Analysis and comparison of multicarrier PWM schemes applied in H-bridge cascaded multi-level inverters

Four kinds of compound carrier disposition PWM schemes are discussed, two of which are proposed for the first time in the paper. Methods for analyzing the amplitudes and harmonics of the output voltage of single-phase multi-level cascaded inverter are introduced for these PWM schemes, whose carrier waves could be equivalent to the ones of phase-shifted-PWM. Features of these PWM schemes are summarized and compared utilizing comprehensive and novel indexes, according to a simulation model established in the software PSCAD. Some advices for choosing suitable PWM schemes in practical engineering applications are provided also.