Electric power converting apparatus
First Claim
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1. An electric power converting apparatus for converting a DC voltage into AC phase voltages having 3-leveled potentials, for driving an AC motor, said electric power converting apparatus comprising:
- first means for receiving a DC voltage and producing therefrom an AC voltage in a dipolar modulation mode, to produce a series of output pulses such that each half period of a fundamental wave of an output AC voltage of said electric power converting apparatus is represented by a series of pulses having a zero potential between a positive pulse and a negative pulse;
second means for receiving the DC voltage and producing therefrom an AC voltage in a unipolar modulation mode, to produce a series of output pulses such that each half period of the fundamental wave of the output AC voltage of said electric power converting apparatus is represented by a series of single polarity pulses;
third means for receiving the DC voltage and producing therefrom an AC voltage in an overmodulation mode, to produce a series of output pulses such that each half period of the fundamental wave of the output AC voltage of said electric power converting apparatus is represented by a series of single polarity pulses filled up in the center by a plurality of pulses of the single polarity;
fourth means for receiving the DC voltage and producing therefrom an AC voltage in a 1-pulse mode, to produce an output pulse such that a half period of the fundamental wave of the output AC voltage of said electric power converting apparatus is represented by a single pulse having the same polarity as said half period; and
output means for switching among said first, second, third, and fourth means to change the modulation mode among the dipolar modulation mode, the unipolar modulation mode, the overmodulation mode, and the 1-pulse mode.
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Abstract
An electric power converting apparatus equipped with a 3-level PWM control in which the output voltage can be continuously and smoothly controlled from zero to a maximum voltage. The electric power converting apparatus includes a multi-pulse generating unit arranged for a dipolar modulation, a unipolar modulation, and an overmodulation; a 1-pulse generating means; and a unit for controlling the transfer operation among these modulation regions.
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Citations
21 Claims
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1. An electric power converting apparatus for converting a DC voltage into AC phase voltages having 3-leveled potentials, for driving an AC motor, said electric power converting apparatus comprising:
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first means for receiving a DC voltage and producing therefrom an AC voltage in a dipolar modulation mode, to produce a series of output pulses such that each half period of a fundamental wave of an output AC voltage of said electric power converting apparatus is represented by a series of pulses having a zero potential between a positive pulse and a negative pulse; second means for receiving the DC voltage and producing therefrom an AC voltage in a unipolar modulation mode, to produce a series of output pulses such that each half period of the fundamental wave of the output AC voltage of said electric power converting apparatus is represented by a series of single polarity pulses; third means for receiving the DC voltage and producing therefrom an AC voltage in an overmodulation mode, to produce a series of output pulses such that each half period of the fundamental wave of the output AC voltage of said electric power converting apparatus is represented by a series of single polarity pulses filled up in the center by a plurality of pulses of the single polarity; fourth means for receiving the DC voltage and producing therefrom an AC voltage in a 1-pulse mode, to produce an output pulse such that a half period of the fundamental wave of the output AC voltage of said electric power converting apparatus is represented by a single pulse having the same polarity as said half period; and output means for switching among said first, second, third, and fourth means to change the modulation mode among the dipolar modulation mode, the unipolar modulation mode, the overmodulation mode, and the 1-pulse mode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification