Transfer of the induction motor to the UPS system after power failure

The stator current and electromagnetic torque transients of induction motor have been investigated in this paper, when the motor is transferred to uninterruptible power supply (UPS). The motor is directly fed by the infinite bus before the power outage, then it is transferred to the UPS system, which consists of two cascaded 3-phase pulse width modulated converters. Both converters are controlled by a single fixed-point digital signal processor (DSP). The computer simulation results of the UPS and motor are obtained from Matlab Simulink models and these results are compared to the experimental ones

Evaluation of reference current extraction methods for DSP implementation in active power filters

Generation of current references constitutes an important part in the control of active power filters (APFs) used in power system, since any inaccuracy in reference currents yields to incorrect compensation. In this paper, harmonic detection methods for generating reference currents have been evaluated on the basis of three-phase balanced and unbalanced load currents processed in the digital signal processor (DSP). The advantages and disadvantages of several methods found in the literature have been discussed on the basis of simulation results. Three of these methods have been programmed in the TMS320F2812 digital signal processor (DSP) unit and their performances are evaluated from the viewpoint of practical considerations. Finally, instantaneous reactive power method to estimate the APF reference currents is implemented and its practical results obtained under balanced and unbalanced loads are given. (C) 2009 Elsevier B.V. All rights reserved