Application method of three-phase PFC integrated magnetic technology

Abstract

This invention relates to the field of integrated design of power electronic converters and magnetic components, and discloses an application method of three-phase PFC integrated magnetic technology, including: configuring excitation windings in the independent magnetic circuit branches of the magnetic core so that the excitation currents of each phase differ by a phase angle of 120° on the time axis; establishing a magnetic flux balance path in the common area inside the magnetic core, and forming a virtual magnetic neutral point with equal magnetic potential by utilizing the spatial vector synthesis and instantaneous polarity cancellation of the fundamental magnetic flux; setting a non-uniform magnetoresistive layer between the side column and the middle column to establish a gradient magnetoresistive distribution field, guiding the high-frequency ripple magnetic flux to be constrained within a specific leakage magnetic path, and orthogonally distributed with the main energy conversion path in electromagnetic space. This invention achieves electromagnetic decoupling of the inductance parameters of each phase of the integrated magnetic component by constructing a virtual magnetopotential zero point and orthogonal magnetic circuits, maintaining the independence of dynamic response, eliminating cross-phase parameter disturbances, and reducing the overall volume of the magnetic component.

Description

Technical Field

[0001] This invention relates to an application method of three-phase PFC integrated magnetic technology, belonging to the field of power electronic converter and magnetic component integrated design. Background Technology

[0002] Current charging power supplies pursue high power density, and apply integrated magnetic technology to integrate three-phase power inductors into a unified magnetic core to reduce component size and manufacturing costs. Under high-frequency and high-power conditions, the high integration of magnetic components induces deep overlap of magnetic circuit paths, forming cross-phase dynamic coupling. Due to the saturation characteristics of magnetic materials and the distribution law of magnetic flux, there is a conflict between the independence of electromagnetic parameters and the degree of integration. The three-phase magnetic flux is forced to converge on the common path of the magnetic core, causing the single-phase parameters to be pulled by the load fluctuations of the other two phases, inducing nonlinear frequency shift and current distortion. The system usually uses back-end control algorithm compensation, which increases the processor's computing load, and the magnetic circuit saturation hysteresis increases the risk of system parameter jitter.

[0003] Besides the limitations of physical hardware form, the lack of logic matching at the control level also restricts performance improvement. For example, Chinese invention patent CN111462981B discloses an integrated magnetic component that uses differential-mode and common-mode magnetic cores spaced apart to guide magnetic flux through the surface of the cores. This mode relies on static physical gap isolation and does not consider the phase relationship of the magnetomotive force and dynamic energy distribution of the three-phase system under frequency conversion control. Under transient step changes or unbalanced conditions, the static isolation mode cannot actively suppress cross-phase electromagnetic interference, and the equivalent resonant inductance value drifts with load fluctuations, increasing the complexity of back-end calculations. The calculation burden is too heavy, making it difficult to maintain the consistency of the gain curve across the entire load range; specifically, the following shortcomings exist: the magnetic flux paths of each phase within the integrated magnetic circuit lack isolation, cross-phase interference induces inductance drift, and disrupts the symmetry of the three-phase parameters; the common magnetic circuit forms local magnetic saturation under high current density, triggering a sudden change in permeability, resulting in uneven distribution of heat loss within the magnetic core; the high-frequency leakage magnetic field generated during energy storage lacks closed-loop constraint, and the spread of stray magnetic flux into space increases the difficulty of electromagnetic interference protection; increasing the cross-sectional area of ​​the magnetic core or setting a physical air gap to try to reduce coupling leads to an increase in the volume of magnetic components or a decrease in leakage inductance control accuracy.

[0004] Therefore, the technical problem to be solved by this invention is how to utilize the magnetic potential distribution law inside the magnetic circuit to construct a logically independent energy conversion path, achieve physical-level decoupling of cross-phase parameters while maintaining high integration, and solve the problem of mutual interference of magnetic circuits under frequency conversion control. Summary of the Invention

[0005] To address the problems mentioned in the background art, the technical solution of the present invention is as follows: A method for applying three-phase PFC integrated magnetic technology, comprising the following steps: Step S1: Excitation windings are set in the three independent magnetic circuit branches of the magnetic core, so that the power conversion excitation currents corresponding to each phase excitation winding are 120° phase angle apart within the power frequency cycle. Step S2: Establish a magnetic flux balance path in the common magnetic flux convergence region inside the magnetic core. By controlling the fundamental magnetic flux of each phase to perform magnetomotive force vector synthesis in the common magnetic flux convergence region, the phase difference characteristics of the power conversion excitation current are used to induce the fundamental magnetic flux of each phase to perform instantaneous polarity cancellation in the common magnetic flux convergence region, forming a virtual magnetic neutral point with equal magnetic potential inside the magnetic core. Step S3: A non-uniform magnetoresistive layer is set between the side pillars and the middle pillar of the magnetic core to establish a magnetoresistive distribution field with a preset gradient. The magnetoresistive distribution field is used to perform directional guidance on the leakage flux generated by each phase excitation winding, and the high-frequency ripple flux is constrained within a specific leakage flux path defined by the non-uniform magnetoresistive layer. The specific leakage flux path and the main energy conversion path where the virtual magnetic neutral point is located are orthogonally distributed in the electromagnetic topology space to maintain the electromagnetic decoupling of the inductance parameters of each phase and the independence of the dynamic response in the integrated state.

