A New Nested Neutral Point-Clamped (NNPC) Converter for Medium-Voltage (MV) Power Conversion

Abstract

In this paper, a new voltage source converter for medium voltage applications is presented which can operate over a wide range of voltages (2.4–7.2 kV) without the need for connecting the power semiconductor in series. The operation of the proposed converter is studied and analyzed. In order to control the proposed converter, a space-vector modulation (SVM) strategy with redun- dant switching states has been proposed. SVM usually has redun- dant switching state anyways. What is the main point we are trying to get to? These redundant switching states help to control the out- put voltage and balance voltages of the flying capacitors in the proposed converter. The performance of the converter under dif- ferent operating conditions is investigated in MATLAB/Simulink environment. The feasibility of the proposed converter is evaluated experimentally on a 5-kVA prototype.