size and the weight are reduced.

The invention provides an optimal design method and device for a high-frequency transformer, and belongs to the field of high-frequency transformers. The method comprises the following steps: obtaining the value range of each design parameter of the high-frequency transformer to obtain a plurality of design schemes; under a preset constraint condition, performing multi-objective optimization on the decision variables corresponding to the plurality of design schemes to obtain optimized values of the decision variables; taking the design scheme corresponding to the optimized value of the decision variable as a target design scheme of the high-frequency transformer; wherein objective functions in the multi-objective optimization process comprise a first objective function, a second objective function and a third objective function; the first objective function is determined based on the magnetic core loss and the total loss of the litz wire winding; the second objective function is determined based on the volume of the high-frequency transformer; the third objective function is determined based on the leakage inductance value of the high-frequency transformer. According to the method, global optimization of loss, parasitic parameters, insulation design and maximum temperature rise of the high-frequency transformer can be realized.

The present application relates to the technical field of power devices, and particularly discloses a resonant leakage inductance transformer for a plate-type ozone generator, comprising: insulating bobbins, two insulating bobbins being longitudinally provided, a primary coil structure and a secondary coil structure being respectively provided on the insulating bobbins in the circumferential direction, and the two insulating bobbins being longitudinally aligned and fixed; magnetic cores, each magnetic core comprising a plurality of protruding portions, the protruding portions extending in the longitudinal direction, the plurality of protruding portions being arranged in a single transverse row, and the protruding portions located in the middle in the arrangement direction respectively longitudinally passing through the middle of the two insulating bobbins; and an insulating fixing frame, the magnetic cores being arranged in the insulating fixing frame. The primary coil structure and the secondary coil structure are each of a multi-layer wound coil structure, and ceramic tubes are inserted between adjacent layers of coils of the coil structure.

The invention provides a magnetic integrated transformer, electrical equipment and a vehicle, the magnetic integrated transformer comprises a main magnetic core, a leakage inductance magnetic core, a skeleton assembly, a primary winding and a secondary winding, the skeleton assembly comprises a main skeleton and a side skeleton, the main skeleton is provided with a central ring column and two main baffles, the leakage inductance magnetic core is arranged in the side skeleton, and the secondary winding is arranged in the central ring column. The side framework is connected with the main baffle plate at the corresponding end, the primary winding is wound on the main framework, and the secondary winding is wound on the peripheries of the leakage inductance magnetic core and the primary winding. According to the scheme, winding of the winding and assembling of the magnetic core are facilitated, the leakage inductance magnetic core is easy to assemble and accurate and stable in position, a leakage inductance magnetic field passes through the leakage inductance magnetic core with high magnetic permeability, the size occupied by the leakage inductance magnetic circuit can be greatly reduced, and therefore the overall size of the device is reduced, and by controlling the size of an air gap between the magnetic cores, the reliability of the device is improved. The magnitude of the needed leakage inductance can be accurately controlled, the leakage inductance magnetic field is mainly concentrated in one or more magnetic cores, the loss of the high-frequency effect is effectively reduced, and the efficiency of the converter is improved.

The invention relates to the technical field of inductors, in particular to a common-mode and differential-mode integrated annular inductor assembly which comprises an annular magnetic core, a first winding and a second winding, and the common-mode and differential-mode integrated annular inductor assembly is reversely wound on the annular magnetic core in a double-wire parallel winding mode to form a common-mode path. The starting end of the first winding is a first input pin, the terminating end of the first winding is a first output pin, the starting end of the second winding is a second input pin, the terminating end of the second winding is a second output pin, and the first output pin and the second output pin are connected with a load through a circuit topology and are automatically connected in series to form a differential mode path. Through magnetic core partition and annular distributed air gap design, collaborative optimization of common-mode magnetic field offset and differential-mode anti-saturation is completed, and the technical effects of high-frequency common-mode suppression and broadband differential-mode suppression are achieved; through a gradient leakage inductance winding technology, dynamic adaptation of a differential mode inductance value is completed, and the flexible filtering requirement of adapting to different noise spectrums is met.

