Control method for photovoltaic rapid switching-off system, and application apparatus and system therefor

A method for controlling a photovoltaic rapid shutdown system, comprising:

• determining, by an inverting system in the photovoltaic rapid shutdown system, whether the photovoltaic rapid shutdown system is to enter a safe mode;
• introducing, by the inverting system, fluctuations onto a direct-current bus in the photovoltaic rapid shutdown system, in response to the photovoltaic rapid shutdown system being not to enter the safe mode;
• not introducing, by the inverting system, the fluctuations onto the direct-current bus in the photovoltaic rapid shutdown system, in a case that the photovoltaic rapid shutdown system being to enter the safe mode;
• determining, by a shutdown device for a photovoltaic module in the photovoltaic rapid shutdown system according to an output parameter of the shutdown device, whether an electrical parameter on the direct-current bus connected to the shutdown device meets a preset condition;
• controlling, by the shutdown device, the shutdown device to be turned on, or maintaining the shutdown device being on, in response to the electrical parameter on the direct-current bus connected to the shutdown device meeting the preset condition;
• and
• controlling, by the shutdown device, the shutdown device to be turned off, or maintaining the shutdown device being off, in response to the electrical parameter on the direct-current bus connected to the shutdown device not meeting the preset condition;
• wherein:
• the fluctuations comprise voltage fluctuations, and the electrical parameter comprises a voltage on the direct-current bus;
• the fluctuations comprise current fluctuations, and the electrical parameter comprises a current on the direct-current bus;
• or
• the fluctuations comprise voltage fluctuations and current fluctuations, and the electrical parameter comprises a voltage and a current on the direct-current bus;
• wherein before introducing, by the inverting system, the fluctuations onto the direct-current bus in the photovoltaic rapid shutdown system, the method further comprises:
• determining, by the inverting system, whether there is a fault in the photovoltaic rapid shutdown system;
• performing the step of introducing, by the inverting system, the fluctuations onto the direct-current bus, in response to there being no fault in the photovoltaic rapid shutdown system;
• and
• performing the step of not introducing, by the inverting system, the fluctuations onto the direct-current bus, in response to there being the fault in the photovoltaic rapid shutdown system.