10results about How to "Improve waveform quality" patented technology

The invention relates to the technical field of three-phase three-level NPC converter control, in particular to a three-level converter full control set model prediction control method, which comprises the following steps: constructing a first prediction model of a three-level converter based on an electrical physical quantity; equally dividing each control period into n identical state intervals to form a full control set; converting the full control set after the redundant vector is removed into an alpha-beta coordinate system; obtaining a second prediction model under the alpha-beta coordinate system under the action of the full control set; constructing a midpoint potential difference prediction model; establishing a cost function by using the two prediction models; and carrying out hierarchical optimization on the cost function, removing redundant vectors from the full control set, carrying out cost function calculation, and selecting a state vector which enables the cost function to be minimum from the full control set as an optimal vector of a corresponding control period. According to the three-level converter neutral-point potential balancing method, a hierarchical optimization method is utilized, the neutral-point potential balancing problem of the three-level converter is solved, meanwhile, the tedious weight factor design step is eliminated, and the calculation burden is reduced.

This application relates to the field of microgrid technology, and in particular to a current harmonic suppression method, an inverter, and a storage medium. The method includes: establishing the state equation of the grid-connected inverter based on the grid-connected inverter circuit and Kirchhoff's laws; establishing a transfer function from the disturbance voltage to the harmonic components of the grid-connected current based on the state equation; determining a calculation model for the modulation wave compensation term used to suppress the disturbance voltage based on the transfer function; extracting the harmonic components in the grid-connected current in real time, and obtaining the modulation wave compensation signal based on the calculation model of the harmonic components and the modulation wave compensation term; and superimposing the original modulation wave signal output by the current loop controller and the modulation wave compensation signal to obtain the final modulation wave signal. The method of this application can actively and accurately compensate for periodic voltage disturbances introduced by the switching of the power frequency bridge arm, thereby effectively suppressing the resulting current harmonics and zero-crossing distortion, and significantly reducing the THD of the grid-connected current.

The application discloses a front-stage inductance switching circuit, an H-type multi-level current source type inverter with current self-balancing capability and a modulation method thereof, a storage medium and equipment, and relates to the technical field of power electronics. The application comprises a switching branch and a direct-current energy storage inductor. In series mode, a first group of the switching branches and a third group of the switching branches are turned off, a second group of the switching branches is turned on, two direct-current energy storage inductors are connected in series, and two inductor currents are forced to be equal to automatically eliminate current deviation, so that the inverter outputs three-level current. In parallel mode, the second group of the switching branches is turned off, the first group of the switching branches and the third group of the switching branches are turned on, the two direct-current energy storage inductors are connected in parallel, the inverter outputs three-level current, and the output current amplitude is twice that in the series mode. Compared with the prior art, the application utilizes the inherent series current sharing characteristic of the circuit topology, solves the current imbalance problem caused by inconsistent inductance parameters, and has good self-balancing capability.

The application discloses a wide-spectrum microwave generating system based on a magnetic switch, and aims at solving the problems of the existing wide-spectrum microwave generating system, such as difficulty in realizing high repetition frequency, long service life, stable operation and miniaturization. The application is composed of a primary power supply U0, an energy storage capacitor CC, a magnetic switch and a load antenna R. The switching of the magnetic core working state between the forward saturation point and the reverse saturation point is used to complete the current diversion on the winding of the magnetic switch, so as to generate wide-spectrum pulse oscillation on the load antenna, realize the miniaturization and compactness of the wide-spectrum microwave generating system, and effectively improve the repetition frequency operation ability and long service life working ability of the wide-spectrum microwave system by relying on the characteristics of high repetition frequency and long service life of the magnetic switch. The application does not need to use a pulse forming line to generate wide-spectrum oscillation, and is beneficial to realize the solidification and compactness of the wide-spectrum microwave system. The application uses the magnetic switch as a main switch, and greatly improves the service life of the wide-spectrum microwave system.

This invention discloses a method, system, controller, and medium for suppressing unbalanced MMC circulating current, relating to the field of MMC control. The method includes: acquiring three-phase voltage parameters, three-phase current parameters, and grid angular frequency of the MMC; performing phase sequence decomposition on the three-phase voltage parameters, three-phase current parameters, and grid angular frequency to obtain the positive-sequence and negative-sequence components of the three-phase voltage and three-phase current; using a PI controller to perform inner-loop regulation on the positive-sequence and negative-sequence components of the three-phase voltage and three-phase current, outputting the positive-sequence and negative-sequence reference components of the three-phase voltage in a synchronous rotating coordinate system; performing inverse transformation of the positive-sequence and negative-sequence reference components of the three-phase voltage according to the grid angular frequency, and adding the results of the inverse transformation to obtain the three-phase voltage reference components; performing carrier phase-shift modulation on the three-phase voltage reference components to generate the port levels required for each phase arm, and controlling the operating state of the IGBTs in each phase arm submodule of the MMC based on the port levels.

