Experimental Validation of Three-Level Advanced-Active-Neutral-Point-Clamped Converter for Grid Operation

The three-level Advanced-Active-Neutral-Point-Clamped converter (AANPC converter) represents a multilevel converter with a fault-tolerant behaviour. Furthermore, it has a high degree of modularity as the configuration is based on the use of low-inductive standard components. This aspect can be advantageous for the next generation power semiconductor modules. This paper focusses on the implementation of the Software structure for generating the switching signals in an FPGA and implementing a control routine in a muC. The control of the converter mainly comprises DC-link voltage control with subordinate current control loops. The synchronisation with the grid is performed using a phaselocked loop (PLL). During implementation, both a bidirectional power flow and the redundant operation as a twolevel converter are considered. Furthermore, experimental validation of a demonstrator of AANPC converter for grid operation at safety extra-low voltage is presented.