A Comprehensive Analysis of a Digital Control Strategy for Photovoltaic-Based Single-Phase Grid-Tied Inverter Systems

This paper generally presents the design procedure of a single phase grid-tied solar inverter and its control system. Moreover, it specifically investigates the behavior of the entire system to obtain its optimal compensators. The power section of the system contains a DC-DC stage followed by an inverter and its filters. Furthermore, the control system includes a maximum power point tracking (MPPT) algorithm, a phase locked loop (PLL), a current controller for shaping the injected current to the grid, and a voltage controller for regulating the voltage of the DC link between the boost converter and the inverter. This paper proposes a featured procedure to simulate the function of each compensator in the Laplace and z-domains, and implement it on a digital microcontroller device. Eventually, the simulation results of a PV-based system comprising a boost converter, a Highly Efficient and Reliable Inverter Concept (HERIC) inverter, and its compensators, operating at 20 kHz switching frequency, are presented.