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 particularly discloses a single-phase grid-connected inverter with an active power decoupling function, and a power decoupling control method of the single-phase grid-connected inverter. The inverter comprises a buck-boost converter, a single-phase two-bridge-arm inversion circuit, an alternating-current low-pass output filter circuit and an active power decoupling circuit, wherein the active power decoupling circuit is embedded into the single-phase two-bridge-arm inversion circuit to form a three-bridge-arm inversion circuit; a direct-current input source of the inverter is connected with an input end of the buck-boost converter; an input filter capacitor is connected in parallel between the direct-current input source of the inverter and the input end of the buck-boost converter; an output end of the buck-boost converter is connected with an input end of the three-bridge-arm inversion circuit; an output end of the three-bridge-arm inversion circuit is connected with an input end of the alternating-current low-pass output filter circuit; and power decoupling control is performed by a pulse width energy modulation method. The inverter can use a non-electrolytic capacitor as a decoupling capacitor and avoids an electrolytic capacitor, so that the fault interval time of the inverter is prolonged, and the reliability of a system is improved.

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 ...

AI Technical Summary

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

Images