| 摘要 |
To provide for fast response of a servo drive with a synchronous machine in which the same torque is available over the entire rotational range of the machine regardless of angular position of the rotor, phase currents to phase windings, preferably three-phase, are controlled in dependence on required torque, and steered to the respective phase windings by a rotor position transducer in such a manner that the sum of all the phase currents remains constant, and is connected to the respective phase windings, in pulses, during an electrical angular range when induced armature counter electromotive force voltages in the respective phase windings, which have an essentially trapezoidal shape, are in their flat or unvarying range within the voltage distribution during revolution of the rotor. Thus, currents are supplied to the phase windings only when the counter EMF voltages are essentially constant. A full-wave bridge-type current supply is suitable, using semiconductor switches, which are suitably controlled to steer currents to the respective phase windings, thus reducing commutating losses since only one of the semiconductor switches is switched ON or OFF, the remaining semiconductor switches functioning only as current steering elements. |
