128 results about "Space vector modulation" patented technology

The invention is suitable for the technical field of flexible power distribution of a power system, and discloses a modular multilevel converter multi-objective optimization method, system and device based on model predictive control and space vector modulation, and a medium. Obtaining an output current reference value and a circulating current reference value; obtaining a reference voltage vector based on the output voltage reference value, and screening out a plurality of groups of redundant voltage vector sequences through a space vector diagram; performing performance evaluation through rolling optimization by combining each redundant voltage vector sequence with a multi-target cost function to obtain an optimal voltage vector sequence; and on the basis of the optimal voltage vector sequence and the corresponding duty ratio, a switching signal for driving each sub-module switching device of the MMC is generated, and multi-target cooperative control is realized. The three targets of reference output current tracking, circulating current suppression and sub-module capacitor voltage balance are met, and the dynamic response capability, efficiency and reliability of MMC system operation are comprehensively improved.

The invention discloses a flux linkage tracking full-speed-domain high-precision predictive current control method for a permanent magnet synchronous motor, and the method comprises the steps: sampling a phase current signal, a position signal and a speed signal of the permanent magnet synchronous motor, and obtaining a dq sampling current through coordinate transformation; calculating a predicted current according to the established tracking discrete model; the sinusoidal variation characteristic and the dynamic transient characteristic of the resistance voltage drop are accurately considered in the current prediction and reference voltage calculation stage, and the resistance voltage drop is accurately represented through accurate feed-forward compensation of predicted current and reference voltage; a driving signal of the inverter is obtained through coordinate transformation and space vector modulation, and full-speed-domain high-precision fast-response current prediction control over the permanent magnet motor is achieved. According to the method, the current flow steady state control error caused by the model error is reduced, the current control precision and the dynamic response performance of the permanent magnet synchronous motor in the full-speed domain are effectively improved, and a high-precision model basis is provided for high-precision position-free control and parameter online identification.

The invention relates to the technical field of motor control, and particularly provides a control method and system suitable for a one-way running motor of a two-wheeled electric vehicle. The method aims to solve the problems of unstable motor operation and insufficient reliability caused by torque pulsation in the prior art. The method comprises the following steps: executing off-line identification of motor parameters to obtain initialized parameters; multi-source operation state signals are collected, and a vehicle working condition judgment result is obtained through fusion analysis; performing fault diagnosis and grading evaluation to form a fault-tolerant instruction; dynamic dead zone compensation and self-adaptive overmodulation are implemented by combining the parameters and the working conditions, and an optimization control instruction is output; generating a PWM driving signal through space vector modulation; and responding to the fault-tolerant instruction, and fusing a sensorless algorithm and a health sensor signal to realize degraded operation. According to the invention, the smoothness and efficiency of motor operation and the fault-tolerant capability of the system are effectively improved.

The invention relates to a method for improving the grid-connected stability of a grid-forming type inverter based on inductive current feedforward and coupling enhancement, and belongs to the technical field of inverter control. The method comprises the following steps: measuring inverter port voltage and filter inductive current, and calculating output active power and reactive power; calculating a port voltage reference value according to the amplitude and phase angle reference of the port voltage generated by the active controller and the reactive controller respectively; and taking the port voltage as a feedback value of the voltage regulator, and subtracting the feedback value from the port voltage reference value to serve as the input of the voltage regulator. And then adding the feedforward inductive current to the output of the voltage regulator to obtain a current reference value, and subtracting the inductive current from the current reference value to serve as the input of the current regulator. And finally, the output of the current regulator is added with the feedforward port voltage and combined with the cross-coupling enhanced voltage to obtain a modulation signal, and the modulation signal is subjected to space vector modulation to generate a driving signal so as to control the inverter. According to the method, on the premise that hardware cost and software complexity are not increased, the stable operation capacity of the grid-forming inverter under the strong power grid working condition is improved.

