Voltage conversion device and method of deciding leakage inductance
AssigneeSumitomo Electric Industries, Ltd.
InventorsKeiji Tashiro, Xiaoguang Zheng
Life of this patent
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Abstract
Provided is a voltage conversion device including: a voltage conversion circuit having two inductors that are wound around a core and that magnetically cancel each other out, and switching elements that switch current flowing through the respective inductors; and a control unit that alternately turns on and off each of the switching elements. The coupling coefficient of the two inductors is in the range from −0.99 to −0.78.
Claims6
A voltage conversion device, comprising:
- a voltage conversion circuit including two inductors that are wound around a core and that magnetically cancel each other out, and switching elements that respectively switch current flowing through the two inductors;
- and
- a control unit that alternately turns on and off each of the switching elements,
- wherein the two inductors have a coupling coefficient in a range from −0.99 to −0.78 and
- a magnitude of leakage inductance of the two inductors corresponds to a value less than one time and 0.45 times or more of a magnitude of self inductance that is required to reduce ripple current flowing through the two inductors at a predetermined reduction rate, in a case where the coupling coefficient of the two inductors is 0.
A voltage conversion device, comprising:
- a voltage conversion circuit including two inductors that are wound around a core and that magnetically cancel each other out, and switching elements that respectively switch current flowing through the two inductors;
- and
- a control unit that alternately turns on and off each of the switching elements,
- wherein the two inductors have a coupling coefficient in a range from −0.99 to −0.78,
- the voltage conversion device comprises N sets of the voltage conversion circuits (N is a natural number larger than 1),
- the N sets of the voltage conversion circuits are connected in parallel to one another, and
- the control unit turns on and off the switching elements of each of the voltage conversion circuits with phases each shifted by π/N.
A method of deciding leakage inductance of two inductors in a voltage conversion device including switching elements that respectively switch current flowing through the two inductors that are wound around a core and magnetically cancel each other out, each of the switching elements being turned on or off by a control unit, comprising:
- preparing two first inductors with a coupling coefficient of 0, and two second inductors having leakage inductance of a same magnitude as self inductance of the first inductors and a coupling coefficient close to −1;
- connecting the two first inductors in place of the two inductors;
- obtaining a first change characteristic with respect to a duty ratio in a predetermined range where the control unit turns on each of the switching elements, for ripple current flowing through the first inductors;
- connecting the two second inductors in place of the two first inductors;
- obtaining a second change characteristic with respect to the duty ratio in the predetermined range, for ripple current flowing through the second inductors;
- calculating a reduction rate of ripple current based on a result obtained by comparing the obtained first and second change characteristics with each other;
- setting a reduction rate of the magnitude of leakage inductance of the second inductors to a reduction rate equal to or lower than the calculated reduction rate of ripple current;
- deciding a magnitude of leakage inductance of the two inductors so as to obtain the reduction rate;
- and
- setting a coupling coefficient of the two second inductors as a coupling coefficient of the two inductors.
Dependencies are inferred from the claim text.