Time domain simulation has been carried out to verify
the results predicted earlier. Fig. 11 shows the waveforms of
the voltage, vo, across Cf and the current, if, in the filter
inductor Lf. Initially, the drive power is zero when the boost
converter starts up. The drive power is gradually increased to
7 Nm at t = 0.6 seconds and this power is maintained until t =
2.0 seconds when a step increase in power takes place. As
seen, both voltage and current of the filter start to diverge
and hence system becomes unstable. This result coincides
with the unstable condition predicted in Fig. 8.