A Simplified Space Vector PWM Based on Virtual Carrier Phase Disposition

In order to avoid the complex calculating in multilevel inverters because of coordinate transforming and space vectors choosing, a simplified space vector pulse width modulation algorithm based on virtual carrier phase disposition(VPD-SVPWM) is proposed. This novel algorithm changes a routine of locating and calculating the reference vector in a complicated voltage vector space by decomposing the vector with less dwell times. More importantly, it is general and can be able to applied to any voltage levels of the cascaded H-bridge multilevel inverter directly. In addition, a power balance method is presented to solve the problem of power unevenness among the H-bridge cells caused by the virtual carrier phase disposition. Both simulation and experimental results are provided to demonstrate the algorithm.