High-Frequency Inverter Advanced Digital Modulation Strategy and Implementation Method Considering Dead Time and Switching Transient Effect

Wide bandgap semiconductor devices enable inverters with higher switching and output frequencies. This poses more challenges to obtain high-quality output waveform and control performance. Dead time and switching transients can cause inverter model errors and output waveform distortion, making it difficult to effectively use a model-based high-performance controller. Classical dead-time compensation methods require additional sensing and control loops and are limited in effectiveness at high switching frequencies. Therefore, this article proposes an advanced digital closed-loop modulation for high switching frequency inverters. By introducing the bridge arm output waveform, the effects of dead-time and switching transients and model errors can be eliminated directly in the modulation part without current sensing or additional control loops, and can operate at high switching frequencies. In addition, the proposed modulation method has high integrability, flexibility, and scalability. The theoretical analysis is verified by illustrative simulation and experimentally validated examples using a 1-kVA laboratory prototype with a 1000-Hz fundamental frequency.