
38-46 Power Electronics and Motor Drives
38.7.6.2 Compensation for These Direct and Indirect Current Techniques
Implemented with the Unipolar PWM Controller
Figure 38.57a and b show the steady-state operation of the SPSAPF with the direct and indirect cur-
rent control techniques implemented with the U-PWM controller. e harmonic spectra of the supply
current aer compensation with direct and indirect current control techniques implemented with the
U-PWM controller are shown in Figure 38.58a and b, respectively. e THD of the supply current is
reduced from 28.5% before compensation to 4.4% aer compensation with the direct current control