An energy balance controller includes a detection unit, a calculation unit and a reset integral module; the reset integral module includes a reset integrator, a comparator and an RS flip-flop; the input terminals of the calculation unit and the reset integrator are connected to the output terminal of the detection unit, respectively; the output terminal of the calculation unit is connected to one input terminal of the comparator, and the output terminal of the reset integrator is connected to the other input terminal of the comparator; the output terminal of the comparator is connected to the reset terminal of the RS flip-flop; the Q terminal of the RS flip-flop is connected to the reset integrator, and the Q terminal of the RS flip-flop is used for controlling a switching device of the converter to switch on or off; the method is implemented by the energy balance controller.