Study On The Three-level NPC Inverter Based On The SPWM

As with the development of society and economy, the power electronic technologygets the opportunity to evolve. And for the high power application situation, the multi-levelconverters offer a good method to solve the problem. Because of the simple topology andcontrol, the Neutral-Point-Clamped three-level inverter become the mostly used converter.Base on the NPC three-level inverter, this article gives a detailed introduction about themodulation, the fluctuation of neutral voltage, the design of main circuit and snubbercircuit.First of all, the article introduce the development of multi-level converters, and thenanalyse the bond of two modulation technology SPWM and SVPWM. Because of theconvenience of SPWM, this article discusses two conventional ways to solve the neutralvoltage fluctuation, based on the SPWM. And after that, a new method is provided basedon the two conventional ways, which is easy to implement and can lower the switchinglosses. These methods are verified by simulation and experiment. At last, the article givethe design principle of the main circuit and snubber circuit, especially the snubber circuit.