1728 results about "Rectiformer" patented technology

The invention relates to a dual three-phase permanent magnet synchronous generator rectification system and a direct current voltage stabilization control method thereof. Comprising a dual three-phase permanent magnet synchronous generator, a VSD decoupling converter, a load current observer, a dynamic load feed-forward compensator, a voltage closed-loop controller, a dead-beat predictive current controller, a maximum four-vector SVPWM modulation module and a six-phase rectifier. The double-three-phase topological structure adopted by the invention has the advantages of multiple control degrees of freedom, high reliability and the like. A dynamic load feed-forward compensator is constructed to perform dynamic feed-forward compensation on quadrature-axis current of the motor, so that the recovery time of bus voltage is shortened, and the voltage fluctuation amplitude is reduced; the designed dead-beat predictive current controller optimizes the dynamic characteristics of a current loop, improves the torque tracking performance of the motor, and further improves the voltage stabilization regulation capability of the system. The designed load current observer realizes the analysis redundancy of current detection and improves the reliability of the system.

The invention discloses an output conversion system and method for a UPS (Uninterrupted Power Supply), and the system comprises a main power input end which is connected with a bridge rectifier through a first electromagnetic relay; the energy storage module comprises a super capacitor group and a parallel lithium battery group, and is coupled with the bus capacitor through a bidirectional DC / DC converter; the input end of the multi-path regulation and control module is connected with the bus voltage sensor, and the output end is connected with the switching execution unit through a second electromagnetic relay group; the dynamic switching unit comprises an I-GBT matrix and a reverse blocking diode array which are respectively connected with the inverter and the bypass circuit in parallel; and the real-time monitoring module is provided with a current harmonic analysis unit and a load break variable detection unit, and the output end of the real-time monitoring module is connected with the ADC port of the central processor. According to the invention, systematic improvement is realized in three dimensions of electric energy quality guarantee, equipment reliability and dynamic response capability through an original multi-path regulation and control architecture and a deep cooperative intelligent control strategy.

The invention provides an impedance scanning device based on network side voltage dynamic compensation under a three-phase voltage imbalance working condition, and relates to the technical field of new energy station power electronic converter topology and control, the device comprises a three-phase rectifier, a direct current bus capacitor, an inverter, a voltage compensation device, a frequency sweeping device, a circuit breaker and a series transformer part, the three-phase rectifier is connected in series with inverters of the voltage compensation device and the frequency sweep device, a secondary side of a series transformer of the voltage compensation device is connected in series with a network side, a secondary side of a series transformer of the frequency sweep device is connected in series with a grid-connected point, and a primary side of the series transformer is connected to the inverters and is coupled to a secondary side of the series transformer; according to the device, the power grid side voltage is rectified through the voltage compensation unit and is compensated to the grid side after being subjected to single-stage inversion transformation, voltage compensation is achieved through the energy of a power grid when the voltage is unbalanced, and an external energy source or an interference source does not need to be introduced. After compensation, the accuracy of the frequency sweeping result is obviously improved.

The invention discloses an intelligent charging pile core module based on a VIENNA structure, an electric energy quality management method, system and equipment and a storage medium, and belongs to the field of electric power system energy storage equipment.The intelligent charging pile core module based on the VIENNA structure comprises the steps that an integrated power conversion unit is constructed, the power conversion unit adopts a VIENNA rectifier topology, three-phase alternating current is converted into direct current, and the direct current is converted into direct current; a harmonic suppression structure linked with the control interface is arranged; state information in the operation process is collected and serves as input of the control strategy module; based on the state information, a modulation control instruction is generated in the control strategy module to drive the switching action of the power conversion unit; on the basis of the modulation control instruction, the switch control is executed, meanwhile, the direct-current side midpoint potential of the power conversion unit is synchronously adjusted, and the distribution of direct-current bus capacitor voltage is controlled; and identifying the current operation condition according to the state information, switching to a control template corresponding to the operation condition in the control strategy module, and generating a modulation control instruction.

