76 results about "Phase inductance" patented technology

The invention discloses a position sensorless control method for a switched reluctance motor, and belongs to the technical field of motor control. According to the method, current chopping control is carried out in a conduction interval, low-threshold chopping control is carried out in a non-conduction interval, and the current hysteresis width changes along with the rotation speed, so that the rotor position estimation precision when the rotation speed is increased is ensured. According to the method, current information of each phase is collected, a current slope difference value is calculated, three-phase inductance is obtained through calculation according to the current slope difference value, the inductance obtained through calculation is compared with a preset inductance threshold value, and on-off signals of each phase and pulse signals of special position points can be obtained. According to the time interval between the rising edges of the adjacent position pulse signals and the corresponding rotor position angle difference value, the real-time rotating speed of the motor is obtained through calculation, and the motor rotor position at any moment is estimated. The method is simple in structure and convenient to implement, is not affected by inductance saturation, and is high in position estimation reliability and universality.

An automatic current sharing control method for an interleaved BUCK converter belongs to the technical field of power electronics, and comprises the following steps: step S1, obtaining an output voltage and a given output voltage of a load end of the interleaved BUCK converter; obtaining the current of each phase of inductor; s2, obtaining an average value of the inductive current of each phase, and averaging the average value of the inductive current of each phase as a reference value of a current loop; s3, calculating a duty ratio signal through a current loop; s4, calculating a duty ratio signal through a voltage loop; and S5, superposing the duty ratio signal of the current loop operation of each phase with the duty ratio signal of the voltage loop operation. According to the invention, the inductive current of each phase follows the average inductive current of three phases in real time, high-precision current-sharing control is realized, and the control reliability is improved, so that the output current is controlled at an average level.

The utility model relates to motor driver test technical field discloses motor driver test load and motor driver testing arrangement, the motor driver test load includes: three -phase inductance load, three -phase inductance load includes a plurality of three -phase test end, wherein, the load between each three -phase test end is different, the motor driver to be tested is connected with target three -phase test end of three -phase inductance load, carries out the test based on target three -phase test end corresponding load, temperature sensor sets up in three -phase inductance load, gathers three -phase inductance load's temperature signal and exports, control unit is connected with temperature sensor, receives temperature signal, and when temperature signal is higher than temperature threshold value, exports cooling signal, cooling unit sets up in three -phase inductance load, cooling unit is connected with control unit, receives cooling signal and starts and reduces three -phase inductance load's temperature. The utility model solves the problem that the existing test motor driver's load commonality is low.

The invention relates to a method, a device and equipment for determining the operation condition of a switched reluctance motor. The method includes obtaining a first data set of phase inductance, phase current, and rotor angle for the switched reluctance motor. The method further includes expanding the first data set into a second data set by the neural network model, the phase inductance in the second data set being associated with the flux linkage of the switched reluctance motor, the flux linkage being used to determine the operating condition of the switched reluctance motor. Through the mode, the data sets of the phase inductance, the phase current and the rotor angle can be expanded based on the neural network model, the situation that only the switched reluctance motor is observed to collect data is avoided, the data size of the data sets is increased, the collection cost of the data sets is reduced, and therefore the accuracy of the flux linkage and the operation condition is improved; and thus, the control accuracy of the switched reluctance motor is improved.

The utility model provides a single-phase inductor insulation resistance test fixture, the whole test fixture is of a hollow cuboid structure, and a single-phase inductor is placed in the test fixture; the single-phase inductor comprises two terminal endpoints and a middle magnet, probes are arranged at the positions, corresponding to the two terminal endpoints, of the top and the bottom of one side face of the testing jig, conducting layers making contact with the magnet are arranged on the inner walls of the two side faces of the testing jig, the conducting layers on one sides of the terminal endpoints transversely penetrate through the side faces, and the conducting layers on the other sides of the terminal endpoints transversely penetrate through the middle magnet. The other side surface is fully covered with a conductive layer; connecting wires are led out of the probe and the conductive layer and are inserted into insulation resistance testing equipment. According to the utility model, through the structural design of the test tool, especially the arrangement of the conductive layer, the insulation resistance of the inductor can be tested at one time, so that the test efficiency can be improved, the test accuracy can be improved, and the risk that defective products flow out is greatly reduced; the jig is simple in structure, convenient to use and wide in application range, and the test difficulty can be reduced.

