a technique for reconstructing phase currents based on measurements of a dc bus current . non - observable regions of dc bus current samples to reconstruct phase currents are reduced in size by using two phase space vector modulation . the non - observable regions can be further reduced by omitting deadtime insertions for switch actuations when output current is higher than a given threshold . voltage command vectors in non - observable areas can be constructed by two time averaged vectors one of which is constructed to obtain an observable dc bus current reflecting motor phase current . the additive vectors have the same combined time average value as that of the voltage command vector in order to preserve volt - seconds . current samples may also be averaged to provide a more accurate reconstruction of phase current . current samples are time delayed to avoid transients for more accurate readings . when three phase pwm inverter modulation results in inability to determine the motor phase current from the dc bus measurement , the technique includes dynamically switching to two phase pwm modulation to reduce the time interval when the motor phase current is not determinable through the dc bus current measurement .