The invention provides a single-phase four-quadrant rectifier IGBT open-circuit fault diagnosis method under multiple working conditions, and relates to the technical field of IGBT fault diagnosis. Historical data of alternating current side voltage, alternating current side current and direct current side voltage of the single-phase four-quadrant rectifier are obtained, and a total harmonic distortion rate threshold value, a direct current side voltage threshold value and an alternating current side current first threshold value are obtained. And constructing and training an IGBT open-circuit fault positioning identification model. Detecting the total harmonic distortion rate of the alternating-current side current of the single-phase four-quadrant rectifier in real time, if the total harmonic distortion rate exceeds a threshold value, entering fault positioning, collecting and calculating the average value of the direct-current side voltage and the alternating-current side current in the period, and judging the fault of the single-phase four-quadrant rectifier under the specific working condition according to the comparison of the average value and the threshold value. Or using an IGBT open-circuit fault positioning identification model to diagnose the fault; if the threshold value is not exceeded, the next period is continuously monitored. According to the invention, the IGBT fault diagnosis efficiency and accuracy of the single-phase four-quadrant rectifier are improved.

A system comprises: a high voltage (HV) direct current (DC) to DC converter (HVDC) including: one or more transformers; a bridge driver connected to a primary side of the one or more transformers; and one or more bridge rectifiers connected to a secondary side of the one or more transformers, the one or more bridge rectifiers including one or more bridge rectifier switches; a low voltage (LV) DC to DC converter (LVDC) connected to the HVDC; and a boost converter including: an inductor connected to the one or more bridge rectifier switches; and one or more boost configuration switches operable, in combination with the one or more bridge rectifier switches, to configure the boost converter into each of a bypass configuration and a boost configuration, to regulate a voltage at the LVDC.

A marine AC generator system includes a marine generator driven by an internal combustion engine and configured to generate an AC current and a rectifier configured to rectify the AC current to provide a DC current. At least one battery is configured to receive and be charged by the DC current. A battery powered inverter is configured to be powered by the at least one battery and to generate a variable current output frequency such that an AC electrical power is provided to a load when the marine generator is not running.

The invention discloses a hybrid direct current transmission power coordination control device and a control method and equipment thereof, and relates to the technical field of offshore power generation, and the hybrid direct current transmission power coordination control device comprises a diode rectifier unit and a first modular multilevel converter which are connected with an offshore wind plant, the sending-end converter station is used for converting alternating current generated by an offshore wind plant into direct current and outputting the direct current; the second modularized multi-level current converter is connected with the diode rectifier unit and the land power grid and is used for restoring the direct current into the alternating current and transmitting the alternating current to the land power grid; and the control module is connected with the first modular multilevel converter and is used for controlling the DC voltage of the first modular multilevel converter based on the fluctuation power according to the transfer relation between the active power and the DC voltage of the sending end converter station, so that the higher requirement of the rated capacity of the MMC in the related technology is met, and the reliability of the MMC is improved. And the engineering construction cost is increased.

The application discloses a kind of water electrolysis hydrogen production rectifier transformer harmonic active inhibition optimization method, comprising the following steps: constructing rectifier circuit, rectifier circuit includes switch tube, the voltage vector and zero vector of switch tube output are combined, and combined output voltage vector is obtained;The harmonic amplitude is obtained by processing combined output voltage vector, Levy tangent flight strategy and confidence domain variation strategy are introduced in black-winged kite optimization algorithm to construct improved dynamic search algorithm, the total harmonic distortion is obtained by iterative calculation of harmonic amplitude by improved dynamic search algorithm, i.e. optimal switch tube combination, the switch tube of rectifier circuit is adjusted by optimal switch tube combination, and the total harmonic distortion of rectifier circuit is reduced.The optimal switch tube combination of rectifier circuit is iteratively calculated by improved dynamic search algorithm in the application, effectively reduces resource consumption, and processing speed is accelerated, and the efficiency and accuracy of electrolytic water hydrogen production rectifier are improved.

An electric vehicle charging system comprising a Direct Current (DC) distributor, a site controller, one or more alternating current (AC) / DC rectifiers connected to the DC distributor and the site controller, and an electric vehicle charger having one or more DC / DC converters connected to the DC distributor and a charge controller in communication with the site controller and each of the one or more DC / DC converters. The one or more AC / DC rectifiers are decoupled from the one or more DC / DC converters.

