Brushless ultra-efficient regenerative servomechanism
A servomechanism regeneratively controls motion by a brushless coreless axial-field motor, exerting torque thru its permanent-magnet disk rotor, resulting from synchronized polyphase sinusoidal stator currents, controlled by a switching controller responsive to input commands and to Hall-effect transducer signals that vary sinusoidally with rotor angle and respectively correspond to stator phases. The controller operates with a dc power source and sink. Its signal processors derive from the transducer signals instantaneous magnitudes and polarities thereof and continuous lagless speed feedback. The instantaneous magnitudes are multiplied by a torque amplitude signal to provide respective synchronized amplitude control signals. Current transformers having primary windings in series with power switching transistors provide current feedback pulses with amplitude proportional to instaneous current in associated stator windings. Pulse control means initiate bi-phase pulses having restricted duty-cycle, and dictate pulse duration by comparing each current feedback pulse with the associated synchronized amplitude control signal. Switching logic responsive to the bi-phase pulses, to forward and reverse drive and brake commands, and to said polarities, accordingly controls selection and duty-cycle of said power switching transistors which, cooperative with free-wheeling diodes and inductors, effect controlled alternating stator currents.
- Assignee:
- EDB-86-015847
- Patent Number(s):
- US 4520300
- OSTI ID:
- 6280914
- Resource Relation:
- Patent File Date: Filed date 6 Dec 1982; Other Information: PAT-APPL-433170
- Country of Publication:
- United States
- Language:
- English
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