272 results about "Three level inverter" patented technology

The invention discloses a method for diagnosing an IGBT open-circuit fault and a current sensor fault of a T-type three-level inverter, belongs to the technical field of inverter fault diagnosis, and is used for solving the problems of diagnosis and positioning when a three-level T-type inverter IGBT switch tube and a sensor have faults. Comprising the following steps: classifying and marking and numbering fault types of an open-circuit fault of a T-type three-level inverter IGBT and a fault of a current sensor; fault samples are collected and divided into a training set and a test set according to the proportion of 7: 3; a TCN-LSTM-SelfAction fault diagnosis model is constructed, and model training is carried out by using the training set; the trained model is used for evaluating the accuracy of fault type diagnosis of the training set and the test set. According to the diagnosis method, the fault types and the fault positions of the IGBT open-circuit fault and the current sensor fault can be diagnosed at the same time, the TCN and the LSTM are selected to be combined, local information and global relation of fault features can be captured at the same time, and meanwhile, the performance of a model is improved by combining a self-attention mechanism in the LSTM, and the accuracy is improved.

The invention discloses a three-level inverter dual-tracking model prediction control method and an inverter, and the method comprises the steps: constructing an integral sliding mode observer, and obtaining a current prediction value and a lumped disturbance estimation value through the integral sliding mode observer; calculating a voltage error of the inverter, and substituting the voltage error into the PI controller to obtain a voltage tracking control item; based on the voltage tracking control term, a switching state that minimizes the cost function is selected to control the inverter. The integral sliding mode observer is configured to calculate a current prediction error between a current prediction value of a current control period and a system output current, introduce an integrator to track the current prediction error, and generate an error function based on an output result of the integrator and the current prediction error. And feeding back a current predicted value and a lumped disturbance estimated value of the next control period through an error function. According to the invention, the method can achieve the quick estimation of the operation state of the inverter and the robust compensation of disturbance, reduces the steady-state tracking error, and reduces the total harmonic distortion of the inverter.

The invention relates to the technical field of inverter pulse width modulation, in particular to a neutral-point potential balance and low common-mode voltage modulation method and system based on an SVPWM inverter, and the method comprises the steps: determining a basic voltage vector based on different switching states of an NPC three-level inverter; respectively determining the midpoint current of each fundamental voltage vector, and determining the fundamental voltage vector causing midpoint potential deviation; combining with a large vector and a zero vector, and performing mode division of a single vector space region; determining an expected current according to the DC side capacitor voltage of the inverter, and constructing a target function based on the expected current; and performing region judgment according to the output synthesized voltage vector, determining a corresponding optimal division mode, obtaining each basic voltage vector of the synthesized voltage vector and a corresponding duty ratio, and determining a switching sequence to obtain a PWM wave. While the neutral-point potential balance and common-mode voltage suppression of the NPC three-level inverter are realized, the switching frequency of the inverter is effectively reduced, and the switching loss is reduced.

The present invention provides a method for cooperatively suppressing a common-mode voltage and current harmonics of coupled three-level inverters, comprising: based on amplitude and phase angle of reference voltage vector, determining sector and region in which the reference voltage vector is located; selecting four basic voltage vectors with low common-mode voltage amplitudes to synthesize the reference voltage vector; writing volt-second balance equation based on selected basic voltage vectors, and calculating duty cycles thereof; and based on sector and region in which reference voltage vector is located, set value of voltage difference across capacitors on direct current side, and actual value of voltage difference across capacitors on direct current side, (1) updating duty cycles of basic voltage vectors, to realize separate control of capacitor voltage; and (2) designing and converting switching sequence into PWM drive signal of power switch, to control the coupled three-level inverter to operate.

The invention discloses a multi-target robust model predictive control method for a permanent magnet synchronous motor, which is used for a three-level inverter power supply permanent magnet synchronous motor system with a quadruple BOOST booster circuit, and comprises the following steps: firstly, carrying out system modeling and discretization, then carrying out multi-target cost function design, solving a multi-target optimization problem based on compromise programming and a fuzzy decision method, and finally, carrying out multi-target robust model predictive control on a three-level inverter power supply permanent magnet synchronous motor system with a quadruple BOOST booster circuit. And calculating a delay compensation strategy and a robustness enhancement measure, and finally calculating the output voltage of the quadruple Boost circuit and the output voltage of the inverter. The method improves the DC bus voltage, improves the output power and efficiency, enhances the robustness of the system to parameter change and uncertainty, realizes multi-target optimization control, ensures that the system stably and efficiently operates under complex working conditions, and is suitable for the fields of speed regulation of motors with booster circuits and the like.

