A new approach of continuous waveform modulation

This paper presents a novel continuous waveform modulation (CWM) algorithm for sinusoidal converters, especially for high-voltage variable frequency (HVF) AC power conversion applications. The algorithm is based on multi-level inverter topology. Its major advantages include efficiently reducing total harmonic distortion (THD), improving DC voltage utilization and adjusting the output line voltage smoothly. This paper first introduces the principle of CWM and presents the mathematical expressions of CWM in 5 different working stages. Then, CWM is compared with two other algorithms based on the experimental data derived from the same test platform, a 6 kV/680 kW HVF AC drive system. The field test waveforms of CWM are also illustrated in this paper.