68 results about "Matrix converters" patented technology

The invention discloses a common-mode electromagnetic interference modeling and suppression method for a matrix converter, and the method comprehensively considers high-frequency parameters and topological characteristics, builds a conduction CM EMI equivalent circuit model of the matrix converter, completes the impedance network fitting of key elements and the extraction of high-frequency parasitic parameters, and achieves the modeling and suppression of the common-mode electromagnetic interference of the matrix converter. The precision of the CM EMI model of the matrix converter is improved, and the analysis of the CM EMI characteristics of the matrix converter is simplified. According to the common-mode electromagnetic interference suppression method for the matrix converter, CM EMI characteristics of the matrix converter are analyzed, a low-attenuation loop in the converter is constructed by adopting a method of combining a neutral line leading-back type structure and increasing output filter capacitor neutral-point-to-ground parasitic capacitance, the propagation proportion of noise in a linear impedance stabilization network measurement branch is reduced, and the measurement accuracy of the common-mode electromagnetic interference suppression method for the matrix converter is improved. And effective suppression of low-cost CM EMI noise is realized on the premise of not depending on an input EMI filter.

The single-phase bidirectional single-stage isolation matrix converter comprises a pre-stage circuit and a post-stage circuit, and the pre-stage circuit comprises an LC filter on the power grid side, a pre-stage single-phase matrix conversion circuit and an LLC resonance circuit with a high-frequency transformer; the post-stage circuit comprises a post-stage conversion circuit and an output filter capacitor; the front-stage single-phase matrix conversion circuit comprises four bidirectional switch assemblies of a full-bridge structure. Each bidirectional switch assembly comprises two unidirectional controllable MOS tubes which are reversely connected in series, one end of each bidirectional switch assembly is connected to an L line or an N line of a power grid, and the other end of each bidirectional switch assembly is connected to the LLC resonance circuit. The rear-stage conversion circuit comprises a bidirectional MOS (Metal Oxide Semiconductor) tube bridge circuit and three high-frequency transformer secondary windings which are in triangular connection or star connection; and two end points of each secondary winding are respectively connected to the upper MOS tube and the lower MOS tube of the corresponding bridge arm and then are connected to output positive and negative ends. The converter has the advantages of high power density, low current harmonic, high power factor and the like, and is small in size, strong in anti-interference capability, wide in buck-boost range, and safe and reliable in commutation.

The invention provides a current stress optimization method and system for an isolated bidirectional three-phase energy storage converter, and relates to the technical field of power conversion. Firstly, Fourier series analysis is carried out on primary and secondary side voltages of a high-frequency transformer, and leakage inductance current and active power are calculated accordingly; carrying out per-unit processing on the active power and the square of the primary side current, and obtaining the active power and the square of the peak current under the fundamental component based on a per-unit processing result; then, with the minimum square of the peak current as an optimization target and the transmission power under the fundamental component as a constraint, constructing and solving a current stress optimization model so as to obtain an optimal matrix converter parameter; and finally, performing current stress optimization control based on the optimal parameters to reduce the current stress. According to the method, the current stress is remarkably reduced while the set transmission power requirement is met, the direct current side dynamic response is improved, and the converter performance is improved.

The present application relates to the technical field of power system relay protection, and particularly relates to a kind of offshore wind power through flexible low-frequency transmission system sending out line protection method, offshore wind farm is connected with modular multi-level matrix converter after being sent out by low-frequency through booster transformer, and is incorporated into large power grid after being frequency converted by M3C. When M3C of offshore wind farm fails, negative sequence current suppression and positive sequence current limiting strategy are adopted for fault ride-through, and relay protection devices are installed at both ends of low-frequency sending out line and communicate. The current sampling values before and after the fault on both sides of the line are reconstructed in phase space, and the difference between the permutation entropies is used to construct a protection scheme, which overcomes the problem of sensitivity reduction of traditional current differential protection for sending out line, reduces the amount of data interaction, and reduces the pressure of protection communication and the requirement of data synchronization. It is not affected by the control strategy of wind turbine and modular multi-level matrix converter at both ends of the line, fault ride-through mode, transition resistance and fault location, and has high reliability and good speed.

