Study on Active Resistance Design Methods for Digital Current Controllers of IPMSM

To enhance the capability of rejection capability of the back EMF disturbance, active resistance technique is commonly used. In regard to the current values used to implement the active resistance, normally there are two ways, using the present sampled current or using its one-step prediction value. Analysis about the difference between the two typical methods however, has not been found up to date. To fill the gap and to make some theoretical guidance for selection of these two ways, the differences are analyzed carefully and some suggestions are presented to engineers. After that, some potential weaknesses of the two methods are discussed and the possible ways to developing them further are presented. What's more, the analysis is taken in the discrete-time domain directly and suitable for the condition of low carrier ratio. At last, all of the analyses are verified through experiments.