Hardware-in-the-Loop Experimental Setup of a LCL-Filtered Grid-Connected Inverter with Digital Proportional-Resonant Current Controller

Abstract

This paper presents a Hardware-in-the-Loop setup of a LCL-filtered grid-connected inverter with digital Proportional-Resonant current controller. The power structure of the system, i.e. the power DC source, the transistor-based inverter, the LCL filter, the sensors and the grid are emulated in the Real-Time Simulator HIL402 from Typhoon-HIL, while the control strategy is embedded in the Digital Signal Controller TMS320F28335 from Texas Instruments. Descriptions of how to design the PR controller is presented. Details about the settings of the RTS are also described. The HIL verification consists of applying several real time test cases along the power structure as well as in the control strategy, allowing designers to rapidly evaluate the efficacy of the PR controller. Some modifications are: inclusion of an oscillation at the DC-link voltage, frequency variation at the grid voltage, variation of grid impedance, current reference step, among others. Results show that the HIL verification is an attractive tool for evaluating the PR current controller of a LCL-filtered grid-connected inverter.