The invention belongs to the technical field of nuclear power, and particularly relates to a ground capacitance measurement method based on series capacitance and high-frequency signal injection. In order to solve the problem that a traditional signal injection method cannot accurately calculate the ground capacitance level of a power distribution network, the invention provides a ground capacitance measurement method based on a series capacitor and high-frequency signal injection. The leakage inductance of the voltage transformer is accurately measured by injecting the high-frequency signal, so that a resonance point is convenient to find during frequency sweeping, and the resonance point measured during frequency sweeping is more accurate.

The present disclosure provides an active clamp flyback converter and a control method, and relates to the technical field of converter. The control method includes: in response to that an input voltage of the active clamp flyback converter is less than a preset voltage threshold, or the input voltage of the active clamp flyback converter is less than a product of an output voltage of the active clamp flyback converter and a turns ratio of the transformer, in a same switching cycle, controlling the clamp switch to turn on when the transformer is in a demagnetization stage; and controlling the clamp switch to turn off when a resonant current of the clamp capacitor and a leakage inductance of the transformer reaches a preset current threshold.

The application provides a high-frequency circulating current calculation method for a motor simulator cascaded coupling parallel structure, comprising the following steps: establishing an equivalent decoupling circuit model of each branch in the cascaded coupling parallel structure based on the voltage relationship of each branch in the motor simulator cascaded coupling parallel structure, wherein the equivalent decoupling circuit of each branch comprises an equivalent voltage source and an equivalent leakage inductance connected in series, and the equivalent leakage inductance is determined based on the self-inductance and mutual inductance of each branch choke; dividing a plurality of duty cycle intervals between 0 and 1, and the number of duty cycle intervals is equal to the number of branches in the cascaded coupling parallel structure; and using the equivalent decoupling circuit model to calculate the high-frequency circulating current of each branch when the duty cycle of the modulation signal of the motor simulator is in each duty cycle interval. The method provided by the application can accurately calculate the high-frequency circulating current of the motor simulator cascaded coupling parallel structure, and provides effective support for the targeted design of a high-frequency circulating current suppression scheme.

An annular-shaped spacer member is attached in a split manner in a circumferential direction of a winding shaft portion of a bobbin through which middle leg portions are inserted. The spacer member includes: a cylindrical portion on which an annular third core is placed; and flange portions provided at both ends thereof. The third core is split in the circumferential direction and mounted on the outer circumferential portion of the cylindrical portion of the spacer member in a state in which, of elements of the shape of the third core and the material characteristic of the third core, the magnitude of at least one of the elements is set so that a desired leakage inductance value is generated.

A micro inverter having a plurality of independent inputs and a photovoltaic system are provided. The micro inverter includes multiple isolated DC-DC converters and a DC-AC converter. Each isolated DC-DC converter of the isolated DC-DC converters includes an inverter H-bridge, a transformer and a voltage-multiplying rectifier. An input terminal of the inverter H-bridges is configured to connect to a direct-current power supply. A secondary winding of the transformer is connected to an input terminal of the voltage-multiplying rectifier. An output terminal of the voltage-multiplying rectifier is connected to an input terminal of the DC-AC converter. A leakage inductor or an external inductor of the transformer forms series resonance along with a capacitor in the voltage-multiplying rectifier.

The invention provides a current stress optimization method and system for an isolated bidirectional three-phase energy storage converter, and relates to the technical field of power conversion. Firstly, Fourier series analysis is carried out on primary and secondary side voltages of a high-frequency transformer, and leakage inductance current and active power are calculated accordingly; carrying out per-unit processing on the active power and the square of the primary side current, and obtaining the active power and the square of the peak current under the fundamental component based on a per-unit processing result; then, with the minimum square of the peak current as an optimization target and the transmission power under the fundamental component as a constraint, constructing and solving a current stress optimization model so as to obtain an optimal matrix converter parameter; and finally, performing current stress optimization control based on the optimal parameters to reduce the current stress. According to the method, the current stress is remarkably reduced while the set transmission power requirement is met, the direct current side dynamic response is improved, and the converter performance is improved.

The invention discloses a permanent magnet synchronous motor zero-order radial force analysis modeling method based on lumped parameters, and belongs to the technical field of motor electromagnetic vibration noise analysis. According to the method, the flux linkage is taken as a key correlation variable, and the relationship between the air gap flux density distribution and the current is revealed by reasonably selecting lumped parameters. The relationship between current and flux linkage is established by using incremental inductance, permanent magnet flux linkage and armature flux linkage are separated by using apparent inductance, and the influence of flux leakage on air gap armature flux linkage is analyzed by using stator leakage inductance. According to a winding structure, an air gap flux density distribution basic waveform is established, and the armature air gap flux density distribution characteristic is further refined by analyzing the influence of a stator structure and a magnetic bridge. In addition to traditional lumped parameters, new lumped parameters are also defined for establishing an analytical model. Compared with a finite element model in the prior art, the analytical model disclosed by the invention has higher precision, and can intuitively express the relationship among the current, the lumped parameter and the zero-order radial electromagnetic force.

The present application discloses a planar transformer, which relates to the technical field of transformers, and includes a magnetic core and a plurality of PCB boards; the magnetic core includes a base, a column and a cover; both ends of the top of the base have vertical plates, and an installation space is formed between the two vertical plates; the column is fixedly installed on the top of the base, the axis of the column is vertical, and the column is centered in the installation space; the cover is arranged on the top of the base, and the cover and the base are detachably connected; after the cover is connected to the base, the cover contacts and abuts against the top of the column; a clearance opening is opened at the center of the PCB board, and after the PCB board is installed on the magnetic core, the two ends of the PCB board extend out of the outside of the two openings of the installation space respectively. The present application has a small space occupancy rate, a low heat exchange loss and a good secondary leakage inductance, thereby making the application of planar transformers more extensive.

The invention discloses an absorption circuit for a multi-path parallel flyback switching power supply MOS (Metal Oxide Semiconductor) tube, which is used for controlling voltage between a drain electrode and a source electrode of the MOS tube and comprises a first flyback circuit, a second flyback circuit and an absorption circuit, and the first flyback circuit and the second flyback circuit are connected in parallel and are connected to an output end of the absorption circuit; and the high-frequency capacitors C101 and C103 respectively form a loop with the primary side leakage inductance Lm of the transformer in the first flyback circuit and the second flyback circuit, so that the voltage amplitude generated by resonance of the leakage inductance Lm and the parasitic capacitance Coss of the MOS tube is reduced. Meanwhile, fast recovery diodes D102 and D104 are conducted, so that a high-frequency capacitor C102 absorbs voltage energy, a transient voltage suppression diode D101 performs voltage clamping, and terminal voltage of an MOS tube in the flyback circuit is controlled. The circuit is verified by an actual multi-path parallel flyback switching power supply, the work is stable and reliable, the stress control effect of the MOS tube is good, and the cost is relatively low.

A method for operating a switching power converter to reduce ripple current magnitude includes (a) controlling duty cycle of a plurality power stages of the switching power converter to regulate at least one parameter of the switching power converter, each power stage including a respective power transformer, and (b) controlling an injection stage of the switching power converter to reduce voltage across leakage inductance of each power transformer, the injection stage including an injection transformer that is electrically coupled to a respective secondary winding of each power transformer.

An integrated transformer with a bypass magnetic core and a three-port on-board charger. The integrated transformer comprises a base (10), and a first C-shaped magnetic core (5) and a second C-shaped magnetic core (6) which are mounted on the base (10). Two ends of the first C-shaped magnetic core (5) and two ends of the second C-shaped magnetic core (6) are butt-jointed in pairs to form a closed magnetic ring. A first winding (W1), a third winding (W3) and a fourth winding (W4) are wound on the first C-shaped magnetic core (5), and a second winding (W2) is wound on the second C-shaped magnetic core (6). The integrated transformer further comprises a bypass magnetic core (3) which is arranged in the middle of the magnetic ring to divide the magnetic ring into a first chamber (4) and a second chamber (5). The integrated transformer reuses a bypass magnetic core and controls the coupling between transformer windings to obtain leakage inductance as resonance inductance, and by integrating four power magnetic elements in the prior art into one transformer for application in an on-board charger, the number of magnetic devices of the converter can be reduced, so that the power density of the converter can be greatly improved, the overall loss of the converter is reduced, the efficiency is improved, and the cost of the magnetic devices of the converter is lowered.

