The on-grid photovoltaic power generation system, as the name suggests, converts the direct current generated by photovoltaic cells into alternating current through grid connection to meet the demands of the power grid. This process mainly relies on the operation of the grid-connected inverter. The grid-connected inverter is a device that can convert direct current to alternating current, with its core component being the power electronic converter. The power electronic converter is mainly composed of semiconductor switching devices. By controlling the on and off of the switching devices, it converts direct current to alternating current.
The on-grid photovoltaic power generation system mainly consists of distributed power sources, loads, energy storage systems, and control devices. Among them, the distributed power source is the core of the system, including photovoltaic grid-connected inverters, wind power grid-connected inverters, etc. The photovoltaic grid-connected inverter converts the direct current generated by the solar panels into alternating current, while the wind power grid-connected inverter converts the energy generated by the wind turbine. Additionally, the on-grid solar PV system also includes energy storage systems, such as batteries, to store energy for load use.
The on-grid solar PV system has multiple functions. First, it can operate in conjunction with the external power grid while accepting grid dispatching. Second, when the external grid fails or requires independent operation, the system can independently complete power generation and supply tasks. Moreover, the on-grid solar PV system also has self-control, protection, and management functions to ensure the stable operation of the system.
When sunlight is strong, the on-grid solar PV system can supply power to AC loads while delivering excess electricity to the grid. When sunlight is insufficient, meaning the solar array cannot provide enough power for the load, the system can draw power from the grid to supply the load. Compared to standalone photovoltaic power generation systems, grid-connected photovoltaic power generation systems do not need to be equipped with energy storage devices (such as batteries), which can reduce system costs, eliminate the trouble of maintaining and replacing batteries, and increase power supply reliability. When designing the tilt angle of the solar cell array, one can choose the angle that corresponds to the maximum solar radiation received throughout the year to maximize the power generation capability of the solar cell array. During peak electricity consumption periods such as summer, when solar radiation intensity is high, the on-grid solar PV system generates relatively more electricity, which can help the power grid to peak shave.
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