LLC RESONANT CONVERTER

• US 20190068065A1
• Filed: 02/08/2018
• Published: 02/28/2019
• Est. Priority Date: 08/28/2017
• Status: Abandoned Application

• Current Assignee: Omron Corporation
• Original Assignee: Omron Corporation
• Inventors: TANINO, Kohei, NAGAOKA, Shingo, SATO, Mitsuru, NAGANO, Masaaki, ONISHI, Hiroyuki
• Application Number:
  US15/892,369
• Publication Number:
  US 20190068065A1
• Time in Patent Office: Days
• CPC Class Codes: H01F 3/14 Constrictions; Gaps, e.g. air-gaps in magnetic shunt paths H01F3/12
• CPC Class Codes: H02M 1/0058 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 Class Codes: H02M 1/40 Means for preventing magnetic saturation
• CPC Class Codes: H02M 3/01 Resonant DC/DC converters
• CPC Class Codes: H02M 3/335 using semiconductor devices only
• CPC Class Codes: H02M 3/33571 Half-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 7/4818 with means for adaptation of resonance frequency, e.g. by modification of capacitance or inductance of resonance circuits
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
• CPC Class Codes: Y02P 80/10 Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier

Abstract

Provided is an LLC resonant converter capable of achieving high efficiency while preventing saturation of a transformer. The LLC resonant converter includes semiconductor switches connected in series between a positive electrode and a negative electrode of a power source, a transformer including a primary winding, a core, and a secondary winding, a capacitor connected between the negative electrode of the power source and a second end of the primary winding of the transformer, a capacitor, and semiconductor switches connected to each other in series and in parallel with the capacitor, and a secondary side circuit connected to the secondary winding of the transformer, wherein the transformer is a swing choke coil.

Claims

1. An LLC resonant converter, comprising:

a first switch and a second switch connected in series between a positive electrode and a negative electrode of a power source,

a transformer including a primary winding having a first end connected to the first switch and the second switch, a core, and a secondary winding,

a first capacitor connected between the negative electrode of the power source and a second end of the primary winding of the transformer,

a second capacitor and a capacitance switch connected to each other in series and in parallel with the first capacitor, and

a secondary side circuit connected to the secondary winding of the transformer,

wherein the secondary side circuit comprises a plurality of diodes and a third capacitor,

wherein the transformer is a swing choke coil.

2. The LLC resonant converter according to claim 1, wherein a gap is provided in the core, and at least one of a pair of opposing magnetic legs with the gap provided therebetween has a cross-sectional area which continuously varies.

3. The LLC resonant converter according to claim 1, wherein a gap is provided in the core, and at least one of a pair of opposing magnetic legs with the gap provided therebetween has a cross-sectional area which varies stepwise.

4. The LLC resonant converter according to claim 1, wherein ON and OFF of the capacitance switch is determined on the basis of an input voltage of the LLC resonant converter or a terminal voltage of a control circuit controlling the capacitance switch.

5. The LLC resonant converter according to claim 2, wherein ON and OFF of the capacitance switch is determined on the basis of an input voltage of the LLC resonant converter or a terminal voltage of a control circuit controlling the capacitance switch.

6. The LLC resonant converter according to claim 3, wherein ON and OFF of the capacitance switch is determined on the basis of an input voltage of the LLC resonant converter or a terminal voltage of a control circuit controlling the capacitance switch.