Photovoltaic grid connection control method on basis of improved quasi-resonance control and repeated control

Abstract

The invention discloses a photovoltaic grid connection control method on the basis of improved quasi-resonance control and repeated control. The photovoltaic grid connection control method includes steps of utilizing the difference between given grid connection current and actual output grid connection current of an inverter as input of a quasi-resonance controller and a repetition controller, utilizing the difference between the given zero direct current and the actual output grid connection current as input of an integral controller, adding the output of the quasi-resonance controller and the repetition controller as control signals of connection and disconnection of an inverter bridge switching tube in an inversion link. The photovoltaic grid connection control method combines the advantages of resonance control, repeated control and integral control, affection generated by grid voltage and frequency fluctuation can be effectively reduced, good dynamic and steady tracking performance is achieved, and optimal design of the grid connection control is benefited.

Description

technical field [0001] The invention relates to the technical field of new energy power generation, in particular to a photovoltaic grid-connected hybrid control method based on improved quasi-resonant control (QPRI) plus repetitive control (RC). Background technique [0002] With the growth of photovoltaic power generation installed capacity, the industry has put forward higher and higher requirements for the grid-connected power quality of solar photovoltaic power generation. Research on high-performance and high-efficiency photovoltaic grid-connected inverters is of great significance to the development of photovoltaic power generation industry. [0003] At present, the grid-connected current control methods of single-phase photovoltaic grid-connected inverters that are widely used in engineering mainly include proportional integral (PI) control, deadbeat control, repetitive control and proportional resonance control. Proportional-integral (PI) control is the most widely ...

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Problems solved by technology

Research on Control Strategy of Grid-connected Inverter in Photovoltaic Power Generation System (Chen Ruirui, Chen Huiming, Wang Zhengshi. Research on Control Strategy of Grid-connected Inverter in Photovoltaic Power Generation System[J]. Mechanical and Electrical Engineering, 2013,30(5):619-622) Proposed a Based on the improved algorithm of DSP digital control segmental PI+quasi-proportional resonant controller, this algorithm can reduce the harmonics of grid-connected current and reduce the interference of grid voltage fluctuations to the system, but its harmonic suppression ability is not strong enough

Harmonics Suppression for Single-Phase Grid-Connected PV Systems in Different Operation Modes (Yongheng Yang, Keliang Zhou, Frede Blaabjerg."Harmonics Suppression for Single-Phase Grid-Connected PV Systems in Different Operation Modes,"2013Twenty-Eighth Annual IEEE Applied Power Electronics Conference Exposition (APEC), 2013, pp, 889-896.) proposed a hybrid control strategy based on resonance and repetition, which uses resonance control to achieve no static error tracking of command signals, while repetitive control is used to remove harmonic interference. This algorithm can efficiently filter out high-order harmonic interference, but the interference suppression ability for low-order harmonics such as 3th, 5th, and 7th is not strong

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