An AC MPPT with Active/Reactive Power Control Feature for Single-Stage Three-Phase Grid-Connected Photovoltaic VSIs

Abstract

This article introduces a new AC MPPT (maximum power point tracking) controller for single-stage three-phase grid-connected photovoltaic (PV) voltage source inverters (VSIs) with active/reactive power control capability. Novelty lies in employing the theory of power transfer in short AC transmission lines to achieve MPPT, where two independent control variables exist: load angle and inverter modulation index. Accordingly, the proposed controller maximizes the capabilities of the single-stage VSI and enables it to control either/both active power or/and reactive power, besides achieving MPPT function. Such contribution opens up avenues in MPPTs world in terms of flexibility, fast performance, and low hardware count/cost. AC refers to Alternate Current since the MPPT is managed in AC terms. Theoretical framework of the proposed controller has been addressed. Moreover, the overall system is simulated in MATLAB (The MathWorks, Natick, Massachusetts, USA) environment, and results have been introduced. Design and implementation of proposed algorithms have been carried out using a fixed-point digital signal processor (DSP)TMS320F2812. Furthermore, a breadboard circuit is built up for experimentally investigating the controller's performance using 3-phase VSI that connects PV with the grid. In addition to that, a comprehensive discussion is conducted for demonstrating results. Moreover, a detailed comparison of proposed work with a number of previously published papers in literature is carried out and addressed in this manuscript. Results reveal that introduced controller achieves satisfactory performance.