DSP-based stable control loops design for a single stage inverter

The design of stable DSP-based controller for a new single stage inverter architecture with solar energy input is discussed in this paper. The proposed architecture uses two dependent control loops to track the maximum available power of a solar array source, and to supply a sinusoidal current to the utility grid. If not well designed, the control loops in this inverter configuration suffer from instability when operating at different regions of the solar array power curve, namely the Right Hand Side region (RHS) and the Left Hand Side region (LHS). This paper presents a mathematical analysis to the source of instability, and proposes a robust controller for stable system design. Experimental results are presented to verify the validity of the designed controller.