Practical design of the current error trajectory control for PWM AC-drives

A simplified method of predictive current control used for AC motor drives fed by PWM inverters is proposed, which works with a fixed pulse frequency. Starting from a reduced equivalent network describing the stator circuit for a field oriented machine, a linear array of mathematical equations is given to determine the pulse-times of the switched voltage space vectors. The gradients of the current error vector previously determined leave its mark on the parameters of the array just as the initial and final points do. Some variants are compared for the trajectories with regard to the maximum and the RMS-value of the control error. The control principles are modified for the special control ranges including the speed zero and have been used in an industrial drive system with a medium power range.