[0006] Preferably, step S2 includes: adjusting the magnetic circuit cross-sectional area and effective permeability of the common magnetic flux collection region according to the total magnetomotive force conservation law of the electromagnetic conversion system where the three-phase excitation winding is located under balanced operating conditions, so that the net magnetic flux density of the common magnetic flux collection region is at zero at any time, and establishing a magnetic potential balance point inside the magnetic core that is equivalent to the connection point of discrete magnetic elements, thereby reducing the coupling of cross-phase dynamic parameters and maintaining the stability of the resonant frequency of each phase during power conversion.

[0007] Preferably, the establishment of a magnetoresistive distribution field with a preset gradient in step S3 includes: embedding a high magnetoresistive dielectric layer at the junction of the magnetic circuits of the side column and the middle column; by setting the physical thickness and permeability of the high magnetoresistive dielectric layer, making the equivalent magnetoresistive of a specific leakage magnetic path greater than the equivalent magnetoresistive of the main energy conversion path; forcing the differential mode ripple flux generated by the power switching action to the edge closed loop of the magnetic core; reducing the intensity of the high-frequency ripple flux entering the middle column; and maintaining the consistency of the gain curve across the entire load range.

[0008] Preferably, in step S3, the high-frequency ripple flux is constrained within a specific leakage flux path defined by the non-uniform magnetoresistive layer, satisfying the following relationship: ,in, This is the equivalent resonant inductance value for the corresponding phase; This refers to the number of turns of the corresponding phase excitation winding; The physical length of each discrete air gap in the non-uniform magnetoresistive layer is expressed in mm. The effective cross-sectional area of ​​each discrete air gap is expressed in mm². The vacuum permeability; The equivalent magnetic reluctance of the magnetic material portion in a specific leakage magnetic path; by adjusting the physical length or effective cross-sectional area The equivalent resonant inductance value can be set independently.

[0009] Preferably, the method further includes the following steps: Step S4, obtaining the offset of the instantaneous current of each phase excitation winding relative to the preset balance reference, adjusting the pulse width of the switching frequency of each phase according to the offset to compensate for the excitation balance error caused by the offset of the virtual magnetic neutral point, and reducing the AC loss of each phase excitation winding by adjusting the distribution ratio of magnetic field energy between a specific leakage magnetic path and the main energy conversion path.

[0010] Preferably, the non-uniform magnetoresistive layer in step S3 includes: filling the gap between the side pillars and the middle pillar with a stepped air gap structure or a material with gradually varying magnetic permeability, so that the magnetic voltage drop inside the magnetic circuit exhibits a non-linear distribution in the spatial dimension, forcing the fundamental energy flow required for power conversion to pass through the central main magnetic circuit, and restricting the resonant energy flow generated by the high-frequency pulse current to the edge air gap path.

[0011] Preferably, the method further includes the following steps: Step S5, using the closed loop formed by the magnetic cover and the side post of the magnetic core to shield the internal leakage magnetic field, confining the high-frequency stray magnetic field generated by each phase excitation winding inside the magnetic core, and limiting the diffusion of magnetic lines of force to the external space.

[0012] Preferably, in step S1, excitation windings are respectively set in the three independent magnetic circuit branches of the magnetic core. Specifically, the first phase winding, the second phase winding and the third phase winding are respectively placed in the three independent magnetic circuit branches of the magnetic core. The magnetic flux generated by each phase winding converges in the central column, and the effective cross-sectional area of ​​the central column is not less than 0.5 times the sum of the cross-sectional areas of the independent magnetic circuit branches.

[0013] Preferably, the method further includes the following steps: Step S6, setting metal heat sinks on the outside of each phase excitation winding to establish a heat conduction path shared with the magnetic core, balancing the temperature rise distribution inside the integrated magnetic component, so as to maintain the stability of the magnetoresistive parameters of the non-uniform magnetoresistive layer under different operating conditions.

[0014] Preferably, the magnetic circuit transformation process consisting of steps S1 to S3 performs power factor correction of the power converter. By coupling the inductor storage function with the magnetoelectric transformation function, the decoupled operation of each phase control loop is achieved under the condition of reduced magnetic component volume.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. In three-phase PFC integrated magnetic technology, the vector characteristics of the three-phase primary windings with a mutual difference of 120 degrees are utilized to configure the magnetic reluctance distribution of the common path of the magnetic core. This induces the three-phase fundamental magnetic flux to perform spatial vector summation in the current-collecting region, so that the instantaneous magnetic flux intensity inside the common path cancels each other out under the three-phase balanced operating condition. A virtual magnetic neutral point is constructed inside the integrated magnetic component, and the power conversion process of each phase is electromagnetically independent. This eliminates the cross-phase dynamic parameter disturbance caused by magnetic circuit overlap in the deep integration state of the three-phase system, and ensures the stability of the resonant frequency of each phase in the frequency conversion control.

[0016] 2. A sub-magnetic circuit topology is defined inside the magnetic components. By utilizing the pre-set magnetic reluctance gradient difference between the side posts and the middle post, the leakage flux of the resonant inductor is constrained to a specific path. This specific path and the main power conversion path are orthogonally distributed in spatial orientation and electromagnetic path. The resonant energy storage and release process does not enter the main magnetic circuit, achieving physical integration and electromagnetic function decoupling. This avoids the inductance drift caused by the saturation of the main magnetic circuit when the load power changes, maintains the consistency of the gain curve across the entire load range, and reduces the dependence on closed-loop control algorithm compensation. The magnetic circuit path is constructed to constrain the leakage magnetic field generated by the winding within the closed magnetic core composed of the side posts, middle post, and magnetic cover. During high-frequency switching, the magnetic flux performs self-balancing distribution within the magnetic circuit, suppressing the diffusion of magnetic lines of force to the external space, reducing common-mode radiation noise generated in the inductor winding. The shielding effect originates from the physical closed-loop structure of the magnetic circuit, improving the power conversion efficiency, ensuring the electromagnetic cleanliness of the signal acquisition link inside the high-density module, and solving the problem of uncontrolled electromagnetic interference inside the three-phase power integrated system.

