Novel Simplified Controller for Three Phase Grid Connected Inverter Based on Instantaneous Complex Power

This paper presents the control of three-phase inverters connected to the grid by using the concepts of the instantaneous abc theory and the effective apparent power Se. These concepts allow the control of the three-phase inverter from a phasorial point of view both in magnitude and phase. The regulation of the instantaneous reactive power Q allows the instantaneous control of the phase delay phi between the grid voltage and the first harmonic of the voltage generated by the three-phase inverter. The calculation of Se allows the instantaneous control of the modulation index m, proportional to the magnitude the inverter voltage. By using these two concepts, it is easy to implement a control of the power flowing to the grid, with variables controlled in DC by means of PI regulators and by using simple calculations. The proposed control is compared with the stationary and synchronous reference frame techniques considering the computing cycles. Simulation results are included to illustrate the effectiveness the proposed control.