Implementing continuous and discontinuous space-vector pulse-width modulation using carrier based approach for diode-clamped multilevel DC-AC converters

摘要

Various pulse-width modulation (PWM) strategies have been proposed for multi-level converters so far. These modulation strategies are typically either Space-vector based implemented or Carrier-based implemented. Carrier-based PWM offers less computational complexity and ease of operation in comparison with the classical space-vector PWM. Conventional space-vector PWM keeps dwell times of redundant states equal which reduces the Total harmonic distortion (THD) significantly. A general method to calculate the CM offset to implement the SVPWM using carrier-based approach is derived in this paper. Also, a generalized expression for the CM offset with varying weightage to the redundant switching states has been derived. Further, this modulation strategy has been extended to Discontinuous mode operation. Proposed approach has been simulated and the results are in agreement with that of Space-vector PWM.