The application belongs to the technical field of power electronics, and discloses a double-vector model-free predictive control method for a reduced matrix converter and a related device, the method comprising: obtaining the AC side voltage, DC side voltage and DC side reference voltage data of the reduced matrix converter at a target moment, and calculating the inner loop reference current; obtaining the AC side current and switch input side current of the reduced matrix converter at an adjacent moment, calculating the system gain and system concentrated disturbance of the reduced matrix converter at the target moment, and combining the DC side current of the reduced matrix converter at the target moment to calculate the AC side current at the next moment corresponding to each switch state; and according to the inner loop reference current and the AC side current at the next moment, calculating the action time corresponding to the optimal vector and the suboptimal vector and determining the wave emission mode. The application realizes the model-free predictive control of the RMC, improves the anti-interference of the RMC, and reduces the AC side current ripple through the double-vector fixed-frequency control.

The invention discloses a modular multilevel matrix converter layered architecture device and a control method thereof. The invention discloses a layered architecture device. Comprising a three-phase AC input system, a bridge arm circuit, a three-phase AC output system, a DSP controller circuit, an FPGA controller circuit, an isolation driving circuit, a protection circuit, a starting circuit, an input voltage and current sampling circuit, an output voltage and current sampling circuit, a bridge arm voltage sampling circuit, a bridge arm current sampling circuit, a sampling signal conditioning circuit and an observer. According to the invention, the observation of the capacitor voltage of the M3C bridge arm sub-module is realized by using the observer, the number of voltage sensors and sampling circuits is reduced, the reliability of the system is improved, and the hardware cost is reduced; the hierarchical control method enables the control program to be easy to modify, update and transplant, reduces the workload of developers, and improves the control real-time performance.

The invention provides a matrix converter low-frequency side outer ring reactive power control method and a related device, and the method comprises the steps: carrying out the matching processing based on the obtained operation scene data of the low-frequency side of a matrix converter, determining whether a reactive power control strategy is matched, and if the reactive power control strategy is matched, outputting a reactive power control strategy; if yes, performing coordinate conversion processing on three-phase voltage data and three-phase current data in the operation scene data to obtain voltage conversion data and current conversion data; calculating actual reactive power data based on the voltage conversion data and the current conversion data; performing deviation correction based on the actual reactive power and the obtained reactive power control target data to obtain a deviation correction signal, and performing feed-forward compensation on the reactive power control target data to obtain a feed-forward compensation signal; and performing fusion conversion processing on the feed-forward compensation signal and the deviation correction signal to obtain a control instruction signal, and adjusting the outer loop reactive power of the low-frequency side of the matrix converter based on the control instruction signal. The method improves the operation energy efficiency of the power system.

The invention belongs to the field of direct current transmission system control, and particularly relates to a positive and negative sequence PR modular multi-level matrix type converter circulation control method and a medium. The method comprises the following steps: decoupling a circulating current component from industrial frequency transformer valve side current, low frequency transformer valve side current and bridge arm current of the modular multilevel matrix converter (M3C); according to the phase sequence characteristics of the three-phase bridge arm current frequency, analyzing the current frequency phase sequence characteristics of a circulation component carried in the bridge arm current; according to the current frequency phase sequence characteristics of the circulation component, the circulation component current frequency is obtained, wherein the circulation component current frequency forms a non-single frequency doubled circulation frequency by a power frequency () and a low frequency (); and performing Park change with the sum as a rotation angle on the three-phase bridge arm current, respectively adjusting the three-phase bridge arm current by a PR controller with the sum as a resonant frequency, synthesizing a bridge arm circulating current component through a modulation coefficient and reverse Park change, and continuously iterating to eliminate the circulating current frequency. Therefore, the circulation component in the M3C is inhibited, and the problem of instability in the M3C is solved.

