A cascaded doubly-fed induction machine (CDFM) is a connection of two wound
rotor induction machines. In comparison to a single doubly-fed induction m
achine (SDFM) brushes are obsolete. Due to recent developments in brushless
doubly-fed machine design, there is a renewed interest in associated contr
ol. Theoretical and experimental studies of a stator flux oriented control
method for a CDFM are presented, The use of vector control principles to co
ntrol torque, speed, active and reactive power is investigated. It is found
that the additional closed rotor circuit of the CDFM introduces a cross co
upling between the d-axis and the q-axis. Nevertheless, the cross coupling
effect remains small in relation to the overall control concept so that the
control of the CDFM resembles that of the SDFM.