Method of and apparatus for controlling converter
AssigneeDaikin Industries, Ltd.
InventorKenichi Sakakibara
Life of this patent
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Abstract
Controlled by switching is which reactor in a reactor group present between a power source and a three-level converter is to be connected to an intermediate point that outputs a midpoint potential. In the switching, the closer to the command value of the midpoint potential the command values of input potentials of the converter are, the greater the duty at which corresponding reactors are connected to the intermediate point is for pulse width modulation. Additionally, a predetermined range to be compared with the command values has a predetermined potential width with respect to an AC waveform centered around the command value of the midpoint potential.
Claims12
A method of controlling a converter,
- said converter including
- a rectifier circuit for outputting a low potential, a high potential higher than said low potential, and a midpoint potential between said low potential and said high potential,
- a first capacitor receiving said low potential and said midpoint potential, and
- a second capacitor connected at a connection point to said first capacitor, and receiving said high potential and said midpoint potential,
- said rectifier circuit including
- a three-phase diode bridge for rectifying first to third potentials at second ends of a set of three reactors, respectively, having first ends to which a three-phase voltage is applied, to thereby output said low potential and said high potential, and
- a switch group for selectively connecting said second ends of said three reactors to said connection point,
- wherein, when first to third command values that are command values for said first to third potentials, respectively, are in a predetermined range, said switch group connects said second ends corresponding to the respective command values to said connection point, and
- wherein a range having a predetermined potential width with respect to an AC waveform centered around the command value of said midpoint potential is used as said predetermined range.
An apparatus for controlling a converter,
- said converter including
- a rectifier circuit for outputting a low potential, a high potential higher than said low potential, and a midpoint potential between said low potential and said high potential,
- a first capacitor receiving said low potential and said midpoint potential, and
- a second capacitor connected at a connection point to said first capacitor, and receiving said high potential and said midpoint potential,
- said rectifier circuit including
- a three-phase diode bridge for rectifying first to third potentials at second ends of a set of three-reactors, respectively, having first ends to which a three-phase voltage is applied, to thereby output said low potential and said high potential, and
- a switch group for selectively connecting said second ends of said three reactors to said connection point,
- said apparatus comprising:
- a voltage command value generating section for generating first to third command values that are command values for said first to third potentials, respectively, from said three-phase voltage;
- and
- a pulse width modulator for generating switching signals for causing said switch group to connect said second ends corresponding to the respective command values to said connection point when said respective first to third command values are in a range having a predetermined potential width with respect to an AC waveform centered around the command value of said midpoint potential.
Dependencies are inferred from the claim text.