Modeling, Design and Control of a Solar Array Simulator Based on Two-Stage Converters

Abstract

Power inverters for photovoltaic (PV) applications must be tested according to standards in order to be certified and commercialized. A common practice to test PV inverters is the utilization of solar array simulators (SAS). This paper presents a SAS topology based on a double-stage structure: The first stage is based on a three-phase PWM rectifier, and the second stage is based on a bidirectional buck converter. This structure is responsible to emulate the photovoltaic array behavior. A methodology to design the SAS components and control system parameters is presented. This methodology considers a range of operation points of the SAS. Additionally, it is verified that the dc-link capacitance of the inverter under test can affect the SAS dynamic behavior and its output current ripple. The results are divided into two parts: resistive loads and commercial inverters. Firstly, the SAS steady-state operation following the solar array I–V curve is demonstrated through simulation and experimental results, using resistive loads. In the second part, two commercial inverters with different nominal power and dc-link capacitance are considered. Using the proposed design methodology, the SAS topology operates correctly and the maximum power point tracker of the inverter under test is not affected if its input capacitance is within the design limits.