Control of single-phase and three-phase DC/AC converters

In many applications of power converters, an AC voltage with a controllable/variable frequency and voltage amplitude is desired (e.g., in motor-drive applications). By contrast, in the case of grid-connected applications (e.g., photovoltaic systems), the output AC voltage should be «constant» in terms of frequency and amplitude. In all, a power electronic interface is required to link the DC source with the load and to make the output AC voltage compatible in terms of phase, frequency, and amplitude. This power processing is called DC/AC conversion, and the power converters are referred to as DC/AC converters, also known as DC/AC inverters. Depending on the system power ratings, there are typically single- and three-phase DC/AC converters. In order to achieve the above goal (e.g., a constant-voltage and constant-frequency AC voltage), a proper control should be employed. In this chapter, the modeling and control of DC/AC converters are briefly presented in different reference frames (i.e., αβ- and dq-reference frames). The design of commonly employed DC-link and current controllers is in focus with different case studies.