Three-phase DC-to-AC power inverter with three-level poles
First Claim
1. Apparatus for converting a dc voltage to a three-phase ac voltage controlled in magnitude and phase for use in an electric power system, said apparatus comprising:
- a dc voltage source having a positive voltage node, a negative voltage node, and a zero voltage node;
a plurality of three-level poles each connected to said positive voltage node, said negative voltage node and said zero voltage node, and each connected to an associated ac output terminal and being responsive to pole control signals to selectively connect said associated ac output terminal to one of said positive, negative and zero voltage nodes;
means connected to said ac output terminal of each of said plurality of three-level poles to generate a harmonic neutralized three-phase ac output voltage; and
vector control means generating said pole control signals to produce said three-phase harmonic neutralized ac output voltage with a selected magnitude and phase angle.
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Accused Products
Abstract
A three-phase dc to-ac power inverter includes a dc power source with a first dc node for positive voltage, a second dc node for negative voltage, and a third dc node for zero voltage. A set of three-level pole circuits are connected to the first dc node, the second dc node, and the third dc node of the dc power source. A control circuit, responsive to an inverter voltage vector reference demand signal with a voltage magnitude reference demand component and a voltage phase reference demand component, generates pole control signals for the three-level pole circuits using logic circuitry which combines phase indexed digital waveform values stored in a pair of lookup tables. The pole control signals force the three-level pole circuits to generate a set of phase-shifted waveforms with zero voltage components. The phase-shifted waveforms are combined by a set of transformers to produce a three-phase output voltage with a harmonic content lower than the harmonic content of the phase-shifted waveforms.
23 Citations
9 Claims
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1. Apparatus for converting a dc voltage to a three-phase ac voltage controlled in magnitude and phase for use in an electric power system, said apparatus comprising:
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a dc voltage source having a positive voltage node, a negative voltage node, and a zero voltage node; a plurality of three-level poles each connected to said positive voltage node, said negative voltage node and said zero voltage node, and each connected to an associated ac output terminal and being responsive to pole control signals to selectively connect said associated ac output terminal to one of said positive, negative and zero voltage nodes; means connected to said ac output terminal of each of said plurality of three-level poles to generate a harmonic neutralized three-phase ac output voltage; and vector control means generating said pole control signals to produce said three-phase harmonic neutralized ac output voltage with a selected magnitude and phase angle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification