Programmable Multi-input Buck-Boost Converter for Photovoltaics Arrays

TL;DR

The paper addresses the challenge of extracting maximal power from PV arrays under variable weather and mismatches, where conventional buck-boost converters face high switching losses and performance limitations. It proposes a scalable programmable multi-input buck-boost topology built on a two-switch base, with input-side multiplexing switches, panel capacitors, and diodes, plus a boost stage, enabling parallel, cascade, or individual operation. An MPPT scheme combines threshold-based structure switching based on irradiation $I_r$ and temperature $T$, a double-closed-loop PI control, and perturb-and-observe to drive each panel to its $V^*_{PVn}$, ensuring simultaneous MPPT across active panels. Simulation in MATLAB/Simulink validates multiplexing across connection modes and demonstrates wide operating range and reduced switching stress, indicating practical potential for robust PV integration.

Abstract

This paper proposes a programmable multi-input buck-boost structure method, which can enhance the operation tolerance for the PV array under extremely harsh climatic conditions. The proposed structure based on a traditional two switches buck-boost converter can connect PV panels in parallel and cascade flexibly, and also enable the individual operation of each PV panel. The active switches can be programmed to change the connection structures as well as achieve the maximum power point track of PV panels simultaneously. The paper presents the programming method for an exemplified scalable structure converter for two PV panels. The simulation has been established in MATLAB/Simulink to validate the performance of the proposed converter in terms of multiplexing function, wide operating range of PV panels, and low switching stress.

Figures (8)

• Figure 1: Voltage and current behaviors of the PV panels (i.e., Solvis SV36-150, 12 panels in series) under a daily mission profile, where $V_\text{PV}$ and $I_\text{PV}$ are the voltage and current of one PV array under the MPPT operation, respectively.
• Figure 2: Proposed programable concept for multi-input buck-boost converters for PV panels.
• Figure 3: Exemplified two input ports buck-boost converter.
• Figure 4: Connection structures of the proposed multi-input converter exemplified in Fig. \ref{['fig3']}, (a) Parallel connection, (b) Cascade connection, (c) individual PV1 connection, and (d) individual PV2 connection.
• Figure 5: MPPT operation scheme under different connection structures.