149results about How to "Reduce harmonic content" patented technology

The invention provides a PWI modulation method for an inverter. Belongs to the technical field of power electronics, and comprises the following steps: setting basic working parameters of an inverter, initializing an initial value and a change range of a phase weighting factor, and presetting a PWF regulation strategy according to load characteristics and waveform quality requirements; loading and initializing a control algorithm of the inverter, and generating a standard sine wave as a reference wave according to a preset output voltage and frequency; calculating a PWF value of each phase point according to the current load state and a preset PWF adjustment strategy, and multiplying the PWF value by a standard sine wave to generate a target modulation waveform; and selecting a carrier signal, comparing the target modulation waveform with the carrier signal, and generating a PWM signal according to a comparison result. By presetting the PWF adjusting strategy and dynamically adjusting the PWF value, the waveform quality of the output voltage of the inverter can be effectively improved, and different load characteristics and waveform quality requirements are met.

The invention discloses a multi-phase-multi-phase direct-type AC-AC converter based on an MMC and a control method of the multi-phase-multi-phase direct-type AC-AC converter. The AC-AC converter provided by the invention comprises a modular multi-level converter and N single-phase three-winding transformers, the modularized multi-level converter comprises X phase units, the input side is provided with m ports and connected with a first alternating current system, and the output side is provided with N ports and connected with a second alternating current system. Each single-phase three-winding transformer comprises a first winding, a second winding and a third winding, the first windings of the N single-phase three-winding transformers are respectively connected with N phases of a second alternating current system, and the second windings are connected with N output side ports of an upper bridge arm of the modular multilevel converter; and the third winding is connected with N output side ports of the lower bridge arm of the modular multilevel converter. The AC-AC converter is based on the principle of synthesis of differential-mode and common-mode voltage components of MMC bridge arms, and is combined with a three-winding transformer with an anti-dotted terminal, so that the number of sub-modules of the M3C topology can be further reduced, and the AC-AC converter has good expansibility and is suitable for application scenes with various special requirements.

The invention relates to a hybrid supercapacitor energy storage type converter based on an H bridge and an operation method thereof, and the energy storage type converter comprises an upper bridge arm part and a lower bridge arm part. Each of the upper bridge arm part and the lower bridge arm part comprises three bridge arms, and each bridge arm is formed by connecting n H-bridge sub-modules and a bridge arm inductor in series; the upper bridge arm part is connected with a direct current bus, and the lower bridge arm part is connected with a grounding wire; the H-bridge sub-module comprises four switch elements and an energy storage unit, the energy storage unit is a hybrid super capacitor, the four switch elements form an H-bridge structure, and the hybrid super capacitor is connected to the two ends of the H-bridge structure in parallel. According to the invention, the dual functions of energy storage and current conversion in the AC-DC interconnected power grid can be realized under the cooperation of the control strategy, and various operation requirements in different scenes can be met.

The embodiment of the invention relates to the technical field of electric power, in particular to a converter control circuit, a converter and a charging pile. The converter control circuit and the converter comprise the coupling unit, the power conversion unit, the bus unit and the control unit, one path of input of alternating current is converted into two paths or multiple paths of output by additionally arranging the coupling unit, in the multiple paths of output, current is isolated and equally divided, and the output current of the power conversion unit is improved. Meanwhile, the internal structure of the coupling unit suppresses the circulating current in the converter, and the circulating current loss in the power conversion unit is reduced. Furthermore, the power conversion unit is provided with a plurality of T-shaped three-level inversion units, so that a multi-level technology is realized, multi-voltage level is provided, and multi-level output can remarkably reduce harmonic content of output voltage and current, reduce current ripples and improve electric energy quality.

The invention discloses a current zero-crossing distortion control system and method based on a totem-pole topological converter, and relates to the technical field of power electronics. The system comprises: a control module comprising a voltage outer loop control unit and a current inner loop control unit; the voltage outer loop control unit is used for acquiring the actual output voltage and the rated bus voltage of the totem-pole topological converter, generating an input current reference value based on the actual output voltage and the rated bus voltage, and transmitting the input current reference value to the current inner loop control unit; the current inner loop control unit is used for acquiring an input current sampling value of the totem-pole topological converter and generating a modulation wave signal based on an input current reference value and the input current sampling value; and the driving module is used for receiving the modulation wave signal transmitted by the current inner loop control unit and generating a high-frequency driving signal of the high-frequency bridge arm switch tube and a power-frequency driving signal of the power-frequency bridge arm switch tube based on the modulation wave signal. According to the embodiment of the invention, the current zero-crossing distortion phenomenon can be effectively suppressed.

