Multilevel circuit and isolated power circuit thereof

Abstract

The invention discloses a multilevel circuit and an isolated power circuit thereof, in order to reduce common mode interference. The isolated power circuit comprises a plurality of isolated power supplies, the power supplies are used for supplying power for isolated driving chips, wherein the isolated driving chips corresponding to switching tubes not common-ground in the multilevel circuit are powered by different isolated power supplies; secondary sides of the isolated power supplies are in common-ground with the switching tubes driven by the isolated driving chips respectively powered by the isolated power supplies; the plurality of isolated power supplies are respectively numbered as 1, 2, 3, ..., m-1 and m isolated power supplies, m refers to the total number of the plurality of isolated power supplies, then the primary side of the first isolated power supply is in common-ground with an auxiliary power supply, or a ground end of the primary side of the first isolated power supply is suspended; and the ground end of the secondary side of the first isolated power supply is connected with the midpoint of a DC bus; the primary side of the first isolated power supply is in common-ground with the secondary side of an arbitrary isolated power supply in the previous (i-1) isolated power supplies, wherein i = 1, 2, 3, ..., m-1 and m.

Description

technical field [0001] The present invention relates to the technical field of power electronics, and more particularly, to a multilevel circuit and an isolated power supply circuit thereof. Background technique [0002] A multi-level circuit generally refers to a circuit whose output has multiple levels. For example, a capacitor-clamped five-level circuit is a typical multi-level circuit. [0003] Since there are switches that do not share the same ground in the multi-level circuit, the driving mode of the switches in the multi-level circuit adopts the isolation drive. Specifically, each switch in the multi-level circuit has an independent isolation driver chip. The isolated driver chips corresponding to the switches that do not share the ground are powered by different isolated power sources, and the isolated driver chips corresponding to the switches that share the same ground can be powered by different isolated power sources, or can be powered by the same isolated power...

AI Technical Summary

Problems solved by technology

[0004] However, with the turn-on and turn-off of each switch tube in the multi-level circuit, there is a common-mode voltage with a peak value equal to the DC bus voltage between the ground of the primary side and the ground of the secondary side of the isolated power supply, which will cause serious common-mode voltage interference

Images