The invention relates to the technical field of buck-boost converters, and discloses a phase control circuit and method, and a buck-boost system. According to the phase control circuit provided by the embodiment of the invention, the edge change rate of the phase-cut inductive current is slowed down by processing the phase-cut signal, so that when the double-phase reverse buck-boost converter performs phase cutting based on the phase-cut signal, one single-phase buck-boost converter can enter or exit softly, and the other single-phase buck-boost converter can enter or exit softly. Therefore, the ripple of the load voltage signal at the output end of the dual-phase reverse buck-boost converter is ensured to meet the design requirement, and the load connected with the dual-phase reverse buck-boost converter is prevented from working abnormally.

This invention belongs to the field of power electronics and electric vehicle charging technology, and discloses a bidirectional electric vehicle charger topology, control method, and system, including a grid-side module, an AC-DC module, and a DC-DC converter. The grid-side module includes a three-phase power supply from the grid, a first-phase resistor Rga, a second-phase resistor Rgb, and a third-phase resistor Rgc. The AC-DC module includes a power switching transistor group, a first capacitor C1, and a second capacitor C2. The three-phase output terminals of the grid power supply are respectively connected to the first-phase inductor Lga, the second-phase inductor Lgb, and the third-phase inductor Lgc. This invention eliminates the need for additional filtering hardware, reducing manufacturing costs, physical size, and system complexity, while improving power density and reliability. It can accurately locate and specifically compensate for critical harmonics of specific orders in the power grid, and can quickly and in real-time track and suppress dynamically changing harmonics and transient disturbances.

The application discloses a kind of three-phase rectifier multiple switch tube open-circuit fault diagnosis methods based on voltage deviation, belong to power electronic converter fault diagnosis technical field.Method includes: obtaining relevant signal for diagnosis;According to three-phase voltage, three-phase current, three-phase inductance value, three-phase equivalent resistance value and switching period, the actual value of three-phase line voltage is calculated;According to DC voltage and the duty cycle of switch tube on three-phase bridge arm, the expected value of three-phase line voltage is calculated;Difference is obtained between the expected value and actual value of three-phase line voltage;The deviation value of three-phase line voltage is compared with first preset threshold and second preset threshold, to determine the polarity of the deviation value of three-phase line voltage;Wherein, first preset threshold is less than second preset threshold;The polarity of the deviation value of three-phase line voltage is combined with voltage phase, to determine fault switch tube.The application can quickly diagnose for various situations of multiple switch tube fault, including single switch fault, two switch tubes in succession fault, two switch tubes simultaneous fault.

The application provides a vertical-axis phase-synchronous pulse injection control method for a hybrid excitation variable reluctance motor, and belongs to the technical field of motor control. The method comprises the following steps: S1, configuring a hybrid excitation variable reluctance motor, which comprises two sub-phase components, and each sub-phase component is powered by a three-phase four-bridge-arm inverter; S2, constructing a self-induction model under pulse detection signal excitation based on the structure of the hybrid excitation variable reluctance motor; S3, sequentially injecting detection pulse voltages into each phase by adopting the vertical-axis phase-synchronous pulse injection method, obtaining the size of the inductance value of each phase, thereby judging the current sector where the rotor is located, and substituting the bias electric angle into the self-induction model to calculate the bias electric angle; and S4, calculating the electric angle of the rotor magnetic field at the current moment according to the bias electric angle.