The invention discloses a current harmonic suppression method, device and equipment of a T-type three-phase three-level inverter and a readable storage medium, and relates to the technical field of power electronics. Comprising the steps of obtaining an upper capacitor voltage and a lower capacitor voltage of the T-type three-phase three-level inverter, and determining a target control set according to a relation between the upper capacitor voltage and the lower capacitor voltage; for each candidate vector voltage in the target control set, calculating a cost value corresponding to each candidate vector voltage; and taking the candidate vector voltage corresponding to the minimum cost value as a target vector voltage. According to the method provided by the invention, the effective suppression of the current harmonics of the T-type three-phase three-level inverter is realized.

The invention discloses a control method, device, equipment and product of a dual three-level inverter, and the method comprises the steps: obtaining a zero-sequence current and a neutral-point potential in the dual three-level inverter when the dual three-level inverter operates; traversing all selectable clamping combinations, and calculating the zero-sequence voltage of the dual three-level inverter and the neutral-point current of the dual three-level inverter which are correspondingly generated; and selecting the corresponding clamping combination when the positive and negative directions of the zero-sequence voltage and the zero-sequence current are opposite and the positive and negative directions of the midpoint current and the midpoint potential are opposite as the clamping combination selected by the first three-level inverter and the second three-level inverter. According to the dual three-level inverter, the appropriate clamping combination of the first three-level inverter and the second three-level inverter can be selected, zero-sequence current suppression and neutral-point potential balance in the dual three-level inverter are achieved, the output performance of the dual three-level inverter is improved, meanwhile, the switching action frequency of the dual three-level inverter can be reduced, and therefore switching loss is reduced.

The invention provides a phase delay error suppression method for a midpoint current sensor of a T-type three-level inverter, and the method comprises the steps: determining a sector and a sub-region where a target voltage vector is located according to the input target voltage vector, selecting a basic voltage vector for synthesis according to the sub-region where the target voltage vector is located, calculating the action time of the voltage vector, and calculating the phase delay error of the midpoint current sensor of the T-type three-level inverter. The switching time of the seven-segment switch is determined, so that a seven-segment PWM switching signal is generated; judging whether the target voltage vector is located in an unobservable area according to the action time of the basic voltage vector; if yes, maintaining the original seven-segment PWM switching signal to send waves; otherwise, adjusting the seven-segment PWM switching signal, and compensating the observable voltage vector which does not meet the minimum sampling time by shifting the PWM signal to obtain a plurality of stable current sampling windows; and phase delay error compensation of the reconstructed three-phase current is realized according to the relationship between the sampling currents. According to the method, the distortion of the reconstruction current is improved, so that the precision of the three-phase reconstruction current is effectively improved.

The invention discloses a cooperative control method for neutral-point balance and circulation suppression of an inverter. The method comprises the following control steps: collecting three-phase current of a power grid side, and generating a three-phase bridge arm modulation signal through a grid-connected current control loop; collecting a lower half bus voltage and generating a first zero-sequence component through a neutral-point balance control loop; collecting three-phase current on the power grid side, and generating a second zero-sequence component through a circulating current suppression control loop; inputting the first zero-sequence component and the second zero-sequence component into a competition logic processing module, and generating a final zero-sequence component by using a competition mechanism based on dynamic weight distribution; and the final zero-sequence component is subjected to over-modulation processing and then superposed to a three-phase bridge arm modulation signal of a grid-connected current control loop, and then a control signal of the three-level inverter is obtained after PWM (Pulse-Width Modulation). The method has the advantages that by dynamically coordinating the midpoint balance and circulating current restraining requirements, efficient coordination of the midpoint balance and the circulating current restraining requirements can be achieved, the control complexity is reduced, and the method is suitable for low-cost industrial application scenes.

The invention discloses a fault diagnosis method, device and equipment for an NPC three-level inverter and a medium, and relates to the technical field of inverter fault diagnosis, and the method comprises the steps: building a fault stator current analysis model according to a fault stator current change rule of the inverter; a fault phase and a fault bridge arm are extracted and positioned by using a sliding window averaging method; and calculating and setting a fault positioning reference value under an ideal condition, and comparing the fault positioning reference value with a fault positioning actual value under an actual condition to position a faulted IGBT (Insulated Gate Bipolar Translator). A fault stator current analysis model is established to simulate a set current change condition under an ideal condition, a fault positioning reference value is calculated, and whether an actual fault condition is consistent with a set ideal fault condition is distinguished by a deviation between the fault positioning reference value and a fault positioning actual value of an actual condition, and whether a fault is an inner pipe or an outer pipe is positioned. During calculation, a current mean value from a fault moment to a first zero-crossing moment is utilized, a fault IGBT can be positioned in a fundamental wave period, and fault diagnosis and positioning can be quickly and efficiently carried out.