[0017] 3. By reorganizing and integrating the magnetic circuit path of the magnetic components, the copper magnetic loss generated by the three-phase winding is uniformly distributed within the magnetic core volume. When the system is under unbalanced load conditions, the generated magnetomotive force bias is transiently discharged through the preset high magnetic reluctance compensation area of ​​the magnetic core, avoiding the accumulation of magnetic flux in local areas and causing excessive temperature rise. The self-balancing mechanism of thermal characteristics is used to prevent the nonlinear drastic change of magnetic permeability caused by temperature rise, ensuring that the system maintains a balanced state of thermal stress in all parts under high-temperature operating conditions, improving the thermal management reliability and long-term operational stability of the power converter. The parameter decoupling characteristics are achieved by reorganizing the magnetic circuit logic, so that the voltage transformation relationship of the three-phase circuit and the resonant energy transfer process are adjusted synchronously. The excitation magnetic flux generated by the main winding and the energy storage magnetic flux generated by the resonant inductor form a non-intrusive dynamic coupling mode inside the magnetic circuit. When the current passes through the winding, the waveform maintains a high degree of symmetry, suppressing the accumulation of DC component in the magnetic core, reducing the risk of magnetic saturation, and solving the stability problem of three-phase complex operating conditions. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the input EMI filtering and soft-start protection circuit of the three-phase PFC integrated magnetic system of the present invention; Figure 2This is a bar chart comparing the current deviation compensation effect of the present invention under different temperature conditions; Figure 3 The graph shows the response curves of the phase current ripple signal under healthy and worn conditions as a function of phase angle. Figure 4 This is a flowchart illustrating the system operation logic of the present invention, which includes a steady-state maintenance and dynamic compensation mechanism. Figure 5 This is the main circuit diagram of the three-phase PFC integrated magnetic technology application system of the present invention. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the scope of protection of the present invention.

[0020] This invention provides a three-phase The integrated magnetic technology application method integrates a multiphase power inductor unit and a resonant inductor into a single magnetic core structure. It utilizes the temporal symmetry of the three-phase currents to construct a self-balancing magnetic flux distribution field within the magnetic circuit. The physical entities involved in the application method include a magnetic core with three independent magnetic circuit branches, excitation windings set on the independent magnetic circuit branches, and a common magnetic flux collection area in the central region of the magnetic core. Addressing the volume redundancy and electromagnetic coupling interference caused by the independent magnetic circuits of discrete inductors under frequency conversion control, this invention sets excitation windings in the three independent magnetic circuit branches of the magnetic core, ensuring that the power conversion excitation currents corresponding to the first, second, and third phase excitation windings are mutually differential within the power frequency cycle. The phase angle, this phase difference configuration, causes the main magnetic flux generated by each phase to be staggered along the time axis, thus providing the physical premise for the magnetic flux vector synthesis within the magnetic circuit. In specific operating procedures, the system drives the three-phase bridge circuit according to the pulse width modulation signal, so that the current waveform flowing through each excitation winding satisfies the mutual difference. This invention addresses the timing characteristics of the magnetic core, reducing the direct impact of single-phase current peaks on the total magnetic flux intensity. To mitigate the nonlinear parameter disturbances caused by the deep overlap of magnetic flux paths between phases within the integrated magnetic components, the invention establishes a magnetic flux balance path in the common magnetic flux convergence region within the core. By controlling the fundamental magnetic flux of each phase to perform magnetomotive force vector synthesis in the common magnetic flux convergence region, and utilizing the phase difference characteristics of the power conversion excitation current, the fundamental magnetic flux of each phase is induced to perform instantaneous polarity cancellation in the common magnetic flux convergence region. This creates a virtual magnetic neutral point with equal magnetic potential within the core. Based on the law of total magnetomotive force conservation under three-phase equilibrium conditions, by adjusting the magnetic circuit cross-sectional area and effective permeability of the common magnetic flux convergence region, the net magnetic flux density of the common magnetic flux convergence region is kept at zero at any given time. This establishes a magnetic potential balance point within the core, equivalent to the connection point of discrete magnetic components, reducing cross-phase dynamic parameter coupling and maintaining the stability of the resonant frequencies of each phase during power conversion.

