128 results about "Three level inverter" patented technology

The invention relates to the field of three-level inverters, and particularly discloses a model-free strong-robustness predictive control method and system for a three-level SNPC inverter, and the method comprises the steps: carrying out the real-time sampling and coordinate transformation of the inverter, and obtaining the current and voltage components under a two-phase static coordinate system; establishing a hyper-local model, enabling the system parameter deviation and the external disturbance to be uniformly equivalent to lumped disturbance, and designing a full-order sliding-mode observer for real-time estimation; calculating a reference voltage vector based on the disturbance estimation value and the extrapolated reference current; and an optimal double-vector combination is selected through space vector optimization, action time is solved, redundant small vectors are selected according to midpoint voltage deviation, and PWM driving signals are generated. According to the method, excellent current tracking performance and low harmonic distortion can still be kept under the conditions of parameter mismatch and working condition change, meanwhile, neutral-point potential balance on the direct-current side is achieved, and the method has the advantages of being small in calculation amount, high in robustness, easy to achieve in engineering and the like.

The invention discloses a multi-loop anti-interference ride-through control system and method for a high-voltage three-level inverter, and is suitable for a three-phase T-type three-level grid-connected inverter. The system comprises a direct current side power supply circuit, an inversion main circuit, a filtering grid-connected circuit, a signal sampling and conditioning circuit, a multi-loop cooperative controller and a PWM driving and protecting circuit. According to the control method, a robust synchronous reference is provided through an outer ring virtual synchronous generator strategy; a middle ring adopts a virtual impedance model containing a high-frequency compensation item to selectively suppress switching noise; the inner ring adopts a quasi-proportional resonance controller to realize fundamental current zero-static-error tracking; the modulation layer dynamically optimizes a discontinuous pulse width modulation strategy based on a real-time EMI index; and the rings are switched to a low-voltage ride-through mode in cooperation when a fault occurs. On the premise of not increasing hardware, the anti-interference capability, the current quality and the ride-through stability of the inverter under the working conditions of strong electromagnetic interference and power grid drop are effectively improved.

The invention belongs to the technical field of electronic power, and particularly relates to a multi-target hybrid modulation method, system and equipment for a T-type three-level inverter, and the method comprises the steps: firstly, judging whether the inverter operates at an extremely low modulation degree or not; if yes, calculating theoretical midpoint current of the DPWM1 mode and the DPWM3 mode in parallel, and expanding midpoint current corresponding to four hybrid modulation modes generated after a VSVPWM sequence is introduced in the two modes respectively; then dynamically selecting an optimal hybrid modulation mode or returning to a basic DPWM mode according to the numerical relationship between the real-time calculated midpoint compensation current and each midpoint current; and finally, a three-phase double-modulation wave is generated, and PWM signals for driving all power switches are output after carrier wave comparison. According to the method, multi-objective optimization of the neutral point potential, the switching loss and the output waveform under the extreme working condition is realized, and the stability and the performance of the system are remarkably improved.

The invention provides a common-mode voltage suppression method for a three-level four-leg inverter, and relates to the technical field of power electronics. Aiming at the problem that the common-mode voltage is relatively high in the application of the existing three-level four-bridge-arm inverter, the invention proposes that two bridge arms in four bridge arms of the inverter are subjected to anti-sequence operation, so that the common-mode voltage is effectively inhibited; the method comprises the following steps: calculating terminal voltages of four bridge arms, selecting a bridge arm for performing desequencing operation based on a desequencing operation bridge arm pairing rule, and adjusting a modulation waveform of each bridge arm; compared with a traditional three-level inverter modulation method, simulation comparison analysis shows that the common-mode voltage is remarkably reduced; the common-mode voltage performance comprehensive comparison of the six anti-sequence modes shows that the anti-sequence operation used in the method has the optimal performance.

The invention relates to the technical field of energy storage converters, in particular to a three-level inverter DPWM and SVPWM smooth switching method and system, a medium and equipment, and the method comprises the steps: determining a current modulation mode which comprises the SVPWM and the DPWM; a first modulation coefficient and a second modulation coefficient are set, the first modulation coefficient corresponds to the weight of the SVPWM common-mode voltage, the second modulation coefficient corresponds to the weight of the DPWM common-mode voltage, and the sum of the first modulation coefficient and the second modulation coefficient is constantly 1; determining values of a first modulation coefficient and a second modulation coefficient based on the current modulation mode in response to a switching instruction of switching from the current modulation mode to a target modulation mode; and combining the three-phase SPWM modulation wave, the first modulation coefficient, the SVPWM common-mode voltage, the second modulation coefficient and the DPWM common-mode voltage to generate a total modulation wave. According to the invention, non-stop switching of SVPWM and DPWM is realized, fast and stable neutral-point voltage and smooth transition of neutral-line current and three-phase current are ensured when two modulation modes are switched, and the smooth transition requirement of mode switching is met.

