Decoupled Modulation Strategy for Harmonic Current Suppression in Five-Phase Series-End Winding PMSM Drives

In order to improve the linear modulation region in the control, the series-end winding (SW) is applied in the drive of five-phase permanent magnet synchronous motors. However, this drive topology will lead to a zero-sequence loop, so the zero-sequence back electromotive force will produce a zero-sequence current (ZSC). This letter proposes a decoupled modulation strategy for harmonic current suppression, including the ZSC. At first, all the space voltage vectors in the several subspaces have to be obtained. Virtual voltage vectors, which only contain the
α–β
or
x–y
components, are calculated and applied in the space vector modulation strategy. In this way, the current in different subspaces can be controlled separately. Then, the modulation in the zero-sequence subspace is decoupled from the
α–β
and
x–y
subspaces through the duty cycle compensation. The reference zero-sequence voltage (ZSV) is obtained by adjusting the duty cycle of each drive leg. The ZSC is suppressed after the ZSV is injected. In the experimental validation, the harmonic current in the
x–y
subspace and ZSC are reduced greatly to 61% and 59%, respectively.