Control system and method for photovoltaic medium voltage distribution system

Abstract

Embodiments of the present invention provide a control system and method for a photovoltaic medium-voltage distribution system. The photovoltaic medium-voltage distribution system includes N photovoltaic modules, N DC-DC converters, DC-AC converters, and power frequency transformers. Among them, the output ends of the N DC-DC converters are connected to the DC bus in parallel, and the DC bus and DC-AC converter connection, the power frequency transformer is used to connect with the medium-voltage AC power grid, wherein the control system includes a bus voltage sampling circuit and N DC-DC converter control circuits corresponding to N DC-DC converters one-to-one , wherein each DC-DC converter control circuit includes a bus voltage sampling circuit, a photovoltaic sampling circuit, a droop controller, a maximum power point tracking controller, an input voltage loop regulator and a pulse width modulation wave generating circuit. Using the DC bus voltage to replace the signal line for communication can greatly simplify the communication system and improve the reliability of the control system.

Description

technical field [0001] The invention relates to the technical field of photovoltaic power supply control, and more specifically relates to a control system and method for a photovoltaic medium-voltage distribution system. Background technique [0002] With the increasingly prominent problems of energy shortage and environmental pollution, renewable energy sources such as solar energy and wind energy have been widely researched and applied due to their rich resources, clean and environmental protection, and many other advantages. [0003] Facing the application requirements of large-scale photovoltaic power plants, photovoltaic power generation systems based on medium voltage have higher efficiency and lower cost than traditional low-voltage systems. The photovoltaic medium-voltage distribution system mostly adopts a string structure, which consists of multiple distributed DC-DC converters (DC / DC converters) and a large-capacity centralized DC-AC converter (DC / AC converter). ...

AI Technical Summary

Problems solved by technology

However, considering the large number of photovoltaic arrays and wide geographical distribution of large-scale photovoltaic power plants, fast real-time communication between DC-DC converters and DC-AC converters is difficult to achieve.

It can be seen that the traditional control method based on signal line communication is difficult to apply to the wide-area distributed photovoltaic medium voltage distribution system

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