The invention provides a method for controlling model prediction current of a low-loss voltage source inverter. The method comprises the steps of: sampling load current of the inverter at k time and converting the load current into a current component in an alpha beta coordinate system by clake; acquiring 8 voltage vectors according to a switch status of the inverter; converting the voltage vectors corresponding to different switch statuses into the voltage components in the alpha beta coordinate system; predicting a current value at k+1 time according to the current component and the voltagecomponents; putting the current value into a first target function to calculate; combining each one zero vector with each one nonzero vector randomly from 8 voltage vectors; calculating the action time of each voltage vector combination; calculating a second target function to determine two groups of optimal combinations; and selecting one voltage vector combination to act on the inverter according to the three-phase load current. By adoption of the method provided by the invention, two vectors are used in each control period, so as to reduce the harmonic wave of the current; and, the method can be applied to the high-power photovoltaic grid-connected inverter or the motor drive controller, so as to reduce the system loss.

Method for controlling model prediction current of low-loss voltage source inverter

The invention relates to a photovoltaic grid-connected inverter dynamic performance optimization method based on MPDPC, and the method comprises the following steps: S1, detecting three-phase grid voltage, three-phase grid current and direct current bus voltage of a three-phase voltage type photovoltaic grid-connected inverter system of the current moment k, and performing calculation to predict active power and reactive power of a moment k+1; S2, according to the active power and the reactive power of the moment k+1, predicting backwards one beat and acquiring the active power and the reactive power of a moment k+2; S3, substituting the active power and the reactive power of the moment k+2 into an improved index function, performing amplitude limiting for a power difference value, therebyselecting an optimal nonzero vector; S4, acquiring duty ratio of the time when the optimal nonzero vector and a zero vector act in combination, and through modulating the duty ratio, obtaining a switching signal for controlling power devices. Compared with the existing technology, the method provided by the invention can restrain coupling between active and reactive of a grid-connected system, moreover, system dynamic response performance is improved remarkably while power control steady-state performance of the conventional MPDPC method is kept.

Photovoltaic grid-connected inverter dynamic performance optimization method based on MPDPC

The invention provides a Nanofoil-based miniature quick connector. The Nanofoil-based miniature quick connector comprises a first base layer and a second base layer below the first base layer; the first base layer and the second base layer are fixedly connected; a first copper wiring layer is arranged on the upper surface of the first base layer; a second copper wiring layer is arranged on the upper surface of the second base layer; a third copper wiring layer is arranged on the lower surface of the second base layer; a cavity is formed in the middle of the first base layer; the cavity is located below the first copper wiring layer; an insulating layer is arranged in the cavity; a Nanofoil nano alloy foil sheet is arranged in the middle of the insulating layer; the Nanofoil nano alloy foilsheet is fixedly connected with the third copper wiring layer through a probe; and a through hole for allowing the probe to penetrate through is formed in the second copper wiring layer. The miniature quick connector is simple in structure, low in cost and high in controllability, can be replaced and integrated easily, and has the function of an industrial fast connector; meanwhile, the problem that an industrial connector cannot be integrated is also solved; and the miniature quick connector has high working characteristics for fault branch bypass circuits and switching in actual operation of the electrical equipment.

Nanofoil-based miniature quick connector

The embodiment of the application discloses a modular multi-level converter control method, device and apparatus. The method includes: collecting voltage signals and current signals of a transformer network side and performing coordinate transformation. The instantaneous real power and the instantaneous imaginary power are calculated by the formula of instantaneous power. The power reference valueof the converter is obtained, and the difference between the power reference value and the instantaneous power obtained before is calculated, and the PI control is carried out to obtain the power compensation value; and then the compensation voltage value is calculataed by the compensation voltage calculation formula; at last, the compensate voltage is fed forward to obtain the voltage expectation value, and the voltage expectation value is inversely converted and output, so that the power oscillation can be restrained, the stability of the HVDC transmission system can be improved, and the technical problem that the power oscillation may be deteriorated by the classical decoupling control in the prior art can be solved.

