Versatile Lab VIEW-FPGA-based Testbench for Electromagnetic Interference Evaluation in VSDs

Abstract

This paper demonstrates a testbench system used to assess the conducted EMI measurements of a 3-phase 1 kW Si full bridge DC/AC converter as a variable speed drive (VSD) for 1 HP induction motor under no-load conditions. The control system was developed based on a cyber-physical system composed of a LabVIEW environment and a FPGA-based hardware. The literature review shows that several parameters compromise the inverter's performance using switching modulation techniques for non-linear loads. This paper presents a case study into four of them, namely dead-time, modulation index, modulating frequency and switching frequency. Yet, considering the standards requirements of harmonics control in VSDs, a second case study is also presented for a proposal of evaluating line inductors EMI filters by using the testbench. Therefore, the testbench can be used to improve EMI-based VSD performance and mitigate the conducted emissions by suppressing levels in the source and along the path, thus, ensuring improved electromagnetic compatibility in the system.