Switching power supply unit

• US 20080198632A1
• Filed: 02/15/2008
• Published: 08/21/2008
• Est. Priority Date: 02/20/2007
• Status: Active Grant

• Current Assignee: TDK Corporation
• Original Assignee: TDK Corporation
• Inventors: Takayanagi, Yoshinobu
• Granted Patent: US 7,764,527 B2
• Time in Patent Office: Days
• US Class Current: 363/17
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 7/4807 having a high frequency intermediate AC stage
• CPC Class Codes: H02M 7/797 using semiconductor devices only

Abstract

A switching power supply unit is provided, in which input terminals of an AC voltage can be made common to output terminals of an AC voltage. A first switching circuit is provided between a winding of a transformer and a main battery. A second switching circuit is provided between another winding of the transformer and input/output terminals. A third switching circuit is provided between the second switching circuit and the input/output terminals. Each of the first to third switching circuits includes a bidirectional switch (configured of a pair of one switching element and one diode connected in parallel to each other). A circuit for outputting an AC output voltage can be common to a circuit for inputting an AC input voltage to charge the main battery.

Claims

1. A switching power supply unit, comprising:

a transformer including a first transformer coil and a second transformer coil magnetically coupled to each other,

a first bidirectional switching circuit disposed between the first transformer coil and a first DC power supply, and configured to include at least one switch array configured of a pair of switches connected in series,

a second bidirectional switching circuit disposed between the second transformer coil and AC voltage input/output terminals, and configured such that switch arrays are connected in parallel to each other, each of the switch arrays being configured of a pair of switches connected in series,

a third bidirectional switching circuit disposed between the second switching circuit and the AC voltage input/output terminals, and configured to include at least one switch array configured of a pair of switches connected in series, and

a control section controlling the first to third switching circuits.

2. The switching power supply unit according to claim 1:

wherein the control section controls the switching circuits such that;

in output mode where an AC output voltage is outputted from the AC voltage input/output terminals based on a DC input voltage supplied from the first DC power supply, the first and third switching circuits perform DC/AC conversion respectively, and the second switching circuit performs rectification; and

in input mode where a DC output voltage is supplied into the first DC power supply based on an AC input voltage inputted from the AC voltage input/output terminals, the third switching circuit performs AC/DC conversion, the second switching circuit performs DC/AC conversion, and the first switching circuit performs rectification.

3. The switching power supply unit according to claim 2:

wherein the control section controls the switching circuits such that the third switching circuit further performs power-factor improvement in the input mode.

4. The switching power supply unit according to claim 1:

the transformer has a third transformer coil magnetically coupled to the first transformer coil and the second transformer coil, and

a rectifier circuit is further provided between the third transformer coil and a second DC power supply.