The invention relates to the technical field of voice recognition and intelligent household electrical appliance control, in particular to an induction cooker control method based on voice recognition, which comprises the following steps: synchronously acquiring a voice signal and a lip motion signal, and generating multi-modal sensing data through timestamp alignment; performing cross-modal anti-noise processing on the data, and outputting a fusion feature tensor fusing acoustic and visual features; semantic analysis and danger instruction recognition are executed, and a risk filtering control instruction containing temperature / fire parameters is generated; calling a thermodynamic dynamic model to calculate a power control parameter based on the instruction parameter; converting a power parameter into a space vector modulation waveform to drive a load circuit, and synchronously collecting the pot bottom temperature; and triggering an anti-noise process and thermodynamic model parameter updating according to the deviation between the actual temperature and the target temperature. Noise interference is reduced through multi-modal signal cross validation, dangerous instructions are intercepted in combination with knowledge graph constraints, the noise suppression capability and the temperature control precision are continuously optimized, and the safety and reliability of voice control in a complex environment are improved.

The invention discloses an LC filtering type permanent magnet motor system prediction flux linkage control method and system and a medium, and belongs to the field of power electronics and power transmission. State variables of an LC filtering type permanent magnet motor system at the k moment are sampled, a discrete state-space equation of the system is established by adopting a zero-order retainer method, and a stator flux linkage vector prediction model is established; obtaining a stator flux linkage vector reference by using the electromagnetic torque reference and the parameters of the permanent magnet motor; constructing a loss function, and solving an inverter optimal control vector reference considering the system voltage constraint; park inverse transformation is referred to for the optimal control vector of the inverter, control pulses are generated through space vector modulation and act on an inverter switching tube, and LC filtering type permanent magnet motor system predictive flux linkage control is completed. According to the method, common control of the torque and the flux linkage can be realized only by controlling the stator flux linkage vector, and excellent torque flux linkage control performance can be obtained without any design parameter.

The invention provides a permanent magnet motor continuous set model-free predictive control method based on Bayesian optimization, and relates to the field of permanent magnet synchronous motor control. The method comprises the following steps: acquiring a hyper-local model and an extended state observer; determining the bandwidth and the input gain as optimization variables, and obtaining a training set and a test set for Bayesian optimization; joint probability distribution of the training set and the test set is calculated through a kernel function, and a prediction mean value and a prediction variance of optimization variables are determined; an optimization variable combination is screened based on the expected value collection function, and the bandwidth and the input gain are updated based on the optimization variable combination; based on the updated extended state observer and the hyper-local model, calculating the reference voltage of the next control period by using a dead-beat control principle; the reference voltage is decomposed into basic voltage vectors through space vector modulation, and the switching sequence of the basic voltage vectors is executed according to the minimum switching times to drive the permanent magnet motor. The method is not affected by motor parameter changes, and the current prediction control steady-state performance can be improved.

The invention discloses a single-stage interconnection converter port power distribution method based on a multilayer space vector modulation strategy. The method comprises the following steps: firstly, obtaining a single-stage interconnection converter alternating current side reference voltage vector through an energy management strategy, a power control loop and a current and voltage double closed loop of a hybrid alternating current and direct current micro-grid; then, the single-stage interconnection converter is subjected to equivalent decoupling modeling to form four virtual two-level converters, a four-layer space vector diagram is obtained, scaling factors for decomposing reference voltage vectors are calculated according to given reference power, and therefore the two reference voltage vectors on the alternating current side are decomposed into four independent voltage vectors; and synthesizing the four voltage vectors in a four-layer space vector diagram to obtain the duty ratio of each phase of the four two-level converters so as to obtain the switching sequence of the single-stage interconnection converter.

The invention relates to the technical field of generator control, and discloses an intelligent vehicle-mounted high-power self-generating control method and system. The method comprises the following steps: acquiring operating parameters of a generator set, performing high-precision digital processing, realizing constant-rotating-speed control through cooperation of multiple controllers based on a rotating-speed fluctuation characteristic value, performing power factor correction through coordinate transformation and active rectification to obtain a direct-current bus voltage, performing precise voltage stabilization by adopting a multi-phase interleaving converter, and outputting the direct-current bus voltage. And finally, outputting a high-quality three-phase alternating-current power supply through space vector modulation and closed-loop feedback control. The technical problems in the prior art that the power supply quality control capability is insufficient, the intelligent level is low, the environmental adaptability is poor, the load adaptability is limited, and the maneuverability is limited are solved.