The invention discloses an inverter IGBT intelligent fault diagnosis method based on a multi-scale attention network, and relates to the technical field of power electronic equipment fault diagnosis. A three-phase current signal of a three-level NPC inverter is collected and preprocessed; multi-dimension fault features of the current signals are extracted in parallel through multi-scale depth separable convolution; a scale-aware efficient attention mechanism is introduced to carry out weighted optimization on each scale feature, and key fault information is strengthened; and outputting a fault diagnosis result through a feature fusion and classification network, and performing INT8 quantization processing on the model to adapt to an embedded deployment scene. The method has the advantages of being high in multi-scale feature capturing capacity, high in diagnosis precision and light in model weight, and can meet the dual requirements of industrial application for real-time performance and accuracy.

The invention discloses a three-level inverter open-circuit fault diagnosis method based on fault feature vector prediction, and the method comprises the steps: reconstructing a theoretical stator current through reference current based on a motor steady-state model, and introducing an amplitude per-unit algorithm to calculate a current residual error, thereby recognizing the fault, and locking a fault phase; collecting a system state at the moment of fault triggering, deducing a modulation switch sequence in a future detection period on line by using a reference voltage vector time sequence prediction model, and generating a dynamic reference value of theoretical action times of each switch state; performing real-time statistics on the actually-measured cutoff times of the fault phase in different switch states by using an edge triggering mechanism, and constructing an actually-measured feature vector; and determining a fault device by calculating the minimum distance between the actual measurement vector and each fault modal theoretical feature. The method can effectively eliminate the influence of the rotating speed and load change of the motor on the diagnosis threshold, solves the problem that the fault features of the inner tube and the clamping diode are overlapped and are difficult to distinguish, and improves the robustness and accuracy of fault diagnosis.

The present application relates to a kind of full digital hysteresis control method of inductance-free three-level inverter sampling time online prediction, belong to power electronic converter technical field, solve the dependence of full digital hysteresis control algorithm of three-level converter on high sampling rate, and the problem of being greatly influenced by main circuit filter parameter, it includes determining the mathematical model and modulation method of three-level converter, determining the full digital three-level hysteresis control algorithm of inductance-free sampling time online prediction, correction prediction sampling time interval.The full digital hysteresis control method is used for inductance-free three-level inverter hysteresis control simulation.

The application provides a three-level inverter fault diagnosis method based on an output voltage vector image, and relates to the technical field of power electronic equipment state monitoring and fault diagnosis, and the method comprises the following steps: collecting three-phase output voltage signals in real time by an inverter master control microcontroller, obtaining voltage vector sequences in a two-phase stationary coordinate system after filtering, normalization and Clarke transformation; setting a short-time analysis window, generating a two-dimensional gray image representing the instantaneous motion trajectory form of the voltage vector by coordinate mapping, bilinear interpolation and gray processing on the continuous vector sequences in the window; loading and executing a pre-quantized lightweight convolutional neural network model by using a special lightweight convolutional neural network model integrated in the microcontroller, performing real-time inference and fault mode matching on the trajectory image; and feeding back the microsecond-level diagnosis result to the main processor core by the model through a hardware interrupt, so as to trigger immediate protection or fault-tolerant control.

The invention relates to a method for heating a high-voltage battery (2) of a high-voltage system (1) of an electrically powered vehicle, wherein the high-voltage system (1) comprises an inverter (4) and at least one capacitor (C_X1, C_X2) in an intermediate circuit, wherein the inverter (4) has two high-voltage potentials (P+, P-) as DC voltage terminals and three phase terminals to which an electric machine (3) is connected, wherein the inverter (4) has a plurality of semiconductor switches (S1 to S12), wherein energy is transferred between the high-voltage battery (2) and the at least one capacitor (C_X1, C_X2) using the semiconductor switches (S1 to S12), the at least one capacitor (C_X1, C_X2) and the motor inductances (L1, L2, L3) of the electric machine (3), wherein the inverter (4) is designed as a 3-level inverter, and wherein the intermediate circuit is a series connection of two Capacitors (C_X1,C_X2) with a center tap (M) connected to the inverter (4), wherein energy is alternately transferred between the two capacitors (C_X1, C_X2) using the semiconductor switches (S1 to S12) of the inverter (4) in order to cause a correspondingly reversing current flow between the high-voltage battery (2) and the capacitors (C_X1, C_X2) and thus to heat the high-voltage battery (2).

