Single-phase grid-connected inverter with active power decoupling function and power decoupling method

Abstract

The invention relates to the technical field of miniature single-phase photovoltaic grid-connected inverters, and specifically discloses a single-phase grid-connected inverter with active power decoupling function and a power decoupling control method thereof. converter, a single-phase two-leg inverter circuit, an AC low-pass output filter circuit, and an active power decoupling circuit, the active power decoupling circuit is embedded in the single-phase two-leg inverter circuit to form a three-leg inverter circuit; the DC input source of the inverter is connected to the input terminal of the buck-boost converter, an input filter capacitor is connected in parallel therebetween, and the output terminal of the buck-boost converter is connected to the three-leg inverter circuit The input end of the three-bridge arm inverter circuit is connected to the input end of the AC low-pass output filter circuit; the power decoupling control is performed by using a pulse width energy modulation method. The present invention can use non-electrolytic capacitors as decoupling capacitors, avoiding the use of electrolytic capacitors, thereby prolonging the fault interval time of the inverter and improving the reliability of the system.

Description

technical field [0001] The invention relates to the technical field of miniature single-phase photovoltaic grid-connected inverters, in particular to a single-phase grid-connected inverter with an active power decoupling function and a power decoupling control method thereof. Background technique [0002] Residential power supply is mostly single-phase power, so the single-phase grid-connected inverter topology is widely used in household distributed power generation systems. However, while the single-phase grid-connected inverter meets the grid-connected requirements, it will cause power pulsation at twice the power frequency on the input side of the inverter. The low-frequency power ripple on the input side will seriously affect the energy utilization rate of the DC input source and increase the total harmonic distortion rate of the output grid-connected current. [0003] In the prior art, the method of passive power decoupling is usually used to solve this problem, that ...

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Problems solved by technology

[0006] The problem to be solved by the present invention is the defect of low reliability of the existing inverter power decoupling system. It provides a single-phase grid-connected inverter with active power decoupling function and a power decoupling control method, which can avoid Use electrolytic capacitors to extend the time between faults of the inverter and improve system reliability

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