The invention provides an SVG current adjustment method and system of a photovoltaic power station, and belongs to the technical field of SVG current adjustment. The method comprises the following steps: acquiring a current signal and a voltage signal based on a transformer deployed by SVG; calculating the current deviation, and analyzing the voltage fluctuation condition based on the collected voltage signal to predict the operation state of the power grid; selecting an SVG current adjustment strategy according to the calculated current deviation and the predicted power grid operation state; generating a corresponding adjustment instruction by using the selected SVG current adjustment strategy; and according to the adjustment instruction, controlling the switching action of a power device of the SVG so as to adjust the output current of the SVG. According to the invention, through various SVG current adjustment strategies, the method can adapt to working conditions and current deviation so as to ensure the stability and accuracy of SVG output current; through feedforward decoupling control and a space vector modulation technology, rapid and stable execution of an instruction is ensured, power consumption is reduced, and service life attenuation of equipment is inhibited.

The invention belongs to the technical field of motor driving control, and discloses a space vector modulation strategy method for a permanent magnet synchronous motor, which comprises the following steps of: searching a region division and vector arrangement table by using regions in which Vlp and V are positioned to obtain an optimal vector sequence, and arranging vectors based on a principle of eliminating a peak of a CMV and minimizing switching operation times; and finally, calculating the duty ratio of a plurality of effective voltage vectors used for synthesizing the next period according to the amplitude-second balance principle. Compared with a control strategy that only one effective vector or two adjacent effective vectors are used in each control period, the virtual vector synthesized by the method is the same as the reference vector, and common-mode voltage spikes can be eliminated by the method; compared with NSPWM and AZPWM, the method has the advantages that area division and vector sorting are reasonably arranged, so that the switching action times are minimized, the switching loss is reduced, and the inverter efficiency is improved.

A multi-source inverter (MSI) topology features significant advantages over conventional MSI converters such as NPC-based and T-Type-based topologies, including a lower number of switching devices, higher efficiency, and better thermal distribution of switching devices. A space vector modulation (SVM) scheme for MSI topologies presented herein and for conventional MSI topologies uses three or four adjacent vectors to generate a reference voltage vector, resulting in lower voltage and current total harmonic distortion (THD) at the MSI output, a lower switching frequency, and increased efficiency relative to conventional MSI modulation. Embodiments are suitable for use in electric vehicles and energy storage systems.

The invention provides a vehicle differential steering control method based on motor modulation, terminal equipment and a storage medium. The problems that in the prior art, the response speed is low, the control precision is low, and complex road condition changes are difficult to adapt are solved. Comprising the following steps: periodically acquiring real-time rotating speed signals of left and right wheel motors, and averaging the real-time rotating speed signals through a moving average filtering algorithm; and comparing the average rotating speed data of the left and right wheels, and judging whether the vehicle tends to turn leftwards or rightwards or not. Calculating the expected steering radius and the current linear speed according to a differential control algorithm, determining the due rotating speed difference of left and right wheels, and adjusting the rotating speed of the motor. Factors such as an Ackerman steering geometric model, a road adhesion coefficient and a side slip angle are introduced, and calculation of the steering radius is optimized. A three-phase driving signal is generated through space vector modulation, the on-off state of a three-phase inverter is controlled, and accurate speed control is achieved.

The invention discloses a three-phase three-wire three-level hybrid modulation switching method and device and a medium, and the method comprises the following steps: obtaining a three-phase sinusoidal modulation wave, and superposing a primary common-mode voltage to obtain a continuous first modulation wave; if the continuous space vector control is executed, comparing the first modulated wave with a carrier wave to form a first duty ratio signal; if the intermittent space vector control is executed, superposing the first modulation wave and a secondary common mode voltage based on a unified coefficient to obtain an intermittent second modulation wave; and according to a specific mode of intermittent space vector modulation, assigning a value to the unified coefficient to obtain a corresponding target intermittent space vector modulation wave. The device and the medium are both used for implementing the method. The method has the beneficial effects that the degree of freedom of the algorithm can be maximized through a PWM unification and coefficient modulation strategy; compared with a traditional mode, the complexity of an algorithm can be effectively reduced, and the reliability of overall code execution can be improved.