This application relates to the field of power electronics technology and discloses a method, device, equipment, and storage medium for detecting the aging of DC capacitors in a three-level inverter. The method includes: obtaining a simplified topology model of the three-level inverter; based on the working principle of the three-level inverter, controlling the midpoint current to zero by injecting a zero-sequence voltage into the three-phase reference voltage; under the state of midpoint potential balance, monitoring a first current and a second current using the correlation between capacitor current and capacitance value, calculating the current ratio of the first current and the second current, and deriving the capacitance ratio of the first capacitor and the second capacitor based on the current ratio; and identifying the aging state of the capacitor online based on the capacitance ratio. The device, equipment, and storage medium all correspond to this method. This application achieves online aging identification of capacitors by monitoring the current changes of the upper and lower DC capacitors of a three-level inverter, under the premise that the midpoint potential balance of the three-level inverter is controlled.

The application discloses a three-level inverter harmonic suppression method based on zero vector symmetrical reconstruction and spread spectrum composite modulation, and the method comprises the following steps: step 1, signal acquisition and voltage instruction acquisition; step 2, spread spectrum modulation parameter setting; step 3, basic vector action time calculation; step 4, zero vector symmetrical reconstruction of vector sequence; step 5, switch time calculation and register updating; and step 6, PWM signal generation and system closed loop operation. The application realizes full-band suppression of inverter output PWM harmonics by deeply fusing the zero vector symmetrical reconstruction technology and the spread spectrum modulation technology. The application can be applied to a permanent magnet synchronous motor driving system powered by a three-level voltage source inverter, can simultaneously suppress the PWM harmonic amplitude near the odd carrier frequency and the even carrier frequency, effectively reduces electromagnetic vibration and noise, and has extremely high application value in the field of high-power inverters and motor drives.

The application provides a T-type three-level inverter output voltage transient fast compensation method, and relates to the field of power electronic control, which collects three-phase output voltage and current in real time, and obtains voltage vector sequence in two-phase static coordinate system through Clarke transformation. The real-time average radius and offset vector of voltage vector trajectory are calculated through sliding window, the radius deviation rate and offset rate are calculated, and compensation is triggered when any index exceeds the preset threshold. According to the distortion type, the required compensation deviation of each phase is calculated, the compensation priority is determined according to the compensation deviation absolute value, and the single tube compensation is preferentially selected based on the compensation deviation polarity and the phase current direction. When the amplitude is insufficient or the current direction is not matched, the double tube combination is started. The selected switch tube drive pulse is shielded, the switch function is reconstructed to execute compensation, and iteration verification is carried out until the voltage trajectory is restored to be circular. The application is realized by pure software, does not change the original control architecture and topology mode, guarantees the dynamic voltage transient to meet the standard, and does not deteriorate the harmonic quality.

The invention discloses a bus support capacitance calculation method and device, a medium and a product, and relates to the field of power electronics, and the method comprises the steps: firstly, calculating a neutral-point potential fluctuation allowable value according to a three-phase output voltage peak value and a load power factor angle of a three-level inverter; calculating the three-phase output current of the three-level inverter according to the three-phase output current peak value of the three-level inverter; capacitance current flowing through the subintervals is calculated; then calculating the charge cumulant of the bus capacitor in a charging period; and finally, calculating the minimum capacity of the bus capacitor according to the neutral-point potential fluctuation allowable value and the charge cumulant. The technical problem that the capacitance cost and the capacitance volume cannot be effectively reduced due to the fact that the existing method is low in calculation efficiency and difficult to accurately calculate the minimum capacitance capacity on the premise that the output waveform is not distorted is solved.

