Adaptive nonlinear control method for megawatt medium voltage medium frequency three-level DC converter

Abstract

The invention relates to a control method of a power electronic power conversion device, in particular to an adaptive nonlinear control method suitable for a megawatt-level medium-voltage medium-frequency three-level DC converter. The control scheme mentioned in the present invention mainly completes the voltage stabilizing output function and the short-circuit current limiting control function, so as to realize the ability to adapt to the change and disturbance of the subsequent stage load and the short-circuit fault protection ability. The controller mentioned in the present invention divides the system state into CCM steady state, DCM steady state and dynamic state, and the switching between the three states is accompanied by parameter adaptive adjustment, so as to obtain relatively good dynamic and static characteristics of voltage stabilized output. The controller mentioned in the present invention can overcome the shortcomings of the traditional control method that it is difficult to take into account the dynamic performance and static performance of the voltage stabilized output, as well as the shortcomings of different working modes, and can obtain the smaller ripple in the steady state and the smaller voltage fluctuation in the disturbance to the maximum extent. Advantages of small size and faster recovery time.

Description

technical field [0001] The invention relates to a control method of a power electronic power conversion device, in particular to an adaptive nonlinear control method suitable for a megawatt-level medium-voltage medium-frequency three-level DC converter. Background technique [0002] The megawatt-level medium-voltage medium-frequency three-level DC converter can convert medium-high voltage direct current into low-voltage direct current, and realize the electrical isolation between the medium-high voltage direct current grid and the low-voltage direct current grid. With the wide application of direct current in land power systems and independent power systems such as locomotives, ships, and islands, megawatt-level medium-voltage intermediate-frequency three-level DC converters have broad market prospects. Its research results can also be extended and applied to distributed power generation in power systems, smart grids, clean energy and other occasions, with potentially huge s...

AI Technical Summary

Problems solved by technology

[0011] Therefore, it is difficult for the traditional PI control scheme to adjust a set of fixed controller parameters to meet the steady-state and dynamic performance of the system under different load levels. If a compromise is made, a part of the controller performance must be sacrificed, which is obviously not what is expected.

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