IEEE Workshop on Wide Bandgap Power Devices and Applications in Asia (WiPDA Asia 2018)

357 / 2017-12-10 01:12:19

Variable Switching Frequency PWM for Three-Level NPC Converter Based on Peak Prediction of Current Ripple

Plenary track > Common-mode and EMI management

Three-level Neutral-Point-Clamped (NPC) converters with pulse width modulation (PWM) strategy converters are one of the most widely used multi-level converters.Totally, constant switching frequency PWM and variable switching frequency PWM are the two most commonly used PWM strategies. Among them, variable switching frequency PWM(VSFPWM) can achieve better current performance due to the freedom of switching frequency. In this paper, the current ripple of three-level NPC converters is analyzed based on circuit davina equivalent principle and the current ripple analytical expression of three-level NPC converters corresponding to 27 different voltage vectors is obtained. Based on theoretical analysis, a novel VSFPWM strategy with THD optimization of output current is proposed by setting the current ripple peak within a certain value. At last, the correctness of the theory in this paper is verified by simulation results.