| US 7,612,518 B2 | ||
| Inverter apparatus and method of reducing speed of alternating current motor | ||
| Hideaki Iura, Kitakyushu (Japan); and Kazuhiko Hiramatsu, Kitakyushu (Japan) | ||
| Assigned to Kabushiki Kaisha Yaskawa Denki, Fukuoka (Japan) | ||
| Appl. No. 11/631,788 PCT Filed Jul. 01, 2005, PCT No. PCT/JP2005/012199 § 371(c)(1), (2), (4) Date Mar. 08, 2007, PCT Pub. No. WO2006/004037, PCT Pub. Date Jan. 12, 2006. |
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| Claims priority of application No. 2004-199699 (JP), filed on Jul. 06, 2004. | ||
| Prior Publication US 2007/0216328 A1, Sep. 20, 2007 | ||
| Int. Cl. H02P 27/06 (2006.01) | ||
| U.S. Cl. 318—762 [318/800; 318/801; 318/811] | 30 Claims |
| 1. An inverter apparatus comprising:
a converter portion for converting an alternating current voltage into a direct current voltage,
a capacitor for smoothing the direct current voltage,
an inverter portion for driving an alternating current motor by converting the direct current voltage into an alternating
current,
a current converting portion for generating a detecting value of a current flowing in the motor, and
a PWM calculating portion for generating a signal for driving a gate of a power element,
a direct current voltage detecting portion for detecting the direct current voltage;
a first filter portion and a second filter portion constituting two low pass filters for filtering an output of the direct
current voltage detecting portion;
a speed reducing rate setting portion for setting a speed reducing time period of the motor;
a speed reducing rate calculating portion for calculating a frequency of driving the motor from an output of the first filter
portion and an output of the speed reducing rate setting portion; and
a voltage command correcting portion for correcting a voltage command from an output of the second filter portion and a given
voltage command, wherein
in speed reducing, a time constant of the second filter portion is constituted by 10 through 10000 times as much as a time
constant of the first filter portion.
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