An Optimization Method for Switch Angle Storage in SHEPWM Modulation

The conventional SPWM (Sinusoidal Pulse Width Modulation) has been widely adopted in power electronics applications primarily due to its hardware-friendly implementation through comparator-based PWM signal generation. Common DSP chips integrate universal PWM generation modules and dead-time modules, offering simple, standardized hardware architectures at low cost. In contrast, SHEPWM (Selective Harmonic Elimination Pulse Width Modulation) employs pre-stored switching angle data for online lookup to generate PWM signals, which fundamentally differs from traditional modulation methods and necessitates dedicated hardware designs. Furthermore, the improved SHEPWM modulation with rapid dynamic updating of switching angles at sampling frequencies―compared to conventional SHEPWM that updates per fundamental cycle―imposes stricter real-time requirements on controller hardware. This paper systematically designs a switching angle storage methodology, analyzes the effects of modulation index step size and switching angle precision on SHEPWM algorithm performance, and significantly reduces memory consumption.