A Novel PWM Scheme with Two Switching Frequencies and Wider Carrier to Improve the THD in Voltage Source Converters

摘要

The integration of renewable energy resources presents a significant set of technical and infrastructure challenges to power grid operation and control. Besides, it has been proven that it is less harmful to the environment. Power electronics technology has the capability to mitigate the effects of the issues imposed on the power system by the rapid expansion of renewable energy development and increased penetration level at the utility scale. Althoughudpower electronics technology is considered a promising potential solution, power conversion efficiency in the rectifiers and inverters must be improved to optimize system performance.udA novel pulse width modulation technique is presented to improve the conversion efficiency. This method has two major concepts. First, widening the on-state of the converter'sudoperation will increase the output fundamental component. Inverse sinusoidal pulse width modulation is one of the methods that can achieve this concept. Second, the rate of change in the information at the peak of the sinusoidal reference is relatively small. The modulation of this period has less significance in comparison to the rest of the reference cycle. Hence, a frequency modulation technique is applied to fulfill this task.udThe novel development and utilization of these two techniques in combination will prove that; in comparison to the sinusoidal pulse width modulation, the fundamental output will increase substantially. Also, this new technique extensively suppresses the harmonic distortion of the converter operation. Furthermore, these results are attained by using lower switching frequency to produce lower switching losses and improves converter operation efficiency.