The application discloses a kind of SVPWM control methods of three-level inverter permanent magnet synchronous motor for electric vehicle, it is related to motor drive and control technical field in electric vehicle high-voltage main drive system, method is: the basic voltage vector of the larger common-mode voltage is discarded to obtain new basic voltage vector diagram;The difference between reference speed and current speed is obtained by outer ring speed PI controller, and q-axis reference current is given d-axis reference current;Three-phase stator current is obtained by Clark and Park conversion d, q-axis component;The α, β-axis component of reference voltage vector is obtained by using deadbeat current prediction control method and through anti-park conversion;The sector where reference voltage vector is located is judged, and the appropriate basic voltage vector is selected based on the new basic voltage vector diagram, the optimal vector combination is selected by value function, and the switching sequence is output in the principle of minimum total switching times, and the inverter is acted on, to drive permanent magnet synchronous motor, improve the energy utilization efficiency of electric vehicle.

A power conversion system includes a power converter including a plurality of switches, one or more capacitors, and a charging connector, wherein the power converter is configured to operate in each of a two-level inverter mode, a three-level inverter mode, a two-level converter mode, a three-level converter mode, an AC-DC onboard charger (OBC) mode, and a DC-DC boost converter mode.

The application discloses a DC bus balance method and device of a three-phase three-level inverter, which can effectively adjust the balance of the DC bus midpoint without sacrificing the performance of the inverter. The application is suitable for the inverter based on the SPWM modulation technology, is simple to realize, and can effectively perform the balance control of the DC bus midpoint under different power factors, and meanwhile, will not reduce the performance of the inverter, including the loss, the ripple, the current distortion rate and the like. The application is suitable for the three-phase three-level inverter with the LCL type filter and the three-phase three-level inverter with the L type filter, and has better compatibility with the hardware system.

The application discloses a short-circuit detection method and circuit for a T-type three-level inverter bridge arm, and the method comprises the following steps: disabling inverter wave generation of an inverter; disconnecting a grid-connected switch between an output end of a bridge arm of the inverter and a power grid, and then reconnecting a switch between the output end of the bridge arm of the inverter and the power grid; judging whether an inverter phase voltage effective value is greater than a preset voltage threshold value within a preset time; disconnecting the switch between the output end of the bridge arm of the inverter and the power grid again, and then reconnecting the grid-connected switch between the output end of the bridge arm of the inverter and the power grid; and judging whether an inductance current effective value is greater than a current threshold value. Therefore, before the T-type three-level inverter is connected to the power grid, whether the switch tube of the bridge arm is short-circuited can be detected by judging whether the inverter phase voltage effective value or the inductance current effective value is greater than the set threshold value, so that effective detection of the short circuit of the T-type three-level inverter bridge arm is realized.

The invention provides a fast modulation type model prediction control method applied to a three-level inverter, and relates to the technical field of inverter optimization control, and the method comprises the steps: carrying out the delay compensation of a converted reference current based on a delay compensation strategy, and combining a converted output current with an optimal voltage vector of a previous control period, thereby achieving the optimal control of the three-level inverter. Therefore, the output current at the next moment is accurately estimated. On the basis, an optimal large sector and an optimal small sector are quickly positioned by introducing a hierarchical query mechanism of a mapping table, an initial optimal voltage vector is screened by utilizing an upper and lower capacitor voltage relationship and combining a cost function minimum principle, then the other two voltage vectors in the small sector are complemented, duty ratio calculation and vector synthesis are completed, and the optimal voltage vector is obtained. Operation efficiency is greatly improved, accuracy and high efficiency of sector positioning and vector selection are ensured through a layered query mechanism of the mapping table, and control precision equivalent to that of a traditional method is maintained while calculation burden is effectively relieved.

The invention provides a neutral-point balance control method of a three-level inverter and the three-level inverter, and belongs to the technical field of inverters. Generating a first / second discontinuous pulse width modulation wave based on an externally input three-phase reference voltage; according to the current midpoint potential deviation state of the three-level inverter and the current space vector sector information of the three-phase reference voltage, weighting coefficients corresponding to the two discontinuous pulse width modulation waves are determined respectively; according to the weighting coefficient, performing weighted fusion on the two discontinuous pulse width modulation waves to obtain a target three-phase modulation wave; and generating a target driving signal based on a comparison result of a preset reference three-phase carrier wave and the target three-phase modulation wave, and sending the target driving signal to a switching tube circuit in the three-level inverter, so that the neutral-point potential of the three-level inverter is balanced. According to the invention, the neutral-point potential balance capability is improved while the switching loss is reduced, so that the system stability and the electric energy quality are improved.

The present application belongs to the technical field of power supply and distribution. A parallel three-level inverter modulation method, system, product, medium and equipment are proposed, which equivalent double parallel three-level inverters as a whole five-level inverter, inject zero sequence components to the initial three-phase reference signal to obtain the reference signal, identify the resultant vector through rounding and remainder operation, and then adjust the reference signal according to the sum of the three-phase state of the initial resultant vector to output a five-segment switching sequence, and then decompose the equivalent five-level reference signal into two sets of three-level reference signals, allocate the reference signals by dividing the half-carrier period and compare them with the triangular carrier to obtain a three-level vector sequence combination. The present application realizes the comprehensive optimization of common-mode voltage, zero-sequence circulating current and output current ripple, avoids complex sector judgment and duty cycle calculation, and reduces the implementation complexity and computational burden.

This invention discloses a control method, apparatus, and device for an ANPC-type three-level inverter, including a three-level inverter circuit. The method includes: firstly, determining whether the inverter is switching from a first mode to a second mode; calculating the collector voltage value based on the DC bus voltage, the bridge arm current of the inverter circuit, a preset stray inductance, and a voltage safety margin; if the collector voltage value is less than or equal to a preset voltage value, and the first mode and the second mode meet a first preset condition, and the junction temperature of the outer transistor is greater than or equal to a first preset temperature, and / or the junction temperature of the clamping transistor connected to the outer transistor is greater than or equal to a second preset temperature, then the inner transistor is turned off and another clamping transistor is turned on; the first preset condition includes the first mode outputting a positive potential, the second mode outputting a zero potential, and the output current being greater than zero, or the first mode outputting a negative potential, the second mode outputting a zero potential, and the output current being less than zero. This method evens out the losses of transistors with higher junction temperatures to the inner transistor, preventing transistor damage.

The embodiment of the invention provides a method and device for adjusting the neutral point potential of a three-level inverter, computing equipment and a medium, and the method comprises the steps: constructing a duty ratio constraint equation of a switching tube in the three-level inverter, and carrying out the solving of the duty ratio constraint equation of the switching tube, the method comprises the following steps: determining duty ratio constraint conditions corresponding to a first switch tube, a second switch tube and a third switch tube, and determining a maximum value and a minimum value of a neutral point current of a three-level inverter; and determining duty ratio target values corresponding to the first switch tube, the second switch tube and the third switch tube, and controlling the operation states of the first switch tube, the second switch tube and the third switch tube through the duty ratio target values so as to adjust the neutral point potential of the three-level inverter. Through the method provided by the invention, the system operation efficiency can be improved.

The invention relates to the technical field of energy storage power supplies, and mainly provides a resonant cavity current control circuit and an energy storage system, the circuit comprises a voltage regulation module, a voltage detection module and a wave sealing control module, the voltage detection module and the voltage regulation module are connected with the voltage regulation module, and the voltage detection module and the voltage regulation module are also connected with a first bus capacitor and a second bus capacitor. And the voltage detection module is used for detecting bus voltages of the two bus capacitors and controlling the voltage regulation module to work when a difference value exists between the two bus voltages so as to regulate the first bus voltage and the second bus voltage. When the voltage regulation module works, the wave sealing control module controls the voltage regulation module to stop working when determining that the current signal of the voltage regulation module does not meet the preset condition. On the basis, bus voltage balance can be realized through the voltage regulation module, so that two LLC paths in the three-level inverter participate in work at the same time, a single LLC path does not need to bear overlarge peak current, the cost is reduced, the service life of the system is prolonged, and the reliability of the system is improved.

A control device (50) is applied to a system including a first power storage unit (21) and a second power storage unit (22), a rotating electrical machine (10) having armature windings (11U, 11V, 11W) corresponding to three phases, and a three-level inverter (30) having switches (SUH-SWL, QU1-QW2), and performs switching control of each switch. The control device includes: a setting unit that sets a drive pattern formed by a combination of drive states of each switch and an occurrence period of each drive state on the basis of a command voltage for controlling a control amount of the rotating electric machine to a command value; and a control unit that performs switching control on the basis of the set driving mode and the occurrence period of each driving state. The setting section sets the driving mode to include at least two of three different zero voltage driving states. The control unit adjusts an occurrence period of each zero-voltage driving state included in the driving mode during the switching control.

