Lennart Baruschka

Learn More
A new ac/ac modular multilevel topology for connecting two three-phase systems is introduced. The operating principle is explained, and characteristic waveforms are given. It is shown that the converter system offers superior performance for applications like low-frequency wind turbines. The analytic results are verified by a laboratory setup.
In this paper, a novel 3-phase AC/AC modular multilevel converter is presented and analyzed. Characteristic diagrams obtained from an analytic simulation model are shown in order to discuss the circuit's properties and how it can be used to advantage. The converter is compared to the M<sup>2</sup>LC in back-to-back configuration as a reference topology.(More)
The recently proposed modular multilevel converter &#x201C;Hexverter&#x201D; offers many advantages in high-voltage and high-power applications. This paper presents an improved Hexverter topology by introducing magnetically coupled branch inductors. These lead to a simplified system behaviour and a reduced amount of material for the branch inductors.
This paper presents a hybrid converter for offshore HVDC applications, consisting of diode rectifiers and a Modular Multilevel Converter. The main task of the Modular Multilevel Converter is to support the wind park with auxiliary power during low wind speed periods, thus avoiding an extra AC cable for auxiliary power. Using the Modular Multilevel Converter(More)
With the rising demand for energy harvesting from regenerative power sources, increasing power and voltage ratings are required of power electronic converter systems. For high-power conversion systems, modular multilevel converters proved to be superior to conventional topologies. This paper introduces a reduced variant of the well-known modular multilevel(More)
In order to stabilize the grid frequency in case of sudden loss of power generation, an injection of real power is needed. For this, a Static Var Compensator (SVC) can be combined with ultracapacitors, forming a grid frequency stabilizer. To prove the feasibility of this novel combination, the paper shows the realization of a 1 MW class test rig for(More)
This paper presents a hybrid modular multilevel topology for medium voltage drives requiring low frequencies and a high start-up torque. It operates from a DC supply which makes it easy to connect several drives to a single active front end converter, optionally also enabling galvanic isolation. The topology is compared to the modular multilevel matrix(More)
In this paper, branch energy balancing as part of a generalised control concept for modular multilevel converter topologies is investigated. A way to derive an optimal branch energy balancing regarding current stress is introduced. Afterwards, this generalised approach is applied to the Modular Multilevel Converter as an example topology. The approach is(More)
  • 1