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 discloses a vector reconstruction harmonic suppression method for a three-level inverter power supply permanent magnet synchronous motor, and relates to the technical field of motor harmonic and noise suppression. Calculating action time of three basic vectors, selecting the three basic vectors, adjusting an original vector synthesis sequence in a single carrier period into a vector reconstruction synthesis sequence, calculating three time nodes of a fifth-segment sequence and a sixth-segment sequence according to the original vector synthesis sequence, and calculating the time nodes of the fifth-segment sequence and the sixth-segment sequence; the action duration of the two basic vectors after adjustment is calculated according to the vector reconstruction synthesis sequence, the numerical value of a switching time node of a three-level inverter switching tube is updated according to the action duration, and the assigned value of a time register is calculated and updated in a circulating mode in the operation process of the permanent magnet synchronous motor system. And generating a PWM (Pulse Width Modulation) driving signal to control a three-level inverter switching tube to drive a motor. Improvement is carried out based on a traditional SVPWM technology, the high-frequency harmonic performance of the three-level inverter and the motor driving system can be remarkably improved, system cost and operation difficulty do not need to be increased, and the method is simple and easy to implement.

The invention discloses an optimized virtual vector modulation strategy of a T-type three-level inverter, which is characterized in that a sector is re-divided based on the virtual vector modulation strategy, a synthesis mode of a virtual vector is optimized, a low-amplitude common-mode voltage vector is adopted to synthesize the virtual vector, on one hand, common-mode voltage generated by the inverter can be inhibited, and on the other hand, the common-mode voltage generated by the inverter can be inhibited; and on the other hand, the optimized modulation method does not influence the neutral point potential, the smoothness of the direct output voltage of the inverter is improved, the voltage quality is improved, and the method has the advantages of low harmonic content of the output current and the like. In addition, the method solves the problems of inverter output voltage distortion, common-mode voltage spike and the like caused by a dead zone effect through a voltage vector compensation method, and has guiding significance for improving the reliability of a photovoltaic system and a micro-grid system.

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 discloses a T-type inverter fault diagnosis method based on a CWGAN and a TCN-SE network, relates to the fault diagnosis technology of power electronic equipment, and provides the scheme for solving the problem that the diagnosis precision is limited in the prior art. Acquiring three-phase current signal data output by the load side of the T-type three-level inverter; performing time sequence feature extraction on the three-phase current signal data through a TCN-SE network; wherein the TCN-SE network comprises a plurality of time sequence convolution modules, an SE attention module and a full connection layer, and the time sequence convolution modules adopt a one-dimensional convolution kernel to perform feature extraction on an input sequence; enhancing the original fault sample based on the CWGAN; inputting the features extracted by the TCN-SE network into a classifier for fault identification, wherein the classifier outputs the probability of each type of fault by adopting a Softmax function; the method has the advantages that the fault diagnosis accuracy is improved; the robustness and generalization ability are enhanced; self-adaptive extraction of time sequence features is realized; the small sample training effect is optimized; the diagnosis efficiency is 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 relates to a control method of a three-level inverter, a motor driver and a vehicle. The control method comprises the following steps: acquiring a first voltage at two ends of a first bus capacitor, a second voltage at two ends of a second bus capacitor, a reference current of the three-level inverter and a modulation voltage corresponding to each phase line on the alternating current side of the three-level inverter; determining an initial accumulated charge based on the first voltage and the second voltage; determining a zero-sequence injection voltage based on the reference current, the modulation voltage corresponding to each phase line and the initial accumulated charge; determining a target modulation voltage corresponding to each phase line according to the modulation voltage corresponding to each phase line and the zero-sequence injection voltage; and outputting a target modulation signal to the three-level inverter according to the target modulation voltage. Obviously, the probability of midpoint voltage deviation can be effectively reduced through the zero-sequence injection voltage, interference in the control process of the three-level inverter is reduced, the output quality of the target modulation signal is improved, and the control efficiency of the three-level inverter is improved.

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 method for realizing switching loss optimization based on DPWM and VSV under a load condition, and the method comprises the steps: converting a T-type three-level inverter space vector diagram under an a-b-c coordinate system into an alpha-beta coordinate system, and obtaining the closest three vectors of a synthetic reference voltage vector Vref and the acting time of the closest three vectors; therefore, a foundation is laid for calculating the neutral-point charge Q1 with the clamping position being positive level and the neutral-point charge Q2 with the clamping position being negative level in the current switching period; then, according to a circuit topology structure of the T-type three-level inverter, obtaining a midpoint current corresponding to each vector in the positive and negative small vector switch sequences of each small sector; and finally, judging whether the reference voltage vector Vref is in a controllable region of DPWM neutral-point potential balance or not according to a sign of a product of a neutral-point charge Q1 clamped at a positive level and a neutral-point charge Q2 clamped at a negative level in a switching period when the reference voltage vector Vref is located in the small sector. And if yes, determining the capacitor voltage Udc1 of the upper bus and the capacitor voltage Udc1 of the lower bus at the direct current side of the T-type three-level inverter.

