Photovoltaic reverse-power closed loop control system and method

Abstract

The invention relates to a photovoltaic reverse-power closed loop control system and method. A photovoltaic reverse-power monitoring device detects the reverse-power of a grid-connected point, obtains the control power according to the set reverse-power constant value and generates a control signal; the control signal is transmitted to an inverter by a site bus; each inverter feedbacks respective output power to the photovoltaic reverse-power monitoring device in real time; the photovoltaic reverse-power monitoring device gradually adjusts the output of the inverters until electricity generated from the photovoltaic voltage is always in dynamic match with a load; the reverse-power is enabled not to exceed the set value always, the total photovoltaic output power is enabled to be always smaller than but close to the consumed power of the load, and the utilization efficiency of the photovoltaic resource is enable to achieve the best; and smooth and continuous control is carried out on the output power of the inverter, the contradiction between the number of connecting point switches and the control precision is completely solved, and the control effect and safe operational performance are fundamentally improved in comparison with those of the traditional opening loop control.

Description

technical field [0001] The invention belongs to the technical field of photovoltaic reverse power protection, and relates to a photovoltaic reverse power closed-loop control system and method. Background technique [0002] In July 2009, the State Grid Corporation of China issued the "Technical Regulations of the State Grid Corporation of China for Connecting Photovoltaic Power Stations to the Grid (Trial)", which stipulates the general technical requirements for connecting photovoltaic power stations to the grid. Requirements: When the photovoltaic power station is designed to be irreversible grid-connected, reverse power protection equipment should be configured. When it is detected that the reverse current exceeds 5% of the rated output, the photovoltaic power station should stop sending power to the grid line within 0.5-2s. Therefore, the anti-backflow protection device is an indispensable part of the irreversible grid-connected photovoltaic power station. Most small ph...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a photovoltaic reverse power closed-loop control system to solve the contradiction between the number of switches at the access point of the existing reverse power protection system and the control accuracy, and the problem that the mechanical life of the switch element is greatly reduced due to frequent switching

[0005] Another object of the present invention is to provide a photovoltaic inverse power closed-loop control method to solve the problem that the existing step-type energy balance control not only cannot maximize the utilization of photovoltaic power sources, but also causes voltage fluctuations on the power supply bus and reduces the power supply quality of the power grid. question

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