Nowadays, Digital Sinusoidal PWMs are playing a major role in the generation of pure sinusoidal waveforms using micro-controller based inverters. The types of DSPWMs that can be generated depend on the micro-controller hardware resources and are therefore limited, but provide performance benefits not possible with an analogue controller. For instance, digital controllers offer a programmable solution and therefore more flexibility, as advanced algorithms and additional features can be added to the system in software instead of hardware. Digital controllers are also less sensitive to environmental conditions and show precise behaviour compared to their analogue counterparts. In this paper,  the theory of the three major DSPWMs are presented, including mathematical models and simulation results. The PWM patterns required to generate these DSPWMs and the benefits and limitations of each are examined.