Electromagnetic Compatibility–Driven Design and Real-Time Control of Multilevel Inverters for Conducted EMI Reduction

Abstract

Multilevel inverters (MLIs), as a robust solution, have gained popularity for medium and high-power applications owing to its excellent quality of output waveforms, higher efficiency performance, lower switching stress and superior scalability over conventional two-level converters. The increasing use of these types of circuits by the implementation in renewable power systems, electric vehicles, smart grids, industrial motor drives and energy storage systems means electromagnetic compatibility (EMC) has become a significant issue for the design of most power electronics nowadays. Multilevel inverters are using high frequency causes to radiate EMI, but also the switching operation at multi-level inverter creates a major conducted EMI sources due to rapid voltage transitions, parasitic coupling effects and common-mode voltage generation. These disturbances can impair system reliability, reduce communication and sensing performance, and make compliance with international EMC standards more difficult.

Traditional EMI mitigation methods are largely based on passive filters or shielding structures, requiring modifications with changes to the grounding and direct re-design of hardware that add cost, size, weight and power losses in addition to leading to an after-the-fact manner of addressing EMI once converters have been developed. The above-mentioned methods are losing significance in modern power electronic systems which have higher switching frequencies, lower inductances and wide-bandgap semiconductors utilized. Therefore, this has led to the need for design approaches where EMC is integrated into inverter compensation and operation as part of control methodology rather than post-design compliance.

This paper presents an Electromagnetic Compatibility–Driven Design and Real-Time Control Framework for multilevel inverters to minimize conducted EMI at the source while preserving high-performance converter operation. The proposed methodology is a combination of inverter modelling, modulation strategy selection, switching-state control and real-time implementation in order to incorporate EMC requirements. To support controller design and performance analysis, a detailed inverter model including switching dynamics, parasitic components, common-mode behavior and conducted EMI propagation mechanisms is developed. Advanced EMC-aware control methods are used for conducted emission suppression, common-mode voltage and current reduction, power quality increase, and compliance with international EMC regulations.

To assess practicality under realistic operating conditions, the proposed framework has been implemented on real-time control platforms such as Digital Signal Processors (DSPs) and Field Programmable Gate Arrays(FPGAs). The EMI measurements involve harmonic analysis, efficiency evaluation, common-mode behavior characterization and comparison against CISPR and IEC standards. The results show that, by integrating EMC considerations directly into controller design, it is possible to achieve significant source level EMI reduction without performance loss in the dynamic and power quality domain. The framework proposed in this study offers a practical and scalable approach to the development of next-generation EMC-compliant multilevel inverter systems for industrial, transportation, and renewable power generation applications.