The invention provides a modular multi-level matrix converter topology of a hybrid topology and a modulation method. The modular multi-level matrix converter topology comprises nine bridge arm reactors and nine low-frequency bridge arms, each phase of the low-frequency alternating-current system is respectively connected with three bridge arm reactors in series, the three bridge arm reactors after series connection are respectively connected with three low-frequency bridge arms in series, and the three low-frequency bridge arms after series connection are correspondingly connected with a power-frequency alternating-current power grid. By adopting the hybrid topology, the three-level bridge arm bears part of voltage, the number of cascaded full-bridge modules of the MMC bridge arm is reduced, the equipment cost is further reduced, the problem of high cost of a flexible direct current converter valve is solved, meanwhile, the use amount of power devices is reduced, and the defect that the modular matrix converter has more topological power devices is overcome. According to the modulation method, the mode that the three-level bridge arm and the MMC bridge arm are modulated respectively is adopted, the modulation method is simplified, and the modulation method is easy to implement.

The invention discloses a unilateral matrix converter system for PMSM (permanent magnet synchronous motor) driving application. The unilateral matrix converter system comprises a three-phase input end, a unilateral matrix conversion module, a control module and an output end, the matrix transformation module is composed of a plurality of one-way IGBT power switches, switching is carried out between input phases through a time multiplexing strategy, and direct alternating current to alternating current energy transmission without an intermediate direct current link is achieved. The system adopts a most positive and negative phase selection algorithm and a V / f control strategy, and the output voltage and frequency are adjustable. Compared with a traditional AC-DC-AC system, the AC-DC-AC system does not need a high-capacity capacitor, is simple in structure and low in control complexity, has the energy conversion efficiency as high as 85-90%, has high reliability, light weight and modular expansion capability, and is suitable for aerospace and high-performance motor driving application.

An energy efficiency optimization control method for a single-stage isolation matrix converter is proposed. This method calculates the input current vector magnitude of a three-phase single-stage isolation matrix AC-DC converter, derives the duty cycle expression, minimizes the current stress in the three-phase single-stage isolation matrix AC-DC converter, achieves soft switching, derives the full-bridge phase shift angle expression based on the per-unit value of the input current, designs a single-loop voltage control circuit, does not sample the input current, achieves unity power factor, and keeps the input current sinusoidal.

The invention discloses a three-phase single-stage isolation type matrix conversion circuit and a driving method, and the three-phase single-stage isolation type matrix conversion circuit generates a primary side control quantity and a secondary side control quantity based on a grid side electrical parameter and a DC side electrical parameter, and generates a primary side driving signal and a secondary side driving signal based on the primary side control quantity and the secondary side control quantity respectively. The primary side driving signal drives the three-phase matrix converter, and the secondary side driving signal controls the current of the transformer to be the minimum value in the power frequency period through the full-bridge inverter, so that the current of the transformer in the whole power frequency period can be minimized, and the conduction loss of a device and the loss of the transformer are reduced.

The invention discloses a method for controlling a controlled impedance source of a modular multi-level matrix converter for low-frequency power transmission. According to the control method, on the basis of the idea of a controlled impedance source, the sub-module is equivalently designed to be a frequency division controlled impedance source, energy transfer between impedances is achieved, namely, a power frequency impedance source obtains energy from a power grid, a low frequency impedance source transmits power to a low frequency power transmission system, and therefore stable control over the capacitor voltage of the converter sub-module is guaranteed. And meanwhile, non-communication power frequency / low frequency grid-connected synchronization of the M3C system and self-synchronization among the sub-modules are realized by utilizing the passive synchronization characteristic of the controlled impedance source. The control structure is simple, the information flow of controller interaction and centralized communication can be obviously reduced, and expansion to more quantum modules is easy. According to the control method provided by the invention, the efficiency and safety of the flexible low-frequency power transmission system can be improved, and large-scale grid connection and frequency division power transmission of offshore wind power are realized.