[0021] When determining the physical specifications of the common magnetic flux collection area, the system executes a matching procedure between magnetic flux density and magnetic potential balance, and the effective cross-sectional area of ​​the common magnetic flux collection area is determined. The cross-sectional area of ​​each independent magnetic circuit branch The following geometric constraints must be satisfied: ,in The effective cross-sectional area of ​​the common magnetic flux convergence area, in units of ; The cross-sectional area of ​​each independent magnetic circuit branch is given in units of... By setting the effective cross-sectional area of ​​the common magnetic flux convergence area to be no less than the cross-sectional area of ​​the branch circuit. To ensure that the flux density of the central path remains within the linear region of the material's magnetization curve during spatial vector synthesis of the three-phase fundamental magnetic flux, this invention avoids virtual magnetic neutral point potential drift caused by local magnetic saturation induced by narrow cross-sections. Simultaneously, the effective permeability of the material in the common flux convergence region is set lower than the initial permeability of the independent magnetic circuit branches. This permeability difference creates a high reluctance barrier at the core center, causing inter-phase interference fluxes to preferentially close within their respective independent magnetic circuit branches, maintaining the parameter independence of the magnetic components under three-phase asymmetric excitation. Furthermore, to address the risk of local core saturation caused by inconsistent instantaneous duty cycles of the three phases, this invention incorporates a non-uniform reluctance layer between the side pillars and the central pillar of the core, establishing a layer with a preset gradient. The magnetoresistive distribution field is used to directionally guide the leakage flux generated by each phase excitation winding, confining the high-frequency ripple flux within a specific leakage path defined by the non-uniform magnetoresistive layer. This ensures that the specific leakage path and the main energy conversion path where the virtual magnetic neutral point is located are orthogonally distributed in the electromagnetic topology space. Specifically, a high magnetoresistive dielectric layer is embedded at the junction of the magnetic circuits of the side column and the middle column. By setting the physical thickness and permeability of the high magnetoresistive dielectric layer, the equivalent magnetoresistive of the specific leakage path is made greater than that of the main energy conversion path. This guides the differential-mode ripple flux generated by the power switching action to the closed loop at the edge of the magnetic core, reducing the intensity of the high-frequency ripple flux entering the middle column and maintaining the consistency of the gain curve across the entire load range.

[0022] In the calibration procedure for the inductance parameters of each phase, the equivalent resonant inductance value of the corresponding phase is... The following relationship must be satisfied: ,in The equivalent resonant inductance value for the corresponding phase is given in units of 1. ; This refers to the number of turns of the corresponding phase excitation winding; The physical length of each discrete air gap in the non-uniform magnetoresistive layer, in units of ; The effective cross-sectional area of ​​each discrete air gap, in units of ; Let be the permeability of free space, and its value is . ; The equivalent magnetic reluctance of the magnetic material portion in a specific leakage magnetic path is determined by adjusting the physical length. or effective cross-sectional area Independently set the equivalent resonant inductance value To adapt the resonant frequency to the preset converter operating range; a non-uniform magnetoresistive layer is constructed between the side pillars and the middle pillar of the magnetic core, and the physical gap is filled with a composite dielectric material with different permeability distribution or processed into a stepped air gap structure with a gradient change in step height. A gaussmeter is used to detect the magnetic induction intensity of a specific leakage magnetic path under rated excitation, and the thickness is increased or decreased accordingly. The polyimide film adjusts the physical length of each discrete air gap. and effective cross-sectional area Make the equivalent resonant inductance value To meet design specifications, the magnetoresistive distribution field established by adjusting the physical thickness guides the high-frequency ripple flux to close within a specific leakage magnetic path, ensuring that the high-frequency components and the main energy conversion path are orthogonally distributed in the spatial orientation, thus guaranteeing the stability of the resonant frequencies of each phase in the integrated structure; among which... The physical length of each discrete air gap in the non-uniform magnetoresistive layer, in units of , The effective cross-sectional area of ​​each discrete air gap, in units of , The equivalent resonant inductance value for the corresponding phase is given in units of 1. .

[0023] To maintain the independence of the dynamic response of each phase in the integrated state, this invention obtains the offset of the instantaneous current of each phase excitation winding relative to a preset balance reference. Based on the offset, the pulse width of the switching frequency of each phase is adjusted to compensate for the excitation balance error caused by the virtual magnetic neutral point offset. When the system detects that the current deviation exceeds a preset threshold, the controller performs closed-loop feedback adjustment. By adjusting the distribution ratio of magnetic field energy between a specific leakage magnetic path and the main energy conversion path, the AC loss of each phase excitation winding is reduced. The magnetic circuit transformation process is used to perform power factor correction of the power converter. By coupling the inductor storage function with the magnetoelectric conversion function, decoupled operation of the control loops of each phase is achieved under the condition of reduced magnetic component size. An induction search coil is pre-embedded in the common magnetic flux collection area inside the magnetic core, and the induction search coil is monitored for the three-phase current difference. The peak value of the induced voltage under phase angle conditions calibrates the dynamic balance of the magnetomotive force of each phase. If the permeability drift caused by the rise in core temperature of the peak value of the induced voltage exceeds [a certain threshold], [further action is required]. The controller calculates the instantaneous current of each phase excitation winding relative to the balance reference value. Current deviation Generate duty cycle correction increment Compensating for magnetomotive force deviations in each phase, fine-tuning the control signal to return the spatial position of the virtual magnetic neutral point to its physical geometric center, eliminating the risk of local magnetic saturation caused by unbalanced loads or inconsistent three-phase duty cycles, and maintaining physical-level decoupling of cross-phase parameters within a single magnetic core; among these... This is the baseline value for balance, in units of , The current deviation for the corresponding phase, in units of , For duty cycle correction increment; in the electromagnetic compatibility management regulations, the present invention uses the closed loop formed by the magnetic cover and side post of the magnetic core to shield the internal leakage magnetic field, confining the high-frequency stray magnetic field generated by each phase excitation winding inside the magnetic core, limiting the diffusion of magnetic lines of force to the external space. At the same time, metal heat sinks are set on the outside of each phase excitation winding to establish a heat conduction path shared with the magnetic core, balance the temperature rise distribution inside the integrated magnetic component, and maintain the stability of the magnetoresistive parameters of the non-uniform magnetoresistive layer under different operating conditions.

