Enhanced bidirectional Z-source inverter

Abstract

In order to solve the defect that a conventional Z-source inverter has limited boosting capability, an abnormal working state and energy that cannot flow in two directions, the present invention proposes an enhanced bidirectional Z-source inverter. The enhanced bidirectional Z-source inverter comprises a three-phase inverter formed by a DC voltage source and a three-phase inverter bridge and a Z-source network formed by a fully-controlled switching tube, a switching inductor and a capacitor, the enhanced bidirectional Z-source inverter is characterized in that a single inductor is substitutedby a switch inductor branch, a head end of the Z-source network is connected to a power supply, and a tail end of the Z-source network is connected to a three-phase inverter bridge. Compared with thetraditional Z-source inverter, the enhanced bidirectional Z-source inverter has the advantages that the boosting capability of the inverter can be improved, a high gain factor is achieved, the outputquality of the whole inverter is improved, the voltage stress of the Z-network capacitor is effectively reduced, the abnormal working state is eliminated, the starting surge current is reduced, at thesame time, a diode that blocks energy feedback is replaced by the fully-controlled switching tube, and the enhanced bidirectional Z-source inverter has the ability to flow in two directions.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to an enhanced bidirectional Z-source inverter. Background technique [0002] Microgrid technology is the key to the development and utilization of renewable energy such as wind energy and solar energy. The inverter is the core interface component of the micro-grid, it is the guarantee for the efficient operation of the micro-grid, and it is the medium of energy exchange between the distributed energy source and the grid; For grid-connected power generation, it is necessary to add a DC-DC step-up link to form a two-stage grid-connected power generation system, which has a complex structure and difficult control. [0003] The Z-source inverter uses the straight-through state to achieve a single-stage boost, which is suitable for a single-stage grid-connected power generation system, but there are problems such as large start-up surge current, low boost gain, and bidirectio...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the deficiencies in the above-mentioned prior art, the present invention provides an enhanced bidirectional Z-source inverter, which can improve the boosting capability of a single-stage inverter, realize high-gain boosting, and improve the output quality of the entire inverter; Effectively reduce the voltage stress of the Z network capacitor, thereby reducing the volume and weight of the inverter; eliminate abnormal working conditions; solve the problem of excessive starting current; at the same time, use a full-control switch tube to replace the diode that hinders energy feedback, so that it has energy Two-way flow capability

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