Miniature grid-connected inverter and control method thereof

Abstract

The invention discloses a miniature grid-connected inverter and a control method thereof. The inverter comprises a power decoupling module, an interleaved flyback module, a full bridge inversion module and an LC filter module which are sequentially connected between a photovoltaic panel and a public power grid, wherein the power decoupling module, the interleaved flyback module, the full bridge inversion module and the LC filter module are respectively connected with a control unit, the interleaved flyback module comprises two flyback circuits with load balancing and active clamping functions, the two circuits are identical in structure and parameter, and the two circuits mutually alternate 180 degrees to work in one switch cycle. The miniature grid-connected inverter has the advantages that the two interleaved flyback circuits simultaneously alternately work, transformer size can be reduced effectively, power density can be increased, component number is reduced effectively, output current ripples are reduced, coupling capacitor size is reduced, cost is reduced, and the miniature grid-connected inverter is suitable for being used and popularized.

Description

technical field [0001] This application relates to a miniature photovoltaic grid-connected inverter and a control method, which can convert the DC power from the photovoltaic panel into AC power with the same frequency and phase as the public AC power grid and inject it into the public power grid to realize the utilization and conversion of recyclable clean energy . Background technique [0002] At present, the topological structures of micro photovoltaic grid-connected inverters are mainly forward and flyback structures, and the forward structure requires a decoupling transformer, which has many components and high cost, and is not suitable for low-power use and popularization; flyback Due to the existence of leakage inductance on the primary side of the structure, when each switching cycle is turned off, the high-voltage pulse spikes generated by the leakage inductance on the primary side are likely to cause damage to components. The traditional RCD (Resistance Capacitance...

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Problems solved by technology

In solution (2), there is no clamping circuit designed for the leakage inductance in the flyback, and the leakage inductance is likely to cause device damage and reduce system efficiency

In addition, schemes (1) and (2) both adopt a staggered parallel structure, but there is no function of balancing and regulating the load power of the two flyback structures. It is easy to cause unbalanced loads of the two circuits due to physical reasons or interference. Excessive power load can damage components or cause temperature rise, resulting in system instability

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