114 - 23/May/97
SECTION 5 - PRINCIPLES OF OPERATION
5.1 Introduction
In this chapter, principles of operation of the drive system comprising the DBM multiaxes
module and Vickers FAS T and FAS K synchronous motors with permanent magnet
excitation will be described. Theoretical background along with the necessary information
specific for the DBM will be outline, for the purpose of better understanding of the system, for
the aim of a comparison with other systems, and for the ease of the parameter adjustments
during the installation phase. Issues of particular importance are the torque generation,
current control loops and the speed control loop.
5.2 Torque Generation
The DBM is designed for the torque and speed control of synchronous motors with
permanent magnets on the rotor and with the sinusoidal distribution of the stator windings
along the stator circumference. Rather than "trapezoidal EMF" motors with concentrated
stator windings, these motors have sinusoidal electromotive force, induced in the windings
during the rotation of the rotor. Such motors have to be supplied with sinusoidal stator phase
currents. Having these currents shifted by 2
π
/3 relative to each other, and setting the stator
current frequency at
ω
r, the resultant magnetomotive force will be a vector Is rotating at the
rotor speed. The magnetomotive force angle relative to the rotor flux
Ψ
r is marked
θ
i (see
Fig. 1).
Ψ
θ
θ
r
r
i
ω
r
Fig. 1
Is
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