Research on harmonic optimal PWM for NPC three-level voltage inverters

Abstract

This paper presents a digital implement method of harmonic optimal pulse width modulation (HOPWM) for the neutral-point clamped (NPC) three-level inverter(TLI), based on digital signal processor (DSP). First, the total stator harmonic current distortion was set as the objective function, harmonic optimal PWM is designed for NPC TLI Second, the optimization toolbox of the matlab software is used to solve the extreme value, with nonlinear constraints of the objective function. Finally, the TMS320F28335 high performance DSP is used to realize the proposed HOPWM for the TLI, and the spectrum of the output phase and line voltage is analyzed. The experimental results indicate the HOPWM can provide good harmonics performance at low switching frequencies.