[0024] Example 1: In the power conversion environment of a high-power DC fast charging system, when the grid voltage waveform is distorted due to harmonic pollution and the load demand undergoes a transient step change, the flux linkage distribution inside the integrated magnetic components exhibits complex nonlinear overlapping characteristics. Since the first-phase excitation winding, the second-phase excitation winding, and the third-phase excitation winding are physically adjacent within a single magnetic core structure, the magnetic flux generated by each phase experiences dynamic interference along the common path, causing the equivalent resonant inductance value of the corresponding phase to... The deviation caused by the instantaneous fluctuation of the adjacent phase current causes the resonant frequency to deviate from the preset operating range, increasing the switching losses of power devices and inducing distortion of the output current of the charging module.

[0025] To resolve the conflict between deep magnetic circuit coupling and inductance stability, the system controls the power conversion excitation current flowing through each excitation winding to maintain mutual differential within the power frequency cycle. The phase relationship is utilized to induce a virtual magnetic neutral point with equal magnetic potential in the common magnetic flux convergence region inside the magnetic core by leveraging the magnetic potential vector cancellation characteristic brought about by the phase difference. This allows for spatial vector synthesis and instantaneous polarity cancellation of the fundamental magnetic flux in the common magnetic flux convergence region. Simultaneously, a non-uniform magnetoresistive layer is set between the side pillars and the middle pillar. Through the magnetoresistive distribution field, the high-frequency ripple magnetic flux generated by the switching action is guided to a specific leakage magnetic path. Since the specific leakage magnetic path and the main energy conversion path are orthogonally distributed in electromagnetic space, the power fundamental and high-frequency ripple achieve physical path separation under the guidance of the magnetoresistive gradient. This physical constraint procedure composed of timing phase balance and spatial magnetoresistive partitioning ensures that the magnetic core maintains the logical independence of the inductance parameters of each phase in the integrated structure. The system exhibits consistent impedance characteristics during the switching process across the entire load range, and the offset of the resonant points of each phase is constrained within the preset engineering tolerance range. Through the construction of the magnetopotential zero point and the orthogonal magnetic circuit design, the physical-level decoupling of the integrated magnetic component parameters is achieved, enabling the high power density power module to maintain magnetic volume reduction while improving the operational stability during dynamic adjustment.

[0026] Example 2: In the verification test of the three-phase power factor correction system of a 30kW DC charging module, when the total harmonic distortion rate of the grid voltage is 5% and the load demand fluctuates between 10% and 100% of the rated power, the stability of the virtual magnetic neutral point inside the magnetic core and the suppression efficiency of the non-uniform magnetoresistive layer on high-frequency ripple are verified. The test platform includes a three-phase half-bridge power module, a main control digital signal processor, and integrated magnetic components. The data source is a 12-bit precision oscilloscope and a 0.1-level precision power analyzer connected to key nodes of the circuit. The sampling frequency is set to 200kHz to capture transient flux characteristics during the switching cycle. The determination of the sampling frequency balances the dynamic capture accuracy and the processor's computational load, enabling the control loop to identify current increments with amplitudes greater than 10mA. Gaussian white noise with a peak power of 2W is introduced to simulate background electromagnetic interference in an industrial environment. By adjusting the geometric parameters of the non-uniform magnetoresistive layer between the side columns and the middle column, magnetic circuit response data under different configurations are obtained. Test group 1, test group 2, and test group 3 correspond to the physical length of the air gap, respectively. The preset range lower limit, median and upper limit, control group A removes the non-uniform magnetoresistance layer, control group B changes the physical length of the air gap The setting is 1.5mm, which exceeds the upper limit of the preset range.

[0027] Table 1: Comparative Test Data of Dynamic Characteristics of Application Methods of Three-Phase PFC Integrated Magnetic Technology

[0028] Analyzing the data in Table 1, when the physical length of the air gap... When the value is within the range of 0.1 mm to 1.0 mm, the magnetic neutral point potential fluctuation is suppressed to below 1.82 V, showing the polarity cancellation effect of the fundamental magnetic flux in the common magnetic flux convergence region. Experimental group 2... At a diameter of 0.5mm, it exhibits an equivalent resonant inductance of 1.12%. The offset rate ensures the consistency of the resonant frequency during load step transitions. Control group A, lacking a specific leakage flux path, experiences high-frequency ripple flux directly injected into the main magnetic circuit, leading to… The offset rate increased to 6.15%. Although control group B reduced magnetic neutral point fluctuations, it was due to... Excessive reluctance causes the equivalent magnetic reluctance of the main magnetic circuit to exceed the linear region, thus... The offset rate increased dramatically to 12.38%, proving that the air gap parameters... The setting range plays a role in maintaining the balance of the magnetic circuit; when processing the original input signal containing 20dB signal-to-noise ratio interference, the deviation between the extracted magnetic circuit feature data and the preset balance benchmark in test group 2 was always less than 2.5%. As the harmonic current intensity at the input end increased from 2% to 10%, the THD of the output current in test group 3 was always maintained below 2%, and no nonlinear sudden change caused by magnetic saturation occurred.

