Neutral forming circuit
First Claim
1. A neutral forming circuit which develops a neutral voltage relative to an AC voltage produced at an output frequency by an inverter coupled to first and second DC link conductors, comprising:
- first and second impedances coupled together at a junction to form a series combination which is coupled across the DC link conductors; and
a third impedance coupled between the junction and a neutral terminal at which the neutral voltage is formed, the first through third impedances forming a resonant circuit having a resonant frequency substantially equal to the output frequency of the inverter.
1 Assignment
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Accused Products
Abstract
Prior neutral forming circuits for use in developing a neutral voltage for loads coupled to an inverter have been unduly large and heavy or have required that the inverter be operated by a half bridge control which causes less easily filtered harmonics to be produced in the inverter output. In order to overcome these problems, a neutral forming circuit includes first and second impedances coupled together at a junction to form a series combination which is coupled across a pair of DC link conductors coupled to an inverter input and a third impedance coupled between the junction and a neutral terminal at which the neutral voltage is formed, the first through third impedances forming a resonant circuit having a resonant frequency substantially equal to the output frequency of the inverter.
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Citations
5 Claims
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1. A neutral forming circuit which develops a neutral voltage relative to an AC voltage produced at an output frequency by an inverter coupled to first and second DC link conductors, comprising:
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first and second impedances coupled together at a junction to form a series combination which is coupled across the DC link conductors; and a third impedance coupled between the junction and a neutral terminal at which the neutral voltage is formed, the first through third impedances forming a resonant circuit having a resonant frequency substantially equal to the output frequency of the inverter. - View Dependent Claims (2, 3)
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4. A neutral forming circuit which develops a neutral voltage relaive to three-phase AC voltages produced at an output frequency by a three-phase inverter operated by a full bridge inverter control and having inputs coupled to first and second DC link conductors, comprising:
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first and second capacitors coupled together at a junction to form a series combination which is coupled across the DC link conductors; and an inductor coupled between the junction and a neutral terminal at which the neutral voltage is formed, the capacitors and inductor forming a resonant circuit having a resonant frequency substantially equal to the output frequency of the inverter. - View Dependent Claims (5)
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Specification