Multi-phase machines and drives is a topic of growing relevance in recent years, and it presents many challenging issues that still need further research. This is the case of multi-phase space vector pulse width modulation (SVPWM), which shows not only more space vectors than the standard three-phase case, but also new subspaces where the space vectors are mapped. Different approaches have been recently followed, and the aim of this paper is to review and classify these methods. Comparative results are included to highlight the weak and strong points of the different methods. Finally some conclusions are extracted pointing out the problems that still need to be solved.