The invention relates to a non-intrusive three-level inverter phase current reconstruction method based on a fixed sampling moment, and belongs to the technical field of permanent magnet synchronous motor control. Aiming at the problems that the sampling time is not fixed, blind areas exist in a low modulation area and a sector boundary, and harmonic waves are increased due to intrusive compensation in current reconstruction of an existing three-level inverter, redundant small vectors at the starting moment and the center moment of a carrier are adopted as effective reconstruction vectors, and a single-sensor topology of a coupling phase current and a midpoint capacitance branch is designed; and a zero vector group is used for replacement in a low modulation region, so that non-intrusive fixed sampling is realized. The method covers all areas except an overmodulation area in a hexagonal space voltage vector contour, the reconstruction error is smaller than 5%, the bus utilization rate reaches 95%, a complex compensation algorithm is not needed, and harmonic and switching loss is reduced.

The application discloses an improved zero-error current predictive control method based on a Jury criterion, and specifically comprises the following steps: step 1, collecting the grid-side inductance current of a T-type three-level inverter and the voltage at a grid connection point, and constructing a mathematical model in an alpha-beta coordinate system; step 2, performing forward Euler discretization on the model constructed in step 1 to obtain a reduced zero-error current predictive control model; step 3, performing prediction on the control model obtained in step 2 by using Newton interpolation to obtain predicted current and voltage; step 4, converting the predicted results obtained in step 3 to obtain the output voltage of the inverter; step 5, solving the value range of lambda by using the Jury criterion; and step 6, according to the solving result of step 5, using a pulse signal to drive the on-off of the switching tube in the inverter. The application solves the problem that the existing zero-error current predictive control has low precision and dynamic performance.

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 present invention is applicable to the technical field of inverters, and provides a midpoint active clamped three-level inverter, a control method and a control device. The midpoint active clamped three-level inverter includes: a bridge arm unit, a clamping unit connected to the bridge arm unit, and a bridge arm output end connected to the bridge arm unit; the bridge arm unit includes a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a first diode, a second diode, a third diode and a fourth diode connected in anti-parallel to the first switch tube, the second switch tube, the third switch tube and the fourth switch tube; the clamping unit includes a fifth switch tube, a sixth switch tube, a fifth switch tube and a sixth diode connected in anti-parallel to the sixth switch tube; the fifth diode and the sixth diode are silicon carbide diodes. The present invention can reduce uneven heating of each switch tube and improve the efficiency and stability of electric energy conversion.

The utility model discloses a grid-connected inverter system and power generation equipment. The grid-connected inverter system is used for being connected between a bus and a grid-connected point, and comprises a plurality of neutral-point-clamped three-level inverters and a plurality of filter circuits, wherein alternating current sides and direct current sides of the neutral-point-clamped three-level inverters are respectively connected in parallel; the positive half bus access end and the negative half bus access end of the neutral point clamping type three-level inverter are respectively connected with the positive end and the negative end of the bus; an inversion output end used for outputting voltage in the neutral point clamping type three-level inverter is connected with a filtering input end of a filtering circuit, so that the voltage output by the inversion output end is filtered by the filtering circuit and then is output by a filtering output end of the filtering circuit; a voltage output end formed by connecting the filter output ends of the filter circuits for outputting the same phase voltage in all the filter circuits is connected with a grid-connected point; and bus midpoints of all the midpoint clamping type three-level inverters are connected. According to the technical scheme disclosed by the utility model, the operation stability of the grid-connected inverter system can be improved.

An inverter circuit is a three-level inverter circuit. The inverter circuit comprises: a P busbar (71) connected to a high-potential terminal of a battery, an N busbar (72) connected to a low-potential terminal of the battery, and an M busbar (73) with a potential between the P busbar (71) and the N busbar (72). The inverter circuit also includes: a PM capacitor (30) connected to the P busbar and the N busbar, an MN capacitor (40) connected to the N busbar and the M busbar, and a semiconductor device (20) connected to the M busbar.The M busbar is a part between (i) the second power module (20) and (ii) the PM capacitor and the MN capacitor, is arranged between the P busbar and the N busbar and has a base section (73a) opposite the P busbar and the N busbar.

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.