Generalized Multicarrier PWM Technique for Two-Level Voltage Source Inverters

Two-level voltage source inverters are the mainstream solution for many power applications. The conventional modulation method of such inverters is the single-carrier pulsewidth modulation (PWM) technique. In this article, the usage of a generalized PWM method with three independent carriers is analyzed. The carrier phase-displacement angles are evaluated in order to reduce the common-mode voltage (CMV) total harmonic distortion (THD), the dc-link capacitor current THD, and the phase currents THD. These targets are difficult to be met at the same time and a cost function is deployed in order to look for a suitable solution that develops a tradeoff between all the targets. The proposed method has been tested in a laboratory prototype demonstrating its superior performance.