[0029] Example 3: This example combines Figures 1 to 4 An explanation of the application method of a three-phase PFC integrated magnetic technology, such as... Figure 1 As shown, the input terminal is connected via a terminal block. , and Connected to the mains power supply, the three-phase input lines are connected in series with a specification of fuse , and To provide overcurrent protection, the front end is configured with a varistor. to and gas discharge tube Specification This constitutes a primary surge protection circuit for lightning strikes, in conjunction with an input-side discharge resistor network. to (resistance value) ), capacitance to ( )as well as capacitance to ( This forms a primary electromagnetic interference filtering network, thereby filtering out high-frequency noise in the power frequency input and establishing a preliminary electromagnetic compatibility barrier; the power transmission path after primary filtering is cascaded with two stages of common-mode inductors. and (All models are) ), the two are respectively in , and Inductive coupling is formed between the pins to suppress common-mode noise. A varistor is configured in the interstage network between the two inductors. to The secondary overvoltage protection branch is simultaneously distributed between the phase line and ground. capacitance to ( and those bridging the phase lines capacitance to (Specification This further attenuates differential and common-mode interference signals; the subsequent filter circuit has a high-density filter capacitor array connected in parallel. to ( and output side capacitance to ( ), and in conjunction with resistors to (resistance value) The final-stage discharge balancing network, composed of [various components], ensures a smooth waveform of the excitation current input to the magnetic components and eliminates residual high-voltage charge after power failure, providing a stable voltage reference for the system; the circuit's output control stage uses relays... and and the thermistor connected in parallel with it ( Implement soft-start logic to prevent power-on surge impact, ultimately via terminals , and Power is supplied to the subsequent three-phase PFC integrated magnetic components, and the system's underlying grounding network is connected via... to Grounding pad and The marker points achieve equipotential bonding, in conjunction with transistors. ,interface The drive control circuit consisting of surrounding resistors and capacitors (including...) , (Signals), together to build a highly reliable front-end hardware platform that supports power factor correction of integrated magnetic components.

[0030] like Figure 2 As shown, the horizontal axis represents the temperature variable, and 25 is selected. 40 60 And 80 Four test points are shown, with the vertical axis representing the percentage of current deviation (%). The legend clearly distinguishes between the uncompensated mode (filled with diagonal lines) and the compensated mode (filled with horizontal lines). Data shows that in the uncompensated mode, as the temperature increases from 25... Rise to 80 The current deviation exhibits a non-linear growth trend, while in the compensated mode, the current deviation at each temperature point is effectively suppressed within a low and stable range; for example... Figure 3 As shown, the horizontal axis of the coordinate system covers the phase angle range from 0 to 100, and the vertical axis scale ranges from 0 to 9A. The solid line in the figure depicts the signal evolution trajectory under healthy conditions, showing an approximately linear and gradual upward trend. At the same time, the dashed line depicts the signal trajectory under worn conditions. This curve shows a sudden peak change at the 60% phase angle position and then rapidly decays, thus revealing the specific impact of wear conditions on the dynamic response signal of the magnetic circuit.

[0031] like Figure 4 As shown, the system enters the initialization configuration state to complete the configuration of the excitation current difference of 120° and the gradient parameters of the non-uniform magnetoresistive layer. Then, after excitation injection, it enters the core steady-state operation: the virtual neutral point maintenance stage. In this stage, the fundamental magnetic flux space vector synthesis, instantaneous polarity cancellation in the common area, and magnetic potential balance operation are performed. The system is divided into two paths according to the real-time operating conditions: one is to trigger the orthogonal magnetic circuit ripple constraint state when high-frequency ripple is generated, generate high-frequency switching action, and guide the leakage flux into a specific path to achieve orthogonal distribution with the main energy path. After energy isolation is completed, this state returns to the steady-state operation module via the solid line path or points to the system power-off end process via the dashed line path. The other is to trigger the dynamic deviation compensation state when current deviation is detected, adjust the switching frequency pulse width and correct the virtual neutral point deviation according to the current deviation relative to the reference, and finally return to the steady-state operation module through the dashed line path after the excitation balance is restored.

[0032] like Figure 5 As shown, this circuit diagram fully illustrates the power conversion path of the system, including the system input side. ,enter The filter unit uses a fuse. , , and The module provides protection and utilizes capacitors. to With common mode inductor Perform the filtering task, then connect A soft-start unit, which uses three sets of parallel thermistors. to and the corresponding relays , , To achieve smooth control of the power-on process, the core component of the system is... A three-phase integrated magnetic component (core), which includes excitation windings corresponding to the three phases. , , It also includes a pre-defined magnetic flux coupling path, and integrates a virtual neutral point and a non-uniform magnetoresistive layer to achieve parameter decoupling, ultimately delivering electrical energy to... A three-phase half-bridge power module, which consists of power transistors. to High-density capacitor array to (including subarrays) It is composed of DC terminals DC+ and DC-, and finally achieves power output through DC terminals DC+ and DC-.

[0033] Example 4: Three-phase energy storage deployed in an industrial-grade energy storage station In converter operation scenarios, when a large inductive load on the grid side causes a continuous phase voltage imbalance, the virtual magnetic neutral point inside the integrated magnetic components experiences a spatial potential shift because the sum of the three-phase magnetomotive force vectors is no longer zero. This shift induces asymmetrical DC components in the magnetizing currents of the first, second, and third phase excitation windings. If the system maintains a fixed pulse width output, the common magnetic flux convergence area of ​​the magnetic core will enter a local nonlinear saturation region, increasing magnetic losses and causing the charging module to shut down due to overcurrent protection. The system then initiates a dynamic saturation point smoothing procedure to reflect the balance reference value of the real-time magnetic balance state. The controller obtains the instantaneous current of each phase excitation winding during the previous power frequency cycle by collecting the instantaneous current and performing time averaging calculations. The interrupt frequency reads the digital values ​​from the three sampling channels, and each power frequency cycle... within The values ​​of each sampling point are accumulated and divided by the number of sampling points to obtain the balance reference value under the current operating condition. The system calculates the instantaneous current of each phase excitation winding relative to the equilibrium reference value. Current deviation When the deviation of the first phase current is detected Exceeding the balance benchmark value of When the threshold is reached, a duty cycle correction instruction is triggered.

