Elektrotechnisches Institut (ETI)

A High Current, High Frequency Modular Multiphase Multilevel Converter for Power Hardware-in-the-Loop Emulation

Abstract

This paper presents a simple Modular Multiphase Multilevel Converter (MMPMC) especially for the usage in Power Hardware-in-the-Loop Emulation systems. Standard half-bridges connected to flux compensated chokes are used to build up an inductive voltage divider to form the multilevel voltage waveform. A modulator with a sorting algorithm is employed to calculate the switching signals of the particular branches. The selection of the switching states is depending on the instantaneous branch currents to ensure a symmetrical distribution of the load current to the branches. A modular and scalable converter system has been engineered, which allows the generation of a six level voltage waveform with a PWM-frequency up to 100 kHz. The prototype is controlled by a specifically designed high-performance signal processing system and offers an output current of more than 100 A. Measurements were performed to evaluate the proper functionality of the converter.