Electric power conversion apparatus for plural DC voltage sources and an AC electrical load
First Claim
1. An electric power conversion apparatus comprising:
- a power converter adapted to be electrically connected to at least a first DC voltage source, a second DC voltage source and an AC electrical load, and configured to generate an individual output voltage pulse train from an output voltage of each of the DC voltage sources in accordance with a switch drive signal set, to synthesize a final output voltage from the individual output voltage pulse trains, and to drive the load with the final output voltage; and
a power-converter control unit configured to control the switch drive signal set, the power-converter control unit including a PWM pulse generation section configured to perform the following;
comparing a voltage command value with a PWM carrier for each of the DC voltage sources; and
generating based on the comparison a first PWM pulse train for supplying a first output voltage pulse train from the first DC voltage source to the load and a second PWM pulse train for supplying a second output voltage pulse train from the second DC voltage source to the load in such a manner to form a pulse continuous in time in the final output voltage at least from each pulse of the first output voltage pulse train and a subsequent pulse of the second output voltage pulse train,wherein;
the power converter includes a plurality of phase sections;
each of the phase sections includes a first switch, a second switch, a third switch, and a contact connected to the load, and connects the DC voltage sources in parallel;
the second switch is connected between a first pole of the first DC voltage source and the contact;
the third switch is connected between a first pole of the second DC voltage source and the contact;
the first switch is connected between the contact and a set of second poles of the DC voltage sources; and
the power-converter control unit controls the switch drive signal set in such a manner that a first period when the first switch is in an ON state, a second period when the second switch is in an ON state, and a third period when the third switch is in an ON state, are prevented from overlapping with each other, and the second period is continuous with the third period.
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Accused Products
Abstract
An electric power conversion apparatus includes a power converter connected to at least a first DC voltage source, a second DC voltage source and an AC electric motor. A control unit controls the power converter to generate a first PWM pulse train for supplying a first output voltage pulse train from the first DC voltage source to the AC electric motor and a second PWM pulse train for supplying a second output voltage pulse train from the second DC voltage source to the load in such a manner to form a pulse continuous in time in a final output voltage at least from each pulse of the first output voltage pulse train and a subsequent pulse of the second output voltage pulse train. A current path is provided constantly from the AC electric motor to at least one of the DC voltage sources.
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Citations
16 Claims
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1. An electric power conversion apparatus comprising:
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a power converter adapted to be electrically connected to at least a first DC voltage source, a second DC voltage source and an AC electrical load, and configured to generate an individual output voltage pulse train from an output voltage of each of the DC voltage sources in accordance with a switch drive signal set, to synthesize a final output voltage from the individual output voltage pulse trains, and to drive the load with the final output voltage; and a power-converter control unit configured to control the switch drive signal set, the power-converter control unit including a PWM pulse generation section configured to perform the following; comparing a voltage command value with a PWM carrier for each of the DC voltage sources; and generating based on the comparison a first PWM pulse train for supplying a first output voltage pulse train from the first DC voltage source to the load and a second PWM pulse train for supplying a second output voltage pulse train from the second DC voltage source to the load in such a manner to form a pulse continuous in time in the final output voltage at least from each pulse of the first output voltage pulse train and a subsequent pulse of the second output voltage pulse train, wherein; the power converter includes a plurality of phase sections; each of the phase sections includes a first switch, a second switch, a third switch, and a contact connected to the load, and connects the DC voltage sources in parallel; the second switch is connected between a first pole of the first DC voltage source and the contact; the third switch is connected between a first pole of the second DC voltage source and the contact; the first switch is connected between the contact and a set of second poles of the DC voltage sources; and the power-converter control unit controls the switch drive signal set in such a manner that a first period when the first switch is in an ON state, a second period when the second switch is in an ON state, and a third period when the third switch is in an ON state, are prevented from overlapping with each other, and the second period is continuous with the third period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An electric power conversion apparatus, comprising:
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a power converter adapted to be electrically connected to at least a first DC voltage source, a second DC voltage source and an AC electrical load, and configured to generate an individual output voltage pulse train from an output voltage of each of the DC voltage sources in accordance with a switch drive signal set, to synthesize a final output voltage from the individual output voltage pulse trains, and to drive the load with the final output voltage; and a power-converter control unit configured to control the switch drive signal set, the power-converter control unit including a PWM pulse generation section configured to perform the following; comparing a voltage command value with a PWM carrier for each of the DC voltage sources; and generating based on the comparison a first PWM pulse train for supplying a first output voltage pulse train from the first DC voltage source to the load and a second PWM pulse train for supplying a second output voltage pulse train from the second DC voltage source to the load in such a manner to form a pulse continuous in time in the final output voltage at least from each pulse of the first output voltage pulse train and a subsequent pulse of the second output voltage pulse train, wherein the PWM pulse generation section is configured to perform the following; comparing in magnitude the output voltages of the DC voltage sources; providing based on the comparison a short-circuit prevention period in such a manner to prevent a short circuit from an electric pole having a higher electric potential to an electric pole having a lower electric potential; and allowing based on the comparison a short circuit from an electric pole having a lower electric potential to an electric pole having a higher electric potential in such a manner to provide constantly a current path from the load to at least one of the DC voltage sources. - View Dependent Claims (11)
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12. An electric power conversion apparatus, comprising:
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a power converter adapted to be electrically connected to at least a first DC voltage source, a second DC voltage source and a load including an AC electrical load, and configured to generate an individual output voltage pulse train from an output voltage of each of the DC voltage sources in accordance with a switch drive signal set, to synthesize a final output voltage from the individual output voltage pulse trains, and to drive the load with the final output voltage; and a power-converter control unit configured to control the switch drive signal set, the power-converter control unit including a PWM pulse generation section configured to perform the following; comparing a voltage command value with a PWM carrier for each of the DC voltage sources; and generating based on the comparison a first PWM pulse train for supplying a first output voltage pulse train from the first DC voltage source to the load and a second PWM pulse train for supplying a second output voltage pulse train from the second DC voltage source to the load in such a manner to form a pulse continuous in time in the final output voltage at least from each pulse of the first output voltage pulse train and a subsequent pulse of the second output voltage pulse train, wherein the power-converter control unit is configured to perform the following; computing a voltage correction value for each of the DC voltage sources based on values of the output voltages of the DC voltage sources and the sign of an associated phase current value; and correcting a voltage command value allocated to each of the DC voltage sources by adding the voltage correction value. - View Dependent Claims (13, 14, 15, 16)
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Specification