The application discloses a kind of offshore low-frequency wind power transmission line longitudinal protection method and system, after fault occurs, the control strategy of permanent magnet direct drive wind generator net side converter and modular multilevel matrix converter is switched, protection device is collected negative sequence current on line two sides;Wavelet transform denoising is carried out to the negative sequence current collected on line two sides, and mode component is extracted in combination with variable mode decomposition;The energy of each mode component obtained is calculated, and the largest energy characteristic mode is selected;The Hilbert transform is carried out to the selected characteristic mode, and the negative sequence current envelope line is extracted;The slope of negative sequence current envelope line is fitted using least square method;The protection direction identification value of line two sides is determined according to the positive and negative of slope;The protection direction identification value of line two sides is transmitted to the opposite side, when logic criterion F =1 is judged as internal fault, otherwise as external fault, the application meets power grid specification, and the noise resistance is strong, internal fault is sensitive action, and the safety of system is guaranteed.

The application provides a matrix converter system and a control method thereof. The matrix converter system comprises a first output port and a second output port, at least two phases, N converter valve bridge arms, Q first magnetic elements, the i-th first magnetic element comprises N first ports, M second ports, the N first ports of the i-th first magnetic element are connected in series with one end of the N converter valve bridge arms respectively, the other end of the N converter valve bridge arms is connected with any one phase of the first output port respectively, and the other end of at least one converter valve bridge arm is connected with a phase of the first output port which is different from the phase of the first output port connected with the other end of the remaining converter valve bridge arms, and the M second ports of the i-th first magnetic element are connected with any one phase of the second output port respectively, and at least one second port is connected with a phase of the second output port which is different from the phase of the second output port connected with the remaining second ports. i i i i i i ​​​​​​

The application provides a sparse modular multilevel matrix converter topology, a design method and a control method, and the topology has three-phase symmetry on the input and output sides. The design method is for the purpose of reserving the functions and performance of a conventional M3C and reducing the cost, and comprises the following steps: setting the input side and the output side AC frequency of the matrix converter as an integer frequency division relationship; improving the utilization rate of the DC voltage and reducing the modulation amplitude of each bridge arm through a two-side phase coordination control method; and determining the number of bridge arm sub-modules to be less than the number of bridge arm sub-modules of the conventional M3C based on the modulation amplitude. Through the phase coordination technology, the number of bridge arm sub-modules is reduced on the basis of reserving the functions and performance of the conventional M3C, so that the cost is reduced, and the operation efficiency is improved to a certain extent.

The application discloses a C-shaped iron core combined rotary loose coupling transformer, which comprises a fixed assembly and a rotary assembly. The fixed assembly comprises a fixed iron core, first and second fixed windings and a fixed side circuit; the longitudinal section of the fixed iron core is in the shape of a C letter, and the fixed iron core comprises a first fixed iron core, a second fixed iron core and a third fixed iron core; the rotary assembly comprises a rotary magnetic core, a rotary shaft, a rotary bearing, a rotary clamping groove, first and second radial rotary rings, first and second rotary windings and a rotating side circuit; the fixed iron core surrounds the outer periphery of the rotary shaft in the radial direction, and the fixed iron core and the rotary shaft are fixed by the rotary bearing; the first fixed winding and the second fixed winding are connected in series, and the first rotary winding and the second rotary winding are also connected in series. The C-shaped iron core combined rotary loose coupling transformer designed by the application reduces the axial size and weight, improves the power transmission capacity, and first connects the rotating side circuit with a matrix converter.

