Performance evaluation of three-phase induction motor under different ac voltage control strategies' Part I'

In this paper three voltage control, strategies for three- phase AC voltage regulator have been studied. These strategies depend on varying the stator ac voltage to control the speed of three-phase induction motor. These strategies are phase angle control (PAC), extinction angle control (EAC), and modified phase angle control (MPAC). The first control strategy is carried out using three back-to-back thyristors connected in series with motor terminals. The other two techniques are used with converter having six bidirectional switches. Performance evaluation of the motor under these switching techniques is shown. Simulation of the system is carried out by PSIM computer program. The simulation results show stable operation for wide range of speed control. The level of harmonics in the supply currents and power factor have been also evaluated for different control strategies.