Title :
Control of a Single-Switch Two-Input Buck Converter for MPPT of Two PV Strings
Author :
Urtasun, Andoni ; Lu, Dylan Dah-Chuan
Author_Institution :
Dept. of Electr. & Electron. Eng., Public Univ. of Navarra, Pamplona, Spain
Abstract :
In this paper, the two-input buck converter is proposed as the dc/dc stage for photovoltaic (PV) cascaded converters. This converter is attractive for this application because it is cost effective and reliable and can achieve dual maximum power point tracking (MPPT) with only one power transistor. However, due to the simplified and integrated structure, the nonlinear characteristics of the converter and the two PV arrays complicate the control. By means of a small-signal modeling, the control theme of the two PV voltages is formulated, and the effect of the nonlinearities is presented. It is shown that, while fast voltage dynamics are achieved for the first input, the second-input voltage response depends on the second-stage converter control. Simulation and experimental results are reported to validate the theoretical analysis, showing the dual MPPT capability.
Keywords :
DC-DC power convertors; control nonlinearities; maximum power point trackers; nonlinear control systems; photovoltaic power systems; power generation control; voltage control; DC-DC stage; PV arrays; PV strings; dual MPPT capability; dual maximum power point tracking; fast voltage dynamics; nonlinear characteristics; photovoltaic cascaded converters; second-input voltage response; second-stage converter control; single-switch two-input buck converter control; Capacitors; Inductors; Inverters; Maximum power point trackers; Resistance; Switches; Voltage control; Dual MPPT; Dual maximum power point tracking (MPPT); Photovoltaic power systems; Small-signal modeling; Two-input converters; Voltage control; photovoltaic (PV) power systems; small-signal modeling; two-input converters; voltage control;
Journal_Title :
Industrial Electronics, IEEE Transactions on
DOI :
10.1109/TIE.2015.2432097
