Latest revision as of 10:53, 4 May 2026

Abstract

Multilevel inverters (MLIs) offer superior waveform quality, reduced harmonic distortion, and lower voltage stress compared to conventional twolevel converters. In such systems, the individual voltage levels are typically generated through DC-DC converters, where each level is produced for a specific duration by selectively connecting one or more DC sources. To generate lower voltage levels, some DC sources are temporarily disconnected, resulting in light-load or no-load conditions making the output of the DC-DC converters unstable. Most existing control strategies for DC-DC converters are designed to regulate the output voltage assuming a continuously connected load, which leads to instability when the converter operates at light or no-load conditions. To address this challenge, this paper employs a Constant Voltage Constant Current (CVCC) control method to ensure stable voltage generation for MLI voltage levels. The proposed method is benchmarked against Proportional–Integral (PI), Fuzzy Logic (FL), and Sliding Mode Control (SMC) techniques. Simulation results demonstrate that the proposed method achieves superior voltage stability, accuracy, and transient performance. The proposed method is used to generate three-level and seven-level voltage waveforms in the PLECS environment, and its real-time implementation further validates its effectiveness and practical applicability. The results confirm excellent voltage regulation, with capacitor voltage fluctuations remaining below 1 V (corresponding to only 0.33% of the nominal 300 V DC-link voltage, compared to the commonly accepted±5% tolerance).OPEN ACCESS Received: 06/12/2025 Accepted: 05/03/2026

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