Enhancing Output Smoothness in AC-AC Converters: THDv Reduction with Bidirectional Exclusive Switches

The AC-AC converter is a device commonly used in the industrial sector today due to its ability to convert AC power at high frequencies. However, despite its widespread use, the AC-AC converter faces challenges in providing a smooth output. A major issue is the high Total Harmonic Distortion in voltage (THDv) at the output, which negatively affects system performance. This study proposes an improved solution by replacing the Silicon-Controlled Rectifiers (SCRs) with two bidirectional exclusive switches. These switches offer better controllability, faster response times, and lower switching losses compared to SCRs. When integrated into the AC-AC converter topology, they lead to a significant reduction in THDv, achieving 0.96% for a duty cycle of 30% under single-stage DC modulation, and 2.28% for the same duty cycle under double-stage DC modulation. Both modifications result in a smoother output waveform.