The invention belongs to the technical field of fault-tolerant motors, and particularly discloses a permanent magnet fault-tolerant motor which comprises a stator, a rotor and a choke ring, the stator comprises a plurality of stator teeth and stator windings which are evenly distributed in the circumferential direction, the stator teeth are of a discrete structure, the included angle between every two adjacent stator teeth is 360 degrees / X, X is the number of single-phase stator teeth, and X is the number of single-phase stator teeth. The stator windings are embedded into grooves of the stator teeth in an axial distribution mode; the rotor is located on the inner side of the stator and comprises a rotor iron core and magnetic steel, the magnetic steel is a surface-mounted permanent magnet, the two magnetic steel with opposite polarities form a pair of magnetic poles, and the two magnetic steel in each pair of magnetic poles are arranged in the axial direction and are aligned with stator teeth; the choke rings are axially distributed between adjacent stator teeth, each choke ring is of a rectangular ring structure, and a single choke ring forms a fault-tolerant unit. When the permanent magnet fault-tolerant motor is in turn-to-turn or single-phase short circuit, the current suppression ring generates high-impedance leakage inductance without time delay, the short-circuit current is suppressed, the fault tolerance of the motor is improved, fault detection is not needed, and the reliability is high.

The invention discloses a small-size high-power power supply design method and application based on a planar transformer, and the method comprises the following steps: S1, employing a planar transformer structure comprising at least two layers of PCB windings and a low-loss ferrite magnetic core, enabling the windings to be formed through the etching of PCB copper foils, and enabling the leakage inductance of the adjacent winding layers to be reduced in a staggered stacking manner; s2, the planar transformer is integrated into an LLC resonant half-bridge topology circuit, and soft switching operation of a power supply system under high frequency is achieved by adjusting the primary and secondary turn ratio and resonance parameters of the planar transformer. PCB copper foil etching windings and low-loss ferrite magnetic cores are adopted, leakage inductance is reduced by stacking winding layers in a staggered mode, and the reliability of the power supply system is improved; the planar transformer is combined with laser cutting to precisely control an air gap, so that primary and secondary coupling coefficients are improved to a high coupling state, energy loss is reduced, the size of the transformer is effectively reduced, the planar transformer can be popularized to the fields of industrial power supplies, energy storage systems and the like, and balance of small size and high power is achieved through collaborative optimization of the planar transformer and a topological structure.

Disclosed in the present invention are an integrated transformer capable of utilizing leakage inductance, and a three-port on-board charger. The integrated transformer comprises a first C-shaped magnetic core and a second C-shaped magnetic core, wherein two ends of the first C-shaped magnetic core are respectively butt-jointed to two ends of the second C-shaped magnetic core to form a closed magnetic ring, a first winding and a third winding are wound round the first C-shaped magnetic core, and a second winding is wound round the second C-shaped magnetic core. The integrated transformer further comprises a bypass magnetic core, wherein the bypass magnetic core is arranged in the middle of the magnetic ring, and divides the interior of the magnetic ring into a first cavity and a second cavity. The present invention reuses a bypass magnetic core, and controls the coupling between transformer windings to obtain leakage inductance as resonant inductance; and four power magnetic elements in the prior art are integrated into a transformer, and the transformer is then applied to an on-board charger. Thus, the number of magnetic devices of a converter is reduced, and thus the costs are reduced; the power density of the converter is significantly improved; the overall loss of the converter is reduced, and the efficiency is improved; and the costs of the magnetic devices of the converter are reduced.

