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US 2003/0142517 A1Published application
Method for modulating pulse width, power converter, and inverter
AssigneeHitachi, Ltd.
InventorsTeiichi Furukawa, Masahiro Hiraga, Hiroyuki Tomita, Seiji Ishida, Toshiaki Okuyama
Life of this patent
Estimating the term…
Abstract
In calculation 3 phase AC output current Iu, Iv,Iw of an inverter based on the input DC current Idc of the inverter, it is difficult to detect the DC current Idc when the line-to-line voltage pulse width is narrow, thereby the DC current Idc pulse width becomes narrower. The frequency Fc of the carrier wave C is lowered in a phase whose line-to-line voltage is high, thereby the DC current Idc pulse width is set wider. As a result, the current detection is enabled.
Claims22
A method for modulating a pulse width, comprising:
- converting electric power between a DC and an AC by a power converter;
- modulating the pulse width based on a modulated wave and a carrier wave and supplying gate signals to said power converter;
- detecting a current of the DC;
- and
- detecting each phase current of the AC based on the detected DC current and the gate signals;
- wherein the carrier cycle of the carrier wave, when the current is to be detected, is set longer than the carrier cycle to be set when no current is to be detected.
3 more elements
A method for modulating a pulse width, comprising:
- converting electric power between a DC and an AC by a power converter;
- modulating the pulse width based on a modulated wave and a carrier wave with a preset carrier cycle and supplying gate signals to said power converter;
- detecting a current of the DC;
- and
- detecting each phase current of the AC based on the detected DC current and the gate signals;
- characterized by inserting the carrier wave with a long carrier cycle longer than the preset carrier cycle periodically;
- and
- sampling the detected DC current during the long carrier cycle.
5 more elements
A method for modulating a pulse width, comprising:
- converting electric power between a DC and an AC by a power converter;
- modulating the pulse width based on a modulated wave and a carrier wave with a preset carrier cycle and supplying gate signals to said power converter;
- detecting a current of the DC;
- and
- detecting each phase current of the AC based on the detected DC current and the gate signals;
- characterized by inserting the carrier wave with a long carrier cycle of an integer multiple of the preset carrier cycle periodically;
- and
- sampling the current of the DC during the long carrier cycle.
5 more elements
A method for modulating a pulse width, comprising:
- converting electric power between a DC and an AC by a power converter;
- modulating the pulse width based on a modulated wave and a carrier wave with a preset carrier cycle and supplying gate signals to said power converter;
- detecting a current of the DC;
- and
- detecting each phase current of the AC based on the detected DC current and the gate signals;
- characterized by inserting the carrier wave with a long carrier cycle of an integer multiple of the preset carrier cycle around the maximum value of the line-to-line voltage of the AC;
- and
- sampling the current of the DC during the long carrier cycle.
5 more elements
A power converter apparatus, comprising:
- a power converter for converting electric power between a DC and an AC;
- a means for modulating a pulse width based on a modulated wave and a carrier wave with a preset carrier cycle and supplying gate signals to said power converter;
- a means for detecting a current of the DC;
- and
- a means for detecting each phase current of the AC based on the detected DC current and the gate signals;
- characterized by a means for inserting the carrier wave with a long carrier cycle longer than the preset carrier cycle periodically;
- and
- a means for sampling an output of the DC current detecting means.
5 more elements
A power converter apparatus, comprising:
- a power converter for converting electric power between a DC and an AC;
- a means for modulating a pulse width based on a modulated wave and a carrier wave with a preset carrier cycle and supplying gate signals to said power converter;
- a means for detecting a current of the DC;
- and
- a means for detecting each phase current of the AC based on the detected DC current and the gate signals;
- characterized by a means for inserting the carrier wave with a long carrier cycle of an integer multiple of the preset carrier cycle periodically;
- and
- a means for sampling an output of the DC current detecting means.
5 more elements
A power converter apparatus, comprising:
- a power converter for converting electric power between a DC and an AC;
- a means for modulating a pulse width based on a modulated wave and a carrier wave with a preset carrier cycle and supplying gate signals to said power converter;
- a means for detecting a current of the DC;
- and
- a means for detecting each phase current of the AC based on the detected DC current and the gate signals;
- characterized by a means for inserting the carrier wave with a long carrier cycle of an integer multiple of the preset carrier cycle around the maximum value of the line-to-line voltage of the AC, and
- a means for sampling an output of the DC current detecting means.
4 more elements
An inverter apparatus, comprising:
- an inverter for inverting electric power from a DC to a three-phase AC;
- a means for generating an output frequency command for said inverter;
- a means for modulating a pulse width based on a modulated wave depending on the output frequency command and a carrier wave with a preset carrier cycle and supplying gate signals to said inverter;
- a means for detecting a current of the DC;
- and
- a means for detecting each phase current of the three-phase AC based on the detected DC current and the gate signals;
- characterized by a means for inserting the carrier wave with a long carrier cycle longer than the preset carrier cycle;
- and
- a means for sampling an output of the DC current detecting means.
6 more elements
Dependencies are inferred from the claim text.