Variable frequency type three-phase photovoltaic inverter system and control method thereof

Abstract

The invention relates to a photovoltaic inverter system and a control method thereof, in particular to a variable frequency type three-phase photovoltaic inverter system and a control method thereof. The variable frequency type three-phase photovoltaic inverter system comprises a master control part, an inverter circuit, a detection circuit, a storage battery charging and discharging circuit, a storage battery interface, a photovoltaic assembly interface, a power frequency load interface, a variable frequency load interface, an electronic control switch, a warning answering device, and an optional isolation transformer. The control method comprises the following steps: when the variable frequency load requests to supply power, on the premise that all power frequency loads are allowed to be powered off, all power frequency loads are disconnected and forbidden to be switched on, and the variable frequency load is powered on in a variable frequency mode; when the frequency is changed into a constant power frequency, a system automatically electrifies the power frequency loads which are allowed to be electrified one by one by referring to the important grade set in advance by a user, wherein the power sum of the power frequency loads is not more than the residual power generation capacity of the system. For the photovoltaic power generation system with the motor type load, the amount of the photovoltaic assembly can be reduced at the beginning of the scheme design by the invention, and the installation cost is lowered.

Description

technical field [0001] The invention relates to a photovoltaic inverter system and a control method thereof, in particular to a frequency-variable three-phase photovoltaic inverter system and a control method thereof. Background technique [0002] With the development of modern industry, non-renewable energy sources such as oil, coal, and natural gas are becoming increasingly rare. The new energy represented by solar energy conforms to the trend of the global low-carbon economy, and has been recognized, valued and supported by governments around the world. [0003] Photovoltaic power generation-related industries have developed rapidly in recent years, but today, compared with traditional power generation systems that use non-renewable energy such as coal and oil, photovoltaic power generation is still at a disadvantage in terms of cost. This requires scientific and technological workers to continuously explore, on the one hand, to improve the conversion efficiency of the ph...

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Problems solved by technology

[0004] Nowadays, there are quite a few motor loads among the electric loads. This type of load requires a large power supply in a short period of time when it is started. The photovoltaic power generation system not only provides active power, but also must provide a certain amount of reactive power at the same time. , the power consumption is greatly increased compared with the stable operation. Therefore, at the beginning of the design of the photovoltaic power generation system, the designer usually designs the capacity of the photovoltaic module to be a wattage that is half to several times higher than the rated power of the load. Undoubtedly, this Significantly increased the installation cost of photovoltaic power generation systems based on photovoltaic modules

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