Fault riding-through method and device and photovoltaic power generation system

Abstract

The invention discloses a fault riding-through method applicable to a photovoltaic power generation system. The fault riding-through method comprises the following steps: acquiring a voltage deviationamount and a measured current value of a photovoltaic panel, and converting the voltage deviation amount into a current inner loop reference value; judging whether a voltage deviation amount of a direct current busbar is greater than a dead zone threshold value; if the voltage deviation amount of the direct current busbar is greater than the dead zone threshold value, outputting a deviation valuebetween the voltage deviation amount of the direct current busbar and the dead zone threshold value, and multiplying the deviation value by a proportional coefficient to obtain a current deviation amount; calculating a value obtained by subtracting the measured current value of the photovoltaic panel and the current deviation amount from the current inner loop reference value to obtain a currentreference value of the photovoltaic panel; converting the current reference value into a duty cycle signal so as to enable the photovoltaic power generation system to control the stability of the voltage of the direct current busbar according to the duty cycle signal. The invention further discloses a fault riding-through device and the photovoltaic power generation system. Under the premise of nocommunication, effective limitation of the injection power of the photovoltaic panel during an alternating current grid failure can be achieved, fluctuation of the voltage of the direct current busbar is reduced, and ultimately the fault ride-through of the photovoltaic power generation system is achieved.

Description

technical field [0001] The invention relates to the technical field of photovoltaic power generation, in particular to a fault ride-through method, device and photovoltaic power generation system. Background technique [0002] At present, with the rapid decline in the cost of development and application of renewable energy. The installed capacity of power generation systems such as wind power and photovoltaics continues to increase. In 2015, the newly installed capacity of global renewable energy power generation exceeded the installed capacity of conventional energy power generation for the first time, indicating that the construction of the global power system is undergoing structural changes. [0003] In the photovoltaic power generation process of the prior art, the electric energy generated by the photovoltaic power generation system is first boosted by a DC-DC (direct current-direct current) converter, collected and merged into the DC bus, and then passed through a DC...

AI Technical Summary

Problems solved by technology

When the AC power grid fails, if the DC-AC converter detects the fault and transmits this signal to the DC boost controller through communication, the injected power of the DC-DC converter can be reduced, thereby reducing the DC bus voltage, but the DC boost There is a certain delay in the communication between the voltage controller and the power-current dual-loop controller, and the control response speed of the DC bus voltage is relatively slow

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