The present invention discloses a method and system for improving the operational reliability of a flexible low-frequency power transmission system. The method for improving the operational reliability of the present invention comprises: when the number of faulty submodules in a single bridge arm of a modular multi-level matrix converter is greater than the number of redundant submodules, adjusting the reactive power on the power frequency grid side, the reactive power on the low-frequency grid side or the AC voltage amplitude on the low-frequency side, the submodule capacitor voltage and the active power of the new energy power generation system of the modular multi-level matrix converter, so that the modular multi-level matrix converter is not locked and maintains the voltage stability on its low-frequency grid side. The flexible low-frequency power transmission system can continue to operate, significantly improving the reliability of the flexible low-frequency power transmission system. The present invention enables the flexible low-frequency power transmission system to continue to operate when the number of faulty submodules in a single bridge arm of M3C exceeds the number of redundant submodules, thereby improving the operational reliability of the flexible low-frequency power transmission system.

The invention discloses an improved three-level indirect matrix converter with low-voltage ride-through capability and a control method thereof, the converter is composed of an input filter inductor LF, a bidirectional current source rectifier, a T-type three-level inverter and a direct-current link filter capacitor, and through topological structure optimization, the three-level indirect matrix converter with low-voltage ride-through capability is obtained. An input filter capacitor is configured between a rectifier stage and an inverter stage to construct an equivalent voltage source, and the technical challenge that an existing three-level indirect matrix converter cannot maintain load power supply after power grid isolation is solved. According to the low-voltage ride-through control method, additional energy storage elements or hardware circuits do not need to be added, the converter can be controlled to be automatically isolated from the power grid when the low-voltage fault occurs, dynamic energy management is carried out based on inertial energy in a motor load system, and the system is kept to operate continuously within a short time until the fault ends; the motor can stably operate and keep the flux linkage constant during the fault period, and the motor can quickly recover normal operation after the fault is cleared.

This application discloses a method and device for locating faults inside and outside the converter zone of a modular multilevel matrix converter, relating to the field of power electronics. The method includes: acquiring electrical quantity data of the converter zone; calculating the average capacitor voltage of each sub-converter on the power frequency side and low frequency side based on the sub-module capacitor voltage; determining whether a short-circuit ground fault has occurred inside / outside the converter zone based on the zero-sequence components of the power frequency AC voltage and the low frequency AC voltage; if not, determining whether a bridge arm short-circuit fault has occurred based on the sub-module capacitor voltage; if no bridge arm short-circuit fault has occurred, determining whether a phase-to-phase short-circuit fault has occurred inside / outside the converter zone based on the average capacitor voltage of each sub-converter on the power frequency side and low frequency side and the direction of the bridge arm current; if no fault has occurred, determining whether an open-circuit fault has occurred or whether the system is in normal operation based on the sub-module capacitor voltage. This application can distinguish between faults inside and outside the converter zone of a modular multilevel matrix converter, saving fault repair time.

The application discloses a control method for balancing capacitor voltages between bridge arms of a modular multilevel matrix converter, which comprises the following steps: defining relevant electrical quantities related to the modular multilevel matrix converter; defining positive and negative sequence cyclic component forms of low and high frequencies of the modular multilevel matrix converter and control strategies of the cyclic components based on the relevant electrical quantities; adding module capacitor voltages of nine bridge arms of the modular multilevel matrix converter and filtering the added voltages by using a low-pass filter to obtain direct current components of the capacitor voltages of the nine bridge arms; performing double alpha beta 0 transformation on the direct current components of the capacitor voltages of the nine bridge arms to obtain eight u Cαβ0 / αβ0 components; controlling the eight u Cαβ0 / αβ0 components based on the positive and negative sequence cyclic component forms of low and high frequencies and the control strategies of the cyclic components to obtain four groups of sequence cyclic components of the nine bridge arms, and then adding the four groups of sequence cyclic components to obtain voltage modulation waveforms of the cyclic components of the nine bridge arms.

