This application provides a photovoltaic power optimizer and a method and apparatus for controlling same, and a photovoltaic power generation system. The photovoltaic power optimizer includes: a power optimization module, a bypass module, and a control module, where the bypass module is connected to an input end of the power optimization module, an output end of the power optimization module, and the control module, and the control module is connected to the power optimization module; and when detecting that the power optimization module is faulty, the control module is configured to control the bypass module to be on, to bypass the faulty power optimization module, so that the photovoltaic battery component can be directly connected to other battery groups in the photovoltaic power generation system, and connected to an inverter.