Four quadrant control circuit for a brushless three-phase dc motor
Abstract
A control circuit is provided for a brushless three-phase dc motor which affords four quadrant control from a single command. The control circuit probes acceleration of the motor in both clockwise and counterclockwise directions and braking and generation in both clockwise and counterclockwise directions. In addition to turning on individual transistors of the transistor pairs connected to the phase windings of the motor for 120 deg periods while the other transistor of that pair is off, the control circuit also provides, in a future mode of operation, turning the two transistors of each pair on and off alternately at a phase modulation frequency during such a 120 deg period. A feedback signal is derived which is proportional to the motor current and which has a polarity consistent with the command signal, such that negative feedback results.
- Publication:
-
NASA Marshall Space Flight Center Report
- Pub Date:
- February 1987
- Bibcode:
- 1987msfc.reptQ....N
- Keywords:
-
- Direct Current;
- Electric Current;
- Electric Motors;
- Electric Switches;
- Switching Circuits;
- Transistors;
- Negative Feedback;
- Patents;
- Phase Shift Circuits;
- Tethered Satellites;
- Waveforms;
- Electronics and Electrical Engineering