The invention discloses a portable AC-DC voltage converter which comprises an AC-DC input loop, a charging module, a lithium battery, an inversion module, an isolation boosting transformer, a central processing unit control unit, a touch screen and an output relay. The input loop charges the lithium battery through the charging module, the lithium battery provides a power supply for the isolation boosting transformer through the inversion module, the boosting transformer outputs multi-stage alternating voltage and distributes the multi-stage alternating voltage to a load through the output relay, and the central processor control unit acquires parameters such as voltage and current in real time based on neural network prediction and fuzzy control rules. The SPWM signal modulation duty ratio of the inversion module is dynamically adjusted, and stable voltage output is achieved. Multi-power-supply compatibility is achieved through the alternating current and direct current self-adaptive charging module, the dynamic response capacity and control precision are improved through neural network predictive control, the voltage stability is ensured through fuzzy control rules, the functions of overload protection, short circuit protection and real-time adjustment are achieved, and the application range is wide.

The utility model discloses a three-phase program-controlled alternating current power source, which relates to the field of three-phase program-controlled alternating current power sources and comprises a digital DSP (digital signal processor) controller + large-scale FPGA (field programmable gate array) module, a three-phase alternating current power output module, a three-phase remembered sine wave generating circuit, a touch screen, a liquid crystal display module, a low-pass filter A, a low-pass filter B and a low-pass filter C, and the touch screen and the liquid crystal display module are connected with the digital DSP controller and the large-scale FPGA module. According to the utility model, the three-phase power source adopts a DSP + FPGA technology, a large-scale FPGA with powerful and flexible functions, an internal and external phase-locked closed-loop control technology, a high-speed and high-precision D / A and a high-fidelity power amplifier to form a new-generation high-precision standard power source, the frequency stability is high, the continuity is good, the precision of output voltage and current can reach 0.01 level, and a single-phase 0-380V, three-phase three-wire, high-precision and high-precision standard power source can be provided. And the three-phase four-wire alternating current voltage is 0-380V.

The invention discloses a solid-state pulse power supply system of a field anti-configuration device and a time sequence control method of the solid-state pulse power supply system. The solid-state pulse power supply system comprises a multiplex load coil, and a bias branch, an ionization branch, an anti-field branch and a steady-state branch which are connected to the two ends of the coil in parallel. A main switch of each branch circuit adopts a solid-state switch element, natural follow current is realized by using a diode or a bidirectional structure in the branch circuit, and an independent follow current branch circuit is thoroughly canceled. Meanwhile, in cooperation with a microsecond time sequence control method, a steady-state branch circuit is conducted in advance to excite the reactor to form virtual impedance, and pure physical series voltage division protection is achieved. According to the invention, full time sequence multiplexing of the coil function is realized, the stray inductance, the size and the cost of the system are reduced, kHz-level repetition frequency operation can be supported, and the reliability and the stability of the field inversion configuration device are obviously improved.

The present invention discloses a test device for the dynamic response of a suspended tunnel under the action of wind-wave-current coupling, comprising a simulation mechanism, a suspended tunnel test mechanism and a measuring mechanism, wherein the simulation mechanism is used to simulate a wind field and control water movement, and can simulate the excitation action of wind-wave-current coupling; the suspended tunnel test mechanism is used to simulate the dynamic response of a suspended tunnel under the excitation action of wind-wave-current coupling and conduct tests; the measuring mechanism is used to measure, collect and feedback test data of the simulation mechanism and the suspended tunnel test mechanism. The present invention can flexibly simulate the three-dimensional motion and stress conditions of the suspended tunnel test mechanism under various test conditions, and truly and effectively and comprehensively reflect the dynamic response of the suspended tunnel under the action of wind, wave and ocean current loads; and the test device proposed by the present invention has a simple structure, low cost, scientific design, easy installation, accurate measurement and strong practicality.

The application discloses a kind of permanent magnet synchronous motor double vector model predicted current control methods considering dead zone, it is related to motor drive control technical field, comprising the following steps: S1, establish PMSM discrete prediction model and sampling: derivation current prediction equation;S2, based on the classification strategy of cost function and torque current: voltage vector is divided into overshoot vector group and under shock vector group;S3, double vector screening strategy based on classification strategy: screening out optimal double vector candidate combination;S4, dead zone determination and beatless time synthesis: output final switch control pulse.The application adopts the above-mentioned permanent magnet synchronous motor double vector model predicted current control method considering dead zone, reduces the current distortion caused by dead zone effect, solves the local optimal problem in traditional strategy, and greatly reduces the calculation burden, provides a kind of efficient control scheme with high dynamic response, global steady-state accuracy and low harmonic characteristic for ship PMSM propulsion system.