Sundstrand Corporation

Other

Richard A Arbanella

P John Dhyanchand

Vietson M Nguyen

Albert L Markunas

Vijay K Maddali

John J Dhyanchand

Chai-Nam Ng

Jayant G Vaidya

Raghunath G Mokadam

Rajhunath Mokadam

Christopher E Hopkins

A summing transformer includes first and second sets of primary windings and first and second sets of secondary windings. The primary windings of the first set are connected in a wye configuration whereas the windings of the second set are connected in a delta configuration and the sets of primary windings are connected to form a wye-delta configuration having terminals coupled to the outputs of an inverter bridge. Each winding of the first set of secondary windings is interconnected with a winding of the second set of secondary windings. Circuitry is provided for operating the inverter bridge such that a stepped phase output waveform is produced at each of a plurality of phase outputs.

Stepped-waveform power converter utilizing a summing transformer and a

A control unit for an inverter determines an objective function based upon harmonic content in a minimum number of the phase-to-phase AC voltages produced by the inverter and controls the switches of the inverter so as to minimize the objective function to thus control the harmonic content in the inverter output voltages. The objective function may be defined according to the following equation: ##EQU1## where W.sub.k are scaler weighting factors, A.sub.kA, A.sub.kB and A.sub.kC are the Fourier cosine coefficients of the kth harmonic of the inverter phase A, B and C outputs, B.sub.kA, B.sub.kB and B.sub.kC are the Fourier sine coefficients of the kth harmonic of the inverter phase A, B and C outputs, k is the number of the controlled odd harmonic (i.e., k=1, 3, 5 . . . ), and NHARM is the number of the highest controlled odd harmonic.

Harmonic control for an inverter by use of an objective function

A summing transformer having a core structure, first primary and secondary windings wound on the core structure for establishing a rotating electromagnetic field when the first primary winding is energized, and second primary and secondary windings wound on the core structure for establishing a rotating electromagnetic field when the second primary winding is energized, and wherein the second first and second secondary windings are connected together so that voltages induced therein are added.

Electromagnetic transformer

A summing transformer for a star-delta inverter having a single secondary winding for each group of primary windings for use in inverting variable frequency AC power into constant frequency AC power, the transformer comprising a plurality of core elements having principal legs on which primary windings are wound and secondary legs extending from said principal legs establishing flux paths, the legs of each core element defining apertures through which a single winding is magnetically linked to a group of primary windings.

Summing transformer for star-delta inverter having a single secondary

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Rockford, IL, United States of America

Richard A Arbanella