System and method for LLC converter design

Patent metadata

Field	Value
Publication number	US-9906136-B2
Application number	US-201514590778-A
Country	US
Kind code	B2
Filing date	Jan 6, 2015
Priority date	Jan 6, 2015
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

An embodiment method for designing a power converter system includes receiving, by a processor, power converter design parameters. The design parameters include a minimum DC input voltage V min and a maximum DC input voltage V max , a minimum switching frequency f min and a maximum switching frequency f max of a switching bridge of the power converter, and a target output voltage and a target output power. The method also includes calculating, by the processor, a first power converter configuration. The first power converter configuration includes a calculated magnetizing inductance L mc equal to R e tan(φ)(2πf min ) −1 , where φ is a load angle complement equal to a sin(V min V max −1 ), and R e is an equivalent reflected load resistance of the power converter. The first power converter configuration also includes a calculated resonant inductance L rc equal to L mc cos 2 (φ)(f max 2 f min −2 −1) −1 and a calculated resonant capacitance C rc equal to L rc −1 (2πf max ) −2 .

First claim

What is claimed is:

1. A method for designing an inductance-inductance-capacitance (LLC) power converter, the method comprising:
receiving, by a processor, power converter design parameters of the LLC power converter, wherein the LLC power converter comprises a switching bridge coupled to a primary winding of a transformer, a resonant inductor and a resonant capacitor coupled in series between the switching bridge and the primary winding of the transformer, and a secondary side circuit coupled to a secondary winding of the transformer, the power converter design parameters comprising:
a minimum DC input voltage V min and a maximum DC input voltage V max to be received by the switching bridge,
a minimum switching frequency f min and a maximum switching frequency f max of the switching bridge, and
a target output voltage V o and a target output power P o to be output by the secondary side circuit;

calculating, by the processor, a first power converter configuration comprising:
a calculated magnetizing inductance L mc of the primary winding equal to R e tan(φ)(2πf min ) −1 , wherein φ is a load angle complement equal to asin(V min V max −1 ), and R e is an equivalent reflected load resistance of the power converter,
a calculated resonant inductance L rc of the resonant inductor equal to L mc cos 2 (φ)(f max 2 f min −2 −1) −1 , and
a calculated resonant capacitance C rc of the resonant capacitor equal to L rc −1 (2πf max ) −2 ;
writing, by the processor, the first power converter configuration to a non-transitory computer readable medium;
determining layout component values based on the first power configuration; and
physically implementing the LLC power converter using the layout component values.

2. The method of claim 1 , wherein
the power converter design parameters further comprise a switching factor s that is equal to 2 when the switching bridge has a half-bridge configuration and that is equal to 1 when the switching bridge has a full-bridge configuration; and
the first power converter configuration further comprises a calculated turns ratio n c of the primary winding relative to the secondary winding of the transformer comprised in the power converter,
wherein n c is not less than 0.99V max (sV o ) −1 and is not greater than V max (sV o ) −1 ; and the equivalent reflected load resistance R e equals 8π −2 n c 2 V o 2 P o −1 .

3. The method of claim 1 , further comprising graphically displaying the first power converter configuration at a user terminal.

4. The method of claim 3 , wherein
the receiving the power converter design parameters comprises:
receiving a first set of cells in a spreadsheet, wherein values of the first set of cells comprise the power converter design parameters; and

the graphically displaying the first power converter configuration comprises:
displaying a second set of cells in the spreadsheet, wherein values of the second set of cells comprise the first power converter configuration.

5. The method of claim 1 , wherein the non-transitory computer readable medium is a file.

6. The method of claim 5 , further comprising:
receiving, by the processor, a list of available components; and
determining the layout component values comprises selecting, by the processor, layout component values in accordance with the list of available components and the first power converter configuration, the layout component values comprising:
an actual turns ratio n a of the transformer greater than c 1 n c and less than c 2 n c , wherein c 1 is not less than 0.75 and c 2 is not greater than 1.25,
an actual magnetizing inductance L m _ a of the primary winding of the transformer greater than c 1 L m _ c and less than c 2 L m _ c ;
an actual resonant inductance L r _ a of the resonant inductor greater than c 1 L r _ c and less than c 2 L r _ c ; and
an actual resonant capacitance C r _ a of the resonant capacitor greater than c 1 C r _ c and less than c 2 C r _ c .

7. The method of claim 6 , wherein the selecting the layout component values comprises at least one of:
selecting layout components from the list of available components such that the layout component values are closest to component values in the first power converter configuration; and
selecting layout components from the list of available components such that the layout component values jointly maximize a figure of merit in accordance with the first power converter configuration.

8. A power converter design system comprising a non-transitory computer-readable medium storing programming, wherein the programming comprises instructions to:
receive power converter design parameters of an inductance-inductance-capacitance (LLC) power converter, wherein the LLC power converter comprises a switching bridge coupled to a primary winding of a transformer, a resonant inductor and a resonant capacitor coupled in series between the switching bridge and the primary winding of the transformer, and a secondary side circuit coupled to a secondary winding of the transformer, the power converter design parameters comprising:
a minimum DC input voltage V min and a maximum DC input voltage V max to be received by the switching bridge,
a minimum switching frequency f min and a maximum switching frequency f max of the switching bridge, and
a target output voltage V o and a target output power P o to be output by the secondary side circuit; calculate a first power converter configuration comprising:
a calculated magnetizing inductance L mc of the primary winding equal to R e tan(φ)(2πf min ) −1 , wherein φ is a load angle complement equal to asin(V min V max −1 ), and R e is an equivalent reflected load resistance of the power converter,
a calculated resonant inductance L rc of the resonant inductor equal to L mc cos 2 (φ)(f max 2 f min −2 −1) −1 , and
a calculated resonant capacitance C rc of the resonant capacitor equal to L rc −1 (2πf max ) −2 ;

write the first power converter configuration to a non-transitory computer readable medium;
determine layout component values based on the first power configuration; and physically implement the LLC power converter using the layout component values.

9. The system of claim 8 , wherein
the power converter design parameters further comprise a switching factor s that is equal to 2 when the switching bridge has a half-bridge configuration and that is equal to 1 when the switching bridge has a full-bridge configuration; and
the first power converter configuration further comprises a calculated turns ratio n c of the primary winding relative to the secondary winding of a transformer comprised in the power converter,
wherein n c is not less than 0.99V max (sV o ) −1 and is not greater than V max (sV o ) −1 ; and the equivalent reflected load resistance R e equals 8π −2 n c 2 V o 2 P o −1 .

10. The system of claim 8 , wherein the programming further comprises instructions to graphically display the first power converter configuration at a user terminal.

11. The system of claim 10 , wherein
the instructions to receive the power converter design parameters comprise instructions to receive a first set of cells in a spreadsheet, wherein values of the first set of cells comprise the power converter design parameters; and
the instructions to graphically display the first power converter configuration comprise instructions to display a second set of cells in the spreadsheet, wherein values of the second set of cells comprise the first power converter configuration.

12. The system of claim 8 , wherein the non-transitory computer readable medium is

Assignees

• Infineon Tech North America Corp
• Infineon Technologies Austria Ag

Inventors

• Ivankovic Mladen
• Sawyer Fred

Classifications

• Y02B70/1433

  Cross-Sectional Technologies · mapped topic

• H02M3/335 Primary

  using semiconductor devices only · CPC title

• Y02B70/10

  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 title