Basic characteristics and control method of a new five level inverter with adjustable mid-level voltage

This paper describes the basic characteristics and PWM control method of a new five-level inverter with adjustable mid-level voltage for adjustable voltage adjustable frequency (AVAF) inverter systems. The strategy is based on a symmetric uniform area sampling PWM technique achieved with a digital signal processor (DSP) and logic circuits. The scheme can decrease that voltage deviation in the output waveform which is caused by the potential variations of the levels, and reduce the switching losses by using two arms modulation. The resulting maximum peak line-to-line voltage is approximately equal to the DC source voltage. The experimental results demonstrate the validity of the proposed method. This paper also illustrates the performance of the proposed inverter in adjusting the magnitude of the mid-level voltage