The invention discloses a finite set model prediction direct power control method for a single-phase three-level rectifier. The method comprises the following steps: carrying out SOGI conversion on alternating current side voltage and current of the single-phase three-level rectifier and output voltage of the rectifier to respectively obtain two-phase orthogonal rotating vectors; calculating to obtain active power and reactive power according to the rotation vector; performing finite control set model prediction control through the calculated active power and reactive power and the rotating vector output by the SOGI, circularly traversing the switching state vector, and predicting the active power and reactive power rate at the next moment and the voltage difference between the upper capacitor and the lower capacitor at the direct current side; and finding out an optimal switching state through cost function calculation to control the three-level rectifier. According to the invention, faster dynamic response can be realized, and the method is especially suitable for a system with transient load disturbance; the FCS-MPC is easy to add system constraints, so that the robustness to power grid fluctuation and load fluctuation is higher; and the influence caused by uncertain factors such as external interference and model errors is reduced.

The invention discloses a variable frequency motor load testing device and method, and relates to the technical field of variable frequency motor testing, and the device comprises a motor testing installation platform, a fastening T-shaped bolt, two variable frequency speed regulation asynchronous motors of the same model, a drum-shaped coupler, two inverters, a rectifier, a three-phase voltage regulator, a frequency converter and an intermediate DC link. According to the invention, two frequency conversion speed regulation asynchronous motors of the same model are coaxially connected, and the power generation electric energy of the accompanying test motor is fed back to an intermediate direct current link through an inverter, so that the cyclic utilization of the electric energy and the dual-motor structural design are realized, complex load equipment does not need to be configured, and the fixed asset investment is reduced; for motors of different models, only corresponding accompanying test motors need to be replaced, the universality is improved, through voltage and current monitoring in an intermediate direct current link and motor rotating speed and torque parameter collection, and by combining a multi-dimensional performance evaluation model, precise evaluation of the motor load performance is achieved, the test efficiency is improved, and the strict test requirements are met.

The invention discloses a multi-line electric energy quality management and power flow transfer device and a control method, the device comprises a first regulation and control module, a second regulation and control module and a shared direct current bus, and the first regulation and control module and the second regulation and control module are of a vertically symmetrical structure; the two regulation and control modules are the same in structure, a primary winding of a three-winding transformer is connected with a medium-voltage alternating-current bus, a wire outlet end of a first secondary winding of the three-winding transformer is connected with a first load through a secondary winding of a first series transformer which is connected in series, and a primary winding of the first series transformer is connected with an alternating-current end of a first three-phase inverter; a wire outlet end of a second secondary winding of the three-winding transformer is connected with an alternating current end of the three-phase rectifier; the medium-voltage alternating-current bus is connected with a second load through a secondary winding of a second series transformer which is connected in series, and a primary winding of the second series transformer is connected with the alternating-current end of the second three-phase inverter. According to the invention, the increasingly complicated power quality requirements under multiple working conditions in the power distribution network facing multi-feeder decoupling regulation and control and mutual assistance are met.

A flyback converter to receive an input voltage and provide an output voltage is provided, and may include a transformer having a primary winding and secondary winding, a primary switch coupled to the primary winding, a synchronous rectifier device coupled to the secondary winding, and a secondary side control circuit to turn on the synchronous rectifier device by outputting a control signal at a first amplitude, subsequently modify the control signal to maintain a voltage across the synchronous rectifier device substantially constant until a predicted time that precedes a current in the synchronous rectifier device reaching substantially zero, subsequently turn off the synchronous rectifier device based on the voltage across the synchronous rectifier device reaching substantially zero, and subsequently turn on the synchronous rectifier device by outputting the control signal at a second amplitude, before the primary switch is turned on. The second amplitude is less than the first amplitude.

A modular and scalable AC / DC substation transforms AC voltage to DC voltage for driving a high-voltage and high-current load, such as a heavy work machine. Sized to fit within a standard high-cube ISO shipping container, the substation includes a main transformer attached at a center of a rectangular base with a pair of controlled rectifiers positioned on the base downstream from the main transformer, aligned parallel to a lateral axis of the base, and substantially symmetrical to a longitudinal axis of the base. The arrangement of these components on the base, together with lowpass filters and switchgear, achieves high power density for the substation, provides balanced mass for stability during shipment and placement, and helps protect personnel from accidental electrical arcing.