The invention discloses a flat wire motor winding which comprises a stator assembly, the number of pole pairs of the stator assembly is 8, the number of phases of the stator assembly is three, the stator assembly further comprises a stator iron core, 48 grooves are formed in the stator iron core and are sequentially named as 1-48 point positions according to the anticlockwise direction, the number of the grooves in each pole and each phase is 2, and the number of the grooves in each phase is 2. A plurality of flat wire winding copper wires with insulating layers are arranged on the stator core, the number of flat wire layers of the flat wire winding copper wires on the stator core is six, the number of flat wire layers is marked as 1-6 from the inner ring to the outer ring of the stator core in sequence, the plurality of flat wire winding copper wires are connected with one another through bridging lines, and the insulating layers are arranged on the insulating layers. And the plurality of flat wire winding copper wires are mutually connected to form a winding structure. Through the mode, the flat wire winding copper wires can be reversely twisted, so that the same-phase flat wire winding copper wires needing to be connected are close to each other and are intensively welded, thereby reducing bridging lines, and reducing the weight and cost of the motor.

The invention discloses a concentric unequal-turn full-slot low-harmonic winding stator, which comprises a stator core and a winding, and is characterized in that the stator core comprises a plurality of phase belts, and each phase belt comprises three stator slots; the windings wound in the three stator slots in one phase belt are wound in a single-double-layer unequal-turn manner, and are periodically distributed on the whole stator core in a surrounding manner by taking one phase belt as a period; the three stator slots in one phase belt comprise two first slot bodies and a second slot body, the second slot body is located between the two first slot bodies, and the slot sizes of the first slot bodies and the second slot body are matched with the single-layer and double-layer unequal-turn winding windings to form a matching structure with high full slot rate. The concentric single-layer and double-layer unequal-turn windings and the stator slots matched with the windings are adopted, so that the magnetic circuit distribution is more uniform while the harmonic amplitude is reduced, the static flux density distribution of the stator is greatly improved, and the motor performance is further improved.

The invention provides a medium-voltage alternating-current bidirectional flexible interconnection device, which belongs to the technical field of power distribution and comprises a first phase-shifting transformer, a second phase-shifting transformer and a three-phase current source type flexible power transmission unit, the three-phase current source type flexible power transmission unit is located between the first phase-shifting transformer and the second phase-shifting transformer, and the first medium-voltage bus and the second medium-voltage bus are located at the lower end of the total drop of any two active high voltages; and the three-phase current source type flexible power transmission unit is used for performing bidirectional scheduling on the alternating current electric energy between the first medium-voltage bus and the second medium-voltage bus under the control instruction. When temporary uneven energy distribution occurs between transformers in a power distribution network of two power distribution transformers, energy redistribution can be realized, and energy balance can be realized to the greatest extent.

The utility model belongs to the technical field of rotors, and particularly relates to a rotor punching sheet, a rotor, a motor, a power assembly and a vehicle. The rotor punching sheet comprises a plurality of magnetic poles arranged along the circumferential direction of the rotor punching sheet, each magnetic pole is provided with a magnetic steel groove group, a first groove and a slotted hole, each magnetic pole is provided with a d axis and a q axis, the magnetic poles are symmetrical about the d axis, and the adjacent magnetic poles are symmetrical about the q axis; the first groove is arranged at the intersection of the outer edge of the magnetic pole and the d shaft, the first groove is arranged at the outer side of the magnetic steel groove group in the radial direction of the rotor punching sheet, and the q shaft passes through the groove hole. According to the utility model, through the combination of the first grooves on the d-axis and the slotted holes on the q-axis, magnetic field forces in the tangential direction and the radial direction brought by a harmonic magnetic field can be reduced, lower air gap flux density and harmonic content are obtained, the torque pulsation and the radial force of the rotor punching sheet are reduced, and the purpose of reducing motor noise is achieved.

The present application provides a rotor assembly and an alternating pole motor. The rotor assembly includes a rotor core, the rotor core includes permanent magnetic poles and alternating poles arranged alternately along the circumferential direction, the permanent magnetic poles include mounting slots, permanent magnets are mounted in the mounting slots, the polarity of the permanent magnets facing the outer periphery of the rotor core is the same polarity, a first air slot and at least two second air slots are arranged on the rotor core radially outside the mounting slot, the first air slot is located on the center line of the magnetic pole, at least two second air slots are arranged at intervals along the circumferential direction and are located on both sides of the center line of the magnetic pole, along the radial direction away from the center of the rotor core, the spacing between the side walls of the at least two second air slots close to the center line of the magnetic pole gradually increases, and the first air slot is located in the expansion area of ​​the at least two second air slots. According to the rotor assembly of the present application, the problem of increased torque pulsation caused by the rich back-electromotive force harmonic content of the alternating pole motor can be effectively improved, the back-electromotive force harmonic content can be significantly reduced, and the motor performance can be improved.

The invention discloses a rail holding type suspension driving maglev train system, and relates to the technical field of maglev train systems. Decoupling of suspension, guiding and driving functions of the maglev train is achieved, the control complexity of the maglev train is reduced, and safe operation of the maglev train is guaranteed. The system comprises a vehicle body structure, an I-shaped supporting beam, a suspension system, a driving system and a safety limiting and braking system. The train body structure comprises a train and a suspension frame arranged at the bottom of the train. The two ends of the suspension frame extend downwards and then extend inwards to form a cavity, and the upper flange of the I-shaped supporting beam extends into the cavity of the suspension frame. The suspension system is arranged between the top wall surface of the cavity of the suspension frame and the upper surface of the upper flange; the driving system is arranged between the lower surface of the upper flange and the bottom wall surface of the cavity of the suspension frame; the safety limiting and braking system is arranged between the side face of the upper flange and the side wall face of the cavity of the suspension frame. The performance of the suspension driving system is improved.

The invention discloses a compound control method for improving the current control performance of a three-phase LCL type grid-connected inverter. The method comprises the following steps: establishing a system loop gain based on digital control delay; composite control is realized by adopting a mode of combining a capacitance current sampling modification mode and a delay compensation link, and the capacitance current sampling modification mode is used for shortening capacitance current sampling delay and comprises the steps of sampling grid-connected current at a wave trough of a triangular carrier wave, sampling capacitance current at a wave crest of the triangular carrier wave, and carrying out delay compensation on the grid-connected current. A modulation signal is loaded at the next grid-connected current sampling moment, and capacitance current sampling delay is shortened by half beat; the delay compensation link is used for compensating the influence of digital control delay, the influence of digital control delay is reduced by embedding a lead phase compensator in a capacitive current feedback loop, and the stability of the system and the quality of grid-connected current are improved. According to the invention, composite control is realized by adopting a mode of combining a capacitor current sampling modification mode and a delay compensation link addition mode.

The invention discloses a multi-standard power supply system and method for a locomotive test, and relates to the technical field of test power supplies, and the structural design of the system is as follows: an input power supply is a three-phase alternating current 10kV power supply; the high-voltage switch K realizes access control and isolation of the system and a public power grid, the connection reactor L realizes energy buffering and inhibits switch ripples in output current, and the soft charging circuit pre-charges the three-stage converter. The three-level converter converts three-phase alternating current 10kV into DC1500 / 750V and outputs the DC1500 / 750V to the direct-current bus, one path of the direct-current bus supplies power to a subway vehicle test line, and the other path of the direct-current bus is inverted into single-phase alternating current 25kV through the output inverter and supplies power to a railway locomotive test line. According to the invention, alternating current test conditions of railway electric traction locomotive vehicles and direct current test conditions of subway vehicles can be satisfied, reliability and quality of power supply are ensured, repeated construction is reduced, and resource waste is avoided.

The present invention discloses a boost type three-port energy storage inverter and a control method thereof. The boost type three-port energy storage inverter includes a DC power supply, a battery, a bidirectional DC-DC converter, a boost inverter and an AC load; the inverter has three ports of input, output and energy storage, and has two working modes, and can convert the input DC source voltage or the single-stage high-gain boost of the battery into a stable, high-quality three-phase sinusoidal AC power; the control method is to centrally control the inverter and the battery charging and discharging control of the topology. The present invention improves the power density and efficiency of the energy storage system while improving the gain of the DC power supply; and adopts a control strategy to realize the bidirectional power flow between the ports, which can ensure the efficient operation of the energy storage system.

