Dynamic investigation of capacitors voltage of flying capacitor multilevel inverter based on sine-sawtooth PSCPWM

In this paper the dynamic of capacitors voltage of flying capacitor multilevel inverter (FCMI) based on sine-sawtooth phase shift carrier pulse width modulation (PSCPWM) is investigated. By using the double Fourier series of PWM, the double Fourier series of PSCPWM is achieved. In continuous by applying the double Fourier series of sine-sawtooth PSCPWM, the linear state space equations of capacitors voltage of FCMI are obtained. The result is presented as a state space matrix. The presented method of this paper allows that the changes of parameters such as modulation index, carrier frequency, load resistance and load inductance be analyzed and investigated by using powerful strategies such as root-locus. By simulation of FCMI operation in PSCAD/EMTDC software, the validity of theoretical analysis is proved.