[0034] The controller is based on the current deviation. Calculate the pulse width adjustment amount for the switching frequency of each phase. Pulse width adjustment amount Deviation from current The following linear compensation relationship is satisfied: ,in, This is the adjustment increment for the duty cycle; This is the proportional adjustment coefficient, which is determined by the linearity of the magnetization curve of the core material. In this application example, it is set to a value of [value missing]. ; The current deviation for the corresponding phase, in units of ; This is the baseline value for balance, in units of During execution, if detected If the value is positive, the system reduces the switching pulse width of that phase accordingly, and reduces the magnetomotive force input of the corresponding magnetic circuit by changing the conduction time of the excitation winding, so that the virtual magnetic neutral point returns to the geometric center.

[0035] Example 5: In situations where the permeability of the core material fluctuates, the initial state calibration procedure for integrated magnetic components performs length compensation for the physical thickness of the non-uniform magnetoresistive layer. This procedure is performed on a single core without assembled windings. By injecting a test flux of a preset frequency into the energy conversion main path, a magnetic field distribution is established between the side pillars and the middle pillar of the core, utilizing the physical thickness of the high magnetoresistive dielectric layer. Adjusting the equivalent magnetic reluctance of a specific leakage magnetic path to make the equivalent magnetic reluctance of the specific leakage magnetic path... The following constraints must be satisfied: ,in, The equivalent magnetic reluctance for a specific leakage magnetic path, in units of ; The physical thickness of the high magnetoresistive dielectric layer, in units of ; Let be the permeability of free space, and its value is . ; The relative permeability of high magnetoresistivity materials; The effective cross-sectional area of ​​the discrete air gap is given by . Before installation, by replacing non-magnetic pads of different thicknesses and monitoring the leakage magnetic flux induction intensity, the induced electromotive force of the leakage magnetic path is within the preset deviation range when the magnetic density of the main magnetic circuit is at the midpoint of the linear region.

[0036] During the control parameter calibration process, the system adjusts the proportional gain. The offline calibration and data storage procedure utilizes a test vector with a known current deviation gradient to excite the three-phase excitation winding, while maintaining the ambient temperature at a certain level. In the shielded laboratory, the instantaneous current deviation of the excitation winding was collected. By constructing a mapping relationship table between the current deviation and the displacement amplitude of the magnetic neutral point, and maintaining the input balance reference value, the potential shift of the virtual magnetic neutral point is considered. Under constant conditions, the magnetic balance recovery time was measured point by point under different duty cycle compensation values. The value that minimizes the recovery time without overshoot was selected as the proportional adjustment coefficient. The calibrated values ​​are written into the controller's memory as the basis for calculating the pulse width compensation instruction, enabling the active balancing logic to maintain a preset response under the interference of the nonlinear characteristics of the magnetic components.

[0037] Example 6: In the production line consistency verification procedure for integrated magnetic components, when the system faces an imbalance of magnetic reluctance in the independent magnetic circuit branches of each phase due to magnetic core assembly tolerances, the integrated magnetic components determine the physical thickness of the high magnetic reluctance dielectric layer in the non-uniform magnetic reluctance layer by executing the static zeroing calibration procedure of the magnetic neutral point. This regulation uses the effective value as the rated current. And the phase difference A three-phase sinusoidal reference current is injected into each phase excitation winding as the excitation source. An induction search coil is set up in the common flux convergence region, and a fluxmeter is used to monitor the instantaneous flux linkage change. When the flux linkage vector in the common flux convergence region is detected... When it is not zero, the system determines the flux linkage vector and the sum of the flux linkage vectors. The modulus is used to calculate the adjustment amount of the compensated air gap, where the flux linkage vector satisfies the following physical constraint relationship: ,in, The magnitude of the synthesized magnetic flux, in units of . ; , , These represent the instantaneous magnetic flux generated by the first, second, and third phase magnetic circuits in the common magnetic flux convergence region, respectively, in units of... The calibration procedure involves replacing ceramic pads of varying thicknesses as the high magnetoresistance dielectric layer until the peak value of the induced electromotive force output by the induction search coil is lower than... This method, which aligns the spatial position of the virtual magnetic neutral point with the physical geometric center, ensures that the initial symmetry of the integrated magnetic component is unaffected by the discreteness of the manufacturing process.

[0038] When the system faces the core temperature rise caused by high-power operation, and the permeability When the operating condition deviates non-linearly with temperature, the controller executes a proportional adjustment coefficient. A dynamic temperature compensation procedure is used to maintain the suppression strength of excitation balance error. This procedure utilizes a negative temperature coefficient thermistor embedded near the end of the common flux collection region of the magnetic core to collect the core temperature. The gain parameter and proportional adjustment coefficient in the control algorithm are adjusted based on the deviation of the collected core temperature from the reference ambient temperature. With temperature The association procedure is as follows: ,in, This is the adjusted ratio after compensation; To be at the reference ambient temperature The initial proportional adjustment coefficient is set below the standard, where for ; This is the temperature compensation factor for permeability, which is preset to... ; For actual measurement of core temperature, the unit is... When the temperature rises from the rated operating temperature to At that time, the controller increases the proportional adjustment coefficient based on the calculation results. To compensate for the decrease in magnetic reluctance caused by thermal effects, the instantaneous current of each phase excitation winding is made to follow the balance reference value under thermal steady state.

