Look-up Table Size Reduction Strategy for Synchronous Optimal Pulse Width Modulation

Synchronous optimal pulse width modulation (SOPWM) offers low current total harmonic distortion (THD) at lower switching-to-fundamental frequency ratios. However, the SOPWM method requires a large amount of memory space from the microcontroller to achieve its best performance due to high-resolution pre-optimized optimal switching angles (OSAs), which is one of the major drawbacks of the SOPWM method. To address this drawback, this paper proposes a new strategy to reduce the look-up table size of OSAs in the SOPWM by generating new switching angles with few points from the original OSAs while ensuring the new switching angles error under desired range. The influence of optimal switching angle error on the voltage, current THD performance, and modulation index are also presented. Experimental and simulation results are provided to demonstrate the effectiveness of the proposed method.