Digital Variable Frequency Control of a Single-Phase Energy-Buffered Inverter with Multiple Modulation Strategies

In this paper we compare two different approaches to control an inverter operating at variable frequency with multiple operation modes along the line cycle. The first methodology is to control at constant sampling frequency higher than the switching frequency. Over sampling techniques seems promising in reducing the phase lag, but inject high frequency disturbance and may produce limit cycle oscillations. The other approach is to control at variable sampling frequency, equal to the switching frequency. The main drawback is how to discretize the regulator.