Driving method of motor fed by electric valve feeding apparatus and the same apparatus
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorMasahiko Akamatsu
Life of this patent
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Abstract
An AC motor having AC windings with an internal electromotive force is driven by an electric valve feeding apparatus having electric valves commutated by the internal electromotive force of the AC windings. The commutation of the electric valve is carried out under the condition of U>.pi./m where m designates the number of commutation times per AC cycle of the electric valve feeding apparatus and U designates a commutation overlapping angle of the electric angle to feed the current to the AC windings whereby the motor is driven by the electric valve feeding apparatus.
Claims31
An electric valve-feeding motor apparatus commutated with internal electromotive force which comprises:
- an AC motor having AC windings which generate an internal electromotive force;
- an electric valve circuit for feeding current to the AC windings;
- and
- means for commutating the electric valves in the electric valve circuit by the internal electromotive force of the AC windings under the driving condition of U>.pi./m wherein m designates the commutation times per one AC cycle of the electric valve circuit and U designates a commutation overlapping angle of the electric valves.
A motor apparatus according to claim wherein the electric valve circuit comprises a plurality of single phase feeding units corresponding to the phases of the AC windings and the AC windings are fed from the single phase feeding units.
An AC motor drive system comprising:
- an AC motor having AC windings, and at least one exciting winding for providing magnetic flux to said AC windings through the air gap of the AC motor itself;
- exciting means for feeding exciting current to said exciting winding;
- a power converter for feeding AC current to said AC windings, said power converter comprising at least a number m of controlled electric valves, m being an integer equal to 8 or more;
- means for proportionately increasing the magnetomotive force generated by the one or several of said exciting windings in response to increasing of the AC current fed to said AC windings;
- turn-on control means for firing said number m of controlled electric valves, the valves being fired with firing electrical angles that are respectively different from each other;
- and
- means for commutating said number m of controlled electric valves by the internal electro-motive forces of said AC windings.
Dependencies are inferred from the claim text.