A double-buck full-bridge grid-connected inverter based on frequency multiplication modulation

Abstract

The invention discloses a dual buck full-bridge grid-connected inverter based on frequency multiplication modulation, the dual buck full-bridge grid-connected inverter comprises a power switch tube S5, wherein a drain of the power switch tube S5 is connected with a positive electrode of direct current voltage Udc, and a source of the S5 is respectively connected with the drain of a power switch tube S1, a negative electrode of a diode D2, the drain of a power switch tube S3 and the negative electrode of a diode D4. For the inverter provided by the invention, frequency multiplication modulationis used on the aspect of control, under the premise of constant switching frequency, working frequency is improved to double of the original frequency, thus, higher output voltage frequency can be obtained and grid-connected electrical energy quality is improved; isolation between an alternating current side and a direct current side is realized structurally, and direct current component of the grid-connected voltage is reduced; moreover, the switch tube is in a half-cycle working mode, thus, switch loss is reduced, continuing current circuit grid-connected current does not pass through a body diode which has relatively poor performance, so, the dual buck full-bridge grid-connected inverter has the advantages of low grid current total harmonic distortion and high reliability.

Description

technical field [0001] The invention relates to the field of photovoltaic grid-connected inverters, in particular to a double-buck full-bridge grid-connected inverter based on frequency multiplication modulation. Background technique [0002] Although the existing double Buck full-bridge grid-connected inverter has the advantages of high DC voltage utilization rate, no common-mode leakage current, three-level output, and low loss, there are two DC inductors in the circuit, which are large in size and difficult to operate. At this time, only one inductor is always in the working state, resulting in low utilization of magnetic components, high system cost, and low power density; in addition, the decoupling between the DC side and the AC side of the inverter is not realized, which makes the DC component of the grid-connected current The content is higher. If the bipolar frequency multiplication modulation strategy is adopted, the equivalent operating frequency of the grid-conn...

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Problems solved by technology

[0003] Aiming at the above-mentioned deficiencies in the prior art, the present invention provides a double-buck full-bridge grid-connected inverter based on frequency multiplication modulation, which solves the problem of large current harmonic content and leakage current of the existing double-buck grid-connected inverter. The problem of large volume and high cost of large and filter inductors

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