The invention discloses a vernier permanent magnet fault-tolerant motor with asymmetric stator teeth, which belongs to the field of fault-tolerant motors and is characterized in that stator slots of the vernier permanent magnet fault-tolerant motor comprise open slots and closed slots; the open slots and the closed slots are equal in number and are arranged in a staggered manner; the tooth widths of the two stator teeth adjacent to the same closed slot are unequal, and the difference between the magnetic conductance amplitudes corresponding to the two stator teeth adjacent to the same closed slot is increased under the working condition of a short-circuit fault, so that the magnetic line of force which originally passes through a long magnetic circuit to be closed but must flow through the narrow teeth is changed to pass through the wide teeth due to the increase of the magnetic resistance; the capability of guiding magnetic lines to form a ring tooth magnetic circuit by the closed slot is enhanced, so that the leakage inductance of the ring tooth magnetic circuit slot under a short-circuit fault is increased, and the short-circuit resistance of the motor is enhanced; meanwhile, the span of the coil winding is closer to one polar distance, the utilization rate of the winding to a rotor excitation magnetic field and the groove area are improved, and then high torque output of the motor under the normal working condition can be guaranteed by increasing the current flowing through the grooves.

The application discloses a bidirectional DCDC circuit and a photovoltaic energy storage inverter. The photovoltaic energy storage inverter is used for connecting a photovoltaic module, a battery and an alternating current end. The bidirectional DCDC circuit comprises a first direct current end, a second direct current end, a transformer, a first full-bridge circuit connected between the first direct current end and a primary side of the transformer, a second full-bridge circuit connected between a secondary side of the transformer and the second direct current end and a first capacitor. The first full-bridge circuit is directly connected with the primary side of the transformer and / or the second full-bridge circuit is directly connected with the secondary side of the transformer. The first capacitor is located between the second full-bridge circuit and the second direct current end and is connected with positive and negative poles of the second direct current end. The bidirectional DCDC circuit provided in the application uses leakage inductance of the primary side of the transformer and the first capacitor to form an LC resonant circuit instead of an LC resonant circuit arranged at two ends of the transformer, so that the function of the resonant circuit is realized while the number and volume of electrical elements of a topological structure are reduced, thereby reducing the cost.

The application relates to the technical field of switching power supply, and discloses a bridge type low-stress passive soft switching boost power factor correction circuit, which comprises a direct current input power supply, a main power switching tube, an output filter capacitor and a coupling inductor comprising a primary side and a secondary side; a passive soft switching buffer network is connected to a main circuit of the circuit, the network comprises a diode full-bridge structure and a buffer capacitor, and the leakage inductance of the secondary side of the coupling inductor is connected between the midpoints of two bridge arms of the full-bridge structure; the application utilizes the ratio difference of the coupling inductor to generate a forward potential difference, drives the buffer capacitor to reversely charge to establish a negative voltage, and further provides a discharge circuit for the parasitic junction capacitance of the main power switching tube, so that zero voltage turn-on is realized, and high-frequency switching loss is reduced; meanwhile, the highest voltage stress of the semiconductor device is clamped in the range of the direct current output voltage through the potential restriction of the full-bridge network. The application does not need auxiliary active devices, and improves conversion efficiency and reliability while simplifying the system structure.

The invention relates to a transformer leakage inductance calculation method and device and computer equipment. The method comprises the following steps: acquiring magnetic induction intensity and vector magnetic potential of any point in an iron core window; obtaining magnetic field energy in an iron core window area based on the magnetic induction intensity and geometric parameters of the iron core window; based on the vector magnetic potential and the cross section size of the winding area, obtaining interaction energy of the current and the vector magnetic potential in the winding area; on the basis of the interaction energy and the magnetic field energy, magnetic leakage energy stored by a unit length winding is obtained; the leakage inductance of the transformer is obtained based on the total leakage flux energy of the winding and the winding current of the low-frequency equivalent circuit, and the total leakage flux energy is obtained through calculation based on the leakage flux energy stored by the winding per unit length and the winding length.