Photovoltaic grid-connected inverter control method with multi-resonance PR and PI joint control

Abstract

The invention discloses a photovoltaic grid-connected inverter control method with multi-resonance PR and PI joint control. The method comprises the steps of (S01) adding a higher harmonic compensation link in a quasi-PR controller to form a multi-resonance PR controller, (S02) taking a difference between a given grid-connected current Iref and an actual grid-connected current IL as an input of the multi-resonant PR controller, (S03) taking a difference between a grid-connected current direct-current reference value IL-dc and a grid-connected current DC amount as an input of a PI controller, (S04) adding an output of the multi-resonant PR controller and an output of the PI controller to be a control signal for turning on and off an inverter switch tube, and (S05) obtaining an equivalent proportional gain kIL of an average value of the actual grid-connected current IL to the actual grid-connected current IL. The invention provides the photovoltaic grid-connected inverter control methodwith multi-resonance PR and PI joint control, the influence of grid voltage harmonics and distortion on the grid-connected current is suppressed, the DC component of the grid-connected current is alsoeliminated, and the high-quality control of a non-isolated photovoltaic grid-connected inverter is achieved.

Description

technical field [0001] The invention relates to a control method for a photovoltaic grid-connected inverter controlled by multi-resonant PR and PI joint control, and belongs to the technical field of new energy photovoltaic power generation. Background technique [0002] With the increasingly serious problems of traditional fossil energy crisis and environmental pollution, photovoltaic power generation technology with energy saving and environmental protection features has attracted great attention worldwide. The grid-connected inverter is an important part of the photovoltaic power generation system, and its control technology is the key to obtaining high-quality grid-connected electric energy. At present, the control technologies of photovoltaic grid-connected inverters include: repetitive control, hysteresis control, deadbeat control, PI control, predictive current control and PR control. Although the above control techniques can meet the control requirements to a certai...

AI Technical Summary

Problems solved by technology

Although the above control technologies can meet the control requirements to a certain extent, they all have shortcomings.

The dynamic performance of the traditional single repetitive control is poor; the hysteresis control will make the switching frequency not fixed, resulting in unnecessary loss; the dead beat control has a strong dependence on the parameters; the PI control cannot realize the static difference control for the AC control signal, Lack of sufficient suppression ability for various high-order current harmonics; predictive current control is always one-beat control due to sampling and calculation delay; although PR control can achieve no-static control of AC signals, it cannot eliminate DC components

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