The present invention discloses an overcurrent protection method and system for a vehicle-mounted inverter, relating to the field of inverter technology. The method comprises: step 1: within a single pulse width modulation cycle, performing multiple rapid sampling of the output current of the shunt resistor of the vehicle-mounted inverter to obtain a phase current estimate that is closer to the true instantaneous phase current; step 2: constructing a transient overcurrent risk index based on the phase current estimate, combined with the motor phase inductance, DC bus voltage, and the motor's electrical time constant; step 3: using the nominal rated current as a reference, adaptively adjusting the trip threshold according to the transient overcurrent risk index; and step 4: activating soft shutdown logic to perform overcurrent protection on the vehicle-mounted inverter based on the transient overcurrent risk index and the phase current estimate. The present invention significantly improves the accuracy and sensitivity of overcurrent protection, achieving intelligent quantitative risk assessment and dynamic adaptation of protection boundaries.

The invention discloses a pre-synchronization grid-connection method for a grid-construction type converter under an unbalanced power grid, and the method comprises the steps: 1, obtaining the positive-sequence components and negative-sequence components of three-phase grid-connection point voltage, three-phase output current, three-phase output voltage and three-phase inductive current; step 2, determining the positive sequence amplitude and the negative sequence amplitude of the grid-connected point voltage; step 3, generating a negative sequence voltage given value of the network construction type converter; step 4, determining a positive sequence voltage given value, a positive sequence voltage frequency value and a positive sequence voltage phase value of the network construction type converter; 5, performing double-loop control of positive sequence voltage and positive sequence current and double-loop control of negative sequence voltage and negative sequence current on the voltage output by the grid-forming converter and the positive sequence component of the inductive current; and step 6, judging whether a grid connection condition is met, and if yes, ending pre-synchronization. The problem of failure of pre-synchronization grid connection of the grid-forming converter under the three-phase unbalanced power grid is solved.

The application discloses a four-phase different-name end coupling magnetic integrated inductor, which comprises an upper cover plate, a lower cover plate, four magnetic columns and four windings; the upper cover plate and the lower cover plate are of the same shape, and the four magnetic columns are of the same shape; the four magnetic columns are uniformly distributed in a horizontal direction around a vertical connecting line of a center point of the upper cover plate and a center point of the lower cover plate; the upper cover plate covers upper surfaces of the four magnetic columns, and the lower cover plate covers lower surfaces of the four magnetic columns; the four-phase different-name end coupling magnetic integrated inductor further comprises a partition air gap; the four windings are of the same structure and are wound on the four magnetic columns respectively to form four-phase inductors which are magnetically coupled; after current excitation is applied to the four windings, magnetic fluxes generated in the four magnetic columns are of the same direction. The four-phase winding different-name end coupling makes the magnetic fluxes generated in the upper cover plate of the magnetic core and the lower cover plate of the magnetic core have the same direction, so that the four-phase inductors can be reduced to a certain extent. The four-phase different-name end coupling magnetic integrated inductor is favorable for reducing inductance current ripple and in turn reducing winding loss, and can improve current uniformity and rated value of the four-phase inductors.

The invention discloses a three-phase switched reluctance motor torque control method based on alignment position detection, and relates to the technical field of motor control. Injecting a high-frequency current pulse into a non-conducting phase of which the inductance is monotonically changed along with the position in each position sector taking two adjacent aligned positions as end points, and ensuring that the non-conducting phase has no tail current before injection; estimating the inductance of the non-conducting phase according to the rising slope of the high-frequency current pulse injected into the non-conducting phase or the falling slope of the trailing current; if the inductance is smaller than the preset threshold value, instantaneous torque control based on a torque distribution function is adopted according to the inductance estimation position; otherwise, not estimating the position, neglecting the change of the conduction phase torque along with the position, and determining the conduction phase given current according to the current-torque characteristic at the 60-degree electrical angle position. As only the alignment position needs to be detected and the instantaneous torque control area is expanded, compared with the technology that instantaneous torque control is adopted only in the two-phase conduction area, the cost of the position sensor can be reduced, and torque pulsation can be restrained.

The invention discloses a switched reluctance motor sliding mode control-torque distribution function control system and method, and relates to the field of switched reluctance motor control. The change of the change rate of phase current is caused along with the change of phase inductance when the switched reluctance motor runs, and the change of the torque tracking capability of the previous phase and the next phase is caused, so that the torque compensation is carried out according to the change of the torque tracking capability of the previous phase and the next phase, the traditional sine type torque distribution function is improved, and the torque pulsation of the motor is reduced. According to the method, an off-line optimization control strategy and an on-line optimization control strategy are also provided to optimize the opening angle, so that the phase current peak value is reduced while the torque ripple of the motor is suppressed.

This utility model discloses a three-phase inductor, including a three-phase magnetic core structure, corresponding winding structures, and lower and upper mounting brackets respectively disposed at the upper and lower ends of the three-phase magnetic core structure. The lower mounting bracket is provided with a first positioning component that positions and cooperates with the bottom of each phase magnetic core, which is composed of multiple lower positioning plates arranged circumferentially around the bottom of the magnetic core. The upper mounting bracket is provided with a second positioning component that positions and cooperates with the top of each phase magnetic core, the second positioning component including an upper positioning cover that covers the top of the magnetic core. By connecting the upper and lower mounting brackets through multiple sets of locking components and applying opposing overall clamping forces, the magnetic core is rigidly fixed. The three-phase inductor with this structure design effectively ensures the coaxiality of the three-phase magnetic core by synchronously constraining the radial movement and axial displacement of the magnetic core structure through bidirectional positioning, ensuring the stable electrical performance of the inductor, improving production and assembly efficiency, and saving installation space.

The invention discloses an optimal control method and system for a bipolar AC-AC converter under three-phase inductance asymmetry. The bipolar AC-AC converter is of an ABC three-phase structure, each phase comprises an upper bridge arm and a lower bridge arm which are the same, each of the upper bridge arm and the lower bridge arm comprises n full-bridge sub-modules and a bridge arm inductor which are connected in series, and the three-phase bridge arm inductors are different. The control method provided by the invention comprises three parts: firstly, suppressing power frequency negative-sequence current to be 0 in a dq coordinate system on a power frequency side, secondly, suppressing low-frequency negative-sequence current to be 0 in the dq coordinate system on a low-frequency side, and thirdly, eliminating three-phase capacitor voltage difference to be 0 in an alpha-beta coordinate system. Through negative sequence control and capacitor voltage balance control strategies, optimal control of the bipolar AC-AC converter under the condition of asymmetric three-phase inductance parameters is realized, suppression of negative sequence current and balance of capacitor voltage are realized, the running consistency of three-phase bridge arms is effectively maintained, and the reliability of the three-phase bridge arms is improved. And the safe operation capability of the bipolar AC-AC converter is improved.

The invention belongs to the technical field of inductance equipment manufacturing, and particularly relates to a three-phase inductance coil winding device and method. Comprising a base, and a driving roller and two driven rollers are mounted at the top of the base; a magnetic ring is connected between the driving roller and the two driven rollers in an abutting mode. A first electric telescopic rod is further installed at the top of the base and located below the magnetic ring, and a wire hook is fixedly arranged at the end of the first electric telescopic rod. According to the invention, the problems of complex process and low efficiency caused by repeated winding and repeated cutting during preparation of the three-phase inductance coil can be avoided through one-time forming, and meanwhile, the magnetic ring is not damaged; the device can quickly adapt to the size change of the magnetic ring and the operation of the rollers, the problem that the magnetic ring cannot rotate due to inaccurate adjustment caused by respective adjustment of the rollers is solved, the device can be quickly reset, and the fine adjustment efficiency is greatly improved; the multi-coil winding and cutting device is suitable for large-current multi-coil winding and cutting at the same time.

