Fig. 2.6(a) and Fig. 2.6(e), it can be noticed that, at every moment that the carrier wave reaches its peak
value the phase current, iB, is equal to its average value, in this case 0A. Due to the principle of the PWM
the voltage reference is constant over one switching period . Due to this fact, the controller can not control
the current in the switching period, it can only control the average value of the current. This means that the
control system sets the average voltage for one switching period to control the average value of the current.
To measure the average value of the current for the feedback to the control system it is important that the
measurement is synchronized with the current wave peaks. The current samples must be taken on the peaks
of the carrier wave in order to set the average value of the current.