Nonlinearity analysis and linear modulation method for two level voltage source inverter with low switching to operating frequency ratio

Recently, high speed motor drive is widely studied thanks to its advantages such as high reliability and power density. In these applications, the ratio of switching to operating frequency, Fratio, becomes very low due to the limitation of the switching frequency of switching devices. Such a low Fratio drive is also discussed in traction and high power applications due to the efficiency issue. Among the various issues regarding the system with low Fratio, this paper analyzes the nonlinearity in modulation caused by vector rotating direction of space vector modulation. This paper also presents the correcting method for linear modulation. Simulations and experiments with reactor are accomplished to verify the analysis and compensation method for inverter with low Fratio.