PERFORMANCE IMPROVEMENTS IN STATOR FLUX ORIENTED INDUCTION MOTOR DRIVES

This paper describes a scheme for stator flux oriented control of 3-phase induction machine using PWM(Pulse Width Modulation) inverters. The instantaneous values of the flux and torque, which are calculated from the primary variables, are controlled directly and independently by selecting optimum output voltage vector, so as to attain fast torque response, low inverter switching frequency and low harmonic losses. In steady state operation, the amplitude of stator flux is controlled to obtain the maximum efficiency. And dead time for power device protection is also compensated with modifing stator flux calculation. DSP(Digital Signal Processor) was employed for instantaneous calculation of the flux and torque, and IGBT(Insulated Gate Bipolar Transistor) was used for the high frequency switching. Software simulation and experiment are carried out to show the excellent characteristics for torque response and efficiency improvements.