Control system and method for photovoltaic medium-voltage distributed control system

Abstract

The embodiment of the invention provides a control system and method for a photovoltaic medium-voltage distributed control system. The photovoltaic medium-voltage distributed control system comprisesN photovoltaic modules, N direct current-direct current converters, a direct current-alternating current converter and an industrial frequency transformer, wherein output ends of the N direct current-direct current converters are connected to a direct current bus in parallel; the direct current bus is connected with the direct current-alternating current converter; and the industrial frequency transformer is used for being connected with a medium-voltage alternating-current power grid. The control system comprises a bus voltage sampling circuit and N direct current-direct current converter control circuits in one-to-one correspondence with the N direct current-direct current converters, wherein each direct current-direct current 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 generation circuit. The direct-current bus voltage is used for replacing a signal line for communication, a communication system can be greatly simplified, and reliability of the control system is improved.

Description

Technical field [0001] The invention relates to the technical field of photovoltaic power supply control, and more specifically to a control system and method for a photovoltaic medium-voltage collecting and distributing 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 studied and applied due to their abundant resources, clean and environmental protection and many other advantages. [0003] Facing the application requirements of large-scale photovoltaic power plants, medium-voltage-based photovoltaic power generation systems have higher efficiency and lower cost than traditional low-voltage systems. The photovoltaic medium-voltage distribution system mostly adopts a string structure, which is composed 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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