A delta-connected cascaded h-bridge inverter based on space vector modulation method

Abstract

The invention discloses a delta-connected cascaded H-bridge inverter based on a space vector modulation method. The three phases of the delta-connected cascaded H-bridge inverter are connected in a delta, and each phase is cascaded by 2n H-bridges; Each H-bridge includes 4 IGBTs; a delta-connected cascaded H-bridge inverter is controlled using a space vector modulation method; the space vector modulation method is based on a triangle locus model; a unique space vector modulation method is adopted, The delta-connected cascaded H-bridge inverter runs more stably and is easy to control.

Description

technical field The invention belongs to the field of delta-connected cascaded H-bridge multilevel inverters, and relates to a delta-connected cascaded H-bridge inverter based on a space vector modulation method. 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 cascaded modules need to withstand line voltage, and its short-circuit fault performance is better, suitable for high-voltage, large-capacity systems, typical applications such as hi...

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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 The vector modulation method is difficult to implement, and makes the inverter difficult to control and poor in stability

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