Modular multi-level converter control method, device and apparatus

The invention provides a three-phase PWM rectifier fault-tolerant operation method based on simplified model predictive control, which relates to the technical field of high-power power electronics. Athree-phase simplified model prediction control strategy and a single-phase simplified model prediction control strategy are respectively adopted under a normal working condition and a fault condition; by simplifying an iterative optimization mode of a traditional model prediction algorithm, original eight-time optimization and four-time optimization are reduced to one-time optimization, the calculation burden of a processor is greatly reduced, the simplicity of the algorithm is improved, the reliability and stability of a control system are enhanced, and the method is suitable for high-frequency development of a PWM rectifier in the future. Due to high dynamic response of simplified model prediction control, grid-side current can quickly track a reference value without overshoot, a short-circuit circuit can be set according to the maximum load current, the protection sensitivity is greatly improved, and the method has practical significance.

Three-phase PWM rectifier fault-tolerant operation method based on simplified model predictive control

The invention discloses a fault-tolerant voltage-sharing control method for a bidirectional AC/DC energy storage converter. The fault-tolerant voltage-sharing control method comprises the steps of: step S1, constructing a switching state Si; S2, acquiring an expression of output voltage Uj and the switching state Si; S3, constructing a power secondary prediction model; S4, calculating a predicted value of DC side discrete capacitor voltage difference; S5, constructing a value function g; S6, carrying out initialization; S7, acquiring voltage and output current of a power grid; S8, calculating output voltage Uj in the current switching state; S9, calculating a first power predicted value; S10, calculating a power predicted value; S11, calculating the value function g; S12, comparing magnitude of the value function g with a comparison variable m, and assigning a minimum value to the comparison variable m; S13, and carrying out judgment and outputting a result. The fault-tolerant voltage-sharing control method conducts two-step prediction on the output power, calculates the optimal voltage vector ahead, compensates for algorithm delay effectively, and reduces the influence of the delay on system performance. When the sampling efficiency is high after the delay compensation is added, the fault-tolerant voltage-sharing control method can significantly reduce power fluctuations and decrease grid-connected current harmonic distortion.

Fault-tolerant voltage-sharing control method for bidirectional AC/DC energy storage converter

The invention discloses a prediction and control method of a bidirectional AC/DC converter fault tolerance model under imbalance of a power grid. The method comprises the following steps: step S1, structuring a switch state Si; S2, acquiring an expression of an output voltage vector Uj and the switch state Si; S3, structuring a power prediction model; S4, calculating a compensation value pcom of active power and a compensation value qcom of reactive power; S5, structuring an evaluation function g; S6, initializing; S7, collecting a variable value; S8, calculating output voltage Uj under the current switch state; S9, calculating a power predicted value; S10, calculating the compensation value pcom of the active power and the compensation value qcom of the reactive power; S11, calculating a value function g; S12, comparing the value function g and a comparative variable m, and giving a minimum value to the comparative variable m; and S13, judging and outputting. An optimum switch drive control signal is directly outputted, the positive-sequence and negative-sequence current separation control and PWM modulation signal are not needed, easiness in implementation is realized, the power connection current harmonic content can be reduced, the pulse of active power is eliminated, and the power connected electric energy quality can be improved.

Prediction and control method of bidirectional AC/DC converter fault tolerance model under imbalance of power grid

The invention discloses a method for controlling the direct power of an open-winding brushless doubly-fed generator. The method comprises the following steps: establishing a mathematical model for controlling the direct power of the open-winding brushless doubly-fed generator; designing an improved super-distortion sliding mode controller, establishing an open-winding brushless doubly-fed generator direct power control mathematical model based on an improved super-distortion sliding mode, carrying out stability analysis based on a Lyapunov function, and obtaining the range of control model parameters; randomly selecting a combination of a group of parameters within the range of control model parameters for simulation verification; if the control precision meets the direct power control requirement, ending the design; otherwise, correcting the control model parameters again until the control precision meets the design requirement, substituting the control model parameters meeting the direct power control requirement into the open-winding brushless doubly-fed generator direct power control mathematical model based on the improved super-twisting sliding mode, and obtaining an accuratecontrol model. The method is high in control precision, high in response speed and good in dynamic and static performance and robustness.

Method for controlling direct power of open-winding brushless doubly-fed generator

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Fault-tolerant voltage-sharing control method for bidirectional AC/DC energy storage converter

Prediction and control method of bidirectional AC/DC converter fault tolerance model under imbalance of power grid

Method for controlling direct power of open-winding brushless doubly-fed generator