The invention discloses a harmonic control method based on an isolated matrix converter, and relates to the technical field of power electronics, and the method comprises the steps: carrying out the phase-locked loop and coordinate transformation processing of a sampled network-side voltage and a sampled network-side current, and obtaining the network-side input quantity of a harmonic controller; sampling a direct current side voltage and a direct current side current as direct current side input quantities of the harmonic controller; based on the grid side input quantity and the direct current side input quantity, the reference current and the reference reactive power are combined, a harmonic controller is used for compensating power deviation, and the duty ratio and the phase shift angle are obtained; based on the duty ratio and the phase shift angle, driving signals of all switching tubes in the matrix circuit are obtained through a pulse width modulation controller, and driving signals of all switching tubes of a full bridge are obtained through a phase shift controller. According to the invention, through double-loop control of the DC side current outer loop and the power inner loop, the current waveform of the AC side is optimized, and when the power fluctuates, the control variable can be rapidly adjusted, and the harmonic content of the AC side is reduced.

This invention provides an explosion-proof and automatically cooling low-voltage power supply device, belonging to the field of power supply equipment technology. It includes mechanical and electrical components. The mechanical component includes a power supply main body, while the electrical component includes a multi-functional power analysis module, a data acquisition module, a matrix converter, an isolation transformer, an intelligent power switch module, and an energy storage power supply module, all housed within the power supply main body. The power supply main body has a dividing vertical plate that separates its interior into a first installation area and a second installation area. When the temperature rises, a thermistor triggers the power supply to operate. The power supply supplies power to a cooling fan for heat dissipation and simultaneously opens an explosion-proof valve. This design effectively prevents the risk of explosion due to excessive temperature and, in the event of an explosion, inhibits its propagation. An explosion-proof heat dissipation component is installed in the second installation area to facilitate overall heat dissipation.

The invention provides a bridge arm capacitor voltage control method, a bridge arm capacitor voltage control system and a storage medium. The bridge arm capacitor voltage control method comprises the following steps of performing coordinate conversion processing on an acquired bridge arm capacitor voltage instantaneous value of a matrix converter to obtain a voltage unbalance initial component; classifying the voltage unbalance initial components according to frequency characteristics, and configuring wave filtering parameters based on the voltage unbalance initial components with different frequency characteristics to perform ripple suppression processing to obtain voltage unbalance first components; inputting the voltage imbalance first component into a PI controller to generate a branch bridge arm power reference value; adjusting a branch bridge arm power reference value based on a phase transformation matrix of the matrix converter to generate a basic circulating current component and a ripple compensation circulating current component; performing fusion correction on the basic circulating current component and the ripple compensation circulating current component based on actual operation data to obtain a circulating current control instruction; and controlling the bridge arm capacitor voltage of the matrix converter based on the annular control instruction signal. According to the method, ripple accumulation is effectively avoided, and power switch tube loss is reduced.

The application relates to the field of power electronics, in particular to a hybrid commutation method and system. The hybrid commutation method is used for the commutation of a current source type matrix converter, and the method comprises the following steps: using a 2 / 3 PWM modulation mode to alternately control the turn-on and turn-off of the upper switch tube or the lower switch tube of any two phases of A phase, B phase and C phase of the current source type matrix converter, and meanwhile making the lower switch tube or the upper switch tube of the remaining one phase in a clamping state; obtaining the voltage difference between the upper switch tube or the lower switch tube of the any two phases; when the voltage difference is greater than a preset voltage threshold, using a voltage type commutation mode to control the switching sequence of the upper switch tube or the lower switch tube of the any two phases. Sensor-free, reduced hardware cost and complexity: the method replaces real-time sensor detection through sector prediction and current change rule calculation, and high-bandwidth current sensors and precise voltage detection circuits are omitted, so that the system hardware cost is reduced.

