A Mathematical Model for Wound Field Switched Flux Machine Considering Inductance Harmonics of Field and Armature Windings

A mathematical model of the wound field switched flux (WFSF) machine considering inductance harmonics is proposed in this paper, including harmonics of the DC winding self-inductance
L_f
, and those of mutual inductance
M_fx
(
x
= A, B, C) between
x
-phase armature winding and the DC winding, which can predict the DC winding induced voltage of the WFSF machine. The modelling method decouples differential terms
di_d
/
dt
,
di_q
/
dt
and
di_f
/
dt
of
d
-axis current
i_d
,
q
-axis current
i_q
and DC winding current
i_f
in
d
-,
q
-axis voltage equations and the DC winding terminal voltage equation. The simulation of the control system with the proposed mathematical model is conducted and compared with the field-circuit coupling co-simulation to verify the proposed mathematical model, which shows its advantage of less time consumption. The proposed mathematical model is further compared with experiments, which validates the accuracy of the modelling method, as well as the capability to predict the DC winding induced voltage pulsation.