This utility model discloses a rotor lamination for a unipolar motor and the unipolar motor itself. The rotor lamination has at least two circumferentially spaced magnetic slots on its end face. The outer circumferential surface of the rotor lamination has a groove. Each magnetic slot has a groove at both ends, which are respectively the entry end and the exit end. The groove near the entry end is the first groove, and the groove near the exit end is the second groove. The width of the first groove and the second groove along the circumferential direction of the rotor lamination and / or the depth along the radial direction of the rotor lamination are different. By setting the width and / or depth of the first groove and the second groove to be different, the width of the permanent magnet pole face towards the air gap can be adjusted, thereby reducing the leakage magnetic flux at both ends of the permanent magnet pole. It also makes the magnetic flux density of adjacent magnetic poles more symmetrical, and can reduce the odd and even harmonics in the air gap magnetic flux density, thereby reducing the back EMF harmonic content and reducing torque ripple.

The invention belongs to the technical field of communication, and particularly discloses a low-harmonic low-frequency tuning matching transmitting system and a signal transmitting method thereof. The system comprises a cascade power amplification circuit and a tuning filtering matching circuit which are connected in sequence, the cascade power amplification circuit is used for processing the excitation signal into multiple paths of level driving signals and performing power amplification and synthesis on each path of level driving signal to generate a low-frequency signal with the power not smaller than target power; and the tuning filtering matching circuit is used for tuning and filtering the low-frequency signal, and adjusting the output impedance of the system and the input impedance of the antenna to reach an impedance matching state, so that the filtered low-frequency signal is transmitted in the impedance matching state. According to the invention, the harmonic content of the low-frequency signal can be effectively reduced, the low-frequency emission harmonic suppression performance of the maneuvering station is higher than the existing harmonic index, and the harmonic index of the maneuvering low-frequency communication system is effectively improved.

The invention provides a PWM wave optimization method and system based on VIENNA rectifier single-period control. The PWM wave optimization method comprises the steps that three-phase input current is sampled; determining the position of the corresponding PWM wave high level in the switching period according to the current direction of each phase; the method specifically comprises the following steps: for each PWM output channel, according to a phase current symbol associated with the PWM output channel, selecting to place a high level at two ends or in the middle of a switching period; and based on the determined PWM high level position and the calculated duty ratio, generating and outputting a PWM driving signal used for controlling a VIENNA rectifier switch tube. According to the method, PWM generation logic is redesigned, a non-optimal voltage vector combination used in traditional synthesis is abandoned, and three vectors (namely vectors corresponding to three vertexes of a small triangle where a target vector is located) closest to the target voltage vector are adopted for synthesis; according to the optimization, on the premise that the switching frequency is not increased and extra hardware cost is not increased, output current harmonics are remarkably reduced.

The present invention proposes a high-precision core loss measurement device with multiple input waveforms. The device includes a periodic square wave voltage generation module, a multi-waveform input generation module and a core loss measurement module. The periodic square wave voltage generation module generates a periodic square wave voltage, and the multi-waveform input generation module generates a variety of common voltage waveforms, and then generates current waveforms of different shapes on the primary winding of the magnetic core to be measured through different switch combinations and switch tube conduction timings. The core loss measurement module uses the inductance in the air-core transformer to partially compensate for the error amplification effect caused by the voltage and current phase angle difference caused by the inductance of the magnetic core to be measured. By calculating the compensation factor, the error caused under any input waveform is reduced to close to 0, thereby achieving high-precision measurement of the core loss. The present invention solves the problem of sensitivity to measurement phase error when measuring core loss using the dual-winding method, and can accurately measure the core loss at high frequencies.

The invention discloses a DPCC predictive control system and method for introducing a sliding mode component into a Luenberger observer. According to the system, a dead-beat current prediction controller generates predicted direct-axis voltage and quadrature-axis voltage according to given direct-axis current and quadrature-axis current and direct-axis current and quadrature-axis current fed back by a control system in combination with parameter disturbance; the three-state pulse width modulator generates six paths of pulse signals according to the predicted direct-axis voltage and quadrature-axis voltage; the inverter inverts the six paths of pulse signals to generate three-phase current; the control system controls the permanent magnet synchronous motor according to the three-phase current and obtains the actual output of the permanent magnet synchronous motor; and the Luenberger observer is used for generating parameter disturbance according to the actual output of the permanent magnet synchronous motor. According to the prediction control system, the tracking precision of the DPCC control system can be improved, the common-mode voltage can be reduced, the current deviation caused by parameter change can be inhibited, and the current deviation caused by motor parameter change can still be eliminated when the load is suddenly changed.