[0039] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method of using a three-phase PFC integrated magnetic technology, characterized in that, Includes the following steps: Step S1: Excitation windings are set in the three independent magnetic circuit branches of the magnetic core, so that the power conversion excitation currents corresponding to each phase excitation winding are 120° phase angle apart within the power frequency cycle. Step S2: Establish a magnetic flux balance path in the common magnetic flux convergence region inside the magnetic core. By controlling the fundamental magnetic flux of each phase to perform magnetomotive force vector synthesis in the common magnetic flux convergence region, the phase difference characteristics of the power conversion excitation current are used to induce the fundamental magnetic flux of each phase to perform instantaneous polarity cancellation in the common magnetic flux convergence region, forming a virtual magnetic neutral point with equal magnetic potential inside the magnetic core. Step S3: A non-uniform magnetoresistive layer is set between the side pillars and the middle pillar of the magnetic core to establish a magnetoresistive distribution field with a preset gradient. The magnetoresistive distribution field is used to perform directional guidance on the leakage flux generated by each phase excitation winding, and the high-frequency ripple flux is constrained within a specific leakage flux path defined by the non-uniform magnetoresistive layer. The specific leakage flux path and the main energy conversion path where the virtual magnetic neutral point is located are orthogonally distributed in the electromagnetic topology space to maintain the electromagnetic decoupling of the inductance parameters of each phase and the independence of the dynamic response in the integrated state.

2. The method of claim 1, wherein the three-phase PFC integrated magnetic technology is applied to a power supply of a three-phase motor. Step S2 includes: based on the law of conservation of total magnetomotive force of the electromagnetic conversion system where the three-phase excitation winding is located under balanced conditions, adjusting the magnetic circuit cross-sectional area and effective permeability of the common magnetic flux collection area so that the net magnetic flux density of the common magnetic flux collection area is at zero at any time, establishing a magnetic potential balance point inside the magnetic core that is equivalent to the connection point of discrete magnetic elements, and reducing cross-phase dynamic parameter coupling.

3. The method of claim 1, wherein the three-phase PFC integrated magnetic technology is applied to a power supply of a three-phase motor. Step S3 establishes a magnetoresistive distribution field with a preset gradient, including: embedding a high magnetoresistive dielectric layer at the junction of the magnetic circuits of the side column and the middle column; by setting the physical thickness and permeability of the high magnetoresistive dielectric layer, making the equivalent magnetoresistive of a specific leakage magnetic path greater than the equivalent magnetoresistive of the main energy conversion path; and forcing the differential mode ripple flux generated by the power switch action to the edge closed loop of the magnetic core, thereby reducing the intensity of the high-frequency ripple flux entering the middle column.

4. The application method of three-phase PFC integrated magnetic technology according to claim 1, characterized in that, The high-frequency ripple magnetic flux is confined in the specific leakage magnetic path defined by the non-uniform magnetic reluctance layer in step S3, satisfying the following relationship: wherein, is the equivalent resonant inductance value of the corresponding phase; is the number of turns of the corresponding phase exciting winding; is the physical length of each discrete air gap in the non-uniform magnetic reluctance layer, in mm; is the effective cross-sectional area of each discrete air gap, in mm²; is the vacuum permeability; is the equivalent magnetic reluctance of the portion of the magnetic material in the specific leakage magnetic path; by adjusting the physical length or the effective cross-sectional area , the equivalent resonant inductance value is independently set.

5. The method of claim 1, wherein the three-phase PFC integrated magnetic technique is applied to a power supply. It also includes the following steps: Step S4: Obtain the offset of the instantaneous current of each phase excitation winding relative to the preset balance reference. Adjust the pulse width of the switching frequency of each phase according to the offset to compensate for the excitation balance error caused by the offset of the virtual magnetic neutral point. Reduce the AC loss of each phase excitation winding by adjusting the distribution ratio of magnetic field energy between a specific leakage magnetic path and the main energy conversion path.

6. The application method of three-phase PFC integrated magnetic technology according to claim 1, characterized in that, Step S3 involves setting a non-uniform magnetoresistive layer, including filling the gap between the side pillars and the middle pillar with a stepped air gap structure or a material with gradually varying magnetic permeability, so that the magnetic voltage drop inside the magnetic circuit exhibits a non-linear distribution in the spatial dimension, forcing the fundamental energy flow required for power conversion to pass through the central main magnetic circuit, and restricting the resonant energy flow generated by the high-frequency pulse current to the edge air gap path.

7. The application method of three-phase PFC integrated magnetic technology according to claim 1, characterized in that, It also includes the following steps: Step S5: The closed loop formed by the magnetic cover and side post of the magnetic core is used to shield the internal leakage magnetic field, and the high-frequency stray magnetic field generated by each phase excitation winding is confined inside the magnetic core, limiting the diffusion of magnetic lines of force to the external space.

8. The application method of three-phase PFC integrated magnetic technology according to claim 1, characterized in that, In step S1, excitation windings are set in the three independent magnetic circuit branches of the magnetic core respectively. Specifically, the first phase winding, the second phase winding and the third phase winding are placed in the three independent magnetic circuit branches of the magnetic core respectively. The magnetic flux generated by each phase winding converges in the middle column, and the effective cross-sectional area of ​​the middle column is not less than 0.5 times the sum of the cross-sectional areas of the independent magnetic circuit branches.

9. The application method of three-phase PFC integrated magnetic technology according to claim 1, characterized in that, It also includes the following steps: Step S6: Install metal heat sinks on the outside of each phase excitation winding to establish a heat conduction path shared with the magnetic core and balance the temperature rise distribution inside the integrated magnetic component.

10. The application method of three-phase PFC integrated magnetic technology according to claim 1, characterized in that, The magnetic circuit transformation process consisting of steps S1 to S3 performs power factor correction of the power converter. By coupling the inductor storage function with the magnetoelectric transformation function, the decoupled operation of each phase control loop is achieved under the condition of reduced magnetic component volume.

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