PHOTOVOLTAIC CONVERTER MODULE STRING, CONTROL METHOD, AND SYSTEM

This application provides a photovoltaic converter string, a control method, and a system, to control, to be conducted, one of switching transistors in a buck/boost circuit of a photovoltaic converter that are connected in parallel to a bypass diode, and also control the other switching transistors in the buck/boost circuit of the photovoltaic converter to be cut off. Therefore, an output voltage of the photovoltaic converter is applied to both ends of the non-conducted switching transistor in the switching transistors connected in parallel to the bypass diode, and after the output voltage of the photovoltaic converter reaches a breakdown voltage of the non-conducted switching transistor, an avalanche breakdown occurs on the non-conducted switching transistor, the switching transistor undergoing the breakdown dissipates excess energy in a form of heat, and a voltage of both ends of the bypass diode connected to a positive output end and a negative output end of the photovoltaic converter is clamped to be less than or equal to the breakdown voltage of the switching transistor. In this way, the voltage that the bypass diode withstands is less than or equal to the breakdown voltage of the non-conducted switching transistor, thereby preventing the bypass diode from withstanding an excessively high output voltage and preventing the bypass diode from being damaged due to an excessively high output voltage.