Miniature photovoltaic inverter based on primary side current feedback of flyback transformer

Abstract

The invention relates to a miniature photovoltaic inverter based on primary side current feedback of a flyback transformer. A decoupling capacitor Cpv is connected with a photovoltaic battery PV in parallel, one end of the photovoltaic battery PV is connected with one end of a primary side of the flyback transformer TR, the other end of the primary side of the flyback transformer TR is connected with a source of a pre-stage power switch tube Sm, a drain of the pre-stage power switch tube Sm is connected with the other end of the photovoltaic battery PV, a grid of the pre-stage power switch tube Sm is connected with a PWM (pulse width modulation) generator, the drain of the pre-stage power switch tube Sm is connected with a filter, the filter is connected with a current comparator, the output end of the current comparator is connected with the input end of a PI (power to loop) resonance controller, the output end of the PI resonance controller is connected with the PWM generator, one end of a secondary side of the transformer TR is connected with a positive electrode of an output diode D of the secondary side, and a negative electrode of the output diode D of the secondary side and the other end of the secondary side of the transformer TR are respectively connected with an output capacitor Co, a full-bridge inverting circuit and a filtering circuit. The miniature photovoltaic inverter has the advantages that the harmonics of grid-connected current flowing through zero point can be effectively eliminated, and the grid-connected efficiency and grid-connected quality of the inverter are improved.

Description

technical field [0001] The invention belongs to the field of new energy electronic control, in particular to a photovoltaic grid-connected inverter based on the primary side current feedback of a flyback transformer. Background technique [0002] Grid-connected current control technology mainly includes traditional control technology and control technology based on modern control theory. Among them, the traditional grid-connected current control technologies mainly include PI control, hysteresis control, repetitive control, predictive current control, and single-cycle control methods. The grid-connected current control technologies based on modern control theory mainly include fuzzy control, sliding mode variable structure control, adaptive control and so on. For the existing micro-inverter products, due to cost considerations, PI controllers with simple algorithm, low implementation cost and good stability are basically used, but there are two problems in PI control: it is...

AI Technical Summary

Problems solved by technology

[0004] In order to overcome the problems of low grid-connected efficiency and relatively large harmonics at the zero-crossing point when the input power is relatively low in the existing photovoltaic inverter single-mode mode, the present invention provides a method to effectively improve the grid-connected power of the inverter. Miniature photovoltaic inverter based on flyback transformer primary current feedback for efficiency and reduction of grid-connected current harmonics

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