The invention provides a power supply system and a power supply method. In one embodiment, the power supply system includes a first rectifier filter, a second rectifier filter, and a power management module. The first rectifier filter is connected to a first winding and is used for providing an output power supply. The second rectifier filter is connected to an auxiliary winding for providing an auxiliary power supply. The auxiliary winding is inductively coupled with the first winding. The number of turns of the first winding is greater than the number of turns of the auxiliary winding. The power management module is connected to the auxiliary power supply and the output power supply, and selects or does not select the output power supply as an input power supply according to one of an operation power supply and the output power supply. The input power supply is used for enabling the power management module to generate and regulate the operation power supply.

The application discloses a kind of non-fault phase continuous power supply three-phase inverter short-circuit current limiting method and system, belong to independent power supply system protection control field.The system described in the application includes normal control system and fault control system, normal control system includes capacitor voltage outer ring, fault control system includes non-fault phase capacitor voltage outer ring and adaptive phase angle adjusting link based on SOGI filter, both are connected with inductance current inner ring by switching module.The application has the advantages of fast current limiting response speed, simple control structure compared with existing strategy.When asymmetric fault occurs, the output current of fault phase can be maximized and the reliable power supply of non-fault load of the system can be ensured.The application can adaptively change the phase angle between fault and non-fault inductance current, which can make the inverter always meet the system power supply and current limiting requirements with good robustness.

The present invention discloses a method for obtaining d-q-0 axis inductance parameters of an open-winding permanent magnet synchronous motor, comprising the following steps: S101, short-circuiting U, V, and W terminals of the open-winding permanent magnet synchronous motor; S102, passing low-voltage direct current between phases A and B of the motor to lock the angle between the rotor reference axis and the stator A-phase axis. After the angle between the rotor reference axis and the stator A-phase axis is locked, cutting off the power supply; S103, measuring the phase inductance of the stator three-phase winding; S104, measuring the line inductance of the stator three-phase winding; S105, calculating the mutual inductance between the three-phase stator winding; S106, obtaining a relationship between the three-phase winding flux linkage and the d-q-0 axis inductance based on a mathematical model of the open-winding permanent magnet synchronous motor; and S107, applying coordinate transformation theory to derive an expression for the d-q-0 axis inductance represented by the phase inductance and the line inductance, and substituting the expression into the measured data to obtain the d-q-0 axis inductance.

The invention discloses a low-ripple hydrogen production power supply based on a pseudo-continuous multi-phase interleaving parallel converter, which relates to the technical field of water electrolysis hydrogen production and comprises a direct-current power supply, an electrolytic bath, a three-phase interleaving parallel Buck power unit and three pseudo-continuous follow current branches, the three pseudo continuous follow current branches are respectively connected between three-phase switch nodes and output ends of the three-phase staggered parallel Buck power unit, and the pseudo continuous follow current branches adopt follow current switch devices and are used for conducting and connecting the switch nodes and the output ends in a follow current stage, so that voltages at two ends of a phase inductor are approximately zero; and the input end and the output end of the three-phase interleaving Buck power unit are respectively connected with a direct-current power supply and an electrolytic bath. Wide-working-condition low-ripple output can be achieved under the condition that the size of the output filter is not remarkably increased, the operation efficiency of the electrolytic cell is improved, the service life of the electrolytic cell is prolonged, and the requirements of a large-scale hydrogen production system for a high-reliability and high-efficiency power source are met.

The invention discloses a metal magnetic powder core structure for a staggered high-frequency inductor, which is characterized in that the staggered high-frequency inductor adopts a staggered parallel topological structure, the phases of current are mutually staggered, and current ripples can be mutually counteracted, so that the current ripples in a circuit are effectively reduced. For example, in a double-phase cross coupling inductor, the phase difference of two paths of current is 180 degrees, current ripples can be greatly reduced, a plurality of inductors can be connected in parallel, the current borne by each phase of inductor is reduced, and then inductance elements with small sizes can be selected. The device has a series of advantages of miniaturization, low electromagnetic interference, high reliability and the like.

