Digital control based on the shifting phase for grid connected photovoltaic inverter

In photovoltaic (PV) system connected to the grid, the main goal is to control the power energy that inverter inject into the grid, from the energy provided by photovoltaic generator. The characteristics of the power grid vary depending on the load; therefore injecting power does not only include the control of injecting active power, but the control of the reactive power is necessary. In this paper, the new digital control strategy, based on the shifting phase of the inverter output voltage related to the grid voltage in order to control both, the inverter output current and the power factor with a minimum SPWM pattern. The proposed control strategy is simple and required a relatively low hardware and computational resources, reason why become in attractive solution for low power applications (for example house applications). In this paper are presented the main key point of propose strategy and discussed with simulation and experimental results provided for different design conditions.