PROJECT TITLE :

A Capacitor Voltage-Balancing Method for NestedNeutral Point Clamped (NNPC) Inverter - 2016

ABSTRACT:

A capacitor voltage-balancing method for a nested neutral point clamped (NNPC) inverter is proposed during this paper. The NNPC inverter is a newly developed four-level voltage-source inverter for medium-voltage applications with properties like operating over a wide selection of voltages (2.4-seven.a pair of kV) without the need for connecting power semiconductor in series and high-quality output voltage. The NNPC topology has 2 flying capacitors in each leg. In order to make sure that the inverter can operate normally and all switching devices share identical voltage stress, the voltage across each capacitor ought to be controlled and maintained at one-third of dc bus voltage. The proposed capacitor voltage-balancing method takes advantage of redundancy in phase switching states to regulate and balance flying capacitor voltages. Straightforward and effective logic tables are developed for the balancing management. The proposed technique is easy to implement and needs very few computations. Moreover, the tactic is suitable for and straightforward to integrate with different pulse width modulation schemes. The effectiveness and feasibility of the proposed method is verified by simulation and experiment.