System Model and Performance Evaluation of Single-Stage Buck–Boost-Type Manitoba Inverter for PV Applications

Abstract

This article presents a control methodology for a recently proposed single-stage buck–boost-type inverter in photovoltaic (PV) applications. A wide range of input voltage is covered, and the dc power is effectively converted into the grid power within a single-stage system. However, from the topological characteristics, a ${ C\!L}$ filter is always formed at the system output, which results in a resonance pole in the control system. In the PV system, the panel output voltage keeps varying. Under the traditional control method, stability issues may occur, which poses a challenge to controller design. Thus, targeting PV applications, a comprehensive control methodology is presented in this article. Under such a control scheme, a high-quality ac grid power is guaranteed and the power conversion is maintained in a stable manner. Meanwhile, the maximum power point (MPP) of PV panels is always tracked and no additional current sensor is required in the MPP tracking (MPPT) design. In this article, a detailed system analysis is presented, which includes the system modeling and the stability evaluation. The performance of the presented control methodology is experimentally verified in a 750-W PV inverter platform. Both steady state and dynamic characteristics are in good agreement with theoretical knowledge.