The invention provides a method and a device for acquiring harmonic equivalent impedance of a modular multilevel matrix converter. The method comprises the following steps: defining positive sequence impedance and negative sequence impedance of an M3C in a three-phase symmetric operation state; applying a voltage disturbance in a set range of an M3C steady-state working point, and calculating a bridge arm reference voltage disturbance harmonic wave caused by the voltage disturbance in a dq coordinate system; obtaining a phasor form of a bridge arm reference voltage disturbance harmonic wave under an abc coordinate system through coordinate transformation; establishing a KCL equation for a bridge arm connecting the power frequency side and the low frequency side and carrying out linearization processing to obtain a disturbance voltage generated after the disturbance current is responded by the controller; simplifying a bridge arm voltage and current relation based on the disturbance voltage to obtain a unified disturbance voltage vector and disturbance current expression; and on the basis of the disturbance voltage vector, the current expression, the positive sequence impedance and the negative sequence impedance, the M3C positive sequence impedance seen from the power frequency side and the low frequency side is obtained through derivation by adopting per unit values.

The invention relates to the technical field of rectifiers, and provides an active clamping three-phase high-frequency link matrix rectifier and a pulse width modulation method thereof.The active clamping three-phase high-frequency link matrix rectifier comprises a three-phase alternating-current power supply, an LC input filter, a matrix converter, a high-frequency transformer, an uncontrolled rectifier bridge, an output filter and a load which are connected in sequence; an active clamping circuit is connected in parallel between the uncontrolled rectifier bridge and the output filter; each of the upper and lower bridge arms of each phase of the matrix converter comprises two switching tubes which are reversely connected in series. Based on the topology, the resonance process characteristics of the parasitic capacitance of the secondary side diode and the leakage inductance of the transformer are combined, and the high voltage stress generated by the leakage inductance of the transformer and the oscillation of the parasitic capacitance of the secondary side diode is suppressed by driving the auxiliary switch Saux on the premise of ensuring the output quality.

The invention discloses an M3C bridge arm voltage output capability determination method, system and device and a medium, and belongs to the technical field of power electronics, a single bridge arm loop model of a modular multi-level matrix converter M3C is established, a single bridge arm loop voltage expression is deduced, and a single bridge arm is formed by connecting a plurality of cascaded full bridge sub-modules and a bridge arm inductor in series; the method comprises the following steps: splitting a single-bridge arm loop voltage into a power frequency component and a low frequency component by neglecting a circulating current influence, and respectively establishing a power frequency side three-phase simplified loop and a low frequency side three-phase simplified loop; determining a power frequency side no-load modulation degree based on the voltage transmission characteristics of the power frequency side three-phase simplified loop; determining a low-frequency side no-load modulation degree based on the voltage transmission characteristics of the low-frequency side three-phase simplified loop; and obtaining a power frequency side phase voltage peak value and a low frequency side phase voltage peak value, and calculating the voltage output capability of the M3C bridge arm according to the power frequency side no-load modulation degree and the low frequency side no-load modulation degree.

The invention discloses a neural network prediction control method for a modular multilevel matrix converter, and belongs to the field of power electronics. The M3C is a power electronic topology for realizing direct alternating current-alternating current electric energy conversion, and has the advantages of modularization, flexible control, high electric energy quality and the like. A traditional FCS-MPC needs to traverse all possible switch state combinations in a control period, huge calculation burden is caused, meanwhile, the control precision of the FCS-MPC depends on the accuracy of a mathematical model, and robustness is poor. The invention provides a neural network predictive control method for M3C, and the method comprises the steps: collecting the input and output data of an FCS-MPC controller under different working conditions, carrying out the offline training of a neural network through the collected data, replacing the FCS-MPC with the trained network, and carrying out the real-time control, and also provides a delay compensation scheme of the method. According to the method, the online calculation burden of the digital controller is greatly reduced, and disturbance of M3C system parameters is introduced in the training process of the neural network, so that the neural network prediction controller has higher adaptability to parameter changes, and the robustness of the control system is further improved.