The invention discloses a rail holding type bilateral drive aerotrain system, and relates to the technical field of aerotrain systems. Decoupling of suspension, guiding and driving functions of the maglev train is achieved, the control complexity of the maglev train is reduced, and safe operation of the maglev train is guaranteed. The system comprises a vehicle body structure, an I-shaped supporting beam, a suspension system, a safety limiting and braking system and a driving system. The train body structure comprises a train and a suspension frame arranged at the bottom of the train. The suspension frame is of an inverted-U-shaped structure, and the upper flange and at least one part of a web of the I-shaped supporting beam extend into a cavity of the suspension frame. The suspension system is arranged between the top wall surface of the cavity of the suspension frame and the upper surface of the upper flange; the safety limiting and braking system is arranged between the side face of the upper flange and the side wall face of the cavity of the suspension frame. The driving systems are arranged between the side faces of the webs of the I-shaped supporting beams and the side wall face of the cavity of the suspension frame. The performance of the suspension driving system is improved.

The invention relates to the technical field of converter control, and discloses a model-free predictive current control method and device for an energy storage converter and a medium. According to the method, the first voltage candidate vector sequence and the second voltage candidate vector sequence of the sector where the corresponding reference voltage is located can be obtained, compared with a traditional symmetric double-vector scheme, the generalized double vectors are introduced, the better steady-state effect under the high modulation ratio can be obtained, and the harmonic content is greatly reduced. Finally, on the basis of considering a preset objective function of frequency control, a driving signal for each switching tube for controlling the current of the energy storage converter can be generated in combination with the first voltage candidate vector sequence and the second voltage candidate vector sequence. Therefore, by implementing the method, the steady-state performance of the model-free predictive control of the energy storage converter is effectively improved by combining the improved generalized symmetric double-vector modulation method with the model-free predictive control.

The invention provides a low-voltage power supply input inversion controller and a control method thereof, and relates to the technical field of power supply circuits, and the low-voltage power supply input inversion controller comprises a low-voltage power supply, a multi-level inverter and a fast terminal sliding mode controller; the low-voltage power supply, the multi-level inverter and the fast terminal sliding mode controller are sequentially connected in series; the multi-level inverter is used for converting direct current provided by the low-voltage power supply into alternating current and synthesizing an output voltage close to a sinusoidal waveform through a plurality of voltage levels; and the fast terminal sliding mode controller is used for assisting the output of the multi-level inverter to quickly reach a stable state. The rapid terminal sliding mode control is adopted to assist the output of the multi-level inverter to rapidly reach a stable state, rapid convergence of the system state can be realized in finite time, the multi-level inverter is adopted to convert the direct current provided by the low-voltage power supply into the alternating current, smoother sine waves can be generated, harmonic distortion is reduced, and the system stability is improved. The quality of output electric energy is improved.

The invention relates to the operation and a circuit arrangement (1) for a variable mains connection (single-phase / three-phase) with respect to the input voltage, which is connected to the neutral conductor (N) of the input AC voltage source via a connecting line (10) by means of a center tap (M) between capacitors (C).

The invention discloses a rotor, a motor, a compressor and refrigeration equipment, the rotor comprises a permanent magnet and a rotor iron core, the rotor iron core is provided with a plurality of structural groups, each structural group comprises a mounting groove and n slits, n is a positive integer, the permanent magnet is arranged in the mounting groove, and the slits are arranged in the mounting groove. The slits are located between the mounting grooves and the outer peripheral surface of the rotor core, the width of each slit is Ln, the width of each mounting groove is b, the total width of the n slits is Sigma Ln, Sigma Ln = L1 + L2 +... + Ln, and the relationship between Sigma Ln and b is 0.1 < = Sigma Ln / b < = 0.5. According to the technical scheme, the magnetic line trend can be optimized, magnetic leakage is reduced, the permanent magnet utilization rate is improved, and the motor efficiency is improved.

The invention provides an MMC optimal switch sequence model prediction control strategy based on output voltage space vector fitting. According to the strategy, coordinates of candidate vectors in a g-h coordinate system are calculated through vector predicted values according to a discrete prediction model of a three-phase MMC alternating current side output voltage space vector; obtaining an optimal switching sequence by screening redundant switching states of the candidate vectors; constructing a value function of an output current error sum of squares based on the current change gradient, and solving a partial derivative of the value function to obtain an optimal action time expression; calculating the optimal duty ratio of the bridge arm and the number of conducted sub-modules according to the bridge arm unbalanced voltage drop prediction model; and capacitor voltage balance of the sub-modules is realized through a sorting algorithm. The method has the advantages that compared with a traditional model prediction control strategy, the strategy is small in operation burden, the harmonic content of output current is effectively reduced, harmonic spectrum distribution is more concentrated, a universal algorithm for screening the optimal switching sequence of the multi-level converter is designed with MMC as an example, the method can be applied to any level, and the operation amount is not changed.