The utility model relates to the technical field of single-phase inductors, in particular to a single-phase inductor with a cooling structure, which comprises an iron core, a coil is wound on the outer ring of the iron core, heat conducting discs are integrally formed at two ends of the iron core, a water tank is fixedly connected to two ends of the iron core, the heat conducting discs are arranged in the water tank, and the cooling structure is arranged in the water tank. And the middle part of the water tank is rotationally connected with a connecting shaft. According to the improved single-phase inductor, external air enters the inductor shell through the heat dissipation holes and is discharged out of the heat dissipation holes in the other side, heat in the inductor shell is taken away through air circulation, air cooling is achieved, the motor is started, the motor drives the impeller to rotate through the connecting shaft, cooling liquid flows between the two water tanks, and cooling is achieved. The heat of the iron core is circularly taken away, and when the cooling liquid passes through the return pipe, the heat is dissipated into the air for cooling, so that the temperature of the cooling liquid can be ensured not to be too high even in a long-time working state, and the cooling effect is not reduced.

The application discloses a sensor multiplexing current tracking control method and device and related equipment, and the method comprises the following steps: acquiring a reference current output by a measured transformer, and collecting total inductance currents of n-phase interleaved transformers; the total inductance current is the sum of all inductance currents corresponding to n parallel half-bridge circuits; calculating a total current error between the total inductance current and the reference current; for each phase in the n phases, based on the total current error and the actual sampling value of the inductance current, a coupling reference value corresponding to the inductance current of each phase is generated; according to the coupling reference value, the duty cycle of the lower switch in each phase half-bridge circuit is calculated; based on the duty cycle calculated for each phase, the on-off state of the upper switch and the lower switch of the corresponding phase half-bridge circuit is controlled respectively, so that the total inductance current tracks the reference current. By introducing the coupling reference value based on the total current error, the current tracking speed and accuracy of the multi-phase interleaved transformer are improved.

The invention relates to the technical field of power electronic technology simulation modeling, and discloses a new energy converter modeling method and device, and the method comprises the steps: building a primary topological structure diagram of a converter in a mode of replacing the converter with a controlled voltage source; based on the energy balance relation of the flexible DC converter, virtual DC bus voltage is constructed; based on the electrical parameters of the primary topological structure and the virtual direct current bus voltage, a three-phase modulation wave is obtained in a closed-loop control mode; and after the three-phase modulation wave is subjected to delay control, a control signal of the controlled voltage source is obtained. According to the new energy converter modeling method, a controlled voltage source is used for replacing a traditional switching device, a nonlinear link of the model is removed, the simulation calculation amount is greatly reduced, the simulation step length can be increased, the simulation speed of a large-scale new energy station current collection system is remarkably increased, and the situation that the simulation software electrical node containing limit is exceeded is avoided. Meanwhile, the filter circuit is simplified into a three-phase inductance structure, electrical nodes are further simplified, and system-level integration simulation requirements are met.

The utility model discloses an inductance structure and a power converter, which comprises a plurality of phases of windings and an internal magnetic core positioned in each phase of winding, and one end of each internal magnetic core is connected to the same common magnetic core. According to the utility model, the end side of each phase of inductance magnetic core is connected to the same common magnetic core, and the magnetic resistance of the common magnetic core is far smaller than the air magnetic resistance, so that the original leakage flux between two phases of windings is absorbed by the common magnetic core, that is, the leakage magnetic field intensity on the outer side of the common magnetic core is greatly reduced, and the electromagnetic influence on external devices is avoided. The projection outline of the common magnetic core is tangent to the outline of the internal magnetic core, so that the size of the common magnetic core is reduced under the condition that leakage flux is reduced as much as possible and the operation reliability of a circuit is improved, and the cost is saved.

