Herbert Gambach

Comparison of multisystem traction converters for high-power locomotives

The European railways are characterized by a wide range of supply voltage systems. To allow flexible operation of electrical locomotives and short stops at system borders, multisystem locomotives are necessary. The paper gives a comparison of different solutions for multisystem converters and introduces the most promising concept based on the latest high-power IGBT technology.

Modular multilevel converter with short-time power intensive electrical energy storage capability

The developing political and environmental reforms are driving a fast change in the energy mix of many nations. The increasing electrical energy being fed from renewable energy sources (e.g. wind and photovoltaic) impacts the dynamic behaviour of the power grid. Phasing out of existing conventional synchronous generators will adversely affect auxiliary services like voltage control and frequency regulation. Nowadays, there is no requirement by grid operators for these decoupled generation plants to provide any inertial support to the grid. Hence the integration of renewable energy sources could not serve as a complete replacement of the conventional generation. These challenges require identification of new solutions, which enhance dynamic performance and improves stability of the power grid. This paper presents one of the possible solutions to cope up with these challenges. This is based on a Modular Multilevel Converter based STATCOM i.e. SVC PLUS with power intensive storage. Preliminary results show a significant contribution of the proposed system to the dynamical behaviour and stability of the power grid.

Optimum semiconductor voltage level for MMC submodules in HVDC applications

This paper presents a comparison of the achievable submodule utilization, losses and other basic figures of merit for the design of the modular multilevel converter half bridge submodules for transmission applications. Based on those figures of merit, a method to find out the optimum semiconductor voltage level for MMC submodules in HVDC Applications for a given power and boundary condition is elucidated. Based on the boundary conditions used for the examples of this paper, 4.5 kV blocking voltage is the optimum voltage level for semiconductors at transmission power of less than 900 MW. For higher transmission power the better performance was achieved by the submodule based on the 6.5 kV IGBT.