A Space Vector Modulation Method for Delta-connected Cascaded H-Bridge Inverters

Abstract

The invention discloses a space vector modulation method for delta-connected cascaded H-bridge inverters. As the space vector modulation algorithm increases with the increase of cascaded units, the basic vectors increase greatly, and there are a large number of redundant switch state vectors. The switch state vectors The selection and the calculation of the action time are extremely complicated. The present invention is based on the α'‑β' coordinates, and utilizes the abscissa, ordinate, and the sum of the abscissa and ordinate of the basic vectors of the cascaded multilevel inverters in star form Corresponding to the three line voltage vectors of the three-phase inverter, and the relationship between the phase voltage and the line voltage of the star-connected three-phase inverter, the basic vector of the synthesized phase voltage reference vector in the star connection mode is directly used as the delta connection This method does not need to calculate the switch state signals corresponding to the basic vectors of each phase, and does not need to calculate a large number of redundant switch state vectors, which greatly simplifies the space vector modulation method of cascaded multi-level inverters.

Description

technical field The invention belongs to the field of space vector modulation method of delta-connected cascaded H-bridge multi-level inverters, and relates to a space vector modulation method of delta-connected cascaded H-bridge inverters, in particular to a method in α′-β′ A Fast Space Vector Modulation Method for Delta-Connected Cascaded H-Bridge Multilevel Inverters Under Coordinates. Background technique The cascaded multi-level inverter technology is widely used in high-voltage and high-power converters. Its advantage is that it can use the cascade connection of power units to realize voltage division and effectively expand capacity. High-voltage and high-power H-bridge cascaded multi-level inverters have two wiring modes: star and delta. The cascaded modules in the star-connection mode bear the phase voltage, so the cost can be reduced under low voltage conditions, but its reliability is not good. High, difficult to control under fault conditions; delta connection ca...

AI Technical Summary

Problems solved by technology

However, with the increase of the cascaded units in the space vector modulation method, the number of basic vectors increases greatly, and corresponding to one basic vector, there are multiple redundant switch state vectors. The selection of switch state vectors and the calculation of their action time are extremely complicated, resulting in Vector modulation method is difficult to implement

Images