The utility model discloses a testing device for a three-phase inductor, and relates to the technical field of inductor testing. The device comprises a base and a material receiving drawer, the material receiving drawer is arranged in the base, clamping type placing assemblies are fixedly installed on the two sides in the base, a three-phase inductor body is fixedly clamped in the clamping type placing assemblies, a fixing frame is fixed to the top of the base, and a sliding groove is formed in the inner wall of the top of the fixing frame. A detachable mobile test assembly is fixedly installed on one side in the sliding groove. According to the utility model, through the clamping type placing assembly, three-phase inductor main bodies of different models can be clamped and fixed, the test accuracy is guaranteed, unqualified three-phase inductor main bodies can be rapidly removed, a plurality of three-phase inductor main bodies can be tested by using the detachable mobile test assembly, and the test efficiency is improved. The testing efficiency is improved, the testing head can be disassembled, assembled and replaced, and the use is more convenient.

The invention discloses a power system subsynchronous resonance energy recovery device and method, and belongs to the technical field of power systems. The device comprises a band-pass filtering unit, a bypass switch unit, a three-phase monitoring unit, a control unit, a three-phase thyristor full-bridge circuit and a three-phase inductance energy storage module. The band-pass filtering unit is connected in parallel to a unit outlet bus, and the bypass switch unit is connected in parallel to two ends of the filtering unit to realize time-sharing switching; and the control unit identifies resonance according to the monitoring signal and controls the thyristor full-bridge circuit to be switched between a rectification mode and an inversion mode. The method comprises the following steps: bypass filtering in standby, and monitoring power frequency; when resonance exceeds a threshold value, filtering and rectifying energy storage are carried out; after resonance is eliminated, bypass filtering is carried out, and inversion feedback energy is sent to a power grid. According to the invention, through cooperation of the pre-filtering and the bypass switch, precise detection, rapid suppression and energy loss-free recycling of subsynchronous resonance are realized, and the system economy and the equipment reliability are greatly improved.

The application discloses a high-frequency AC coupling-based flexible interconnection switch structure of a medium-high voltage AC-DC hybrid power distribution network, which comprises two groups of high-frequency AC coupling type modular multilevel converters and a phase-shifted inductor. Each group of the modular multilevel converters adopts a three-phase six-bridge-arm structure and has three power ports of medium voltage DC, medium voltage AC and high-frequency AC; a sub-module of the modular multilevel converter adopts a half-bridge structure; an isolation stage is formed by a full-bridge module and a high-frequency transformer to form a high-frequency AC bus in an AC form at the output end of the high-frequency transformer of each sub-module, so that the coupling offset of low-frequency fluctuation current of the sub-module and the autonomous clamping of the capacitor voltage are realized, and the capacitor volume of the sub-module and the system control strategy are greatly optimized. The phase-shifted inductor is connected between the high-frequency AC buses of the two groups of the modular multilevel converters to form a double active bridge converter structure, and through high-frequency coupling, bidirectional energy transmission between two different voltage grade AC power grids with different working frequencies can be realized. The application can realize the flexible interconnection of the medium-high voltage AC power distribution network, has the advantages of sub-module capacitor voltage self-balancing, high power density and simple control structure.

The embodiment of the invention discloses a heating control method and device of a power battery and a vehicle, the method is applied to an alternating current heating system, the system comprises the power battery, a capacitor, inductance windings of a three-phase motor and a three-phase inverter, and any phase of inductance winding in the three-phase motor serves as a battery connecting phase; the battery connection phase is connected with the power battery through a first relay, and a second relay is arranged between the battery connection phase and the three-phase inverter; the method comprises the steps that a first relay is controlled to be switched on, a second relay is controlled to be switched off, a charging and discharging loop is formed, and the charging and discharging loop comprises an inductance winding of a three-phase motor, a three-phase inverter, a power battery and a capacitor; and controlling a charging and discharging loop to form charging and discharging current based on the rotor angle of the three-phase motor so as to heat the power battery. The power battery is heated under the condition that an independent heating circuit is not additionally arranged, so that the heating cost is reduced.