The invention discloses a method for compensating the installation error of the Hall sensor in a permanent magnet synchronous motor, comprising: firstly, using a constant voltage-frequency ratio control method to put the motor in a uniform speed operation state, and then dividing one cycle into six sectors through six rotor positions detected by the Hall sensor, and calculating an absolute reference position through a controller to correct the absolute deviation of three Hall sensors. The compensation amount is found through the obtained absolute deviation, thereby indicating the actual position of the rotor, and reflecting all the information of the absolute error by selecting three consecutive sectors, expressing the complete absolute position deviation correction equation by establishing a minimum variance estimation, and measuring the corresponding time by a timer of the controller to calculate the relative position deviation, thereby performing position compensation. This method can reduce the harmonic content of the current, improve the sinusoidality, accurately obtain the actual position of the rotor, and improve the sinusoidality of the current.

The utility model relates to a kind of motor rotor structure for realizing rotor flux better sinusoidal distribution, belong to motor technical field, including protective shell, the protective shell is located in rotor, the rotor and protective shell are equipped with stator, the rotor is equipped with magnetic separation slot and magnetic filling slot, the magnetic filling slot is inserted and embedded permanent-magnetic strip, the permanent-magnetic strip includes permanent magnet I, permanent magnet II and permanent magnet III. Permanent magnet I and permanent magnet II, permanent magnet III superposition realizes rotor flux better sinusoidal distribution. Permanent magnet I, permanent magnet II, permanent magnet III and magnetic separation slot jointly form cross-axis magnetic circuit, due to the formation of reluctance torque superposition, thereby increase torque. By optimizing rotor magnetic pole shape, permanent magnet arrangement and auxiliary structure are realized, to reduce harmonic content, improve torque stability. Realize the good sinusoidal distribution of rotor flux, low motor torque ripple and slot effect, to improve the stability of motor operation, efficiency and control accuracy.

The invention provides a power factor correction circuit adaptive control method and system, and the method comprises the steps: collecting an input voltage signal of a power factor correction circuit, obtaining a voltage control signal of the power factor correction circuit, and collecting a current sampling signal of the power factor correction circuit; the duty ratio of a switch driving signal is calculated based on the current sampling signal, the input voltage signal and the voltage control signal, the current sampling signal and the duty ratio are in a reverse growth relation, the input voltage signal and the duty ratio are in a reverse growth relation, and the current sampling signal and the input voltage signal are in a reverse growth relation. The voltage control signal and the duty ratio are in a homodromous growth relationship; and controlling the on-off of a switching device of the power factor correction circuit according to the duty ratio of the switching driving signal. According to the invention, the switch driving signal of the power factor correction circuit is adaptively adjusted based on the load change and the input voltage change, and the stable operation of the driven equipment is ensured.

The application discloses a three-level full-bridge dual active bridge converter and a midpoint potential balance control method. The converter comprises a high-frequency transformer, a DC input voltage source is arranged on the primary side of the high-frequency transformer, and series-connected upper and lower capacitors are connected between the positive and negative electrodes of the DC input voltage source. Three-level half-bridge A and three-level half-bridge B are connected in parallel, a node between the upper and lower capacitors is connected to the midpoint of two clamping diodes of the two three-level half-bridges, the center point of the three-level half-bridge A is connected to one end of the primary side of the high-frequency transformer through a power transmission inductor, and the center point of the three-level half-bridge A is connected to the other end of the primary side of the high-frequency transformer through a DC isolation capacitor. In the control method, the primary side power device is divided into a fixed 50% duty ratio basic bridge arm and a non-symmetrical duty ratio adjusting bridge arm, a PI voltage balance loop is constructed by taking the voltage difference of the two capacitors as feedback, the duty ratio of the adjusting bridge arm is dynamically adjusted, the average value of the midpoint current is changed, and the midpoint potential balance is realized.

The present invention provides a totem pole PFC inductor current correction method and system, comprising: adjusting the control coefficient of the PI current compensator in the control circuit and the change law of the high-frequency carrier amplitude; the adjusted control circuit generates a modulation wave; and the modulation wave is input into the power circuit to realize the correction of the inductor current waveform. The present invention realizes the correction and compensation of the inductor current waveform by changing the reference voltage and the control coefficient of the current regulator, so that the inductor current waveform is closer to a sine wave, and the current harmonic content is effectively reduced.