The invention belongs to the technical field of inverters, and relates to a parallel three-level inverter zero-sequence circulating current and common-mode voltage cooperative suppression method. Firstly, an evaluation system is constructed on a parallel three-level vector plane, and a parallel three-level vector set conforming to multi-target constraints is screened out; dividing a vector plane into twelve large sectors, and determining sectors and vectors corresponding to each single three-level inverter according to the phase characteristics of the parallel three-phase modulation waves; then, based on sector division of a single inverter, zero-sequence voltage components needing to be injected are calculated in a segmented mode according to the modulation ratio; and finally, injecting the obtained zero-sequence voltage into the modulation wave of each single inverter, and performing staggered carrier distribution on the three-phase modulation wave of the parallel system according to twelve-sector division. The synthesis of the selected parallel three-level vector is realized through the direct comparison of a modulation wave and an interlaced carrier wave, and the modulation is completed; the overall design principle is high in scientific performance, good in feasibility, excellent in inhibition effect and friendly in application environment.

The invention relates to the technical field of inverters, and discloses a neutral-line bridge arm control method of a three-level inverter and the three-level inverter, and the method comprises the steps: obtaining a neutral-line current of the three-level inverter, and carrying out the negation of the neutral-line current to obtain a first modulation signal; obtaining a current given value of the neutral line inductor according to the first modulation signal; acquiring a current real-time value of the neutral-line inductor, and performing feedback regulation based on the current real-time value of the neutral-line inductor and the current given value of the neutral-line inductor to generate a bridge arm control signal; and controlling the midline bridge arm to work based on the bridge arm control signal. Output current required by upper and lower bus capacitors can be reduced, so that the number of capacitors required to be connected in parallel at a direct current side can be reduced, and the cost of the inverter is reduced.

The invention discloses a power distribution method and device for an asymmetric inverter system, equipment and a medium, and the method comprises the steps: obtaining a total voltage modulation wave and a weight factor of the asymmetric inverter system, and carrying out the modulation according to a preset carrier modulation mode; the triangular carrier is converted into an upper carrier and a lower carrier which are used by a three-level inverter, the triangular carrier is converted into an intermediate carrier which is used by a two-level inverter, and in a modulation wave period, when the weight factor is larger than the instantaneous amplitude of the weight triangular wave, according to the amplitude of the intermediate carrier, the triangular carrier is converted into the upper carrier and the lower carrier which are used by the three-level inverter. Clamping the voltage of the two-level inverter to a first maximum voltage modulation wave, and calculating a compensation voltage modulation wave of the three-level inverter according to the total voltage modulation wave; and when the weight factor is smaller than the weight load wave instantaneous amplitude, clamping the voltage of the three-level inverter to a second maximum voltage modulation wave, and calculating a compensation voltage modulation wave of the two-level inverter according to the total voltage modulation wave. Dynamic management of flexible power distribution can be realized.

The invention discloses a protection circuit and a protection device of a T-type three-level inverter, and a vehicle. The protection circuit includes: a power supply; the functional safety logic module is connected with a power supply; the control chip is connected with the function safety logic module; the driving chip is respectively connected with the power supply, the function safety logic module and the control chip, and is connected with an upper bridge transistor and a lower bridge transistor in the three-level inverter; wherein the function safety logic module is configured to receive state signals corresponding to the power supply, the control chip, the upper bridge transistor and the lower bridge transistor; and when the state signal represents that the power supply, the control chip, and the upper bridge transistor and / or the lower bridge transistor have faults, outputting a corresponding safety control signal to the driving chip, so that the driving chip controls the states of the upper bridge transistor and the lower bridge transistor to perform safety protection. By means of the mode, it can be guaranteed that the load connected with the T-type three-level inverter is not out of control.

The invention provides a flywheel-photovoltaic hybrid energy storage system-based network construction type converter control method, and relates to the technical field of network construction type converter control, and the method comprises the steps: firstly carrying out the mathematical modeling of a photovoltaic-flywheel hybrid energy storage system, and then carrying out the deep analysis of the electromechanical characteristics and mathematical representation of a synchronous generator on the basis of the deep analysis of the electromechanical characteristics and mathematical representation of a synchronous generator; a control framework of the virtual synchronous generator is constructed, so that the network-forming converter actively establishes and stabilizes the voltage amplitude and the frequency reference of the alternating current system; and inputting a voltage reference value output by the virtual synchronous generator into an SVPWM modulation module, performing optimization control on the output of the neutral-point clamped three-level inverter by using the SVPWM modulation module, and performing three-phase grid connection on the flywheel-photovoltaic hybrid energy storage system. According to the method, the frequency stability of the power grid can be well improved, the voltage regulation capability is improved, the characteristics of low inertia and weak damping of the micro-grid are improved, and the electric energy quality and reliability of the system are improved.