The invention relates to a charger and a core controller thereof, and a heat exchange control method. When the charger is in a charging state, the following steps are performed: S10, whether communication between a core controller and a heat exchange controller is interrupted is determined; if not, an S20 is performed; and if so, an S30 is performed; S20, the core controller determines target rotational speeds of an inner fan and an outer fan according to a total output power value of a plurality of power modules in a charger cabinet and first temperature values at air inlets of the power modules and sends the target rotational speed values to the heat exchange controller to adjust rotational speeds of the inner fan and the outer fan; and S30, the heat exchange controller determines targetrotational speeds of the inner fan and the outer fan according to second temperatures at air outlets of the power modules and adjusts the rotational speeds of the inner fan and the outer fan according to the target rotational speeds. Therefore, the charging reliability is improved and energy consumption of the fan is reduced.