Two Phase Motor under Control

Abstract

The use of symmetrical two-phase stator windings with time phase control, (leaving the phase voltages eqal in magnitudes), leads to better utilization of machine material. This aidea can be extended to include many methods of control such as amplitude control, time-phase control, frequency control, voltage control and voltage-frequency control methods. If any of these methods is used, either Vc, , f and/or Vr may be varied with the control signal. For these sugested methods, the reference voltage Vr, changes w.r.t nominal voltage Vrn, the frequency changes w.r.t the nominal frequency fn, the control voltage Vc, changes w.r.t nominal voltage Vrn and the time phase angle  decreases than 90o, respectively. In this paper, the operation of 2-phase motor from single-phase supply is carried out by connecting one stator phase directly to the voltage source, and exciting the second stator phase through a phase shifting element.Compared to single-phase operation, good performance characteristics with higher starting torque are achieved. It is necessary to start the analysis by using the known equivalent circuits of both forward and backward components to obtain the relations between the sequence parameters and the phase values. In this method of control, starting torque and maximum torque values are controlled by changing the stator field from a pulsating field at zero degree to a pure rotating field which must be achieved at 90o electrical degrees.