The invention discloses a method for reducing
capacitance in a single-phase
pulse load AC-DC power source and belongs to the power electronic converter field. The single-phase
pulse load AC-DC power source needs to implement a PFC function at an input AC side, which will introduce second
harmonic current into a PFC
busbar, and therefore, a large-
capacitance capacitor is required to be arranged onthe PFC
busbar so as to decouple the second
harmonic current; the single-phase
pulse load AC-DC power source also needs an output
voltage under the condition of a pulse load to be stabilized within acertain range at an output side, the
pulse current of the output side is transmitted to the PFC
busbar, and as a result, a large-
capacitance capacitor is required to decouple the
pulse current; the large-capacitance capacitors for the above two purposes will reduce the
power density of a converter; in order to improve the
power density of the converter, a bidirectional converter is connected in parallel with the PFC output busbar so as to act as a controlled
current source; the input current of the controlled
current source is controlled according to a power conservation method, and at the same time, the second
harmonic current and
pulse current are decoupled; and therefore, the
voltage ripples of a PFC busbar
capacitor can be decreased, and the
power density of the converter can be improved.