Loss-oriented asymmetrical PWM technique for high-frequency impedance source converters

The paper presents four asymmetrical pulse width modulation techniques for three-phase impedance source converters operating at high switching frequencies. The concept behind all proposed methods is to introduce single-phase shoot-trough states and reduce commutation currents of fast-switching SiC MOSFETs. All techniques are explained and verified by means of Saber simulations and laboratory experiments. Advantages and negative aspects, such as increased on-state losses, are discussed in reference to state-of-the-art techniques. Performed measurements at 100kHz/6kVA model of the quasi-Z-source inverter show that in selected operation areas new techniques lead to slightly improved efficiency without loss of input and output currents quality.