a conversion unit;

a photovoltaic module, wherein an input end of the conversion unit is configured to be connected to one or more photovoltaic modules and perform power conversion on a connected photovoltaic module;

a control unit, configured to control the conversion unit; and

an auxiliary power source, wherein the auxiliary power source is configured to provide a working voltage for the control unit;

an energy storage unit, wherein the energy storage unit is configured to provide electric energy for the auxiliary power source or the control unit; and

a first unidirectional conduction unit, wherein the first unidirectional conduction unit, the energy storage unit, and the auxiliary power source are electrically connected between the conversion unit and the control unit and the first unidirectional conduction unit is configured to prevent the electric energy of the energy storage unit from falling with a decrease of a voltage of the photovoltaic module,

wherein the control unit is further configured to perform current-voltage IV curve scans for voltage segments, wherein the voltage segments are in a range of an output voltage of the photovoltaic module from an open-circuit voltage to a preset minimum voltage, and there are at least two voltage segments, wherein

a first width of a first voltage segment of the voltage segments along a voltage axis of the IV curve is different from a second width of a second voltage segment of the voltage segments along the voltage axis of the IV curve.