Hybrid Multi-Segment SVPWM with Simplified Implementation for Single-Phase Three-Level Converter

Single-phase converters are being widely used in new power systems, and in order to output high-quality voltage waveforms in power systems, multilevel converters are well known solutions. However, the high harmonics caused by the modulation strategy will seriously deteriorate the power quality. In this paper, the modulation strategy of single-phase three-level converter will be deeply discussed and investigated in order to solve the problems of poor harmonic performance of the converter and the balance of neutral point voltage. Firstly, the new hybrid SVPWM algorithm with more segments is analyzed to ensure that the algorithm can achieve the balance of neutral point voltage and good harmonic performance. Secondly, a one-dimensional space-vector modulation strategy is introduced into the algorithm, which is based on geometrical computation and has a simple calculation method with high versatility. Finally, through simulation and experiment, it is verified that the hybrid SVPWM algorithm with more segments under the one-dimensional space vector modulation strategy can not only improve the harmonic performance and realize the ability to balance neutral point voltage, but also simplify the modulation calculation process and improve the operation efficiency.