Design and controller-in-loop simulations of a low cost two-stage PV-simulator

Abstract

A PV-Simulator is a DC power source in which the current-voltage (I-V) characteristics of different PV arrays can be programmed. With a PV-simulator, the operation of the solar power conditioning systems can be validated at a laboratory level itself before actual field trials. In this work, design, operation and controls for a two-stage programmable PV-simulator required for the testing of solar power conditioning systems are presented. The proposed PV-simulator consists of a three-level T-type active front-end converter in the first stage and a buck-chopper-based DC-DC converter in the second stage. An active front-end rectifier using a three-level T-type IGBT-based converter is used at the input stage to help in operating the system at unity power factor. A DC-DC converter at the output stage of the simulator is regulated to obtain the I-V characteristics of the programmed PV-Array. Hardware-In-Loop simulations are carried out to validate the proposed system and the associated controls implemented in the controller. As a case study, this PV-simulator is programmed with electrical parameters of a selected PV-array and the characteristics obtained from the PV-simulator are compared with the actual PV-array characteristics. The dynamic response of the system for sudden changes in the load and sudden changes in irradiance values are studied.