The invention discloses a single-phase voltage stabilizing device and a control method and system thereof. Compared with a traditional single-phase full-bridge PWM rectifier and a single-phase full-bridge inverter, the single-phase voltage stabilizing device has the advantages that one bridge arm is reduced, the device cost is lower, fewer devices are needed, fault nodes are correspondingly reduced, and the reliability is higher. The problem of control coupling of a grid-connected input side and an inverter output side is caused due to the fact that one bridge arm is shared, the inverter output side voltage is given to be associated with a grid side, the phases of the inverter output side voltage and the grid side are synchronized, then pulses of the shared bridge arm are naturally decoupled, and the output sinusoidal voltage is obtained. Meanwhile, due to the full-bridge PWM rectification control mode adopted by the grid-connected input side, the grid-side power factor can be 1, and the grid-side current is sinusoidal, so that green grid connection of the device is realized; the inverter output side tracks the network side voltage and introduces the direct current bus voltage as negative feedback, so that the stability of the output voltage is ensured, the stable single-phase voltage output is finally obtained, and the quality of the power supply electric energy in the substation is improved.

The invention provides an overvoltage transient suppression method and system for an automobile generator rectifier and a medium, and relates to the technical field of rectifiers, and the method comprises the steps: carrying out the dynamic continuous data collection of an automobile generator through a transient data collection device, and obtaining an output voltage waveform; a load rejection identification mechanism is introduced to identify and analyze the output voltage waveform, and a real-time load rejection event is obtained; triggering an active protection circuit based on the real-time load throwing event, and generating a real-time protection control decision; and performing transient suppression on the rectifier according to the real-time protection control decision. The technical problems that in the prior art, overvoltage protection of an automobile generator rectifier is slow in response speed and low in protection precision, and the overvoltage transient state cannot be effectively restrained are solved. The technical effects of accurately identifying and responding to the overvoltage event and improving the timeliness and effectiveness of overvoltage transient suppression of the automobile generator rectifier are achieved.

The invention provides a multi-path vibration energy collection device, and the device comprises a mass block which can generate relative movement under the excitation effect; the piezoelectric cantilever beams are arranged on the two transverse sides of the mass block and used for responding to high-frequency micro-amplitude vibration energy; the permanent magnet assembly is fixed in the moving direction of the mass block and is matched with the induction coil to realize magnetoelectric energy conversion; the piezoelectric cantilever beam is connected with the bridge rectifier and the thyristor threshold trigger circuit 1, and the permanent magnet assembly is connected with the bridge rectifier and the thyristor threshold trigger circuit 2 to form a double-independent energy collection channel. The method has the following advantages: (1) a path orthogonal decoupling design is adopted, so that a structure and energy dual-independent acquisition path is realized; (2) the energy conversion efficiency is improved based on a coupling response mechanism of mass block inertia driving; and (3) a thyristor threshold triggering mechanism realizes micro-energy efficient conversion, and the output is stable and reliable.

The invention discloses an on-line monitoring and early warning method for a bus capacitor of an electric driving system, and belongs to the field of electric driving systems. The electric driving system sequentially comprises an isolating circuit, a full-wave bridge rectifier, a bus capacitor bank, an inverter, an actuator and a capacitance online testing device; the capacitor online testing device comprises a relay, a load resistor, a voltage acquisition module, a current acquisition module and a master control calculation unit. When the electric drive system is idle, a load resistor is connected to construct a test path, and current and voltage signals are collected; disconnecting a test path, constructing a degradation characterization quantity of multi-index information fusion through time-frequency domain feature extraction, and constructing an equal-length time interval sequence degradation curve; and the TCN-BRU-GRU combined prediction model carries out trend feature learning and training on the degradation curve. According to the method, waveform fitting and local and global data feature capturing of non-equal-interval time sampling are achieved, trend prediction of bus capacitor performance degradation is achieved, early warning is conducted before failure of the bus capacitor, and safe and reliable operation of an electric drive system is guaranteed.

The embodiment of the invention provides an uninterruptible power supply, a control method of the uninterruptible power supply, related equipment and a system, and relates to the technical field of electric power. Comprising a bypass switch and a DC / AC inverter, and the bypass switch is used for responding to the first control signal to be switched on, so that an alternating current power supply provides active power for a load through the bypass switch; the DC / AC inverter is in an inversion state in response to the second control signal, obtains energy from the DC energy storage equipment, and provides active power of the first set power for the load, so that the active power provided by the AC power supply for the load is smaller than the second set power. According to the uninterruptible power supply provided by the scheme, a rectifier part in a traditional uninterruptible power supply framework is omitted, only the inverter and the static bypass are included, the size of the uninterruptible power supply is reduced, and the equipment cost is reduced. Meanwhile, the direct-current energy storage equipment and the alternating-current power supply simultaneously provide active power for the load after passing through the DC / AC inverter, and peak load shifting of the power of the power grid side is achieved.

The invention relates to the technical field of wireless charging, in particular to a wireless charging system and an application method, and the system comprises m inverters, m-1 RIITs and transmitting coils at a GA end, n first rectifiers at a VA end, RIITs corresponding to n-1 first rectifiers, q second rectifiers, RIITs corresponding to q second rectifiers and receiving coils. The output ends of the n first rectifiers are connected in parallel and are used for outputting electric energy to the high-voltage battery; and the output ends of the q second rectifiers are connected in parallel and are used for outputting electric energy to the low-voltage battery. The high-voltage battery and the low-voltage battery supply energy through the receiving coil at the VA end, the charging mode can be changed by setting the working state of the rectifier, and decoupling control over charging of the high-voltage battery and the low-voltage battery is achieved. According to the invention, the size and cost of the charging structure of the VA end can be effectively reduced, and different levels of power requirements can be met by adjusting the number of inverters and rectifiers.

The invention provides a PWM / Buck cascade circuit auxiliary electrolytic hydrogen production rectification power supply and a control method, and relates to the technical field of electrolytic hydrogen production power supply and intelligent power grids, and the power supply comprises a main power loop and an auxiliary power loop; the main power loop comprises a multi-pulse thyristor rectifier, the power supply side of the multi-pulse thyristor rectifier is connected with an alternating-current power grid, the load side of the multi-pulse thyristor rectifier is connected with one end of a direct-current smoothing reactor, and the other end of the direct-current smoothing reactor is connected with the electrolytic bath; the auxiliary power loop comprises a PWM rectifier and a Buck circuit which are connected in series, the output end of the Buck circuit is connected to the output end of the main power loop in parallel through a direct-current LC filter, the output end of the Buck circuit and the output end of the main power loop are jointly connected into an electrolytic bath for ripple compensation, the multi-pulse rectifier adopts PI control, the PWM rectifier adopts voltage and current double-closed-loop control and SVPWM modulation, Buck adopts PI and feedforward compound control, and the output end of the Buck circuit and the output end of the main power loop are connected in parallel. The system has the advantages of improving the grid-side electric energy quality, the voltage utilization rate, the water electrolysis hydrogen production efficiency and the operation stability.

A variable-frequency drive includes a rectifier, a filter, an inverter, a capacitor bank, and control circuitry. The rectifier converts AC power from a power source to DC power on a DC bus for filtering by the filter. The inverter converts the DC power to three-phase AC power for output to the electric motor. The capacitor bank has one or more capacitors connected to the DC bus. The capacitor bank can store regenerative power on the DC bus from the inverter and can supply the stored DC power to the DC bus for conversion to the three-phase AC power to drive the electric motor. The control circuitry pre-charges the capacitor bank from the AC power of the power source. The control circuitry monitors one or more parameters of the variable-frequency drive and detects one or more fault conditions associated with the one or more monitored parameters.

The invention discloses a flexible interconnection and mode smooth switching method for a distributed power generation system, and relates to the technical field of distributed power generation, and the method comprises the steps: building a droop control relation through continuously collecting DC voltage and current for a source side rectifier of each power generation unit; in a normal mode, the output current of the back-to-back rectifier and the voltage of an intermediate capacitor are collected, the same phase of the current and the load current is kept by using phase locking control, and voltage regulation is realized by combining a dq coordinate model; when a fault of a source side rectifier is detected, an alternating current reference value is generated based on intermediate capacitor voltage deviation and is input into a single current loop controller for voltage stabilization, and meanwhile, a phase advance, adaptive gain and integral saturation resistance mechanism is introduced, so that quick response and stable operation are ensured; in the mode switching process, normal control quantity and fault control quantity are subjected to weighted fusion, and dynamic consistency is achieved through pole matching and reference pre-alignment; the intermediate capacitor voltage fluctuation is significantly reduced, the recovery time is shortened, and the system stability and reliability are improved.

