Inverter common-mode voltage suppression method based on logic switch vector optimization selection

Abstract

The invention discloses an inverter common-mode voltage suppression method based on logic switch vector optimization selection. The method comprises the following steps of detecting an actual output value [i alpha (k)] of an inverter at a tk moment; i Beta (k)]T, applying the optimal voltage vector Sx (k) of the last period to the inverter, x belongs to [a], b, c], prediction model, predicting Sx(k), x belongs to [a], determining a selectable vector range of the current value at the moment tk + 1 under the action of the (a, b, c) on the basis of an optimized vector range of a logic switch vector optimization method under a g-h coordinate system; under the g-h coordinate, calculating the coordinate; carrying out fCS-MPC prediction optimization on effective voltage vectors in a selectable vector range; selecting (k + 1) Ts; (k + 2) Ts], enabling the current at the moment tk + 2 to follow the vector Sx (k + 1) with the optimal performance index; wherein x belongs to [g, h], performing switching vector mapping switching mapping from a g-h coordinate system to an a-b-c coordinate system, and selecting a vector with the minimum common-mode voltage as a final optimal vector for next-period inverter control so as to realize minimum common-mode voltage output control of a redundant switching vector.

Description

technical field [0001] The invention relates to the technical field of predictive control of multilevel converters, in particular to an inverter common-mode voltage suppression method based on logic switch vector optimization selection. Background technique [0002] Energy shortage is one of the major problems facing the development of human society at present, and frequency conversion speed regulation is the most effective way to achieve energy saving and emission reduction. Thanks to the progress and development of power electronics technology, it has been widely used in high energy-consuming industrial fields High-power frequency conversion speed regulating device. However, in the operation of the inverter, the output side of the inverter will inevitably generate a large-scale common-mode voltage, which will bring many negative effects to the safe operation of electrical equipment such as motors, such as forming shaft currents on the motor shaft and destroying the motor i...

AI Technical Summary

Problems solved by technology

The method based on objective function optimization takes advantage of the characteristics of FCS-MPC to easily realize multi-objective optimal control. By adding the common-mode voltage suppression optimization performance index in the objective function, the control of the output common-mode voltage amplitude is realized, but the effect of common-mode voltage suppression is different from that of The selection of weight factors is closely related. Considering the conflict between optimization performance indicators, it is difficult to configure a single weight factor to meet the different control effects expected by the designer.

The core idea of ​​the method based on switch vector optimization is to eliminate the vector with large output common-mode voltage, and only select the vector with small output common-mode voltage, but for multi-level inverter and multi-objective comprehensive optimal control, Still have to solve the problem of excessive predictive computation and unweighted factor controller design

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