Comparisons of real time generated space vector modulated signals for motor drive applications

This paper compares and analyses different methods of implementing the direct flux space vector modulation (DFSVM) algorithm for inverters. It highlights the advantages of such a scheme in overcoming the limitations of the conventional PWM strategy. The key benefits claimed are: 100% utilisation of the DC link voltage, as compared with only 86.6% utilisation for PWM case; 33.3% reduction in switching losses for a given switching frequency, as compared with PWM method; potential size/value reduction in the DC link capacitor, as the control scheme accommodates variation of DC link voltage during transient and steady-state conditions; reduced transient current at start-up, and faster convergence to steady-state conditions; and reduced harmonic distortion in the current, hence a reduction in harmonic losses and torque ripple. The space vector modulated signals are generated in real time using a Siemens C167 microcontroller, and the signals are used to drive an inverter supplying a fractional horsepower (750 W) three phase AC induction motor load for experimental tests. Simulation and experimental results are shown to be favourable