A single‐loop and current‐sensorless control for on‐grid seven‐level photovoltaic microinverter

Abstract

Abstract This paper proposes a single‐phase transformerless photovoltaic (PV) microinverter for low and medium‐voltage applications. The proposed approach comprises a suitable combination of multilevel boost/buck and H‐bridge topologies with a current‐sensorless control scheme, where the system controller only needs a straightforward‐to‐implement control loop to reach the desired attributes in solar PV conversion systems. Compared with other microinverters, this proposal significantly reduces the number of hardware components and required software resources, considerably attaining industrial and production advantages; guaranteeing: (i) a high DC elevation factor; (ii) an extraction of maximum power from solar PV panels; (iii) a multilevel output voltage; (iv) a low total harmonic distortion; and (v) a power factor close to unity. The multilevel microinverter's feasibility and effectiveness are assessed by a comprehensive mathematical model, whose simulation results are evaluated using MATLAB‐Simulink, and the experimental results are validated by means of an on‐grid low‐scale prototype, generating a power capacity of 1.5 kW.

Keywords

• DC‐AC power convertors
• photovoltaic power systems