An apparatus for reducing the heat losses caused by the DC Bus capacitor current is proposed. The apparatus includes: a double frequency boost converter circuit having two boost converter circuits coupled in parallel, in which two switches, respectively disposed on the two boost converter circuits, are turned on and off alternately to produce an output current having a frequency twice that of control signals of the two switches, and to offer a DC bus respectively, a full-bridge DC-DC converter coupled to an output terminal of the double frequency boost converter circuit for transforming an output of the DC bus to a DC voltage, and a DC bus capacitor coupled to the double frequency boost converter circuit and the full-bridge DC-DC converter in parallel for balancing two corresponding transient powers of the double frequency boost converter circuit and the full-bridge DC-DC converter respectively.
A DC-AC converter is applicable for transforming direct current (DC) to alternating current (AC). The DC-AC converter includes a voltage boost module and a DC-AC converter module. Herein the voltage boost module includes a voltage bypass circuit and a voltage boost circuit, both of which receive input voltage from DC input power. Meantime, the voltage bypass circuit sends out the received input voltage, and the voltage boost circuit will operate to increase DC output voltage from the DC input as the DC output voltage from the voltage bypass circuit is not high enough to meet requirement by AC output power. The DC-AC converter module receives the output voltage from the voltage boost module and converts the received voltage to the required AC output power.
In one aspect, a switch mode power supply comprises a first inductive element; a first switching element, wherein a first end of the first switching element is connected to a second end of the first inductive element; a second inductive element; a second switching element, wherein a first end of the second switching element is connected to a second end of the second inductive element; and wherein a first power source terminal is connected to a first end of the first inductive element and a first end of the second inductive element, and a second power source terminal is connected to a second end of the first switching element and a second end of the second switching element, and wherein a load is connected to the first end of the first switching element and the first end of the second switching element.
A power factor correction (PFC) circuit includes a coupled split boost choke having at least two windings, at least two boost diodes and at least two power rails. Each power rail includes one of the windings and one of the boost diodes. The PFC circuit further includes a current balancing circuit coupled between the power rails for substantially balancing currents in such power rails.