The invention discloses a current-limiting control method based on a network-forming static var generator. The current-limiting control method comprises the following steps: inputting an external direct-current voltage, stabilizing the voltage by a capacitor, and then outputting the voltage to an inverter bridge; the inverter bridge generates controllable alternating current through space vector modulation; the inductive filter filters high-frequency harmonic output end voltage; the terminal voltage amplitude and phase are monitored in real time, and current-limiting control is triggered based on the phase deviation between the voltage and the virtual internal potential when the voltage of the power grid drops; the terminal voltage interacts with ideal power grid voltage at a common coupling point through power grid impedance to generate PCC voltage; pCC voltage and output current are detected, and instantaneous power is calculated; the power signal is filtered and de-noised and then a modulation instruction is generated by the current-limiting controller and is fed back to the inverter bridge to form a closed loop. The reactive power supporting voltage is injected preferentially, the voltage drop amplitude is remarkably reduced, the inertia damping supporting capacity of the system is enhanced, power grid fault recovery is accelerated, and meanwhile the voltage instability problem caused by a traditional current limiting strategy is avoided.

The invention relates to a space vector modulation method based on a single-phase parallel current source inverter, and the method comprises the following steps: 1, constructing a single-phase parallel current source inverter circuit, and dividing all current vectors of the single-phase parallel current source inverter according to different amplitudes of output current Iw; 2, analyzing the influence of the small-current vector redundant switching state on the direct current, and constructing a small-current vector switching state selection strategy; 3, analyzing the influence of the zero-current vector redundant switching state on the direct current, and constructing a zero-current vector switching state selection strategy; and step 4, in each sampling period, synthesizing a reference current vector Iref by two static current vectors which are closest to each other according to an ampere-second balance principle, collecting a power grid voltage us and direct currents i1-i4 at the same time, and selecting a redundant switch state according to the strategies in the step 2 and the step 3 to realize the current balance of the direct current bridge arm. According to the invention, the waveform quality of the grid-connected current can be improved.

This invention relates to the field of inverter technology, and particularly to a heterogeneous power device hybrid inverter and its space vector modulation method. The heterogeneous power device hybrid inverter provided in this invention includes a first constant current source, a second constant current source, a main power inverter module, a secondary power inverter module, and a capacitive reactance module. The first constant current source is connected to the main power inverter module to provide current to the main power inverter module. The main power inverter module includes multiple silicon-based insulated-gate bipolar transistors (SBMTs) as main switching transistors, and the main power inverter module is connected to the capacitive reactance module. The second constant current source is connected to the secondary power inverter module to provide current to the secondary power inverter module. The secondary power inverter module includes multiple silicon carbide-based metal-oxide-semiconductor field-effect transistors (MOSFETs) as secondary switching transistors, and the secondary power inverter module is connected to the capacitive reactance module. The heterogeneous power device hybrid inverter and its space vector modulation method provided by this invention can balance high inverter frequency and low switching losses.

The invention provides a double-fed gravity energy storage system synchronous phase locking control method and device under unbalanced power grid voltage, and the method comprises the steps: obtaining related parameters of a double-fed motor, carrying out the band-pass filtering, Clarke transformation and dynamic filtering, generating a positive sequence component, generating a synchronous rotation angle through a phase-locked loop, and carrying out the dynamic filtering of the positive sequence component, thereby achieving the synchronous phase locking control of the double-fed gravity energy storage system. A rotor excitation voltage is generated through coordinate transformation, PI control and a composite regulator, and a switching signal is generated through space vector modulation after superposition excitation compensation, so that the rotating speed and reactive power stable control of the double-fed motor is realized, and the stable operation of the system when the power grid voltage is unbalanced is guaranteed.

The invention relates to a space vector modulation method and device of a three-level inverter and a storage medium, and belongs to the technical field of converter control. Determining a fundamental voltage vector for synthesizing the reference voltage vector and an action time of the fundamental voltage vector; based on the action time of the basic voltage vector, determining the action sequence and time distribution of the basic voltage vector; adjusting the action time of a redundant small vector in the basic voltage vector based on the bus midpoint potential balance control fine adjustment amount, and obtaining the action sequence and time distribution of the adjusted basic voltage vector; and comparing the generated three-phase modulation wave with a triangular carrier wave, and outputting a PWM pulse to drive a three-level inverter to generate a corresponding switching state based on a comparison result. According to the method provided by the invention, the conduction time of the power device can be prolonged, and the minimum pulse width conduction time of the power device is avoided.

The invention belongs to the field of regulation and control of standby power supply loop devices, and provides a low-cost converter regulation and control method and system for a standby power supply system, and the method comprises the steps: sampling load voltage and current, inductive current, and DC side upper and lower capacitor voltage; selecting inductive current to perform decoupling operation, calculating expected output voltage of the converter based on a dead-beat control principle, and performing normalization processing; determining a sector with an optimal size according to an amplitude condition and a boundary condition of the expected output voltage; based on discrete space vector modulation, selecting a low common-mode voltage vector to synthesize a virtual small vector and a virtual medium vector, and expanding a candidate vector set; determining a switching sequence at the next moment according to the large and small sectors where the expected output voltage is located and the voltage difference value of the upper and lower capacitors on the direct current side to balance the neutral point voltage and the fixed switching frequency; and calculating the action time of the voltage vector according to the value function, outputting the duty ratio of the voltage vector, and applying the duty ratio to a switching device of the converter.

The application discloses a permanent magnet synchronous motor model prediction torque control method based on a hybrid mode optimization. The method first constructs a reference voltage vector through a torque error target function and a discretization prediction model of the permanent magnet synchronous motor, and then designs a hybrid mode optimization algorithm. The algorithm first designs a double-vector mode optimization on the sector boundary of a voltage space vector diagram, and then designs a three-vector optimization mode based on a discrete space vector modulation inside the sector. The optimal synthesized voltage vector obtained by the hybrid mode optimization algorithm is transmitted to a voltage error target function to realize the switching of the two modes, so that the control execution mode and the optimal synthesized voltage vector are determined. The control method disclosed by the application has high freedom to adjust the amplitude and position of the synthesized voltage vector, and thus has high steady-state performance of the control system and fast torque dynamic response in the full speed range.

The invention provides a down-sampling repetitive controller applied to a three-phase four-leg inverter, and the controller comprises an ADC sampling unit which is used for sampling an output phase voltage and an inductive current of the three-phase four-leg inverter at a switching frequency F (S), and converting the output phase voltage and the inductive current into an alpha beta 0 reference system through Clark transformation; the repetitive control unit is used for subtracting the output phase voltage and the inductive current after the Clark transformation from a reference voltage and a reference current to obtain an error voltage signal and an error current signal, applying the error voltage signal and the error current signal to an RC (Resistance-Capacitance) circuit, and performing down-sampling according to a preset proportion; and performing state feedback control on the output of the RC circuit so as to generate a three-dimensional space vector modulation component to act on the three-phase four-leg inverter. The method has the advantages that (1) a closed-loop system pole is arranged by using a state feedback strategy to stabilize the system, so that LPF does not need to be introduced; and (2) designing an integer phase lead compensator.

The invention relates to a model prediction control method and device for dynamically adjusting a prediction range. The method comprises the following steps: performing one-beat delay compensation on a motor system according to sampled data, and adjusting a prediction range of the one-beat delay compensation according to an actual switching frequency of the motor system at the current moment and a preset target switching frequency; calculating a reference voltage vector of the motor system based on a current dead-beat control principle, and performing space vector modulation on the reference voltage vector based on a volt-second balance principle to obtain a plurality of candidate voltage vector sequences; and selecting the candidate voltage vector sequence with the minimum harmonic current effective value as an optimal voltage vector sequence, and controlling the action of the motor system at the future moment according to the optimal voltage vector sequence. According to the method provided by the invention, the current harmonic is relatively small by adjusting the prediction range, limiting the switching frequency and screening the voltage vector sequence, so that the steady-state performance of the motor system is improved.

The present application discloses a pulse modulation method, apparatus, and computing device based on a nine-segment three-level converter. The method includes: normalizing the vector space to generate a normalized sector; converting the target vector into a vector within the normalized sector, recorded as a normalized vector; selecting a reference vector with the same angle as the normalized vector, and calculating the action time of the basic vector synthesizing the reference vector to obtain the switching timing of the reference vector; superimposing a preset PWM wave on the switching timing of the reference vector to generate an equivalent switching timing of the normalized vector; and obtaining a nine-segment switching state timing diagram of the target vector based on the corresponding relationship between the target vector and the first vector. This method greatly reduces the computational complexity of the three-level converter space vector modulation algorithm and ensures that the system harmonic distortion (THD) is within an acceptable range.

