Single-phase photovoltaic power generation dual-mode inverter system and control method thereof

Abstract

The invention provides a single-phase photovoltaic power generation dual-mode inverter system and a control method, and relates to the technical field of inverter control. The dual-mode inverter system is composed of a photovoltaic module, a Boost circuit, an LLC resonant converter, a bidirectional DC / DC converter, an inverter, a storage battery, a DC load, an AC load and a power grid. The loss ofthe inverter system can be reduced, the power generation efficiency of a photovoltaic inverter system is improved, and the dual-mode inverter meets the high-quality, high-reliability and high-stability power supply requirements of the power generation system through coordinated control over off-grid energy storage and grid-connected power generation. According to the invention, when a grid-disconnected mode is switched to a grid-connected mode, the output voltage of the inverter is controlled to continuously track the amplitude and the phase of a grid voltage; when the grid-connected mode isswitched to the grid-disconnected mode, the voltage reference value of the system is controlled to have the amplitude and phase of a load voltage before grid disconnection, thereby achieving the seamless switching, avoiding the impact of a large voltage and a large current, and guaranteeing the safety of the power grid and electric equipment.

Description

technical field [0001] The invention relates to the technical field of inverter control, in particular to a single-phase photovoltaic power generation dual-mode inverter system and a control method thereof. Background technique [0002] The supply of fossil fuels is facing a serious shortage crisis situation, and with the rapid growth of the world population and the continuous development of the economy, human beings' demand for energy is increasing, which will inevitably lead to an imbalance between energy supply and demand. In order to cope with the serious situation of the gradual shortage of fossil fuels, the energy consumption structure must be gradually changed, and it is imperative to vigorously promote new energy power generation. Distributed photovoltaic power generation system has gradually become the future development trend. [0003] Photovoltaic inverter is the most critical part of solar energy utilization. Its basic principle is to use the photovoltaic effect...

AI Technical Summary

Problems solved by technology

[0006] The present invention provides a single-phase photovoltaic power generation system in order to overcome the defect that the inverter system and power grid equipment are prone to large voltage and current impacts during the switching process of the above-mentioned existing photovoltaic power generation system. Dual-mode inverter system and control method thereof, the dual-mode inverter system composed of photovoltaic modules, Boost circuit, LLC resonant converter, bidirectional DC / DC converter, inverter, storage battery, DC load, AC load, and power grid The inverter system can reduce the loss of the inverter system and improve the power generation efficiency of the photovoltaic inverter system. The dual-mode inverter realizes the high quality and high reliability of the power generation system through the coordinated control of off-grid energy storage and grid-connected power generation. High stability and high power supply requirements, it can work in the state of off-grid independent power generation, and can also work in the state of grid-connected power generation

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