Transformer and resonant circuit having same

Patent metadata

Field	Value
Publication number	US-10984945-B2
Application number	US-201615751881-A
Country	US
Kind code	B2
Filing date	Sep 30, 2016
Priority date	Oct 5, 2015
Publication date	Apr 20, 2021
Grant date	Apr 20, 2021

Abstract

Provided is a transformer ( 1 ), which includes: a core ( 10 ) which forms a magnetic circuit and has a middle leg ( 10 a ) and a plurality of side legs ( 10 b, 10 c ) branched from the middle leg ( 10 a ); primary windings ( 11 ) respectively wound around a first winding leg ( 10 a ) and a second winding leg ( 10 b ), which are selected from the middle leg ( 10 a ) and the side legs ( 10 b, 10 c ); and a secondary winding ( 12 ) wound around either of the first winding leg ( 10 a ) or the second winding leg ( 10 b ), wherein a first magnetic flux generated by the primary windings ( 11 ) from the first winding leg ( 10 a ) and a second magnetic flux generated by the primary windings ( 11 ) from the second winding leg ( 10 b ) differ from each other by a predetermined value or more at a position at which the fluxes do not intersect with the secondary winding ( 12 ).

First claim

The invention claimed is:

1. A transformer, characterized in comprising:
a core configured to form a magnetic circuit and have a middle leg and a plurality of side legs branching off from the middle leg;
primary windings respectively wound around the middle leg and one of the side legs, wherein winding direction of the primary winding wound around the middle leg and winding direction of the primary winding wound around the one of the side legs are opposite to each other; and
a secondary winding wound around the one of the side legs,
wherein a first magnetic flux generated by the primary windings from the middle leg and a second magnetic flux generated by the primary windings from the one of the side legs differ from each other by a predetermined value or more at a position at which the fluxes do not intersect with the secondary winding,
wherein a cross-sectional area of the primary winding differs at the middle leg and the one of the side legs.

2. The transformer according to claim 1 , characterized in that the core has a path of the magnetic flux, which does not intersect with the secondary winding, of the first magnetic flux and the second magnetic flux which are generated by the primary windings.

3. The transformer according to claim 2 , characterized in that a gap is provided in the path.

4. The transformer according to claim 1 , characterized in that the number of turns of the primary winding differs at the middle leg and the one of the side legs.

5. The transformer according to claim 1 , characterized in that a gap is provided in either the middle leg or the one of the side legs, or gaps having different lengths are respectively provided in the middle leg and the one of the side legs.

6. A resonant circuit, characterized in comprising:
the transformer according to claim 1 ;
a resonant inductance; and
a resonant capacitor,
wherein the resonant circuit uses resonance of the resonant inductance and the resonant capacitor connected to an excitation inductance of the transformer.

7. The resonant circuit according to claim 6 , characterized in that the resonant inductance and the resonant capacitor are connected in series to the excitation inductance.

8. The resonant circuit according to claim 7 , characterized in that:
the resonant circuit is an LLC type resonant circuit; and
the excitation inductance/the resonant inductance ≤3.

9. The transformer according to claim 2 , characterized in that the number of turns of the primary winding differs at the middle leg and the one of the side legs.

10. The transformer according to claim 3 , characterized in that the number of turns of the primary winding differs at the middle leg and the one of the side legs.

11. The transformer according to claim 2 , characterized in that a gap is provided in either the middle leg or the one of the side legs, or gaps having different lengths are respectively provided in the middle leg and the one of the side legs.

12. The transformer according to claim 3 , characterized in that a gap is provided in either the middle leg or the one of the side legs, or gaps having different lengths are respectively provided in the middle leg and the one of the side legs.

13. The transformer according to claim 4 , characterized in that a gap is provided in either the middle leg or the one of the side legs, or gaps having different lengths are respectively provided in the middle leg and the one of the side legs.

14. A resonant circuit, characterized in comprising:
the transformer according to claim 2 ;
a resonant inductance; and
a resonant capacitor,
wherein the resonant circuit uses resonance of the resonant inductance and the resonant capacitor connected to an excitation inductance of the transformer.

15. The resonant circuit according to claim 14 , characterized in that the resonant inductance and the resonant capacitor are connected in series to the excitation inductance.

16. The resonant circuit according to claim 15 , characterized in that:
the resonant circuit is an LLC type resonant circuit; and
a ratio between the excitation inductance and the resonant inductance is less than or equal to 3.

Assignees

• Omron Tateisi Electronics Co

Inventors

• Nagaoka Shingo
• Zaitsu Toshiyuki
• Okuno Yutaro
• Morishita Sadaharu

Classifications

• H02M3/003

  Constructional details, e.g. physical layout, assembly, wiring or busbar connections · CPC title

• H02M3/33571

  Half-bridge at primary side of an isolation transformer · CPC title

• H02M3/01

  Resonant DC/DC converters · CPC title

• H02M1/0064

  Magnetic structures combining different functions, e.g. storage, filtering or transformation · CPC title

• H02M1/0058

  by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero (using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826) · CPC title