Frequency current converter for energizing an AC machine
AssigneeJeumont-Schneider Corporation
InventorsAlbert C. Wiart, Pierre J. DE LA Jonquiere
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Abstract
An adjustable current input inverter-induction motor drive using a commutation bridge associated with a common commutating capacitor and four commutating thyristors. Capacitive means is provided for transferring energy during commutation from one main thyristor branch to the next in sequence through the inverter, and a capacitor inputting in a transformer and full wave rectifier bridge is provided coupled to said capacitive means for recuperating excess energy and for restitution thereof into the DC link of the inverter.
Claims13
A variable frequency current converter for energizing an alternating current polyphase motor from an adjustable direct current source comprising:
- a direct current power supply;
- a current-fed inverter responsive to said direct current power supply including a plurality of paired main thyristors mounted in a bridge between corresponding phases of said motor and two pole terminals;
- a commutation bridge including a plurality of paired diodes mounted in a bridge between corresponding phases of said motor and two commutation poles;
- a common commutation capacitor operatively controlled concurrently with firing of an on-coming one of said paired main thyristors for turning off and off-going one of said paired main thyristors, said on-coming and off-going main thyristors being associated with a common one of said pole terminals and the commutation process being caused by said commutation capacitor through one of said paired diodes of said commutation bridge associated with the one of said commutation poles opposite to said one pole terminal;
- with capacitor means connected between said commutation poles and charged during the commutation process for transferring energy from the motor phase related to said off-going main thyristor to the motor phase related to said on-coming main thyristor via said one diode of said commutation bridge.
A current-fed inverter for supplying variable frequency alternating current to an n phase motor from an adjustable direct current source comprising:
- a. a switching bridge for selectively passing said direct current to 2n main thyristors mounted by pairs in n parallel branches, each pair of thyristors having a junction point connected to a corresponding phase of said motor,
- b. a commutation bridgeincluding 2n commutation diodes mounted by pairs in n parallel branches, each pair of commutation diodes having a junction point connected to a corresponding phase of said motor,
- c. two commutation circuits for said main thyristors, said commutation circuits having in common a commutation capacitor, each commutation circuit including two commutation thyristors, one commutation thyristor of a commutation circuit being associated with a point common to the n main thyristors of one polarity, the other commutation thyristor of the same commutation circuit being associated with a point common to the n commutation diodes of the same polarity, said commutation capacitor being connected between two commutation thyristos of a commutation circuit, one of said commutation circuits being connected between the point common to the anodes of said main thyristors in said switching bridge and the point common to the anodes of said commutation diodes in said commutation bridge, the other of said commutation circuits being connected between the common point of the cathodes of said main thyristors in said switching bridge and the common point of the cathodes of said commutation diodes in said commutation bridge, two of said commutation thyristors in the respective commutation circuits being associated with one terminal of said commutation capacitor and with respective ones of said points common to the n main thyristors for each polarity, and two of said commutation thyristors in the respective commutation circuits being associated with the other terminal of said commutation capacitor and with respective ones of said points common to the n commutation diodes for each polarity.
Dependencies are inferred from the claim text.