This invention proposes an innovative model predictive control-based current control method and system for permanent magnet synchronous motors (PMSMs), aiming to address the problems of slow dynamic response and low control accuracy in traditional control methods when facing parameter variations and external disturbances. By constructing an accurate mathematical model, this invention not only improves the dynamic response speed and control accuracy of the motor but also significantly reduces torque ripple, thereby enhancing the stability and reliability of motor operation. Furthermore, the introduction of intelligent algorithms such as neural networks or fuzzy logic, as well as adaptive control algorithms, further enhances the system's adaptability and robustness. The application of space vector modulation technology optimizes the current waveform, further reducing torque ripple and improving the smoothness of motor operation. The control method of this invention is suitable for industrial applications with extremely high requirements for dynamic performance and control accuracy, demonstrating its broad application potential in the field of modern industrial motor control.

A method (100) for operating an inverter (1) wherein the inverter selectively connects three AC phases (U, V, W) of an inductive load (4) to the positive or negative terminal of a DC voltage (2) provided at the input terminal (1a) of the inverter (1) by manipulating switching elements (3a-3f) arranged in three half-bridges (5a-5c), wherein the switching state (110) of the switching elements (3a-3f) is changed by rotating space vector modulation, wherein, additionally, when the space vectors (6a-6f) having the same switching state of the corresponding switching elements (3a, 3d; 3b, 3e; 3c, 3f) of at least one half-bridge (5a-5c) are modulated, such half-bridges (5a-5c) remain completely off (120).

The present invention discloses a three-level three-phase four-wire four-leg inverter three-dimensional space vector modulation method and system. The method includes: analyzing and determining an equivalent switching model of the topology of the three-level three-phase four-wire four-leg inverter, and mapping the three-phase voltage corresponding vectors of the three-level three-phase four-wire four-leg inverter to the α-β-γ three-dimensional coordinate system; according to the distribution characteristics of all switching three-dimensional space vectors in the α-β-γ coordinate system, rotating or symmetrically mapping the vectors in each main region to the three-dimensional space corresponding to the first major sector on the plane; determining the vector synthesis method for each tetrahedral block, and for irregular tetrahedrons that do not conform to the vector sequence generation principle, using the vector replacement and virtual vector synthesis methods; according to the vector synthesis method, giving the block division method for the three-dimensional space corresponding to the first major sector, and the corresponding duty cycle calculation method. The present invention analyzes the equivalent switching model of the topology structure, and maps it to the three-dimensional space through α-β-γ coordinate transformation to determine the vector synthesis method for any tetrahedral block.

A power converter and a circuit arrangement. The power converter has a series circuit, including first and second intermediate circuit capacitors, connected in parallel to first and second half-bridges. A first terminal of a first center switch is connected to a center point of the first half-bridge and is configured to provide a first phase. A first terminal of a second center switch is connected to a center point of the second half-bridge of the power converter and is configured to provide a second phase. A second terminal of the first center switch and of the second center switch are connected and configured to provide a third phase. An evaluation unit is configured to actuate the first and second half-bridges, the first center switch, and the second center switch based on a space vector modulation and to adjust a voltage ratio between the first and second intermediate circuit capacitors.

The invention provides a fault-tolerant control method for an open-circuit fault of a single switch tube of a five-phase permanent magnet synchronous motor. The method comprises the following steps: deducing each phase voltage according to a fault position and reconstructing a space voltage vector; then a virtual voltage vector is generated by applying a discrete space vector modulation technology so as to expand a candidate vector set, and optimization is carried out through sector division; a third harmonic current is reduced by setting a specific segmented given current; and finally, by constructing a voltage error value function, a current prediction step in traditional model prediction is omitted, and an optimal voltage vector is directly selected to generate a PWM signal. According to the method, the torque ripple and the current harmonic can be effectively suppressed without modifying a motor mathematical model and a reduced-order transformation matrix, and the method has high dynamic performance and good universality.

The invention discloses a state-of-charge balance control method and device and a medium, and the method comprises the steps: carrying out the calculation of the target three-phase adjustment power through the working voltage and working current of each phase in a direct-hanging type energy storage system, and the current charging and discharging power, carrying out the fundamental wave zero-sequence voltage conversion based on the target three-phase adjustment power, and carrying out the balance control of the state-of-charge. And the target zero-sequence voltage is injected into the three-phase modulation voltage after space vector modulation, so that real-time balance control over the three-phase charge state under the unbalanced working condition of the power grid is achieved, the control effect is improved, the zero-sequence voltage injection range is increased, and the control precision is improved. And the control speed for realizing the equilibrium state is improved.