Model predictive decoupled power control for single-phase grid-tied inverter

Control of ac power in a grid-tied inverter often involves synchronous reference frame transformation, a process which requires phase-angle information typically provided by a Phase-Looked Loop (PLL). This paper presents a decoupled real and reactive power control technique, for a single phase grid-tied inverter, using Model Predictive Control (MPC). The proposed technique does not use a PLL, PWM nor a synchronization transform, which makes the control algorithm well suited for an all-digital implementation. This paper explores the proposed controller performance under distorted grid conditions and variations of system parameters. The results show that the proposed controller keeps good power tracking performance with small error in steady state and the grid side current Total Harmonic Distortion (THD) is within the IEEE-519 standards limits, which allows a much smaller dc-link capacitor to improve system´s reliability and power density. The dynamic performance and steady state stability of the proposed predictive controller are evaluated in this paper. The tracking performance of the proposed controller is compared to the conventional PLL-based method, the result demonstrate significant improvement in the steady state power tracking error when using the proposed controller. The simulation result is validated by implementing the control algorithm experimentally using dSPACE 1007.