(1)
Load current signals are transformed from abc to dq frame
using (1), in which the real and reactive components of the load current
(id and iq ) will have a DC
component ( \(\overline{i_d}\) and \(\overline{i_q}\) ) and an oscillating component (\(\tilde{i_d}\) and \(\tilde{i_q}\) ). The oscillating
component of \(\tilde{i_d}\)is extracted with the help of low pass filter (LPF) and a
subtractor. As complete reactive current ( iq ) and unbalance component (i0)
should be supplied from DSTATCOM, no LPFs are required for q-axisand 0-axis components. The extracted signals are transformed back
to abc frame (i*a, i*b, i*c), which are fed to a current controller for
generation of switching signals for VSC.
2. Reference current generation during VCM operation:The generation of reference signal during phenomenon of voltage
unbalance (VCM operation) is carried out using a novel concept of
single phase SRF theory which can typically be explained as follows: