A three-phase h-bridge zero-sequence component suppression system and suppression method

Abstract

A three-phase H-bridge zero-sequence component suppression system and suppression method. The system includes a DC bus support module located at the input end of the system and providing a bus support voltage to the DC side. The output end of the DC bus support module is connected to convert direct current into alternating current. The three-phase H-bridge DC / AC conversion module, the output end of the three-phase H-bridge DC / AC conversion module is connected to a three-phase filter module for filtering the AC output of the converter, the output end of the three-phase filter module is connected to the transformer module, The transformer module boosts the output voltage of the converter and merges it into the power grid; adopts the "virtual delta connection" three-phase H-bridge PWM modulation mode, through the control of the switching tubes in each bridge arm of the three-phase H-bridge, that is, X, Phase B shares one modulating wave, phase Y and C share one modulating wave, and phase Z and A share one modulating wave, so that the six bridge arms of the three-phase H bridge form a "△" connection, which makes the zero-sequence current form The circulating current cannot flow out, thus effectively suppressing the generation of zero-sequence components.

Description

technical field [0001] The invention relates to the technical field of three-phase H-bridge zero-sequence component suppression, in particular to a three-phase H-bridge zero-sequence component suppression system and suppression method. Background technique [0002] Three-phase H-bridge topology such as Figure 1a and Figure 1b As shown, the topology is a three-phase converter composed of three single-phase H-bridges, which has high output power density and is easy to realize multi-level modulation, so this topology is commonly used in multi-level converters. Since there is no power coupling between the three-phase output currents of this topology, the two bridge arms of each phase H-bridge form a current loop with each other, so the rear stage of the topology converter needs a three-phase six-tap transformer to be connected to it. Currently, there are two types of transformers used in the prior art: [0003] 1. The transformer adopts a three-phase transformer group compos...

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Problems solved by technology

[0006] In order to overcome the problem of poor separation effect in the above-mentioned prior art, the object of the present invention is to provide a three-phase H-bridge zero-sequence component suppression system and suppression method, which effectively suppresses the PWM zero-sequence component of the three-phase H-bridge without Easy to implement with hardware changes; significantly reduces transformer cost

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