The utility model discloses a field inversion configuration power supply and system of a distributed rectifying device. The field inversion configuration power supply comprises an alternating current source, N resonance branches and an angular pinch coil, each resonance branch is provided with a distributed rectification circuit and a capacitor; the distributed rectifying circuit comprises a plurality of rectifiers which are connected in parallel; one end of the distributed rectifying circuit is connected with an alternating current source, and the other end of the distributed rectifying circuit is electrically connected to the angular pinch coil after being connected with the capacitor; according to the scheme, structural improvement is carried out on the basis of a traditional field inversion power supply technology, and a distributed rectification circuit comprising a plurality of rectifiers connected in parallel is arranged on each resonance branch; by adjusting the working time limit of each independent rectifier in the distributed rectifier circuit, the theta-pinch field inversion device can meet the complex frequency working requirement.

The utility model relates to a device for producing hydrogen by electrolyzing water, in particular to a device for producing hydrogen by electrolyzing water through iron-based circulation assistance. The utility model aims to solve the problems of large electrolytic solution resistance, high equipment complexity and pipeline blockage in the existing water electrolysis technology. The utility model discloses a device for iron-based circulation assisted water electrolysis hydrogen production. The device comprises an electrolyte tank, an ion exchanger, a circulating pump, a transformer, a rectifier, an electrolytic bath, a first compressor, a second compressor, a high-pressure storage tank, a gas storage tank, a plurality of dryers, a cathode, an anode and a proton exchange membrane. According to the utility model, the design of the carbon powder dispensing electrode is adopted to replace the suspension state of coal slurry, and meanwhile, the one-step electrolysis design and the efficient circulation auxiliary module are combined, so that the solution resistance and the equipment complexity are obviously reduced, and the problem of pipeline blockage is solved; the iron-based circulating auxiliary water electrolysis hydrogen production device is efficient, low in power consumption, stable and reliable, and is suitable for large-scale industrial popularization.

Examples described herein provide a circuit that includes a power electronics converter disposed in a vehicle, the power electronics converter to receive alternating current (AC) electrical power from an AC grid source and to provide AC electrical power to an AC load external to the vehicle. The power electronics converter includes an AC-AC converter that includes a rectifier and an inverter, the rectifier being electrically connected to the inverter by a direct current (DC) link. The circuit further includes an on-board charging module electrically connected to the power electronics converter and a battery disposed in the vehicle. The power electronics converter provides vehicle-to-load functionality by providing, to the AC load, AC electric power as an output of at least one of a 120 Vac output or a 240 Vac output.

The invention relates to the technical field of UPS intelligent diagnosis, in particular to a UPS self-diagnosis system based on artificial intelligence, which is characterized in that a storage battery assembly can be charged through a rectifier to store electric energy, and a monitoring module monitors the output voltage condition of the storage battery assembly and the temperature and humidity change condition of a storage battery pack area; historical data monitored by a monitor are stored through an AI analysis module, influence periods are divided and operation conditions are monitored through a control module based on power supply influence tendency characterization values corresponding to different battery management influence periods, and power supply output characterization parameters are determined to predict whether the power supply effect of a storage battery pack meets a preset standard or not. Whether the electric energy compensation device is started or not is determined, the influence of temperature and humidity resistance differences of all single batteries of the storage battery pack on the power supply efficiency in the operation process of the UPS self-diagnosis system is considered, the electric energy compensation device is adaptively involved, and then the power supply efficiency and the battery stability of the UPS self-diagnosis system are guaranteed.

The invention provides a permanent magnet synchronous motor frequency conversion soft start and grid connection device and a control method. The device comprises a power supply grid (1), a permanent magnet synchronous motor (2), three-phase contactors (3), (4) and (5), a variable frequency controller composed of a rectifier (6), an inverter (7) and a control panel (8), a voltage sampling module (9), a current sampling module (10) and a filter inductor (11) at the output end of the inverter. One end of the three-phase contactor (3) is connected with a three-phase inlet wire of the power supply grid (1), and the other end of the three-phase contactor (3) is connected with the input end of the rectifier (6); one end of the three-phase contactor (4) is connected with the output end of the inverter (7), and the other end of the three-phase contactor (4) is connected with the input end of the motor (2); and one end of the three-phase contactor (5) is connected with a three-phase inlet wire of the power supply grid (1). VF open-loop pre-synchronization control is introduced in advance in vector control, power grid synchronization conditions are simulated, a motor is enabled to actively match power grid magnetic field parameters before grid connection, smooth transition of a control mode is realized, and large impact current and electromechanical oscillation are avoided.